^tbrarg
CHEM BLDG
QUALITATIVE
ORGANIC ANALYSIS
QUALITATIVE
ORGANIC ANALYSIS
An Elementary Course in the
Identification of Organic Compounds
BY
OLIVER KAMM
Director of Chemical Research, Parke, Davis & Co.
Formerly Assistant Professor of Chemistry,
the University of Illinois
NEW YORK •
JOHN WILEY & SONS, Inc.
London: CHAPMAN & HALL, Ijmited
1923
K2
Copyright, 192ie
By OLIVER KAMM
PRESS OF
1 BRAUNWORTH & CO.
4/25 BOOK MANUFACTURERS
BROOKLYN, N. Y.
PREFACE
The teaching of Qualitative Organic Analysis Is gradually-
receiving recognition as an important factor in the training of
the chemist. In 1905, the subject was taught in only two or
three universities; ten years later courses were offered in from
fifteen to twenty of the leading schools in this country; and in
1918 the subject was prescribed for all colleges undertaking the
training of chemists under the supervision of the United States
Government. Only the armistice prevented the institution of
this sweeping innovation in chemical curricula.
Qualitative Organic Analysis has not been taught generally
because of the assumption on the part of chemists that the multi-
plicity of organic compounds excludes the possibility of a sys-
tematic procedure. This is the opinion of those who have not
taught the subject; those who have had experience in presenting
the work both in the classroom and the laboratory realize that
Qualitative Organic Analysis is capable of logical and systematic
treatment and that it is of fundamental importance in the elemen-
tary training of the chemist in the organic field.
The course here outlined is essentially that offered by the
writer at the University of Ilhnois in 1920. The basis for its
claim to systematization is outlined in Chapters I and 11. The
most radical individual departure from other analytical schemes
consists in the subdivision of organic compounds into seven
solubility groups and the application of this classification to a
systematic procedure.
The chemist to whom most credit is due for the development
of organic qualitative analysis is Professor S. P. MuUiken. The
appearance of his exhaustive reference book on the "Identifica-
tion of Pure Organic Compounds," Vol. I, in 1905 is obviously
the beginning of this line of work. The authors of foreign texts
iii
1 14-lS
\
iv PREFACE
on the subject have curiously avoided crediting the pioneer in
the field. The present writer extends such recognition with
pleasure. He wishes also to offer hearty acknowledgment to hii
teacher and colleague, Dr. C. G. Derick, at whose suggestion the
presentation of this text was undertaken. The procedure here
outlined is based upon a course offered by Dr. Derick in 1908
and subsequently developed with his constant sympathetic help
and encouragement during the years 1911-1915.
The course outlined in this text is intended to follow the
usual work in synthetic organic preparations; Part A corre-
sponds to the classroom work, while Part B embodies the actual
laboratory directions. The steps required in the identification
of an unknown are outlined in Chapter VI and are treated in
more detail in the subsequent chapters in the order in which
they are required in an actual identification. The work is usually
apportioned as follows for a one-semester course of sixteen weeks,
covering thirty-two laboratory periods of three hours each.
Solubility Tests on Known Compounds,
Chapter VIII. One week.
Classification Reactions on Known Compounds,
Chapter IX. Five weeks.
Identification of Six or Eight Individual Compounds,
Chapters VI -XI. Six weeks.
Examination of Mixtures,
Chapter XII. Four weeks.
In certain branches of stud}'', and particularly in Chemical
Engineering, the schedule will not permit instruction in Qualita-
tive Organic Analysis as a separate course. In such classes it
has been found best, nevertheless, to present an abbreviated six
or eight weeks' course in place of the latter part of the second
semester's work in organic synthesis. Such an abbreviated course
should consist of the solubility work of Chapter VIII, selections
from Chapter IX so as to require only about three weeks' work,
and the identification of about four individual compounds.
The classified tables in Part C have not previously been used
in actual laboratory instruction and suggestions in regard to cor-
rections and additions from those who have occasion to use them
in classwork will be appreciated. The tables are intended only
for preliminary aid before resorting to the advanced reference
books. Formulas and specific instructions for the choice of deriva-
PREFACE V
lives are omitted for pedagogical reasons; the former are usually
superfluous and the latter should be a part of the student's own
work based upon the principles discussed in Chapter X.
The writer takes this opportunity to acknowledge his indebt-
edness not only to the extensive works by Mulhken, but also to
the authors of two smaller but nevertheless very valuable manuals
that have from time to time been used as text-books in his courses,
namely: Clarke's "Handbook of Organic Analysis" and Noyes
and MuUiken's "Laboratory Experiments on the Class Reac-
tions of Organic Substances (1897)." He also wishes to express
his gratitude to Dr. C. S. Marvel, who has read the manuscript
and offered other valuable assistance, to Dr. E. A. Wildman,
who has read the proof, and to Mr. A. O. Matthews, who has
prepared the drawings.
Oliver Kamm.
Detroit, Michigan
October, 1922.
CONTENTS
PAGE
A. Theoretical Part
I. The Method of QuaUtative Organic Analysis 1
II. The SolubiUty Behavior of Organic Compounds 8
III. Classification Reactions : Hydrocarbons and Their Oxygen and
Halogen Derivatives 29
IV. Classification Reactions: The Simple Nitrogen and Sulfur
Compounds 59
V. Classification Reactions: Compounds with Unlike Subs tituents 81
B. Laboratory Directions
VI. Procedure for the Analysis of an Individual Compound 107
VII. Determination of Physical Constants and Analysis for the
Elements Ill
VIII. Laboratory Work on the Solubility Behavior of Organic
Compounds 126
IX. Laboratory Work on Classification Reactions of Organic
Compounds 132
X. Preparation of Derivatives 148
XI. Quantitative Analysis of Substituent Groups 167
XII. Examination of Mixtures 176
C. Classified Tables of Compounds 187
Index 241
^
oTthT
QUALITATIVE ORGANIC ANALYSIS
PART A
CHAPTER I
THE METHOD OF QUALITATIVE ORGANIC ANALYSIS
The multiplicity of organic compounds, the instability of
many of the individual members when compared with the more
common inorganic compounds, and the relative complexity of
mixtures of organic substances (particularly many of the mix-
tures obtained from natural products) make organic analysis
appear difficult to the uninitiated. Inorganic analysis, on the
other hand, appears simple and systematic because we have too
arbitrarily limited it more or less to a method for the analysis
of the commoner ions; no scheme has yet been proposed for a
complete and systematic method for the analysis of inorganic
co?npounds.
In the present procedure for qualitative organic analysis no
attempt is made to outline for organic chemistry that which has
not yet been accomplished in the older inorganic field; it is
intended as an elementary introductory course to form a ground-
work for the more specialized lines of advanced organic analysis,
many of which still lie mainly in the realm of research.
In discussing the procedure for the identification of an
organic compound, it is well for us to differentiate between
(a) the method of characterizing new organic compounds which
2 QUALITATIVE ORGANIC ANALYSIS
have not been described previously and (6) the more rapid method
that may be apphed to those compounds which have already
been subjected to characterization. It will be found, however,
that the qualitative procedure often will be applicable even to
the identification of compounds not yet described in the litera-
ture.
THE CHARACTERIZATION OF AN ORGANIC COMPOUND
When a new compound is prepared in the laboratory or when a
new individual is isolated from some natural source, extensive
work is often required for the complete assignment of its struc-
ture; i.e., for the characterization of the compound. The usual
steps in the procedure for the assignment of structure to both
organic and inorganic compounds are as follows:
(1) Isolation and Purification,
(2) Qualitative Analysis,
(3) Quantitative Analysis,
(4) Molecular Weight Determination.
These four steps are often sufficient for the characterization of
an inorganic compound; on the other hand, organic compounds
almost invariably require a fifth consideration:
(5) Assignment of Structure According to the Atomic
Linking Theory,
(a) Analytical Method of Structure Proof,
(6) Synthetical Method of Structure Proof.
The importance of the last step may be illustrated best by a
specific example, A definite chemical individual is isolated from
a natural product. Qualitative analysis demonstrates the pres-
ence of carbon, hydrogen, and oxygen. Quantitative analysis
shows these three elements to be present in the proportions
2C : 4H : 10.
The formula for the compound can therefore be written (C2H40)z.
Molecular weight deteiminations demonstrate the value of x to
METHOD OF QUALITATIVE ORGANIC ANALYSIS 3
be three ; the correct molecular formula can now be adopted as
C6H12O3. A glance at the literature shows, however, that this
formula represents the true composition of about eighty organic
compounds; obviously then these compounds possess different
internal structures and it is necessary to ask the question,
" How are the atoms arranged within the molecule?" It is
by answering this question that we can differentiate between
these various isomers, and this answer is obtained by applying
in the aid of the Atomic Linking Theory the analytical and
synthetical methods for structure proof.
If the procedure outlined above were the one actually used
in a laboratory course in qualitative organic analysis, the iden-
tification of an organic compound would be a very difficult and
laborious task indeed. It is fortunate, therefore, that a simpler
method is at hand.
In connection with the identification of an organic compound,
time will usually not permit a quantitative analysis for the ele-
ments (step three, above), since it is desired to identify a com-
pound not in a few days' time, but during a few hours. For the
same reason, molecular weight determinations are applied only
in exceptional instances. Step five, the assignment of structure,
often involves years of investigational work. Fortunately, this
work has already been accomplished for an enormous number of
organic compounds, and the path has thus been cleared in the
direction of qualitative identification when these compounds are
again met.
THE METHOD OF SUPERPOSITION
A given unknown organic compound is said to be identical
with a known when the two compounds agree perfectly in all of
their physical and chemical properties. Such a method is of
course impractical, and actual laboratory experience teaches us
that agreement between several of the physical properties
together with uniformity of the chemical reactions of the two
compounds,^ justifies us in assuming complete agreement in all
properties either physical or chemical.
"■This implies also that the products of the reactions (derivatives) must
agree iu their physical constants.
4 QUALITATIVE ORGANIC ANALYSIS
The method of superposition Hes at the basis of any scheme of
identification, but because of the multiplicity of organic com-
pounds this method in itself would prove of little value; a scheme
of analysis dependent upon it alone would lead to an immense
amount of unnecessary work without the equivalent return in
development of logical thinking and without the accumulation of
a systematic knowledge of organic chemistry which may be best
developed in the qualitative field. In order to be of value, the
method of superposition must be preceded by a systematic
method of elimination.
THE METHOD OF QUALITATIVE ORGANIC ANALYSIS
The steps to be taken in the rapid identification of a compound
which has previously been characterized are as follows :
1. Purification of the compound and determination of the
most common physical constants,
2. Qualitative analysis for the elements,
3. Determination of solubility behavior,
4. Application of class reactions to those types indicated
by tests 1, 2, and 3,
5. Use of the literature on known classes of compounds,
6. Preparation of derivatives and determination of physi-
cal constants of these derivatives.
The systematic method for the identification consists in
locating first not the individual compound but the class or prefer-
ably the homologous series to which the compound belongs.
Let the student be given an unknown organic compound,
which may be any one from among thousands of known com-
pounds. Obviously, it would be a waste of time to search
through the literature in order to find constants and reactions of
known compounds which check with the physical and chemical
properties of the unknown. We shall seek first the " class "
to which the unknown belongs. The determination of its melt-
ing- or boiling-point will exclude certain classes of compounds;
the qualitative analysis for the elements (C, H, N, S, X, etc.),
will further limit the possible classes, and after the apphcation
METHOD OF QUALITATIVE ORGANIC ANALYSIS 5
of the prescribed solubility tests the possibihties will be still more
limited. Furthermore, the " class reactions," the so-called
homologous tests, will limit the number of classes to very few,
and preferably to only one. At this stage, but not before, may the
literature be consulted. The position of the compound within a
given class will then be determined by means of its physical
constants, and to prove absolutely that the process of reasoning
is correct, as well as to differentiate between several possible
individuals, one or more derivatives are prepared and identified
by means of their physical constants.
THE THEORETICAL BASIS FOR QUALITATIVE ORGANIC
ANALYSIS
The Value of Homology. — In the procedure for qualitative
identification of an unknown, as sketched above, systematization
is possible because of the occurrence of homology. Fortunately,
nature has divided the immense number of organic compounds
into certain definite series called homologous series. In an homo-
logous series a given member differs from the preceding or succeed-
ing member by the constant difference, CH2. For example, in
the homologous series comprising the monobasic paraffin acids,
we have as the first five members:
HCO2H Formic acid,
CH3CO2H Acetic acid,
CH3CH2CO2H Propionic acid,
CH3CH2CH2CO2H Butyric acid,
CH3CH2CH2CH2CO2H Valeric acid, etc.
From a scientific standpoint, the existence of homology is of
fundamental importance for two reasons : (1) The chemical prop-
erties of every member of an homologous series are the same;
they differ only in the speed of reaction, not in the kind of reaction.
(2) The physical properties of the members of a given homologous
series are different. For example, in the above homologous series
we note in each member the presence of a carboxyl group together
with a saturated radical, hence each acid must possess the chemical
properties of these two radicals, i.e., must possess the same chemi-
6
QUALITATIVE ORGANIC ANALYSIS
cal properties. (We note, however, that in the above series, the
first member possesses a carboxyl group united to a hydrogen
atom and we may expect therefore a variation in certain chemical
properties.) On the other hand, each member of a given homo-
logous series may be differentiated from any other member by
means of physical properties.
TABLE I
Sp. gr.
25°/25°
M.p.
of
p-tolui-
dide
M.p.
of
Duclaux
Name
M.p.
B.p.
p-nitro-
benzyl
con-
stant
ester
Formic acid
+ 8°
101°
1.291
.52°
31°
4
Acetic acid
+ 15°
118°
1.051
153°
78°
7
Propionic acid ....
-22°
141°
0.991
123°
31°
11
n-Butj'iic acid ....
- 8°
162°
0.956
74°
35°
18
Isobutyric acid ....
- 5°
155°
0.946
109°
liquid
25
n-Valeric acid
-58°
185°
0.937
70°
28
The homologous series to which the unknown compound
belongs must be determined mainly by means of the chemical
reactions characteristic of its groups and then its physical prop-
erties will reveal the position of the compound in the homologous
series. The principle of homology has been kept in mind in
outlining the method of analysis given above. In actual prac-
tice, it is found more convenient to consider classes of organic
compounds in place of homologous series. In some instances
these classes may be identical with given homologous series,
whereas in other cases a class may comprise members from several
homologous series; for instance, under primary aromatic amines
we shall classify aniline, «-naphthyl amine, o-anisidine, p-amino-
acetophenone, etc. Although each one of these four individuals
belongs to a different homologous series, they all exhibit analo-
gous chemical reactions in respect to the amine group.
In the subsequent laboratory work, we shall seek to apply the
systematic procedure outlined above under " The Method of
Qualitative Organic Analysis."
METHOD OF QUALITATIVE ORGANIC ANALYSIS
REFERENCES
The following books are suggested for reference in connection
with the study of Qualitative Organic Analysis: Mulliken: The
Identification of Pure Organic Compounds, Vols. I, II, and III.^
Rosenthaler: Nachweis Organischen Verbindungen. Clarke:
Handbook of Organic Analysis. Weyl: Methoden der Organ-
ischen Chemie. Allen : Commercial Organic Analysis. Sherman :
Organic Analysis (Foods).
The student, from his previous training in organic chemistry, is expected
to be familiar with reference books such as Richter's Lexicon and Beilstein's
Handbuch, and he should cultivate a familiarity with Chemical Abstracts
as a source for the more recent work.
1 Volume IV of MuUiken's work will be available in 1923.
CHAPTER II
THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS
Physical Properties and Molecular Structure. — The atomic
hnking theory attempts to explain the physical and chemical
properties of organic compounds by means of the linking together
of atoms. In applying the theory for the prediction of the physi-
cal properties of organic compounds, the following considera-
tions are of fundamental significance:
(a) The kind and number of atoms present (chemical
composition),
(6) The mode of linking of the atoms (constitution),
(c) The spatial arrangement of the atoms (configuration).
In any systematic method for the identification of organic
compounds, both physical and chemical properties are utilized
for locating the class, or, preferably, the homologous series to
which the unknown belongs, and subsequently specific physical
tests are applied to locate the individual within the series.
Unfortunately for organic analysis, the study of the relationship
between physical properties and molecular structure is still a
relatively undeveloped field, certainly so when viewed from the
standpoint of potential possibilities.
In the present chapter, we shall discuss in an elementary
manner the relation to molecular structure of only one physical
property, that of solubility. This topic is chosen because it lies
at the basis of the present scheme of analysis. The discussion
is intended for the beginner; the experienced analyst is able to
utilize efficiently generalizations based upon other physical prop-
erties as well.
Prediction of Solubility. — From the atomic linking structure
of an organic compound, we may with fair assurance predict in
8
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 9
a qualitative way its solubility behavior. For the purposes of
qualitative organic analysis we may reverse this procedure, and
from the results of solubility tests draw certain inferences con-
cerning the nature of a given unknown ; these will depend upon the
results of an elementary analysis of the compound as well as upon
its physical constants. It is for this reason that qualitative
analysis for the elements and ■ a determination of the physical
constants should precede conclusions drawn from the solubility
behavior of a given compound.
Arbitrary Classification of Solvents. — In discussing the sol-
ubility behavior of organic compounds, we shall for convenience
place the solvents used in two groups:
(a) Inert solvents,
(6) Reaction solvents.
This division, we shall find, is not altogether sharp. Under Inert
Solvents we shall arbitrarily group those solvents, like water,
ether, alcohol, benzene, etc., which may be predicted to exert their
solubility effects because of a structural relationship to the sub-
stance dissolved.
Under Reaction Solvents we shall group those solvents which
cause solubility because of a chemical reaction of the kind ordi-
narily expressed by equations; viz., the neutralization of an acid
by a base with the production of a soluble salt. The fact that
solubility in water may produce ionization or hydrolysis in certain
cases and solvation in general is recognized, but nevertheless an
arbitrary distinction of this kind will prove of value in the sub-
sequent discussion.
RULES FOR THE PREDICTION OF SOLUBILITIES IN THE
INERT SOLVENTS
For the prediction of the solubihties of organic compounds in
the Inert Solvents we shall have occasion to apply four fairly
general rules:
I. A substance is most soluble in that solvent which is
most closely related structurally to the solute.
II. As we go higher in a given homologous series, the
members become more and more, in their physical
10 QUALITATIVE ORGANIC ANALYSIS
properties, like the hydrocarbons from which they
may be considered as being derived.
III. Compounds of very high molecular weight, such as
highly polymerized compounds, exhibit decreased
solubility in the inert solvents.
IV. The solubility behavior of solid compounds is depend-
ent upon the molecular aggregation in the solid
state.
The four solubility rules have been presented in the order
given for the reason that in the prediction of the solubility behavior
of a known compound they will be used in this order. Knowing
the formula for a given compound, we proceed first to predict its
solubility in a special solvent on the basis of relationship in struc-
ture between the solute and the solvent. (Rule I.) Next, we
must consider the effect of position within the homologous series
(Rule II) and for this purpose we must be able to predict, of course,
the solubility behavior of the hydrocarbons. Finally, we must
consider possible limitations imposed by the two qualifying Rules
III and IV.
Discussion of the Rules of Solubility. — Rule I. A substance
is most soluble in that solvent which is most closely related structur-
ally to the solute. This rule will receive verification from the ele-
mentary applications that will be presented throughout this
chapter. Hexane is insoluble in water (1 : 1000), which is in
accordance with what we should expect from the dissimilarity
in structure between hydrocarbons and water. On the other
hand, hexane dissolves in three parts of methyl alcohol, while in
ethyl alcohol it is soluble in all proportions; ethyl alcohol is closely
enough related to hexane in structure to produce miscibility.
Naturally we shall not hesitate, therefore, to predict that hexane
will dissolve in all proportions in a very intimately related sol-
vent, octane; in fact, such a mixture will give rise to what the
physical chemist terms " an ideal solution '' since it obeys the same
laws that ordinarily apply only to extremely dilute solutions.
Although ethyl alcohol and hexane dissolve in all proportions
and although this relationship holds for many of the homologues
not only of the series C„H2^ + 2 but also for the series C„H.„, C„H2„_6,
etc., we find that paraffin hydrocarbons of sufficiently high molec-
ular weight are not completely miscible in ethyl alcohol; for
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 11
example, ordinary kerosene requires several volumes of ethyl
alcohol for complete solution. This behavior is covered by Rule
III. Although kerosene is not completely miscible in ethyl alco-
hol, we may predict, according to Rule I, that it will dissolve
more readily in an alcohol of higher molecular weight (butyl
alcohol), which is more closely related to kerosene in composition.
Actual experiment verifies this prediction.
A few additional specific examples dealing with some common
organic compounds will be presented here to illustrate the apph-
cation of Rule I.
TABLE II
Solubility of p-Dibromobenzene in Various Solvents at 50°
Solvent
Grams
solute per
100 grams
of saturated
solution
Solvent
Grams
solute per
100 grams
of saturated
solution
HOH
0.0
20
26
27
30
67
CH3OH
CSj
72
CH3CH2OH
C6H6
71
CH3CH2CH2OH
(CH3)2CHCH20H
CeHsBr
54
The effect of substitution in organic compounds by halogen
usually results in decreased solubility in the inert solvents; the
effect of halogen is therefore analogous to an increase in number
of carbon atoms. p-Dibromobenzene is insoluble in water, but is
extremely soluble in a solvent like benzene which is closely related
in structure to the solute. The alcohols lie intermediate in struc-
true between water and the hydrocarbon solvents, and this cor-
responding effect is reflected in the data of Table II. Ether is
still more closely related to the hydrocarbons and the above
solubility value is such as might be predicted qualitatively. The
solubility of p-dibromobenzene is less in bromobenzene than in
an equal weight of benzene, but this irregularity is removed when
solubility is expressed in grams of solute per mole of solvent.
12
QUALITATIVE ORGANIC ANALYSIS
TABLE III
Solubility of Naphthalene in Various Solvents at 20'
Solvent
Grams
naphthalene
per
100 grams
solvent
Solvent
Grams
naphthalene
per
100 grams
solvent
HOH
0.003
8.2
9.8
14,0
13.0
23
CH.,CH2CH2C02H
(CH3)2CHCH2C02H ....
CHCI3
22
CH3OH
17
CHiCH^OH
31
CH3CH2CH2CH2CH2CH,,
CHaCO^H
CS2
36
36
CH^CILCG?!!
28
Problem 1. — Interpret the data in Table III in accordance with pre-
dictions based upon Rule I. Why would the solubility of naphthalene in
mono-hydroxy alcohols up to Ce be predicted to lie below 14 g. per 100 g.
solvent? Given the solubility in acetic acid, do the solubilities in propionic,
butyric and valeric acids agree with predictions? Why would one expect
naphthalene to be less soluble in toluene than in benzene? Predict qualita-
tively the solubility of naphthalene in the solvents formic acid, heptanoic
acid, ethyl benzene, etc. Compare the solubiUties in hydrocarbons of the
two series C„H2„+2 and CnRin-e, where n = Q. Do the facts agree with pre-
dictions? Predict qualitatively the solubility of naphthalene in ethyl acetate.
Prediction of solubility in the inert solvents such as carbon disulfide,
carbon tetrachloride, chloroform, etc., is somewhat more difficult. In these
instances it is sometimes convenient to consult the following table of dielectric
constants. No definite relationship between dielectric constants and solu-
bilities has been developed since unknown factors are involved; nevertheless,
the dielectric constants may be used where they do not conflict with the more
basic generalization given in Rule I.
TABLE IV
Dielectric Constants of Some Organic Solvents at 18° to 20°
Water 81
Methyl alcohol 32
Ethyl alcohol 26
Propyl alcohol 22
Isobutyl alcohol 19
Isoamyl alcohol 16
Ethyl bromide 10
Acetic acid 9.7
Ethyl acetate 6.5
Bromobenzene 5.2
Chloroform 5.2
Ethyl ether 4.4
Carbon disulfide 2.6
Benzene 2.3
Carbon tetrachloride. . . 2 . 25
Hexane 2,0
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 13
According to Rule I, we may predict that naphthalene will dissolve to a
limited extent in either ethyl alcohol or glacial acetic acid. A selection of the
most efficient of these two solvents would be difficult without actual experi-
ment. The dielectric values, however, indicate that acetic acid will prove
superior. Explain. On the other hand, benzene and hexane differ only
slightly in dielectric constants. Since benzene is very much more closely
related in structure to naphthalene than is hexane, we find that the solubility
of naphthalene is considerably greater in the former solvent: Rule I takes
precedence over predictions based upon dielectric constants.
Problem 2. — Look up in Seidell, "Solubilities of Inorganic and Organic
Compounds," 1919, p. 136, the solubihty of benzoic acid in various organic
solvents. Compare these values with the corresponding dielectric constants.
Although the two common solvents, chloroform and carbon tetrachloride,
are very closely related in composition, the table of dielectric constants
suggests considerable variation in the solvent powers of these two com-
pounds, which prediction is in agreement with actual experience. In many
instances, chloroform exhibits an unusual solvent power. This is especially
noticeable in the solubilities of some of the well-known alkaloids, such as
atropine, quinine, cinchonine, quinidine, and hyoscyamine.
The Second Rule of Solubility. — As we go higher in a given
homologous series, the members become more and more, in their
physical properties, like the hydrocarbons from which they may be
considered as being derived. It should be noted that this statement
is very broad in its apphcation; it refers to physical properties
in general, whereas in our discussion we require only a limited
application to one physical property, that of solubihty in the
inert solvents.
Figure 1 illustrates the application of the rule to the solu-
bility in water of the aliphatic mono-hydroxy alcohols and mono-
carboxyhc acids. Beyond the members possessing five carbon
atoms the solubilities of the oxygenated derivatives rapidly
approach those of the hydrocarbons.
Many other illustrations of Rule II, together with numerical
data, will be discussed in the latter part of this chapter in con-
nection with the development of the solubility table.
The Third Rule of Solubihty. — Compounds of very high molec-
ular weight exhibit decreased solubility in the inert solvents. This
is true even when the solvent and the solute are in the same
homologous series, provided that there is sufficient difference in
molecular weight. For example, low-boiling ligroin will not dis-
solve solid paraffin in all proportions. Similarly, acetic acid will
dissolve stearic acid only to the extent of about 5 per cent at 20°.
14
QUALITATIVE ORGANIC ANALYSIS
The formula C6H12O6 immediately suggests a sugar very soluble
in water, but (CeHioOs)^ may represent a water-insoluble sub-
stance like cellulose. CH2O and CH3-C — H represent com-
pounds extremely soluble in water, whereas (CH20)j; and
(CH3-C— H)3 represent substances of limited solubility in water.
Solubility Curve
of
Acida
Alcohols
Hydroca
trbons
.50
1
■ 40
5
3
-30
Alcohols 5^ \
PU
20
v\
— Acids
10
\\
Hydrocarbons N^
V
3 4 5 6
Number of Carbon Atoms
Fig. 1.
From the reaction between an amine and an organic acid we may
isolate an amide of normal solubility. When, however, a dia-
mine, such as p-phenylene diamine or benzidine, reacts with a
dicarboxylic acid, the primary reaction-product may react again
and again to yield finally substances of very high molecular weight.
Such products are insoluble in the inert solvents. Many other
analogous instances might be cited. Among the substances of
high molecular weight we must make allowance, however, for
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 15
certain types that yield colloidal solutions; this is especially
noticeable with certain starches, proteins, and dyes.
The Fourth Rule of Solubility.— The solubility behavior of solid
compounds is dependent upon the molecular aggregation in the solid
state. It is because of this factor that the solubility behavior of
liquid compounds may be predicted more safely than that of
solids. Solubility is dependent upon the species in equilibrium
with the saturated solution. The molecular aggregation in the
solid state finds expression, however, in other physical properties;
for example, in the melting-points of the compounds. By judi-
cious use of relationships which have been pointed out in this
field, we possess a means of predicting many cases of solubility
that might otherwise be treated as exceptions.
Among compounds of a given homologous series, high
melting-points^ may often be associated with low solubility.
Among isomeric substances (space isomerism) the isomer least
stable toward rearrangement possesses the lowest melting-point
and the greatest solubility. Among position-isomers, such as
the isomeric di- and tri-substitution products of benzene, only
a fair agreement is found, with the assumption that the solu-
bilities of the isomers are in the order of their melting-
points .^
The melting-point and solubility relationships of the saturated
aliphatic dicarboxylic acids illustrate this rule (IV) among com-
pounds that are not isomeric but homologous. In this series, we
must apply Rule II separately to the acids with odd and to those
with even numbers of carbon atoms. Beyond the C7 member,
we find, however, that one group is rapidly approaching the solu-
bility of the other and both groups are rapidly approaching the
solubilities of the corresponding hydrocarbons. (See Fig. 2.)
In agreement with Rule IV, we find that the solubility of an
organic compound is greater when the saturated solution is in
equilibrium with the liquid substance than when in contact with
the solid at the same temperature. For example, at 70° benzoic
acid is soluble in water to the extent of 2 per cent provided that
the saturated solution is in contact with solid benzoic acid; when
1 This does not apply to compounds of the "salt type."
2Carnelley and Tomson, J. Chem. Soc. 53, 791 (1888); 73, 618 (1898);
J. prakt. Chem. 52, 72 (1895); 59, 30-45 (1899); J. Chem. Soc. Abstracts 92,
i, 745 (1907).
16
QUALITATIVE ORGANIC ANALYSIS
in contact with liquid benzoic acid the solubihty is three times
as large.
Physical Constants of Dicarboxylic Acids
.2 e
-189
\ 2 ^^'°
V 1/ I <i^^ A
140°
0
r\"\\\
A/"'
1 1 ' V 1
/ o 0 108°
'l05
/ 1 1 "°1
' "-
Solubility Curve
]Vf P r„rva
* 1 — 1 — 1 — 1 — 1 —
^vO.lSg 0.25g o.lOg
H V ? ^
3 4 5 6 7 8
NuuLber of Carbon Atoms
Fig. 2.
A number of other well-known examples will now be considered.
Among geometrical isomers (cis-trans type) we find that the most
fusible isomer possesses also the greatest solubility. (See Table V.)
A case analogous with the above is that dealing with the vari-
ous isomeric cinnamic acids. The ordinary stable isomer (m. p.
133°) is soluble ''n water at 25° to the extent of about one part
in 15,000 while the labile acids (m. p. 68°, 58°, 42°) are soluble
in about 100 parts of water.
Among optical isomers, dextro and laevo enantiomorphs pos-
sess identical melting-points and identical solubilities. The race-
mic form usually differs in melting-point and in solubility. Among
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 17
this class of compounds we find many examples illustrating the
fact that solubility depends upon the molecular complexity of
the solid. The tartaric acids furnish a typical illustration.
In solution, the racemic tartaric acid may be represented as
CO2H -(011011)2 -00211, as is indicated by its cryoscopic depres-
sion and its ionization constant; its solubility is controlled,
however, by the molecular complexity of the soUd. (See Table VI.)
TABLE V
Substance
M. p.
Solubility in 100 grams
solvent at 20°.
Water
Ethanol
CH— CO2H
II maleic acid
CH— CO2H
HC— CO2H
II fumaric acid
CO2H— CH
130°
286° subl.
60 g.
0.6g.
51 g.
5g.
TABLE VI
M. p.
Solubility in
100 g. water
(20°)
Solubility in
100 g. alcohol
(25°)
C4H6O6 d-tartaric acid
170°
170°
139 g.
139 g.
20.6 g.
27 g.
27 g.
2g.
C^HeOs Z-tartaric aicd
(C4H606-H20)2 '//-tartaric acid. . .
(racemic)
205-200°
Among the di- substituted benzene derivatives, we find very
often that the order of solubility lies in the order of the melting-
points. This is illustrated in the solubilities of the following sub-
stituted benzoic acids.
18
QUALITATIVE ORGANIC ANALYSIS
TABLE VII
Name of acid
Melting-point
of acids
Solubility in 1000
grams of water
at about 25°
Ortho
Meta
Para
Ortho
Meta
Para
Chlorobenzoic
142°
158°
243°
2.25
0.45
0.09
Bromobenzoic
150°
155°
254°
1.86
0.40
0.056
lodobenzoic
162°
186°
265°
0.95
0.12
0.027
Toluic
104°
110°
179°
1.18
0.98
0.35
Phthalic
230°
300°
Subl.
10.
0.13
0.0
Nitrobenzoic
147°
141°
238°
r7.4~|
2.5
13. 4j
3.4
0.3
Hydroxybenzoic
158°
200°
213°
10.8
6.5
Aminobenzoic
144°
174°
187°
5.6
3.1
In comparing the meta and para compounds in Table VII, it
will be noticed that the higher-melting isomers are also the less
soluble in water. This rule cannot at present be made more
general so as to include also the ortho isomers because a number
of well-known exceptions exist; these exceptions are indicated in
the table by the brackets. It appears probable, however, that
this irregularity is mainly disposed of in a solvent like benzene,
which is more closely related in structure to the solute. See
Table VIII.
TABLE VIII
Name of compound
Me
Iting-point
Per cent solubility at
20° in benzene
Ortho
Meta
Para
Ortho
Meta
Para
Hydroxybenzoic
Nitrobenzoic
Nitrophenol
158°
147°
44°
118°
69°
32°
38°
200°
141°
95°
90°
112°
44°
53°
210°
238°
114°
173°
148°
82°
124°
0.8
0.4
50.
5.7
23
70
60
0.01
1.0
1.5
39
2.5
48
35
0.004
0.03
0.5
Dinitrobenzene
Nitraniline
Chloronitrobenzene
Bromonitrobenzene
2 5
ro.6
12. 0
29
5
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 19
SOLUBILITY IN THE REACTION SOLVENTS
For the purpose of classification, we shall find cold concen-
trated sulfuric acid an extremely valuable reagent; its main use
consists in the subdivision of the group of compounds which we
shall call the indifferents, i.e., compounds insoluble in water and
containing neither acidic nor basic groups. We shall find that
the saturated hydrocarbons (aliphatic and aromatic) are insoluble
in this reagent under the conditions of the experiment and this
holds true with but few exceptions chiefly among the tertiary
members, for the halogen derivatives of these hydrocarbons.
The oxygenated derivatives of these compounds (alcohols,
ketones, esters, ethers, aldehydes, etc.) are almost invariably ex-
tremely soluble (occasionally with decomposition) in this solvent.
Cold concentrated sulfuric acid differs from the usual inert
solvents mainly in that it forms a more stable addition product
with the solute. The use of sulfuric acid in this solubility work
is based not upon the usual sulfonation reactions but upon the
formation of addition products from which the organic compound
may usually be recovered unchanged. For example, ethyl ben-
zoate will dissolve in all proportions in cold concentrated sulfuric
acid to produce addition products ^ of the types
[C6H5C02C2H5-H2S04] and [(C6H5C02C2H5)2-H2S04].
The ethyl benzoate may be recovered by pouring the acid solution
into ice-water.
Basic Groups. — Compounds possessing basic groups will react
with dilute hydrochloric acid to produce water-soluble hydro-
chlorides. Obviously, the degree of basicity of the amine group,
the concentration of the acid used, and the solubilities of the amine
salts are important factors, and these will be discussed in more
detail in connection with the laboratory instructions.
By far the most common basic groups are the amino and
certain substituted amino groups. Sulfonium hydroxides, certain
oximes, pyrones and their naturally-occurring derivatives (the
anthocyanins), represent basic compounds which need consider-
ation only in more advanced work.
1 J. Kendall, J. Am. Chem. Soc. 36, 2498 (1914).
20
QU^&ATIVE ORGANIC ANALYSIS
When an organic consMknd contains the group NH2, it is not
necessarily basic in natui^ in fact it may be basic, neutral, or
even acidic, the structure of that part of the molecule united to
the NH2 group exerting the controlling influence. When a hydro-
gen of ammonia is substituted by an alkyl or related radical, we
obtain a primary amine which compares favorably with ammonia
in basicity.
TABLE IX
Ammonia. . .
Ethyl amine .
Benzyl amine
Allvl amine. .
Ionization*
constant K^°
1.8 XlO-5
5.6 XIO-"
1.95X10-5
4.6 XlO-5
Diethyl amine. .
Dimethyl amine
Triethyl amine.
Piperidine
Ionization*
constant K^'
1. 26X10-'
5.35X10-*
5.9 XlO-5
1.2 XlO-»
* Scudder: Conductivity and Ionization Constants of Organic Compounds (1914). The
values are only apparent ionization constants for the reason that only, a fraction of the
amine is present as an ammonium compound. Cf. also Bredig, Zeit. Phys. Chem. 13,
289-326 (1894).
When the second and third hydrogens of ammonia are replaced
by alkyl radicals, we find that the resulting secondary and tertiary
amines are of approximately the same order of basicity as the
primary amines. (See second column of Table IX.)
If in place of alkyl or related radicals we introduce into
ammonia an aryl radical, we note a tremendous drop in the ioniza-
tion constant (Table X) to about one-millionth of its previous
value. We may predict that a second radical, but of the alkyl
type, will produce no further large change in basicity, but the
introduction of a second aryl radical will produce a second large
decrease in basicity, whereas a third aryl radical will produce a
practically neutral substance. The phenomenon produced by two
or three aryl groups may be accomplished by the introduction
of a single radical of the acyl type. A second acyl radical will
convert the nitrogen derivative into an acidic substance. That
which is accomplished by means of two acyl groups may be called
forth by a single group provided that the acyl group corresponds
to a very strong acid (sulfonic acid). Examples of all of these
cases are given in Table X.
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 21
TABLE X
Substance
Ionization constant
Reaction
C6H5NH2
CCH5NHCH3
C6H5N(CH3)2....
(C6H5)2NH
(C6HO3N
C6H5CONH2....
CH3CONH2
CH3CONHC6H5
•CO-
C6H4 p „ NH
C6H5SO2NH2....
Kf° = 5 X 10-10
^B° = 3 X 10-10
A'b^° =0.3X10-1^
AS°°=4. 0X10-1^
A'i^°=5 XIO-^
Basic
Basic
Basic
Almost neutral
Neutral
Practically neutral
Practically neutral
Practically neutral
Acidic
Acidic
Among the basic compounds we shall find therefore primary
(I), secondary (II), and tertiary (III) amines, provided that not
more than one of the substituting radicals is an aryl radical.
The nitrogen may be part of a ring structure, as in pyridine and its
derivatives. The quaternary ammonium bases, (R)4==N — OH,
are very strong bases like the inorganic hydroxides, but they are
usually met in the form of their neutral salts.
In addition to the basicity of the compound, we must con-
sider also its solubility in water in order to predict its solubility
in dilute aqueous hydrochloric acid. Amines of very high molec-
ular weight occasionally possess such a slight solubility in water
that they fail to dissolve in dilute acid. This instance is illus-
trated by the following set of equilibria in which the reaction is
shifted to the extreme left due to the insolubility of the free amine.
Usually, however, the concentration of amine produced by hydrol-
ysis is less than that which corresponds to its solubility in water,
and therefore the amine is soluble in dilute acid.
+H2O +HC1
RNH2 ;=± RNH2 7 RNH3OH ^==3- RNH3CI
(Solid) (Dissolved) — H2O — HCl (Dissolved)
22
QUALITATIVE ORGANIC ANALYSIS
ACIDIC GROUPS
Among the common acidic groups may be listed the following:
Carboxyl. — C^O— H,
Sulfonic, — S=0
\0H,
Phenol, Ar— O— H,
Oxime, =N— O— H,
Thiophenol, Ar— S— H,
Enolic type, — C^C— H,
C=0 C=0,
Sulfone amide, — S==0
\NHs
OH O
Imide, —C^ N— C^.
I or II nitro
-CH.-N<
O
-CHR— N
^
O,
o
\
o.
Compounds possessing these groups will in general dissolve in
dilute NaOH solution since their sodium salts are soluble. The
most common exception is to be found among those types which
are very feebly acidic. When such members are also high in
molecular weight, and therefore very sparingly soluble in water,
we may observe insolubility in dilute aqueous alkali.
Problem 3. — The sodium salt of a high molecular weight phenol was
prepared by adding the calculated quantity of sodium ethylate to an alcoholic
solution of the phenol. The sodium salt was filtered with suction and washed
with water. When the compound was analyzed, sodium was found prac-
tically absent. Write the equation (showing equilibria) to explain the
reactions that took place when the salt was washed with water.
Problem 4. — Write the enolic or "aci" formulas corresponding to the
formulas given above for imides, I and II nitro compounds, sulfone amides,
and enols. Note that all of the acidic groups may be considered as pos-
sessing an hydroxyl group united to an unsaturated atom.
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 23
The Solubility Table.— In order to use solubility data effect-
ively in an elementary analytical procedure, it is found con-
venient to group organic compounds into seven solubility groups.
Table XI illustrates such a division. It will be noticed that only
a limited number of solvents is used in this solubility plan; viz.,
water, ether, benzene, cold concentrated H2SO4, dilute HCl, and
dilute NaOH. The use of a greater number of solvents would
lead to a more cumbersome scheme with greater numbers of
irregularities; we may, however, secure valuable additional infor-
mation about any individual group from the use of special solvents.
We shall now proceed to develop this solubility scheme and to
place various common classes of compounds into the proper
solubility groups. This is done not only to develop an ability to
predict solubility behavior, but in order to emphasize the fact
that this solubility table, which will be used later in the procedure
for analysis, need not be an object of memory work. This table
need not be overburdened with many classes of compounds of
the " mixed type " where several unlike substituents are present;
these types will call forth no special difficulties in the analytical
procedure.
To predict solubility we begin with a knowledge of the solu-
bility behavior of hydrocarbons; the solubility of other classes
of compounds will then be predicted according to the rules that
have been discussed for both " Inert " and " Reaction " solvents.
In the laboratory, methane, ethylene, and acetylene, were pre-
pared and collected over water; long before taking up the study
of chemistry we knew that gasolene and kerosene (mixtures of
hydrocarbons) do not dissolve appreciably in water. In the
laboratory, benzene was used for extractions from aqueous solu-
tions partly because of its limited solubility in water. It is appar-
ent, therefore, that the hydrocarbons (saturated paraffins, cyclo-
paraffins, unsaturated aliphatics, olefines, and aromatics) are
insoluble in water. ^ This is true also of the halogen substitution
products of the hydrocarbons. Since these compounds contain
neither acidic nor basic groups they are classified as indifferents,
1 The hydrocarbons are insoluble for the purposes of this classification.
Hexane is soluble in water only to the extent of 1 part in 1000 and the
members higher in this homologous series decrease in solubility approxi-
mately according to the rule 1 : ^ : | : ^. Compare this regularity with the
solubilities of n-amyl, n-hexyl and n-octyl alcohols given in Table XTI.
24
QUALITATIVE ORGANIC ANALYSIS
and since with few exceptions (pages 19 and 37), they are insoluble
in cold concentrated H2SO4, we may conclude that the paraffin
hydrocarbons, the aromatic hydrocarbons, and their stable halogen
substitution products fall in Group VI .
TABLE XI
Solubility Table (General Plan)
Water Soluble
Group I
Soluble ii
Ether
Group II
Insoluble
in Ether
and Ben-
zene
B
Water Insoluble
Group III
Soluble in
dil. HCl
Group IV
Soluble in
dil. KOH
IndifFerents
Hydrocarbons and their ox-
ygen and halogen deriva-
tives
Group V
Soluble in cold
con. H2SO4
Group VI
Insoluble ii
cold con
H2SO4
Other indif-
ferents con-
taining, N, S,
etc.
Group VII
The most common oxygen substitution products of the hydro-
carbons to be considered are the alcohols, aldehydes, ketones,
acids, and esters. The solubility behavior of these derivatives
may be predicted by applying Rules I and II. Solubility data
for the mono-hydroxy alcohols in water is shown in Table XII.
TABLE XII
Alcohol
Solubility in 100
grams H2O at 20°
Alcohol
Solubility in 100
grams H,0 at 20°
Methyl
00
00
00
00
10
9
Isoamyl
n-Amyl
n-Hexyl
n-Heptyl
n-Octyl
2.5
Ethyl
Propyl
1.5
0.5
Isopropyl
Isobutyl
0.03
n-Butyl
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 25
The lower members in this group of alcohols are closely related
to the solvent (water), i.e., the hydroxyl group forms a large pro-
portion of the weight of the molecule; the lower members in the
above series are therefore predicted to be very soluble in water
and facts agree with this prediction since the first four members
are found to be soluble in water in all proportions. However,
as we go higher in this homologous series, the compounds become
more and more in their solubility behavior like the hydrocarbons
from which they are derived (Rule II). The hydrocarbons are,
however, insoluble in water and this is found to be true of alcohols
of high molecular weight. For practical purposes, C.5 will be con-
sidered as the dividing line; mono-hydroxy alcohols with fewer
than five carbon atoms will be classified as water-soluble and those
with more than five carbons will be grouped as water-insoluble.
From analogy in structure to ether, we may predict that the alco-
hols are soluble in ether. The alcohols of low molecular weight
(Ci to C5) are placed, therefore, in Group I and those of high molec-
ular weight (indifferents and soluble in H2SO4) are placed in
Group V.
Similar considerations hold for aldehydes, ketones, acids, and
esters.
R
1
R
1
R
1
R
R
1
1
C=0
1
C=0
1
C=0
C=0
1
0
\
1
\
\
1
H
R
OH
OR
R
Aldehyde
Ketone
Acid
Ester
Ether
In the lower members, oxygen forms a considerable proportion of
the weight of the molecule and the lower members (less than five
carbon atoms) are quite soluble in water.^ The higher members,
again, are found to approach the corresponding hydrocarbons in
their solubility behavior; they are insoluble in water (Rule II)
but are soluble in ether (Rule I).
Aldehydes, ketones, monocarboxylic acids, and esters of low
molecular weight (up to C4) are placed in Group I, while aldehydes,
1 The effect of oxygen in producing water solubility in various aliphatic
compounds lies in the order —C- — OH > C=0 > OH > C— O— C
26
QUALITATIVE ORGANIC ANALYSIS
ketones, and esters of high molecular weight, being indifferent
and soluble in sulfuric acid, are placed in Group V. The water-
insoluble acids are placed, however, in Group IV. Why?
TABLE XIII
Solubility of Various Compounds in Water at About 20°-25° in Parts
PER 100
Number of
Carbon Atoms
Aldehyde
Ketone
Acid
Ester
Ci
Miscible
Miscible
20
Iso 11
Normal 3.6
1
Miscible
Miscible
Miscible
Iso 20
Normal 00
4
C2
Miscible
Cs
C4
C5
Miscible
25
4.0
8
2
Diethyl ether is soluble in fifteen parts of water at 20°, but
the ethers of higher molecular weight are less soluble (Rule II),
and therefore fall in Group V.
The mono-amino derivatives of the hydrocarbons are deriva-
tives of a compound (ammonia) which is very soluble in water.
The lower members in which the amino group represents a large
part of the molecule, are expected therefore to be water-soluble.
The higher members will resemble, however, the hydrocarbons
(Rule II) ; they are found to be insoluble in water. The amines
of low molecular weight (Ci to Co) must be classed in Group I,
and those of high molecular weight in Group III because of the
presence of the basic group. Among the aralkyl amines,
ArC„H2„NH2,
the benzene nucleus is equivalent in its solubility effect to about
four aliphatic carbons. Benzyl amine although possessing seven
carbon atoms is water-soluble. Among the branched chain com-
pounds, two methyl side-chains are qualitatively equivalent in
solubility effect to one chain-carbon atom.
SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 27
Problem 5. — Refer to the solubility data in Table XII and predict the
approximate solubility in water of (a) benzyl alcohol and (6) amylene hydrate,
CH3
I
CH3CH2 — C — OH. The observed values are (a) 3 to 4 parts per 100 and
I
CH3
(6) 12 parts per 100.
Problem 6. — Aniline, which possesses one CHo group less than benzyl
amine, is soluble in water only to the extent of 1 part in 30. Explain this
apparent anomaly. See also Tables IX and X.
In the discussion of the effect of substituents upon the basicity
of amines (page 20), we found that certain groups (acyl groups,
a second aryl group, etc.) removed the basicity. Such compounds
are often spoken of as " negatively substituted amines," and must
be classified among the indifferents, and since they contain nitro-
gen are placed in Group VII, irrespective of their behavior toward
sulfuric acid. Amides of low molecular weight (R-C0-NII2,
where R is Ci to 4) are water-soluble and sparingly soluble in the
hydrocarbon solvents; they therefore fall mainly in Group II.
It is to be noted that although solubility in ether or benzene
is used to differentiate between Groups I and II, these solvents
are not required for assigning any classes of compounds to the
remaining five groups of the Table. Thus, certain compounds
falling into Groups III or IV may be very soluble in ether, while
other members are almost insoluble in ether. Similar variations
are noticed especially in Group VII. These are facts of value to
an experienced analyst but they do not affect the classification
into the seven main groups; for further subdivision of these
groups such solubility data might be utilized.
The Effect of Polysubstitution in the Oxygenated Deriv-
atives of the Hydrocarbons. — The mono-hydroxy and mono-car-
boxy derivatives of the hydrocarbons are soluble in ether and in
benzene. The presence of several hydroxyl or of several carboxyl
groups will decrease solubility not only in benzene but also in
ether. The compounds become more like water in structure and
less like the hydrocarbons and ether.
For example, propyl alcohol is miscible with ether and benzene
in all proportions, but the presence of two or three hydroxyl
groups causes a very low solubility in ether and insolubility in
benzene. Such compounds will be placed in Group II. As we
28
QUALITATIVE ORGANIC ANALYSIS
TABLE XIV
Alcohols.
Solubility in ether.
Solubility in benzene
CH3CH2CH2OH
Miscible
Slightly soluble (7%)
Slightly soluble (3%)
Insoluble
Miscible
CH3CHOH • CH2OH
Almost insoluble
CH2OHCH2 0112011
Insoluble
CH2OHCHOHCH2OH
Insoluble
go higher in a given homologous series Rule II must be applied.
For example, the compound
CH3CH2CH2CH2CH2CH2 • CHOH • CH2OH
will be appreciably soluble in ether, despite the presence of two
hydroxyl groups.
The dicarboxylic acids are solid compounds the solubility
behavior of which has received consideration in the discussion of
Rule IV.
The simple carbohydrates are rich in hydroxyl groups and are
consequently very soluble in water but insoluble in ether. High
molecular weight carbohydrates (CeHioOs)^, such as starches and
cellulose, are insoluble in water as well as in ether. The insolu-
bility of most starches in cold water is controlled also by the
physical structure of the starch granules. In hot water, the
external membranes of the cells are broken and a colloidal starch
solution results.
The presence of both hydroxyl and carboxyl groups in the
same molecule, especially in low molecular weight compounds,
tends to cause ether insolubility. In the absence of any unusual
complexity in the solid state, there results great solubility in water;
examples are glycolic, lactic, tartaric, malic, and citric acids,
which therefore fall in Group II. This discussion applies also
to low molecular weight amino acids where we note the additional
effect of salt formation. Salts not only of this type but of organic
acidic substances with inorganic bases and of organic bases with
mineral acids, with only a limited number of exceptions, are
insoluble in ether.
Space will not permit the discussion of additional solubility
data, but, in order to emphasize further the fact that the Solubility
Table need not be treated as a piece of memory work, an addi-
tional class exercise is assigned at the end of Chapter VIII.
CHAPTER III
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS
HYDROCARBONS AND THEIR OXYGEN AND HALOGEN
DERIVATIVES
The study of the elements of organic chemistry will have made
familiar the characteristic reactions of the common classes of
organic compounds, viz., the reactions of the carboxyl group, the
carbonyl group, the hydroxyl group, the nitro group, the amine
group, the aryl hydrocarbon group, etc. The following discus-
sion, together with the experimental work in Chapter IX, will
consist of a partial review of the facts that are furnished so plenti-
fully in a general course in organic chemistry. This review will
offer an opportunity for a reclassification of the information which
is unfortunately too often first studied in a memorizing fashion.
A systematic review from a different standpoint and a regrouping
of this information for the purposes of qualitative analysis is of
value as a general training for the chemist.
Qualitative organic analysis is possible because of the facts
of homology; all the members in a given homologous series
exhibit the same kind of chemical reactions, but they differ in the
velocity of reaction. Another important problem for considera-
tion is the effect of a given atom or group of atoms in modifying
the homologous tests of other groups simultaneously present in
the molecule. It is one of the functions of qualitative analysis
to teach some of this detailed information, particularly in connec-
tion with the actual laboratory study.
Most of the reactions to be discussed are adaptable to the
differentiation between various classes of possibilities within a
given solubility group; others possess value mainly in testing for
a limited number of individual compounds; a third type is adapted
mainly to quantitative work after a search has been limited to a
29
30 QUALITATIVE ORGANIC ANALYSIS
certain class; and a fourth type is useful after the identification
has been narrowed down to only a few individuals within a given
class when standardized reactions are required for the prepara-
tion of derivatives.
Not only is a familiarity with the reactions of organic chemis-
try required for the purposes of qualitative organic analysis, but
it is important also to know the conditions under which reactions
are applied and the limitations and interferences to which a test
may be subject under any set of given experimental conditions.
Such a knowledge must come primarily from the laboratory.
Behavior of Hydrocarbons Toward Cold Concentrated Sul-
furic Acid. — With the exception of the unsaturated members,
the hydrocarbons and their halogen derivatives will be found in
Solubility Group VI. Compounds of the define type will be
placed in Group V, although they do not dissolve in cold concen-
trated sulfuric acid readily, as is the case with oxygen derivatives
of the hydrocarbons. Compounds of the ethylene series react
with sulfuric acid in the following manner, the unsaturated carbon
atoms showing a preference for the acid radical in the following
order : Tertiary > secondary > primary.
CH3\ CHsv
>C=CH-CH3+HO-S02-OH -> >C-CH2-CH3
CH3/ CH3/ I
Isoamylene O-SO2OH
An alkyl sulfuric acid
The above reaction proceeds smoothly under suitable experi-
mental conditions, viz., proper temperature control and acid
concentration. The solution of alkyl sulfuric acid may be poured
into water, neutralized with excess alkali, and the corresponding
alcohol recovered by distillation. When an olefine is treated
with concentrated sulfuric acid without special precautions, as
in the usual solubility test, only a portion of the compound is
converted into a soluble alkyl sulfuric acid, the remaining portion
being polymerized to compounds of limited solubility in sulfuric
acid. The first step in such a polymerization may be repre-
sented thus:
CH3\ H2SO4 CH3\ /CH3
2 >C=CH2 > >CH-CH2CH=C<
CH3/ CUs"^ \CH
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 31
The mother substance, ethylene, is fau'ly resistant to polymeri-
zation but its homologs, beginning with propylene, are more
reactive. Amylene may be converted with 85 per cent sulfuric
acid at 0° into an almost quantitative yield of the corresponding
alkyl sulfuric acid but with less precaution it yields polymers con-
taining ten, fifteen, and twenty carbon atoms.
Problem 7. — When n-butyl alcohol is catalytically dehydrated it is con-
verted mainly into a mixture of n-butene-l and 2-methylpropene-l. Write
the equations to represent the reactions which take place when this gas
mixture is absorbed in sulfuric acid under conditions that do not lead to
polymerization.
Although paraffin hydrocarbons do not dissolve in sulfuric
acid, technical products such as petroleum ether, ligroin, gasolene,
kerosene, etc., which are often represented in text-books as typical
mixtures of paraffin hydrocarbons, exhibit considerable reaction
with sulfuric acid, due mainly to the presence of unsaturated
compounds. The amount of unsaturation in these technical
products has increased greatly during recent years, with the advent
of " cracking processes " for the production of lower-boiling frac-
tions from petroleum.
Aromatic hydrocarbons are insoluble in cold concentrated
sulfuric acid under the conditions chosen for the solubility tests.
A few individual members among the poly-methyl benzenes are
sulfonated slowly by cold concentrated sulfuric acid but the reac-
tion is not liable to be confused with the usual nonsulfonating
solubility test.
The Unsaturated Hydrocarbons. — Unsaturation in organic
compounds may be detected by a variety of addition reactions.
The addition of sulfuric acid to an ethylene double union has
already been illustrated. Other reagents which may be added
are halogens, halogen acids, ammonia and substituted ammonias,
diazomethane, ozone, hypohalites, nitrosylchloride, hydrogen
peroxide (H2O + O), tautomeric esters, organo-metallic com-
pounds, hydrogen, etc. Some of these addition reactions are of
great technical importance; others are of value in synthetical
work, particularly in connection with the determination of
structure of compounds.
Only two of the above addition reactions are convenient and
general enough for use in elementary qualitative work. These
two reactions are:
32 QUALITATIVE ORGANIC ANALYSIS
(a) Addition of halogen, usually of bromine, and
(6) Oxidation at the position of unsaturation by KMnO*
solution.
These reactions are typical not merely of unsaturated hydro-
carbons but of unsaturated linkages in general. In the presence
of certain negative groups, addition of bromine may be very slow
but in such cases the permanganate test will be found sufficiently
sensitive. Bromine may be decolorized, due to substitution
reactions, particularly among the phenols, aromatic amines, enols,
certain aldehydes, etc., but in such instances halogen acid may be
detected as a by-product. The above-mentioned types will also
respond to the permanganate test: these considerations are again
studied in connection with the actual experimental work of
Chapter IX. What inorganic compounds might be responsible
for decolorization of bromine and permanganate?
By means of bromine addition, we may differentiate the
unsaturated hydrocarbons from the saturated types.
CH.
CH
HC CH2 inCCk HCBr CH2
I I + 2Br2 > I I
CH2 CH2 CH2 CH2
CH2 CH3 CHsBr CH3
Terpene (dipentene) Tetrabromo addition product
of dipentene
CH3
K
in CCI4
-f Br2 > No reaction under same conditions.
CH3 CH3
p-Methyl isopropyl
benzene (cymene)
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 33
Problem 8. — Write the formulas for the products obtained from (a) the
addition of HBr to dipentene, (b) the addition of ozone to isoprene, (c) the
action of bromine water upon ethylene. J. Chem. Soc, 111, 242 (1917).
Bromine addition thus serves to differentiate between two
main groups of hydrocarbons; the reaction is adaptable also to
quantitative determinations (page 170) and as such is used exten-
sively in quantitative analysis of certain classes of organic com-
pounds. Only a few relatively unimportant hydrocarbons fail
to respond to this test. On the other hand, among the unsatu-
rated derivatives of hydrocarbons, there is considerable variation
in the ease of reaction with bromine.
TABLE XV
Differentiation between Hydrocarbons
Hydrocarbons +5 per cent Br2 in CCh at 0° to 20°
Molecular* quantities of Br2 decolor-
ized without production of a consid-
erable quantity of HBr.
Unsaturated hydrocarbons
Ethylene type
Acetylene type
B
No addition of Br2 in the cold and in
diffused light.
Hydrocarbons of saturated type
Paraffins, insolu-
ble in dimethyl
sulfate.
Not sulfonated by
HoS04-S03
Aromatics, solu-
ble in dimethyl
sulfate.
Sulfonated b y
H2S04-S03
* From the boiling-point of an unknown of a given type, the approximate number of
carbon atoms in the molecule may be predicted.
A differentiation between the two subclasses Ai and A2 is
seldom necessary since this is accomplished in connection with
the final identification of the individual compounds. A triple
union will usually add four atoms of bromine, but this is true also
of the diolefines. When both hydrogens of acetylene are replaced
by so-called negative groups (phenyl, carboxyl, etc.) only two atoms
of bromine are added. Ethylene derivatives containing such
negative groups add bromine rather slowly. (Example: Addi-
tion of Br2 to cinnamic acid.)
Oxidation with Potassium Permanganate. — The first effect of
permanganate upon an ethylene union probably consists in the
34 QUALITATIVE ORGANIC ANALYSIS
formation of an oxide which usually is detected only in the form
of its hydrolytic product.
O
R-CH=CH2 —^
R-CH— CH.
H2O
> R-CHOH-CH2OH
The resulting glycol, as such, would be comparatively stable
towards permanganate oxidation but, while in the process of
formation, it is readily oxidized past this stage to yield the cor-,
responding ketone and aldehyde groups, the final result being a
break between the two carbon atoms initially united through the
double union. The reaction has proven of great value as a means
of structure proof. Write the equations for the subsequent
steps in the oxidation of the above glycol.
Acetylene and its derivatives of the type R-C=C-H form organo-
metallic derivatives with ammoniacal cuprous chloride or with ammoniacal
silver nitrate. R-C=C-Ag and R-C=C-Cu. These precipitates although
explosive when dry, have been used for quantitative determinations. (Ber. 20,
3081 (1887).) An alcohohc silver nitrate solution precipitates a double salt.
R-C=CH+2AgN03 -* R-C^C-Ag-AgNOs+HNOs.
Titration of the nitric acid liberated furnishes a volumetric method of
analysis. 1
It has already been pointed out that ethylene derivatives may under
certain conditions add sulfuric acid to yield alkyl sulfuric acids from which
the corresponding alcohol may be recovered. The analogous reaction may
be applied to triple-bonded compounds, but the final product will be not an
alcohol but an aldehyde or ketone. Write equations to illustrate such a
reaction.
The Saturated Aliphatic Hydrocarbons. — For the differentia-
tion between the saturated aliphatic and aromatic hydrocarbons,
the reactions typical of the benzene nucleus are apphed. The
paraffin hydrocarbons are inert towards many of the reagents to
which the members of the aromatic series respond; the most
important reaction of the paraffins is substitution by halogens
and this reaction is not suitable for qualitative application. The
paraffin hydrocarbons usually met are the various fractions from
petroleum and in dealing with these products special provision
must be made for reaction due to the presence of not inconsider-
able quantities of unsaturated products.
1 Ann. chim. phys. (6) 15, 429 (1888); Ber. 25, 2249 (1892).
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 35
The cyclo-paraffins, with the exception of cyclopropane, which behaves
as an unsaturated hydrocarbon toward bromine (but not towards KMn04),
are similar in reactions to the normal paraffins. This class of compounds is
becoming of increasing importance because of the development of the cata-
lytic nickel method for the hydrogenation of aromatic hydrocarbons.
Problem 9. — Write the structural equation to illustrate the reaction
between cyclopropane and Br2.
Among the paraffin hydrocarbons, the greatest reactivity is
found among members which possess a tertiary carbon atom,
viz.:
R
R'^C-H
The hydrogen on the tertiary carbon may be appreciably attacked
by nitric acid, fuming sulfuric acid and by oxidizing agents. Sub-
stitution by halogens also takes place more readily. It is neces-
sary for this reason that the bromine titration of unsaturated com-
pounds be carried out at a low temperature and in the presence
of a diluent like carbon tetrachloride. For example, amylene,
which possesses a tertiary carbon, adds bromine almost quantita-
tively under the specified conditions. At a higher temperature,
the tertiary hydrogen may become involved in the reaction.
CHav cold CHsx
>CH-CH=CH2 + Bra > >CH-CHBr-CH2 Br
CH3/ ecu CH3/
Isoamylene 1, 2-dibromo-3-methyl butane
soam
Br2 CHss
heat CHs"
>CBr-CHBr-CH2Br + HBr
1, 2, 3-tribronio-3-methyl butane
Reactions of Aromatic Hydrocarbons. — The typical reactions
of aromatic hydrocarbons are:
1. Direct sulfonation,
2. Direct nitration,
3. Oxidation of side chains,
4. Controllable halogenation,
5. Reactivity in the Friedel and Crafts Reaction.
These reactions are typical also of many derivatives of aro-
matic hydrocarbons; in fact, the presence of certain substituents,
like the amine and phenolic groups, may facilitate substitution
into the benzene nucleus; on the other hand, certain other sub-
stituents, like the nitro and sulfonic acid groups, will cause sub-
36
QUALITATIVE ORGANIC ANALYSIS
stitution to take place with more difficulty. Nevertheless, among
substitution products of aromatic hydrocarbons, these reactions
are relatively unimportant from the standpoint of classification,
but they are especially valuable for the preparation of derivatives.
Application of direct sulfonation is the most convenient
reaction for the differentiation of aromatic hydrocarbons from the
saturated aliphatic type. The various aromatic hydrocarbons
differ considerably in the ease of reaction with sulfuric acid;
some members sulfonate slowly with concentrated (95 per cent)
sulfuric acid without heating, others require concentrated acid
with heating, while still others require fuming sulfuric acid occa-
sionally with heating. The most convenient reagent for the dif-
ferentiation is fuming sulfuric acid containing 20 per cent of the
anhydride. The sign of reaction is the generation of heat and the
gradual but complete solution of the hydrocarbon without exces-
sive charring. Impure paraffin hydrocarbons may show consid-
erable charring due to the presence of unsaturated compounds,
but the main portion of the product is not attacked.
Benzene reacts extremely slowly even with hot concentrated
H2SO4. In fuming sulfuric acid (H2S04-S03), it dissolves readily
and completely, considerable heat being liberated. The second
sulfonic acid group enters less readily and the third group only
with great difficulty.
C6H5-S=0 + H2O
\0H
Benzene sulfonic acid /DO3XI
SO3H
SO,
CeHg + H2SO4
CeHs-CHs + HO-SO2-OH
SO3H
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 37
Toluene sulfonates more readily than benzene, while o- and
w-xylene and mesitylene may be slowly sulfonated with 95 per
cent H2SO4, even without heating. Para derivatives, such as
p-xylene, dissolve less readily (separation of the xylenes), while
p-dihalogen benzenes require 20 per cent fuming sulfuric acid and
heating to 100° to 120° for sulfonation. Substitution in naph-
thalene takes place more readily than in benzene and therefore
concentrated H2SO4 may be used.
.SO3H
+H2SO4
Mainly naphthalene-ot-
~T" -tL2Vj sulfonic acid
SO3H
Mainly (85 %) naph-
thalene-/3-8ulfonic acid
Problem 10. — In the sulfonation of benzene with H2S04-S03, a trace of
diphenyl sulfone is formed. Write the equation for the reaction. Separate
a mixture of o- and p-chlorotoluene by means of sulfonation reactions.
Although sulfonation is an important "classification reaction," it is of
less importance as a "characterizing reaction." To be sure, the sulfonic
acids may be isolated as the sodium salts, the latter converted (after drying)
into the acyl chlorides and characterized either as such or in the form of
the amides. More direct characterization methods are usually available.
A few sulfonic acids may be isolated as such, but in general they are difficult
to isolate because of their extreme solubility in water.
Direct nitration, either with fuming HNO3 or with a nitrating mixture
containing equal volumes of concentrated HNO3 (1.4 sp. gr.) and con-
centrated H2SO4, is sometimes used for the differentiation between saturated
aliphatic and aromatic hydrocarbons. Its disadvantage consists in the fact
that the resultant nitration product often possesses a solubility behavior
similar to that of the original unknown. Nitration is of greater value as a
reaction for the preparation of derivatives.
Oxidation of side-chains, with the resultant formation of carboxyl groups,
is another typical reaction of aromatic hydrocarbons and of many of their
derivatives. This reaction is of minor importance for the purposes of classi-
fication but again it is of great value in the preparation of derivatives. It
will therefore be discussed in Chapter X.
Problem 11. — Review the rules governing the positions taken by sub-
stituting groups introduced into the benzene nucleus. Place the groups
NO2, OH, CI, Br, NH:, NH-COCHa, SO.,H, CH3, OC2H5 and CO2H approx-
imately in the order of their directing abihty. Cf. Annual Reports 15, 75
(1918).
38 QUALITATIVE ORGANIC ANALYSIS
Problem 12. — What organic acid is formed when
CeH/
CH2-CH3 (1)
CH2-CH2-CH3 (2;
is oxidized with neutral or alkaline permanganate?
Differentiation between Aromatic and Paraffin Hydrocarbons.
— Differentiation between these two classes of hydrocarbons by
means of the sulfonation test has already been discussed above.
To some extent, sulfonation may be applied also when we are
dealing with halogen derivatives of hydrocarbons, although usually
considerable decomposition takes place with the evolution of
halogen acid in the case of the chlorides and bromides and of free
iodine in the case of iodides. Halogen attached directly to the
benzene nucleus is stable toward sulfonation.
A more convenient method for differentiation between the aro-
matic and paraffin hydrocarbons is the dimethyl sulfate solubility
test (page 135). The paraffin hydrocarbons do not dissolve
appreciably in this reagent, whereas aromatic hydrocarbons in
general dissolve in all proportions, due probably to the formation
of an addition product between the ester and the aromatic nucleus.
The aromatic hydrocarbons may be recovered from dimethyl
sulfate by saponifying the latter with dilute alkali. This method
of differentiation does not extend to the halogen derivatives of these
hydrocarbons.
The use of dimethyl sulfate^ is illustrated in the laboratory
work. Special precautions must be taken in the use of this reagent
since it is reported to be extremely toxic.
The Reactivities of Organic Halogen Compounds. — Halogen
compounds of a given type but differing in the nature of the halo-
gen, possess the following order of reactivity toward the usual
organic laboratory reagents: I>Br>Cl. Among the halogen
substitution products of paraffin hydrocarbons, the reactivity
for a given halogen united to tertiary, secondary, or primary
carbon atoms respectively, is in the order mentioned, the tertiary
halogen compound possessing the greatest mobility. Halogen
compounds in which the halogen (X) is united directly to an
unsaturated carbon atom of the type C = C, possess increased
1 Chem. Ind. 23, 559 (1900).
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 39
stability. Unsaturation on the /S-carbon gives increased activity.
Substitution by oxygen on the a-carbon increases the activity.
CH3-CH=CHX is more stable than CH3-CH2CH2X or
CH2=CH— CH2X.
/CH3
• '^ ^^
C6H4\' is more stable than C6H5CH2X. ^.^.--^^y Qp flj^
} are very reactive. m n-n iian SS^^^
R-O-CH2X J
Carboxylic acids that are aliphatic in nature and which possess
a halogen on the gamma carbon exhibit greater reactivity toward
elimination of HX (lactone formation) than do the a and /3 sub-
stituted acids.
H ^O Na2C03Sorn H
CH3-C -CH2CH2C^OH > CH3-C-CH2-CH2-C=0
Br i_0 ^
Lactone or inner ester
The usual tests employed for determining the relative reac-
tivities of halogen compounds are:
(a) Reactivity towards tertiary amines,
(6) Reactivity towards alcoholic KOH,
(c) Reactivity towards alcoholic AgNOs.
The reactions of organic halogen compounds with tertiary
amines, resulting in the formation of quaternary ammonium
compounds, has been used extensively for quantitative measure-
^lents of reactivity the degree of which is usually expressed in the
form of a velocity constant. Since the ammonium derivative
formed in the reaction possesses ionizable halogen, the amount of
reaction up to any given time may be determined conveniently
by volumetric methods.
Methods (6) and (c) are used more often in connection with
qualitative work in the laboratory. A small amount (about 0.2 g.)
40 QUALITATIVE ORGANIC ANALYSIS
of the organic compound is dissolved in a few cc. of a 5 per cent
solution of KOH in aldehyde-free ethyl alcohol. The mixture
is boiled gently for about a minute and is then diluted with several
volumes of water and acidified with HNO3. Any organic com-
pound separating upon dilution must be removed by filtration,
lonizable halogen in the aqueous solution is then tested for by
means of the usual aqueous AgNOs reagent.
The alcoholic AgNOs test is assigned in Chapter IX in con-
nection with the laboratory work. It may be applied more rapidly
than the alcoholic potash test and is almost as satisfactory.
A saturated solution of AgNOs in absolute alcohol is used as a
reagent, the alcohol serving as a common solvent for both the
AgNOs and the organic compound to be tested. The test is not
applicable to unsaturated compounds, some of w^hich may form
insoluble addition products with AgNOs in alcoholic solution;
neither should it be applied to compounds of the salt type. Cer-
tain acidic substances may produce a precipitate of an insoluble
silver salt which might be mistaken for silver halide. Care must
be taken therefore in applying the test to substances of this char-
acter. Water-soluble substances containing halogen should be
tested with aqueous AgNOs after acidification with HNO3.
But here also precautions are necessary similar to those taken
with the alcoholic solution.
The organic halogen compounds may be placed in four groups from the
standpoint of their reactivity towards AgNOv
(1) Water-soluble compounds containing ionizable halogen, or com-
pounds such as acid halides of low molecular weight, which react
readily with water to form ionizable halogen compounds, will
react instantaneously, even with aqueous AgNOs.
(2) Water-insoluble acyl halides, tertiary halogen compounds, etc.,
react instantaneously with alcoholic AgNOs.
(3) Primary and secondary halogen compounds in the aliphatic series
or aromatic compounds containing halogen in the side-chain,
react slowly with alcoholic AgNOs but fairly rapidly on heating.
Some chlorine derivatives are exceptions to this rule.
(4) Aromatic halogen compounds containing halogen in the ring
do not react even upon heating. Compounds of this type sub-
stituted by a nitro group in the ortho position, however, possess
considerable activity.
The Friedel and Crafts Reaction is a method of introducing a side-chain
into the benzene nucleus by treating an aromatic hydrocarbon with a reactive
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 41
halogen compound in the presence of anhydrous aluminum chloride. The
reaction is sometimes applied in order to differentiate between certain classes
of halogen compounds. It is occasionally also used to differentiate between
paraffin and aromatic hydrocarbons. The main objection to the test is that
an appreciable quantity of pure material is required.
Problem 13. — Explain exactly how the Friedel and Crafts Reaction may
be applied in the laboratory in order to (a) differentiate cyclohexane from
benzene, and (b) benzyl chloride from o-chlorotoluene.
The Acyl Chlorides. — These compounds are chiefly of value as
reagents for the testing of amines, alcohols, and phenols. When
an unknown containing a very reactive halogen atom is suspected
of being an acyl halide, the usual experimental conditions are
reversed and a known amine is used as a reagent for the unknown.
Problem 14. — Write the reaction which takes place between p-toluene
sulfonj'l chloride and aqueous NH3. What is formed when the reaction
product is treated with a slightly alkaline solution containing one mole of
NaOCl?
The Indifferent Oxygen Derivatives of Hydrocarbons: Alde-
hydes, Ketones, Esters, Anhydrides, Alcohols, and Ethers. —
With the exception of a relatively small number of members of
low molecular weight (Group I), these compounds fall into Solu-
bility Group V. Contrary to the usual assumption, relatively
few members from the above series are decomposed by cold con-
centrated sulfuric acid. Solubility in sulfuric acid without
decomposition is by no means peculiar to the ethers. Differentia-
tion between Groups V and VI, however, is not limited to solubility
without decomposition; in fact, we have already discussed the
behavior of the unsaturated hydrocarbons in this respect. Solu-
bility with discoloration and partial polymerization will be noted
especially with aliphatic aldehydes; ethers of the acetal type will
readily hydrolyze; and marked decomposition will be noted with
benzyl alcohol and its derivatives, a decomposition which may
possibly be typical of many aromatic compounds with the
— CH2OH side-chain. The complete decomposition of a product
of the latter type with the production of solid products insoluble
in concentrated H2SO4 must be accepted as evidence that the
unknown is not a hydrocarbon.
In testing for the compounds in Group V, the following order
is preferable:
42
QUALITATIVE ORGANIC ANALYSIS
TABLE XVI
Solubility Group V, Aldehydks, Ketones, Esters (Anhydrides),
Alcohols, Ethers, etc. Apply the Phenylhydrazine Test
Positive reaction.
Aldehyde or ke-
tone. Apply tests
to differentiate
(Anhydrides will inter-
fere. See page 45.)
Negative test.
Esters (anhydrides), alcohols, ethers, unsaturated HC.
Apply saponification test
Positive reaction. Es-
ters and anhydrides
Negative reaction. Alcohols,
ethers, unsaturated HC. Ap-
ply acyl halide test
Po.sitive reac-
tion. Alcohols
Negative reac-
tion. Ethers
and unsatu-
rated HC
Both aldehydes and ketones possess the carbonyl group -C —
and their most important reactions are therefore the typical
reactions of this group. The speed of reaction of the carbonyl
group, and, to some extent also the kind of reaction, is dependent
upon the groups united to the carbonyl. In aldehydes, R-C — H,
the carbonyl group is united to a hj'drogen atom, whereas in
ketones R-C — R', the aldehyde hydrogen is replaced by a radical
of higher molecular weight. In additive reactions, the aldehydes
will therefore show a greater reaction velocity; individual ketones
will exhibit decreased reaction velocity with increase in molecular
weight of the radical R^ Differentiation between aldehydes and
ketones may be based upon this difference in the ease of reaction.
//^ .
Since the hydrogen of the -C — H is readily oxidized to hydroxjd,
another differentiation between aldehydes and ketones is found
in differences in the ease of oxidation.
The carbonyl group increases the mobility of the hydrogens on adjacent
carbon atoms. For this reason, substitution by halogens takes place more
readily with these classes of compounds than with the hydrocarbons.
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 43
O
II /OH Br2
R-C-CH2-R :;± R-C=CH-R >
Enolic form
of ketone
/OH
R-C— CHBr-R
I
Br
R-C— CHBr-R+HX
A methylene (CH2) group adjacent to the carbonyl group is often spoken
of as a reactive methylene. It takes part more readily in condensation,
oxidation, halogenation and other reactions than does the normal methylene
group in hydrocarbons.
A methylene group adjacent to two carbonyl groups exhibits unusual
reactivity, due to an increase in the amount of enolization. Such com-
pounds form sodium salts with alcoholic sodium ethylate and are of con-
siderable importance in synthetical work. Some of these enols may behave
toward alkali treatment in a manner suggestive of the saponification of esters.
O O
II II /OH ^O NaOHsol'n
CH3-C-CH2-C-CH3 ;=i CH3-C=CH-C— CHs >
Acetyl acetone -l-heat
o
II
CH3-C— ONa +CH3-C-CH3
./^
Although the various reactions just discussed are seldom used for classi-
fication purposes in elementary analytical work, they are of importance in
connection with possible interference with the usual tests.
Problem 15. — Write the reactions for (a) the ketone spUtting of aceto-
acetic ester, and (6) the acid splitting of the same ester.
Problem 16. — Upon saponifying an ester with concentrated alkali, an
alcohol and an acid are obtained. Which classes of aldehydes also yield
acids and alcohols under similar treatment? Write the equations.
Other common classes of compounds which, according to the
Hnking theory, possess carbonyl groups, are carboxylic acids,
esters, amides, acyl halides, etc. These groups, however, do not
exhibit the typical carbonyl condensation reactions.
General Test for Aldehydes and Ketones. — Phenylhydrazine
reacts with both aldehydes and ketones to yield phenylhydra-
zones. The reaction is catalyzed by the presence of a weak acid
like acetic, but strong acids may prevent the reaction; for
example, phenylhydrazine hydrochloride may not react unless
an equivalent amount of sodium acetate is added. The sign of
44 QUALITATIVE ORGANIC ANALYSIS
reaction is the formation of a sparingly soluble phenylhydrazone,
which is insufficiently basic to dissolve in dilute acid.
When a clear solution of phenylhydrazine in dilute acetic acid
is added to a dilute aqueous solution of an aldehyde or ketone of
low molecular weight, an immediate and almost quantitative
precipitation of the corresponding phenylhydrazone is noted.
For water insoluble carbonyL compounds, a modified procedure is
proposed (Chapter IX). When the phenylhydrazone of an
unknown is found to be a solid, it may be recrystallized and used
as a derivative.
H
R\ H\ I y V dilute acetic acid
C=0 + ^N-N— < > >
H(RO
H H
R\ /OH I I .
H(RO
H
R\ I
\C=N-N
H(R')
>
Intermediate product Phenylhydrazone of the
aldehyde or ketone
This reaction has been adapted to quantitative volumetric
work^ as is also the case with certain other condensation reactions,
particularly the reaction with hydroxylamine.^
In addition to the condensation with phenylhydrazine, the
aldehydes and ketones undergo analogous reactions with other
substituted ammonias. This topic will be discussed further in
connection with the preparation of derivatives, in Chapter X.
Discussion of the Phenylhydrazine Reaction. — The dilute acetic acid
solution of phenyldrazine should be prepared just before using. After it
has been allowed to stand even at room temperature for several days, an
appreciable amount of the sparingly soluble acetyl derivatives of phenyl-
hydrazine will have formed. In general, the phenylhydrazones are much
less soluble in various solvents than are the corresponding aldehydes and
ketones. A convenient method of applying the test to water insoluble
compounds therefore consists in dissolving the carbonyl compound in a small
amount of alcohol and adding water drop by drop until the solution is exactly
at the saturation point. An amount of pure liquid phenylhydrazine equal
to that of the unknown is then added. In the case of most aldehydes, an
1 Monatsh. 13, 299 (1892). ' - « Analyst 34, 14 (1909).
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 45
almost immediate precipitation of the phenylhydrazone takes place, due
to the fact that it is less soluble in the dilute alcohol than is the aldehyde.
If no precipitation takes place within one minute's time, one drop of glacial
acetic acid is added in order to catalyze the reaction.
The various ketones differ greatly in their speeds of reaction with phenyl-
hydrazine, some precipitating after a few seconds, others after several
minutes, whereas members of very high molecular weight may require a
considerably longer time. The rapid reaction of most aldehydes without the
addition of a drop of acetic acid to act as a catalytic agent may possibly be
explained by the fact that many of the aldehydes contain a trace of acid as
an impurity. Aldehydes of special purity show slower reactions, corre-
sponding more closely to the ketone reaction.
A number of salts of phenylhydrazine are only sparingly soluble in water;
this is true of the oxalate, sulfate, phosphate, etc. It is therefore important
that this be kept in mind when phenylhydrazine is used in testing for the
presence of aldehydes or ketones in aqueous solutions which might contain
also other substances.
Among the esters, a few members, for example, methyl oxalate, may be
sufficiently reactive to combine with the reagent to form an acyl derivative,
the precipitation of which might be confused with the test for the carbonyl
group. This is true also of the anhydrides.
Phenylhydrazine is important in testing certain sugars (Chapter V).
In addition to the phenylhydrazine test, many other reactions may be
adapted, with suitable limitations, as tests for the carbonyl group. In
general, these reactions are not as convenient and satisfactory as the test out-
lined above. The formation of addition products with sodium acid sulfite is not
as general as is often suggested in text-books. Aldehydes and low molecular
weight ketones react readily but the higher ketones and particularly aromatic
ketones show very little reaction, particularly when the ketone group is
adjacent to the aromatic nucleus. The reaction is almost as satisfactory for
differentiation between aldehydes and ketones as for a general test, and
somewhat unsatisfactory for either purpose. The sulfite addition products
are sometimes quite soluble in water. ^
.0 /OH
R-Cf + NaHSOs -^ R-C^O-SO.Na
^H \H
The reaction is often of value in purifying aldehydes and ketones. The
organic compound may be recovered by treatment with either dilute acid or
alkali (Na2C03). A common source of error in applying the test to an
alcoholic solution of an unknown consists in a precipitation of the sodium
bisulfite itself, due to its lower solubihty in alcohol.
Problem 17. — Write structural equations for the following reactions:
(a) Benzaldehyde and concentrated alkali in the Cannizzaro reaction,
(6) formaldehyde + ethyl alcohol in the presence of a small quantity of dry
HCl, (c) a ketone -1- aqueous HCN, {d) acetone H-an aqueous solution of
46 QUALITATIVE ORGANIC ANALYSIS
NH4CI and KCN, (e) acetaldehyde+NHs in dry ether, (/) benzaldehyde or
furfural + aqueous NH3, (g) benzaldehyde + aniline (alcoholic solution), (h)
magnesium ethyl bromide and n-heptanal.
The Differentiation between Aldehydes and Ketones. —
(a) The Ammoniacal Silver Nitrate Test. Aldehydes are readily
oxidized with ammoniacal silver nitrate solution, whereas ketones
are more stable.
O /in sol'n as \ ^Q
R-Cr + AgsOl Ag(NH3).0Hl -^ R-C^0-NH4+ 2Ag j
(b) The Fuchsin Aldehyde Test. — Aldehydes restore color to
Fuchsin Aldehyde Reagent whereas ketones do not. The reagent
is a dilute solution of rosaniline or fuchsin hydrochloride (magenta)
that has been decolorized by sulfur dioxide.
Rosaniline HCI+2H2SO3
Crimson color. _^ (H2N • C6H4)2 : C • C6H4 • NH • SO2H
I
S03H
Colorless-
The aldehyde reverses this reaction due to a removal of H2SO3
from the methane carbon and a regeneration of the quinoid hnk-
age. The restored color is not identical with the original fuchsin
color but possesses a distinct bluish tinge. This is due to a reac-
tion between the aldehyde and amino groups. The recently pro-
posed formula for the aldehyde-dye,
(R-CHOHOSONH-CgH4)2 : C : C6H4 : NH
(Ber. 54, 2534) is still open to question.
In general those reagents which remove sulfurous acid will
restore the fuchsin color. This is true of organic amines, inorganic
alkahs, and even of certain hydrolysable salts. Heating the
reagent restores the color due to the dissociation of the fuchsin-
sulfite compound. Although the restored color lacks the typical
bluish tinge produced by aldehydes, it is always advisable to
apply the test in the cold and to bear in mind the possible inter-
ferences.
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 47
General Test for Esters and Anhydrides. — When a compound
responds to a test for an aldehyde or ketone, other reactive groups
may of course be present also. If such should be the case, evi-
dence will be found in connection with the subsequent tests, and
particularly in connection with the physical constants of the
unknown and its derivatives. Consultation of tables of physical
constants before applying class reactions is unjustifiable and liable
to cause unnecessary work because it is apt to be misleading.
On the other hand, after a typical group has been located, then
physical constants will be of value in indicating other possible
groups to be tested for (with due consideration for complications
caused by the simultaneous presence of several groups).
The general test for esters (including lactones) and anhydrides
is saponification with alkali. Ethers will remain unaffected under
the experimental conditions chosen, but aldehydes may be
decomposed. See Problem 17.
Problem 18. — Write structural equations to illustrate the saponification
of (a) phenyl salicylate, (6) benzoic anhydride, and (c) nitroglycerol.
Differentiation between Esters and Anhydrides. — Three com-
mon classes of compounds contain an oxygen atom uniting two
carbon atoms, viz.:
R-CH2-O-CH2-R Ether,
R-C^O-CHsR Ester, and
O O
II II
R-C— 0-C-R Anhydride.
The ethers are stable towards the usual alkali treatment. In
the esters, the -C— structure has greatly weakened the -C-O-C
linkage. It is logical therefore to expect that a compound pos-
O O
II II
sessing two carbonyl groups joined through oxygen, -C — 0-C-,
will be unusually susceptible to hydrolysis. This is true, and we
48 QUALITATIVE ORGANIC ANALYSIS
may therefore differentiate the anhydrides from the esters by
(a) the great susceptibility of the former type to undergo hydrol-
ysis and (6) the fact that the hydrolysis of the former produces
no alcohol as a by-product. Very often the hydrolysis of anhy-
drides may be carried out in the cold with dilute alkali. Esters
usually require refiuxing with strong alkah, sometimes in alco-
holic solution.
It should be remembered, however, that some esters of polycarboxylic
acids, such as oxalates and malonates are hydrolyzed very readily. Methyl
and ethyl formate, methyl acetate, etc., are also rapidly hydrolyzed in
aqueous solution but the boiling-points (below 130°) of the latter compounds
exclude the possibility of anhydrides. Explain.
The acyl haUdes may be considered as mixed anhydrides; they are,
however, differentiated from the usual anhydride in connection with the
elementary analysis.
A logical method for differentiating an anhydride from an ester is based
upon the fact that the anhydride can react with an alcohol to produce one
mole of ester and one mole of free acid. An anhydride of a dicarboxylic acid
will react to produce an acid ester.
O Q
c/ /\ /C^O-R
O + ROH
C^^ \/ \C^OH
o
Additional reactions of anhydrides are discussed in the following chapter
in connection with the tests for amines. The use of such reactions is
reversible, and amines may be used as reagents to test for anhydrides.
Differentiation between Alcohols and Ethers. — Alcohols may
be differentiated from ethers by the usual reactions of the hydroxy!
group, viz.:
(1) Reaction with metallic sodium,
(2) Reaction with acyl haUdes and anhydrides,
(a) Acetyl chloride,
(6) Benzoyl chloride,
(c) Other acyl halides,
(d) Anhydrides,
(3) Reaction with phenyl isocyanate.
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 49
The most common interfering substance is water. The enoHc
forms of aldehydes, ketones, and tautomeric esters also possess
-OH groups and will respond to some of these tests, particularly
to the metallic sodium test. It is partly for this reason that tests
for aldehydes, ketones, esters, etc., precede tests for alcohols.
^O /OH /ONa
/C^OR ^C^O-R Na ^C^OR
CH2< //O ^ HCf /O > H-Cf /O + H
\C^OR \C^O-R \C^OR
O
II /OH Na /ONa
CH3-C-CH3 ^ CH3-C^CH2 > CHs-C^CHa + H
/O 2Na
'y (
2CH3-C^OR
trace of alcohol as impurity
/ONa /O
CH3-C=C— C^OR + R-ONa + H2
H
The Use of Acyl Halides or Anhydrides is more satisfactory
than that of metallic sodium since the enolic forms of most alde-
hydes and ketones are not detected by these reagents.
R'-O-H + R-C^Cl -> R-C^O-R' + HCl
^0
R-O-R + R-C^Cl -^ No reaction if pure.
H-O-H + R-C^Cl -^ R-C^OH + HCl
One cc. of the unknown is treated cautiously with 1 cc. of
acetyl chloride. The signs of reaction are the evolution of heat,
the liberation of hydrochloric acid gas, and the formation of an
ester. The fact that esterification has taken place is indicated by
the odor of the reaction product after it has been poured into a
small amount of water to remove the excess of acetyl chloride;
a mere trace of alcohol as impurity in an ether might also be respon-
50
QUALITATIVE ORGANIC ANALYSIS
sible, however, for an ester odor. Change in solubihty is another
sign of reaction, as is indicated in Table XVII below.
TABLE XVII
Alcohol
Solubility of the
alcohol. Grams per
100 grams of H2O
Solubility of the
acetyl derivative.
Grams per 100 grams
of H2O
Ethyl
GO
00
10
9
2.5
8.0
Propyl
1.5
Isobutyl
0.7
n-Butyl
Isoamyl
0.6
0.2
A change in other physical properties, such as conversion of a
liquid unknown to a solid derivative, is another indication of
reaction. In special instances, the reaction product may be
isolated, washed free from acids, and the presence of the acetyl
group determined by saponification tests (page 140).
In the acylation reaction, primary and secondary alcohols behave in the
normal manner but tertiary alcohols often react to produce halogen deriva-
tives of hydrocarbons.
R'-^C-OH + CHa-C^Cl
R'
R
7'
y/\
o
R'-^C-Cl + CHa-C^OH
R"/
Benzoyl chloride possesses the advantage over acetyl chloride in that it is
only very slowly decomposed in cold water and therefore it may be used
in detecting alcohols even in aqueous solution, since the -OH group in the
alcohol reacts much more rapidly with the acyl chloride than does the -OH
group of water. The reaction is usually carried out in aqueous solution
containing sufficient alkali to decompose any e.xcess of benzoyl chloride into
the water-soluble benzoate. The benzoyl esters formed are insoluble in
water.
The substance most frequently interfering with the acetyl chloride test
is water. The -OH groups of most phenols act similarly to the alcoholic
-OH group. Ammonia, primary amines, and secondary amines react
unusually readily with the acyl halides and anhydrides and therefore special
precautions must be used in applying the test to nitrogenous compounds.
Phenylisocyanaie Test. — Alcohols and phenols react with isocyanates in
the manner indicated by the subsequent equations, the latter the more
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 51
readily. One of the common reagents used in organic laboratory work is
phenylisocyanate.
O
— N=C=0 + H-0-
N=C=0 + H2O
H
— NH + CO2
H II , .
C6H5-N=C=0
\/
The presence of moisture interferes with the reaction and the reagent is
also sensitive to ammonia and to the amines. With a few exceptions, the
usual acyl anhydrides do not react with the enols, whereas phenylisocyanate
has found considerable application as a reagent to detect the enolic forms of
certain tautomeric compounds.
The Differentiation between Primary, Secondary and Tertiary Alcohols. —
Primary, secondary and tertiary alcohols differ greatly in their reaction
velocities in esterification with acetic acid; these velocities^ are approximately
as follows: I : II : III : : 40 : 20 : 2. The amount of esterification which has
taken place in a given time under standardized conditions therefore is of
considerable value in differentiating between the various classes of alcohols.
For general qualitative work, it is scarcely adaptable, since several hours
are required for the determination.
The Hydrobromic Acid Method. — Most tertiary alcohols react very
quickly with 48 per cent hydrobromic acid to give a good yield of alkyl
bromide. Secondary alcohols react fairly rapidly when they are refluxed
with the hydrobromic acid solution, whereas primary alcohols react slowly
upon refluxing but quite rapidly when one mole of H2SO4 is used for every
two moles of hydrobromic acid.-
The Phthalic Anhydride Test. — Phthalic anhydride reacts with primary
alcohols when a benzene solution of the two compounds is refluxed. Secondary
alcohols react less readily and it is usually necessary to heat the mixture
of anhydride and alcohol to a temperature of from 100° to 120°. Tertiary
alcohols do not react.
The Victor Meyer Method is adaptable mainly to alcohols of low molecular
weight. These alcohols are converted into the corresponding nitro com-
pounds through the iodides. Primary, secondary and tertiary nitro com-
pounds may then be easily differentiated. The tertiary nitro compound
does not dissolve in dilute alkali, while the other two members are alkali-
soluble, due to their ability to exist in an aci-form. The last two may be
1 Weyl, Methoden, Part II, p. 756 (1911).
2 J. Am. Chem. Soc. 42, 299 (1920).
52 QUALITATIVE ORGANIC ANALYSIS
differentiated by their action towards nitrous acid. The secondary nitro
compound forms a nitroso derivative which is no longer soluble in alkali
and which usually possesses a characteristic color. The primary nitro
compound forms a nitroso compound which is alkali-soluble because of its
ability to exist in the isomeric oxime form. Although the Victor Meyer
test is rather limited in its application to alcohols, the same reactions are
of value for the differentiation between I, II, and III alkyl iodides and I,
II and III aliphatic nitro compounds. For this reason it deserves mention
here.
Problem 19. — Write equations to illustrate the reactions involved in the
Victor Meyer method for the differentiation between I, II and III alcohols.
Weyl, p. 753 (1911).
Neutral Compounds of Group I. — Aldehydes, ketones, and
alcohols of low molecular weight, together with a few esters, are
found in Solubility Group I, since they are soluble in water and
also in ether. They will usually, but not always, be met as liquids.
When a substance is located in Group I, the aqueous solution of
the unknown is immediately tested for acidity, so as to differen-
tiate the neutral from the acidic substances. If the aqueous
solution is acid to litmus, a portion of the unknown, about 0.2 g., is
titrated with 0.1 N. alkali, using phenolphthalein as an indicator.
Small amounts of acid, often inorganic, may be present as impuri-
ties and it is important therefore to know approximately the
amount of acidity,
A few esters in Group I will produce acid reactions and this is
true of all the water-soluble anhydrides. Upon titration, the
former will be neutralized gradually, whereas the water-soluble
anhydrides are saponified more rapidly.
Problem 20. — How many cc. of 0.1 N alkali are required to neutralize
(a) 0.1 g. of propionic acid, (b) 0.1 g. succinic anhydride, (c) 0.1 g. aniline
sulfate, and (d) 0.1 g. methyl oxalate assuming that only one ester group is
rapidly saponified? Phenolphthalein is used as the indicator.
. The discussion of reactions of neutral oxygen compounds and
the order of applying tests in Group V applies directly to the
corresponding compounds in Group I, variations being in degree
only, since the low molecular weight compounds differ mainly in
possessing greater rates of reaction towards the reagent employed.
The low molecular weight aldehydes and ketones will react with
phenylhydrazine almost instantaneously, whereas a ketone, like
O
II
benzophenone, CgHs-C-CoHs, reacts comparatively slowly.
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 53
Aldehydes of Group I react unusually rapidly with ammoni-
acal silver nitrate and with fuchsin aldehyde reagent. Similarly,
esters and anhydrides undergo hydrolysis more readily than the
corresponding classes in Group V, a reaction which is aided partly,
of course, by the fact that the compounds are water-soluble.
Several esters in this group react so readily with water, ammonia,
and the amines, that they might be mistaken for anhydrides by
the uninitiated. However, they yield both acids and alcohols
upon hydrolysis.
C^OCHs
C^OCHs
+ 2NH3
C^NH2
C^NHa
C^OCHa
H
/-
+2 N-.
O H \
C^OCHs
C^— -N-
C
/
OH
-N-
The Ipdoform Test. — Compounds in Group I which possess
the aceto group \CH3-C— / united to either carbon or hydro-
gen, or compounds which are oxidized to this structure under the
conditions of the experiment, will respond to the iodoform test.
(Exp. 10, Chapter IX.) A positive test consists in the precipi-
tation of iodoform when a dilute (5 per cent) solution of the
unknown is treated with NaOI solution, either in the cold or upon
warming to 60° during a few minutes time. The reactions involved
are as follows:
^O /OH NaOI
C H3— C — CH3
/OH
CH3-C=CH2 -
/OH
CHg-C^CHoI
I
ONa
O
II
CH3-C-CH2I + NaOH
Enolization of the ketone and addition of NaOI again takes
place and results in the formation of:
CHs-C^Cei
\I
54 QUALITATIVE ORGANIC ANALYSIS
a compound unstable in the presence of alkali.
CH3-C^C^I + NaOH -^ CHs-C^ONa + CHI3
\I
Problem 21. — Classify the following compounds into two groups, (a)
those which will respond to the iodoform test, and (6) those which will fail
to yield iodoform under the usual experimental conditions:
/ (1) acetone, — (5) acetic acid, (9) propionaldehyde,
(2) methyl alcohol, (6) isobutyl alcohol, (10) levulinic acid,
^ (3) ethyl alcohol, (7) secondary butyl al- (11) pyruvic acid,
(4) propyl and isopropyl cohol — (12) acetoacetic ester,
alcohols, • — (8) acetaldehyde, (13) diethyl ether.
Acidic Compounds. — The main acidic compounds containing
only the elements C, H, and O are the carboxylic acids and the
phenols. These compounds are found mainly in Group IV,
although the water-soluble members will be found divided between
Groups I and II. A relatively small number of phenols belong
to the alkali-insoluble class and are liable to be classified in Group
V (see Chapter II, problem 3).
The majority of phenols are feebly acidic in comparison with
the carboxylic acids; the latter may be titrated quantitatively
in aqueous solution using phenolphthalein as an indicator, but
this is not true of the phenols. Methods of classification, such as
the following, have been proposed, but are so obviously open to
exceptions that a brief discussion is necessary.
[ Soluble in alkah but precipi-
tated upon saturating the
(1) Phenols \ solution with carbon di-
oxide.
Insoluble in NaHCOs solution.
(2) Weak Carboxylic Acids f Soluble in NaHCOs solution
(not negatively substi- \ but insoluble in sodium for-
tuted) i mate solution.
(3) Strong Carboxylic Acids,
particularly dicarbox-
ylic acids, nitro car-
boxylic acids, etc
Sulfonic Acids, etc
The above classification may lead to error because it does not
take into consideration the water-solubility of the individual
Soluble in sodium formate
solution.
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 55
compounds. The partition of a base between two acids is con-
trolled not only by the respective strengths of the acids, but also
by their concentrations. In substances very sparingly soluble in
water, the concentration of the dissolved substance is greatly
limited and this is the reason that certain acids, although strong
acids, are precipitated by carbon dioxide; on the other hand,
many phenols are sufficiently soluble in water to fail to precipi-
tate with carbon dioxide. This method of differentiation must
be used, therefore, with proper appreciation of its limitations.
Certain other classes of acidic compounds, such as imides,
sulfonamides, etc., when only sparingly soluble in water, can be
precipitated from their sodium salts by means of carbon dioxide.
Differentiation between Phenols and Acids. — Although the
above solubility differentiation for these two classes of compounds
possesses a certain value when applied in the light of the limita-
tions, a more valuable method of differentiation is available
because of the fact that the phenol group increases enormously
the velocity of bromine substitution in the benzene ring. The
sign of reaction in carbon tetrachloride is the evolution of copious
amounts of hydrobromic acid. When the test is conducted with a
dilute aqueous solution of a phenol, the sign of reaction is the
formation of a sparingly soluble bromine substitution product.
OH
-Br+HBr
^"^ /^ Br\ 0,H OH
OH Br/Y ^™'
^
Br
COoH
/ Br Br
ecu sol'n. No reaction under experi-
+Br2 > mental conditions.
\y
CH3-(CH2)4-C02H+Br2 > No reaction under experi-
CCI4 sol'n mental conditions.
56 QUALITATIVE ORGANIC ANALYSIS
Discussion of the Reaction and of Its Limitations. — The reaction between
phenol and bromine takes place very readily at room-temperature, the
second and third atoms of bromine substituting almost as readily as does
the first to produce tribromophenol. Most substituted phenols also show
great reactivity, as is indicated below, but replacement of the H of the
phenolic — OH group by alkyl or acyl radicals decreases the reactivity.
Problem 22. — Write the reactions between bromine and (a) sahcylic acid,
(b) p-nitrophenol, and (c) fluorescein.
The phenohc structure adds to the ease of substitution into the benzene
ring, not only of bromine, but of other groups, such as chlorine, nitro, sulfonic
etc.; it also tends to the instability of the aromatic nucleus toward perman-
ganate o.xidation. In order to oxidize side-chains in the presence of the phenol
group, it is necessary to protect the latter. How? The amine group also
increases the ease of substitution in the aromatic nucleus and this fact must
be remembered in testing basic compounds. Bromine in carbon tetra-
chloride may also attack certain aldehydes, ketones and esters, both in the
aliphatic and the aromatic series. This is true especially among the types
which exist to a considerable extent in the enolic forms, since the mechanism
of substitution in such cases is no doubt first an addition of bromine to the
enoUc form, followed by the elimination of hydrobromic acid. The use of
carbon tetrachloride as a diluent possesses the advantage in that bromine is
more readily handled, it acts as a solvent for the organic compounds, hydro-
bromic acid is insoluble in this solution, and the reaction velocity is somewhat
lowered. A number of hydrocarbons which react readily with liquid bromine
react only slowly in carbon tetrachloride solution.
Phenols having para or ortho positions unoccupied couple readily with
diazonium compounds; tliis is simply another example illustrating the ease
of substitution.
The Ferric Chloride Phenol Test.^ — Many phenols give typical
blue, green, purple, or red colors when a drop of ferric chloride is
added to a dilute aqueous solution of the unknown. A number
of phenols which do not give this test readily are found to respond
when tested in alcoholic solution. Among the carboxy deriva-
tives of phenol, those having the carboxyl group ortho to the
phenolic hydroxyl, as in salicyhc acid, respond with a typical deep
purple color, but many compounds with the carboxyl group in the
meta or para position fail to respond to the test.
.CO2H /CO2H
\ /\ CI
O-Fe/ + HCl
\C1
^OH -f FcCls ^
iCf. Ann. 323, 1, 10, 20 (1902).
CLASSIFICATION REACTIONS OF ORGANIC COMPOUNDS 57
Typical enols, which, like the phenols, possess an -OH group united
to the unsaturated carbon, give deep red colorations, a fact which has been
used in connection with the investigation of tautomeric substances.
a-Hydroxy acids may produce a yellow color and some common aliphatic
acids, like acetic, give the well-known red color under suitable experimental
conditions. Example: The quaUtative test for acetic acid in inorganic
chemistry.
.Other Reactions of the Phenol Group. — The phenolic group possesses many
reactions in common with the alcohohc group; thus, acyl chlorides react
readily with most phenols to form esters. Diphenyl carbamine chloride,
/^
(C6H6)2N-C — CI, a common reagent used in preparing derivatives of the
phenols, is more reactive toward the phenolic than toward the alcoholic
group and this is true also of alkyl sulfates which react readily with the
sodium salts of phenols to produce alkyl ethers. Several of the common
phenols may be condensed with phthalic anhydride to produce phthaleins.
Reactions of the Carhoxyl Group. — Important reactions of the carboxyl
group, — C — O— H, are (a) salt formation, (6) esterification, (c) formation
of acyl halides, (d) formation of amides, and (e) loss of CO2.
Salt formation is typical of all the compounds listed in Group IV. A
partial differentiation between the various members of this group has already
been considered in connection with the differentiation of the carboxylic and
sulfonic acids from the weakly-acidic substances upon the basis of solubility
in NaHCOs solution. Acidic compounds should be titrated with standard
alkali (p. 138) and the neutral equivalents determined. The carboxyHc acids
will give practically the same neutral equivalents whether the titrations
are carried out in aqueous or alcoholic solution. Feebly acidic compounds
will show an abnormally high neutral equivalent, especially when titrated
in aqueous solution.
Important reactions, such as esterification, the formation of acyl halides
and amides, anhydride formation of certain dicarboxylic acids, and related
reactions will be illustrated in 'the section dealing with the preparation of
derivatives.
Problem 23.— Although the compound, H-0-^^^^ ^>— C— NH2, does
not contain a carboxyl group, it yields an ethjd ester when refluxed with
alcoholic HCl. By means of equations, write the reactions involved.
Volatility Constants of Aliphatic Acids. — The mono carboxylic
derivatives of the paraffin hydrocarbons up to and including those
containing six carbon atoms are readily volatile with water vapor.
These acids differ very widely in their degrees of volatility when
diluted solutions are subjected to distillation, and accordingly
Du Claux^ has based upon this fact a quantitative method for the
1 Ann. chim. phys. [5] 2, 289 (1874); Analyst 20, 193, 217 (1895); J. Am.
Chem. Soc. 39, 731, 746 (1917).
58 QUALITATIVE ORGANIC ANALYSIS
estimation of individual acids and for some of their mixtures.
Although open to certain objections from the quantitative stand-
point, the method is of considerable value in connection with
qualitative organic analysis, and is therefore presented in
Chapter IX, Exp. 16.
CHAPTER IV
CLASSIFICATION REACTIONS OF THE SIMPLE NITROGEN
AND SULFUR COMPOUNDS
BASIC NITROGEN COMPOUNDS
With a few exceptions, the basic organic compounds contain
nitrogen. When solubility tests have placed a compound in
Group III but elementary analysis has failed to prove the pres-
ence of nitrogen, it will be advisable to repeat the tests for the
elements. The most important basic nitrogen compounds are
the amines; the discussion in Chapter II has dealt with the effect
of various substituting groups upon the basicity of the amine
group and this section (pp. 19-21) should be reread in connec-
tion with the present discussion.
The first test to be apphed to basic compounds is the acylation
test: Ammonia, primary amines, and secondary amines are
readily acylated, whereas tertiary amines usually undergo no
similar reaction although in the latter case addition products with
acyl halides may be formed.^
The most important acylating agents used in the laboratory
are:
(1) Acetyl chloride and acetic anhydride,
(2) Benzoyl chloride,
(3) Benzenesulfonyl chloride,
(4) Phthalic anhydride.
As has already been pointed out in Chapter III, the acyl
halides and anhydrides react readily with the hydroxyl groups of
alcohols and phenols. This fact must be kept in mind in connec-
tion with tests for amines. Acid chlorides of low molecular
^ Dehn, J. Am. Chem. Soc. 36, 2091 (1914). At higher temperatures, an
alkyl group may be replaced by the acyl group. Ber. 19, 1947 (1886).
59
60 QUALITATIVE ORGANIC ANALYSIS
weight, particularly acetyl chloride, react readily with water.
Benzoyl chloride, benzenesulfonyl chloride, and similar deriva-
tives, however, may be safely used to test for amines in the pres-
ence of water. Why?
H
2C6H5-NH2 + CHs-C^Cl -> CeHs-N-C^CHs + CeHg-N^H
|\h
CI
o
C6H5-NH2+CH3-C-0-C-CH3 -^
CeHs-N^ C^CHa + CHsC^OH
In the above equations, it should be noted that acetyl chloride
does not convert aniline completely into the acetyl derivative
since the by-product, aniline hydrochloride, is formed and this
does not act readily with the reagent. On the other hand, with
acetic anhydride the amine is converted quantitatively into the
acyl derivative and therefore this latter reagent is of more im-
portance in connection with the preparation of derivatives. It
is also of value in quantitative estimations of the amine group, the
excess of acetic acid which remains after the reaction being deter-
mined volumetrically. Benzoyl chloride, benzenesulfonyl chlo-
ride, and other acyl halides that may be used in aqueous solution
may also convert the amine completely into an acyl derivative
for the reason that they are usually used in the presence of alkali
which will combine with the hydrochloric acid generated in the
reaction. When benzoyl chloride is used, a small amount of
benzoic acid may be formed, due to the following side-reaction:
C6H5-C^Cl+2NaOH -> CoHs-C^ONa-FNaCl+HaO
The slight excess of benzoyl chloride that is generally used in the
reaction must be destroyed completely in order to prevent it from
contaminating the derivative. The benzoic acid, however,
remains in the solution as sodium benzoate, whereas the benzoyl
derivative of the amine is insoluble in alkali unless some acidic
group like carboxyl is simultaneously present.
Problem 24. — Criticise the following laboratory test: One-half cc. of the
unknown (basic compound, b.p. 190°-195°) was treated with an equal
volume of acetyl chloride. A violent reaction took place and a solid deriva-
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 61
tive was formed. A portion of this solid was removed from the test tube
and transferred to a clay-plate in order to remove most of the adhering oil
and finally was washed by several applications of ether. The snow-white
crystals remaining failed to check in melting-point with the acetyl deriva-
tives of any amine boiling in the neighborhood of 190°-195°.
The acyl halides and anhydrides react with the amine group
more readily than with the hydroxyl group. For example, when
an amino phenol is treated in water solution with one mole of
acetic anhydride, the acetyl group will substitute the amine
hydrogen atom far more rapidly than the hydrogen of the
hydroxyl group.
/
CHs
O
/-
0
4- CHs-C^O-C-CH
^OH
•N^
-C^CHs
+ CH3-CO2H
\
OH
In ortho aminophenols, acyl groups may migrate from the
oxygen to the nitrogen atom.
.OH
/
\
I^N^C^CHs
NH2
This is simply an illustration of the reaction of an ester with an
amine to form an amide, except that in the above case the ester
and the amine groups are located in the same molecule.
Differentiation between the Various Classes of Amines. —
A. Primary, secondary, and tertiary amines may be differentiated
by a combination of the acetyl chloride and the isonitrile tests.
R— NH, 4-
Cl
CI
3K0H
>■
R— K=^C+3 KCH-3 HoO
62
QUALITATIVE ORGANIC ANALYSIS
TABLE XVIII
Unknown + Acetyl Chloride
Positive reaction.
I or II amine
Heat original amine with CHCI3 and alcoholic potash
Positive reaction.
I amine
No reaction.
II amine
No reaction.
Ill amine
In this test, the formation of an isonitrile is detected by the
extremely disagreeable odor that is typical of this class of com-
pounds. The test is not very satisfactory because it is too delicate
and consequently most secondary amines, which usually contain
traces of primary amines, will respond to the test. Exceptions
are also found, especially among the amines of high molecular
weight.
B. Benzenesulfonyl chloride (and other aryl sulfonyl chlo-
rides) possess an advantage over the usual acyl chlorides of the
acetyl or benzoyl type in that the sulfonyl derivatives of primary
amines may be differentiated from the corresponding derivatives
of secondary amines due to the solubility of the former in alkali.
This reaction will be discussed further in Chapter XII in connec-
tion with its apphcation to mixtures.
Problem 25. — Write the structural formulas for sulfonyl derivatives of
I and II amines and explain why these derivatives behave differently in
their reactions with dilute aqueous NaOH solution.
C. Phthalic Anhydride reacts with many I and II amines very
readily, even without heating; III amines show no reaction.
C^
R-NH2+
o
o
c
./
o
H
I
-N-R
C^OH
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 63
>NH +
R/
o
>0
c^
''^
\R
C— OH
The derivative of the I amine may be differentiated readily
from the other. When heated sHghtly above its melting-point
a dehydration reaction occurs with the formation of a product
no longer soluble in alkali.
C^^^N-R
-C^OH
heat
/
O
>N-R + H2O
The reactions of the amines discussed above, with the excep-
tion of the isonitrile test, are of importance not merely for the
classification of compounds but also for the preparation of solid
derivatives and in some instances for the examination of mix-
tures. Such reactions, which serve simultaneously as classifica-
tion and as identification reactions, are ideal for the purposes of
organic analysis.
The Behavior of Amines Towards Nitrous Acid is also occa-
sionally of value to differentiate between the three classes of
amines. In these reactions, primary amines behave somewhat
differently from the secondary amines. Ammonia also reacts,
and, indeed, we have here simply an example of the method of
preparing nitrogen which was studied in inorganic chemistry.
NH3 + HNO2
H/H
HN^O-N=0
H
N2 + 2H2O
Primary aliphatic amines also form nitrites which decompose
in a manner analogous with the decomposition of ammonium
nitrite except- that in this instance nitrogen gas and an alcohol
are formed. This decomposition is not as rapid, however, as one
64 QUALITATIVE ORGANIC ANALYSIS
might wish for qualitative tests. When the primary amine group
is in the alpha position in respect to a carboxyl group, as in many
of the common amino acids, a very rapid reaction with nitrous
acid takes place with a practically quantitative evolution of nitro-
gen gas. The Van Slyke method for the quantitative determina-
tion of the alpha-amino acids is based upon this reaction. The
-NH2 group of amides will also react with the formation of an
acid and nitrogen gas. This reaction is also less rapid than is the
reaction with the alpha-amino acids.
Secondary aliphatic amines react with nitrous acid to give
nitroso derivatives which are practically neutral substances and
insoluble in water unless the amine is of very low molecular weight.
Tertiary aliphatic amines do not react with nitrous acid under the
usual conditions except to the extent of salt formation.
H
I /H
R-NH2 + H-0-N=0 ^ R-N^H -^ N2 + R-OH + H2O
\0-N=0
"R T? TT R
^NH-HH-0-N=0 ;:± ^N^H -> \n-N=0-KH20
R/ R/ \0-N==0 R/
R\ R\ /H
R^N+H-0-N=0 ;^ R^N<
R/ R/ \0-N=0
In the aromatic series, we find that primary amines react
extremely readily in the cold to form intermediate water-soluble
products known as diazonium compounds. When the diazonium
solution is warmed, decomposition takes place with the forma-
tion of nitrogen gas and a phenol.
-N< HCl
\H + HO-N=0 >
V
-N2CI heat
H2O
)H
+ N2 + HCl
These diazonium compounds are extremely valuable in synthetical
work, since the diazonium group may be replaced with a large
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 65
variety of other groups, such as CI, Br, I, CN, H, OC2H5, NO2,
SO2H, etc. These special appHcations of the diazonium com-
pounds are seldom used in qualitative work since the simpler
reactions are usually sufficient.
In addition to replacement reactions, the diazonium com-
pounds readily undergo coupling reactions with many phenols
and amines. These reactions, which are of great technical impor-
tance, are also of value in both qualitative arid quantitative
organic work.
Problem 26. — What reagents and conditions are used to replace the
diazonium group with (a) chlorine, (b) — C=N, and (c) hydrogen? How
may a diazonium compound be converted into a hydrazine?
Problem 27. — Write the equations to illustrate the coupling reactions
of diazonium compounds with phenols and with tertiary aromatic amines.
Secondary aromatic amines behave as do the corresponding
amines in the aliphatic series; they form nitroso compounds
which are neutral substances and only sparingly soluble in water.
They separate from solution when the amine hydrochloride is
treated with sodium nitrite solution. Occasionally, when these
nitroso compounds are solids, they may be used for derivatives.
The Tertiary Amines. — This class of amines differs from
ammonia and the primary and secondary amines in its non-
activity with acyl halides and anhydrides.
Many amines, including the tertiary type, form double salts
with such reagents as chloro-platinic acid, picric acid, etc. These
derivatives are of importance in analytical work in connection
with identification tests. The formation of picrates, however,
is not peculiar to the amines; in fact, such derivatives may be
prepared even from the hydrocarbons of the naphthalene and
anthracene series.
Tertiary amines may add alkyl halides and form quaternary
ammonium compounds which are often solids with definite melt-
ing-points. The alkyl iodides are usually applied for this purpose.
R
R I R'
R-n/ + R'X -^ R— N<f
\R I \X
R
An important reaction of aromatic tertiary amines consists in
the formation of nitroso derivatives when the amine salt in acid
66 QUALITATIVE ORGANIC ANALYSIS
solution is treated with sodium nitrite. This reaction is typical
mainly when the para position to the amine group is unoccupied.
/CH3
/N< -HCl
/CH3 X CH3
-N< HCl (\
^CHs + H-0-N=0 > + H2O
k.
N=0
Since in the above reaction-product the nitroso group is on carbon
and not on nitrogen, we obtain a compound which is still basic
and thus differs from the nitroso derivatives of aromatic secondary
amines. The introduction of the nitroso group leads to instability
of the molecule towards alkah.
yCHs heat
CgHs-N^ + NaOH solution > no reaction
^CHs
yONa
/CH3 /\
.N< (1) heat f ^ /CH3
C6H4< ^CHs + NaOH > + H-N
^N=0(4) solution l^ / ^CHa
^N=0
An important class of tertiary amines is represented by com-
pounds of the pyridine and quinoline types. Although these
classes are considered as aromatic in character, the basic N
atom does not add to the ease of substitution into the nucleus.
These cyclic amines behave more Hke the tertiary aliphatic
amines since they do not form nitroso derivatives, and they do
not couple with the diazonium compounds. Addition products
with the alkyl halides are formed very readily.
Other Basic Nitrogen Compounds. — The hydrazines, unless
negatively substituted on the nitrogen, are typical organic bases.
Phenylhydrazine (CGH5-NH-NH2) is only sparingly soluble
in water but dissolves readily in dilute HCl. When a second
aryl group is introduced,
H H
<^_i.i_^^^
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 67
we obtain a hyclrazo compound which is practically neutral. Hydra-
H H
I ^0 1
zines possessing the structures R-N-NH2 and R-C N-NH2,
are detected by using benzaldehyde or some other convenient
carbonyl compound as a reagent.
Problem 28. — Write the equation for the reaction between (a) vanillin,
and NHo— NHo, (6) hydrazobenzene and aqueous HCl.
The diazonium hydroxides are fairly strong bases. These compounds
and their salts have been discussed in connection with the reactions of
primary aromatic amines. Although very important in organic work, the
diazonium compounds are rarely found among the compounds requiring
identification. This is easily understood when we recall that most of them
are stable in solution only at comparativeh^ low temperatures. In the
form of dry solids, most of the salts are highly explosive.
/^
-N=N
\/ OH \/
-N=N-OH
Benzene diazonium hydroxide
Quaternary ammonium hydroxides, (R)4:X— OH, are very strong bases
like the highly ionized inorganic hydroxides. They are seldom met, and
then usually as chlorides or sulfates. They are manipulated best in the
form of platinic chlorides.
Carbamide (urea) forms salts with one mole of acid (NH2 • CO • NH2 • HNO3),
but in water solution they are mostly hydrolyzed and the acid may be
titrated, even with phenolphthalein as an indicator. The enzjTne prepara-
tion "urease" is convenient for the identification and estimation of urea.
Amidines, some guanidine derivatives, imino-ethers, etc., are not suffi-
ciently common to require individual attention here. Oximes, when water-
insoluble, occasionally give evidence of basic properties by increased solu-
bility in dilute HCl.
Problem 29. — Write the equation for the action of sodium hypobromite
in alkaline solution upon (a) benzamide, and (&) urea.
Acidic Nitrogen Groups. — When a hydrogen of ammonia is
replaced by an acyl group of a strong acid (sulfonic acid), an
acidic amide is formed. A similar result is obtained by intro-
ducing two acyl groups derived from carboxylic acids, thus
resulting in the formation of an imide (page 20). An examina-
tion of the tautomeric (lactam and lactim) formulas for these
compounds suggests an analogy with the structure of the car-
68 QUALITATIVE ORGANIC ANALYSIS
boxyl groups, since here also an -OH group is linked to a carbon
N-
which is unsaturated; viz.: -C-OH in place of -C— OH.
Similarly, there are nitrogen groups which may be considered
as related to the carboxyl group but which possess the nitrogen
(tri- or pentavalent) replacing the carbon of the carboxyl; e.g.,
O O
II and II in place of ||
N-OH =N-OH -C-OH
Compounds containing these groups are acidic, although in the
case of oximes, very feebly acidic. They are often met in a dif-
ferent guise, the above formulas representing simply the " aci "
form of primary and secondary nitroso and nitro compounds.
See page 22 and Problem 4.
Tertiary nitroso and nitro compounds do not exhibit this type
of isomerism except in special instances in the aromatic series
when, due to the presence of certain other groups, the derivative
may exist in the form of a quinone-like compound.
OH 0
N-OH
The acidic nitrogen groups may be subjected to the same class
reactions which are used for the neutral nitrogen groups and a
separate discussion will therefore be unnecessary.
Neutral or Indifferent Nitrogen Groups. — The four most com-
mon indifferent nitrogen groups are the nitro, azo, nitrile, and
amide. The following discussion will deal also with a number of
other analogous groups that are met only occasionally in ele-
mentary analytical work. These classes of compounds may be
arranged conveniently into two sub-groups:
(a) Easily reducible type,
(6) Easily hydrolyzable type.
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 69
The nitro and azo compounds are readily reduced by acid
reducing agents to yield primary amines.
R-NC + 6H -> R-N< + 2H.0
R-N=N-R'+4H -> R-NH2 + R'-NH2
In the above reductions, the amines are present in the form of
salts of the inorganic acid used. In the iron reduction method,
however, where only a very small amount of acid is used as a
catalyzer, the amines are present mostly as free amines, and for
this reason in the reduction of fairly volatile substances pro-
vision must be made to prevent loss either of amine or of the initial
material.
The reducing reagents which are commonly used in the labora-
tory are :
(a) Tin and aqueous HCl,
(6) Iron powder and 5 per cent iron chloride and water,
(c) Zinc and neutral salt solutions,
(d) Sodium amalgam,
(e) Stannous chloride in HCl solution,
(/) Zinc and acid.
(g) Zinc and alkah.
As will be seen from the subsequent discussion (see also Problem
35), the reaction of the medium exerts a great effect upon the
particular reduction products to be formed.
Problem 30. — The reducing agents above are given in the order of
importance for laboratory work in qualitative anal.ysis. Explain how and
why this order differs in technical manufacturing work.
Amides and nitriles may be readily hydrolyzed to produce the
corresponding acids together with ammonia or, in the case of
certain amides, substituted ammonia. To be sure, the amides
and nitriles may also be reduced to amines, especially with sodium
in alcoholic solution; with acidic reagents the hydrolytic reaction
is, however, the prominent one and the one adaptable for ana-
lytical purposes.
^0 acid /^O
R-C^NH2 + H2O > R-C^0H+NH4X
acid ^O acid ^O
R-C=N + H20 > R-C^NH2 — > R-C^OH + NH4X
70 QUALITATIVE ORGANIC ANALYSIS
The hydrolysis of amides and nitriles may be conducted not
only in acid solution but also in the presence of alkali. When
dealing with substances soluble in water only with difficulty, it is
customary to use alcohol as a solvent. In the latter instance, in
connection with acid hydrolysis, the organic acid formed in the
reaction is partially converted into an ester, whereas ammonia,
or a substituted ammonia, will be present in the form of a salt
with the inorganic acid used. When the hydrolysis is conducted
in the presence of alkali, the organic acid is present as the sodium
or potassium salt, whereas the amine is liberated and, if volatile,
may be lost when the reaction mixture is refluxed. Type experi-
ments are illustrated in connection with the laboratory work,
page 146.
Problem 31. — Write the equations for the acid hydrolysis of
(a) CeHs-NCHa-COCHa,
/CO— NH.
(6) CH,<' \C0,
^CO— NH^
(c) CcHs-CO-NH-CH.CO-NH-CeHfi.
In which reaction is a gas evolved?
Problem 32. — Write the equations and state the experimental conditions
for
(a) the conversion of an amide into a nitrile,
(h^i the formation of an amide from an ester.
Problem 33. — Write type formulas for compounds belonging to each
class listed in Table XIX under Groups A, B, and C.
Analytical Attack of Indifferent Nitrogen Compounds
Many of the types in Subgroup A represent colored compounds
and the few individual members which are not colored when pure
are often contaminated with colored impurities. The simple
nitro and azoxy compounds are usually light yellow or cream
colored, whereas the azo compounds are more highly colored.
Additional substituents, for example, amine groups, will deepen
the color of nitro compounds. Many simple nitroso compounds
are green.
-
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 71
TABLE XIX
Sub-group
A.
Sul>group B.
Sub-group C.
Easily reduced
Easily hydrolyzed
Resistant to reduction and
hydrolysis
Nitro
Amides
Some negatively substi-
tuted amines
Azo
Nitriles
Certain imides
Nitroso
Imides
Many sulfonamides
Azoxy
Derivatives of aldehydes
Certain heterocyclic types
Hydrazo
and ketones:
(a) Hydrazones
(b) Oximes
(c) Semicarbazones
(d) Osazones
(e) Aldehyde amine de-
rivatives
(/) Cyanohydrins
Isocyanates
If a given unknown containing indifferent nitrogen is a color-
less compound, it is advisable to apply first the hydrolysis test
for Subgroup B. On the other hand, colored compounds should
be subjected to reduction tests before resorting to those involving
hydrolysis. Often a combination of the two tests is advisable,
alkaline hydrolysis being resorted to when no definite results are
obtained by acid hydrolysis.
With the exception of the nitro and hydrazine compounds,
practically all of these compounds may be quantitatively analyzed
for nitrogen by the Kjeldahl method. The nitro compounds
may, of course, be utilized also in such an analysis following
slight modifications from the usual method of analysis.
Discussion of Subgroup A. — The nitrogen compounds in this
class may all be reduced to amines by means of acid reduction
methods, but they differ considerably in ease of reduction. Fur-
ther differentiation within the subgroup may often be made by
the choice of modified methods of reduction. In many instances
the order of reduction is as follows: Nitroso, azoxy, nitro, and
azo, the first being reduced most readily. This order differs,
however, in regard to the character of the reducing reagent and
is modified greatly by the solubility of the compound. In order
V
72
QUALITATIVE ORGANIC ANALYSIS
to hasten the reduction of sparingly soluble compounds, alcohol
is often added.
The inter-relation between these compounds is shown in the
following diagram:
R-N-0
2H
^R-N-O-H
R-N
^
0/2H
\
O
2r-n:
/
O
\
b\6H
r-n-^pr^r-n-^n-r^^r-n-n-r
0
H H
The nitro, azo, nitroso, and azoxy compounds may all be
reduced to the hydrazo stage by means of zinc dust and alkali in
the presence of alcohol. In this reaction, however, the azoxy
compounds may often be differentiated from the azo, due to the
fact that the former are reduced more readily and upon reduction
go through the deeply-colored azo stage.
Many nitroso and nitro groups can be reduced by zinc and
water in the presence of a small amount of a salt like ammonium
chloride as a catalyzer to form hydroxylamine derivatives which
readily reduce ammoniacal silver nitrate.^ The nitroso group
may be differentiated by oxidation (HNO3) to the nitro stage.
Problem 31. — What is Liebermann's Nitroso Reaction?
(191G).
(Mulliken II, 30
Hydrazo compounds may be oxidized back to the azo stage
by passing air into the solution of the compound in alcoholic
alkali solution. In glacial acetic acid, 30 per cent hydrogen per-
oxide gradually oxidizes both hydrazo and azo compounds to the
azoxy compounds.
Cf. Mulliken II, 32 (1916).
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 73
Several of the types mentioned in the above table are easily
affected by treatment with strong acids. This is especially true of
the hydroxylamine, nitroso, and hydrazo compounds.
CH3 CH3
^ H H 9 V + dil. HCl
<3-N-N-<;
y
Hydrazoanisole
CH3 CH3
o o
HCl • H2N-<^ /~\~ /-NHs-HCI
Dianisidine HCl (pp'-di-amino-
mm'-di methoxy-dip henyl)
Problem 35. — What products are formed when aryl nitro compounds are
reduced with zinc in
(a) neutral solution,
(6) alkaline solution,
(c) acid solution?
How may a similar variety of products be prepared by electrolytic reduc-
tion?
Problem 36. — What is formed when sodium methylate acts as a reducing
agent on nitrobenzene? Will reduction take place when hydrogen gas from
a Kipp generator is passed into boiling nitrobenzene?
In this series of indifferent nitrogen compounds, it is not
essential, however, that an unknown be limited to one individual
class before proceeding with the work; the identification of the
products obtained by reduction or hydrolysis together with the
physical constants and other properties of the original unknowil,
will serve to simplify the procedure greatly.
Problem 37.— In a manner analogous with the explanation of the benzidine
rearrangement, explain the formation of p-aminophenol from phenyl hydroxyl-
amine and sulfuric acid. What is the semidine rearrangement?
Problem 38. — Hydrazo compounds are colorless. Why do the samples
met with usually possess a yellow color. How can we explain that nitroso-
benzene is green only when in the liquid or vapor phase? What suggestion
can be given for the deepening of color when the nitrophenols are converted
into their salts?
Discussion of Subgroup B. — With the exception of formamide,
the common amides are solids with fairly high melting-points and
usually limited solubility in ether and benzene. The nitriles of the
74 QUALITATIVE ORGANIC ANALYSIS
corresponding acids are generally liquids or low-melting solids
unless several -C^N groups are present. The fact that the
nitriles may yield amides as intermediate products in their hydrol-
ysis to acids can serve as a method of differentiation. The
nitriles will yield ammonia upon complete hydrolysis, whereas
amides may be derived from primary and secondary amines as
well as from ammonia.
The various nitrogenous derivatives of aldehydes and ketones
are usually detected by the products formed by acid hydrolysis.
The corresponding carbonyl compounds may be isolated often,
and sometimes the nitrogenous products as well. By sodium
reduction many of these compounds yield amines, but this re-
action is of minor analytical importance.
Problem 39. — Given the phenylhydrazone of methyl ethyl ketone,
recover the ketone as such and the phenylhydrazine in the form of its benzal-
dehyde derivative.
Problem 40. — Two oximes of benzaldehyde are known. Explain this
case of isomerism. Do both oximes yield nitriles with acetic anhydride?
What is the Beckmann Rearrangement of ketoximes?
Discussion of Subgroup C. — The di- and tri- aryl amines
(negatively substituted amines) are practically neutral substances,
and naturally are not affected by the usual hydrolytic treatment.
Aromatic amines with ortho nitro groups are very feebly basic;
when heated with alkali, ammonia is gradually liberated. (Cf.
equations, page 66.)
The imides are often met among the acidic substances, but
when the hydrogen of the > NH group is replaced with a radical
they become neutral. Such compounds, particularly when
derived from cyclic structures of the phthalimide and saccharine
types, are hydrolyzed only with difficulty under the conditions of
the usual experiment. They are placed, therefore, in Subgroup
C. Their hydrolysis is usually carried out by heating with HCl
to a temperature of approximately 200° in a sealed tube. The
sulfonamides, also, are resistant to hydrolysis, and most of them
may be placed in Subgroup C. They are acidic substances unless
both the hydrogens of the -NH2 group have been replaced by
radicals. Certain heterocyclic types, for example, the purine
derivatives, although possessing the amide structure, are less
susceptible to hydrolysis because of the greater stability given
by the ring structure.
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 75
The Sulfur Compounds
The main classes of sulfm* compounds to be considered are:
Thiols (mercaptans and thiophenols),
Sulfides, including cyclic sulfides,
Disulfides,
Sulfoxides,
Sulfones,
Sulfinic Acids,
Sulfonic Acids and derivatives,
Esters of sulfuric acid,
Sulfates of organic bases, and
Sulfite addition-products of carbonyl compounds.
A glance at the formulas for the above types will emphasize
the close relationship between oxygen and sulfur; thus the thiols,
sulfides, and disulfides are analogous with the oxygen compounds,
alcohols, ethers, and peroxides, respectively. Alcohol-like and
phenolic types, are found among the thiols just as with the cor-
responding oxygen compounds. The analogy may be carried to
additional examples. For instance, carbon oxysulfide and car-
bon disulfide are related to carbon dioxide: C^=0, C=S, C^^S.
Related to the carboxylic acids are found compounds in which
one or both of the oxygens of the carboxylic group are replaced
by sulfur:
^O X.S x-O X.S
R-C^OH, R-C^OH, R-C^SH, R-C^-S-H
In general, these sulfur compounds possess the reactions of the
corresponding oxygen compounds plus the reactions conveyed
by the ability of sulfur to assume valences of four or six.
In a second type of sulfur compounds, sulfur is found usurping
the place of carbon ; for example, related in structure to the ketones
are the sulfoxides and sulfones, and related in structure to the
carboxyl group are the sulfinic acids. Since sulfur may possess
a variable valence, it may give rise also to sulfonic acids which
bear the same relation to the sulfinic acids that sulfuric does to
76 QUALITATIVE ORGANIC ANALYSIS
sulfurous. These relationships are indicated in the following
formulas :
^O /yO ^O
R-C^OH, R-S^OH, R-Sf OH
^O
Carboxylic acid Sulfinic acid Sulfonic acid
With the exception of the sulfonic acids and the sulfates, the
above sulfur compounds are of importance only in a few special
cases, and a detailed discussion of individual classes is therefore
inadvisable in an elementary course. The derivatives of sulfonic
acids, such as the sulfonyl chlorides, amides, and imides are of
considerable importance in qualitative work.
Carbon Disulfide possesses the ability to form addition
products: thus
S
//$> alcohol II
C^S + NaOR y R-0-C-S-Na
solution
,_N=C=S
The former reaction is of technical importance in the manufacture
of viscose and the latter is valuable both in the laboratory and
in the industries. A corresponding reaction with phenylhydrazine
is of value in preparing a derivative of carbon disulfide.
The Thiols and Sulfides are chiefly liquids with penetrating,
disagreeable odors. With salts of heavy metals, such as mercuric
chloride, the former yield salts and the latter double salts.
R-SH + HgCl2 -> (R-S)2Hg
R-S-R + HgCl2 -^ R-S-R-HgCl2
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 77
Those thiols (mercaptans) related to the alcohols are scarcely
acidic enough to yield stable salts with dilute aqueous alkali,
while those possessing phenolic properties (thiophenols) dissolve
in dilute alkali. Certain thiophenols are alkali-insoluble for the
same reason that certain high-molecular-weight phenols are alkali-
insoluble.
The most important reactions for compounds which may be
considered as derivatives of hydrogen sulfide are the oxidation
reactions. The usual reagent is either nitric acid or perman-
ganate. For the oxidation of the sulfides to sulfoxides and sul-
fones, 30 per cent H2O2 in acetic acid as a solvent is a convenient
and rapidly acting reagent. The thiols may be oxidized readily
to the disulfides by any one of several reagents, such as NaOI,
H2O2, and occasionally by the oxygen of the air.
R-S-H
30
R Sf OH
^0
2R-SH
10
>
R-S-S-R + H2O
R-S-S-R
50
2R-S|- OH
^0
R-S-R
10
>
0
II
R-S-R
0
II
R-S-R
10
^0
R— S^— R
^0
0
II
R-S-R
II
— — >
fairly stable to oxi(
II
0
Problem 40a. — Write the structural formula for the compound known in
chemical warfare as " mustard gas." Knowing that the corresponding
sulfoxide is practically non-toxic, how would you attempt to prevent mustard
78 QUALITATIVE ORGANIC ANALYSIS
gas burns in recently exposed tissues? J. Am. Chem. Soc. 42, 1208, 1230,
(1920).
The low molecular weight sulfoxides and sulfones like
O O
II II
C2H5-S-C2H5 and C2H0— S— C2H5
II
O
are, as might be expected from their structure, slightly soluble
in water. The members possessing higher molecular weights,
however, are only sparingly soluble. The greater solubility of
the sulfoxides is due probably to a reaction with water and their
presence in solution as R-S^ — R .
\0H
The isothiocyanates are of some importance since a few mem-
bers are found in natural products. They are broken down by
acid hydrolysis, as was noted also among the oxygen analogues,
the isocyanates, to produce primary amines.
acid hydrolysis
2CH2=CH-CH2-N=C=S + 2H2O >
(Allyl isothiocyanate from mustard) rl2oW4
(CH2=CH-CH2-NH2)2H2S04 + 2C0S
The most common sulfur compounds met in organic analysis
are the sulfonic acids. The aromatic members are the most
important since they are easily prepared and possess important
technical uses.
In contrast to the sulfinic and carboxylic acids, the sulfonic
acids are very highly ionized. As might be expected from their
structure, they are fairly soluble in water and the lower members
are therefore isolated usually in the form of salts. Many sulfonic
acids may be hydrolyzed by heating with 25 per cent to 50 per
cent sulfuric acid to yield the corresponding hydrocarbons or
derivatives. The ease of hydrolysis differs with different mem-
bers, and it appears that those compounds which are sulfonated
most readily yield sulfonic acids which hydrolyze the most easily.
Benzene sulfonic acid does not yield benzene except under special
THE SIMPLE NITROGEN AND SULFUR COMPOUNDS 79
conditions of hydrolysis. Toluene sulfonic acids hydrolyze with
less difficulty, and the o- and m-xylene sulfonic acids, faii'ly readily.
SO3H
/^/^ HOH + H2SO4
+ H2SO4
+ heat
'CHa
CH3
HOH + H2SO4
>
+ heat
— CH3
+H2SO4
SO3H
The sulfonic acid group in phenols and amines may often be
displaced by halogen in connection with the usual bromine-
water test.
Another important technical reaction of the sulfonic acids is
hydrolysis by fusion with caustic alkaUs. In quahtative work,
this is of minor importance.
Probelm 41. — Write the equations for the following reactions:
(a) Fusion of sodium benzene sulfonate with caustic alkali,
(6) Distillation of sodium benzoate with soda Hme,
(c)- Heating of anthraquinone-/3-sulfonic acid with ammonia under
pressure,
{d) Fusion of saccharin with caustic alkali.
As was the case with the carboxylic acids, the sulfonic acids,
also, may be converted into acyl chlorides and identified as such
or in the form of the amides. Since sulfonic acids and their salts
usually crystallize with water of crystaUization, it is important
that they be dried for some time at 100° before subjecting them
to the treatment with phosphorus pentachloride. The presence
of other groups (such as OH, NH2, etc.), which also react with
PCI5, will be expected to interfere with the preparation of the
acyl chlorides.
80 QUALITATIVE ORGANIC ANALYSIS
Compounds Containing Special Elements. — Many metals are
met in organic analysis in connection with the examination of
salts. This part of the subject will require no special treatment,
however, since the general method of attack consists in identifying
the organic compound after it has been liberated from its salt.
The organic basic compounds are often met, of course, in the
form of their salts with inorganic as well as with organic acids.
Occasionally an organic compound is found combined with inor-
ganic material as a double salt. Among the organo-metallic
compounds, derivatives of magnesium, zinc, mercury, etc., are
valuable laboratory reagents, although they are infrequently
met in connection with organic analysis.
In the pharmaceutical field, organic arsenic, mercury, anti-
mony, and phosphorus compounds are receiving increased atten-
tion, and similar examples might be given from other specialized
lines of applied organic chemistry. An attempt to treat such
specialized lines is inadvisable here.
CHAPTER V
COMPOUNDS WITH UNLIKE SUBSTITUENTS
The majority of the derivatives of the hydrocarbons (saturated
and unsaturated) contain more than one substituent, and among
these poly-substituted derivatives a considerable number contain
unlike substituents. Among the commoner organic compounds
this distribution is more equable, however; thus in the Tables
in Part C, we find listed the constants for about two thousand
fairly common organic compounds. This number is divided
approximately as follows:
I. One substituent, 30 per cent,
11. Two or more like substituents, 10 per cent,
III. Two or more unlike substituents, 60 per cent.
Important classes of compounds which fall in the third sub-
division are:
(a) Carbohydrates and their derivatives,
(6) Amino acids and their derivatives,
(c) Ureides, and
(d) Dyes.
In addition to these specialized types, each solubility group
will contain other classes of compounds with unlike substituents
and a part of the present chapter will deal with the possible effect
of such compounds upon the simplified classification and method
of analysis outlined in Chapter I. No pretense is made to treat
the above specialized types except in a general elementary man-
ner; more advanced texts are already available, dealing with
analytical work in these respective fields.
A systematic procedure of analysis might be expected to lead
to narrowness on the part of the student ; this is too often the case
in inorganic " ion " analysis. Fortunately, organic analysis can-
not be narrowed down to an analytical procedure which is inde-
81
82
QUALITATIVE ORGANIC ANALYSIS
pendent of a thorough knowledge of organic chemistry and of the
abiUty to use that knowledge; the mixed classes of compounds,
particularly, will prevent such an occurrence. The present chap-
ter gives only a glimpse into the field; a region in which each or-
ganic chemist must develop by practical experience in the special-
ized line in which he is working.
CARBOHYDRATES
The carbohydrates are compounds containing carbon, hydro-
gen, and oxygen, usually of the composition Cre(H20)„or«-i, w-hich
contain the sugar or " ose " group either free or in combination.
H /O ...
The " ose " group is represented as -C-C — or a structure m equi-
I
OH
librium with this form.
Formula I represents an aldohexose with the free sugar group;
Formula II represents a disaccharose of the sucrose type with the
sugar groups in combination.
CH2OH
CHOH
CH
CH2OH
CHOH
CH
CHOH
CHOH O
H— C-OH
CHOH
CHOH O
CH2OH
CHOH
CH
HO-CH
CHOH
CHOH
H-C
i
CHoOH
I
CHOH
CHOH
I
CH
I
,c-
o
CrnOH
-0
CHoOH
I
CHOH
I
CHOH
I
CHOH
I
CHOH
I
H— C-OH
\h
I
II
COMPOUNDS WITH UNLIKE CONSTITUENTS 83
The structures in (I) represent what is commonly known as
the lactone formulas for a sugar ; thus, c?-glucose is known in two
forms, alpha and beta d-glucose. Either isomer in solution is
gradually converted into an equihbrium mixture which is repre-
sented by (I). This rearrangement, known as a muta-rotation,
is hastened by the addition of a trace of alkali, a fact which is of
importance in connection with the determination of the specific
rotation of any sugar possessing the free " ose " group. The
individual shown in II does not muta-rotate. The aldo sugars,
although possessing a potential aldehyde group do not give the
fuchsin-aldehyde test. An exception is noted also in the case of
chloral hydrate, which compound possesses its aldehyde group
H ,0H
in combination with water to produce the structure, -C^
The presence or absence of the free sugar group enables a classi-
fication of compounds into (a) reducing sugars, and (6) non-
reducing sugars.
The reducing sugars react readily upon heating with Fehling's
Solution to give a precipitate of cuprous oxide; the second class
gives no reaction with this reagent. The non-reducing sugars,
however, may be hydrolyzed with varying degrees of ease to
mono-saccharoses which react in the normal manner with the
Fehling reagent.
Problem 42. — Explain why a disaccharose, like maltose or lactose,
Ci2H220n, will react with Fehling's Solution.
Problem 43. — The formula CeHiaOe represents (o) how many aldohexoses,
(6) how many ketohexoses?
Fehhng's Solution may be represented as equivalent to a
solution of cupric oxide and the reaction may be written
as follows:
CH2OH CH2OH
I I
(CH0H)4 + 2CuO -> (CH0H)4 + CuaO i
C=0 C=0
84 QUALITATIVE ORGANIC ANALYSIS
The reaction is actually somewhat more complex, not only in
respect to the reagent ^ but also in respect to the products formed
from the sugars, since the secondary alcohol groups in the sugar
acid represented above are also susceptible to oxidation. Never-
theless, the method is available even for quantitative estimation
provided that the procedure is carried out in a specified empirical
manner.
A more nearly typical reaction of the sugar group is that with
phenylhydrazine, resulting in the formation of an osazone. The
first step is exactly analogous with the usual aldehyde and ketone
reactions. Upon continued heating with phenylhydrazine solu-
tion, the alpha -CHOH group is oxidized by a molecule of
phenylhydrazine to produce a carbonyl group, which then reacts
again with phenylhydrazine to form a double hydrazone, known
as an osazone.
CH2OH
(CH0H)4 C6H5NHNH2
1
C=N-N-C6H5
\h H
CH2-0H
CH2OH
(CH0H)3 C6H5NH-NH2
1 >
(CH0H)3
1 _.._., y
c=o
1
C=N-NH-C6H5
(b=N-NHC6H5
C=N-N-C6H5
\h 1
H
* The copper in Fehling's Solution is held in combination by the tartaric
acid in a form which prevents the precipitation of cupric hydroxide. Upon
electrolysis of such a solution, the copper travels with the negative ion to
the cathode. This complex ion is often represented as,
/O-CH-COaG
Cu< i
\O-CH-CO20
Reaction with Fehling's Solution is not typical of the sugar group; many
other substances, both organic and inorganic, may reduce Fehling's Solu-
tion.
COMPOUNDS WITH UNLIKE SUBSTITUENTS 85
The various sugars differ in ease of reaction with phenylhy-
drazine, and consequently the " time test of osazone formation "
(page 144), is of value in giving information concerning a given
unknown in this group. The crystalline structure and to a minor
extent the melting-points of the osazones are also of aid in identi-
fication work. Easily hydrolyzable non-reducing sugars, like
sucrose, may yield osazones because of the fact that hydrolj^sis
gradually takes place under the conditions chosen for the experi-
ment. Such sugars naturally require a greater time for osazone
formation.
Problem 44. — Explain why glucose, mannose, fructose, and sucrose give
identical products in the osazone reaction.
The specific rotation is a particularly valuable constant for
sugars as well as for many of their derivatives. This is of special
importance for the reason that the usual melting-point test applied
to poly-hydroxy compounds is somewhat dependent upon the rate
of heating, and additional physical constants are therefore
desirable.
In a few instances, sugars may be isolated in the form of the
simple hydrazones, but in general these derivatives are too soluble
in water. By choosing hj^drazines of higher molecular weight,
benzyl phenylhydrazine, /3-naphthylhydrazine, etc., hydrazones
may be more readily isolated. Aldoses may be differentiated from
CH3
ketoses by the use of asymmetrical hydrazines like C6H5-N-NH2.
Ketoses yield the typical osazones, whereas aldo-sugars form
only the colorless hydrazones.^
Problem 45. — According to the solubility rules in Chapter 11, would you
expect a hexose hydrazone to be more soluble than the corresponding osazone?
Would you expect lactosazone to be more or less soluble than glucosazone?
In addition to the reactions already discussed, the sugars
possess other typical reactions of the carbonyl, hydroxyl, and
ether (acetal) linkages, together with a number of more specific
reactions. Only a few of these will be mentioned for the reason
that many of them are of synthetical rather than of analytical
value.
1 Weyl, Part I, pp. 471-2 (1911).
86 QUALITATIVE ORGANIC ANALYSIS
In connection with other aldehydes, the aldo-sugars may form
acetal-hke compounds when heated with anhydrous alcohol in
the presence of a trace of HCl.
HCl CH2OH
C6H12O6+CH3OH
CHOH
I
CH
(CH0H)2
I
HC-OCH3
O
Methyl hexoside
This acetal linkage is present in the poly-saccharoses and con-
sequently these compounds may readily be hydrolyzed to yield
mixtures of mono-saccharoses. When sucrose is thus hydrolyzed,
the process is called inversion. Why?
dil. HCl
Sucrose + H2O > Glucose + Fructose
The hydroxyl groups of carbohydrates may be acetylated by
heating with acetic anhydride in the presence of dehydrating
agents such as fused sodium acetate or zinc chloride. Aldo- and
keto-hexoses form penta-acetyl derivatives, whereas disaccharoses
like sucrose, maltose, and lactose form octa-acetyl derivatives.
Pentoses, pentosides, as well as polyoses which yield pentoses upon hydrol-
ysis, readily form furfural,
CH— CH
II II /H
CH C-C=0
\o/
when distilled with dilute mineral acids. This heterocyclic aldehyde may be
identified as the phenylhydrazone; it may be detected qualitatively due to
the formation of an intensely colored red dye with aniline acetate solution. In
quantitative work, pentoses are determined by converting them into furfural
and estimating the latter either with phloroglucinol ^ or with thiobarbituric
acid.i
The pentoses are not fermented by yeast enzymes, whereas most hexoses
are readily attacked. Alcoholic fermentation has been observed among
trioses, hexoses, and nonoses, which is in agreement with the equation :
enzyme
(CR^O-dx > XC2H5OH + 2CO2.
» J. Am. Chem. Soc. 38, 2156 (1916).
COMPOUNDS WITH UNLIKE SUBSTITUENTS 87
The formula (CeHioOs)! represents the complex carbohydrates
such as dextrins, starches, and cellulose. A general test for these
classes as well as the simple carbohydrates already discussed is the
Molisch color test, which is based upon the colors produced when
a trace of carbohydrate material is treated with sulfuric acid in the
presence of a-naphthol.^
Starch occurs in the form of granules which differ considerably
in appearance according to the plant from which it is obtained.
Microscopic examination is therefore of considerable aid in learning
the source (potato, rice, corn, rye, etc.). In cold water, the gran-
ules are insoluble but they swell and burst upon heating and yield
colloidal starch solutions. Starches give a typical blue color even
with traces of iodine, but are readily hydrolyzed by diastase to
dextrins, which no longer respond to this typical test, and finally
to reducing sugars. Dextrins, as well as starches and cellulose,
may be hydrolyzed by means of mineral acids to yield reducing
sugars.
AMINO ACIDS
The most common aliphatic amino acids possess the formula
H
R-C-CO2H.- They are derived not only from mono, but also
I
NH2
from dicarboxylic acids, and among the members from natural
products a few are known to possess an amino group on a carbon
atom other than the a-carbon. Lysine, a, e-diaminocaproic
H
acid, NH2-CH2-CH2-CH2-CH2-C-CO2H, is probably the best
I
NH2
known example of the latter type.
1 MuUiken, Vol. I, p. 26.
2 The radical R- may be H as in glycocoU; alkyl as in a-alanine, leucine, etc.;
-CH2OH as in serine;
— C-CH2- /^\
11 ■ . . ^ CH C— CH2- . , . ,. ,. .
I as in tryptophane, 1 11 as in nistidine,
^^^N-CH N CH
H H
HO—/ y" — CH2- as in tyrosine;
-CH2-S-S-CH2- as in cystine, etc.
88 QUALITATIVE ORGANIC ANALYSIS
Amino acids give deep red colorations with ferric chloride and,
as would be expected from their relation to ammonia, give a deep
blue color with solutions of cupric salts. The simple a-amino
acids are practically neutral in reaction; they may be considered
as inner salts.
H H H
R-C-C^O-H ^ R-C-C-^ or R-C-C^O-N^H
•I I I Hx I |\h
NH2 H-N-0 h4N-0— C-C-H
A h/ II I
HH OR
As might be expected from these structures, the lower members,
like glycocoU and alanine, are very soluble in water but insoluble
in ether. (Solubility Group II.) Members of higher molecular
weight fall in Groups III and IV. In general, they do not possess
definite melting-points.
With nitrous acid, the a-amino acids react very readily to yield
nitrogen gas and a-hydroxy acids which usually cannot be isolated
with ease. An excellent volumetric method for the estimation
of amino acids is based upon this reaction. ^
In the presence of an excess of concentrated hydrochloric acid
and the calculated amount of NaN02, the chloro derivatives of the
aliphatic acids are obtained, often in good yield.- The most
valuable reaction of amino acids for use in the qualitative labora-
tory is the preparation of acyl derivatives. Valuable reagents^
for this purpose are benzoyl chloride, benzene sulfonyl chloride,
/3-naphthalene sulfonyl chloride, and jS-anthraquinone sulfonyl
chloride, all of which may be used with aqueous solutions of amino
acids, since these acyl chlorides are only slowly decomposed by
water. When benzoyl chloride is used, the product obtained
may be contaminated with a small amount of benzoic acid, which
may usually be removed because of its greater solubility in ether.
The benzoyl derivatives of the amino acids are often rather
sparingly soluble in ether as is true of many amides.
The acyl chlorides derived from sulfonic acids possess the
advantage that the organic acid formed as a by-product is usually
1 Van Slyke, J. Biol. Chem. 12, 275 (1912); 16, 121-125 (1913).
2 Z. Physiol. Chem. 31, 119 (1900).
3 Ber. 35, 3779 (1902); Ber. 33, 3526 (1900).
COMPOUNDS WITH UNLIKE SUBSTITUENTS
89
soluble in water. Benzene sulfonyl chloride is the most common
reagent of this type used in qualitative work. When the cor-
responding sulfonyl derivatives are too soluble in water, a high
molecular weight acyl halide, anthraquinone sulfonyl chloride,
may be used.
O
II
^\^ ^,^^— SO2CI N-C-CO2H
+ H I
/
R
' Hi
/\
0
H H
— S02-N-C-C02H
1
R
II
0
+ HCl
Peptides
The polypeptides are compounds in which the carboxyl group
of one amino acid has reacted with the amino group of a second
amino acid to produce an amide structure.
./
O
H
./
O
NH2-CH2-C^-OH + CHs-C-C^OH
I
NH2
H
H
>N-CH2-C^-— N-C-CO2H + H2O
H/ I
CH3
Glycyl alanine, the compound formed in the hypothetical reac-
tion above, is called a dipeptide. Continued amide formation with
additional amino acids would lead to the formation of tri- and
tetra-peptides, etc. These polypeptides possess in addition to
the reaction of the amino acids the hydrolytic reactions due to
90 QUALITATIVE ORGANIC ANALYSIS
the presence of the amide structure. They are products which
have not only been prepared synthetically but which have also
been isolated as intermediate products in the hydrolysis of
proteins.
Since the sulfone amides are hydrolyzed less readily than the
amides of carboxylic acids, we have in benzene sulfonyl chloride
a reagent not only for the isolation and identification of some of
these substances but also a means for determining the structure
of a given product.^ For example, glycocoU and alanine may be
combined to yield two different products. After reaction with
benzene sulfonyl chloride and hydrolysis of the resultant products,
we shall obtain in one instance a glycocoll residue united to the
sulfonyl radical, whereas in the second instance alanine is obtained
in the form of its sulfonyl derivative.
Proteins
The proteins form the bulk of the nitrogenous contents of
plant and animal cells. They contain chiefly carbon, hydrogen,
oxygen, and nitrogen, the percentage of the latter varying between
narrow limits (15 to 17.5 per cent). Small amounts of sulphur
are often present, and occasionally also phosphorus. These
compounds are of very high molecular weight, usually non-
crystallizable, and in solution are present in the colloidal state.
They may be hydrolyzed to yield amino acids and other products
whereas some individuals among the conjugated proteins yield
also purines and pyrimidine bases, phosphoric acid, and car-
bohydrates.
Soluble proteins may usually be precipitated by a variety of
reagents, and many of them may be coagulated by heating.
Some of the common salts, like ammonium sulfate, sodium sulfate,
sodium chloride, etc., serve for " salting out " of many of these
members in the unaltered condition, while certain acids (picric,
tannic, phosphotungstic, phosphomolybdic, etc.) serve for their
removal as insoluble salts.
In addition to the precipitation reagents, a large variety of
color-tests is in use for the detection of proteins. (A) In Millon's
Reaction, the material is treated with nitric acid, in which a small
1 Ber. 40, 3548 (1907).
COMPOUNDS WITH UNLIKE SUBSTITUENTS 91
amount of mercury has been dissolved. Upon heating, the pro-
tein assumes a red color. (B) Under the formidable name of
Xanthoproteic Reaction, so-called because of the production of a
yellow color, we meet a common test for the phenolic group. When
a drop of nitric acid is placed upon the skin, a yellow stain develops
which, when washed and treated with alkali, turns to a deep orange.
(C) The Bu'uet Test is based upon the colors produced (pink to
bluish) when the protein, in strongly alkaline solution, is treated
with a very dilute copper sulfate solution. When present in
urine, albumin may be detected by the nitric acid ring test either
by the formation of a white zone of precipitated albumin or by
the heat coagulation test followed by the addition of a drop of
acetic acid.
The proteins are usually classified into three groups:
I. The Simple Proteins yield only alpha-amino acids or their
derivatives upon hydrolysis: this group comprises albumins,
globulins, glutelins, prolamines, albuminoids, histones, and
protamines.
II. Conjugated Proteins contain the protein molecule united
with some other molecule in some manner other than as a salt,
Nucleoproteins, glycoproteins, phosphoproteins, hemoglobins,
etc., are typical members.
III. Derived Proteins are formed from the first two groups,
due to hydrolytic changes. The group comprises proteans,
metaproteins, coagulated proteins, proteoses, peptones, and
peptides.
Further classification of the simple proteins is of interest to
the student of organic analysis because of the appHcation of sol-
ubility behavior for the classification of this group of complex
natural products, viz.:
Simple Proteins:
1. Albumins. Soluble in water but coagulated by heat.
2. Globulins. Insoluble in water but soluble in neutral
salt solution.
3. Glutelins. Insoluble in neutral solvents but soluble in
dilute acids and alkali.
4. Prolamines. Insoluble in water but soluble in 70 per
cent alcohol.
5. Albuminoids. Insoluble in all neutral solvents.
92 QUALITATIVE ORGANIC ANALYSIS
6. Histones. Soluble in water but precipitated by am-
monia.
7. Protamines. Soluble in water but not coagulated by
heat.
For analytical work m tnis special field, the advanced texts
referred to at the end of the chapter should be consulted.
AROMATIC AMINO ACIDS
Many amino acids derived from aromatic acids differ appre-i
ciably from the aliphatic type because of the feeble basicity of
the amine group. In general, these compounds possess definite
melting-points and appreciable solubility in ether. Since the
amino group is very feebly basic (page 20), these acids may
usually be titrated in the presence of phenolphthalein and a
fairly accurate neutral equivalent obtained. A specific example
will be treated below in the general discussion of compounds
containing several reactive groups.
In addition to derivatives of aromatic carboxylic acids, a large
number of amino derivatives of aromatic sulfonic acids is known.
Many of these compounds are of importance as dye intermediates.
Due to the presence of the sulfonic acid group, they are no longer
ether-soluble. Many of the members are of fairly high molecular
weight and hence of limited solubility in water. Acids of this
type, together with phenolic sulfonic acids and compounds,
which possess both the phenolic and the amino groups, are met in
commerce under names such as the following: H acid, F acid,
Gamma acid, G salt, R salt, Broenner's acid, Cleves' acid,
Neville and Winther's acid, etc.
A few of the commoner members are known by names which
are more suggestive of their structure, such as sulfanilic acid,
metanilic acid, naphthionic acid, etc.
THE UREIDES
O
Urea, NH2-C-NH2, is the amide of carbonic acid. It may be
condensed with various acids to produce substituted amides which
are known as ureides. In addition to these simple compounds,
COMPOUNDS WITH UNLIKE SUBSTITUENTS 93
several groups of cyclic ureides are of importance, particularly
the purines, pyrimidines, and hydantoins.
Ni=6CH N=CH HN— CH2
I 1 H II I
H-C2 5c— N\ HC CH 0=C
II II >C-H8 II II I
N3— 4C— N9^ N— CH HN— C=0
Purine Pyrimidine Hydantoin
Although the mother substances, purine and pyrimidine, are not
themselves important, many of their derivatives occur in natural
products. Only a few can be mentioned here.
2, 6-Dihydroxy purine Xanthine
2, 6, 8-Trihydroxy purine Uric Acid
2, 6-Dihydroxy-3, 7-dimethyl purine Theobromine
2, 6-Dihydroxy-l, 3-dimethyl purine Theophylline
2, 6-Dihydroxy-l, 3, 7-trimethyl purine Caffeine
6-Hydroxy-2-amino purine Guanine
These compounds exhibit typical reactions which may be pre-
dicted according to their structures; some of them, however,
possess unusual stability towards hydrolysis when compared with
the simple urea derivatives. Such variations in stability are no
doubt associated with the stabilities of the heterocyclic structures.
Thus, the purines or pyrimidines may be considered as possessing
/^\
C C
a nucleus, || | , which in some respects is comparable with
N C
the benzene nucleus. Hydantoin, on the other hand, when heated
with dilute alkali, readily hydrolyzes to hydantoic acid and then
into ammonia, carbon dioxide, and glycocoll. It is feebly acidic,
as might be expected from the imide structure, and appreciably
soluble in water, as might also be predicted from its structure, and
the melting-point of 216°.
Uric acid is a fairly strong acid; it dissolves readily in dilute
alkali, and is precipitated from alkaline solution in the form of a
sparingly soluble acid-salt by means of carbon dioxide. It is
fairly resistant towards hydrolysis. Caffeine, on the other hand,
94 QUALITATIVE ORGANIC ANALYSIS
possesses no acidic hydrogen but is feebly basic, as might be ex-
pected from its structure. Heating with alkali results in hydro-
lytic action.
Problem 46. — Predict the products formed when creatinin
H-N— C=0
I
HN=C
I
CHs-N— CH2
is subjected to hydrolysis by boiling in alkaline solution.
An important test often applied to the purine derivatives in
order to differentiate them from other amides is the murexide
reaction. A small quantity of the compound (1/100 g.) is
moistened with a few drops of 1/1 HCl. A minute crystal of
KCIO3 is added and the mixture evaporated on a crucible cover
upon the steam-bath. A pinkish or yellowish color is usually
apparent at this stage, and this color deepens upon gentle warm-
ing of the residue over a free flame. After cooling, the reaction
product is moistened with a drop of ammonia water, which
results in the production of a purplish color. ^
Nitrogen determinations by the Kjeldahl method are impor-
tant in connection with the identification of compounds of this
type.
ALKALOIDS
The alkaloids are basic compounds possessing at least one
heterocyclic nitrogen atom. These compounds, many of which
exhibit powerful physiological action, occur generally in certain
plants. The term alkaloid is often applied, however, in a broader
sense so as to include compounds of the purine and pyrimidine
types which occur in the animal body as well as in plants. Many
members of the latter type are not basic but, like uric acid, are
really acidic compounds. A still broader classification might
include many other nitrogenous compounds, natural as well as
synthetic (adrenalin, novocaine, etc.), which do not contain
heterocyclic nitrogen atoms but which exhibit physiological
behavior suggestive of the vegetable alkaloids.
In general, the alkaloids possess a variety of unlike substitu-
ents although certain members are relatively simple and may be
1 Ber. 30, 2236 (Suppl.); Mulliken, 2, 31.
COMPOUNDS WITH UNLIKE SUBSTITUENTS 95
considered as substituted hydrocarbons possessing only one or
two reactive groups. For example, coniine behaves exactly Hke
other secondary amines, nicotine is relatively more complex,
whereas in atropine we have an example of the presence of a
variety of unlike groups in the same molecule.
/CH2\ CH2 — CH2
II
CHo CH2 //\ Att /.tt
I I r^\ 9^'
CH2 CH-CH2CH2CH3 I \N/
\ / ^N^ I
\^/ CH3
JT Nicotine
Coniine
CH2 — CH CH2
I I
N-CH3 CH-O-CO-CH-CeHs
I I I
CH2— CH CH2 CH2OH
Atropine
Problem 47. — Point out the asymmetric carbon atoms in the formulas
for coniine, nicotine, and atropine. Are the natural products optically
active?
What is formed when coniine is subjected to exhaustive methylation?
(Ref. Stewart, Recent Advances in Organic Chemistry, 1918, pp. 125-6.)
Such compounds, even when a considerable number of unlike
substituents is present, will occasion no special difficulty. The
well-known members, including a few the structures of which are
not known with certainty, are included in the tables for common
organic compounds given in Part C.
The reason for a specialized treatment of alkaloids in most
schemes of analysis is not due to any unusual variation from the
reactions predicted for the substituents present but because of the
powerful physiological action of many individual members. Be-
cause of the latter reason, the compounds are often met in
extremely minute quantities, as for instance, in connection with
the toxicological examination of animal tissues. In such instances,
the methods of microanalysis are frequently of value.
Since alkaloids often occur in minute quantities, classification
based upon color reactions with various alkaloidal reagents is
generally used. The individual members may sometimes be
detected by means of their typical physiological behaviors.
9t) QUALITATIVE ORGANIC ANALYSIS
For work in this field, the larger texts must be consulted, par-
ticularly the special treatises upon the subject. References are
given at the end of this chapter.
ORGANIC DYES
The common classes of organic dyes are the following:
f Monoazo,
(1) AzoDyes: \ Di-azo,
I Tri-azo, etc.
Malachite green series,
(2) Triphenylmethane
Dyes:
Rosaniline series,
Auramines or Rosolic acid series,
Phthaleins, Rhodamines, and Eosines,
f Pyronines,
(3) Diphenylmethane , . ...
^ ' _ < Acridmes,
I Auramines,
I Anthraquinone type (Indanthrenes),
(5) Anthracene dyes of the alizarin type,
(6) Nitro and Nitroso dyes,
(7) Sulfur dyes (Sulfide colors, Thiazines, etc.),
Indamine,
Indophenols,
(8) Diphenylamine Dyes: i Thiazine,
Oxazine,
. Safranines.
Problem 48. — As an exercise, the student should write the formulas for
various dyes found in the above classes. He may limit himself to the specific
classes which are studied in his general course in organic chemistry.
Problem 49. — Give a list of (a) the common chromophore groups, (6)
the common auxochrome groups.
The examination of organic dyes, particularly because of the
large number of individual compounds and mixtures ordinarily
met in technical products, is work for the specialist. Attempts
have been made toward the systematic grouping of dyes based
upon chemical reactions. Thus the scheme of Rota^ is based
iChem.Zeit. 1898,437.
COMPOUNDS WITH UNLIKE SUBSTITUENTS
97
upon the behavior of dyes towards various reducing and oxidizing
agents. Rota has suggested the following classification:
TABLE XX
Unknown in 1 : 10,000 Solution (Water or Alcohol)
Treat with dilute HCl and SnClo
Reduction to colorless solution.
Neutralize and add FeCls.
No reduction by SnCl2.
To original solution add 20 7o KOH
and warm
Color not restored
Class I
Color restored
Class II
Decolorization or
precipitate
Class III
No precipitation
and color deep-
ens
Class IV
Further discussion of this scheme of classification and the
methods used for subdivision of the four main classes is not justi-
fiable in the space available here.
Effective work in connection with the identification of dyes
usually requires also actual dyeing experiments. A particularly
valuable physical property which is utilized in connection with the
identification of dyes is the absorption spectrum of dye-solutions.
A more recent and far more extensive treatment for the identi-
fication of dyes has been developed by Mulliken. Identification
of Pure Organic Compounds, Vol. III. About fifteen hundred
dyes are classified in this extended treatise. The method of
attack is as follows:
(1) Homogeneity test (a) water, (6) sul-
furic acid, (c) fractional dyeing,
(d) capillary absorption, (e) spec-
troscopy,
(2) General appearance and color,
(3) Solubilities in water, alcohol, sul-
furic acid,
(4) Tests for sulfur dyes,
(5) Direct dyeing of wool and cotton,
(6) Dyeing with hydrosulfite vat,
(7) Dyeing with sodium sulfide vat.
Preliminary Tests:
98
QUALITATIVE ORGANIC ANALYSIS
Generic or Divisional
Tests:
Coordination Tests:
(8) Discharge of direct wool dyeings by-
sodium formaldehyde sulfoxylate,
(9) Restoration of color by air,
' (10) Restoration of color by potassium
persulfate,
(11) Color discharges and returns on vat-
dyed cotton.
f Action of H2SO4 on textile dyeings,
Action of NaOH on textile dyeings.
Action of nitrous acid on wool dyeings.
Special Tests:
Precipitation tests — H2SO4, NaOH, sulfates of
Ca, Cr, Cu, and tannin,
Dyeing on mordanted wool,
Diazotization and -development with /3-naphthol,
Reduction products of azo dyes.
Absorption spectra.
Verification test and use of color standard.
The scheme proposed by Mulliken naturally finds more or less
criticism from the specialists in the dye industry. No doubt much
valuable information has been developed in the research labora-
tories of the dye works but only a limited amount of such data
becomes public property. The technical worker who is most
prolific in his criticism is usually the one who is most secretive
with his own results.
The particular dyes which are permitted by the U. S, Govern-
ment in foods and beverages have been limited to ten.^ These
have been selected because they are relatively harmless; they
may be readily manufactured in the pure condition; and they
may be readily identified. ^ These colors, which are also met in
the form of mixtures, may be classified as follows:
Red shades
107. Amaranth,
56. Ponceau 3R,
517. Erythrosine.
1 U. S. Dept. of Agriculture, Decisions Governing Colors in Food.
2 Leach, Food Inspection and Analysis.
COMPOUNDS WITH UNLIKE SUBSTITUENTS 99
Orange shade
85. Orange I.
Yellow shades
4. Naphthol yellow S,
94. Tartrazine,
Yellow A.B. (Benzenazo-/3-naphthylamine) m. 103°,
Yellow O.B. (Ortho-toluenazo-/3-naphthylamine) m.
126°.
Green shade
435. Light green S.F. yellowish.
Blue shade
692. Indigo disulfoacid.
The numbers preceding the names refer to the numbers of the colors as
hsted in A. G. Green's edition of the Schultz-JuHus Systematic Survey of
the Organic Coloring Matters, published in 1904.
An important reaction of the azo dyes consists in their reduc-
tion to the corresponding amino compounds. An important
reagent for this purpose is stannous chloride in hydrochloric acid
solution. In this reduction, compounds are broken between the
two nitrogens of the azo group and from the resultant simpler
compounds, the structure of the original dye may often be deduced.
Problem 50. — An azo dye upon reduction yielded benzidine, p-amino-
dimethylaniline and l-amino-2-hydroxynaphthalene on reduction. What is
the structure of the dye and what products serve as intermediates for its
manufacture?
Problem 51. — What are the indanthrene dyes? (Ref. Stewart, Recent
Advances of Organic Chemistry, 1918, p. 6.)
EFFECT OF POLY-SUBSTITUTION
In the discussion of chemical reactions, we have for the most
part considered simple type compounds. Several examples have
been met which demonstrate that the simultaneous presence of
several substituents may lead to a modification of the usual
reactions. The present section will summarize some of the
examples already discussed and will offer additional illustrations
from the standpoint of possible effect upon the proposed scheme
of analysis.
In Chapter II, we noted the fact that the -NH2 group in an
organic molecule may be basic, neutral, or even acidic ; the par-
ticular behavior towards ionization depends upon the group joined
100 QUALITATIVE ORGANIC ANALYSIS
to the amine nitrogen. Groups which when substituted into the
molecule lower the basicity of a base or increase the acidity of an
acid are often spoken of as negative groups. It is not essential
that the negative group be directly joined to the amine group.
Aniline is a weak base but substitution by the nitro group decreases
the basicity still farther. Meta and p-nitraniline are only feebly
basic but there is no doubt but that they fall in solubility Group III.
A nitro group in the ortho position, however, exerts a still greater
effect and we find o-nitraniline and 2, 4-dinitraniline to be almost
insoluble in dilute acids. Halogens exert an effect similar to, but
less powerful than, the nitro group. The substitution of three
halogen atoms into aniline jaelds a compound that is only feebly
basic.
The union between carbon and nitrogen is fairly stable towards
hydrolysis; negative substitution, however, leads to instabihty.
R— NH2 > heat
I + alkali > No reaction.
Ar-NH2 J
/NHsO) heat /OH(i)
CeHK + alkali > CeH^ +NH3
^N02(2 or 4) \N02(2 or 4)
Nitro groups exert a similar effect upon the labilization of
halogen, the effect being greatest in the ortho position.
/CI
ale. sol'n No reaction unless at
+ alkali + heat > very high temperature
under pressure.
CI /ONa
— NO2
+ NaCl + HoO
NO2
+ 2NaOH 4- heat
The union between carbon and carbon is generally very stable
and is ruptured only by high-temperature reactions. We have
already observed, page 43, however, that in the structure
O O
II II
-C-CH2-C-
COMPOUNDS WITH UNLIKE SUBSTITUENTS 101
we can readily disrupt the union between carbon and carbon.
This is true also when a carbon atom adjacent to the carbonyl
is heavily substituted by halogen.
CAC-C^H + aq. NaOH -> CHCI3 + H-C^ONa
CK
Ac-C^CHs + aq. NaOH -* CHI3 + CH3C02Na
\/
Carboxylic acids do not readily lose carbon dioxide except at
high temperatures or when fused with caustic. When two car-
boxyl groups are joined to the same carbon atom, one molecule of
carbon dioxide is readily lost:
R\ /CO2H heat to
>C< > R-CH2CO2H + CO2
W \CO2H about 150°
Dicarboxylic acids with the two carboxyl groups in the a, /3 or
a, 7 positions readily undergo anhydride formation when heated
either alone but preferably with dehydrating agents. Such reac-
tions are expected when the substituent groups are in positions
favoring formations of 5- or 6-atom cyclic structures.
Problem 62. — Illustrate the formation of succinic, maleic, and phthalic
anhydrides. What is produced when calcium glutarate is subjected to a
high temperature? /
A reaction analogous with that of cyclic-anhydride-formation is
the formation of lactones from 7-hydroxy acids and from 7-halo-
gen acids. (Cf. page 39.) A related reaction is the dehydration
of acids possessing a carbonyl group in the gamma position.
P OH . ^
CH3C-CH2CH2CO2H- CH'3C=CH-CH-2C02H^^^ CH3C=CH-CH2C=0 +H2O
Levulinic acid \h^c;CH2CH2C02H^^CHiC-CH^CH2CO+H,0
i 0 — '
Problem 53. — According to the theory of geometrical isomerism, one of
the above lactones may exist in two forms. Explain this case.
102
QUALITATIVE ORGANIC ANALYSIS
a-Hydroxy acids and a-amino acids may also form anhydrides
but in such instances two molecules of the substituted acid (or
derivative) are concerned.
H
O
2CH3-CHOH-CO2H
2NH2-CH2-C^OR
CH3— C— C^O
O— C— C-CH3 + 2 H2O
II I
O H
CH2-C^^jj
\C CH2
II
o
+ 2R0H
a-Hydroxy acids are readily decomposed when heated with
sulfuric acid, to yield carbon-monoxide and a carbonyl derivative.
The formation of an unstable a-lactone structure, by dehydration
reaction, is probably responsible for this behavior. By analogous
reaction, oxalic acid is expected to furnish equal volumes of carbon
monoxide and carbon dioxide.
R OH
\ /
/-
//
0
OH
^x A'/
C-;c
R
R
-> C=0-l-CO
R
Problem 54. — /3-Lactones are usually utistable and break down to yield
carbon dioxide and an ethylene derivative. Write the equation for such a
reaction.
The hydrolysis reaction of 1, 3 diketones have already been
considered. The 1, 2 diketones in the aromatic series when heated
in alkaline solution show an interesting reaction — the rearrange-
ment to hydroxy acids.
C<^ /OH
C^COaNa
NaOH
\y
COMPOUNDS WITH UNLIKE SUBSTITUENTS 103
Problem 56. — Write the equation for the reaction of 1, 2 diphenyl-ethane-
dione-1,2 with concentrated alkaU. What is the name for this rearrange-
ment?
Problem 56. — What is the pinacone-pinacolin rearrangement?
Although this treatment of the behavior of poly-substituted
compounds is necessarily limited, sufficient material has been pre-
sented to show that these so-called complications are not such in
reality, but instead are of considerable aid in analytical work;
even the present superficial treatment of the subject may have
served to suggest that these apparent exceptions are fairly general
among themselves and therefore may be utilized for further sys-
tematization of the work.
BEHAVIOR OF POLY-SUBSTITUTED COMPOUNDS IN CONNEC-
TION WITH IDENTIFICATION WORK
The question concerning possible complications introduced in
the scheme of analysis by the occurrence of compounds possessing
two, three, or four substituents will be treated with a few examples,
presenting, however, only a part of the usual laboratory data.
(a) The formula, CeHs^-O — C— R, represents an ether, an
\CO2H
ester, and a carboxylic acid. The preliminary tests will probably
detect only the acidic group and this will place the compound in
Group IV, but until we have proof to the contrary we shall consider
the possibility of the simultaneous presence of any number of indif-
ferent groups. The relatively high neutral equivalent (above 200)
suggests the possibility that indififerent groups are present. We
may therefore test for the presence of such groups, remembering,
however, that the acidic group known to be present may compli-
cate our tests slightly. In applying a phenylhydrazine test, for
example, we shall consider the possibility of precipitation of a
hydrazine salt. The most common tests to which we shall sub-
ject such unknowns, in addition to tests with Br2 water, FeCla,
etc., are attempts at hydrolysis with alkali or acid. Since the
unknown is soluble in dilute alkali, the alkaline solution is refluxed
for a short time. Acidification precipitates an acid but melting-
point and neutral equivalent show that the original substance has
104 QUALITATIVE ORGANIC ANALYSIS
undergone hydrolysis, and the change in neutral equivalent tells
us the molecular weight of the group that has been eliminated.
Moreover, the recovered acid in contrast to the original unknown
now shows phenolic characteristics.
With these facts, together with the physical constants, v/e are
now prepared to turn to the classified tables of Group IV (or to
the larger reference books if necessary) and plan additional work
for the conclusive proof of identity.
/CO2H
/ gy
(6) The compound, C6H2 q_qtt > is insoluble in water but
soluble both in dilute alkali and dilute acid; we shall laler look for
the compound in both Solubility Groups III and IV. Other indif-
ferent groups may also be present. Since nitrogen is present, the
acidic group might prove to be acidic nitrogen, but since the
compound yields a reasonable value for neutral equivalent (and
a sharp end-point in titration) we provisionally assume the pres-
ence of a fairly strong acidic group like carboxjd.
Bromine is present as shown by analysis, and boiling the solu-
tion of the unknown in dilute alkali fails to remove halogen.
Because of its basic nature the compound is tested with acetic
anhydride. Since the reaction product is insoluble in dilute acid,
we conclude that the unknown is either a I or II amine, but the
sulfonyl chloride test in this case will not differentiate between
these two classes. Why not? Attempted hydrolysis b}^ boiling
in both acid and alkaline solution (why may aqueous instead of
alcoholic solutions be used?) indicates the presence of a substance
stable towards hydrolysis.
With this information at hand, we may now consult the tables
listing compounds in Groups III and IV, and plan subsequent
specific tests. A direct proof of the presence of -OCH3 will
probably be unnecessary. Kjeldahl analysis for nitrogen might
have aided in the earlier stages of analysis as well as in presenta-
tion of final evidence,
COMPOUNDS WITH UNLIKE SUBSTITUENTS 105
REFERENCES
Carbohydrates
J. B. Cohen: Organic Chemistry for Advanced Students,
E. F. Armstrong: The Simple Carbohydrates and Glucosides.
Abderhalden: Handbuch der Biochemischen Arbeitsmethoden.
Allen: Commercial Analysis, Vol. I.
C. S. Hudson: Publications in J. Am. Chem. Soc.
Amino Acids and Derivatives
R. H. Plimmer: The Chemical Constitution of the Proteins.
P. B. Hawk: Practical Physiological Chemistry.
Hammarsten-Mandel : Physiological Chemistry.
E. Fischer: Untersuchungen liber Aminosauren, Polypeptide, und
Proteine.
T. B. Osborne: The Vegetable Proteins.
Abderhalden: Biochemisches Handlexicon.
Lehrbuch der Physiologische Chemie.
Ureides, Alkaloids, etc.
A. Pictet-Biddle: The Vegetable Alkaloids.
T. A. Henry: The Plant Alkaloids.
A. W. Stewart: Recent Advances in Organic Chemistry.
E. Fischer: Untersuchungen in der Puringruppe.
S- Frankel: Arzneimittel Synthese.
P. May: Chemistry of Synthetic Drugs.
Allen: Commercial Analysis, Vols. V and VH.
N. V. Sidgwick: Organic Chemistry of Nitrogen.
Dyes
Cain and Thorpe: The Synthetic Dyestuffs and Intermediate
Products.
G. Schulz: FarbstofTtabellen.
O. Lange: Die Schwefel Farbstoffe.
H. Bucherer: Lehrbuch der Farbenchemie.
S. P. Mulliken, Vol. HI. Identification of Organic Compounds.
E. R. Watson: Colour in Relation to Chemical Constitution.
106 QUALITATIVE ORGANIC ANALYSIS
A. G. Perkin: The Natural Organic Colouring Matters.
U. S. Gov't Bulletin: Census of Dyes and Coal Tar Chemicals for
1920.
General
H. Sherman: Organic Analysis.
A. E. Leach: Food Inspection and Analysis.
G. Lunge: Chemisch-technische Untersuchungsmethoden.
J. Lewkowitsch: Chemical Technology and Analysis of Oil, Fats,
and Waxes.
PART B
LABORATORY DIRECTIONS
CHAPTER VI
PROCEDURE FOR THE ANALYSIS OF AN INDIVIDUAL
COMPOUND
Solubility reactions are made the basis for dividing organic
compounds into a definite number of groups. In the case of an
unknown substance, the elementary analysis, as well as the
physical properties of the compound, will still further narrow
down the number of possibilities. In order to decide definitely
to which homologous series a certain compound belongs, it is
necessary next to apply class reactions, i.e., homologous tests.
The unknown should be subjected to those homologous tests, and
only those, which are justified on the basis of the solubility reac-
tions and the elementary analysis; it is only in this manner that
qualitative organic analysis can receive a logical treatment.
Finally, when the homologous series to which the unknown belongs
has been located, the physical properties of the compound will
locate the individual within this series. It is desirable, however,
to follow the above procedure by a confirmatory test which con-
sists in the preparation of one or more simple derivatives and a
determination of the physical constants of the latter.
Chapter I should be re-read before proceeding with the
identification work.
107
108 QUALITATIVE ORGANIC ANALYSIS
OUTLINED METHOD OF ATTACK
The suggested steps in a systematic procedure for the identi-
fication of an individual organic compound are:
1. Physical examination,
2. Determination of constants,
3. Elementary analysis,
4. Solubility tests,
5. Homologous tests,
6. Consultation of literature,
7. Preparation of derivatives.
1. Physical Examination. — Examine the unknown for homo-
geneity, color, odor,^ crystalline structure, etc., after a careful
purification, if the compound is not pure when obtained. Observe
the behavior of the substance in the ignition test. (Exp. 1, page
122.) If the substance burns readily or leaves a carbonaceous
residue, it may be considered as organic. A few common organic
compounds rich in oxygen or nitrogen (urea, formic acid, etc.), do
not burn readily. Test any residue after ignition for alkalinity
and if appreciable in amount, thus indicating more than a trace of
impurity, examine it by the usual qualitative inorganic method.
Carefully record these observations but do not be misled or
prejudiced in your subsequent work by preliminary observations.
The color of the unknown may be due to the presence of traces of
impurities, particularly of oxidation products; an apparently
typical odor may prove to be due to a mere trace of an odoriferous
impurity.
2. Determination of Constants. — Determine first the melting-
points of solids and the boiling-points of liquids. In many instances,
both constants may be determined and, if so, this is highly desir-
able. From the behavior of solids in the ignition test, determine
whether a melting-point determination is advisable. Usually,
with salts it is necessary to determine the constants of the free
organic compound after liberation from the salt. Certain organic
hquids decompose upon distillation, and for this reason any vis-
' The taste of certain organic compounds is occasionally of value to the
analyst but because of the obvious danger involved this test should never be
applied at this stage of the analysis when the nature of the compound is
entirely unknown.
THE ANALYSIS OF AN INDIVIDUAL COMPOUND 109
cous-appearing liquid should be tested (how?) before attempting
to distil the sample.
A specific gravity determination is especially valuable for
liquid unknowns (page 118). The weighed sample should be
reserved for use in a later test where a weighed amount of material
may be required.
Other physical constants, such as refractive index, optical
rotation, semi-quantitative solubility determinations in solvents
of different types, etc., are reserved until later in the course
of analysis, since their application may possibly prove unnec-
essary.
3. Elementary Analysis. — Analyze the unknown for carbon,
nitrogen, halogens, sulfur, and metallic residue left upon ignition.
(See Chapter VII for details.) A test for hydrogen is unnecessary.
Tests for special elements — phosphorus, arsenic, lead, mercury,
etc., are not applied as a routine procedure in this course but when
such tests are necessary they will be suggested in connection with
Steps 4 and 5. In applied work, the source of the material or the
usual information concerning the use for the substance under
examination is usually of value in suggesting the advisability of
testing for special elements.
Quantitative analj^ses for any characteristic element is occa-
sionally applied in connection with the final identification in Step 7.
(See Chapter XI.) As a general rule, it is advisable to titrate
any alkaline residue left upon ignition in order to differentiate
between traces and appreciable amounts of alkalinity.
4. Solubility Tests. — Determine the solubility of the unknown
in water, dilute alkali, dilute acid, ether, and cold concentrated
H2SO4. For details and discussion see Chapters II and VIII.
Finally consult the Solubility Table at the end of this text.
5. Homologous Tests. — Prepare a list of homologous series
to which the compound might belong, drawing your conclusions
from the solubility reactions, the elementary analysis, and the
physical properties of the compound. Allow for the presence of
indifferent groups (including unsaturation) not specifically detected
in the solubility tests.
Apply homologous tests for those types (and only those)
which are included in your list of possibilities. Suggestions for
this work are obtained not only from the experimental work in
Chapter IX, but also from Chapters III, IV, and V.
110 QUALITATIVE ORGANIC ANALYSIS
6. Consultation of Literature. — After the application of class
reactions, the compound may be limited to a very small numbei
of homologous series and often to one homologous series. At this
stage, but not before, should the table of physical constants be
consulted. If the unknown is not found in these tables listing
several thousand of the simpler substances liable to be encoun-
tered then the larger reference books, such as Mulliken and Rosen-
thaler, must be consulted.
7. Preparation of Derivatives. — Apply confirmatory tests by
preparing one or more characteristic derivatives (Chapter X)
and determine the physical constants of these derivatives. A color
reaction, although of value as an indication, cannot be accepted
as a confirmatory test. Neutral equivalents, saponification
equivalents, volatility constants of certain aliphatic acids, and
quantitative estimation of groups, are occasionally equivalent
to a derivative. Usually one typical derivative is sufficient but
the amount of confirmatory work will depend upon the require-
ments for the differentiation between the individual compounds
that are accepted as possibilities after completion of the work in
the preceding six sections.
LABORATORY NOTES
Record all observations directly into your laboratory note-
book and do this in the order in which tests are made as directed
in the procedure above. The conclusion drawn from any observa-
tions and the process of reasoning involved should also appear
in the note-book, and will be of assistance to enable the instructor
to offer helfpul criticism. The most important object in a begin-
ning course in organic analysis is not so much the correct solution
of a given unknown which is the invariable result when com-
paratively simple unknowns are met, but the manner in which the
conclusion is derived. The student is not limited to the above
procedure in connection with all of his identification work in the
laboratory. In fact, he is asked to apply the directions only to
the first three simple unknowns, after which he is urged to study,
apply, and compare the procedures for identification as given in
other manuals, such as Clarke, Mulliken, and Rosenthaler.
CHAPTER VII
DETERMINATION OF PHYSICAL CONSTANTS AND
ANALYSIS FOR THE ELEMENTS
The steps essential to a systematic and successful identification
of an individual organic compound have been outlined briefly in
the preceding chapter. The term pure organic compound has been
intentionally avoided, since the analyst seldom meets such indi-
viduals.
The identification work in connection with this course will
consist of the identification of six or eight individual compounds
and subsequently some experience will be offered also in connec-
tion with the separation of mixtures. (Chapter XII.) Some of
the individual compounds may, however, require purification;
it will be advisable never to assume unreservedly a high degree of
purity but to approach each problem in an unorthodox attitude
and draw every conclusion in accordance. In this course " con-
stant boiling-points " and " sharp melting-points " will not be
taken as absolute criteria of purity; such constants justify sub-
mission of the unknown to the regular identification procedure
but subsequent tests (solubility, class reactions, preparation of
derivatives, etc.), will provide the necessary supplementary evi-
dence regarding purity. An actual example taken from the labora-
tory will illustrate this point.
A given unknown ^ appeared to be pure since the boiling-point
was fairly constant at 198°-199° while preliminary examination
and solubility test gave no indication of a mixture. By means of
the usual systematic tests the unknown was limited to the class of
primary aromatic amines, and consultation of the tables (page
200) suggested the following individual possibilities:
^ The sample was purchased on the market as o-toluidine of special purity.
Ill
112
QUALITATIVE ORGANIC ANALYSIS
B.p.
199°
200°
203°
205°
o-Toluidine Acetyl Dcr. m. 112° Benzoyl Der. m. 142°
p-Toluidine
m.p. 42° Acetyl Der. m. 148° Benzoyl Der. m. 158°
7w-Toluidine Acetyl Der. m. 65° Benzoyl Der. m. 125°
^Menthylamine
Since p-toluidine is a solid, it appeared to be excluded from the
list of possibilities. However, the acetyl derivative of the unknown
melted at 120° after one crystaUization and at 146-7° after the
second and subsequent purifications. This agreed with the value
for the acetyl derivative of p-toluidine; consequently a benzoyl
derivative was prepared. It was found to melt at 157° and the
mixed melting-point with known benzoyl-7>toluidine showed an
unchanged value. The difficulty was easily explained in the light
of these numerical data. The unknown, although of constant
boiling-point, was a mixture of toluidines, the solid para compound
being dissolved in the liquid ortho isomer. The acetyl derivative
was a mixture, but after several crystallizations from water the
more soluble ortho compound was removed and pure acet-p-
toluidine remained.
Manipulation of Small Amounts of Material. — When prelim-
inary work indicates that an unknown is of questionable purity, it
will be necessary to subject the com-
pound to additional purification.
Solids may usually be subjected to
crystallization from suitable sol-
vents, and liquids to fractionation.
Distillation with steam, sublimation,
and fractional precipitation are also
occasionally of value. The methods
used in previous organic laboratory
work can therefore be applied but
with suitable modifications to adapt
the procedures to manipulation of
relatively small amounts of material
in such a way as to prevent mechani-
cal losses.
In general, it is necessary to
use miniature apparatus. Many
of the operations ordinarily requir-
ing a separatory funnel can be
carried out efficiently (see Fig. 3), by means of the suction pipette.
<-^
©
Fig. 3.
DETERMINATION OF PHYSICAL CONSTANTS
113
Fig. 4.
The latter is made by drawing out one end of an ordinary
thin-walled glass tube and fire-polishing the
ends. It should be *of about 2 cc. capacity,
graduated at ^ cc. intervals, and equipped
with a piece of narrow gum tubing of suffi-
cient length that the tip of the pipette may
be held at eye-level during the manipulation.
The suction pipette is used not merely for
separating liquid layers but also for measuring
definite amounts of liquid organic reagents
used in various tests. The method of pour-
ing a portion of unknown or of an organic
reagent from a test-tube or bottle and
guessing at the quantity of material used,
results not merely in a waste of material
but also in poor results. Solid reagents are
weighed on micro-platform or on horn-pan balances which permit
rapid weighing with an accuracy of about 0.02 g.
For suction filtration, particularly
when the liquid is to be saved, the
apparatus shown in Fig. 4 is of
value.
Fractionations of small amounts
of liquid that require a fractionating
column are often very troublesome.
The combined flask and column
shown in Fig. 5 will often solve such
a difficulty.
The examples given above will
suggest a few of the directions in
which effective work involving small
quantities of material may be con-
ducted without serious losses; ex-
cellent directions for the manipula-
tion of small amounts of material in
connection with the preparation of
derivatives will be found in Mulli-
ken. Vol. I. When only extremely
small quantities of material are avail-
able, resort must be had to the methods of micro-analysis.
114 QUALITATIVE ORGANIC ANALYSIS
I. MELTING-POINTS
The ignition test will determine the advisability of taking a
melting-point. Obviously it will be a waste of time to attempt
taking melting-points on compounds which show no evidence of
melting definitely when heated on platinum-foil. Most salts of
acidic organic compounds with metals do not possess definite
melting-points and the constants of the members which do melt
before undergoing decomposition are not always available in the
literature. Many hydrochlorides of organic bases possess reliable
melting-points, but in general this class of compounds shows too
little variation in melting-points among the individual members.
Compounds of high molecular weight often undergo decompo-
sition before melting, and others may sublime. Many compounds
undergo appreciable decomposition at temperatures near the
melting-point and therefore the value obtained may vary some-
what with the rate of heating. This is noticeable with certain
dicarboxylic acids (which ones?) and especially with polyhydroxy
compounds, as with the sugars and some of their derivatives. A
few types show two melting-points. Explain how this is possible.
A sharp melting-point is not necessarily a criterion of purity.
A more reliable criterion is obtained by fractionally crystallizing
a compound from two solvents of widely different types and
redetermining melting-points of the various fractions. Small
amounts of fusible impurities usually lower the melting-point.^
Mixed Melting-points are of Special Value in Qualitative
Organic Analysis. — A small amount of the substance to be tested
is intimately mixed with an equal portion of the known compound
and the melting-point determined. If the two samples are iden-
tical, the melting-point will be unchanged, whereas the mixing of
two different compounds possessing the same melting-point will
usually, but not invariably, result in a different and usually a
lower melting-point.^
The melting-point of a crystalline substance is that tempera-
ture at which the solid is in equilibrium with the liquid phase.
The melting-points usually determmed in the organic laboratory
(and this is true also of most of the values recorded in the literature)
are not true but capillary melting-points.
iFor exceptions, see C. A. 14, 57 (1920); also Finlay: The Phase Rule
and Its Applications.
DETERMINATION OF PHYSICAL CONSTANTS
115
A small quantity of finely powdered solid material is placed in a
capillary tube, ^ Fig. 6, and heated in a sulfuric acid or oil bath as
indicated in Figs. 7 and 8. The open beaker method using a
stirrer is preferable. The part of the capillary tube containing
the substance should lie in contact with the bulb of the thermom-
eter. As the temperature of the bath approaches the melting-
point, the substance will often sinter and shrink from the walls of
the tube; occasionally softening is noted as the melting-point is
Fig. 6. — Actual Size.
approached; finally the material liquefies, sometimes gradually''
over a range of several degrees but more often quite sharply.
For example, a given unknown was observed to soften at 138°,
^ A light-walled glass tube 15 mm. in diameter is heated uniformly over
about 3 cm. of its length and drawn out into meter lengths of uniform bore.
The capillaries are then cut into convenient lengths, sealed at one end and
protected from contamination by storage in a dry stoppered test-tube. For
a determination of melting-point a 5 mm. layer of material is placed in a tube.
Vibration of the latter by means of a file will be of aid in causing the material
to settle rapidly to the bottom of the tube in a compact layer.
When a sulfuric acid bath is used, the capillary tube (if of imiform bore
and of sufficient length as shown in Fig. 6) will adhere to the thermometer
by capillary attraction. When an oil-bath is used, a small rubber band may
be used to fasten the capillary.
116 QUALITATIVE ORGANIC ANALYSIS
actual liquefaction was noted at 142° and the substance was com-
pletely melted at 142.5°. It is customary to record these data in
the following manner: m.p. 142-142.5° c. (softens at 138°). The
letter c indicates that the thermometer reading has been corrected ^
for stem exposure.
In general, it is advisable to make two determinations; in the
first one the bath may be raised quite rapidly and the melting-
point located within a range of about 5°. The bath is then
allowed to drop 10°-20° below the melting-point, a new charged
capillary tube attached to the thermometer, and the temperature
of the bath raised gradually and uniformly (stirring). As the
actual melting-point is approached, the temperature of the bath
should be raised at the rate of about 1° per five to ten seconds.
Question: A sample of o-phthalic acid was found to melt at 185 "-lOS"
when the capillary tube was placed in the cold bath and the temperature
gradually raised to the melting-point. The bath was then allowed to cool
to 175° and the melting-point of a second portion determined. The second
value was found to be 200°-205°. Explain these variations.
For melting-point determinations in the neighborhood of 300",
it is advisable to use either (a) a sulfuric acid bath containing about
40 per cent of potassium acid sulfate or (6) a cotton-seed oil bath
containing about 10 per cent of beeswax. In all work of this kind
even at low temperatures, particularly where sulfuric acid is used,
special precautions must be observed to prevent accidents. The
work at the higher temperatures must be conducted under a hood.
Many organic compounds that are met in the form of liquids may
be solidified by chilling in a freezing mixture. In such cases true
rather than capillary melting-points are determined. A 1 or 2 cc.
portion of the liquid is placed in a test-tube and a thermometer
placed directly in the liquid. The tube is then placed in a freezing
^ The formula often used is: Correction = +N(< — /')0 000154; in which
N represents the number of degrees on the stem of the thermometer from the
surface of the bath to the temperature read, / the temperature read, I' the
average temperature of the exposed mercury column, and 0.000154 the
apparent coefficient of ex-pansion of mercury in glass.
Since this correction is of questionable accuracy under the usual labor-
atory conditions, it is advisable for each student to calibrate a 360° thermom-
eter against a standardized laboratory thermometer. The two instruments
are placed side by side in the bath shown in Fig. 7 and comparisons made
over the entire temperature range at 25° inter\'als. It is essential in this
case to use a slightly larger bath and also a stirrer.
detehmination of physical constants 117
mixture and the walls of the tube scraped with the tip of the ther-
mometer. Very often persistent supercooling will be noted but
after a compound has once been solidified an accurate melting-
point value may be determined,
II. BOILING-POINTS
The usual method of determining boiling-points when appre-
ciable amounts of liquid are available is to actually distill a 5-10 cc.
portion of the material. This procedure furnishes not merely a
boiling-point but also something of more value in ordinary work,
namely, a boiling-point-range. The operation differs from the
usual distillation procedure only in the use of smaller amounts of
material and miniature apparatus.
The small 10 cc. flask is placed upon a square piece of asbestos
board which contains a perforation of about 2 cm. diameter. A
small flame is used so as to prevent superheating, but care must
be taken to prevent fluctuations in the thermometer reading due
to variable cooling of the vapors in the neck of the flask. The bulb
of the thermometer should be placed near the outlet of the flask
and naturally the temperature reading is not taken until the
mercury of the thermometer has been given time to come to the
temperature of the vapor. Because of the small amount of liquid
distilled it is necessary to distill slowly. The type of condenser
used (air or water-cooled) depends upon the boiling-point of the
liquid being distilled, but should be of small size so as to prevent
excessive loss of the distillate. Very high-boiling liquids may be
collected directly into a test-tube receiver since the quantity of dis-
tillate is so small. When some suggestion is at hand in regard
to possible decomposition upon distillation, it is necessary to test a
cubic centimeter of material by heating in a small test-tube before
subjecting the main portion of the sample to a high temperature.
Substances which boil with decomposition under ordinary
pressure may usually be distilled under diminished pressure.
Usually this will not be necessary when dealing with an individual
compound since other constants and particularly the constants of
derivatives may be relied upon. For the separation of certain
liquid mixtures which contain ingredients that may be distilled
only under reduced pressure, it is necessary to resort to this modi-
fied method.
118
QUALITATIVE ORGANIC ANALYSIS
!^
The boiling-points of small portions of material (about I cc.)
may be determined in the apparatus shown in Fig. 9. The test-
tube and attached thermometer are heated in the usual melting-
point bath equipped with a stirrer. The test-tube contains a
glass tube, 4 mm. in diameter, which acts as a condenser; the
lower end (8 mm.) is sealed off but is
open at the end and immersed to a
depth of about 4 mm. in the liquid
under examination. The bath is heated
to slightly above the boiling-point of
the unknown until the last traces of
air have been driven from the lower
open end of the condenser tube. As
the temperature of the bath is now
slowly lowered it is noted that vapor
bubbles cease to emerge from the lower
end. Soon after this, the liquid tends
to slowly draw back into the tube.
The temperature at which the level
of the liquid within the tube is the
same as that outside is taken as the
boiling-point; i.e., the temperature at
which the liquid is in equilibrium with
the vapor.
In the hands of the beginner, the
method described above is not par-
ticularly reliable and it is therefore
necessary to test out the apparatus on
several compounds of known boiling-
points before relying upon the results obtained with unknown
compounds. The method i» adaptable only to work with pure
compounds and is therefore of limited value.
m
Fig. 9.
III. SPECIFIC GRAVITY
The density of liquid unknowns is determined most conveni-
ently by means of the specific gravity tube ^ shown in Fig. 10.
The tube is standardized by weighing it, first empty and again
^ These tubes are easily prepared by sealing one end of a thick-walled
glass tube of 3-mm. diameter and blowing a bulb of the form shown.
DETERMINATION OF PHYSICAL CONSTANTS 119
after it is filled with distilled water and the level of the latter
adjusted to the mark at a temperature of 20°. The dry tube
should be kept in a clean box with a card showing (a) its weight
filled with water at 20°, and (6) its weight when empty. In all
subsequent work one filling and weighing will be sufficient to
determine the specific gravity of the unknown.
In determining the specific gravity of an unknown, fill the tube
to slightly above the etched mark by means of a glass tube drawn
to a capillary of such diam- ^ ^^
eterthat it may be inserted ( ' (i ()
through the narrow neck
to the bottom of the tube. Fig. 10.— Actual size for tube of about
Place the tube and its con- 0.6 cc. capacity.
tents in an upright position
into a small beaker containing water at 20°. After ten minutes,
adjust the level of the liquid to the reference mark by means of
the capillary pipette, dry the tube, and weigh it. The specific
.,20.
gravity (aoo) will be equal to the weight of the sample divided by
the weight of the same volume of water. Weighings are taken
only to the third decimal place. ^
Before returning the tube to the box, the liquid is recovered by
withdrawing it with the capillary pipette and the tube is cleaned
first with alcohol and with ether. Finally, the ether vapor is
removed by drawing, not blowing, air through the pipette.
OTHER PHYSICAL CONSTANTS
Melting-point, boiling-point, and specific gravity represent the
three constants of organic compounds that are determined as a
routine procedure. Other constants, such as refractive index,
optical rotation, quantitative solubility determinations, etc., are
applied in later stages of an analysis if found to be of sufficient
importance to aid in the differentiation between a number of pos-
sibilities. Molecular weight determinations are required only
in exceptional instances.
The Index of Refraction (n) is the ratio of the sine of the
angle of incidence to the sine of the angle of refraction (ratio of the
' Greater accuracy is not justified because of the questionable purity
of many unknowns. A temperature of 20° has been chosen not only because
it is near room temperature but also because many of the results in the liter-
ature have been reported at 20°.
120 QUALITATIVE ORGANIC ANALYSIS
velocity of light in air to that in the substance under examination) ;
it may be read directly by means of the Abbe refractometer, which
is the most convenient form of instrument for use in the quahta-
tive laboratory.
The Specific Rotation of an optically active compound is
determined by means of the polariscope. The specific rotation
a observed by sodium light at the temperature t is calculated
according to the formula :
100 a
H>
IXc
where a represents the observed angle of rotation (either + or — ),
I the length in decimeters of the column of liquid in the polariscope
tube, and c the number of grams of active substance in 100 cc. of
solution.
Molecular Weight Estimations may be made by a variety of
methods, the most important of which are the cryoscopic, the
ebullioscopic, and the vapor density methods. The first mentioned
method, based upon the accurate determination of the depression
of the freezing-point of a known solvent following the introduction
of a known weight of solute, is generally applicable and is used most
often by the organic chemist. The molecular weight {M) is cal-
culated according to the formula:
A
where c is a constant for the particular solvent used, p is the num-
ber of grams of the unknown per 100 g. of solvent, and A is the
depression of the freezing-point. A similar formula is used for
calculation of molecular weights based upon the elevation of the
boiling-point of a liquid due to the presence of a non-volatile dis-
solved substance. In the latter instance, the constant c' is sub-
stituted for c and A now represents the rise in boiling-point.
In connection with the identification of organic compounds
that have been previously characterized, the estimation of equiva-
lent weights is of more value that that of actual molecular weights.
This is done by estimating quantitatively some typical element or
reactive group. Such methods are discussed in Chapter XI.
The Value of Physical Constants when Used in Connection
with Class Reactions. — Unnecessary group tests are often applied
ANALYSIS FOR THE ELEMENTS 121
by the beginner when the desired specific information may be
gained from a consideration of the physical constants of an
unknown. Examples will be given from among the halogen
derivatives of the hydrocarbons but similar applications may be
made to other classes of compounds.
When a halogen compound possesses a boiling-point below
125° at 760 mm., the unknown cannot be an aromatic compound.
When an organic bromine derivative boils below 150°, it
must be aliphatic. Similarly, an iodine derivative with a boiling-
point below 180° must be aliphatic. In these instances, sulfona-
tion and other tests for differentiation between the aliphatic and
aromatic series are superfluous. (Note that the above statements
are not limited merely to halogen derivatives of hydrocarbons, but
apply to all organic halogen compounds.)
When an organic chlorine derivative boils below 175° but
possesses a specific gravity of more than 1.4^0°, then it is an ali-
phatic compound; similarly, bromine compounds boiling below
200° but possessing specific gravities of more than 1.6-^° must
be aliphatic compounds.
Explain the statements given above and be prepared to cite evidence
either for or against these generalizations. Why would it be unsafe to base
analogous statements upon melting-point data?
ANALYSIS FOR THE ELEMENTS
Test the unknown for an inorganic residue by igniting a small
amount of material in a crucible. If a residue is left, examine
it by the usual methods used in inorganic qualitative analysis.
Residues from calcium and barium salts will be detected readily.
Sodium and potassium salts will leave fusible residues of the cor-
responding carbonates which may be overlooked by a careless
observer. Some inorganic materials may prove to be volatile
(give examples), whereas others may leave black residues of either
oxide or reduced metal (give examples). Usually, however,
black residues are due to the presence of carbonaceous matter
which is removed only upon prolonged heating.
Many fairly pure compounds leave a trace of residue upon
ignition and in cases of doubt this may be weighed in order to
determine whether it represents an appreciable portion of the total
weight.
122
QUALITATIVE ORGANIC ANALYSIS
ANALYSIS FOR S, N, CI, Br, AND I
Very few organic compounds contain these elements in such a
form that they may be tested directly by the methods of ion analy-
sis; fusion with metallic sodium, however, decomposes the organic
substance according to the following scheme :
heat
[C, H, O, N, S, CI, Br, I, etc.] + Na^ >
Na2S, NaCN, NaCl, NaBr, Nal, Na20, C, CO2, H2O, etc.
In the fusion mixture, sulfur may therefore be detected by the
usual tests for sulfide ions, nitrogen by the tests for cyanide, and
the halogens by the usual familiar methods.
Rarely, when sulfur and nitrogen are both
present, a trace of NaCNS may also be
formed and may be detected by the red
coloration given with ferric chloride after
acidification.
Directions for the Sodium Decomposition.
— Place a piece of clean metallic Na the size
of a very small pea into a 2-inch test-tube
suspended through a piece of asbestos board
as shown in Fig. 11. Add a little of the
material (one drop of a liquid or a few frag-
ments of a solid) and heat the tube with a small
flame, not only until the sodium melts, but
until the vapors of sodium form a layer | inch
in height. Allow three drops of the unknown, if
liquid, or an equivalent quantity of fragments,
if solid, to fall at intervals of one or two seconds
directly upon the fused sodium without
touching the sides of the tube. (Precaution!) Heat the reaction-
mixture strongly so as to oxidize most of the residual sodium as
well as to remove volatile organic decomposition products. By
means of a pair of tongs, lower the hot tube into a small beaker
containing 10 cc. of water. (Special precaution!) The tube is
merely touched to the surface of the water and then raised out of
the liquid but held in the beaker in such a manner that the heavy
glass of the beaker will be between the tube and the ej^es of the
operator. Momentary contact with water will cause the hot tube
¥
Fig. 11.
ANALYSIS FOR THE ELEMENTS 123
to crack and traces of unreacted sodium will be destroyed by spon-
taneous burning without the dangers of a hydrogen explosion.
(Demonstration by instructor.) The cooled tube is now tapped
against the inner side of the beaker and the lower cracked part
allowed to drop into the water. The solid particles are broken
up with with a stirring rod, the solution heated to boiling and fil-
tered. The filtrate, which should be colorless, is reserved for the
subsequent tests.
A. Sulfur Test. — To 1 cc. of the filtrate made slightly acid
with acetic acid, add a few drops of lead acetate reagent. A
black precipitate of PbS shows the presence of sulfur.
B. Nitrogen Test. — Boil 3 cc. of the alkaline stock solution
for two minutes with 5 drops of FeS04, and 1 drop of FeCls solu-
tion. Cool and acidify carefully with HCl. The precipitate of
iron hydroxide should dissolve readily, otherwise the solution
should be warmed very gently. A clear yellow solution indi-
cates a negative nitrogen test; a blue precipitate indicates a posi-
tive test. A blue or greenish-blue solution suggests the presence
of nitrogen but indicates that the original sodium decomposition
may have been poor. The precipitate of Prussian blue shows up
best when it is collected and washed upon a white filter paper.
If iodine is present, the filter is washed with alcohol to dissolve
out the iodine. In the presence of sulfides, it wiU be advisable
to add enough FeSOi solution to completely precipitate the sulfur
ions, filter off the FeS, and proceed as above.
Write equations illustrating the formation of Prussian blue.
C. Tests for Halogen, (a) General Test. — Acidify 2 cc. of
the stock solution with dilute HNO3 and boil well to expel any
HoS or HCN if present. Add AgNOs solution. A precipitate
denotes the presence of halogens. Also apply the Beilstein copper-
oxide-wire test to the original unknown.
(6) Tests for Bromine and Iodine in the Presence of Each
Other and the Other Halogens. — Acidify 2 cc. of the stock solution
with H2SO4 and boil gently to drive off H2S. Add not more than
J cc. of carbon tetrachloride and finally a drop of a solution of
freshly prepared chlorine water. Shake after the addition of each
drop. If iodine is present, the carbon tetrachloride will be colored
purple. Continued additions of chlorine water will cause the
iodine color to disappear, due to the formation of the iodate, and
if bromine is present the carbon tetrachloride will become colored
124 QUALITATIVE ORGANIC ANALYSIS
brown at this stage. Be careful to add the chlorine water slowly
or these colors may be missed.
(c) Tests for Chlorine in the Presence of Other Halogens. —
Acidify 2 cc. of the stock solution with a few drops of acetic acid,
add excess of Pb02, and boil gently until all the Br2 and I2 are
liberated. Dilute and test for CI by the addition of HNO3 and
AgNOs. A faint chlorine test may be due to a trace of chlorine
either in the metallic sodium or in the glass of the test-tube used
for the fusion, or in the Pb02. A blank test should be run.
Beilstein CuO Test for Halogen. — This test is apphed to the
original unknown. A copper wire of small diameter is heated in
the flame until no trace of green color is noted. The cooled wire is
dipped into a small portion of the substance and again heated. A
green color imparted to the flame, sometimes only a momentary
flash, is due to the volatilization of copper halide.
The above tests are the only ones appUed in a routine way to the unknowns
met in the present course. Carbon and hydrogen may be detected by heat-
ing the substance in a dry test-tube with ignited CuO and identifying the
moisture and carbon dioxide generated. Such a test is usually superfluous,
since abundant amounts of elementary carbon may be observed in the sodium
decomposition reaction, and special tests for hydrogen are unnecessary for
the purposes of identification of unknowns .
Phosphorus may also be detected in the filtrate from the sodium decom-
position, provided that a 1 cc. portion of the filtrate be oxidized by boiling
with a little concentrated nitric acid and subsequently tested with ammonium
molybdate reagent. A more reliable test which is applicable also to quan-
titative work consists in fusing the organic compound (if non-volatile) with
sodium carbonate and a small amount of potassium nitrate in a nickel cru-
cible. The melt is dissolved in acid and tested with molybdate reagent in
the usual manner.
The Carius sealed tube method is capable of yielding excellent results but
is ill-suited to routine work because of the time factor. In special instances,
however, it may be necessary to apply the method which with slight modi-
fication is applicable to the quantitative as well as qualitative estimation
of a variety of elements. A sample weighing 0.1 gram is heated in a sealed
bomb tube with 1 cc. fuming nitric acid (sp. g. 1.48) at a temperature of
200-300° during several hours. Sulfur, arsenic, and phosphorus are con-
verted into sulfuric, arsenic, and phosphoric acids respectively, chlorine and
bromine will be present partly as hydrochloric and hj^drobromic acids and
partly as free halogen, iodine as iodic acid, and metals will be present as
nitrates. Because of considerable pressure developed, great care must be
taken not only in heating but especially in opening the bomb-tube. The
detailed directions in Gattermann's Laboratory Manual should be studied
carefully before undertaking this dangerous operation.
ANALYSIS FOR THE ELEMENTS 125
A satisfactory method for treatment of organic arsenic consists in digestion
with sulfuric acid (in the presence of starch) by analogy to the Kjeldahl
method for nitrogen. Qualitatively the arsenic may be detected as sulfide
and quantitatively by iodimetric methods. (J. Chem. Soc. 109, 1356 (1916)).
The Marsh test serves for the detection of traces of arsenic.
Mercury in organic combination may often be converted into inorganic
form by digestion with hydrochloric acid, filtration from insoluble impurities
and precipitation with hydrogen sulfide. See also Whitmore: Organic Com-
pounds of Mercury, A. C. S. Monograph, pp. 361-367 (1921).
For references concernmg these and other specialized tests the list men-
tioned at the end of Chapter V should be consulted.
CHAPTER VIII
LABORATORY WORK ON THE SOLUBILITY BEHAVIOR
OF ORGANIC COMPOUNDS
The analytical procedure presented in this course has been
systematized primarily on the basis of solubility behavior. Before
proceeding with the application of the scheme, it is advisable to
devote one or two laboratory periods to the study of the solubility
behavior of known compounds and to the comparison of predicted
solubility values with those actually determined experimentally.
Determine the solubility behavior of a number of typical
organic compounds, selecting members from various important
homologous series. (A suggested list is indicated on page 129.)
Test the solubilities in the following reagents:
1. Water.
2. Ether.
3. Dilute acid (5 per cent HCl).i
4. Dilute alkali (5 per cent KOH). Note odor of evolved
gases.
5. Cold concentrated H0SO4 ^ (if the compound is insoluble
in tests 1, 2, 3 and 4).
Solubility tests are applied at room temperature (20°-25°).
Observations of value may be made by determining solubility
behavior in hot solvents but for purposes of classification the
results obtained at room temperature arx the ones desired. The action
of hot acid or alkali will be studied subsequently in connection
with the homologous tests.
Amount of Material Required in Solubility Tests. — The quan-
tity of the unknown used in a solubility test will naturally depend
upon the amount available. Usually it is convenient to use 0.10 g.
1 Tests applied to any evolved gases are also of value. Caution must be
observed since poisonous products like hydrocyanic acid, carbon monoxide,
and cyanogen may occasionally be encountered.
126
THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 127
of a solid ^ or 0.2 cc. of a liquid for 3 cc. of solvent. The same
portion of substance may be used, however, in several solubility
tests and occasionally practically the entire quantity of material
may be recovered for use in subsequent work. When a particu-
larly rare substance is under investigation, correspondingly smaller
amounts of substance and solvent must be used and special
thought be directed to the question of recovery.
Solubility in Water and in Ether. — A 0.10 g. portion of a solid
unknown is treated with successive 1 cc. portions of water until
3 cc. have been added. If the compound does not dissolve in
the ratio of 1 : 20 or 25, it is designated " insoluble in water."
The substance if solid must be finely powdered so as to eliminate
the possibility of a verdict of insoluble when in reality a mechanical
difficulty is responsible for the decision. If the substance appears
to be insoluble, the suspension may be warmed gently. If solu-
tion occurs, the test portion is again cooled and shaken vigorously
to prevent supersaturation upon cooling.
When dealing with liquid unknowns, 0.2 cc. of the substance,
delivered from the graduated pipette, is added to 3 cc. of water.
In this case equilibrium is attained quickly and the substance is
called insoluble if it does not dissolve in the proportion of 1 : 10
or 15. The student should not be misled, however, by the presence
of a trace of insoluble impurity in an otherwise soluble substance.
Give a theoretical explanation justifying a different standard of
solubility for solid in comparison with melted compounds.
■ Whenever a compound dissolves in water, test the aqueous
solution with litmus paper. In the case of liquids that are not
completely miscible, note their specific gravities in comparison
with water and record this data in your notes (sp. gr. > 1 or < 1).
Solubility tests in ether are carried out in a manner analogous
to that described for the water solubility tests. Compounds
falling in the borderline between what has been arbitrarily desig-
nated " soluble " and " insoluble " should be sought in more than
one group of the solubility table ; often the substance will be found
classified in both places. The ether solubiHty test may often be
applied in conjunction with the tests in water, dilute acid, or
1 It is advisable to weigh this material to within 1 centigram. If this
is not done, the beginner is liable to use as little as 0.02 g. of a light fluffy
substance and on the other hand in dealing with heavy crystals a correspond-
ingly large error is hable in the opposite direction. Small trip balances
accurate to .01 g. should be available for this purpose.
128 QUALITATIVE ORGANIC ANALYSIS
alkali, provided that suitable recognition be given to the possible
reactions of the unknown with either acid or alkali.
Solubility in Dilute HCl. — In this test, it is advisable to utilize
the same portion of unknown used in the water test. The proper
amount of substance thus will be available, either dissolved or
suspended in 3 cc. of water. To this solution or suspension add
gradually with shaking ^ to 1 cc. of 20 per cent HCl. The final
solution thus will contain about 5 per cent of HCl. The acid is
added gradually (| cc. at one time) for the reason that certain
organic bases form hydrochlorides that are only sparingly soluble
in the excess of HCl. Such compounds may prove to be soluble
after j cc. of acid has been added but may be insoluble in the
excess.
Question. — An unknown is soluble in water but a precipitate is formed
when HCl is added. What can be predicted concerning the unknown?
Solubility in Dilute KOH.^ — The material used in the water
and in the acid solubility test may often be recovered and utilized
for solubility in dilute KOH. When dealing with substances
sparingly soluble in water (1 : 200 or less), it is convenient to use
directly the solution or suspension from the preceding test. The
acid solution is exactly neutralized by the addition of ^ to 1 cc. of
30 per cent KOH, cooled to room temperature, and a further quan-
tity (^ to 1 cc.) of KOH added gradually wdth cooling.
Nitrogenous compounds that are found to be soluble in water
but insoluble in ether should be tested for the evolution of ammo-
nia or volatile amines when treated with alkali. This test is
applied by placing a small amount of material on a watch-glass,
moistening with strong KOH and noting the odor. The beginner,
however, should not rely upon his olfactory sense for differentia-
tion between ammonia and the volatile organic amines.
Question. — An unknown is soluble in water but a precipitate is formed
when KOH is added to the aqueous solution. What can be predicted con-
cerning the unknown?
Solubility in Cold Concentrated H2SO4. — The sulfuric acid
test is of value in differentiating between Groups V and VI.
Compounds falling in Groups I, II, III, and IV, as well as indif-
' Potassium hydroxide is used here in preference to sodium hydroxide
because the sodium salts of certain organic acids and phenols are sparingly
soluble, particularly in excess alkali. Hydrochloric acid has been used in
preference to sulfuric for the reason that the hydrochlorides of organic bases
are often more soluble than the sulfates.
THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 129
ferent compounds containing N, S, etc., need not be subjected
to the test in so far as classification is concerned. Since
the test may give information of value apart from classification
data (evolution of gases, charring, production of color, etc.), it is
advisable to apply the test to each unknown examined. The
student must refrain from placing any special reliance upon the
numerous sulfuric acid color tests reported in the literature, since
these are often greatly modified by traces of impurities. The
test must be applied to the dry substance and cold concentrated
acid must be used. Liquid compounds in Group V will usually
dissolve quickly but solid compounds must be finely powdered
and may require several minutes for solution. The applications
and limitations of the test have been discussed in Chapter II.
The following compounds are suggested for solubility work.
All materials must be used sparingly.
Class
Hydrocarbons and
Halogen deriva- <
tives
Ethers
Esters
Anhydride
Acids
Saturated aliphatic
Aromatic
Unsaturated
AHphatic
Aromatic
Aliphatic (low mol. wt.)
Aromatic
Aliphatic (low mol. wt.)
Monobasic
Aromatic ■! Dibasic
Amphoteric
Ketones and AI- f Aliphatic
dehydes I Aromatic
Alcohols
Phenols
Nitro compounds
Nitrile
Individual selected
Ligroin
Ethyl bromide
Toluene
Bromobenzene
Amylene
Ethyl ether
Anisole
Ethyl acetate
Ethyl benzoate
Acetic anhydride
Acetic acid
Benzoic acid
Phthalic acid
AnthraniUc acid
Acetone
Acetophenone
Amyl alcohol
Ethyl alcohol
Benzyl alcohol
Phenol
/3-Naphthol
Nitrobenzene
Trinitrotoluene
Benzyl cyanide
130
QUALITATIVE ORGANIC ANALYSIS
Amines, Amides,
Imides, and
RingN
Sulfonic acids,
Salts, and Car-
bohydrates
Primary amines
Tertiary amine
Negatively substituted (amide)
Negatively substituted (imide)
Ring nitrogen
Aniline
Benzidine
Dimethyl aniline
Acetanilide
Phthalimide
Quinoline
Uric acid
Ammonium benzoate
Sodium benzoate
Sodium benzene sul-
fonate
p-Toluidine hydro-
chloride
I Sucrose
Supplement the above list with other typical compounds in
which you are interested and in each case compare your results
with the proposed solubility table at the end of this text. With
the aid of your instructor apply any additions and corrections to
this table. Do not proceed with laboratory work on identifica-
tion of unknowns until you feel confident in being able to predict
the solubilities of common organic compounds from the corre-
sponding formulas without resorting to actual laboratory test;
in other words, do not attempt to memorize any part of the Solu-
bility Table, but instead, know the generalizations upon which the
table is based.
Record solubility data in the following manner :
Solubility in
Solu-
bility
Group
Substance
Water
Dilute
HCl
Dilute
KOH
Cone.
H2SO4
Ether
Piperidine
hydrochlor-
ide
Phenyl sali-
cylate
Iso-amy 1
ether
m-Xylene —
+
(sp.g.<l)
(sp.g.<l)
+
+
(ammonia-
like odor)
+
Evolution
of HX
+
+
+
+
+
II
IV
V
VI
THE SOLUBILITY BEHAVIOR OF ORGANIC COMPOUNDS 131
Class-room Exercise. — Predict the solubility behavior of the
following compounds and be prepared to give in each case the
generalizations that lie at the basis of your answers.
CH2OH • (CH0H)3 • CO2H CH3 • CH2 • CO • CH3
CHs CH3 • (CH2)2 • CHCl • CO2 • (CH2)3 • OH
CH3\ I /H
CH3A ^Cl
.n/
CH3
^CH3
A
Br
Y
CH
[3
\A\NH2HBr
'^.— SOsNa
.CO2H
A H
CH3-
i
y
Ot
1
[
— CH3
,0H
CioH6<^
\CO2Na
V
NO2
C6H5CH2NHSO2C6H5
CeHs • C2H5
.CONH2
^^^OCHs
H
CsHii'C-CHs
1
N
\/
V(
Z=^
CHs^^
K/
\
CO2
•CHs
h
CHAPTER IX
LABORATORY WORK ON CLASSIFICATION REACTIONS
OF ORGANIC COMPOUNDS
In the following experiments, note carefully and record imme-
diately in your laboratory note-book all observations. Attention
should be directed especially to the following phenomena: Heat
effects, evolution of gases, changes in physical state (as for exam-
ple the conversion of a liquid to a solid), changes in solubility,
odors, color changes, etc.
All observations should be recorded in a permanent laboratory
note-book in the following manner:
(a) Observations,
(6) Reactions, written structurally,
(c) Conclusions.
Most of the experiments will consist of review work and
the reactions may be interpreted with the aid of the knowledge
gained in an elementary course in organic chemistry. The dis-
cussion in Chapters II, III, IV, and V will prove of value but the
student is expected to use also more advanced reference books.
Special emphasis will be placed upon the interpretation of the
reactions and the drawing of proper conclusions therefrom for the
purposes of organic analysis. In doing this for any one experi-
ment, it will often be necessary to utilize the results of other
experiments. The limitations of the tests and the exceptions
must be considered also in summarizing the results. No equa-
tions are required for experiment 1.
EXPERIMENT 1
Ignite on a strip of platinum foil over a small flame a small
amount (0.1 g.) of each of the following substances: (a) ligroin,
(6) toluene, (c) benzoic acid, (d) ethyl ether, (e) glycerol,
(J) ethyl alcohol, (g) trinitrotoluene, (h) amyl alcohol, (i) sodium
132
LABORATORY WORK ON CLASS REACTIONS 133
acetate, (j) barium benzoate, (k) ammonium benzoate, (I) starch,
and (m) urea.
Ignition is the first test applied to any unknown compound. If the com-
pound does not burn, what test should be applied? Note that certain organic
compounds burn with the production of a large quantity of soot, while others
burn merely with a luminous and sometimes with a non-luminous flame.
Can any generalization be drawn in regard to this behavior? Review the
results of the "burning tests" applied to methane, ethylene, and acetylene
in your elementary course. Note that the luminosity of the flame is some-
what dependent upon the quantity of material ignited.
Is a residue left on ignition? If so, is it fusible or non-fusible? Is it an
alkaline residue? Is it a carbonate? What is its color? Certain fusible
residues may form a thin glassy coating on the platinum and thus escape
detection by the beginner. Certain substances like starch may contain
sufficient impurity to leave a trace of residue. Usually such a residue is
easily differentiated from the amount left from the ignition of a typical salt.
If the compound is a solid, does it possess a melting-point? If so, predict
its melting-point to within about 25°. Most salts, and substances which
decompose or sublime without melting need not be subjected to actual
melting-point determinations .
The odor of compounds upon ignition is often suggestive to the experi-
enced analyst but care must be observed by the beginner because of the pos-
sibiUty of meeting toxic products.
TESTS FOR UNSATURATION
EXPERIMENT 2
Dissolve 0.2 cc. of amylene in 2 cc. of carbon tetrachloride and
add gradually a 5 per cent solution of bromine in carbon tetra-
chloride until a bromine color remains for about one minute.
Repeat this experiment using in place of amylene equal weights
of (a) phenol, (b) toluene, (c) allyl alcohol, (d) ethyl alcohol, (/)
maleic or cinnamic acids, (g) acetophenone. Because of the limited
solubility of cinnamic acid in carbon tetrachloride, 2 cc. of chloro-
form should be used as a solvent.
Why is carbon tetrachloride used as a solvent? How may one differ-
entiate between addition of bromine and substitution by bromine? Suggest
an experiment for determining whether addition is taking place as well as
substitution. Would aniline respond to this test? What classes of com-
pounds are readily substituted by halogens? Certain ethylene derivatives
add bromine very slowly.. May such exceptions be predicted?
134 QUALITATIVE ORGANIC ANALYSIS
EXPERIMENT 3
To 3 cc. of sodium carbonate (5 per cent) solution, add 0.2 g.
of amylene and then drop by drop with shaking a 2 per cent solu-
tion of potassium permanganate. Continue the addition until the
permanganate color is no longer destroyed.
Repeat this experiment using in place of amylene equal weights
of (a) toluene, (6) cinnamic or maleic acid, (c) benzoic acid, and
(d) salicylic acid or phenol.
In this experiment, it is necessary to differentiate between a slight reaction
due to impurities and a typical oxidation. For example, the impurities in
technical toluene may react with a few drops of the permanganate solution
but a reaction such as the oxidation of the side-chain to carboxyl would
require 30 cc. of reagent.
Does the permanganate test serve to detect those double unions that
react only slowly toward addition of bromine? Does the bromine test (Exp.
2) serve to modify conclusions drawn from Experiment 3?
Test also benzaldehyde, acetone, glycerol, and ethyl alcohol.
Under what conditions may copper acetylide be prepared? Is the for-
mation of explosive metallic derivatives typical of all tri-bonded compounds?
SATURATED HYDROCARBONS
EXPERIMENT 4
To ^ cc. of cyclohexane add 1| cc. of 20 per cent fuming
H2SO4. Mix by shaking at first gently and then more vigorously.
Allow the mixture to stand for several minutes to determine
whether solution has taken place. Repeat the experiment using
in place of cyclohexane (a) toluene or benzene, and (6) purified
ligroin.
The sign of reaction is the generation of heat and complete solution of
the compound without excessive charring. Occasionally it is desired to sepa-
rate the sulfonation product. This may be done by pouring the reaction
mixture into 10 cc. of water, filtering (from what?), and saturating the filtrate
with NaCl. Why is the above test not applied when the unknown dissolves
in cold cone. H2SO4 or when it imdergoes decomposition with cone. H2SO4?
Will the above differentiation apply also to the halogen derivatives of the
hydrocarbons? If in doubt, apply the test to ethylene bromide and bromo-
benzene respectively.
How may nitration be used to differentiate between aliphatic and aro-
matic hydrocarbons? How may the Friedel and Crafts Reaction be employed
for this purpose?
LABORATORY WORK ON CLASS REACTIONS 135
EXPERIMENT 5
To ^ cc. of benzene add 1 cc. of dimethyl sulfate. (Precau-
tion !) Repeat this experiment using in place of benzene an equal
volume of ligroin, petroleum ether, or kerosene.
The reagent must not contain free sulfuric acid. Because of the reported
toxicity of dimethyl sulfate, great care must be taken in handling it. The
products from the above experiments are poured into 1 : 1 ammonia water
to decompose the sulfate. If a drop of the ester touches the skin, the latter
should be washed with water and then with ammonia solution. The toxicity
of dimethyl sulfate may possibly be due to a methylation of haemoglobin.
HALOGEN COMPOUNDS
EXPERIMENT 6
To 3 cc. of alcoholic silver nitrate solution, add one drop of
benzyl chloride. After one minute heat the solution to the boiling-
point and observe.
Repeat the experiment, using in place of benzyl chloride one
drop of each of the following compounds: (a) benzoyl chloride,^
(6) bromobenzene, (c) ethyl bromide, and (d) chloroform or car-
bontetrachloride.
In actual identification work when elementary analysis has shown the
presence of halogen, this test should be preceded by the usual aqueous silver
nitrate test for ionic halogen. Occasionally also free halogen acid may be
present as an impurity.
Halogen compounds show a similar distinction when boiled with alcoholic
NaOH or KOH. How should this test be applied and why is alcoholic alkali
used in place of the aqueous solution?
EXPERIMENT 7
To ^ cc. of water, add cautiously a few drops of acetyl chloride.
Repeat the experiment, using in place of acetyl chloride two
drops of benzoyl chloride.^
Repeat both parts of the experiment, using | cc. of aniline in
place of water.
Would halogen compounds like ethyl bromide and benzyl chloride react in
a similar manner with aniline? What may be said about the relative reac-
' The vapors of benzoyl chloride are very irritating to the eyes. Destroy
all benzoyl chloride residues with cone. NH3 before pouring them into the sink.
136 QUALITATIVE ORGANIC ANALYSIS
tion velocities of alkyl halides in comparison with the reactivity of the acyl
haUdes? How will substitution by halogen affect the physical and chemical
properties of the various classes of compounds listed in the solubility table?
ALCOHOLS, PHENOLS, ACIDS, ETC.
EXPERIMENT 8
Add small slices of metallic sodium to 1 cc. of pure amy]
alcohol until no more dissolves. Cool the solution. Repeat the
experiment, using toluene, acetone, amyl ether, etc. How can
the test be applied to a solid substance?
Why does ordinary ethyl ether react readily with metallic sodium? Some
esters, ketones, amides, etc., also react. Write the equation for the reaction
between sodium and acetoacetic ester. Some high-molecular-weight com-
pounds that are also very feebly acidic may not dissolve in dilute aqueous
alkali. Such compoimds are often detected by dissolving in alcohol and
adding a little alcoholic sodium ethylate. (See Problem 3.) Tlie sodium
test is never applied to compounds in Group IV; its main use is in differenti-
ating between alcohols and ethers and, because of the interference by moisture,
it is of limited value.
Would halogen compounds ever interfere with the sodium test? ,
EXPERIMENT 9
Add three | cc. portions of acetyl chloride to (a) 1 cc. of ethyl
alcohol and (6) to 1 g. of phenol. After one minute pour the mix-
tures separately into 5 cc. of water (Caution!). With the suc-
tion pipette, separate the reaction product from (b) and test its
solubility in dilute NaOH to determine whether the product is
still acidic.
Into a 2-oz. g.s. flask, place 2 cc. of ethyl alcohol dissolved in
10 cc. of water. Add 2 cc. of benzoyl chloride and 10 cc. of
20 per cent NaOH solution. Shake the mixture steadily for five
minutes.
What would happen if alcohol were omitted in the last experiment? What
would be the result if ammonia were present in place of alcohol? Would
phenols behave in a manner analogous to the alcohols?
Compare the results of this experiment with those obtained in Experi-
ment 7.
EXPERIMENT 10
Dissolve 3 drops of acetone in 2 cc. of water. Add j cc. of
NaOH, and then drop by drop a solution of iodine in potassium
LABORATORY WORK ON CLASS REACTIONS 137
iodide until a pale yellow color remains. When a substance does
not respond to this test at room temperature, warm the solution
to 60° and, if the iodine color disappears, add a few more drops of
iodine solution.
Repeat this experiment, using in place of acetone (a) ethyl
alcohol, (6) methyl alcohol (free from acetone), and (c) ethyl
acetate.
EXPERIMENT 11
Add a drop of ferric chloride to very dilute (about xV per cent),
aqueous solutions of (a) phenol, (6) resorcinol, (c) acetoacetic
ester, and (d) benzoic acid.
Some phenols which do not give a typical color with ferric chloride in
aqueous solution will do so in alcohol solution. Apply the latter test when
the results in water solution are negative.
EXPERIMENT 12
Add bromine water slowly to 5 cc. of dilute (about 1 per cent
or less) aqueous phenol solution, until a faint bromine color
remains. Repeat the experiment, using (a) aniline, (6) salicylic
acid, (c) resorcinol, and (d) p-nitrophenol.
This test has been used in connection with quantitative determinations
of certain phenols. Do you expect phenol ethers and acyl derivatives of
aromatic amines to act in the same manner?
Explain why the substituted aniline precipitates instead of remaining in
solution as the hydrobromide. Explain why a solution of sodium benzoate
may give a precipitate with bromine water in spite of the fact that benzoic
acid is only brominated at a fairly high temperature. What inorganic com-
pounds might decolorize bromine with the formation of a precipitate?
EXPERIMENT 13
Heat in dry test-tubes at a temperature of about 140° (using oil
or H2SO4 bath) for five minutes 0.2 g. of phthalic anhydride with
about 0.1 g. of (a) phenol, (b) resorcinol, and (c) a-naphthol, the
mixtures having been barely moistened with cone. H2SO4.
Add the fusions separately to 10 cc. portions of cold water and
neutralize the sulfuric acid with alkali.
Write the formulas for phenolphthalein in acid and in alkaline solution.
The production of fluorescein is often apphed also as a test for phthalic an-
138 QUALITATIVE ORGANIC ANALYSIS
hydride or phthalic acid. Succinic acid gives a similar color and this is true
also of certain other dicarboxylic acids possessing the two carboxyl groups
on adjacent C atoms. This test for phenols is not very general.
EXPERIMENT 14
Weigh on the accurate balance about two-tenths of a gram
of some organic acid (benzoic may be used). Titrate the sample
with standardized KOH solution (approx. N/10) using phenolph-
"thalein as indicator. When dealing with difficultly-soluble acids,
a few cubic centimeters of pure alcohol may be used as a solvent.
Calculate the neutral equivalent of the acid according to the formula:
Wt. of substance X 1000
Neut. equiv.
No. of cc. A^ alkali used'
Why must phenolphthalein, in preference to methyl orange, be used as
an indicator in the above experiment?
The neutral equivalent of an acid is equivalent to the molecular weight
divided by the number of acid groups titrated. What is the neutral equiv-
alent of citric acid? When an acid is imperfectly dried, will the neutral
equivalent be high or low?
Determination of the neutral eqiuvalent may be applied to most car-
boxylic acids. The presence of an aromatic amino group will not interfere
appreciably in the titrations, but aliphatic amino groups or the presence of
two aromatic amino groups will vitiate the results.
Hydroxyl groups and even the presence of a single phenolic group, as in
salicylic acid, will not interfere; e.g., ortho- and para-hydroxybenzoic
acids possess neutral equivalents corresponding to the molecular weights.
In general, the weakly acidic groups, like phenols, amides, and imides, give
abnormally high neutral equivalents. What indicator should be selected for
the titration of phenol? A strongly acidic phenol like s-tribromophenol
may be titrated quantitatively in alcoholic solution using phenolphthalein.
EXPERIMENT 15
Weigh on the horn-pan balance 1.0 g. of benzoic acid and 1.5 g.
of PCI5. Mix the materials in a dry test-tube and after sponta-
neous reaction has taken place warm the mixture gently so as to
dissolve the PCI5 completely. Pour the solution into 1 : 1 ammo-
nia water and shake the mixture.
This reaction is of considerable value for the preparation of derivatives
of many acids. Why is the method not applicable to hydroxy acids and
amino acids?
In general, it is advisable to remove the phosphorus oxychloride before
LABORATORY WORK ON CLASS REACTIONS
139
converting the acid chloride into the amide or anilide. This may be done
by distillation, (b. pt. 107°) or by the method mentioned in Chapter X,
pg. 150.
Acids that are aliphatic in nature, e.g,. butyric acid, cinnamic acid, hydro-
cinnamic acid, stearic acid, etc., may be converted into the corresponding
acyl chlorides by means of PCI3. In these instances, the acid chloride is rela-
tively insoluble in the by-product obtained and so may usually be separated
mechanically. Write the equation for the reaction.
The acid chlorides of hydroxy acids, Uke salicylic acid, may be prepared
by means of thionyl chloride (SOCI2).
PCI5 may act as a dehydrating agent upon certain organic compounds.
It also rearranges oximes into amides (Beckmann rearrangement.)
EXPERIMENT 16
Prepare about 150 cc. of an approximately 1 per cent to 2 per
cent acetic or propionic acid solution. Determine the total acidity
by pipetting off 10 cc. of the acid solution and titrating against
an approximately N/10 NaOH solution. Transfer 100 cc. of the
acid solution to a 250 cc. distilling flask and distill two portions of
10 cc. each, titrating them against the same NaOH solution.
Express the results of each portion of the distillate in percentage of
the total acidity of the 100 cc. used.
The Duclaux values expressed in percentages are as follows:
Formic
Acetic
Pro-
pionic
Butyric
Valeric
Iso-
Butyric
Iso-
valeric
Caproic
1. 10 cc.
3.95
6.8
11.9
17.9
24.5
25.0
28.7
33
2. 10 cc.
4.40
7.1
11.7
15.9
20.6
20.9
23.1
24
3. 10 cc.
4.55
7.4
11.3
14.6
17.0
16.0
16.8
19
Why is it unnecessary to use a standardized solution in the above titra-
tion?
An approximately N/10 solution is specified for the reason that the titra-
tion with 1 or 2 per cent acid solutions will require a convenient volume of
alkali for measurement in the burette.
The Duclaux method was proposed for quantitative work but has been
found of special value in connection with qualitative identification; e.g., we
note the following ratios between formic, acetic, and propionic acids: 4:7: 12,
ratios that are very much greater than those between the other physical
constants. Moreover, these acids are usually met in aqueous solutions and
140 QUALITATIVE ORGANIC ANALYSIS
the isolation of the anhydrous acids when present in low concentrations is
not a convenient operation.
The method is of importance not merely in connection with the identi-
fication of the eight compounds listed, but of any compounds that are readily
converted into these acids, e.g., the esters, amides, nitrites, salts, etc. It is
of course necessary that the total acidity of the solution be due entirely to
the volatile acid present and not to inorganic acid.
Outline the method for the identification of propionic acid in the solution
obtained by the alkali hydrolysis of propionamide.
ESTERS, ALDEHYDES, AND KETONES
EXPERIMENT 17
Determine the specific gravity at 20° of ethyl benzoate in one
of the small specific gravity tubes (cap. about f cc). See page
119, Fig. 10.
Dissolve 2 g. of sodium in 50 cc. of absolute alcohol and add
10 cc. of water after the sodium has dissolved. Withdraw a 10-cc.
sample from the homogenous solution for titration against N/4
acid for a determination of alkalinity. Place 40 cc. of the remain-
ing alkaline solution into a 100 cc. r.b. flask and transfer quan-
titatively from the specific gravity tube the weighed sample of
ester. This may be done by means of the capillary tube used for
filling the bulb. Small portions of the alcohol from the 40-cc.
portion of sodium ethylate solution are used for the purpose of
rinsing the tube.
Boil the ester solution under the reflux for one-half hour, cool
the contents of the flask, withdraw a 10 cc. portion of the alcoholic
solution and titrate the excess alkali against the N/4 acid. From
these values the saponification equivalent of the ester may be
determined by the use of a formula identical with that used for
calculating neutral equivalents of acids.
.^ ,. . , . Wt. of ester X 1000
feaponincation equivalent = ^r^^ ^-tt — ;-, — r-. 7.
No. cc. 01 N alkah used
The specific gravity tube is convenient for weighing samples intended
for quantitative saponification, since a single trip to the balance serves not
only for weighing the sample, but also for an accurate determination of the
specific gravity — a constant which may prove of value in connection with the
identification of the unknown.
For esters of low molecular weight, the quantity of sodium used must
be increased accordingly.
LABORATORY WORK ON CLASS REACTIONS 141
What values for saponification equivalent would be obtained from the
following compounds: Ethyl succinate, ethyl acid phthalate, benzaldehyde,
diamyl ether?
EXPERIMENT 18
Boil 2 cc. of ethyl benzoate in a small r.b. flask fitted with an
efficient reflux condenser, with 30 cc. of 25 per cent NaOH. An
ebullator tube will assist in preventing bumping. Saponification
will be complete after about thirty minutes, as will be indicated
b}'' the disappearance of the ester layer.
A. Examination of the Neutral Saponification Product. —
From the alkaline solution, distill about 4 cc. This fraction may
be used for the identification of the alcohol in the case of an
unknown. Water-soluble alcohols can be salted out with K2CO3,
B. Examination of the Acidic Saponification Product. — Cool
the residue in the distilling bulb and acidify with dilute H2SO4.
Benzoic acid will separate. Do not mistake a precipitate of sodium
sulfate for an organic acid. If in doubt, test the solubility of the
product in ether.
When an organic acid is soluble in water, other methods must be used to
separate it, viz., (a) ether extraction, (6) distillation, (c) as an insoluble
salt. When an ester yields an alcohol insoluble in water, the above indica-
tion of completeness of saponification cannot be used.
What kinds of esters yield alcohols that are non-volatile with water-vapor?
How will a lactone behave when subjected to saponification?
EXPERIMENT 19
To 1 cc. of acetone add 1 cc. of saturated sodium acid sulfite
solution and shake the mixture.
To 10 cc. of a 40 per cent solution of sodium acid sulfite, add
2\ cc. of ethyl alcohol. After several minutes, filter off or pour
the clear solution from the small quantity of precipitated salt.
This 20 per cent alcoholic solution of sodium acid sulfite is used
in the following tests:
To 1 cc. of the sulfite solution, add | cc. of acetone. Repeat
the experiment, using in place of acetone a \ cc. portion of (a)
benzaldehyde, (6) heptylaldehyde, and (c) acetophenone.
The sulfite addition products of aldehydes and ketones of fairly low
molecular weight are quite soluble in water. The progress of the reaction
may be nevertheless followed by the generation of heat. Most ketones of
high molecular weight do not react but the reaction is quite general for the
142 QUALITATIVE ORGANIC ANALYSIS
aldehydes. When deaHng with sparingly soluble aldehydes, particularly with
solids, a 0.2 g. sample or such a quantity as will dissolve in ^ cc. of alcohol,
may be added to 2 cc. of the sulfite solution. In this instance, the formation
of the precipitate may simply be due to the throwing out of the organic
compound because of dilution. If the initial compound is soluble in ether,
it may easily be differentiated from a sulfite addition product, since the latter
will be insoluble in ether.
EXPERIMENT 20
To 1 cc. of ammoniacal silver nitrate, add 1 drop of a 5 per cent
sodium hydroxide solution. If a precipitate of silver oxide or
hydroxide forms, add a drop of ammonia water so as to dissolve it.
Add 2 drops of acetaldehyde solution. Observe whether or
not reduction takes place. If the test-tube was previously
cleaned with hot NaOH solution, silver is usually deposited in
the form of a mirror.
Repeat this test, using in place of acetaldehyde, not more
than 2 drops of (a) acetone, (6) benzaldehyde.
Many compounds, organic and inorganic, in addition to aldehydes, may
reduce silver nitrate solution, e.g., the developers used in photography. (Write
the formulas for the common compounds used for this purpose.)
What explanation may be given for the failure of the aldehyde group in
glucose to react with the reagent? When dealing with water-insoluble com-
pounds ^ cc. of pure alcohol may be added.
EXPERIMENT 21
To 2 cc. of fuchsin-aldehyde reagent add 2 drops of acetalde-
hyde solution. Repeat the experiment, using in place of acetal-
dehyde 2 drops of (a) acetone, (h) benzaldehyde, (c) formaldehyde
solution, and (d) acetophenone.
In this experiment, the reagent should not be heated. Why?
To differentiate between formaldehyde and acetaldehyde, add 1 cc. of
25 per cent H2SO4 to each of the two test solutions.
The reagent is prepared by dissolving 0.2 g. Fuchsin in 100 cc. of hot
water, cooling, adding 2 g. of sodium bisulfite followed by 2 cc. of con. HCI,
and diluting to 200 cc.
Water insoluble compounds may be tested in the presence of alcohol
(1 cc.) provided that the latter is of sufficient purity so as to give no appre-
ciable color test.
EXPERIMENT 22
A. Water-soluble Aldehydes and Ketones. — Prepare some
phenylhydrazine solution by dissolving 1 cc. of liquid phenyl-
hydrazine in 3 cc. of 30 per cent acetic acid. Add ^ cc. of this
LABORATORY WORK ON CLASS REACTIONS 143
solution to a j-cc. portion of acetone dissolved in 3 cc. of water.
Repeat the experiment using | ce. of a water-soluble aldehyde in
place of acetone.
B. Water- insoluble Aldehydes and Ketones are best tested
in the following manner:
Dissolve ^ g. (or less) of the material in a few cubic centimeters
(usually 2 cc.) of ordinary alcohol. Now add water, drop by drop,
until the precipitate barely redissolves. If by mistake a slight
excess of water has been added, a few additional drops of alcohol
must be used. To the clear solution, add a quantity of phenyl-
hydrazine equal in weight to that of the unknown being tested.
Observe. If the solution remains clear for several minutes, add
1 drop of acetic acid and again observe. Test the following com-
pounds; (a) benzaldehyde, (6) acetophenone or benzophenone.
, Consider the relative advantages of hydrazones, semi-carbazones, and
oximes.
The hydrazones, when soUd, may be used as derivatives. The method
of testing under B usually leads to a product of higher purity. The time
required for the precipitation of the hydrazone is of value in predicting Some-
thing concerning the nature of the compound. The reaction is not very
accurate as a time test for the reason that supersaturated solutions may
be formed.
A trace of acetic acid catalyses the reaction. Many aldehydes give the
test readily, whereas ketones usually require the addition of a drop of acid.
This variation may possibly be due to the fact that most aldehydes contain a
small quantity of acid as an impurity. The ketones differ among themselves
in the time of precipitation.
CARBOHYDRATES
EXPERIMENT 23
A. Fehling's Solution Test. — Dissolve 0.2 g. of glucose in 5 cc.
of water. Add 5 cc. of Fehling's Solution and heat the mixture to
the boiling-point.
Repeat the experiment using in place of glucose 0.2 g. portions
of (a) lactose, (6) sucrose, (c) maltose, and {d) glycerol.
Dissolve 0.2 g. of sucrose in 5 cc. of water, add 2 drops of cone.
HCl and heat the solution in the steam-bath for five minutes.
Neutralize the free acid with alkali and apply the Fehling's Solu-
tion test. Sucrose hydrolyzes far more readily than do most
polysaccharoses.
144 QUALITATIVTC ORGANIC ANALYSIS
B. Osazone Formation. — Into a test-tube place 0.2 g. of a
given carbohydrate, 0.4 g. of phenylhydrazine hydrochloride, 0.6
g. of crystallized sodium acetate, and 4 cc. of distilled water.
Plug the test-tube with cotton and set it into a beaker of boiling
water. Note the time of immersion and the time of precipitation
of the osazone. To prevent supersaturation, the tube must be
shaken occasionally. Perform this experiment simultaneously
with the following carbohydrates: Glucose, sucrose, maltose, and
galactose. For time of osazone formation see page 155.
AMINES
EXPERIMENT 24
To a few drops of aniline, add a few drops of acetyl chloride.
Pour the reaction mixture into a cubic centimeter of water and
note the separation of the acetyl derivative of aniline. Repeat
the experiment with a few drops of dimethylaniline, in place of
aniline.
EXPERIMENT 25
To I cc. of aniline, add 5 cc. of 10 per cent alkali solution
and I cc. of benzenesulfonyl chloride. Warm the solution slightly.
After all the acyl chloride has reacted, cool the solution, filter off
any solid material, and acidify the clear filtrate. Agitate the
mixture to cause solidification.
HoAy may the benzenesulfonjd chloride test be used to dif-
"Terentiate between primary, secondary, and tertiary amines?
(Page 183.)
EXPERIMENT 26
The general method of diazotizating a primary aromatic
amine is as follows : Dissolve 1 mole of amine in 2| moles of hydro-
chloric acid. Cool to 0°. Add with stirring a cone, solution con-
taining 1.05 moles of NaNOo.
A. Dissolve 1 cc. of aniline in 3 cc. of cone. HCl and add
5 cc. of water. Cool the solution to 0°. Add 0.8 g. of NaN02
dissolved in 3 cc. of water. Apply the following tests to this
solution.
(a) Warm 5 cc. of the solution and note the liberation of gas.
The latter may be collected over cone. KMn04 solution to differ-
LABORATORY WORK ON CLASS REACTIONS 145
entiate it from oxides of nitrogen. Does the aqueous solution
give a phenol odor?
(6) Dissolve 0.1 g. of /3-naphthol in 1 cc. of 5 per cent NaOH,
and 4 cc. of water. Cool the solution to 10° and add 1^ cc. of the
cold diazonium solution.
B. Repeat the first part of the above experiment, using 1 g. of
N-monomethyl aniline in place of aniline. Note the separation of
the neutral nitroso compound (see page 64).
How may the diazotization of amines be used in qualitative organic
analysis to differentiate between various types of amines?
INDIFFERENT GROUPS (CONTAINING NITROGEN)
EXPERIMENT 27
A. Place a few crystals of ammonium benzoate on a watch-
glass and add a cubic centimeter of dilute alkali. Note the strong
odor of ammonia. Repeat the experiment with (a) urea, (6)
benzamide, (c) benzonitrile.
B. Place I g. of urea into a test-tube, add 2 cc. of 20 per cent
NaOH solution and boil the solution gently. Is ammonia evolved?
Repeat the experiment using in place of urea (a) benzamide, (6)
acetanilide.
What variation is noted in the ease of hydrolysis of various amides? A
part of this variation is due to differences in solubility of the organic com-
pound in the aqueous solvent used. The addition of 1 cc. of alcohol will
hasten the hydrolysis of water-insoluble compounds.
EXPERIMENT 28
A. To I g. of p-nitrochlorobenzene, add about 1 g. of granulated
tin and add in small portions a few cubic centimeters of 1-1 HCl.
Finally, heat the mixture gently. The nitro compound should
disappear completely. Pour the reaction mixture into about 10
cc. of water and add enough concentrated NaOH solution to
dissolve most of the precipitate of tin hydroxide at first formed and
distil a portion of the solution.
The product may be shown to be an amine by its solubility in dilute acid,
whereas the original nitro compound was insoluble in dilute acid. Which
amines will be non-volatile with water vapor? How may they be separated
from the tin-salt solution?
146 QUALITATIVE ORGANIC ANALYSIS
B. Into a small beaker, place 10 g. of iron powder and 5 cc.
of water. Add 1 cc. of 5 per cent HCl, and then 1 g. of p-nitro-
toluene. Stir the mixture with an iron spatula, warming gently to
start the reduction. The mixture should be in the form of a paste,
but to prevent solidification, ^-cc. portions of water may be
added. Finally heat in a water-bath for ten minutes with stirring.
The p-toluidine may be separated by adding 25 cc. of water and
distilling, or it may be separated by extracting the iron paste with
10 cc. of benzene. Note that the product is completely soluble
in dilute HCl, thus showing the absence of unchanged nitro com-
pound.
In the above reduction, difficultly-soluble nitro-compounds may react
slowly. In such instances, 2 cc. of alcohol may be added with the nitro com-
pound.
When p-nitrobenzoic acid is reduced by method B, how may the p-amino
acid be separated? What precautions must be taken because of the ampho-
teric nature of the amino acid?
EXPERIMENT 29
Place 1 g. of p-bromoacetanilide into a small round-bottom
flask and add 15 cc. of a mixture of equal volumes of sulfuric acid
and water. Boil under the reflux for one-half hour or until a por-
tion of the liquid on dilution does not give a precipitate of the
original substance. Dilute the hydrolysis mixture with about 50
cc. of water and precipitate the p-bromoaniline by the addition of
alkali.
Other reagents for hydrolysis are alcoholic alkali, alcoholic
hydrochloric acid, and strong acids under pressure.
Repeat the above experiment with (a) acetanilide, and (6)
benzamide, in place of p-bromoacetanihde.
Why does aniline fail to precipitate under the above conditions? How
may it be isolated as free aniline? As benzanilide? When benzamide is
used, why must the above criterion of completeness of saponification be
modified?
EXPERIMENT 30
Dissolve 1 drop of nitrobenzene in 1 cc. of 75 per cent alcohol.
Add a drop of NaOH solution and observe any color change. Add a
small fragment of 3 per cent sodium amalgam and note any color
LABORATORY WORK ON CLASS REACTIONS 147
changes. Does the amalgam liquefy more readily than in a blank
portion containing no nitro compound?
Apply this test to p-nitrobenzoic acid and to other nitro com-
pounds. If the unknown gives a very deep color with alkali
alone, the amalgam test should not be applied.
Certain nitro compounds in place of reduction to the azo stage under
the conditions of the above experiment, form only the Ught-colored azoxy
compounds. In some instances the azoxy derivative will be only sparingly
soluble in 75 per cent alcohol, and if so may be used as a derivative. Com-
pounds that dissolve in dilute alkah and which possess groups such as nitro,
nitroso, azo, etc., are very readily reduced to the corresponding amino com-
pounds by means of sodium hydrosulfite (Na2S204) in aqueous solution.
CHAPTER X
THE PREPARATION OF DERIVATIVES
Color reactions, the precipitation of an insoluble compound at
a given stage in the analysis, decomposition with certain reagents
— reactions that are often used with safety in inorganic anal3'sis
as final tests of identification, are applied in organic analysis only as
indications. Fortunately, in organic analysis, we may rely more
often for final identification upon a variety of physical constants,
not only of the unknown, but also of its derivatives. Very often
the elementary analysis of an unknown, together with a knowledge
of its solubility behavior and its class reactions, will have demon-
strated so clearly the type of compound dealt with that the physi-
cal constants of the unknown point to but one conclusion. Such
a circumstance, however, will seldom justify the failure to prepare a
suitable derivative and the identification of the latter by means of
its main constants. In this manner, the final possibility of error
may be obviated. For special cases, a series of derivatives may be
prepared and identified.
THE CHARACTERISTICS OF GOOD DERIVATIVES
1. The compound selected for a derivative should possess
physical and chemical properties which will enable an absolute
differentiation to be made between the individual possibilities.
2. Solid derivatives are preferable, because of the ease of ma-
nipulation of small quantities in preparation and purification, as
well as in the determination of constants.
3. The derivative should be prepared by a reaction which gives
a good yield of fairly pure product.
4. The derivative should be prepared preferably by a general
reaction which under the same conditions would yield a definite
derivative with the other individual possibilities. This will elim-
inate the necessity for a series of specific reactions.
148
THE PREPARATION OF DERIVATIVES 149
In connection with the apphcation of class reactions, sohd
derivatives are often obtained which may serve for use in the final
identification work. When this is the case, the time required to
complete an analysis will be materially lessened.
Occasionally a derivative is met which possesses a melting-
point close to that of the unknown; when the product of a reaction
melts close to or somewhat lower than the melting-point of the
original unknown, the student should question whether or not the
original unknown has been recovered, and he should apply addi-
tional tests as shown in the following examples:
A. Suppose it is necessary to differentiate between ortho and
meta nitrobenzoic acids. Is the amide a suitable derivative?
/M-nitrobenzoic acid m.p. 142° Amide m.p. 142°
o-nitrobenzoic acid m.p. 146° Amide m.p. 176°
In this instance, the amide may serve as a perfectly satisfactory
derivative, even though the unknown happens to be the meta
compound and the reaction product from amidation melts, let
us say, at 140-141°. It will be necessary, however, to demon-
strate that amide formation has actually taken place and that the
reaction product is no longer soluble in dilute alkali. In addition,
mixed melting-points of the original acid with some of the known
acid and of the derivative with known ?n-nitrobenzamide will
remove all doubt.
B. What derivative, satisfying all (and in particular the
fourth) characteristics of a good derivative, can be recommended
to differentiate between the four mono-chloro derivatives of tol-
uene?
o-Chlorotoluene b.pt. 159°
m-Chlorotoluene b.pt. 162°
p-Chlorotoluene b.pt. 162°
Benzyl chloride b.pt. 179°
The greater reactivity of the halogen in benzyl chloride will serve,
of course, to indicate side-chain halogen. By oxidation with alka-
line permanganate, all four individuals yield derivatives, and no
special modification of the oxidation method is required for the
individual compounds being oxidized. The melting-points of the
corresponding acids are 148°, 155°, 240°, and 122°, respectively.
The melting-points of the ortho and meta chlorobenzoic acids
150 QUALITATIVE ORGANIC ANALYSIS
(148° and 155°) lie too close together for absolute differentiation.
Accordingly, mixed melting-points are resorted to in order to
avoid the possibility of error.
THE CHOICE OF DERIVATIVES FOR SOME OF THE COMMONER
CLASSES OF COMPOUNDS
In the following discussion, the various types of derivatives
that are commonly used are mentioned in approximately the order
of their importance in the elementary work of this course. The
experimental procedures involved can be outlined in only the most
frequently occurring instances and the physical constants of only
a limited number of common compounds can be referred to within
the limits of the chapter.
Derivatives for Alcohols
1. Solid esters.
(a) Dinitrobenzoates.
(6) Benzoates.
(c) Acetates.
2. Urethanes.
3. Acid phthalates.
4. Oxidation products.
5. Halogen derivatives.
la. The 3, 5-dinitrobenzoates are convenient derivatives for
the water-soluble mono-hydroxy alcohols. MuUiken, I, 168.
In a small test-tube, mix 0.3 g. of 3, 5-dinitrobenzoic acid and 0.4 g.
of PCU. Warm the mixture slightly to start the reaction and when the rapid
reaction subsides, heat the mixture gently for about one minute, when the
evolution of HCl should cease. Pour the mixture upon a watch-glass (hood)
and after solidification, press the pasty solid upon a clay plate to remove the
POCI3. Place the powder into a dry test-tube, add 0.6 cc. of the alcohol,
stopper the tube loosely, and warm the reaction mixture on the water-bath
during about 10 min. Now add 5 to 10 cc. of water and filter after the prod-
uct has solidified. Transfer any solid material back to the test-tube and
crystallize the ester from about 5 to 10 cc. of ethyl alcohol-water mixture
of such strength that the ester will dissolve in the warm solution but will
crystalUze out on cooUng. Dry the material on a porous plate and determine
its melting-point.
In actual practice, the above experiment should be carried out by using
a known compound side by side with the unknown. The dinitro-benzoyl-
chloride is prepared in exactly double quantity, which, after drying, is divided
into two equal portions. Thus we may apply the method to a considerable
number of alcohols, the dinitrobenzoates of which may not be recorded in
the literature. Moreover, material is then at hand for the determination of
THE PREPARATION OF DERIVATIVES
151
mixed melting-points. The latter precaution is especially important, since
some of the above melting-points lie rather close to one another and the
boiling-points of some of the original material, especially of the higher alcohols,
may be lowered by the presence of moisture.
Alcohol
Boiling-point
Alcohol
Melting-point
3, 5-Dinitroben-
zoate
Melting-point
p-Nitrobenzoate
Methyl
Ethyl
Propyl
n-Butyl
Isobutyl
/3-Chlorethyl
7-Chloropropyl
Benzyl
66°
78°
97°
116°
108°
132°
162°
205°
107°
92°
73°
64°
83°
88°
54°
106°
96°
57°
Allyl alcohol may be converted into a dinitrobenzoate m. 48°,
but it should also be subjected to titration with bromine solution.
Isopropyl alcohol may be readily oxidized to acetone by means
of chromic acid and the ketone identified by the method given
below for acetone.
lb. Benzoates. — A few of the polyhydroxy alcohols (as for
example ethylene glycol and glycerol) are readily converted into
solid benzoates. In the reaction (Schotten-Baumann) an appre-
ciable excess of benzoyl chloride is used together with sufficient
NaOH (10 per cent) to neutralize the acid liberated as well as to
decompose the excess acyl halide. The method may be applied
also with other acyl halides (p-nitrobenzoylchloride, 3, 5-dinitro-
benzoylchloride, etc.) which are but slowly decomposed by water.
Alcohol
Ethylene glycol . . . .
Trimethylene glycol
Glycerol
Boiling-point of
Alcohol
197°
216°
290° d.
Melting-point of
Benzoate
70°
53°
72°
Ic. Acetates. — Certain high molecular weight alcohols, as
well as certain polyhydroxy alcohols, yield solid acetyl derivatives.
This tj^pe of derivative will be met again among the sugars.
152
QUALITATIVE ORGANIC ANALYSIS
The polyhydroxy-alcohols with four and six hydroxyl groups
react with benzaldehyde in hydrochloric acid solution to yield
sparingly soluble benzal derivatives, but, unfortunately, such
derivatives, as for example, those of erythrite, mannite, dulcite,
and sorbite, all melt in the neighborhood of 200°-220°.
2. Urethanes. — The phenyl urethanes are readily prepared by
combining phenyl isocyanate with a slight excess ^ of alcohol,
warming if the reaction is not spontaneous, and recrystallizing
the resultant urethane from a suitable solvent. The diphenyl
carbamates are prepared from diphenyl carbamyl chloride
(CgH5)2N • CO • CI but usually a fairly high temperature is required
to induce reaction. The phenyl urethanes of methyl, ethyl,
propyl, and butyl alcohol all melt within the range of 47° to 61°.
Alcohol
Boiling-point of
Alcohol
Melting-point of
Alcohol
Melting-point of
Phenyl Urethane
Benzyl
Phenyl Ethyl
Cinnamyl
Linalool
a-Terpineol
d-Borneol
204°
220°
257°
198°
217°
212°
33°
35°
203-4°
78°
79-80°
90°
65°
.113°
138°
3. Acid Phthalates. — The preparation of acid phthalates and
their use for differentiation between primary, secondary, and ter-
tiary alcohols has been discussed in Chapter III. n-Butyl and
benzyl alcohols, citronellol, geraniol, etc., are conveniently iden-
tified by this method.
4. Oxidation Products. — Aromatic alcohols possessing the
group -CH2OH may readily be oxidized to the corresponding acid.
Example: Benzoic acid from benzyl alcohol. The method is
similar to that to be outlined later in this chapter for the oxida-
tion of side-chains of aromatic hydrocarbons except that the
reaction is more rapid and the yields are higher.
5. Halogen Derivatives. — The replacement of the alcoholic
-OH group with either bromine or iodine is a typical reaction of
alcohols. Since the resulting derivatives are usually liquids, this
1 Reaction of phenyl isocyanate with water leads to the formation of the
water-insoluble diphenylurea.
THE PREPARATION OF DERIVATIVES
153
reaction is used only when considerable amounts of the unknown
are available.
Derivatives for Aldehydes and Ketones
1. Aryl hydrazones.
2. Semicarbazones.
3. Oximes.
4. Special condensation products.
5. Oxidation products.
1. Aryl Hydrazones. — The phenylhydrazones of aldehydes and
ketones of low molecular weight are generally liquids not adapted
for derivatives. By using p-bromo-phenylhydrazine, p-nitro-
phenylhydrazine, or /3-naphthylhydrazine, solid derivatives often
may be obtained. On the other hand, among the aromatic
compounds even the lower members yield solid phenylhydrazones.
Melting-point of
Phenylhydrazone
Furfural
Benzaldehj'de
97°
156°
103°
Acetophenone
The method of preparing phenylhydrazones is outlined in Chapter
IX, Exp. 22.
2 and 3. Semicarbazones and Oximes. — Semicarbazones and
oximes of aldehydes and ketones are generally white crystalline
solids, the former being usually the less soluble. Several of the low
molecular weight carbonyl compounds, however, yield liquid
oximes and it is best to use the semicarbazones for identification of
water-soluble carbonyl compounds and the oximes for water-
insoluble unknowns.
Preparation of a Semicarbazone. — 0.5 cc. of the unknown and 0.5 g. of
Semicarbazine HCl are dissolved in 5 cc. of water. About 0.7 g. of crystal-
lized sodium acetate is added and the solution set aside for an hour or more
in order to permit the semicarbazone to crystaUize. The derivative should
be recrystallized from a small portion of water.
Preparation of an Oxime. — Oximes of water-soluble carbonyl compounds
may be prepared in a manner analogous with that described for the semi-
154 QUALITATIVE ORGANIC ANALYSIS
carbazones, using a hydroxylamine salt in place of the hydrazine derivative.
Occasionally the oxime must be isolated by ether extraction. The following
procedure is adapted for water-insoluble compounds:
Dissolve 0.5 g. of hydroxylamine hydrochloride in 2-3 cc. of water, add
2 cc. of 10 per cent NaOH solution, 0.2 g. of the unknown, and exactly suf-
ficient alcohol to dissolve the organic compound. The oxime is generally
sparingly soluble and may crystallize from the dilute alcohol as it is formed.
Often it is best to warm the reaction-mixture on the steam-bath for 10 minutes,
using a condenser to avoid loss of solvent. If no sign of reaction is noted after
one hour, the mixture is diluted with 2 volumes of water and the precipitated
product tested to determine whether it is the oxime or the original unknown.
The oximes are usually soluble in dilute alkali and may be reprecipitated by
exact neutralization of the alkahne solution. Why is an excess of acid to be
avoided?
4. Special Condensation Products. — Several of the most com-
mon carbonyl compounds (formaldehyde, acetaldehyde, and
acetone) are derivatized best by means of condensation reactions
other than those discussed above; the two aldehydes may be con-
densed with /3-naphthol according to the directions outlined by
MulKken, I, pages 23-25.
Methylene-di-jS-naphthol, m. 189-92°
Ethylidene-di-/3-naphthyloxide, m. 172-3°
The same derivatives can be applied to compounds like methylal
and acetal, which may be hydrolyzed to yield the above aldehydes.
Acetone may be condensed (Claisen Reaction) with benzalde-
hyde under the influence of alkali to yield dibenzylidene acetone,
/^
CeHsCH^CH— C — CH^CH— CeHs
m.p. 111-112°. Three drops of the ketone are dissolved in 2 cc.
of alcohol and 0.5 cc. benzaldehyde and 1 cc. dilute alkali added
The mixture is heated to boiling for a minute, cooled, and then
agitated in order to cause the supercooled oil to solidify. Crys-
tallization from alcohol yields a pure material.
5. Oxidation Products. — Aromatic aldehydes are very readily
oxidized to the corresponding acids; some of the members (ben-
zaldehyde, for instance) are readily oxidized even by atmos-
pheric oxygen. A general procedure outlined below for the oxi-
dation of the side-chains of aromatic hydrocarbons is generally
applicable to aldehydes also, except that only one-third of the
THE PREPARATION OF DERIVATIVES 155
quantity of permanganate is used. Can this method be recom-
mended for phenoHc aldehydes, such as saUcyl aldehyde, naph-
thol-aldehydes, etc.?
CARBOHYDRATES
No great reliance can be placed upon the melting-points of
sugars and their derivatives; the values vary with the rate of
heating and in the case of the osazones there is too little variation
between melting-points of the individual members. It is for-
tunate, therefore, that an additional, accurately determinable
constant is available, namely, the specific rotation. The value for
this constant should always be determined in connection with the
final identification of a soluble carbohydrate.
Derivatives for Carbohydrates
1. Osazones.
2. Hydrazones.
3. Acetyl derivatives.
4. Mucic acid.
5. Formation of furfural.
1. Osazone formation has been amply illustrated in connec-
tion with the classification reactions (see pages 144 and 84).
Mulliken gives the following approximate figures for the " Time
Test":
Mannose h min. (ppt. is the hydrazone)
d-Fructose 2 min.
d-Glucose 4-5 min.
Z-Xylose 7 min.
Z-Arabinose 10 min. (oily)
d-Galactose 15-19 min.
Saccharose (cane sugar) 30 min.
RafRnose 60 min.
Lactose No ppt. from hot solution
Maltose No ppt. from hot solution
The crystalline form of the osazones should be compared under
the microscope with that of derivatives prepared from known
sugars. Which four of the above sugars yield identical osazones^
and why?
15G
QUALITATIVE ORGANIC ANALYSIS
2. Hydrazones. — For identification by means of melting-points,
the hydrazones are of more value than the osazones, but they
possess the disadvantage that many of them are soluble in water
and therefore isolated with difficulty. The phenylhydrazone of
mannose is very sparingly soluble, the corresponding hydrazones
of arabinose and galactose are soluble in 50-75 parts of water but
not precipitated in such dilutions, whereas those of glucose and
fructose are very soluble. A variety of other aryl hydrazones, such
as p-bromophenylhydrazones, a-methylphenylhydrazones, etc., are
also available for the identification of sugars. Cf. Rosenthaler,
pages 176-234.
Sugar
Melting-point
Phenylhydrazone
Glucose
Arabinose
Galactose
Mannose
Fructose
144-146°
150-153°
158-160°
195-200°
?
3. Acetyl Derivatives. — The acetyl derivatives of sugars may be
prepared by the use of acetic anhydride in the presence of a cata-
lyst, such as anhydrous sodium acetate or zinc chloride. Isomeric
acetyl derivatives may be obtained, the result depending upon the
particular catalyst used. (J. Ind. Eng. Chem. 8, 380, 1916.)
An Illustration of the Preparation of an Acetyl Derivative. — 1 g. of galactose
is gently heated with 15 cc. of acetic anhydride in the presence of 1 g. of
freshly fused sodium acetate. The solution is heated at the boiling-point
for 10 minutes. The acetic anhydride is volatilized by warming on the water-
bath (hood), a little alcohol being added to aid in the removal of the anhydride.
The residue is washed with cold water to remove sodium acetate and the
j3-pentacetyl galactose crystallized from alcohol.
/3-pentacetyl galactose
/3-pentacetyl glucose
Sodium Acetate
m. p. 142°
m. p. 132°
Zinc Chloride
a-form 95°
a-form 111-112'
For further information, the publications of Hudson should be consulted:
J. Am. Chem. Soc. 37, 1267-1285, 1589-93 (1915).
4. Mucic Acid, — Galactose and its derivatives (lactose, galac-
tosides, etc.), yield the insoluble mucic acid upon oxidation with
THE PREPARATION OF DERIVATIVES 157
nitric acid. A portion of the sugar is slowly evaporated on the
water-bath with ten times its weight of nitric acid (sp. gr. 1.15)
until a thick syrup is obtained. This is diluted with a little water
and allowed to crystallize during one hour. Oxalic acid may also
crystallize out but this is readily soluble in warm alcohol. Mucic
acid melts at 213°d.
ACIDS
In connection with the identification of organic acids, the neu-
tral equivalents should always be determined. (See page 138.)
The volatile aliphatic acids (formic to valeric) should be charac-
terized by means of the Duclaux Constants.
Derivatives for Acids
1. Amides, anilides, and toluidides.
2. Solid esters.
3. Elimination of CO2.
4. Anhydrides and miscellaneous derivatives.
1. Amide formation has already been outlined in connection
with the laboratory work, page 138. Low molecular weight acids
yield water-soluble amides, and for this reason it is advisable to
prepare instead the less soluble anilides or p-toluidides (page 144).
MuUiken, I, 80-81, has outlined convenient directions for the iden-
tification of acetic, propionic, butyric, and isobutyric acids in the
form of the corresponding p-toluidides. These acids are usually
met in aqueous solution and it is not feasible to convert them into
acyl halides; instead, the aqueous solution is neutralized with
NaOH, evaporated, and the resultant sodium salt utilized in the
test.
Preparation of p-Toluidides. — In a dry test-tube, mix 1 g. of p-toluidine,
0.4 g. of the powdered sodium salt, and 0.4 cc. of concentrated HCl. Boil
the mixture very gently over a very small gas flame during 15 to 30 minutes.
Cool, extract the reaction product with 5 cc. of boiling 95 per cent alcohol,
pour into 50 cc. of hot water contained in a beaker, and boil down to a volume
of about 10 cc. Filter the hot solution through a small filter paper in a heated
funnel, crystallize the toluidide from the filtrate, dry, and take its melting-
point. Sometimes recrystallization is necessary.
Melting-point
Acet-p-toluidide 146-147°
Propion-75-toluidide 123-124"
Isobutyr-p-toluidide 104-105°
n-Butyr-o-toluidide 72-73°
158 QUALITATIVE ORGANIC ANALYSIS
2. Solid Esters. — A limited number of common acids ^ form
solid esters with methyl alcohol; in such instances, the usual
esterification process, using 0.5 g. of acid, 3 cc. of methyl alcohol,
and I cc. of concentrated H2SO4 may be applied. After reflux-
ing for 15-30 min., the reaction mixture is poured into 10 cc. of
water, the ester filtered off, and recrystallized. Ethyl esters gen-
erally melt lower than the methyl derivatives and with increase in
molecular weight of the alkyls lower melting-points are observed.
(See table on page 151.) With alcohols of fairly high molecular
weight, solid esters are again obtained.
Reid has proposed the p-nitrobenzyl esters
(R-C^O-CH2-C6H4-N02)
and the phenacyl esters
(R-C^O-CHs-C^CgHs)
as convenient derivatives for the identification of hundreds of
organic acids.-
The p-nitrobenzyl esters are prepared by boiling an alcoholic
solution of the sodium salt of the organic acid with p-nitrobenzyl
bromide. For the preparation of phenacyl esters, w-bromoace-
tophenone, is used in place of the nitro-benzyl bromide. In the
more recent papers in the above series is discussed also the separa-
tion and identification of mixtures.
Method. — Dissolve 1 g. of the sodium or potassium salt of the organic
acid (accurately neutralize free acids with alkaU and evaporate) in a boiling-
mixture of 5 cc. water and 10 cc. 95 per cent alcohol. Add 1 g. of p-nitro-
benzyl bromide and boil the solution during 30 minutes. If an insoluble
ester separates from the hot solution, slightly more alcohol may be added.
Finally, the solution is cooled, the crystalline ester filtered off, recrystallized
from dilute alcohol, and the melting-point taken. Valuable details will be
found in the original articles.
3. Elimination of CO2. — Malonic acid and its homologues read-
ily lose CO2 when heated to a temperature of about 140-160°.
This reaction also takes place at a lower temperature when a solu-
tion of the dicarboxylic acid in 20 per cent H2SO4 is refluxed. The
1 m- and p-Nitrobenzoic acids, the dinitrobenzoic, certain halogenated
benzoic acids, terephthahc acid, etc.
-J. Am. Chem. Soc. 39, 124, 304, 701, 1727 (1917); 41, 75 (1919); 42,
1043 (1920); 43, 629 (1921).
THE PREPARATION OF DERIVATIVES 159
resultant monocarboxylic acid may be identified by the methods
given above.
Monocarboxylic acids, particularly in the aromatic series, lose
CO2 when heated with soda-lime; in dealing with carboxy deriva-
tives of solid hydrocarbons, this method may prove applicable.
For example, the naphthoic acids {a and /3) will yield the easily-
sublimable naphthalene. In general, synthetical reactions prove
superior to analytical reactions for the preparation of deriva-
tives. Why?
4. Miscellaneous. — A variety of common acids may be con-
verted into characteristic derivatives by methods not covered
by the above. Details for these less general cases cannot be given
here, but a few examples will be cited.
o-Phthalic acid, when heated to its melting-point and main-
tained at that temperature for a short time, yields the very char-
acteristic, readily-sublimable phthalic anhydride, m.p. 132°.
Cinnamic acid, in common with certain other side-chain unsat-
urated acids, may be characterized as the dibromide addition
product.
Phenolic acids may be identified by reactions involving sub-
stitution in the aromatic nucleus. For example, salicylic acid is
usually converted into the 5-nitro derivative. Mulliken, I,
p. 85.
,CH2R
Acids of the type, QQB.^<f , may be oxidized by the
\CO2H
methods used for side-chain oxidation of aromatic hydrocarbons.
PHENOLS
1. Diphenyl urethanes.
2. Nitration or bromination products.
3. Picrates.
4. Acetyl or benzoyl derivatives.^
The acetyl and benzoyl derivatives of many common phenols
are liquids or low-melting solids and hence they are suitable for
characterization in only a limited number of cases. The diphenyl
urethanes prepared with the aid of diphenyl carbamine chloride
(see example below) are more generally applicable. Mulliken,
I, pages 108-110, outlines directions for nitration of phenol,
' For recent work on the dinitrobenzoates of phenols see J. Am. Phar.
Assn. 11, 608 (1922).
160 QUALITATIVE ORGANIC ANALYSIS
phloroglucinol, resorcinol, and thymol; the bromination of phenol
and pyrocatechin; and the conversion into picrates of a- and /3-
naphthols.
Preparation of Diphenyl Urethanes of Phenols. — Dissolve 1 g. of the phenol
in 5 cc. of pyridine, add 1 g. of diphenyl carbamine chloride and reflux gently
during 30 minutes. The reaction mixture is poured into water. The
derivative is filtered off and crystallized from alcohol.
Melting-points of Diphenyl LTrethanes
Phenol 104-105°
o-Cresol 72-73°
??i-Cresol 100-101°
p-Cresol 93-94°
/i-Naphthol 140-141°
Resorcinol 129-130°
Pyrogallol 211-212°
o-Nitrophenol 113-114°
ESTERS AND ANHYDRIDES
Almost invariably, esters are subjected to hydrolysis and the
resultant acids and alcohols identified as such or otherwise con-
verted into solid derivatives. When the corresponding amide is
characteristic and fairly insoluble, the ester may usually be con-
verted directly into the amide. Quantitative determination of
the saponification equivalents are often of value when identify-
ing esters.
Amide Formation. — 5 cc. or 0.5 g. of ester is added to 10 cc. of concentrated
ammonia water in a half-ounce bottle, and the suspension observed during
several minutes with occasional shaking. If there is no evidence of rapid
reaction, the flask is set aside for several hours or until the following day.
When working with esters, extremely insoluble in water, a few cc. of alcohol
may be added to facilitate reaction. The solid amide is filtered off and crystal-
lized from water or alcohol.
Anhydrides react with ammonia or amines exactly as do the esters except
far more rapidly.
AMINES
A. Primary and secondary amines.
1. Acetyl derivatives.
2. Benzoyl derivatives.
3. Benzenesulfonyl derivatives.
4. Phthalyl derivatives.
5. Picrates,' chloroplatinates, etc.
^For the identification of alkaloid picrates see J. Am. Chem. Soc. 44,
371 (1922).
THE PREPARATION OF DERIVATIVES IGl
B. Tertiary amines.
1. Addition- products with alkyl halides.
2. Substitution products such as nitroso derivatives, (if
aromatic in nature).
3. Picrates, chloroplatinates, etc.
The acetyl derivatives are most often used for the preparation
of derivatives of primary and secondary amines. Often they may
be isolated in connection with the acetyl chloride test for amines
(page 144) but usually it is best to prepare them from acetic anhy-
dride. The reaction mixture is poured into water, warmed to
decompose the excess of anhydride, cooled, and filtered. The
product may be crystallized from water or dilute alcohol.
The benzoyl and benzenesulfony] derivatives may be pre-
pared in aqueous solution as outlined in Exp. 25, page 144.
The formation of easily characterizable double salts with picric
acid, chloroplatinic acid, chloroauric acid, and picrolonic acid is
characteristic of many amines, including the tertiary members;
these derivatives are of special importance in connection with the
identification of quaternary ammonium compounds. The platinum
and gold compounds are convenient for quantitative work. (See
page 170.)
OTHER NITROGEN COMPOUNDS
The nitrogen-containing groups, other than the amino, that are
commonly met are the amide, nitrile, imide, nitro, and azo. As a
general procedure, individuals of the first three types are subjected
to hydrolysis and those of the last two are converted into reduc-
tion products. Definite instructions for these reactions have
already been given in connection with the Classification Reactions,
page 146, and they will therefore not be repeated here.
In many instances these nitrogen compounds possess other
reactive groups and the preparation of a characteristic derivative
need not necessarily involve the nitrogen-containing group. For
example, p-nitrotoluene may be derivatized by reactions involving
(a) the nitro group, (6) the methyl group, and (c) the benzene
nucleus. In this example, all three types of derivatives will be
found to satisfy most of the requirements of good derivatives.
Reduction by the procedure described on page 145 yields the vola-
tile p-aminotoluene, m.p. 43°, which may be identified as such or
converted into the acetyl derivative, m.p. 148°; oxidation of the
162 QUALITATIVE ORGANIC ANALYSIS
methyl group by the alkahne permanganate method described
in the following section yields the characteristic p-nitrobenzoic
acid, m.p. 237°; and nitration according to the methods outlined
presently under toluene, yields 2, 4-dinitrotoluene.
In view of the large number of individual compounds, par-
ticularly of the mixed type, falling in this section, it seems best in
order to conserve the limits of the chapter to consider only a few
typical individual examples.
Note and discuss derivatives and methods of preparation
selected by Mulliken, Vol. II, for the compounds listed below.
135 Salicyl amide.
168 Phthalamidic acid.
304 Hippuric acid.
1468 Methyl-o-aminobenzoate.
1462 Nitroglycerine.
1568 Diphenylamine.
1733 2, 4, 6-Trinitrotoluene.
1787 Anesthesine.
1946 Antipyrine.
2555 Phthalimide.
2619 Betaine.
2636 Succin-a-naphthalide.
2642 /-Tyrosine.
2561 Caffeine.
2651 Theobromine.
2750 Phenyl isocj-anate.
2781 Benzonitrile.
2796 Nitrobenzene.
2804 o-Nitrotoluene.
2882 Azoxybenzene.
2945 o-Nitroaniline.
2989 ??-Nitrosodiethylaniline.
2996 p-Nitrosodimethjdaniline.
3016 m-Dinitrobenzene.
3027 Benzoyl-o-nitroanilide.
3126 2, 4-Dinitrophenol.
3168 Picric acid.
3191 p-Nitrosophenol.
36 8-IIydroxyquinoline.
72 2?-Nitrophenol.
75 p-Nitrobenzylcyanide.
THE PREPARATION OF DERIVATIVES
163
139
164
425
148
259
290 J
Nitrobenzoic acids.
Aminobenzoic acids.
HYDROCARBONS AND THEIR HALOGEN DERIVATIVES
The saturated aliphatic hydrocarbons comprise the class of
organic compounds most resistant toward the usual chemical
reactions; the preparation of characteristic derivatives is there-
fore a difficult matter. Moreover, this class of compounds is not
ordinarily met in the form of individuals but rather in the form of
complex mixtures, as, for example, in the various fractions from
petroleum. Final tests applied in the identification of paraffin
hydrocarbons, therefore, consist in the application of a variety of
physical tests, such as boiling-point range, specific gravity, refrac-
tive index, etc. Preliminary work, of course, must conclusively
demonstrate the absence of appreciable amounts of compounds
other than paraffin hydrocarbons.
In connection with the identification of unsaturated hydro-
carbons, valuable data are furnished by titration with bromine;
the bromine addition products may often be used for melting-point
or boiling-point determinations. Among the terpenes, the addi-
tion products formed with bromine, halogen acid (usually HCl),
and nitrosylchloride are of considerable value. The latter deriv-
atives react with organic amines to yield nitrosylamines. (Cf.
Rosenthaler, pages 22-28.)
d- and Z-Limo
nene
Dipentene . . . .
Pinene
Camphene. . . ,
Boiling-point
of Terpene
175-6°
177-8°
155-6°
160°
Solid Derivatives of Mono- and Dicyclic
Terpenes
Melting-point
of Hydro-
chloride
50°
131°
150-160°
Melting-point
of Bromide
104°
169-170"
Melting-point
of Nitroso-
benzylamine
93°
109°
122-3°
164 QUALITATIVE ORGANIC ANALYSIS
The halogen derivatives of aHphatic hydrocarbons may usually
be conclusively identified by a combination of physical constants
accompanied by a quantitative estimation, as outlined in Chapter
XI, page 168. A variety of reactions for the preparation of solid
derivatives are here available.
1. Quaternary ammonium compounds.
2. Solid esters.
3. Substituted phthalimides.
4. Reduction products.
1. Quaternary Ammonium Compounds are prepared by mixing
one part of the halogen compound with approximately the theo-
retical proportion of a tertiary amine, such as dimethylaniline,
pyridine, quinoline, trimethylamine, etc. The particular ter-
tiary amine chosen should be one yielding a derivative with a con-
venient melting-point. Occasionally the platinic chloride deriva-
tive of the quaternary compound will be found to posses a definite
melting-point.
2. Solid esters may be prepared by a method exactly analogous
with that given (page 158) for the identification of acids, except
that now a salt of a known acid is chosen. The reaction will be
found to be less smooth than that involving the use of p-nitro-
benzyl bromide or phenacyl bromide, since certain halogen com-
pounds may undergo loss of halogen acid with the resultant pro-
duction of unsaturated compounds; the reaction velocity is also
lower.
3. Substituted phthalimides are prepared by heating ^ g. of
potassium phthalimide with ^ cc. of a monohalogen compound
usually in a sealed tube (150°-200°). The resultant derivatives
are insoluble in dihde alkali, and thus can be separated readily
from unchanged phthalimide.
In the following table are listed a few substituted phthalimides.
(Beilstein, II, 1799-1805; II,* 1051-1053.)
Substance
Melting-point
/CO.
C6H4< >N-CH3
^CQ/ -CH2CH3
132°
78-9°
-CH2CH2CH3
66°
. -CH(CH3)2
85°
Supplement of Vol. II.
THE PREPARATION OF DERIVATIVES 165
Substance Melting-point
.CO.
CsHZ \N-CH2CH2CH2CH3 65°
^CQ/ -CH2CH(CH3)2 93°
-CH2-CH = CH2 70-71°
-CH2-C0H5 115-6°
-CH2C6H4CH3 ortho 148-9°
-CH2C6H4CH3 meta 117-8°
AROMATIC HYDROCARBONS AND THEIR HALOGEN
DERIVATIVES
The two main reactions used in connection with the identifica-
tion of aromatic compounds are (a) nitration and (b) oxidation of
side-chains. Hydrocarbons of the condensed type yield definitely
melting picrates.
Nitration.^ — (a) Add I cc. of the unknown to a mixture of 1 cc. concen-
trated HNO3 and 1 cc. concentrated H2SO4. Agitate the mixture and note
any evolution of heat. Finally, warm gently over a small flame and agitate
the mixture for at least one minute. After cooling somewhat, pour the reac-
tion mixture upon a small amount of cracked ice. Separate the nitro com-
pound and separate from any oily material by crystallization from alcohol.
Comments: This procedure will yield m-dinitrobenzene from either
benzene or nitrobenzene, the p-nitro derivatives from chlorobenzene, bromo-
benzene, benzyl chloride, etc. Toluene yields an oily mixture of o- and
p-nitro compounds and should be subjected to procedure (b).
(b) Add about 3 or 4 drops of the hydrocarbon to 1 cc. of fuming nitric
acid. Add 1 cc. of 5 per cent fuming sulfuric acid and warm gently over
the free flame during about one minute. Isolate and purify the product
as under example (a).
Comments: Toluene, o-nitrotoluene, and p-nitrotoluene will yield 2, 4-
dinitrotoluene in this reaction; mesitylene, m-xylene, p-xylene, and pseudo-
cumene yield trinitro derivatives.
Oxidation of Side-chains. — This reaction is applicable to a
great variety of aromatic compounds; it is not feasible when the
aromatic nucleus contains a phenolic or amino group either of
which, when unprotected will lead to the destruction of the ring
structure.
1 Precaution. — Even when working with small quantities of material,
special precaution must be observed in every nitric acid test, since certain
organic substances may react violently. Losses of eyesight may easily result.
166 QUALITATIVE ORGANIC ANALYSIS
Procedure. — Into a 150 cc. r.b. flask, ^ place 75 cc. of water containing
3 g. of KMn04. Add 1 cc. of the unknown and boil gently under the reflux
condenser (why?) for about | to 2 hours, i.e., until the purple color of the
permanganate has been replaced entirely by the brown of precipitated man-
ganese dioxide. Filter the mixture and evaporate the filtrate to about one-
half volume on the water-bath. Acidify to precipitate the organic acid,
recrystallize from water or dilute alcohol, dry, and take melting-point.
Comments: The yield is poor with such hydrocarbons as toluene, ethyl
benzene, butyl benzene, etc., but is very satisfactory with the disubstituted
products such as the nitrotoluene, the chloro- and bromo-toluenes, the xylenes,
etc. When the side-chain consists of a — CH2OH or — CHO group, the
yield will of course be better still and this is true also for the — CH2CI and
— CHiBr side-chains. When reactive halogen is known to be present, about
i g. NaoCOs should be added to the reaction-mixture.
Compounds with somewhat more complex side-chains may behave some-
what abnormally, for example, acetophenone yields C6H5COCO2H and naph-
thalene yields some C6Hi-C02H-COC02H. In such special cases, the MnOa
is not filtered from the reaction mixture but the latter is acidified directly.
In acid solution, MnOo will oxidize quickly the above oxalyl derivatives to
benzoic and phthalic acid, respectively. Any excess Mn02 is then removed
by the addition of a little sodium bisulfite.
Preparation of Picrates. — Dissolve 0.1 g. of hydrocarbon (naphthalene,
phenanthrene, or acenaphthene) and 0.2 g. of picric acid in 5 cc. of boiling
95 per cent alcohol. Allow the solution to cool gradually. Filter off the
yellow crystals, RH-C6H2(N02)30H, and recrystallize from a small amount
of alcohol. Dry on a clay plate and take melting-points.
Substance Melting-point
Picric acid 121°
Naphthalene picrate 150°
Phenanthrene picrate 143°
Acenapthene picrate 161°
1 A round-bottom flask is required since bumping may break an ordinary
flask. A copper utensil avoids the difficult}' of "bumping."
CHAPTER XI
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS
It will seldom be necessary in this course to resort to methods
of ultimate analysis, and it is for this reason that combustion
methods for carbon, hydrogen, and nitrogen are omitted from this
chapter. This is true also of the Carius determination for halogens
and the fusion methods for sulfur, arsenic, and phosphorus.
In dealing with compounds of unusual difficulty, the methods of
ultimate analysis may have to be employed, but under such cir-
cumstances the student is directed to other sources ^ where direc-
tions will be found in more detail than would be justifiable here.
Several of the qualitative methods and particularly the esti-
mation of certain reactive groups, however, are of considerable
value in connection with identification work, not merely in the
first stages of an analysis but also in connection with confirmatory
tests when the preparation of derivatives is not feasible. More-
over, a considerable number of such tests involve simple volumetric
methods and require comparatively little time when the standard-
ized solutions are available. Some of the more adaptable methods
are, therefore, given here but the student is encouraged to become
familiar with more advanced treatments of the subject ^ that will
supply a greater variety of methods together with valuable refer-
ences to the original articles.
Determination of Nitrogen by the Kjeldahl Method. — Most
organic compounds in which nitrogen is present in non-oxidized
form are decomposed when digested with sulfuric acid with the
resultant formation of ammonium sulfate. The ammonia may
^ Weyl, Meyer, Lassar-Cohn, etc. Some of the more elementary labor-
atory manuals give excellent treatments of the subject. This is true especially
of Gattermann's Practical Organic Chemistry, Noyes' Organic Chemistry for
the Laboratory, and Fisher's Laboratory Manual of Organic Chemistry.
^ For references, see the end of this chapter.
167
1G8 QUALITATIVE ORGANIC ANALYSIS
then be liberated with a non-volatile alkali, distilled from the mix-
ture into a known volume of standard acid, and determined volu-
metrically by titrating the excess acid,
A known weight (usually 0.300 g.) of the substance is placed in a 500 cc.
Kjeldahl flask and dissolved in 25 cc. of pure concentrated sulfuric acid. Five
grams of potassium sulfate and 0.25 g. of copper sulfate are added and the
mixture gradually heated to boiling over a small flame and subsequently
digested at the boiling temperature during one or two hours or until the liquid
is practically colorless.
The oxidized mixture is allowed to cool, diluted carefully with 250 cc.
of distilled w^ater and a few chips of porous plate added. A 40 g. portion of
solid stick NaOH c.p. is then carefully added to the cool solution and the
flask immediately connected with the condensing apparatus, the receiving
flask of which must be in place. After the caustic has dissolved, the solution
is slowly distilled until at least 100 cc. of distillate has been collected. This
should require about one-half hour.
The receiving flask consists of a 250-cc. Erlenmeyer flask containing 30 cc.
of standard 0.2 N. sulfuric acid and a few drops of congo red (or methyl
orange) indicator. The tip of the exit tube should be immersed in the
standard acid. After the distillation is complete, the excess acid is titrated
with 0.2 N alkaU.
Since some of the materials used in the analysis will contain traces of nitro-
genous matter, it is necessary to run a blank determination and apply the
correction to the values obtained with the unknown.
The results are calculated either as percentage of nitrogen or according
to the formula:
^ . , „, . , Wt. of Sample X 1000
Equivalent Weight ^ = - — — — — .
Cc. Normal acid used
DETERMINATION OF HALOGENS ^
Most organic halogen compounds including many of the more
stable aromatic types are readily decomposed by metallic sodium
in absolute alcohol. The halogen is then precipitated by the addi-
tion of standard AgNOs solution and the excess of the latter
determined by titration according to the Volhard method.
A known weight of the organic compound (about 0.250 g.') is placed in
^ This value will be equal to the formula weight if the molecule contains
one nitrogen atom; when two or three nitrogens are present, the apparent
molar weight wiU be one-half or one-third, respectively, of the actual molar
weight.
2 Stepanow, Ber. 39, 4056 (1906). Noycs Lab. Manual, 1916, p. 23.
* If the substance is a liquid, the portion used in the specific gravity
determination is utilized and therefore no additional weighing of sample is
required.
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 169
a 100-cc. long-neck r.b. flask together with 35 cc. of absolute alcohol. The
solution is heated to boiling under a condenser and 3.5 g. of metallic sodium
added gradually to the boiling solution during about twenty minutes. Finally,
the solution is heated for one-half hour longer, when the sodium should be
dissolved.
Cool the solution and add cautiously, through the condenser, 50 cc. of
distilled water. Transfer the solution to a 250 cc. Erlenmeyer flask, acidify
with nitric acid (chlorine-free), filter if necessary, and precipitate the silver
halide by the addition of a slight excess of N/10 AgNOs. Add ferric alum
as an indicator and titrate the excess AgNOa by means of N/20 thiocyanate
solution. (If the halide is chlorine, the ppt. of AgCl should be filtered off
before titrating with thiocyanate. Why?)
In the calculation of results, use a formula analogous with that given
above under the nitrogen determination.
lonizable Halogen. — Substances yielding ionizable halogen
when dissolved in water can usually be estimated directly without
the digestion with sodium. The most common substances met in
this class are the hydrochlorides of organic bases.
ANALYSIS OF METALLIC DERIVATIVES
Na, K, Ca, and Ba Salts. — About a 0.250 g. portion of the
sample is weighed out in a tared platinum ^ or porcelain crucible
and heated in a drying oven at 120° for several hours, until con-
stant weight is attained. The loss in weight usually represents
water of crystallization. Occasionally, substances are met that
require drying at appreciably higher temperatures.
The crucible is now heated over a small free flame' until all
initial decomposition is complete. After cooHng, the residue is
treated with two drops of concentrated sulfuric acid, heated very
gently with indirect flame until fumes of SO3 cease to escape,
and finally heated to dull redness until the residual sulfate is prac-
tically white. (With sodium and potassium sulfates, the heating
must be sufficiently low to prevent volatility.) The residual sul-
fate, that may be contaminated with a trace of sulfide, is best
treated with one more drop of H2SO4, and heated to constant
weight.
Ammonium Salts. — Ammonium salts may be estimated by the
Kjeldahl procedure without requiring sulfuric acid digestion.
^ Platinum is not used in the presence of phosphorus, arsenic, lead, etc.
Why?
170 QUALITATIVE ORGANIC ANALYSIS
Silver and Platinum Salts. — In connection with identification
work, silver salts of organic acids and platinic chloride double salts
of organic bases are prepared, particularly when only small amounts
of material are available for investigation. The silver salts are pre-
pared by exactly neutralizing the organic acid with NaOH, adding
the requisite amount of silver nitrate, filtering, washing thoroughly
with water, and drying at 100°. The platinic chlorides are pre-
pared by dissolving the organic base in hydrochloric acid,
adding about ^ mole of chloroplatinic acid, filtering off the salt,
(R-NH3)2PtCl6, and crystallizing from alcohol when feasible.
A 0.200 g. portion of the dry salt is then gently ignited in a
porcelain crucible and weighed either as metallic Ag or as metal-
lic Pt.
In addition to being of constant composition, the platinic
chlorides of some organic bases possess definite melting-points and
characteristic crystalline structures. The latter property, espe-
cially, suggests their importance in micro-analysis.
ESTIMATION OF UNSATURATION
A number of the simple ethylene derivatives may be titrated
quantitatively with bromine. The test is, of course, applied only
when the previous classification reaction has shown that bromine
is decolorized without appreciable substitution taking place. The
weighed substance (about 1 g.) is dissolved in 25 cc. of carbon
tetrachloride, the mixture cooled in a freezing bath, and titrated
with a bromine solution of known strength (about N/2) until a
faint bromine color remains.
The following modified method, that of Hanus, is of general
application and serves also in technical analysis for the deter-
mination of the iodine numbers of natural products such as fats,
fatty acids, waxes, etc.
The iodine solution is prepared by dissolving 13 g. of iodine in 1000 cc.
of glacial acetic acid and adding 3 cc. of bromine to the cold acetic acid solu-
tion.
A 0.200 g. sample is transferred to a 250 cc. glass-stoppered Erlenmeyer
flask and dissolved in 10 cc. of chloroform. To this solution there is now
added 25 to 50 cc. of the iodine solution (about 50 per cent excess should be
used), and the mixture allowed to stand, with occasional shaking, for thirty
minutes.
The reaction mixture is next treated with 2 g. of KI dissolved in about
10 cc. of water, shaken thoroughly, and 100 cc. of distilled water added. The
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 171
excess of iodine is titrated with standardized N/10 sodium thiosulfate solu-
tion until only a faint iodine color remains. The solution is now again shaken.
One cc. of starch paste is added, and the titration continued until the blue
color just disappears.
While the above determination is being carried out, a blank determi-
nation is conducted in exactly the same manner. This is essential because
changes in the acetic acid-iodine solution make it inadvisable to assign a
definite normality factor to this solution.
The iodine number of a substance represents the percentage of iodine
(or its equivalent) absorbed by the sample. Thus when a sample weighing
0.200 g. absorbs an equal weight of iodine, it possesses an iodine number
of 100.
ESTIMATION OF HYDROXYL
The hydroxyl group is estimated best by indirect methods.
The hydroxyl compound is converted into an acetyl, benzoyl,
or analogous derivative and the resultant ester subjected to
saponification according to the method described below for esters.
The molar equivalent of the hydroxy compound is thus equal to
the saponification equivalent of the ester minus the molecular
weight of the acyl radical with a +1 correction for the hydrogen
atom. In this determination, it is, of course, also essential to
subject the original compound to saponification test. For example,
the compound CHOH-CO2C2H5 will yield the corresponding
I
CHOH-CO2C2H5
diacetyl derivative but upon saponification of the latter, four
molecules of alkali will be involved.
The reaction products of certain alcohols with phthalic anhj'-
.CO2R
dride, C6H4<^ , may be isolated and used for the determi-
\CO2H
nation of neutral equivalents. The molar weight of the radical
R may thus be determined.
ESTIMATION OF THE CARBONYL GROUP
This determination is seldom required and consequently no
detailed directions are given. The references at the end of this
chapter should be consulted. The main methods are as follows :
1. By choosing a hydrazine derivative of sufficiently high
molecular weight, like /3-naphthylhydrazine, extremely insoluble.
172 QUALITATIVE ORGANIC ANALYSIS
solid hydrazoncs are obtained and these may be weighed directly
after dryiiig in the oven.
2. The carbonyl compound in alcohol is treated with a slight
excess of hydroxylamine sulfate solution. A known amount, but
no excess, of standardized alkali is now added. After completion
of the reaction, the remaining hydroxylamine is,, titrated with
standard acid using methyl orange.
3. The aldehyde or ketone may be converted into the phenyl-
hydrazone and the excess of reagent determined by measuring
the volume of nitrogen gas liberated by Fehling's solution at the
boiling temperature. The hydrazone is not attacked by this
oxidizing agent.
C6H5NHNH2+O -^ C0H0+N2+H2O
4. Important quantitative methods in the sugar group are
based upon the behavior of reducing sugars with Fehling's solution.
The amount of reduction that has taken place, under certain
specified experimental conditions, may be determined from the
amount of CuoO formed, which may be estimated either gravi-
metrically or volumetrically. In connection with identification
of individual sugars, this method is however of little value.
ESTIMATION OF THE CARBOXYL AND ESTER GROUPS
The carboxyl group may be determined by direct titration
according to the method suggested in the classification reactions
in Chapter IX, Exp. 14. The saponification of esters, likewise,
is illustrated in laboratory experiment No. 17.
ESTIMATION OF ALKOXYL GROUPS
The Zeisel method ^ is based upon the fact that alkoxyl groups,
whether in ethers or esters, are decomposed by heating with strong
hydriodic acid to yield alkyl iodides. The latter are absorbed
in alcoholic AgNOa and estimated as Agl.
/OCH3 /OH
CgH4< +HI -> CcH4< +CH3I
\CO2H \CO2H
1 Internal. Cong. Applied Chcm. Ill, Vol. 2, p. 63 (1898). J. Chem. See.
81, 318; 115, 193 (1919).
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 173
When the Zeisel method is appHed to compounds containing
nitrogen, it must be remembered that alkyl groups on nitrogen may
occasionally be partially replaced to yield alkyl iodides. On the
other hand, under the influence of HI, an alkyl grOup might con-
ceivably be transferred from oxygen to nitrogen.
The apparatus ordinarily used in that shown in Fig. 12.
Fig. 12.
For the analysis of a 0.300 g. sartiple, the 50 cc. r.b. flask A is charged
with 15 cc. of redistilled aqueous hydriodic acid (sp. g. 1.68), a chip of clay-
plate and a trace of red phosphorus. It is connected with the small con-
denser B containing water at about 40-60° which, in turn, is connected with
three wash bottles C, D, and E. The first contains warm water and ^ g. of
red phosphorus to remove HI and I2 vapors, while D and E contain 40 cc.
and 20 cc. respectively of a saturated solution of AgNOa in absolute alcohol.
Before proceeding with an analysis, a blank test is made. The flask A
is heated to cause appreciable refluxing. A stream of CO2, purified by passing
through aqueous AgNOa and next through HoSOj, is passed through the
apparatus (but not through the HI solution) as indicated. No turbidity
should be observed in the flask D during an interval of about 10 minutes.
The flask A is now cooled, the sample introduced, and the heating and
passing of CO2 repeated. A white precipitate of the silver iodide-silver
nitrate double salt separates in flask D after about 10 minutes and the reac-
tion is usually completed in 40 minutes.
The silver nitrate solutions are now combined, diluted with several volumes
of water, acidified with nitric acid, boiled gently for several minutes, and the
silver iodide determined gravimetrically.
174 QUALITATIVE ORGANIC ANALYSIS
The above procedure is satisfactory with non-volatile unknowns.
In dealing with appreciable volatile products, special precautions
must be taken in adding the weighed sample and the water in the
condenser B must be kept cold during the early stage of the heating.
ESTIMATION OF THE AMINE GROUP
1. The derivatives formed by the reaction of primary and
secondary amines with phthalic anhydride,
C6H4<; and C6H4< ^R
\CO2H \CO2H
may be isolated, purified by cr3^stallization from water or dilute
alcohol, dried, and titrated against standard NaOH as in the deter-
mination of neutral equivalents of other organic acids. By sub-
tracting 148 from the neutral equivalent value, the equivalent
weight of the amine is obtained. A modification of this method is
outlined below.
2. Many free aliphatic amines may be titrated directly with
standard acid in the presence of methyl orange or congo red.
Salts of weak bases (aryl amines) with strong inorganic acids
(HCl, H2SO4, HNO3) may be titrated directly with standard
alkali using phenolphthalein as an indicator.
The above phthalic anhydride method for the estimation of
the primary and secondary amine groups may be modified as
follows :
0.200 g. of pure phthalic anhydride ^ is placed in a dry 100 cc. glass-
stoppered cylinder and dissolved in about 5 cc. of benzene. To this solution
there is now added 0.100 g. of the amine under examination dissolved in 10 cc.
of benzene or alcohol-free ether. The mixture is thoroughly shaken during
several minutes. 27.0 cc. of N/10 NaOH is added and the solution again
shaken for several minutes in order to insure decomposition of any excess of
phthalic anhydride. A few drops of phenolphthalein are now added and the
solution titrated to the neutral point with N/10 acid. Since 27 cc. of N/10
alkali represents the exact amount required for neutralization of the phthalic
anhydride, the amount of N/10 acid consumed serves for the calculation of
the equivalent weight of the amine.
Wt. of sample X 1000
Equivalent Weight
Cc. N/1 acid used
1 With amines of low m. wt. (below 74), the amoimt of phthalic anhydride
must be increased and a proportional volume of alkali used.
QUANTITATIVE ANALYSIS OF SUBSTITUENT GROUPS 175
The above test possesses distinct advantages over the older
acetic anhydride method. Phthahc anhydride is obtainable in
practically 100 per cent purity and blank determinations are
usually not required. Moreover, since the reagent is a solid, it
may be weighed more conveniently. The method may experience
a limitation in a few special instances where insoluble salts are
formed between the organic acid and the amine; in such instances
the alkali must be added slowly and in small portions so as to lib-
erate the amine and permit complete reaction with the anhydride.
REFERENCES
Meyer: Analyse und Konstitutionermittelung organischer Ver-
bindungen.
Weyl: Methoden der organischen Chemie.
Allen: Commercial Analysis.
Sherman: Organic Analysis.
Lassar-Cohn : Arbeits-Methoden.
Meyer-Tingle: Determination of Radicals in Carbon Compounds.
Vaubel: Methoden der quantitativen Bestimmung organischer
Verbindungen.
Kingscott and Knight: Methods of Quantitative Organic Analysis.
CHAPTER XII
EXAMINATION OF MIXTURES
The ideal method to be followed in the identification of the
components of a mixture consists in, first, separating the unknown
into its pure individuals and, second, identifying each individual
according to the method already outlined (Chapter VI). Only in
exceptional instances will it be permissible to attempt an identi-
fication of the constituent of a mixture without a previous sepa-
ration.
The laboratory work in this part of the course will include a
study of two or three relatively simple mixtures, each consisting
of from two to six components. The identification of these mix-
tures will require a thorough mastery of the preceding work, espe-
cially since it is impossible to outline a set of procedures that may
be applied directly to the great variety of combinations that may
be met. More or less specific instructions may be given, however,
concerning the preliminary examination of mixtures.
A thorough prelinmiary examination should always precede any
attempt made to separate a mixture. — To the experienced analyst,
certain " short-cuts " will always be apparent, but for the beginner
and usually for the experienced chemist also, a thorough prelim-
inary examination is by far the best *' short-cut " to be found.
In the case of a liquid unknown, there is always the temptation to
proceed immediately to a fractional distillation and in the case of a
solid mixture we find too often that the first attempt at analysis
has been a resort to the use of the wrong solvents. It is only after
the preliminary examination that one can decide upon the most
logical and satisfactory method for the final separation. Although
these preliminary tests are usually similar for diff"erent mixtures,
the final methods of separation will be difi'erent in every case,
since it will then be possible to dispense with all unnecessary steps.
176
EXAMINATION OF MIXTURES 177
In outlining methods for the preHminary examination, we shall
limit ourselves to two types of mixtures: (a) water-insoluble and
(b) water-soluble. Naturally, many mixtures will fall in an inter-
mediate field, some of the ingredients being water-soluble and others
insoluble in water. Alcoholic solutions of water-insoluble com-
pounds furnish a very common example of this type. Frequently
the solubility in water of certain ingredients will be appreciably
affected by the presence of other compounds, particularly by sol-
vents. It is felt, however, that a study of the common methods of
attack of the two extremes will enable the student to deal effect-
ively with intermediate types also. Occasionally, it may be
necessary to conduct preliminary examinations on both the water-
soluble and the water-insoluble parts of a mixture; such examina-
tions are not conducted independently but the results found in
the examination of one fraction are used to facilitate the study of
the other.
The greatest possibility of error in connection with the sepa-
ration of mixtures lies in missing an ingredient which, although of
importance, may be present only in traces and may require some
special test. In actual technical work, such difficulties are only
apparent since additional information concerning the source of
the material and the use for which it is intended is usually avail-
able.
In connection with a study of mixtures, it is essential to keep
in mind continually the possibility of interaction between the
ingredients and especially the possibility of decomposition during
the process of separation; for example, easily hydrolyzable esters,
amides, and anhydrides may be met in the form of their decompo-
sition products. Cases of doubt call for a study of the original
sample.
OUTLINE FOR THE PRELIMINARY EXAMINATION OF A
MIXTURE
(Record notes in the order outlined here)
Mixtures of Type A. (Insoluble in Water.)
I. Physical Characteristics. — Examine the unknown for color,
odor, homogeneity, etc. In the case of a solid, it will often be
possible to observe various forms of crystals (and especially so
when a microscope is used) and often small fragments of the pure
178 QUALITATIVE ORGANIC ANALYSIS
individuals may be isolated mechanically. If this is possible, it is,
however, no excuse for a variation in the following steps, since a
more effective method of separation will usually be found. In the
case of certain mixtures, as when a solid is in suspension in a liquid,
or when dealing with two liquid layers, it is best to separate the
mixture into two parts, filtering in the first instance and using the
separatory funnel in the second. Tests should then be made upon
each portion of the mixture. In such cases, it is to be expected
that certain ingredients will be found in both parts of the mix-
ture.
II. Ignition Test. — Ignite a small amount of material on plat-
inum foil or in a crucible and apply the usual observations, viz.,
fusion temperature, appearance of the flame, odor, presence of
inorganic material, etc.
III. Elementary Analysis. — Although analyses will be made on
the fractions to be separated later, it is necessary to run also an
elementary analysis on the original mixture; the result obtained
may serve to detect an ingredient which might otherwise be over-
looked.
IV. Solubility Behavior. — The solubility tests differ from those
applied to individual compounds in one essential point; it is neces-
sary to determine whether any part of the mixture has dissolved.
This is done by separating the solvent and examining it for dis-
solved material by precipitation, extraction, or distillation meth-
ods, or by combinations of such methods. Diminution of volume
in liquid unknowns is occasionally of value. The following scheme
is of value in connection with the application of solubility tests
on a water-insoluble mixture. A one-gram sample will usually
serve for these tests and the suction pipette, page 112, will be
found of particular value in connection with the separations and
extractions. All fractions are to be retained for later use.
Fraction C will contain the water-insoluble basic compounds
as well as amphoteric compounds; alkalinization will precipitate
the former but not the latter. From fraction D the insoluble
acids may be removed by acidification. How will you test for the
amphoteric group?
In order to secure reasonably sharp separations, it is well to
apply two acid and alkaline extractions respectively. It is well
also to wash fractions C and D with small portions of ether (Why?),
although these ether washings may be discarded. Before precip-
EXAMINATION OF MIXTURES
179
itating the organic bases and acids from fractions C and D, it is
advisable to remove dissolved ether (Why?) by gentle warming.
UNKNOWN.
If Liquid, Remove any Volatile Solvent by
Distillation on Water-bath
Volatile
Solvent
Residue. Treat with Ether
A
Insoluble
Part
B
Soluble in Ether. Treat with dilute HCl.
Soluble Part
C
Ether Layer. Wash with a small
volume of HoO. Treat with
dilute KOH.
Soluble Part
D
Ether Layer. Dry
with a little Na2S04
and evaporate to
obtain indifferent
compounds.
E
V. Subsequent Fractionation. — The various fractions obtained
in connection with the solubility tests will not necessarily consist of
individual compounds; each fraction may require further separa-
tion, for example, D may consist of a mixture of acidic compounds
and E of a mixture of neutral substances. Tests for homogeneity
must therefore be applied to the individual fractions and, if neces-
sary, a given fraction must be subjected to further separation.
This is done usually in connection with the final separation of the
main mixture. Suggested procedures will be discussed subse-
quently and are also illustrated in the problems at the end of this
chapter.
VI. Outline of Plan. — Using the data obtained above, record
in your notebook a list of possible homologous series present in the
mixture and outline in your notebook a diagrammatic scheme for
the separation of the mixture, submitting this to your instructor
for his approval.
VII. Proceed with the FinpJ Separation of the Mixture. — Use
a weighed quantity of material and weigh the separate fractions
obtained.
180 QUALITATIVE ORGANIC ANALYSIS
VIII. Identify the individuals isolated from the mixture by the
steps previously outlined (Chapter VI) for the Identification of
Individual Compounds.
Mixtures of Type B (Water-soluble)
I. Preliminary examination as described under Procedure A.
II. Ignition Test. — Ignite a small amount of the material on
platinum foil. If the substance does not burn readily, it may be
an aqueous solution and whether or not this is the case will be
indicated by the fact that the mixture is soluble in water but insol-
uble in ether and possesses a low boiling-point.
III. Elementary Analysis. — Precaution! Do not apply the
sodium decomposition test to aqueous solutions! In such cases,
reserve the elementary analysis until the individual fractions are
being examined. The aqueous solution should be examined, how-
ever, for inorganic radicals.
IV. Solubility Behavior. — Apply the following tests to the
aqueous solution:
(a) Test aqueous solution with litmus and phenolphthalein.
(b) Extract a small portion with ether, dry the latter with
anhydrous Na^SO^ and evaporate on a watch glass, avoiding con-
densation of moisture.
(c) To a small portion, add HCl (unless the original is strongly
acidic) and cool. Note evolution of gas, formation of precipitate,
etc. Apply an ether extraction test to the acidified solution.
(d) To a small portion, add KOH and cool. Observe color
changes, evolution of gases, formation of precipitates, etc. Apply
an ether extraction test to the alkaline solution.
(e) Evaporate a cubic centimeter of the original aqueous solu-
tion to dryness on the water-bath. Is a residue left?
V. Distillation and Miscellaneous Tests.— Aqueous solutions
should be subjected to the following distillation tests. This
method of separation is particularly valuable in the examination
of quite dilute (1 to 5 per cent) aqueous solutions. Any individ-
ual volatile fraction may be fiu'ther concentrated bj^ redistillation.
(o) To a portion of the original mixture, add NaOH and distill
carefully.
EXAMINATION OF MIXTURES
181
Non- volatile part. Add dilute H2SO4. Distill.
Volatile Part
If sulfuric acid causes
acid.
charring, use phosphoric
Aqueous solution of:
Volatile Part
Non-volatile part
Volatile Bases
Volatile acids
Volatile indifferents
If distillate is neutral
Contains K2SO4 with
Alcohols
or requires only a
non-volatile part.This
Aldehydes
little N/10 alkali for
non-vol. part may be
Ketones
neut. then volatile
different from that
If the sp. gr. of this dis-
acids are absent.
obtained by evapor-
tillate is that of pure
ation of the original
water then this group
solution. Why?
is absent. How would
the basic group be
separated here from
the indifferent?
From the aqueous solution containing only the volatile indifferents, the
latter may be salted out very effectively with K2CO3 unless the solution is too
dilute.
(6) Apply the phenylhydrazine test, the iodoform test, the
FeCls test, the Br2 water test, etc., to small diluted portions of the
original solution, or, better still, to the volatile part of the mix-
ture. Be sure that these tests are applied under proper condi-
tions, especially when applied to the original mixture. To illus-
trate: Sulfates or oxalates might yield precipitates with phenyl-
hydrazine, sulfites would decolorize Br2 water, etc.
VI, VII, and VIII. (Proceed as Outhned for Mixtures of Type A.)
After a mixture has been separated into certain groups (acidic
group, indifferent group, etc.), it is necessary to determine by the
application of the usual tests for purity whether these fractions
consist of one or several individual compounds.
When more than one individual is found in a given solubility
group, additional operations are involved; subsequent separations
are affected preferably by physical methods but, as a last resort,
chemical methods which yield certain products in the form of
derivatives may be required.
182 QUALITATIVE ORGANIC ANALYSIS
Physical methods of separating a given solubiHty fraction con-
sist in the application of fractional distillation, fractional crystalli-
zation, crystallization from solvents of various types, steam dis-
tillation, sublimation, etc. Such operations are already familiar
to the student but nevertheless abundant opportunity remains
for the exercise of his .'ingenuity when relatively small amounts of
material are available.
Separation of the Acidic Fraction
Among the acidic substances, separations may be affected occa-
sionally by taking advantage of the variations in acidity. When
excess carbon dioxide is passed into the solution of the acidic frac-
tion in alkali, weak acids (when sparingly soluble in water), as,
for example, certain amides, imides, phenols, etc., will be precip-
itated while the stronger acids remain in solution.
The principle of fractional precipitation is often of value when
mere crystallization fails. The fraction is dissolved in alkali
(dilute solution) and precipitated in fractions by the cautious addi-
tion of dilute hydrochloric acid. In working with sparingly soluble
acids, the solutions must be dilute and the acid added with vig-
orous stirring in order to prevent the contamination of the product
with salts of the organic acids.
The use of insoluble salts (calcium, lead, etc.) may occasionally
be used to advantage in the separation of mixtures of carboxylic
acids.
Among the volatile fatty acids, the Duclaux method is applica-
ble not merely to identify the individual compounds but also to
examine mixtures. An aqueous solution containing the volatile
acidic fraction is distilled and the distillate collected in three frac-
tions. If the first and third fraction, after dilution and deter-
mination of the Duclaux values, yield checking results, proof is at
hand that only one individual is present. If the first and third
fractions differ considerably in the Duclaux values, a mixture is
indicated. The results sometimes serve to identify the individual
acids.
Separation of the Amine Fraction
The basic compounds, if solid, are subjected to crystallization
and occasionally to fractional distillation; in this group, steam /I
EXAMINATION OF MIXTURES
183
distillation may aid in effecting a separation. Fractional crys-
tallization of certain salts of the amines is also of value; for this
purpose the sulfates are utilizable but for special work the platinic
chloride double salts are adaptable.
It is often important to separate the three classes of amines, and
this may be done by the application of the benzene sulfonyl
chloride reaction. Cf . page 144. ^ •
Mixture of Amines.
Add aqueous KOH and C6H6SO2CI. After completion of reaction, filter or
extract with ether.
Soluble in aque-
ous layer:
Salt of sulfonyl
derivative of
prim, amine.
Acidify to pre-
cipitate deriv-
ative of prim,
amine.
Ether layer:
Tert. amine, sulfonyl derivative of sec. amine and some
disulfonyl derivative of prim. Treat ether solution
with dilute HCl.
Soluble in HCl:
tert. amine as
hydrochloride.
Soluble in ether layer:
Sulfonyl derivative of sec. amine and
disulfonyl derivative. Evaporate
ether and warm with alcoholic
KOH to decompose disulfonyl deriv-
ative. Dilute with water.
Soluble:
Derivative of
prim, amine.
Insoluble:
Derivative of sec.
amine.
A separation similar to the above can be based upon the reac-
tion of the amines with phthalic anhydride, cf. page 62. A more
common procedure consists in the treatment of the amine fraction
with acetic anhydride, the separation of the tertiary amines by
means of dilute acid and separation of the acetyl derivatives of the
remaining members by crystallization.
Separation of the Indifferent Fraction
In work with the indifferent compounds, the physical methods
already enumerated are generally of primary importance. Chem-
ical reactions are also available. For example, a mixture boiling
184 QUALITATIVE ORGANIC ANALYSIS
at a fairly constant temperature (140-145°) consisted of a hydro-
carbon and an ester; the latter was saponified and identified by
the hydrolysis products and the hydrocarbon recovered as a pure
individual.
Cold concentrated sulfuric acid may serve often for the sep-
aration of saturated hydrocarbons from their oxygenated deriva-
tives. This reagent can be employed only when no decomposition
of the dissolved material is observed.
Dimethyl sulfate, used in connection with the classification
reactions, may be utilized also for the separation of aromatic from
saturated aliphatic hydrocarbons. Several treatments may be
required to secure a complete separation. The aromatic hydro-
carbon may be recovered from the dimethyl sulfate after saponi-
fication of the latter. (Precautions, see page 135.)
Mixtures Compounded by Nature
Many mixtures met in technical work, particularly when from
natural sources, are exceedingly complex. Fortunately, in such
instances the analyst is often supplied with information concerning
the source of the sample, the use for which it is intended, and the
claims made for the product. A separation of ingredients usually
is not essential to the identification; in fact, the analytical deter-
mination (qualitative and quantitative) of one or more typical
ingredients may furnish the required information. Moreover, in
certain lines of technical analysis, an actual separation of indi-
viduals is not necessary, but instead certain analytical procedures
are applied directly to the mixture. For example, a sample of oil
may be subjected to the following tests:
(a) Specific gravity,
(6) Melting or solidifying point,
(c) Melting-point of acids obtained by saponification,
(d) Behavior with solvents,
(e) Hehner value (insoluble fatty acids),
(/) Reichert-Meissel value (soluble acids),
(g) Saponification value,
{h) Iodine value, etc.
In dealing with technical samples, the specialized literature of the
subject must be consulted. Valuable information will be found in
EXAMINATION OF MIXTURES 185
Allen's Commercial Organic Analysis as well as in the advanced
treatises dealing with food, plant, drug, dye, physiological, and
toxicological analysis.
Exercises.
Outline in chart form procedures for the separation of the
following three mixtures:
1. An aqueous solution containing 1 per cent acetone, 5 per
cent glucose, | per cent acetic acid, and 1 per cent aniline hydro-
chloride.
2. A homogeneous liquid containing 50 per cent ethyl alcohol
and ether together with aniline, methylaniline, nitrobenzene, and
m-dinitrobenzene.
3. A solid consisting of salicylic acid, naphthalene, anthranilic
acid, /3-naphthol, diphenylamine, and sucrose.
PART C
CLASSIFIED TABLES OF COMPOUNDS
The plan for a Solubility Table was presented on page 24 of
this text and will be found illustrated in more detail in the chart
on the inside rear cover. In connection with a systematic identifi-
cation of an unknown, the chart may be consulted after the com-
pletion of the solubility tests since it may prove of aid in the choice
of suitable classification reactions. The tables of individual
compounds, however, should not be consulted until the completion
of the tests and the systematic elimination of a considerable
number of subgroups.
In the tables which follow, approximately two thousand of the
more common organic compounds are grouped in accordance
with the plan above suggested. The tables are intended only for
preliminary aid before proceeding to more advanced reference
books and the student is offered no assurance that his unknown is
included; his ability to identify unknowns is not limited to a few
thousand compounds.
In order to avoid too cumbersome a subdivision, certain sub-
groups have been united, thus Group I, subgroups 1, 2, 3, and 4
(neutral compounds) are listed in one table, the Hquids and solids
being presented separately, and subgroups 5, 6, and 7 (acidic
substances) are similarly grouped.
Since solubility tests are of qualitative character only, certain
compounds near the border line must be listed in more than one
place to avoid error. For example, several of the compounds
listed on page 189 will be reported normally " insoluble in water "
according to the standards set in Chapter VIII. Such compounds,
therefore, will be found also in the water-insoluble groups, e.g.,
Methyl isobutyrate, ethyl propionate, and n-propyl acetate are
listed in V, 5; methyl propyl ketone and diethyl ketone in V, 3, etc.
187
188 QUALITATIVE ORGANIC ANALYSIS
Halogen compounds are listed in all groups of the Solubility-
Table, together with the corresponding unsubstituted compounds
without being mentioned specifically as separate subgroups, except
under Group VI. No nitrogen or sulfur compounds are included
in Groups V and VI, but they are found in the other five groups;
elementary analysis automatically relegates an indifferent suKur
or nitrogen compound to Group VII.
A few examples will illustrate these points. Ethylene chloro-
hydrin is placed in Group I, 1, together with ethyl alcohol;
the chlorobenzoic and nitrobenzoic acids will be found in Group IV,
1, with other water-insoluble carboxyhc acids; and p-bromoanihne
is included in Group III, 1, with other water-insoluble primary
amines. p-Nitrobenzoic ethyl ester falls in Group VII, 1, and
not in Group V, 5. At the stage of the procedure where the
Solubility Table is consulted, it is only known that an indifferent
nitrogen group is present; later tests will demonstrate the presence
of another indifferent group (ester), but this need not interfere
with the classification. m-Nitroacetanilide (m.p. 154°) possesses
both a nitro and an amide group. It therefore falls under both
Group VII, 1 and Group VII, 2 and the student should consult
both groups; as a matter of fact, it will be found at both places,
but this is not essential.
The tables include practically all of the definite compounds
available on the market with the exception of salts, dyes, and
certain compounds without melting-points. (See, however, pages
198-199.) In dealing with salts the organic and inorganic con-
stituents are identified separately.
CLASSIFIED TABLES OF COMPOUNDS
189
CLASSIFIED TABLES OF COMPOUNDS
(Arranged in Accordance with the SolubiUty Table)
GROUP I. SUB-GROUPS 1, 2, 3, and 4
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
13°
0.894f
Ethylene oxide
21
0.80&f
Acetaldehyde
32
0.998f
Methyl formate
35
0.719J^
Ethyl ether
45
0.862^
Methylal
50
0.806-2/
Propionaldehyde
52
0.84
Acrolein
54
0.937f
Ethyl formate
56
0.800Y
Acetone
57
0.958^
Methyl acetate
63-4
0.794-Y
Isobutyraldehyde
64
0.879"
Dimethylacetal
66
0.792-2/
Methyl alcohol
68-70
0.882"
Isopropyl formate
73-4
0.817-2/
n-Butyraldehyde
77
0.902-2/
Ethyl acetate
78
0.785-2/
Ethyl alcohol
79
0.937f
Methyl propionate
80
O.8O520
Ethyl methyl ketone
81
0.918f
n-Propyl formate
83
0.94818
AUyl formate
83
0.789-2/
Isopropyl alcohol
83
0.7802 6
tert-Butyl alcohol, m. 25°
87-8
0.97322
Diacetyl
89
0.850°
Ethylal
90
1. 0692 2
Methyl carbonate, m. 0°
91
0.917"
Isopropyl acetate
92
O.Ollf
Methyl isobutyrate
93-4
O.8O52"
Isopropyl methyl ketone
97
0.850ff
AUyl alcohol
97
0.804^
n-Propyl alcohol
97-8
1.05-.08
Formalin (40% CH2O in water)
98
0.914"
Ethyl propionate
98
1.512^
Chloral
99
O.8I922
sec-Butyl alcohol
101
0.899-V'-
n-Propyl acetate
101
0.97423
Methyl orthoformate
101-2
0.812^5
Methyl propyl ketone
102
0.834f
Diethyl ketone
190
QUALITATIVE ORGANIC ANALYSIS
GROUP I, SUB-GROUPS 1, 2, 3, and 4r— Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
102°
0.919f
Methyl n-butyrate
102
0.81415
ier(-Amyl alcohol
103
0.831-2/
Acetal
103
0.938
AUyl acetate
108
0.80018
Isobutyl alcohol
116
0.810-2/
w-Butyl alcohol
118-9
0.824"
sec-Amyl alcohol
119
1.162i«
Chloroacetone
120
1.2362 1
a-Dichloroacetone
124
0.994-2/
Paraldehyde, m. 12°
126
0.9782 «
Ethyl carbonate
130
0.810-2/
Isoamyl alcohol
130
1.235|§
Methyl chloroacetate
132
1.223"
Ethylene chlorohydrin
134-6
1 . 154"
Methyl pyruvate
137
0.97325
Acetylacetone
144
1.118"
Methyl lactate
144 d.
Methyl bromoacetate
145
0.898-2/
Ethyl orthoformate
150-2
I.719I8
Ethylene bromohydrin
154
1.055"
Ethyl lactate
155
1.060-/
Ethyl pyruvate
155
0.947-2/
Cyclohexanone
161
1 . 159-2/
Furfural
162
1.13217
Trimethylene chlorohydrin
164
0.93125
Diacetone alcohol
167
Glycolic acetal
169
1.07311
Methyl acetoacetate
170
1 . 135f §
Furfuryl alcohol
172
0.96715
Pinacone m. 35°
174
2.65217
Bromal
176
1.3661''
Glycerol a-dichlorohydrin
181
1.16015
Methyl malonate
182
/3-Hydroxj'ethyl acetate
182
1.380"
Glycerol /3-dichlorohydrin
186
1.0792/
Ethyl oxalate
191
1.0522 0
Methyl levulinate
195
1.11725
Methyl succinate, m. 18°
207
1.057-1/
7-Valerolactone
208
1.108"
/3- Angelica lactone
210
1.07019
Trimethylene glycol diacetate
100-110/185 mm.
Trimethylene bromohydrin
258
1.16111
Triacetin
260
1.17615
Diacetin
CLASSIFIED TABLES OF COMPOUNDS
191
GROUP I. SUB-GROUPS 1, 2, 3, and 4
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
12°
124°
Paraldehyde
18
195
Methyl succinate
25
83
tert-Butyl alcohol
35
172
Pinacone
44
Bromal alcoholate
48
280
Methyl tartarate
53
Bromal hydrate
55
115
Chloral alcoholate
56
Pinacone hydrate
59
97 d.
Chloral hydrate
79
284 d.
Methyl citrate
83-4
Benzoyl carbinol
86
o-Hydroxybenzyl alcohol
86
Diglycolide
116
Benzoquinone
128
255
Lactide
GROUP I. SUB-GROUPS 5*, 6, and 7
Liquids
BOILING-POINT
SPECIFIC-GRAVITY
NAME OF COMPOUND
32°
0.998f
Methyl formate
54
0.948f
Ethyl formate
55
1 . 105-2^
Acetyl chloride
57
0.958f
Methyl acetate
60
1.0621"
Chloromethyl ether
63-4
Oxalyl chloride
71
1.2361 ^
Methyl chloroforraate
79
Chloromethylethyl ether
80
1.064-Y-
Propionyl chloride
81
1.529
Acetyl bromide
92
1.017-2/
Isobutyryl chloride
94
1.139|§
Ethyl chloroformate
97
a-Chloroethyl ether
100
1.245f
Formic acid
100
1.028-2/
n-Butyryl chloride
105
1.495"
Chloroacetyl chloride
105
1.31520
a, a'-Dichloromethyl ether
115
0.989-2/
Isovaleryl chloride
116
1.13712
a, a'-Dichlorodiethyl ether
* Aldehydes (see I, 2) may also show acid reaction due to the presence of
oxidation products.
192
QUALITATIVE ORGANIC ANALYSIS
GROUP I. SUB-GROUP 5, 6 and 7— Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OP COMPOUND
118°
1.054-1^
Acetic acid, m. 16°
127 (?)
1.913»
Chloroacetyl bromide
127
1.908"
Bromoacetyl chloride
138
1.079^^
Acetic anhydride
140
1.062Y
Acrylic acid
140
0.994f^
Propionic acid
144 d.
1.13911
Propiolic acid
149
2.31721
Bromoacetyl bromide
155
0.950^/
Isobutyric acid
163
0.960-1-^
n-Butyric acid
168
1.0171=
Propionic anhydride
165 d.
1.28818
Pyruvic acid
169 d.
1.018^5
Isocrotonic acid
176
0.93120
Isovaleric acid
186
1.28"
a-Chloropropionic aicd
189
1.57213
Dichloroacetic acid
190 d.
1.41215
Succinyl chloride, m. 16°
205
a-Bromopropionic acid, m. 24°
250 d.
1 . 139-2/
Levulinic acid
GROUP I. SUB-GROUPS 5, 6 and 7
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
13°
165° d.
Pyruvic acid
16
118
Acetic acid
16
190 d.
Succinyl chloride
24
205
a-Bromopropionic acid
33
250 d.
Levulinic acid
42
/3-Chloropropionic acid
42
180
Phenol
50
208
Bromoacetic acid
54
163
Methyl oxalate
57
195
Trichloroacetic acid
58
288 d.
Orcinol (hydrate)
61-2
/3-Bromopropionic acid
63
185
Chloroacetic acid
64
227 d.
a, j3-Dibromopropionic acid
66
d.
Cyanoacetic acid
72
182
a-Crotonic acid
78-9
d.
Glycolic acid
82
/3-Iodopropionic acid
84
lodoacetic acid
CLASSIFIED TABLES OF COMPOUNDS
193
GROUP I. SUB-GROUPS, 5, 6 and 7— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
96°
285° d.
Phenoxyacetic acid
100-10 d.
Peracetic acid
104
245 d.
Catechol
105
272/ 100 mm.
n-Pimelic acid
106
263 d.
Chlorohydroquinone
107
289
Orcinol (anhydrous)
110
Bromohydroquinone
110
280
Resorcinol
111
d.
Ethylmalonic acid
117 d.
Benzylmalonic acid
118
dZ-Mandelic acid
124
Trichlorolactic acid
124
Toluhydroquinone
130
d.
Maleic acid
133
( d-Mandelic acid
I ^Mandelic acid
133
293 d.
Pyrogallol
133 d.
d.
Malonic acid
135 d.
Methylmalonic acid
150
Protocatechuic aldehyde
169
285
Hydroquinone
178-9
Acetylenedicarboxylic acid
189
235 d.
Succinic acid
218
Phloroglucinol
GROUP I. SUB-GROUP 8
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OP COMPOUND
-6°
0.699-1"
Methylamine
3.5
0.662-5
Trimethylamine
7
0.686-«
Dimethylamine
19
0.68915
Ethylamine
33
0.69018
Isopropylamine
49
0.71820
n-Propylamine
55
0.71215
Diethylamine
58
0.76915
Allylamine
63
0 1820
scc-Butylamine
68-9
0.73615
Isobutylamine
76-7
0.74215
n-Butylamin2
95
0.75018
Isoamylamine
103
0.76619
n-Amylamine
105
0.860^
Piperidine
110
0.74315
Di-n-propylamine
194
QUALITATIVE ORGANIC ANALYSIS
GROUP I. SUB-GROUP Sr-Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
111°
Diallylamine
116
0.97611
Pyridine
129
0.949J^
a-Picoline
133
/3-DimethyIaminoethyl alcohol
134
0.8620
Cyclohexylamine
143-50
0.928^*
Piperylhydrazine
161
/3-Diethylaminoethyl alcohol
184
0.986i|
Benzylamine
189
0.920*
7-Diethylaminopropyl alcohol
250
1.011-2/
Z-Nicotine
GROUP I. SUB-GROUP 8
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
41-2°
143°/i8min.
Cyanamide
63
282
TO-Phenylenediamine
80 d.
2, 4-Diaminophenol
85
A^-Methyl-p-aminophenol
102
256
o-Phenylenediamine
104
145
Piperazine
122
m-Aminophenol
140
267
p-Phenylenediamine
170
o-Aminophenol
GROUP I.
SUB-GROUP 9
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OP COMPOUND
17°
0.90015
Ethyl nitrite
65 di
1.217^
Methyl nitrate
81
0.789^5
Acetonitrile
87
1.116^=
Ethyl nitrate
97
0.7802 0
Propionitrile
101
1.1441s
Nitromethane
107-8
Isobutyronitrile
120
Acetone cyanohydrin
152 d.
0.920|f
Ethyl methyl ketoxime
182 d.
Lactonitrile
192-5 d.
1.337-V-
Formamide, m. 3°
222
1.02411
Formyl piperidine
226
1.011»
Acetyl piperidine
286
0.99515 1
Trimethylene cyanide
CLASSIFIED TABLES OF COMPOUNDS
GROUP I. SUB-GROUP 9
Solids
195
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
46°
284°
Formanilide
47
114
a-Acetaldoxime
50
184
Ethyl carbamate (Urethane)
52
177
Methyl carbamate
54
265 d.
Succinonitrile
59
195
n-Propyl carbamate
60
135
Acetoxime
61
215-20 d.
Trichlorolactonitrile
74-5
Diacetylmonoxime
79
213
Propionamide
81-2
d.
Phenyl hydroxj'lamine
82
222
Acetamide
113
Antipyrine
114
Chloralformamide
115
216
n-Butyramide
125-6
287
Succinimide
128
216
Isobutyramide
GROUP I. SUB-GROUP 10
Liquids
MELTING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
36°
93
188
0.839-^"-
1.0741"
1.3315
Ethyl mercaptan
Thioacetic acid
Methyl sulfate
GROUP I. SUB-GROUP 10
Solids
MELTING-POINT
NAME OF COMPOUND
78°
83-^
109 subl.
Allyl thiocarbamide
Benzenesulfinic acid
Dimethyl sulfone, b. 238°
196
QUALITATIVE ORGANIC ANALYSIS
GROUP II. SUB-GROUP 1
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
18°
119°/l2min.
d/-Lactic acid
43
255
a-Hydroxybutyric acid
79
Glycolic acid
80
Citraconic acid
97
302 d.
Glutaric acid
100
Citric acid (hydrated)
100
Z-Malic acid
101
Oxalic acid (hydrated)
130
Maleic acid
132
dWVIalic acid
140-3
i-Tartaric acid
153
Citric acid (anhydrous)
161
Itaconic acid
169
d-Tartaric acid
185
235 d.
Succinic acid
189
Oxalic acid (anhydrous)
190 d.
Aconitic acid
205-6
d^Tartaric acid
212 d.
Mucic acid
GROUP II. SUB-GROUP 2
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
188°
1.0402 0
Propylene glycol
197
1.113|f
Ethylene glycol
210-5 d.
1.338"
Glycerol a-chlorohydrin
216
1.05218
Triraethylene glycol
220-40
Glycerol a-bromohydrin
260
1.17911
Diacetin
260-70
1 -22111
Monoacetin
290 d.
1.260-2/
Glycerol
CLASSIFIED TABLES OF COMPOUNDS
GROUP II. SUB-GROUP 2
Solids
197
MELTING-POINT
NAME OF COMPOUND
85-90°
Dextrose (hydrated)
95
Laevulose (d-Fructose)
95-7
Glycolic aldehyde
95-105
Rhamnose
110 d.
d-Glucosamine
110-20
Raffinose (hydrated)
118-9
Raffinose (anhydrous)
132
d-Mannose
144-5
i-Xylose
146
Glucose
160
Z-Arabinose
165
a-Methyl-d-glucoside
166
d-Mannitol
170
d-Galactose
171-2 subl.
Polyoxymethylene
175
Helicin (glucoside)
178 d.
Inulin
185
Saccharose
201
Salicin
203 d.
Lactose
214
# ■
Amygdalin
225
t-Inosite
234
d-Quercite
240° d.
Glycogen
253
Pentaerythrite
d.
Isomaltose
d.
Maltose
Dextrins
(Some glucosides are listed under V, 1.)
GROUP II. SUB-GROUP 3
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
171°
/3-Aminoethyl alcohol
286
Trimethylene cyanide
3°
192-5 d.
Formamide
10
116
Ethylenediamine
44
Piperazine hydrate
54
265 d.
Succinonitrile
198
QUALITATIVE ORGANIC ANALYSIS
GROUP II. SUB-GROUP S— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
59°
Triacetoneamine (hydrate)
62
Tetramethyl ammonium hydroxide
63
282°
m-Phenylenediamine
79
213
Propionamide
80 d.
2, 4-Diaminophenol
82
222
Acetamide
91-4
Acetaldehyde ammonia
101-2
d.
Methyl urea
102
256
o-Phenylenediamine
104
145 (?)
Piperazine
105
Dicyanodiamine (guanyl urea)
nod.
(/-Glucosamine
113
Antipyrine
115
216
n-Butyramide
122
7M-Aminophenol
125-6
287-8
Succinimide
128
216
Isobutyramide
132
Carbamide (urea)
140
267
p-Phenylenediamine
170
o-Aminophenol
170
Malonamide
180
s-Acetyl methyl urea
190 d.
Biuret
190 d.
Tetraethyl ammonium hydroxide
195 d.
^/-Alanine
205
Dicyanodiamide
216
Hydantoin
218
Acetyl urea
226 d.
( d-Asparagine
\ Z-Asparagine
232 d.
GlycocoU
232-40 d.
Choline
234
Caffeine
242 d.
Succinamide
243
Parabain
220+subl.
a-Aminoisobutyric acid
270 d.
Z-Aspartic acid
280
Hexamethylenetetramine
d.
Barbituric acid
Creatinine
Guanidine
Alloxan
Betain
CLASSIFIED TABLES OF COMPOUNDS
199
GROUP II. SUB-GROUP 4
Solids
MELTING-POINT
NAME OP COMPOUND
43-4°
Benzenesulfonic acid (hydrate)
65
Benzenesulfonic acid (anhydrous)
78-9
/3-Naphthalenesulfonic acid (trihydrate)
85
Sulfoacetic acid
85-90
a-Naphthalenesulfonic acid
92
p-Toluenesulfonic acid
100+
2, 5-Dichlorobenzenesulfonic acid
120
1, 2, 5-Sulfosalicj^lic acid
122 d.
2-Naphthol-6-sulfonic acid
170 d.
l-Naphthol-4-sulfomc acid
170-4
Thiourea
195 d.
d-Camphorsulfonic acid
p-Phenolsulfonic acid
/3-Naphthalenesulfonic acid (anhydrous)
259
p-Sulfobenzoic acid
2-Naphthol-3, 6-Disulfonic acid
2-Naphthol-6, 8-Disulfonic acid
•
Many other sulfonic acids, alkyl sulfuric
acids, etc., usually met as salts. Cf.
List in Eastman Catalogue of Organic
Chemicals.
200
QUALITATIVE ORGANIC ANALYSIS
GROUP III. SUB-GROUPS 1, 2, 3
Liquids
BOILING POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
89°
0. 72511
Triethylamine
110
0.73625
Di-n-propylamine
150-5
0.809^5
Triallylamine
153
0.750|f
Tri-n-propylamine
160
Di-n-butylamine
170
0.8442 0
d-Coniine
183
1.02111
Aniline
180-5
n-Octylamine
185
0.929-^
Dimethyl-o-toluidine
185
Methyl benzylamine
185
Dimethyl benzylamine
187
0.76611
Diisoamylamine
192
0.985ff
Methylaniline
193
0.958^
Dimethylaniline
199
0.996ff
o-Toluidine
199
Ethyl benzylamine
201
Ethylmethylaniline
203
0.989^
OT-Toluidine
205
0.963^
Ethylaniline
205
0.8620
Z-Menthylamine
207
1.213^
o-Chloroaniline
208
AT-Methyl-p-toluidine
210
0.92920
Dimethyl-p-toluidine
211
0.77820
Tri-n-butylamine
212
0.91815
1, 3-Dimethyl-4-aminobenzene
215
0.980^5
1, 4-Dimethyl-2-aminobenzene
218
0.935^
Diethylaniline
lOl-2/io mm.
AT-Ethyl-p-toluidine
124/i6mm.
A''-Ethyl-o-toluidine
220-5
1.098^5
o-Anisidine (o-Methoxyaminoben-
zene)
222
0.949^8
n-Propylaniline
229
0.96218
Mesidine
229
o-Phenetidine
230
1.216^
?n-Chloroaniline
236
n-Butylaniline
129/13 mm.
Methyl A'^-methylanthranilate
239
1.09520
Quinoline
CLASSIFIED TABLES OF COMPOUNDS
GROUP III. SUB-GROUPS 1, 2, ^— Continued
201
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
240°
1.099-2^
Isoquinoline, m. 24°
240
3- Bromo-4-aminotoluene
241-45
0.91020
Di-n-propylaniline
139-40/15 mm.
Di-n-butylaniline
246
1.101^°
Quinaldine
245-50
1 -05611
Tetrahydroquinoline
250
o-Bromoaniline, m. 31°
251
1.5822 0
/ra-Bromoaniline, m. 18°
254
0.928J^
Isoamylaniline
254
1.061^5
p-Phenetidine
258
1.068^
6-Methyl quinoline
250-60 d.
1.16815
Methyl anthranilate
260-5
Ethyl anthranilate, m. 13°
264
1.06115
2, 4-Dimethyl quinoline
288
Benzyl ethylaniline
293
Methyl a-naphthylamine
294
Ethyl TO-aminobenzoate
296
I.O48-24O
Methyl diphenylamine
298
1.06715
Benzylaniline
300
1. 03311
Dibenzylamine
304-5 d.
1.15420
6-Methoxyquinoline
305-6
Benzyl methylaniline
GROUP III. SUB-GROUPS 1, 2, 3
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
13°
2600
Ethyl anthranilate
15
215-20
Amino-p-xylene
18
251
m-Bromoaniline
20
250
Tetrahydroquinoline
24
240
Isoquinoline
24.5
135/]5mm.
Methyl anthranilate
25-7
m-Iodoaniline
26
240
3- Bromo-4-aininotoluene
28
140/10 mm.
6-Methoxyquinohne
31
250
o-Bromoaniline
32
298
Benzylaniline
202 QUALITATIVE ORGANIC ANALYSIS
GROUP III. SUB-GROUPS 1, 2, 3— Continued
MELTING-POINT
BOILING-POINT
NAMK OF COMPOUND
41°
262°
l-Dimethylamino-4-aminobenzene
45
200
p-ToIuidine
48
Tetramethyl p-phenylenediamine
49
226
1, 2, 4-Xylidine
50
300
a-Naphthylamine
51
Procaine base
52
253-4
Indol
56
o-Iodoaniline
57
243
p-Anisidine
58
260
4-Phenyl morpholine
60
260-5
2, 6-Dimethyl quinoliae
60
280-5
m-Nitrodimethylaniline
62
p-Iodoaniline
63
283
m-Phenylenediamine
63
245
2, 4-DichloroaniIine
64
Diphenylethylenediamine
66
p-Bromoaniline
68
235
Pseudocumidine
70
300 d.
Dibenzylaniline
70
232
p-Chloroaniline
71
o-Nitroaniline
72
2-Nitro-p-toluidine
73
p-Dimethylaminobenzaldehyde
74
Ethyl phenylcinchoninate
75
266
8-Hydroxyquinoline
74-6
165/30 mm.
p-Dimethylaminophenol
75-80
Benzamidine
77
262
s-Trichloroaniline
79
2, 4-Dibromoaniline
82
300+
/3-Naphtha quinaldine
84
p-Nitrosodiet hylaniline
85-90
o-Methylaminophenol
85
p-MethylaminophenoI
85
265-8
m-DimethylaminophenoI
85
p-Nitroscdimethylaniline
86-8
2, 4-Diaminochlorobenzene
88-90
pp'-Diaminodiphenylmethane
89
Ethyl-p-aminobenzoate
90-1
Tetramethyldiaminodiphenyl-
methane
CLASSIFIED TABLES OF COMPOUNDS 203
GROUP III. SUB-GROUPS 1, 2, 3— Continued
MELTING-POINT
BOILING-POINT
91°
91
95
98
99-100
102
260
102
256
106
293-5
107
107
360+
111-2
300
114
285
114
114+
114-6
115
116
117
120-1
122
125
360
126
127
400
127
129
129
130 d.
136
138
140
267
141
144
144
145
147
147
149
155
162
163
NAME OF COMPOUND
Tribenzylamine
6-Nitro-o-toluidine
3-Nitro-o-toluidine
Z-Cocaine
2-Amino-5-azotoluene
Methyl acetanilide
o-Phenylenediamine
p-Aminoacetophenone
4-Nitro-2-aminotoIuene
Acridine
/3-Naphthylamine
m-Nitroaniline
3-Nitro-p-tolmdine
p-Nitrosomethylaminobenzoate
p-Nitrosomethylaniline
Atropine (dZ-Hyoscyamine)
3-Nitro-4-aminotoluene
p-Dimethylaminoazobenzene
s-Diphenylethylenediamine
TO-Aminophenol
p-Aminoazobenzene
Phenylglycine
Benzidine
5-Nitro-2-aniinotoluene
Methyleneaminoacetonitrile
o-Tolidine
Leucomalachite green
Picolinic acid
2, 6-DinitroaniIine
p-Phenylenediamine
Orthoform
Anthranilic acid
2-Nitro-l-aminonaphthalene
a-Triphenylguanidine
p-Nitroaniline
Papaverine
6-Nitroquinoline
Z-Codeine
p-Aminoacetanilide
p-Nitrodimethylaniline
204 QUALITATIVE ORGANIC ANALYSIS
GROUP III. SUB-GROUPS 1, 2, S— Continued
MELTING-POINT
NAME OF COMPOUND
163°
Diphenylpiperazine
164
6-Nitroquinaldine
170 d.
di-a-Amino-n-caproic acid
170
o-Aminophenol
171
Quinidine (dextro)
171-3
Diacetyl morphine
173
5-Amino-o-cresol
174
Tetramethyldiaminobenzophenone
174
w-Aminobenzoic acid
175
Quinine (iBevo)
176
Narcotine (lajvo)
178
Brucine (Isevo)
180
2, 4-Dinitroaniline
184 d.
p-Aminophenol
186
p-Aminobenzoic acid
199
2-Hydroxyquinoline
205 (180)
Veratrine
207
Cinchonidine
234 d.
d- and ^Asparagine
228-30
Nicotinic acid
230
Quinolinic acid
235
Caffeine
250
Morphine (Isevo)
250-5
i-Aminoanthraquinone
256 subl.
dZ-Phenylaminoacetic acid
263+ d.
di-Phenylalanine
265
Cinchonine (dextro)
268
Strychnine (laevo)
302
2-Aminoanthraquinone
280-300 d.
p-Aminobenzenesulfonic acid (Sul-
fanilic acid)
310 subl.
Isonicotinic acid
314-8 d.
Z-Tyrosine
d.
5-Aminosalicylic acid
Creatin
Melamine
subl.
fW-a-Aminocaprylic acid
subl.
<iZ-«-Amino-7i-valeric acid
Guanine
CLASSIFIED TABLES OF COMPOUNDS
205
GROUP III. SUB-GROUP 4
Liquids
BOILING-POINT
MELTING-POINT
NAME OF COMPOTJND
227° d.
243
17°
as-Methylphenylhydrazine
Phenylhydrazine
GROUP III. SUB-GROUP 4
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
44°
61
106
157 d.
210 d.
220-5 d.
220°/40mm.
240-4 d.
as-Diphenylhydrazine
p-Tolylhydrazine
p-Bromophenylhydrazine
p-Nitrophenylhydrazine
Anthraquinonylhydrazine
p-Hydrazinobenzoic acid
206
QUALITATIVE ORGANIC ANALYSIS
GROUP IV. SUB-GROUP 1
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
176°
0.9312 0
Isovaleric acid
185
0.94120
n- Valeric acid
191
0.97815
n-Butyric anhydride
205
a-Bromopropionic acid m. 24°
205
0.929^
n-Caproic acid
207
0.925-2J1
Isocaproic acid
212-7 d.
1.5415
a-Bromo-n-butyric acid
97-105/10 mm.
a-Bromo-n-valeric acid
232
1.048J^
Hexahydrobenzoic acid, m. 30°
236
0.914-2/
n-Caprylic acid, m. 16°
268-70
0.930f|
Capric acid, m. 30°
275 d.
0.91025
Undecenoic acid, m. 24°
GROUP IV. SUB-GROUP 1
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
14°
285°/ 100 mm.
Oleic acid
16
236
«-Caprylic acid
24
275 d.
Undecenoic acid
—
168/i2mm.
Undecanoic acid
24
205
a-Bromopropionic acid
30
232
Hexah3'drobenzoic acid
30
268-70
Capric acid
42
360
Benzoic anhydride
43
225/100 mm.
Laurie acid
48
280
Hydrocinnamic acid
51
234/15 mm.
Elaidic acid
53-4
250/100 mm.
Myristic acid
62
340-50 d.
Palmitic acid
69
360-80
Stearic acid
76
262
Phenylacetic acid
96
285 d.
Phenoxyacetic acid
98
250 d.
Methyl ether salicyhc acid
102
259
o-Toluic acid
105
272/100 mm.
PimeUc acid
106
360 d.
Nonanedicarboxylic acid (Azelaic)
110
263
m-Toluic acid
CLASSIFIED TABLES OF COMPOUNDS
GROUP IV. SUB-GROUP 1— Continued
207
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
117° d.
Benzylmalonic acid
121
249°
Benzoic acid
126
Phenylglycine
131
284
Phthalic anhydride
132-4
230 d.
Pyromucic acid
133
295/100 mm.
Sebacic acid
133
299 d.
Cinnamic acid
135
Acetylsalicylic acid
136
Dihydroxy stearic acid
136
Picolinic acid
136
Phenylpropiolic acid
140
o-Chlorobenzoic acid
140
m-Nitrobenzoic acid
140
Suberic acid
144
Anthranilic acid
146
o-Nitrobenzoic acid
148
o-Bromobenzoic acid
■ 148-9
Oxanilic acid
150
Benzilic acid
151
4-Hydroxy-m-toIuic acid
152
Adipic acid
152
p-Nitrophenylacetic acid
155
m-Bromobenzoic acid
157
Salicylic acid
158
m-Chlorobenzoic acid
158
o-Aminocinnamic acid
162
o-Iodobenzoic acid
162
a-Naphthoic acid
163
2-Hydroxy-m-toluic acid
163-5
di-Benzoyl alanine
170 d.
dZ-a-Amino-n-caproic acid
172-4
Acetylphenylglycine
174
m-Aminobenzoic acid
174-5
Propyl Red
175
p-Aminocinnamic acid
177
p-Toluic acid
179
2, 4-Diiiitrobenzoic acid
179
iV-Methyl anthranilic acid
181-2
Methyl Red
184
Anisic acid
185
/3-Naphthoic acid
185
Acetylanthranilic acid
208 QUALITATIVE ORGANIC ANALYSIS
GROUP IV. SUB-GROUP 1— Continued
MELTING-POINT
186°
187
187
190-200 d.
140 d.-191
194
196 d.
196
200
200+ subl.
200-20 d.
204
206
207
207
210
213
213-4
216
216
220 d.
220-5 d.
220+ d.
230 d.
228-30
230
237
237-8 d.
238
242 d.
242
245 d.
249-50
252 d.
250 d.
251
256+ subl.
263+ d.
265
274
285
NAME OF COMPOUND
p-Aminobenzoic acid
d-Camphoric acid
Hippuric acid
o-Phthalic acid
3, 6-Dichlorophthalic acid
Acetylphenylglycine
Protocatechuic acid
m-Nitrocinnamic acid
m-Hydroxybenzoic acid
Fumaric acid
Tannic acid
3, 5-Dinitrobcn,zoic acid
p-Coumaric acid
o-Coumaric acid
Vanillic acid
Phenyl cinchoninic acid
p-Hydroxybenzoic acid
p-Cyanobenzoic acid
2-Hydroxy-3-naphthoic acid
Piperic acid
2, 4, 6-Trinitrobenzoic acid
p-Hydrazinobenzoic acid
Gallic acid
d- and Z-Asparagine
Nicotinic acid
Quinolinic acid
o-Nitrocinnamic acid
dZ-a-Aminophenylacetic acid
p-Nitrobenzoic acid
Methylenedisalicylic acid
p-Chlorobenzoic acid
p-Hydroxyphenylglycine
Acetyl-7w-aminobenzoic acid
Acetyl-p-aminobenzoic acid
Tetrachlorophthalic acid
p-Bromobenzoic acid
dZ-Phenylaminoacetic acid
dZ-Phenylalanine
p-Iodobenzoic acid
Naphthalic acid
p-Nitrocinnamic acid
CLASSIFIED TABLES OF COMPOUNDS
GROUP IV. SUB-GROUP 1— Continued
209
MELTING-POINT
NAME OF COMPOUND
300°
IsophthaUc acid
310 subl.
Isonicotinic acid
314+ d.
Z-Tyrosine
300+ subl.
Terephthalic acid
330
a-Naphthophthalein
subl.
dZ-«-Amino-n-valeric acid
di-«-Aininocaprylic acid
, 5-AminosaIicylic acid
GROUP IV. SUB-GROUP 2
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
175°
o-Chlorophenol, m. 7°
190
1.05111
o-Cresol, m. 31°
194-5
o-Bromophenol
196
1.165ff'
Salicylaldehyde
202
1.039|f
p-Cresol, m. 36°
202
1.039if
TO-Creso]
205
1.1530
Guaiacol, m. 28°
211
1.036"
1, 3, 4-XylenoI, m. 26°
214
m-Chlorophenol, m. 28°
224
1.189if
Methyl salicylate
230
1.1842 0
Ethyl salicylate
236
m-Bromophenol, m. 32°
237
0.978f^
Carvacrol
238 d.
1.098^^5
n-Propyl salicylate
243
1.070*
Resorcinolmonomethyl ether
250
1.069|f
Eugenol
250
1.06515
Isoamyl salicylate
153/10 mm.
Resorcinol monacetate
267
1.090|f
Isoeugenol
'H£MTERN«N[VEB8m'i
210
QUALITATIVE ORGANIC ANALYSIS
GROUP IV. SUB-GROUP 2
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
26°
211°
1, 3, 4-Xylenol
28
205
Guaiacol
28
214
7n-Chlorophenol
31
190
o-Cresol
32
236
7«-Bromophenol
36
202
p-Cresol
37
217
p-Chlorophenol
42
180
Phenol
42
172/12 nun.
Phenyl salicylate
45
214
o-Nitrophenol
49
211
1, 3, 2-Xylenol
50
232
Thymol
52-3
236
6-Chloro-m-cresol
53
243
Hydroquinonemonomethyl ether
60
1, 2-Dihydroxynaphthalene
63
236
p-Bromophenol
65
225
1, 2, 4-Xylenol
67
244
s-Trichlorophenol
68
219
Hydroxymesitylene
70
Methyl /rt-hydro.\ybenzoate
71
234
Pseudocumenol (1, 2, 4-Trimethyl-
5-hydroxybenzene)
72
282
wi-Hydroxyethylbenzoate
74
211
1, 4, 2-Xylenol
75
266
8-Hydroxyquinoline
74-6
165/30 mm.
p-Dimethylaminophenol
80
285
Vanillin
80 d.
o-Methylaminophenol
81
2-Hydroxy-l-naphthylaldehyde
85
p-Methylaminophenol
85
265-8
7rt-Dimethylaminophenol
93
/«-Nitrophenol
94
278-80
a-Naphthol
96
vS-Tribromophenol
104
Tw-Hydroxybenzaldehyde
109
a-N itroso-/3-naphthol
110
Bromohydroquinone
114
p-Nitrophenol
114
2, 4-Dinitrophenol
115
p-Hydroxybenzaldehyde
116
298
p-Hydroxyethylbenzoate
CLASSIFIED TABLES OF COMPOUNDS
GROUP IV. SUB-GROUP 2— Continued
211
MELTING-POINT
NAME OP COMPOUND
122°
122
122
125 d.
128-30
131
140
140
147-8 d.
150
150
151
152
162
165
166
168
168-9
169-70
170
170
170-90
171
171
173
176
181
184 d.
185
190
192 d.
199
201
204
210
210-11
213
218
250-3
289
290+
Picric acid
^-Naphthol
m-Aminophenol
p-Nitrosophenol
Benzeneazo-o-cresol
p-Hydroxymethylbenzoate
Salicylamide
1, 8-Dihydroxy naphthalene
/3-Nitroso-a-naphthol
Ethyl gallate
Protocatechuic aldehyde
4-Hydroxy-m-toluic acid
p-Hydroxyazoxybenzene
p-Hydroxybenzamide
Arbutin (Glucoside)
N-Acetyl-p-aminophenol
2, 4-Dinitro-6-aminophenol
N-Acetyl-p-methylanunophenol
Dichlorohydroquinone
o-Aminophenol
TO-Hydroxybenzamide
Aurin
Quinhydrone
o-Azophenol
5-Amino-2-hydroxytoluene
1, 4-Dihydroxy naphthalene
1, 4-Naphtholaldehyde
p-Aminophenol
p-BenzalaminophenoI
1, 4-Nitrosonaphthol
Thymolphthalein
2-Hydroxyquinoline
N-Acetyl-o-aminophenol
p-Azophenol
Tetrabromo-o-cresol
5-Benzalamino-o-cresoI
o-Cresolphthalein
Phloroglucinol
Phenolphthalein
Alizarin
Fluorescein
212
QUALITATIVE ORGANIC ANALYSIS
GROUP IV. SUB-GROUP 3
Solids
MELTING-POINT
NAME OF COMPOIND
172°
Phenyl ethyl barbituric acid
188
Diethyl barbituric acid
200
Isatin
230 d.
Nitroguanidine
233
Phthalimide
d.
Nitro urea
270
Theophyllin
300 subl.
Theobromine
Cyanuric acid
Uric acid
GROUP IV. SUB-GROUP 4
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
101°
114
130
226 d.
1.14415
1.05615
1.022^
1.1602 0
Nitromethane
Nitroethane
n-Nitropropane
Phenylnitromethane
GROUP IV. SUB-GROUP 4
Solids
MELTING-POINT
NAME OF COMPOUND
33-5°
a-Benzaldoxime
59
Acetophenone oxime
82
Trinitrotoluene
109
a-Nitroso-/3-naphthol
120
d-Camphor oxime
125
p-Nitrosophenol
140
Benzophenone oxime
144
p-Nitrosodiphenylamine
235
Diacetyldioxime(Dimethylglyoxime)
237 d.
a-Benzildioxime
CLASSIFIED TABLES OF COMPOUNDS
213
GROUP IV. SUB-GROUP 5
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
170°
Thiophenol
195
7«-Thiocresol
15°
194
o-ThiocresoI
24
— d.
Thiobenzoic acid
43
194
p-Thiocresol
81
28G
/3-Thionaphthol
83-4
Benzenesulfinic acid
85
p-Toluenesulfinic acid
88
Benzenesulfonyl benzylamine
95
Benzenesulfonyl-?«-toluidine
101
p-Toluenesulfonylaniline
104
Benzenesulfonyl-o-nitraniline
112
SuKanilide
112
Benzenesulfonylaniline
115
Thiobenzamide
117
p-Toluenesulfonyl-p-toluidine
120
Benzenesulfonyl-p-toluidine
121
Benzenesulfonyl-p-chloroaniline
124
Benzenesulfonyl-o-toluidine
132
Benzenesulfonyl-m-nitraniline
136
p-ToIuene sulfonamide
139
Benzenesulfonyl-7>nitraniline
150
a-Napthalenesulfonamide
154
o-ToIuene sulfonamide
156
Benzenesulfonamide
157
Phenylthiohydantoic acid
164
Thiosalicylic acid
217
|3-Napthalenesulfonamide
220 d.
o-Benzoic sulfimide (Saccharin)
240 d.
Thiobarbituric acid
Z-Cystine
Many sulfonic acids, such as sul-
fanilic, aminonaphthalene sulfonic,
etc.
Sulfonephthaleins, such as phenol-
sulfonephthalein, thymolsulfone-
phthalein, dibromothymolsulfone-
phthalein, o-cresolsulfonephthalien
etc.
214
QUALITATIVE ORGANIC ANALYSIS
GROUP IV. SUB-GROUP 6
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
169°
181
1.081^^
1.026-Y-
Methyl acetoacetate
Ethyl acetoacetate
GROUP IV. SUB-GROUP 6
Solids
MELTING-POINT
BOILING- POINT
NAME OF COMPOUND
60°
80
108-9
262-4°
270
Benzoylacetone
Dibenzoylmethane
Dehydracetic acid
CLASSIFIED TABLES OF COMPOUNDS
215
GROUP V. SUB-GROUPS 1, 2, 3
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
92
0.804^5
Isovaleraldehyde
100-1
0.814^5
tert-Amyl alcohol
101
0.81215
Methyl propyl ketone '
102
0.833f
Diethyl ketone
103
0.818^1
?i-Valeraldehyde
10)
0.826°
Pinacoline
116
1.203f
a-Epichlorohydrin
116-8
Methyl n-propjl carbinol
118
0.823»
sec- Ainyl alcohol
119
0.8031"
Lsobutyl methyl ketone
124
0.994-Y-
Paraldehyde, m. 12°
127-8
0.8332 0
n-Hexjd aldehyde
129-31
0.81020
Isoamyl alcohol
130
0.858-2^1
Mesityl o.xide •
130-1
0.9423J-
Cyclopentanone
136
0.833°
sec-Hexyl alcohol
136-9
7i-Butyl methyl carbinol
137
O.8I720
7i-Amyl alcohol
139
0.94021
Cyclopentanol
142
Triethyl carbinol
151
0.837°
Methyl 7i-amyl ketone
155
0.947-^
Cyclohexanone
155-6
0.849^
7i-Heptylaldehyde
157-8
0.82020
7i-Hexyl alcohol
160
0.944
Cyclohexanol, m. 16°
165-70
Methyl cyclohexanols
175-6
0.830i«
7i-Heptyl alcohol
176
1.39616
Glycerol a-dichlorohydrin
179
0.819-2^
sec-Octyl alcohol
179
l.OSO-V^-
Benzaldehyde
179-81
0.969°
Cycloheptanone
180
7i-Hexyl methyl carbinol
182
1.380°
Glycerol /3-dichlorohydrin
94-5/15 mm.
Di-7i-butyl carbinol
190-5
0.8702°
Z-Linalool
192
0.837°
7i-0ctyl alcohol (primary)
198
0.885-2^^
Phorone, m. 28°
199
1.02422
7«-Toluylaldehyde
98-100/35 mm.
Para 7i-butyraldehyde
216 QUALITATIVE ORGANIC ANALYSIS
GROUP V. SUB-GROUPS 1, 2, 3— Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
200°
0-Toluylaldehyde
200
1.0232 5
Acetophenone, m. 20°
203
1.013
Methyl phenyl carbinol
205
1.050|f
Benzyl alcohol
205-^
0.8562 0
Citronellal
207
0.8962 0
Z-Menthone
114-8/ 15 mm.
Tri-7i-butyl carbinol
213-4
1.29^
o-Chlorobenzaldehyde
213-4
7n-Chlorobenzaldehyde, m. 17°
218
0.93520
Terpineol, m. 35°
219
1.02415
;3-Phenylethjd alcohol
219
2.168"
Glycerol-/J-dibromohydrin
219 d.
2.1118
Glycerol-a-dibromohydrin
220 d.
1.050-2^
Cinnamaldehyde
222
1.013
Methyl-;j-tolyl ketone
224-8 d.
0.897^5
Citral
113-4/15 mm.
0.86120
Rhodinol
229
0.88315
Geraniol
231
0.8391
n-Decyl alcohol
235
1.00818
Phenylpropyl alcohol
241-2
o-Metho.\ybenzaldehyde
248
I.I2318
Anisaldehyde, m. 0°
143/ 15 mm.
0.831-2^
Lauryl alcohol, m. 24°
143-5/ 15 mm.
0.904
Pseudoionone
250
1.030^V-
Cinnamyl alcohol, m. 33°
262
Benzalacetone, m. 41°
174-81/10 mm.
Dibenzyl ketone
GROUP V. SUB-GROUPS 1, 2, 3
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
12°
124°
Paraldehyde
16
160
Cyclohexanol
16-8
105-7/Hmm.
Propiophenone
20
200
Acetophenone
24
143/15 mm.
Lauryl alcohol
28
198
Phorone
33
250
Cinnamyl alcohol
CLASSIFIED TABLES OF COMPOUNDS
217
GROUP V. SUB-GROUP 1, 2, 3— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
35°
218°
Terpineol
35
243
o-Methoxybenzaldehyde
37
263
Piperonal
39
Myristyl alcohol
40-1
a, 7-Dichloroacetone
41
262
Benzalacetone
42
212
Z-Menthol
45
259
Anisic alcohol
47
213
p-Chlorobenzaldehyde
48
305
Benzophenone
50
344
Cetyl alcohol
50
w-Bromoacetophenone
52-4
Phenyl p-tolyl ketone
55-6
o-Phthaldehyde
57
Benzalacetophenone
59
244
co-Chloroacetophenone
60
^-Naphthaldehyde
68
Toluquinone
70-1
2, 4-Dichlorobenzaldehyde
76
274
a-Bromo-d-camphor
77-8
Trichloro-ter/-butyl alcohol
78
Butyl chloral hydrate
80
285 d.
VaniUin
91-2
Di-p-tolyl ketone
95
347
Benzil
102
285
Terpin
112
Dibenzyhdineacetone
112-5 subl.
Metaldehyde
115
p-Hydroxybenzaldehyde
115-20 d.
^-Naphthoquinone
116
Benzoquinone
116
245-8
Terephthaldehyde
117
Terpin hydrate
125
a-Naphthoquinone
137
343
Benzoin
148
Z-Cholesterol
162
360
Triphenylcarbinol
167
Tribromo-^ert-butyl alcohol
171-2 subl.
Polyoxymethylene
173
Xanthone
176
205
d-Camphor
177
2-M ethyl anthraquinone
178
dZ-Camphor
218 QUALITATIVE ORGANIC ANALYSIS
GROUP V SUB-GROUPS 1, 2, S—dontinued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
180°
Populin (Glucoside)
185
Coniferin (Glucoside)
198
Camphorquinone
201
Salicin (Glucoside)
202
360°
Phenanthraquinone
204
212
d-Borneol
261
Acenaphthoquinone
273 (280)
380
Anthraquinone
290 subl.
Chloranil (Tetrachlorobenzoquinone)
GROUP V. SUB-GROUP 4
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
35°
0.719-1/
Ethyl ether
45
0.872-1/
Methylal
64
Dimethylacetal
69
0.7242 0
Diisopropyl ether
73-4
0.817Y
tt-Butyraldehyde
89
Ethylal
97-101
n-Amyl methyl ether \
101
Methyl orthoformate \
102
0.831-2/
Acetal
116
1.13812
a, a'-Dichloroethyl ether (s3Tn.)
116
1.203f
Epichlorohydria
124
0.994-2/
Paraldehyde
140
0.7692"
7i-Butyl ether
140
1.1742 3
a, /3-Dichloro diethyl ether
145
0.896-/
Ethyl orthoformate
154
0.988-2/
Anisole
157
1.02615
Monochloroacetal
167
0.981*
Benzyl methyl ether
170
M onobromoacetal
171
0.996"
o-Cresyl methyl ether
172
0.774f|
Isoamyl ether
172
0.979*
Phenetole
174-6
0.922
Cineol
175-8
/3, /3'-Dichloroothyl other
176
0.987"
p-Cresyl methyl ether
CLASSIFIED TABLES OF COMPOUNDS
GROUP V. SUB-GROUP 4:— Continued
219
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
177°
0.985*
m-Cresyl methyl ether
185
Benzyl ethyl ether
187-90
n-Amyl ether
195
o-Chloroanisole
200
p-Chloroanisole
206
1.086^5
Veratrole (1, 2-Dimethyoxy benzene)
m. 15°
208
o-Chlorophenetole
210
0.950
n-Butyl phenyl ether
212
p-Chlorophenetole, m. 20°
212
Benzyl isobutyl ether
213-6
Benzyl n-butyl ether
214
l.OSOf
Resorcinyl dimethyl ether
216
0.954"
Thymyl methyl ether
218
o-Bromoanisole
223
0.944°
n-Butyl o-cresyl ether
223
1.494»
p-Bromoanisole
224
o-Bromophenetole
229
p-Bromophenetole
232
1.09618
Safrole
232
0.98928
Anethole, m.21°
244
1.055^5
Eugenol methyl ether
246
1.1251*
Isosafrole
252
1.07320
Diphenyl ether, m. 28°
265
1.096^*
a-Naphthyl methyl ether
278
1.074
a-Naphthyl ethyl ether
282
/3-Naphthyl ethyl ether, m. 37°
178-9/11 mm.
/3-Naphthyl isoamyl ether, m. 26°
298
1.0361 «
Dibenzyl ether
220
QUALITATIVE ORGANIC ANALYSIS
GROUP V. SUB-GROUP 4
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
15°
207°
Veratrole
20
212
p-ChlorophenetoIe
21
232
Anethole
26
325
/3-Naphthyl isoamyl ether
28
252
Diphenyl ether
32
300
Apiole
37
282
/3-Naphthyl ethyl ether
43
246
s-Trichlorophenetole
55
212
Hydroquinone dimethyl ether
60
240
s-Trichloroanisole
72
274
/3-Naphthyl methyl ether
72
s-Tribromophenetole
87
s-Tribromoanisole
GROUP V. SUB-GROUP 5
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
72-5°
1.21811
Methyl chlorocarbonate
77
0.924f
Ethyl acetate
90
1.06922
Methyl carbonate, m. 0°
92
O.Ollf
Methyl isobutyrate
93
1.14415
Ethyl chlorocarbonate
98
Isobutj^l formate
98
0.914"
Ethyl propionate
101
0.899-1/
n-Propyl acetate
102
0.919f
Methyl n-butyrate
103
0.938
Allyl acetate
107
0.911«
n-Butyl formate
110
0.890f
Ethyl isobutyrate
111
0.892
sec-Butyl acetate
113
n-Propyl chlorocarbonate
116
0.892f
Isobutyl acetate
116
O.OOOf
Methyl isovalerate
120
0.899f
Ethyl n-butyrate
122
0.902^
n-Propyl propionate
123
0.894^
Isoamyl formate
125
0.8822 0
n-Butyl acetate
126
O.976-24P-
Ethyl carbonate
CLASSIFIED TABLES OF COMPOUNDS
GROUP V. SUB-GROUP 5— Continued
221
BOILING-POINT
SPECIFIC GRAVITY
NAMR OF COMPOUND
127-30°
0.9100
Methyl n-valerate
128
0.879°
Isopropyl n-butyrate
130
1 . 23.5f^
Methyl chloroacetate
134
0.885f
Ethyl isovalerate
137
0.892f
Isobutyl propionate
140-5
n-Butyl chlorocarbonate
142
0.876-1/
Isoamyl acetate
143
0.893"
n-Propyl n-butyrate
144 d.
Methyl bromoacetate
145
0.87620
Ethyl n-valerate
145
1 . 158-2/
Ethyl chloroacetate
145
1.178
/3-Chloroethyl acetate
145
'0.84713
Ethyl orthoformate
146
1.087^
Ethyl a-chloropropionate
147
0.875f
Isobutyl isobutyrate
150-2
1.03120
Ethyl lactate
157
0.888f
Isobutyl n-butyrate
158
1.2822/
Ethyl dichloroacetate
159
1.507|f
Ethyl bromoacetate
160
0.888f
Isoamyl propionate
162
1.39320
Ethyl a-bromopropionate
164-6
n-Propyl carbonate
165
0.888
n-Butyl n-butyrate
167
a-Angelica lactone, m. 18-19°
167
1.38320
Ethyl trichloroacetate, m. 141°
167
0.87320
Ethyl n-caproate
170
1.073|f
Methyl acetoacetate
171-6
Cyclohexylacetate
174-6
Methyl n-heptylate
177
1.020»o
Methyl methylacetoacetate
178
1.1071'^
Methyl methylmalonate
178
0.8820
Isoamyl butyrate
180
1.08115
n-Butyl chloroacetate
181
1.0242^0
Ethyl acetoacetate
181
1.16015
Methyl malonate
83-5/20 mm.
o-Cresyl acetate
186
1.07611
Ethyl oxalate
186
1 . 1280
Ethyleneglycoldiacetate
187
1.0098
Ethyl methylacetoacetate
190
0.9951*
Methyl ethylacetoacetate
67-70/8 mm.
Ethyl n-heptylate
191
Methyl levulinate
193
0.88718
Methyl caprylate
222
QUALITATIVE ORGANIC ANALYSIS
GROUP V. SUB-GROUP b— Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
194°
0.870"
Isoamyl isovalerate
196
1.02115
Ethyl methylmalonate
196
1.093f
Phenyl acetate
198
1.05411
Ethyl malonate
198
1.0^4-1/
Methyl benzoate
198
0.998^2
Ethyl ethylacetoacetate
90-1°/ 14 mm.
Isopropyl oxalate
202
1.01620
Ethyl levulinate
205
0.9242 0
Butyl carbonate
100-5/15 mm.
0.89520
Linalyl acetate
108-10/ 10 mm.
Ethyl n-butylmalonate
206 (215-6)
1.05716-5
Benzyl acetate
207
1.00511
Ethyl ethylmalonate
207
0.8870
Ethyl caprylate
210
0.885
sec-Octyl acetate
211
Phenyl propionate, m. 20°
213
1.0380
n-Propyl oxalate
213
1 -05411
Ethyl benzoate
217
1.04415
Ethyl succinate
218
1. 01711
Isopropyl benzoate
220
1.0441 «
Methyl phenylacetate
221
Bornyl acetate, in. 29°
223
Methyl caprate
110-12/ 10 mm.
Ethyl caprate
226
1.04611
Ethyl phenylacetate
227
0.985-2^
/-Menthyl acetate
129-30/8 mm.
Ethyl di-n-butylmalonate
228
Methyl o-methoxybenzoate
128-32/i8n]m.
n-Butyl phenylacetate
128-30/20 mm.
Isobutyl phenylacetate
133-4/20 mm.
Ethyl glutarate
230
1.03216
7i-Propyl benzoate
230
1.058if
Allyl benzoate
230
Ethyl diethylmalonate
127-9/8 mm.
Methyl laurate
233-5
1.42615
Ethyl bromomalonate
131-2/15 mm.
Ethyl adipate
235
|3, /3'-Dichloroethyl carbonate
235-7
1.137if
Ethyl salicylate
238
1.0331 6
Benzyl n-butyrate
241
1.00311
Isobutyl benzoate
243
1.0100
n-Butyl oxalate
CLASSIFIED TABLES OF COMPOUNDS
GROUP V. SUB-GROUP 5— Continued
223
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
245°
1.009"
Thymyl acetate
245
1.1501^
Methyl pheno.xyacetate
154-5/15 mm.
n-Butyl salicylate
246
1.016*
n-Propyl succinate
249
1.0002 0
n-Butyl benzoate
251
1.10417
Ethyl phenoxyacetate
260
1.159|f
Triacetin
262
1.004"
Isoamyl benzoate
262
0.96811
Isoamyl oxalate
263
1.042-%«-
Methyl cinnamate, ra. 36°
265
0.97415
Isobutyl succinate
265-70
7, 7'-Dichloropropyl carbonate
269
0.8671"
Ethyl laurate
269-70
1.119*
Ethyl anisate, m. 7°
185-6/50 mm.
rt-Butyl o-methoxybenzoate
270
1 -04511
Isoamyl salicylate
270
Methyl aconitate
271
1.0502 0
Ethyl cinnamate, m. 12°
196-8/15 mm.
/i-Butyl tartarate
275
1.130^0
Isopropyl tartarate
275
1.0741*
Ethyl aconitate
278 d.
Resorcinol diacetate
280
1.2062 0
Ethyl tartarate
282
1 . 189ff
Methyl phthalate
283
1.034i«
Ethyl benzylacetoacetate
285
1.03220
Glycerol tributyrate
288
Methyl sebacate, m. 38°
208/26 mm.
Benzyl salicylate
294
1 . 137-2/
Triethyl citrate
295
1.118-2/-
Ethyl phthalate
152-5/io mm.
Isopropyl phthalate
297
0.96113
Isoamyl succinate
300
1.07715
Ethyl benzylmalonate
307
o-Cresyl benzoate
307
0.9651 «
Ethyl sebacate
323
I.II418
Benzyl benzoate
204/5 2mm.
Tributyrin
243-6/18 mm.
1.093^
Ethyl dibenzylmalonate
d.
Trioleine
224
QUALITATIVE ORGANIC ANALYSIS'
GROUP V. SUB-GROUP 5
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
10-15°
Dioleine
12
271°
Ethyl cinnamate
13
250/40 mm.
Ethyl dibenzylmalonate
14
Cinnamyl cinnamate
15-20
Monoleine
16-17
Methyl myristate
20
211
Phenyl propionate
27-8
Methyl palmitate
29
221
Bornyl acetate
30
Benzyl cinnamate
33
Thymyl benzoate
36
263
Methyl cinnamate
37
254
Ethyl mandelate
37-8
Methyl stearate
42
Benzyl succinate
42
Benzyl phthalate
45
255
Methyl anisate
49-50
245/11 mm.
Triphenylphosphate
52
Methyl mandelate
^ 54
Trimyristin
'' 54
Z-Menthyl benzoate
^55
m-Cresyl benzoate
■? 60
Guaiacol benzoate
'', 61
Monostearine
'', 61
Dipalmitine
63
Monopalmitine
65
233-7
Tripalmitine
66
290
Ethyl trichlorolactate
67
Coumarin
68-9
Phenyl benzoate
70
Phenyl phthalate
71
Tristearine
71
205-7/15 mm.
p-Cresyl benzoate
72
Phenyl cinnamate
73
290
Glycol dibenzoate
73
PhthaUde
76
301
Distearine
78
284
Diphenyl carbonate
78-9
Methyl citrate
80
Benzyl oxalate
83
Guaiacol carbonate
86
Diglycolide
CLASSIFIED TABLES OF COMPOUNDS
GROUP V. SUB-GROUP 5— Continued
225
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
93''
^-Naphthyl salicylate
107
/3-Naphthyl benzoate
123
Hydroquinone diacetate
127
255°
Lactide
161
Pyrogallol triacetate
170
Santonin
223
Polyglycolide
GROUP V. SUB-GROUP 6
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
100°
1.028-2/
n-Butyryl chloride
115
0.989-2/ •
Isovaleryl chloride
191
0.978^^
7i-Butyric anhydride
197
1.212-^
Benzoyl chloride
102/17 mm.
1 . 168^
Phenyl acetyl chloride
213
1.2422 5
Citraconic anhydride
218
1.570^5
Benzoyl bromide
145/i4 mm.
Anisyl chloride, m. 26°
254
o-Methoxybenzoyl chloride
276
1.409-2^"
Phthalyl chloride, m. 14°
GROUP V. SUB-GROUP 6
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
26°
145°/ 14 mm.
Anisyl chloride
35-6
154/25 mm.
Cinnamoyl chloride
42
360
Benzoic anhydride
63
202
Maleic anhydride
85
Diphenylcarbamide chloride
103
Benzoyl peroxide
120
260
Succinic anhydride
130
Cinnamic anhydride
131
284
Phthalic anhydride
220
270
d-Camphoric anhydride
274
Naphthoic anhydride
226
QUALITATIVE ORGANIC ANALYSIS
GROUP V. SUB-GROUP 7
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OP COMPOUND
21°
3-M ethy Ibutene- 1
22-37
0.66ff
Amylene (techn.)
35-8
0.678"
Isoamylene
42
0.805-L9
Cyclopentadiene
58-9
0.690-2/
Diallyl
102-4
2-Methyl cyclohexene
102-4
3-Methyl cyclohexene
107-9
4-M ethyl cyclohexene
146
0.925
Styrene
155-60
0.85820
Pinene
160-70
0.8602 5
Terebene
167
0.814-2/
Menthene
176
0.846i»
Limonene
176
0.851i«
Sylvestrene
176-7
0.914if
Allyl benzene
180
1.04015
Indene
181
0.85416
Dipentene
212
Dihydronaphthalene
232
Safrole
244
1.035|i
Eugenyl methyl ether
246-8
Isosafrole
GROUP V. SUB-GROUP 7
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
15°
51
125
212°
160
306
Dihydronaphthalene
i-Camphene
Stilbene
CLASSIFIED TABLES OF COMPOUNDS
227
GROUP VI. SUB-GROUPS 1 and 2
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
30-1°
0.613V^
Isopentane
30-50
0. 62-. 6325
Petroleum ether (mixture)
36
0.645"
Pentane
50-70
0. 63-. 6625
Benzine (ligroin mixture)
68
0.660-V-
n-Hexane
70-100+
0. 70-. 7525
f Gasoline (mixture)
I Ligroin (mixture)
80
0.874-2/
Benzene, m. 5°
80
0.790-2/
Cyclohexane, m. 4°
100
0.769-2/
Methj^l cyclohexane
111
0.881|
Toluene
125
0.719f
n-Octane
135
0.876-V-
Ethyl benzene
137
0.866 V-
p-Xylene, m. 15°
139
0.871 J/
w-Xj'lene
142
0.890A
o-Xylene
150-300
0. 78-. 822 5
Kerosene (mixture)
153
0.875|
Cumene (Isopropyl benzene)
156-8
0.735-1/
Diisoamyl (decane)
158
0.870-V-
Propyl benzene
164
0.869J/
Mesitylene
167-9
0.796^5
p-Menthane
168
0.889*
Pseudocumene
175
0.85225
p-Cymene
180
1.040^5
Indene
182
0.860\"-
Diethyl benzene (0, to, and p)
240
1.00119
a-Methyl naphthalene
242
/3-Methyl naphthalene, m. 32°
261
1.0012/
Diphenylmethane, m. 26°
228
QUALITATIVE ORGANIC ANALYSIS
GROUP VI. SUB-GROUPS 1 and 2
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
15°
137°
p-Xylene
26-7
261
Diphenylmethane
32
242
/3-M ethyl naphthalene
52
284
Dibenzyl
70
254
Diphenyl
80
218
Naphthalene
92
359
Triphenylmethane
95 (103)
277
Acenaphthene
100
340
Phenanthrene
115
295
Fluorene
125
306
Stilbene
213
360
Anthracene
GROUP VI. SUB-GROUPS 3 and 4
Liquids
BOILING-POINT
specific GRAVITY
NAME OF COMPOUND
12-3°
0.9210
Ethyl chloride
36
0.8592 0
Isopropyl chloride
38
1.450^5
Ethyl bromide
42
1.378f
Methylene chloride
43
2.285^5
Methyl iodide
46
0.89220
n-Propyl chloride
46
0.9550
Allyl chloride
51
0.84715
tert-Butyl chloride
55
Acetylene dichloride
60
1.1802 2
Ethylidene chloride
60
1.31020
Isopropyl bromide
61
1 . 504 1 2
Chloroform
68
0.88015
Isobutyl chloride
70
2, 2-Dichloropropane
70
1.43615
Allyl bromide
71
1.35220
« -Propyl bromide
72
1.20215
lert-Buty\ bromide
72
1 .94311
Ethyl iodide
CLASSIFIED TABLES OF COMPOUNDS
GROUP VI. SUB-GROUPS 3 and 4^Continued
229
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
74°
1.325-2/
1, 1, 1-TrichIoroethane
77
0.88720
?i-Butyl chloride
78
1.591|f
Carbon tetrachloride
83
1.667i«
1-Chloro-l-bromoethane
83
1.2562 0
Ethylene chloride
86
0.8701"
tert-Amyl chloride
88
Trichloroethylene
89
1.703Y
Isopropyl iodide
91
1.27215
Isobutyl bromide
98
2.498^5
Methylene bromide
98 d.
1.571"
tert-Buty] iodide
98
1.1661*
Propylene chloride
100
1.27920
M-Butyl bromide
100
0.886*^
Isoamyl chloride
101
1.84812
Allyl iodide
102
1.743-2^0
7i-Propyl iodide
107
1.6891 »
s-Ethylene chlorobromide
108
1.194|f
tert-Amyl bromide
112
2.1001^
Ethylidene bromide
114
I.4571"
1, 2, 2-Trichloroethane
118
1.2062 2
Isoamyl bromide
119
1.59520
sec-Butyl iodide
120
1.60819
Isobutyl iodide
121
1.631^
Tetrachloroethylene
125
1.1891/
Trimethylene chloride
128
1.49719
tert-Amyl iodide
130
2.178^
Ethylene bromide, m. 9°
130
I.6I320
n-Butyl iodide
132
iii2ii_
. Chlorobenzene
Chlorocyclohexane
141-2
0.9815
142
1.93320
Propylene bromide
^
147
I.6I40
s-Tetrachloroethane
148
1.47320
Isoamyl iodide
151
2.90415
Bromoform, m. 9°
155
1.41715
Glycerol trichlorhydrin
157
1.49120
Bromobenzene
159
1.081-2/
o-Chlorotoluene
161
1.693i/
Pentachloroethane
162
1.072-2/
TO-Chlorotoluene
162
1.0702 0
p-Chloro toluene, m. 7°
165
1.820-2/
1, 2-Dibromobutane
165
1.9731^
Trimethylene bromide
230 QUALITATIVE ORGANIC ANALYSIS
GROUP VI. SUB-GROUPS 3 and A— Continued
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
eOVlOmm.
Bromocyclohexane
172
1.307«
TO-Dichlorobenzene
174-8
1.133^8
n-Heptylbromide
179
1.114*
Benzyl chloride
179
1.328<'
o-Dichlorobenzene
180 d.
3.285^5
Methylene iodide, m. 4°
181
1.422-2/
o-Bromotoluene
183
1.410^
m-BromotoIuene
185
1.354\4-
p-Bromotoluene, m. 28°
188
1.83220
lodobenzene
195
1.2462 0
2, 4-Dichlorotoluene
198
1.438-V-
Benzyl bromide
200 d.
2.971Y
s-Tetrabromoethane
204
1.6982 0
m-Iodotoluene
211
1.69720
o-Iodotoluene
211
p-Iodotoluene
212
1.295i«
Benzal chloride
213
1.380^*
Benzotrichloride
214
o-Chlorobenzyl chloride
214
p-Chlorobenzyl chloride, m. 29°
110-15/15 mm.
o-Bromobenzyl chloride
219
1.955Y
m-Dibromobenzene
219
2.4362 3
Glycerol tribromohydrin, m. 16°
220 d.
1.3925
co-Bromostyrene
224
I.9771'
o-Dibromobenzene
175-80/45 mm.
Lauryl bromide
263
1.1942/
a-Chloronaphthalene
279
1.4881'
<x-Bromonaphthalene, m. 4°
200/30 mm.
Diphenyldichloromethane
CLASSIFIED TABLES OF COMPOUNDS
231
GROUP VI. SUB-GROUPS 3 and 4
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
16°
219°
Glycerol tribromohydrin
28
185
p-Bromotoluene
35
211
p-Iodo toluene
45
184/20 mm.
Diphenylbromomethane
48
p-Chlorobenzyl bromide
51
236
p-Bromobenzyl chloride
53
172
p-Dichlorobenzene
56
266
/3-Chloronaphthalene
59
281
/3-Bromonaphthalene
67
1, 2-DibromonaphthaIene
81-2
Ethylene iodide
89
219
p-Dibromobenzene
92
189 d.
Carbon tetrabromide
106-9
Triphenylchloromethane
116
Iodoform
128
p-Diiodobenzene
129
210
Pinene hydrochloride
157
Bornyl chloride
169-70
s-Tetramethyl dibromoethane
180
1, 2, 4, 5-Tetrabromobenzene
182
Naphthalene tetrachloride
187
Hexachloroethane
229
326
Hexachlorobenzene
232
QUALITATIVE ORGANIC ANALYSIS
GROUP VII. SUB-GROUP 1
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
113°
1.692
Chloropicrin
126
1.650-1/
Tetranitromethane, m. 13°
110/40 mm.
1.02520
1-Nitro-l-methylcyclohexane
101-2/10 mm.
2-Nitro-p-xylene
209
1.203-Y-
Nitrobenzene, m. 5°
224
1.16811
o-Nitrotoluene
231
1.1682 2
m-Nitrotoluene, m. 16°
238
1.126^'
4-Nitro-m-.\ylene, m. 2°
126-8/10 mm.
2-Nitrocymene
150-1/iOmm.
Methyl-o-nitrobenzoate
265
1.2682 0
o-Nitroanisole, m. 9°
268
o-Nitrophenetole
275-8 d.
m-Nitrobenzoyl chloride, m. 35°
I75-8O/3 ram.
rra-Nitrobenzyl alcohol, m. 27°
GROUP VII. SUB-GROUP 1
Solids
MELTING-POINT
BOILING POINT
NAME OF COMPOUND
- 13*
126°
Tetranitromethane
16
231
TO-Nitrotoluene
27
I75-8O/3 mm.
TO-Nitrobenzyl alcohol
32
246
o-Chloronitrobenzene
33-5
275-8 d.
w-Nitrobenzoyl chloride
43
261
o-Bromonitrobenzene
44
235
w-Chloronitrobenzene
44
150/20 mm.
o-Nitrobenzaldehyde
44
225
Nitromesitylene
45
173/30 mm.
7tt-Nitrobenzyl chloride
47
296
Ethyl m-nitrobenzoate
48
o-Nitrobenzyl chloride
49
o-Nitroiodobenzene
50
315 d.
Chloro-2, 4-dinitrobenzene
54
258
p-Nitroanisole
54
238
p-Nitrotoluene
54
266
2, 5-Dichloronitrobenzene
CLASSIFIED TABLES OF COMPOUNDS
GROUP VII. SUB-GROUP 1— Continued
233
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
56°
256°
OT-Bromonitrobenzene
58
?rt-Nitrobenzaldehyde
60
304
a-Nitronaphthalene
60
283
p-Nitrophenetole
64
s-Trinitroanisole
65
TO-Nitroethylaniline
65
m-Nitrobenzal chloride
66
2, 6-Dinitrotoluene
70
2, 4-Dinitrotoluene
71
p-Nitrobenzyl chloride
72
Bromo- 2, 4-dinitrobenzene
74
o-Nitrobenzyl alcohol
75
202/100 mm.
p-Nitrobenzoyl chloride
~78'
s-Trinitrophenetole
78
Methyl ?rt-nitrobenzoate
78
/3-Nitronaphthalene
80
l-Nitro-l-methylcyclohexane
>82
s-Trinitrotoluene
83
242
p-Chloronitrobenzene
83
Picryl chloride
90
302
TO-Dinitrobenzene
92
o-NitroacetanUide
92
3, 5-Dinitrotoluene
93
p-Nitrobenzyl alcohol
93
4, 6-Dinitro-m-xylene
94
3-Ni tro-4-acetaminotoluene
96
Methyl />nitrobenzoate
96
Dinitrohydroquinone diacetate
99
p-Nitrobenzyl bromide
106
p-Nitrobenzaldehyde
116
3-Nitro-4-aminotoluene
116
p-Nitrophenylacetonitrile
118
p-Nitroethylacetanilide
119
2, 4, 6-Trinitrobenzaldehyde
121
s-Trinitrobenzene
126
255
p-Bromonitrobenzene
130-2
4-Nitrodiphenylamine
142
wi-Nitrobenzamide
149-51
p-Nitromethylaniline
153
m-Nitrobenzanilide
153
p-Nitromethylacetanilide
234
QUALITATIVE ORGANIC ANALYSIS
GROUP VII. SUB-GROUP 1— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
154°
m-Nitroacetanilide
171
p-Nitroiodobenzene
176
o-Nitrobenzamide
183
2, 6-Dichloro-4-nitroaniline
183
3, 5-Dinitrobenzamide
201
p-Nitrobenzamide
207
p-Nitroacetanilide
210
1, 5-Dinitronaphthalene
240-7
Nitroguanidine
GROUP VII. SUB-GROUP 2
Solids
MELTING-POINT
BOILING-POIxNT
NAME OF COMPOUND
273-57718 mm.
Acetyl n-butylaniline
38°
298
A^-Ethyl phenacetin
41
295-300
A^-M ethyl phenacetin
46
284
Formanilide
48
360 d.
Benzoyl piperidine
50
266
Acetyl n-propylaniline
51
237 d.
A^-Phenyl urethane
53-4
n-Butyl carbamate
54
300
Benzalaniline
54
258
A'^-Ethyl acetanilide
54
310
Diphenylamine
54-6
Acetyl methyl-o-toluidine
60
Isoamyl carbonate
60
Ethyl hippurate
62
A-Phenyl-a-naphthylamine
62-4
Isoamyl carbamate
65
303
Acetyl m-toluidine
66
Ethyl oxanilate
70
Ethyl-|3-naphthyl carbamate
71
o-Nitroaniline
72
Diphenyl urethane
73
Formyl diphenylamine
77
262
s-Trichloroaniline
79
Ethyl a-naphthyl carbamate
79
330
Di-p-tolylamine
CLASSIFIED TABLES OF COMPOUNDS 235
GROUP VII. SUB-GROUP 2— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
79°
Diethylcarbanilide
83
283°
Acetyl methyl-p-toluidine
85
Acetoacetanilide
86
220 d.
Benzyl carbamate
88
?i-Butyl oxamate
90
n-Butyranilide
92
o-Nitroacetanilide
94
3-Nitro-4-acetylaminotoluene
97-8
Diacetyl-iV-methyl-p-aminophenol
98
234
Dichloroacetamide
101
Acetyl diphenylamine
102
260
Methyl acetanilide
103
Propionanilide
^109
Isovaleranilide
110
Hydrobenzamide
110-11
296
Acetyl o-toluidine
. 114
305
Acetanilide
114
Ethyl oxamate
116
Diethyl bromoacetyl carbamide
116
3-Nitro-4-aminotoluene
117
3-Bromo-4-acetylaminotoluene
117
a-Phenylacetanilide
117
250 d.
Furfuramide
118
p-Nitro-A'^-ethylacetanilide
119 ,
300
s-Tribromoaniline
T20
350
Dimethylcarbanilide
127
347
Triphenylamine
127
Acetyl p-anisidine
128
s-Acetyl phenylhydrazine
128
290
Benzamide
128-30
Piperine
129
4-Acetamino-m-xylene
132
Aceto-/3-naphthylamine
135
Phenacetiu
138
2, 6-Dinitroaniline
142
m-Nitrobenzamide
142
Cinnamamide
142
Benzo-o-toluidine
145
a-Bromo-isovaleryl urea
147
Benzyl carbamide
147
Phenyl carbamide
150
Cinnamanihde
236 QUALITATIVE ORGANIC ANALYSIS
GROUP VII. SUB-GROUP 2— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
151°
Succinanil
153
307°
Acetyl-p-toluidine
153
m-Nitrobenzanilide
154
m-Nitroacetanilide
154
281-4 d.
a-Phenylacetamide
155
o-Bromobenzamide
155
?n-Bromobenzainide
158
232
p-Benzot oluidide
159
Aceto-a-naphthylamine
159-60
p-Toluamide
160
Benzanilide
161
Benzoyl-a-naphthylamine
166
Phenyl isocyanate
167
p-BromoacetaniUde
167
Dibenzylcarbamide
168
Benzoyl phenylhj'drazine
168-9
p-Acetylaminophenol
173^
p-Phenetyl urea
176
o-Nitrobenzamide
179
;>Chloroacetanilide
180
2, 4-DinitroaniIine
181-2
p-Iodoacet anilide
183
3, 5-Dimtrobenzamide
183
o-Iodobenzamide
185
Diacetyl-o-phenylenediamine
186
r«-Iodobenzamide
188
Picramide
189
p-Bromobenzamide
190
Biuret
191
Diacetyl-m-phenylenediamine
201
p-Nit robenzamide
203-5
Phthalanil
207
p-Nitroacetanilide
217
p-Iodobenzamide
219 d.
Phthalamide
226
Suooinanilide
238
260 subl.
Carbanilide
238-40
A'^-Acetyl-p-methylaminophenol
242-3
Succinamide
245-7
Oxanilide
300+
Diacetyl-p-phenylenediamine
subl.
Oxamide
CLASSIFIED TABLES OF COMPOUNDS
237
GROUP VII. SUB-GROUP 3
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
107-8^
Isobutyronitrile
118
0.79512
7i-Butyronitrile
141
0.816"
n-Valeronitrile
155
0.8062 0
Isocapronitrile
170 d.
1.124
Mandelonitrile
191
1.0002 5
Benzonitrile
205
0.99815
o-Toluonitrile
207
1.066
Ethyl cyanoacetate
212
0.98414
7w-Toluonitrile
233
1.017-V^
Phenj^l aoetonitrile
254
1.037"
Cinnamonitrile
286
0.99515
Trimethylene cyanide
GROUP VII. SUB-GROUP 3
Soli
DS
MELTING POINT
BOILING-POINT
NAME OF COMPOUND
35°
299°
a-Naphthonitrile
38
217
p-Toluonitrile
52
265-7 d.
Succinonitrile
66
306
/3-NaphthonitriIe
129
Methyleneamine acetonitrile
GROUP VII. SUB-GROUP 4
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
17°
0.90015
Ethyl nitrite
44
0.93520
n-Propyl nitrite
65
1.21715
Methyl nitrate
67
0.888*
Isobutyl nitrite
75
0.9110
n-Butyl nitrite
87
1.11615
Ethyl nitrate
99
0.88015
Isoamyl nitrite
110
1.06315
n-Propyl nitrate
123
1.02115
Isobutyl nitrate
130-1
0.967-V-
Pyrrol
136
1.0480
«-Butyl nitrate
147
1.000^
Isoamyl nitrate
166
0.97715
Phenyl isocyanate
230 d.
Camphorphenylhydrazone
238
QUALITATIVE ORGANIC ANALYSIS
GROUP VII. SUB-GROUP 4
Solids
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
36°
Azoxy benzene
42
165°/ 90 mm.
Acetone phenylhydrazone
55
o-Azotoluene
59
o-Azoxytoluene
63
Acetaldehyde phenylhydrazine
66
Diphenyl nitrosoamine
68
Nitrosobenzene
68
296
Azobenzene
70
p-Azoxytoluene
93
Benzalazine
96
Diazoaminobenzene
103-5
Acetophenone phenylhydrazone
127
287/205 mm.
l-Phenyl-3-methyl pyrazolon-5
130
Hydrazobenzene
131
o-Azophenetole
137
Benzophenone phenylhydrazone
144
p-Nitrosodiphenylamine
144
p-Azotoluene
154
pp'-Dichloroazoxybenzene
156
Benzaldehyde phenylhydrazone
160
p-Azophenetole
161
o-Hydrazotoluene
GROUP VII. SUB-GROUPS 5 and 6
Liquids
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
36°
0.839-2/
Ethyl mercaptan
37
0.84521
Methyl sulfide
46
1.292°
Carbon disulfide
83-4
1.06ff
Thiophene
92-3
0.837-242.
Ethyl sulfide
97
0.858"
n-Butyl mercaptan
121
1.046-^/
Methyl sulfite
133
1.0692*
Methyl thiocyanate
140
0.887^
Allyl sulfide
143
1.00724
Ethyl thiocyanate
CLASSIFIED TABLES OF COMPOUNDS
GROUP VII. SUB-GROUPS 5 and &— Continued
239
BOILING-POINT
SPECIFIC GRAVITY
NAME OF COMPOUND
150°
1.0062*
Allyl isothiocyanate
153
0.993-2^
Ethyl disulfide
161
1.1060
Ethyl sulfite
184-7
0.852
n-Butyl sulfide
188
1.33315
Dimethyl sulfate
194
1.0582 0
Benzyl mercaptan
208
1.18419
Diethyl sulfate
221
1.12923
Phenyl isothiocyanate
231
1.15517
Phenyl thiocyanate
251 d.
1 -38411
Benzenesulfonyl chloride, m. 14°
d.
o-Toluenesulfonyl chloride
292
1.118if
Diphenyl sulfide
GROUP VII.
SUB-GROUPS 5 and 6
Solids
MELTING-POINT
BOILING-POINT
NAME OP COMPOUND
14°
251° d.
Benzenesulfonyl chloride
28
Methyl p-toluenesulfonate
32
173/15 nun.
Ethj'l p-toluenesulfonate
35
Phenyl benzenesulfonate
41
230-5 d.
Benzyl thiocyanate
43
n-Butyl sulfone
49
Benzyl sulfide
52
Phenyl o-toluenesulfonate
52-3
o-Cresyl p-toluenesulfonate
60
310
Phenyl disulfide
63
Benzene-m-disulfonj'l chloride
68
194/13 mm.
a-Naphthalenesulfonyl chloride
69
145/15 mm.
p-Toluenesulfonyl chloride
70
Phenyl sulfo.xide
71
Benzyl disulfide
75
p-Bromobenzenesulfonyl chloride
76
Trional
76
201/13 mm.
/3-Naphthalenesulfonyl chloride
80
Benzenesulfonylmethylaniline
87
p-Toluenesulfonylethylaniline
94
p-ToluenesulfonylmethylaniUne
94
Phenyl p-toluenesulfoate
94-5
p-Toluenesulfonylmethylaniline
98
Allyl phenyl thiocarbamide
101
246
a-Trithioacetaldehyde
240 QUALITATIVE ORGANIC ANALYSIS
GROUP VII. SUB-GROUPS 5 and Q— Continued
MELTING-POINT
BOILING-POINT
NAME OF COMPOUND
114°
284°
Thiophthalic anhydride
124
Benzenesulfonyldiphenylamine
125
300 d.
Sulfonal
125-6
245-8
/3-Trithioacetaldehyde
128
377
Diphenyl sulfone
128
Dibenzenesulfonylaniline
133
Benzyl sulfoxide
150
Dibenzyl sulfone
153
Thiocarbanilide
154
Phenyl thiocarbamide
216 subl.
Trithioformaldehyde
SOLUBILITY TABLE
SOLUBLE IN WATER-
-GROUPS I AND 11
INSOLUBLE IN
WATER— GROUPS III, IV, V. VI, and VII
INDIFFERENT COMPOUNDS
SOLUBLE
SOLUBLE
OF C, H, AND C, H, O
1
INDIFFERENT
SOLUBLE IN ETHER
INSOLUBLE IN ETHER
IN DILUTE
IN DILUTE
SOLUBLE IN
IW SOLUBLE
COMPOUNDS
HCI
KOH
COLD CONC.
HjS04
IN COLD
H2S04
CONTAINING N or S*
I
II
III .
IV
V
VI
VII
1. Alcohols (low mol. wt.)
1.
Polybasic acids, hy-
droxy acids, etc.
1. Primary
1
Acids
1. Alcohols
1. Saturated
aliphatic
hydrocar-
bons
1. Nitro compounds (tertiary)
2. Aldehydes (low mol.)
2
Poly hydroxy alcohols.
2. Secondary
2
Phenols
2. Aldehydes
2. Aromatic
2. Amides and negatively sub-
wt.)
sugars, and certain
derivatives
amines
hydrocar-
bons
stituted amines
3. Ketones (low mol. wt.)
3.
Some amides, amino
3. Tertiary
3
Some am-
3. Ketones and
3. Halogen
3. Nitriles
acids, amines, etc.
amines
ides, imides,
etc.
quinones
derivatives
of VI,
4. Other neutral oxygen-
4
Many sulfonic acids
4. Hydra-
4
A few nitro
4. Ethers and
4. Halogen
4. Nitrites, nitrates, azo, and
ated compounds
and other sulfur com-
pounds
zines
compounds
and oidmes
acetals
derivatives
of VI2
hydrazo compounds, etc.
5. Acids (mostly low mol.
.5
Many salts
5. Miscella-
5.
Some thio-
5. Esters and
5. Sulfones, sulfonyl deriva-
wt.)
neous
phenols, sul-
fonic and
sulfinio acid
lactones
tives of secondary amines
6. A few anhydrides
G
Miscellaneous
6
A few enols
6. Anhydrides
6. Mercaptans, sulfides, sul-
fates, etc.
7. A few esters, phenols.
7
Miscella-
7. Unsaturated
7. Miscellaneous
etc.
neous
hydrocar-
bons
8. Amines (mostly low
mol. wt.)
9. Neutral nitrogen com-
pounds
10. Miscellaneous
* Halogen compounds j
Simijarly certain nitrogen
ire not listed separately but are met in each one of the seven groups in accordance with their solubility behavior,
and sulfur compounds will fall in Groups I, II, III, and IV. See pp. 187, ISS.
INDEX
Acenaphthene, 228
Acenaphthoquinone, 218
Acetal, 190, 218
Acetaldehyde, 189
ammonia, 198
phenylhydrazine, 238
Acetaldoxime,a-, 195
Acetamide, 195, 198
Acetamino-m-xylene,4-, 235
Acetanilide, 235
Acetic acid, 6, 192
anhydride, 192
Acetoacetanilide, 235
Aceto-a-naphthylamine, 236
Aceto-/3-naphthylamine, 235
Acetone, 189
cyanohydrin, 194
phenylhydrazone, 238
tests, 154
Acetonitrile, 194
Acetophenone, 216, 217
oxime, 212
phenylhydrazone, 238
Acetoxime, 195
Acetyl-acetone, 190
-m-aminobenzoic acid, 208
-p-aminobenzoic acid, 208
-aminophenol,p-, 236
-o-aminophenol, N-, 211
-p-aminophenol,N-, 211
-p-anisidine, 235
-anthraniUc acid, 207
bromide, 191
-n-butylaniUne, 234
chloride, 191
Acetyl diphenylamine, 235
methyl urea,s-, 198
-p-methylaminophenol,N-, 211, 236
methyl-o-toluidine, 234
methyl-p-toluidine, 235
-phenylglycine, 207, 208
phenylhydrazine,s-, 235
piperidine, 194
n-propylaniline, 234
-salicylic acid, 207
-m-toluidine, 234
-o-toluidine, 235
-p-toluidine, 236
urea, 198
Acetylene-dicarboxylic acid, 193
dichloride, 228
Acid phthalates, 152
Acidic compounds, 54
groups, 22
nitrogen, 67
Acids, aliphatic, 6
solubility of, 26
Aconitic acid, 196
Acridine, 203
Acrolein, 189
Acrylic acid, 192
Acyl halides, 41, 135
Acylation of amines, 59
Adipic acid, 207
Alanine, 87, 198
Alcohol test, 136
Alcohols, 48, 51
solubility of, 24
Aldehydes, 42, 43, 46, 142
solubility of, 26
Alizarin, 211
Alkaloids, 94
242
INDEX
Alloxan, 198
AUyl acetate, 190, 220
alcohol, 189
-amine, 193
benzene, 226
benzoate, 222
bromide, 228
chloride, 228
formate, 189
iodide, 229
isothiocyanate, 78, 239
phenyl thiocarbamide, 239
sulfide, 238
thiocarbamide, 195
Amide formation, 157
test, 138
Amides, 71
Amine, derivatives, 160-1
tests, 59, 144
Amino-acetanilide,;;,- 203
-acetophenone,p-, 203
acids, aliphatic, 87, 102
acids, aromatic, 92
-anthraquinone, 1-, 204
-anthraquinone,2-, 204
-azobenzene,p-, 203
-5-azotoluene,2-, 203
-benzenesulfonic acid,p-, 204
-benzoic acid,m-, 204, 207
-benzoic acid,p,- 204, 208
-benzoic acids, 18
-n-caproic acid,dl-,a-, 204, 207
-caprylic acid,dl-,a-, 204, 209
-cinnamic acid,o-, 207
-cinnamic acid,p-, 207
-o-cresol,5-, 204
-ethyl alcohol,/3-, 197
-2-hydroxytoluene,5-, 211
-isobutyric acid,a-, 198
-naphthalene sulfonic acid, 213
-phenol,m-, 194, 198, 203, 211
-phenol,o-, 194, 198, 204, 211
-phenol,p-, 204, 211
-phenylacetic acid,rW-,a-, 208
-salicylic acid,5-, 204, 209
-n-valeric acid,dl-,a-, 204, 209
-TO-xylene,4-, 200
Amino-p-xylene, 200, 201
Ammoniacal AgNOs, 142
Amygdalin, 197
Amyl alcohol, n-, 24, 215
alcohol,se'c-, 190, 215
alcohoMerf-, 190, 215
-amine, n-, 193
bromide, <erf-, 229
chloride, <er<-, 229
ether,n-, 219
iodide,tert-, 229
methyl ether,n-, 218
Amylene, 226
Analysis: acids, 138
alkoxyl group, 72
amine group, 174
Beilstein test, 124
carbonyl group, 171
carboxyl group, 172
Carius method, 124
elements, 121
ester group, 140, 172
halogen estimation, 168
test, 123
hydroxyl group, 171
ignition test, 132
Kjeldahl method, 167
metals, 169
nitrogen test, 123
saponification, 172
sodium decomposition, 122
sulfur test, 123
unsaturation, 170
Zeisel method, 172
Anethole, 219, 220
Angelica lactone,a-, 221
lactone,/3-, 190
Anhydrides, 47
Aniline, 200
Anisaldehyde, 216
Anisic acid, 207
alcohol, 217
Anisidine,o-, 200
,p-, 202
Anisole, 218
Anisyl chloride, 225
Anthra-cene, 228
quinone, 218
Anthra quinonylhydrazine, 205
INDEX
243
AnthranUic acid, 203, 207
Antipyrine, 195, 198
Apiole, 220
Arabinose,/-, 197
Arbutin, 211
Aromatic hydrocarbons, 35, 134, 135
Aryl hydrazones, 153
Asparagine,d-, 198, 204, 208
,1-, 198, 204, 208
Aspartic acid,?-, 198
Atropine, 95, 203
Aurin, 211
Azo-benzene, 238
compounds, 71-2,
-phenetole,o-, 238
-phenetole,p-, 238
-phenol,o-, 211
-phenol,p,- 211
-toluene,o-, 238
-toluene, p-, 238
Azoxy-benzene, 238
compounds, 71-2
-toluene,o-, 238
-toIuene,p,- 238
B
Barbituric acid, 198
Basic groups, 19, 59
Beilstein test, 124
Benzal-acetone, 216, 217
-acetophenone, 217
-amino-o-cresol,5-, 211
-aminophenol,p-, 211
-aniline, 234
-azine, 238
chloride, 230
-doxime,a-, 212
Benzaldehyde, 215
phenylhydrazone, 238
Benzamide, 235
Benzamidine, 202
Benzanilide, 236
Benzene, 227
-azo-o-cresol, 211
-m-disulfonylchloride, 239
-sulfinic acid, 195, 213
Benzene-sulfcnamide, 213
-sulfonic acid, anhydr., 199
-sulfonic acid, hydr., 199
-sulfonyl benzylamine, 213
-sulfonyl chloride test, 144, 239
-sulfonyl TO-nitraniline, 213
-sulfonyl o-nitraniline, 213
-sulfonyl p-nitraniline, 213
-sulfonyl TO-toluidme, 213
-sulfonyl o-toluidine, 213
-sulfonyl p-toluidine, 213
-sulfonylaniline, 213
-sulfonylchloraniline, 213
-sulfonyldiphenylamine, 240
-sulfonylmethylaniline, 239
Benzidine, 203
rearrangement, 73
BenzU, 217
dioxime,a-, 212
Benzilic acid, 207
Benzine, 227
Benzoic acid, 207
anhydride, 206, 225
sulfimide, o-, 213
Benzoin, 217
Benzo-nitrile, 237
-phenone, 217
-phenone oxime, 212
-phenone phenylhydrazone, 238
-quinone, 191, 217
-o-toluidide, 235
-p-toluidide, 236
-trichloride, 230
Benzoyl-acetone, 214
alanine,riZ-, 207
bromide, 225
carbinol, 191
chloride, 225
-a-naphthylamine, 236
peroxide, 225
phenylhydrazine, 236
piperidine, 234
Benzyl acetate, 222
alcohol, 216
-amine, 26, 194
-aniline, 201
benzoate, 223
bromide, 230
244
INDEX
Benzyl n-butyl ether, 219
TC-butyrate, 222
carbamate, 235
carbamide, 235
chloride, 149, 230
cinnamate, 224
disulfide, 239
ethyl ether, 219
ethylaniline, 201
isobutyl ether, 219
malonic acid, 193, 207
mercaptan, 239
methyl ether, 219
methylaniline, 201
oxalate, 224
phthalate, 224
salicylate, 223
succinate, 224
sulfide, 239
sulfoxide, 240
thiocyanate, 239
Retain, 198
Biuret, 198, 236
Boiling-points, 117
Borneol,d-, 218
Bornyl acetate, 222, 224
chloride, 231
Bromal, 190
alcoholate, 191
hydrate, 191
Bromine-water test, 137
Bromo-acetanilide,p-, 236
-acetic acid, 192
-acetophenone, CO-, 217
-acetyl bromide, 192
-acetyl chloride, 192
-4-acetylaminotoluene,3-, 235
-4-arainotolucne,3-, 201
-aniline,TO-, 201
-aniline,o-, 201
-aniline, 7^-, 202
-anisole,o-, 219
-anisole,p-, 219
-benzamide,m-, 236
-benzamide,o-, 236
benzamide,p-, 236
-benzene, 229
-benzenesulfonyl chloride, p-, 239
Bromo-benzolc acid,7/i-, 18, 207
-benzoic acid,o-, 18, 207
-benzoic acid,p-, 18, 208
-benzyl chloride,o-, 230
-benzyl chloride, ;>, 231
-n-butyric acid,a-, 18, 206
-rf-camphor,a-, 217
-cyclohexane, 230
-2, 4-dinitrobenzene, 233 -
-form, 229
-hydroquinone, 193, 210
-isovaleryl urea,a- 235
-naphthalene, a-, 230
-naphthalene,/^-, 231
-nitrobenzene, m-, 18, 233
-nitrobenzene,o-, 18, 232
-nitrobenzene, p-, 18, 233
-phenetole,o-, 219
-phenetole,p- 219
-phenol, m-, 209, 210
-phenol,o-, 209
-phenol, p-, 210
-phenylhydrazine,p-,205
-propionic acid,a-, 192, 206
-propionic acid,^-, 192
-styrene,co-, 230
-toluene, /«-, 230
-toluene,o-, 230
-toluene,p,- 230, 231
-n-valeric acid,a-, 206
Brucine, 204
Butyl acetate, n-, 220
acetate,sec-, 220
alcohol, n-, 24, 50, 190
alcohol,sec-, 189
sdcoho\,tert-, 189, 191
-amine,n-, 193
-amine,sec-, 193
-aniline, n-, 200
benzoate,n-, 223
bromide, n-, 229
bromide,/er<-, 228
n-butyrate,n-, 221
carbamate,7i-, 234
carbonate,n-, 216
chloralhydrate, 217
chloride,n-, 229
chloride,<er<-, 226
INDEX
245
Butyl chloroacetate,n-, 221
chlorocarbonate,n-, 221
o-cresyl ether, n-, 219
ether,n-, 218
formate,/!-, 220
iodide,n-, 229
iodide,sec-, 229
iodide,tert-, 229
mercaptan,7i-, 238
o-methoxybenzoate,n-, 223
methyl carbinol,n-, 215
nitrate,n-, 237
nitrite,n-, 237
oxalate,/!-, 222
oxamate,ri-, 235
phenylacetate,rt-, 222
phenyl ether,n-, 219
salicylate, n-, 223
sulfide,/!-, 239
sulfone,n-, 239
tartarate,n-, 223
Butyr-aldehyde,n-, 189, 218
-amide,n-, 195, 198
-anilide,/!-, 235
Butyric acid,n-, 6, 192
anhydride,/!-, 206, 225
Butyronitrile,/!-, 237
Butyryl chloride,/!-, 191, 225
Caffeine, 93, 198, 204
Camphene,^, 226
Camphor,^-, 218
,dl-, 218
oxime,d-, 212
-phenylhydrazone, 237
sulfonic acid, 199
sulfonic acid,c?-, 199
Camphoric acid,d-, 208
anhydride, d-, 225
Camphorquinone, 218
Capric acid, 206
Caproic acid,n-, 206
Caprjdic acid,/!-, 206
Carbamide, 198
Carbanilide, 236
Carbohydrates, 82, 155
Carbon disulfide, 76, 238
tetrabromide, 231
tetrachloride, 229
Carbonyl group, 171
Carboxyl group, 57, 172
Carius method, 124
Carvacrol, 209
Catechol, 193
Cetyl alcohol, 217
Characterization of compounds, 2
Chloral, 101, 189
alcoholate, 191
-formamide, 195
hydrate, 191
Chloranil, 218
Chloro-acetanilide,/)-, 236
-acetic acid, 192
-acetone, 190
-acetophenone, o)-, 217
-acetyl bromide, 192
-acetyl chloride, 191
-aniline,//!-, 200
-aniline,o-, 200
-aniline, p-, 202
-anisole,o-, 219
-anisole,p-, 219
-benzaldehyde,//!-, 216
-benzaldehyde,o-, 216
-benzaldehyde, p-, 217
-benzene, 229
-benzoic acid,r/!-, 207
-benzoic acid,o-, 207
-benzoic acid,p-, 208
-benzoic acids, 18
-benzyl bromide,p-, 231
-benzyl chloride,o-, 230
-benzyl chloride, p-, 230
-l-bromoethane,l-, 229
-/>!-cresol,6-, 210
-cyclohexane, 229
-2, 4-dinitrobenzene, 232
-ethyl acetate, /3-, 221
-ethyl ether, 191
-form, 228
-hydroquinone, 193
-methyl ether, 191
-methylethyl ether, 191
246
INDEX
Chloro-naphthalene,a-, 230
-naphthalene,-^, 230
-nitrobenzene, 18
-nitrobenzene,™-, 232
-nitrobenzene,o-, 232
-nitrobenzene, p-, 233
-phenetole,o-, 219
-phenetole,p-, 219, 220
-phenol,m-, 209, 210
-phenol,o-, 209
-phenol, p-, 210
-picrin, 232
-propionic acid,a, 192
-propionic acid,i3, 192
-toluene,m-, 229
-toluene,o-, 229
-toluene, p-, 229
-toluenes, 149
Cholesterol, 218
Choline, 198
Cinchonidine, 204
Cinchonine, 204
Cineol, 219
Cinnam-aldehyde, 216
-amide, 235
Cinnamic acid, 207
anhydride, 225
Cinnamonitrile, 237
Cinnamoyl chloride, 225
Cinnamyl alcohol, 216, 217
cinnamate, 224
Citraconic acid, 196
anhydride, 225
Citral, 216
Citric acid, 196
Citronellal, 216
Classification reactions :
Acetylene derivatives, 34
Acidic compounds, 54
Acidic nitrogen, 67
Acids, 55, 57 "^
Acyl halides, 41, 135
Acylation of amines, 59
Alcohols, 48, 51, 136
Aldehydes, 42, 43, 46
Aliphatic hydrocarbons, 34, 134
Amides, 71, 145, 146
Amines, 61, 144
Classification reactions:
Ammoniacal AgNOs, 142
Anhydrides, 47
Aromatic hydrocarbons, 35, 134,
135
Azo compounds, 71, 72
Azoxy compounds, 71, 72
Basic nitrogen, 59
Benzenesulfonyl test, 144
Bromine addition, 32
Bromine test, 137
Carbohydrates, 82
Carboxyl group, 57
Diazonium compounds, 67
Diazotization, 63, 144
Dimethylsulfate test, 135
Duclaux values, 57, 139
Enols, 43
Esters, 47, 140
Ethers, 48
Fehling's solution, 83, 143
Ferric chloride test, 56, 137
Fuchsin test, 46, 142
Furfural formation, 86
Halogen compounds, 38, 135
Hydrazines, 66, 71
Hydrazo compounds, 71, 73
Hydrolysis test, 145, 146
Imides, 71
Indifferent nitrogen, 68
Iodoform test, 53, 137
Isocyanates, 71
Ketones, 42, 43, 46
Neutral equivalent, 138
Nitriles, 71
Nitro compounds, 71, 72, 145, 146
Nitroso compounds, 71, 72
Osazones, 71, 84, 85, 144, 155
Oximes, 71
Pentoses, 86
Phenols, 55, 57, 136
Phenylhydrazones, 44, 142, 143
Phenylisocyanate test, 50
Phthalein formation, 137
Phthalic anhydride test, 51, 62
Reactive esters, 53
Reactive methylene, 43
Reducing agents, 69
INDEX
247
Classification reaction:
Reduction tests, 145
Saponification equivalents, 140
Semicarbazones, 71
Silver nitrate test, 46, 135, 142
Starches, 87
Sulfides, 76
Sulfite addition, 45, 141
Sulfonation test, 134
Sulfones, 77
Sulfonic acids, 78
Sulfoxides, 77
Sulfur compounds, 75
Sulfuric acid test, 30
Tertiary alcohols, 50
Tertiary amines, 65
Thiols, 76
Unsaturation test, 31, 133, 134
Van Slyke method, 88
Volatility constants, 57
Cocaine,/-, 203
Codeine,/-, 203
Coniferin, 218
Confine, 95, 200
Coumaric acid,o-, 208
acid,p-, 208
Coumarin, 224
Creatin, 204
Creatinin, 94, 198
CresoI,m-, 209
,0-, 209, 210
,p-, 209, 210
-phthalein,o-, 211
-sulfonephthalein,o-, 213
Cresyl acetate,o-, 221
benzoate,m-, 224
benzoate,o-, 223
benzoate,p-, 224
methyl ether, m-, 219
methyl ether,o-, 219
methyl ether, p-, 219
p-toluenesulfonate,o-, 239
Crotonic acid,Q:-, 192
Cumene, 227
Cyanamide, 194
Cyano-acetic acid, 192
Cyano-benzoic acid,p-, 208
-hydrins, 71
Cyanuric acid, 212
Cyclo-heptanone, 215
-hexane, 190, 227
-hexanol, 215, 216
-hexanone, 190, 215
-hexylacetate, 221
-hexylamine, 194
-pentadiene, 226
-pentanol, 215
-pentanone, 215
Cymene,p-, 32, 227
Cystine, 87, 213
D
Decyl alcohol,?*-, 216
Dehydracetic acid, 214
Derivatives:
Acetone, 154
Acid phthalates, 152
Acids, 157
Alcohols, 150
Aldehydes, 153
Amines, 160, 161
Anhydrides, 160
Carbohydrates, 155
acetyl derivatives, 156
hydrazones, 156
mucic acid, 156
osazones, 155
Characteristics, 148
Dinitrobenzoates, 151
Diphenylurethanes, 159, 160
Esters, 157, 158, 160, 164
Glycol benzoates, 151
Halogen compounds, 163, 165
Hydrocarbons, 163, 165, 166
Nitrogen compounds, 161
Osazones, 155
Oxidation of side-chains, 165
Oxidation products, 152, 154
Oximes, 153
Phenols, 159
Phenylhydrazones, 153
Phthalimides, 164
Picrates, 166
Semicarbazones, 153
248
INDEX
Derivatives :
Solid esters, 158, 164
Toluidides, 157
Urethanes, 152
Dextrins, 197
Dextrose, 197
Diacetin, 190, 196
Diacetone alcohol, 190
Diacetyl, 189
-dioxime, 212
-N-methyl-p-aminophenol, 233
-monoxime, 195
morphine, 204
-7w-phenylenediamine, 236
-o-phenylenediamine, 236
-7>phenylenediamine, 236
Diallyl, 226
-amine, 194
Diamino-chlorobenzene,2,4-, 202
-diphenylmethane, /);/-, 202
-phenol,2,4-, 194, 198
Diazoaminobenzene, 238
Diazotization, 63, 67, 144
Dibenzenesulfonylaniline, 240
Dibenzoylmethane, 214
Dibenzyl, 228
-amine, 201
-aniline, 202
-carbamide, 236
ether, 219
-idineacetone, 217
ketone, 216
sulfone, 240
Dibromo-aniline,2,4-, 202
-benzene,/??-, 230
-benzene,o-, 230
-benzene,/^-, 231
solubility, 11
-butane, 1,2-, 229
-naphthalene, 1,2-, 231
-propionic acid,a,/3-, 192
-thymolsulfonephthalein, 213
Dibutyl carbonate, 222
oxalate, 219
Di-w-butyl carbinol, 215
Di-7J-butylamine, 200
Di-n-butylaniline, 201
Dicarboxylic acids, 16
Dichloro-acetamide, 235
-acetic acid, 192
-acetone,a, 190
-acetone,a7-, 217
-aniline,2,4-, 202
-azoxybenzene, pp'-, 238
-benzaldehyde,2,4-, 217
-benzene,//;-, 230
-benzene,o-, 230
-benzene,p-, 231
-benzene sulfonic acid,2,5-, 199
-diethyl ether,a,a'-, 191
-ethyl carbonate,/3,/3'-, 222
-ethyl ether,a;,a'-, 218
ethyl ether,a,/3-, 218
-ethyl ether,^,^'-, 219
-hydroquinone, 211
-methyl ether,a,a'-, 191
-4-nitroaniline,2,6-, 234
nitrobenzene,2,5-, 232
-phthalic acid,3,6-, 208
-propane,2,2-, 228
-propyl carbonate,7,7 -, 223
-toluene,2,4-, 230
Dicyano-diamide, 198
-diamine, 198
Dielectric constants, 12
Diethyl-amine, 193
-aminoethyl alcohol,/3-, 194
-aminopropyl alcohol, 7-, 194
-aniline, 200
barbituric acid, 212
benzene,/n-, 227
benzene,o-, 227
benzene, p-, 227
bromoacetyl carbamide, 235
-carbanilide, 235
ketone, 189, 215
sulfate, 239
Diglycohde, 191, 224
Dihydronaphthalene, 220
Dihydroxy-naphthalene,l,2-, 210
-naphthalene, 1,4-, 211
-naphthalene, 1,8-, 211
-stearic acid, 207
Diiodobenzcne,p-, 231
Diiso-amyl, 227
-amylamine, 200
INDEX
249
Diiso-propyl ether, 218
Dimethyl-acetal, 189, 218
-amine, 193
-amino-4-aminobenzene,l-, 202
-aminobenzaldehyde,^-, 202
-aminoazobenzene,p,- 203
-2-aminobenzene,l,4-, 200
-4-aminobenzene,l,3-, 200
-aminoethyl alcohol,/^-, 194
-aminophenol,m-, 210
-ammophenol,p-, 202, 210
-aniline, 200
benzylamine, 200
carbanilide, 235
quinoline,2,4-, 201
quinoline,2,6-, 202
sulfate, 135, 239
sulfone, 195
-o-toluidine, 200
-p-toluidine, 200
Dinitro-6-aminophenol,2,4-, 211
-aniline,2,4-, 204, 236
-aniline,2,6-, 203, 235
-benzamide,3,5-, 234, 236
-benzene,m-, 233
-benzenes, 18
-benzoates, 151
-benzoic acid,2,4-, 207
-benzoic acid,3,5-, 208
-hydroquinone diacetate, 233
-naphthalene, 1,5-, 234
-phenol,2,4-, 210
-toluene,2,4-, 233
-toluene,2,6-, 233
-toluene,3,5-, 233
-m-xylene,4,6-, 233
Dioleine, 224
Dipalmitine, 224
Dipentene, 220
Diphenyl, 228
-amine, 234
-bromomethane, 231
-carbamide chloride, 225
carbonate, 224
-dichloromethane, 230
ether, 219, 220
-ethylenediamine, 202
-ethy]enediamine,s-, 203
Diphenyl-hydrazine,as-, 205
-methane, 227, 228
nitrosoamine, 238
-piperazine, 204
sulfide, 239
sulfone, 240
urethanes, 159, 160, 234
Di-?!-propylamine, 193, 200
Di-n-propylaniline, 201
Distearine, 224
Di-p-tolyl ketone, 217
Di-p-tolylamine, 234
Duclaux constants, 57, 139
Dyes, 96
E
Elaidic acid, 206
Elementary analysis, 121
Enols, 43
Epichlorohydrin, 215, 218
Esters, 47, 140, 158, 160, 164, 172
solubility of, 26
Estimation, see Analysis
Ethers, 48
Ethyl acetanilide,N-, 234
acetate, 189, 220
acetoacetate, 214, 221
aconitate, 223
adipate, 222
alcohol, 24, 50, 189
-amine, 193
-m-aminobenzoate, 201
-p-aminobenzoate, 202
-aniline, 200
anisate, 223
anthranilate, 201
benzene, 227
benzoate, 222
benzylacetoacetate, 223
benzylamine, 200
benzylmalonate, 223
bromide, 228
bromoacetate, 221
bromomalonate, 222
a-bromopropionate, 221
n-butylmalonate, 222
250
INDEX
Ethyl di-n-butylmalonate, 216, 222
n-butyrate, 220
caprate, 222
w-caproate, 221
caprylate, 222
carbamate, 195
carbonate, 190, 220
chloride, 228
chloroacetate, 221
chlorocarbonate, 220
chloroformate, 191
a-chloropropionate, 221
cinnamate, 223, 224
cyanoacetate, 237
dibenzylmalonate, 223, 224
dichloroacetate, 221
diethylmalonate, 222
disulfide, 239
ether, 189, 218
ethylacetoacetate, 222
ethylmalonate, 222
formate, 189, 191
gallate, 211
glutarate, 222
n-heptylate, 221
hippurate, 234
iodide, 228
isobutyrate, 220
isovalerate, 221
lactate, 190, 221
laurate, 223
levulinate, 222
malonate, 222
malonic acid, 193
mandelate, 224
mercaptan, 195, 238
methyl ketone, 189
methylacetoacetate, 221
methylaniline, 200
methylketoxime, 194
methylmalonate, 222
-/3-methyl carbamate, 234
-a-naphthyl carbamate, 234
nitrate, 194, 237
nitrite, 194, 237
TO-nitrobenzoate, 232
orthoformate, 190, 218, 221
oxalate, 190, 221
Ethyl oxamate, 235
oxanilate, 234
oxide, 189
phenacetin,N-, 234
phenoxyacetate, 223
phenylacetate, 222
phenylcinchoninate, 202
phthalate, 223
propionate, 189, 220
pyruvate, 190
saUcylate, 209, 222
sebacate, 223
succinate, 222
sulfide, 238
sulfite, 239
tartarate, 223
thiocyanate, 238
p-toluenesulfonate, 239
-o-toluidine,N-, 200
-p-toluidine,ISi;-, 200
trichloroacetate, 221
trichlorolactate, 224
n-valerate, 221
Ethylal, 189, 218
Ethylene bromide, 229
bromohydrin, 190
chloride, 229
chlorobromide,s,- 229
chlorohydrin, 190
-diamine, 197
glycol, 196
-glycoldiacetate, 221
iodide, 231
Ethylidene bromide, 229
chloride, 228
Eugenol, 209
methyl ether, 219, 224
Exhaustive methylation, 95
F
Fehling's solution test, 83, 143
Ferric chloride test, 56, 137
Fluorene, 228
Fluorescein, 211
Formalin, 189
Formamide, 194, 197
INDEX
251
Formanilide, 195, 234
Formic acid, 6, 191
Formyl diphenylamine, 234
piperidine, 194
Fuchsin test, 46
Fumaric acid, 17, 208
Furfural, 190
formation, 86
Furfuramide, 235
Furfuryl alcohol, 190
G
Galactose,cZ-, 197
Gallic acid, 208
Gasoline, 227
Geraniol, 216
Glucosamine,^-, 197, 198
Glucose, 197
Glutaric acid, 196
Glycerol, 196
a-bromohydrin, 196
a-chlorohydrin, 196
Qf-dibromohydrin, 216
)3-dibromohydrin, 216
a-dichlorohydrin, 190, 215
/3-dichlorohydrin, 190, 215
tribromohydrin, 230, 231
tributyrate, 223
trichlorohydrin, 229
Glycocoll, 87, 198
Glycogen, 197
Glycol dibenzoate, 224
Glycolic acetal, 190
acid, 192, 196
aldehyde, 197
Glycyl alanine, 89
Guaiacol, 209, 210
benzoate, 224
carbonate, 224
Guanidine, 198
Guanine, 93, 204
H
Halogen compounds, 38, 135, 163, 165
estimation, 168
Helicin, 197
Heptyl alcohol,n-, 24, 215
aldehyde,n-, 215
bromide,?!-, 230
Hexachloro-benzene, 231
-ethane, 231
Hexahydrobenzoic acid, 206
Hexamethylenetetramine, 198
Hexane,n, 227
Hexyl alcohol,?!-, 24, 215
alcohol, sec-, 215
aldehyde,?!-, 215
methyl carbinol,?!-, 215
Hippuric acid, 208
Histidine, 87
Homologj', 5
Hydantoin, 93, 198
Hydrazines, 66
Hydrazinobenzoic acid,p-, 205, 208
Hydrazo-benzene, 238
compounds, 71, 73
-toluene,o-, 238
Hydrazones, 71, 153, 156
Hydro-benzamide, 235
-cinnamic acid, 206
-quinone, 193
-quinone diacetate, 225
-quinone dimethyl ether, 220
-quinone monomethyl ether, 210
Hydrocarbon test, 134, 163, 165
Hydrolysis test, 145, 146
Hydroxy-acids, 102
-azoxybenzene,p-, 211
-benzaldehyde,?w-, 210
-benzaldehyde,p-, 210, 217
-benzamide,?w-, 211
-benzamide,p-, 211
-benzoic acid,???-, 18, 208
-benzoic acid,o-, 18
-benzoic acid,;?-, 18, 208
-benzyl alcohol,o-, 191
-butyric acid,a-, 196
-ethyl acetate,/3-, 190
-ethylbenzoate,?n-, 210
-ethylbenzoate,p-, 210
-mesitylene, 210
-methylbenzoate,7?-, 211
-3-naphthoic acid,2-, 208
-l-naphthylaldehyde,2-, 210
252
INDEX
Hydroxy-phenylglycine,p-, 208
-(luinoline,2-, 204, 211
-quinoline,8-, 202, 210
-wi-toluic acid, 2-, 207
-w-tohiic acid,4-, 207, 211
Hydroxy 1 group, 171
I
Imides, 71
Indene, 226, 227
Index of refraction, 119
Indifferent nitrogen, 68
Indol, 202
Inert solvents, 9
Inosite,i-, 197
Inulin, 197
Inversion of sucrose, 86
Iodo-acetanilide,p-, 236
-acetic acid, 192
-aniline, m-, 201
-aniline,o-, 202
-aniline, p-, 2C2
-benzamide,??)-, 236
-benzamide,o-, 236
-benzainide,p-, 236
-benzene, 230
-benzoic acid,o-, 207
-benzoic acid,/;-, 208
-benzoic acids, 18
-form, 231
-form test, 53, 137
-propionic acid, fi-, 192
-toluene,??!-, 230
-toluene,o-, 230
-toluene,/;-, 230, 231
Ionization constants, 20, 21
Isatin, 212
Isoamyl acetate, 221
alcohol, 24, 50, 190, 215
-amine, 193
-aniline, 201
benzoate, 223
bromide, 229
butyrate, 221
carbamate, 234
carbonate, 234
cbloride. 229
Isoamyl ether, 219
formate, 220
iodide, 229
isovalerate, 222
nitrate, 237
nitrite, 237
oxalate, 223
propionate, 221
salicylate, 209, 223
succinate, 223
Isoamylene, 226
Isobutyl acetate, 220
alcohol, 24, 50, 190
-amine, 193
benzoate, 222
bromide, 229
n-butyrate, 221
chloride, 228
formate, 220
iodide, 229
isobutyrate, 221
methyl ketone, 215
nitrate, 237
nitrite, 237
phenylacetate, 222
propionate, 221
succinate, 223
Isobutyr-aldehyde, 189
amide, 195, 198
Isobutyric acid, 6, 192
Isobutyronitrile, 194, 237
Isobutyryl chloride, 191
Isocaproic acid, 206
Isocapronitrile, 237
Isocrotonic acid, 192
Isocyanates, 71
Isoeugenol, 209
Isomaltose, 197
Isonicotinic acid, 204, 209
Isopentane, 227
Isophthalic acid, 209
Isopropyl acetate, 189
alcohol, 24, 50, 189
-amine, 193
benzoate, 222
bromide, 228
?i-butyrate, 221
chloride, 228
INDEX
253
Isopropyl formate, 189
iodide, 229
methyl ketone, 189
oxalate, 222
phthalate, 223
tartarate, 223
Isoquinoline, 201
Isosafrole, 219, 226
Isovaleraldehyde, 215
Isovaleranilide, 235
Isovaleric acid, 192, 206
Isovaleryl chloride, 191, 225
Itaconic acid, 196
Kerosene, 227
Ketones, 26, 42, 43, 46, 153
Kjeldahl analysis, 167
Laboratory notes, 110, 130, 132
Lactic &cid,dl-, 196
Lactide, 191, 225
Lactonitrile, 194
Lactose, 197
Lsevulose, 197
Laurie acid, 206
Lauryl alcohol, 216, 217
bromide, 230
Leucine, 87
Leucomalachite green, 203
Levnlinic acid, 101, 192
Liebermann reaction, 72
Ligroin, 227
Limonene, 226
Linalool,?-, 215
Linalyl acetate, 222
Lysine, 87
M
Maleic acid, 17, 193, 196
anhydride, 225
Malic acid,Z-, 196
Malonamide, 198
Malonic acid, 193
acids, 101, 158
Maltose, 197
Mandelic acid,f^-, 193
acid,/-, 193
acid,dl-, 193
Mandelonitrile, 237
Mannitol,d-, 197
Mannose,d-, 197
Melamine, 204
Melting-points, 114
Menthane,p, 227
Menthene, 226
Menthol,/-, 217
Menthone,/-, 216
Menthyl acetate, 222
-amine,/-, 200
-benzoate,/-, 224
Mesidine, 200
Mesityl oxide, 215
Mesitylene, 227
Metaldehyde, 217
Method of analysis, 4, 108
Methoxy-benzaidehyde,o-, 216, 217
-benzoyl chloride, o-, 225
-quinoline,6-, 201
Methyl acetanilide, 203, 235
acetate, 189, 191
acetoacetate, 190, 214, 221
aconitate, 232
alcohol, 24, 50, 189
-amine, 193
-aminophenol,o-, 202, 210
-aminophenohp-, 202, 210
-7;-aminophcnol,N-, 194
n-amyl ketone, 215
-aniline, 200
anisate, 224
anthranilate, 201
anthranilic acid,N-, 207
anthraquinone,2-, 218
benzoate, 222
benzylamine, 200
bromoacetate, 190, 22
butene-1, 226
7i-butyrate, 190, 220
caprate, 222
caprylate, 221
carbamate, 195
carbonate, 189, 220
chloroacetate, 190, 221
254
INDEX
Methyl chlorocarbonate, 220
chloroformate, 191
cinnamate, 223, 224
citrate, 191, 225
cyclohexane, 227
cyclohexanols, 215
cyclohexene,2-, 226
cyclohexene,3-, 226
cyclohexene,4-, 226
diphenylamine, 201
ether salicylic acid, 206
ethyl acetoacetate, 221
formate, 189, 191
-d-glucoside,a-, 197
n-heptylate, 221
?n-hydroxybenzoate, 210
iodide, 228, 230
isobutyrate, 189, 220
isovalerate, 220
lactate, 190
laurate, 222
levulinate, 190, 221
malonate, 190, 221
malonic acid, 193
mandelate, 224
o-inethox>'benzoate, 222
methylacetoacetate, 221
N-methylanthranilate, 200
methylmalonate, 221
myristate, 224
naphthalene,^-, 227
naphthalene,|3-, 227, 228
naphthylamine,a-, 201
nitrate, 194, 237
-nitrobenzoate, 232, 233
orthoformate, 189, 218
oxalate, 192
palmitate, 224
phenacetin,N-, 234
phenoxyacetate, 223
phenyl carbinol, 216
phenylacetate, 222
phenylhydrazine,as-, 205
phthalate, 223
propionate, 189
n-propyl carbinol, 215
propyl ketone, 189, 215
pyruvate, 190
Methyl quinoline,6-, 201
red, 207
salicylate, 209
sebacate, 223
stearate, 224
succinate, 190, 191
sulfate, 195
sulfide, 238
sulfite, 238
tartarate, 191
thiocyanate, 238
p-toluenesulfonate, 239
-p-toluidine,N-, 200
-p-tolyl ketone, 216
urea, 198
w-valerate, 221
Methylal, 189, 218
Methylene-amine acetonitrile, 203,
237
bromide, 229
chloride, 228
-disalicylic acid, 208
iodide, 230
Mixtures, 176
Molecular weight, 120
Mono-acetin, 196
-bromoacetal, 219
-chloroacetal, 218
-oleine, 224
-palmitine, 224
-stearine, 224
Morphine, 204
Mucic acid, 156, 196
Myristic acid, 206
MjTistyl alcohol, 217
N
Naphtha quinaldine,/3-, 202
Naphthaldehyde,/3-, 217
Naphthalene, 228
solubility of, 12
-sulfonamide,a-, 213
-sulfonamide,(3-, 213
sulfonic acid,a-, 199
sulfonic acid,/3-, (anhydr.), 199
sulfonic acid,/3-, (trihydrate), 197
-sulfonylchloride.a-, 239
-sulfonylchloride,/3-, 239
INDEX
255
Naphthalene tetrachloride, 231
Naphthalic acid, 208
Naphthoic acid,a-, 207
acid,/3-, 207
anhydride, 225
Naphthol,a-, 210
,/3-, 211
-aldehyde, 1,4-, 211
-3,6-disulfonic acid,2-, 199
-6, 8-disulfonic acid,2-, 199
-4-sulfonic acid,l-, 199
-6-sulfonic acid,2-, 199
Naphtho-nitrile,a-, 237
,/3, 237
-phthalein,a-, 209
quinone,a-, 217
,^-, 217
Naphthyl-amine,a-, 202
-amine,/3-, 203
benzoate,/3-, 225
ethyl ether,a-, 219
ethyl ether,^-, 219, 220
isoamyl ether,/3-, 219, 220
methyl ether,a-, 219
methyl ether,/3-, 220
salicylate,/?-, 224
Narcotine, 204
Neutral equivalent, 138
Nicotine, 95, 194
Nicotinic acid, 204, 208
Nitriles, 71
Nitro groups, 71, 72, 145, 146
Nitro-4-acetaminotoluene,3-, 233
-acetanilide,m-, 234, 236
-acetanilide,o-, 233, 235
-acetanilide,p-, 234, 236
-4-acetylaminotoluene,3-, 235
-l-aminonaphthalene,2-, 203
-4-aminotoluene,3-, 203, 233, 235
-2-aminotoluene,4-, 203
-2-aminotoluene,5-, 203
-aniline,m-, 18, 203
-aniline,o-, 18, 202, 234
-aniline, p-, 18, 203
-anisole,o-, 232
-anisole,7>, 232
benzal chloride,m-, 233
-benzaldehyde,?^-, 233
Nitro-benzaldehyde,c-, 232
-benzaldehyde,p-, 233
-benzamide,m-, 233, 235
-benzamide,o-, 234, 236
-benzamide,p-, 234, 236
-benzanilide,™-, 233, 236
-benzene, 232
-benzoic acid,m-, 207
-benzoic acid,o,- 207
-benzoic acid,p-, 208
-benzoic acids, 18
-benzoyl chloride,??i-, 232
-benzoyl chloride,p-, 233
-benzyl alcohol, ??i-, 232
-benzyl alcohol,o-, 233
-benzyl alcohol, p-, 233
-benzyl bromide, p-, 233
-benzyl chloride,m-, 232
-benzyl chloride,o-, 232
-benzyl chloride, p-, 233
-benzyl esters, p-, 6, 158
-cinnamic acid,/«-, 208
-cinnamic acid,o-, 208
-cinnamic acid,p-, 208
-cymene, 2, 232
-dimethylaniline,m-, 202
-dimethylaniline,p-, 203
-diphenylamine,4-, 233
-ethane, 212
ethylacetanilide,p,- 233
-X-ethylacetanilide.p-, 235
-ethylaniline,m-, 233
-guanidine, 212, 234
-iodobenzene,o-, 232
-iodobenzene,p-, 234
-mesitylene, 232
-methane, 194, 212
-methylacetanilide,p-, 233
-methylaniline,p-, 233
-l-methylcyclohexane,l-, 232, 233
-naphthalene,Q:-, 233
-naphthalene,/?-, 233
-phenetole,o-, 232
-phenetole,p-, 233
-phenol, m-, 210
-phenol,o-, 210
-phenol, p-, 210
-phenols, 18
256
INDEX
Nitro-phenyl acetonitrile,p-, 233
-phenylacetic acid,p-, 207
-phenylhydrazine,p-, 205
-propane,n-, 212
-quinaldine,6-, 204
-quinoline,6-, 203
-toluene,m-, 232
-toluene, 0-, 232
-toluene, P-, 232
-o-toluidine,3-, 203
-o-toluidine,6-, 203
-p-toluidine,2-, 202
-p-toluidine,3-, 203
-urea, 212
-TO-xylene,4-, 232
-p-xylene,2-, 232
Nitrogen compounds, 161
Nitroso-benzene, 238
-diethylaniline,p-, 202
-dimethylaniline,p-, 202
-diphenylamine,p-, 212, 238
group, 71, 72
-methylaminobenzoate,/^-, 203
-methylaniline,/)-, 203
-naphthol,l,4-, 211
-«-naphthol,/3-, 211, 212
-^-naphthol,a-, 210, 212
-phenol, P-, 211, 212
Nonanedicarboxylic acid, 206
O
Octane,n-, 227
Octyl acetate, sec-, 222
alcohol, 24, 215
-amine, n-, 200
Oleic acid, 206
Orcinol, 192, 193
Orthoform, 203
Osazones, 71, 84, 85, 144, 155
Ose group, 82
Oxalic acid, 196
Oxalyl chloride, 191
Oxamide, 236
Oxanilic acid, 207
Oxanilide, 236
Oxidation, permanganate, 33
side-chains, 152, 154, 165
Oximes, 71, 153
Palmitic acid, 206
Papaverine, 203
Paraloain, 198
Para-n-butyraldehyde, 215
Paraldehyde, 190, 191, 215, 216,
218
Pentachloroethane, 229
Pentaerythrite, 197
Pentane, 227
Pentoses, 86
Peptides, 89
Peracetic acid, 193
Petroleum ether, 227
Phenacetin, 235
Phenanthraquinone, 102, 218
Phenanthrene, 228
Phenetidine,o-, 200
,p-, 200
Phenetole, 219
Phenetyl urea,p-, 236
Phenol, 192, 210
-phthalein, 211
-sulfonephthalein, 213
sulfonic acid,p-, 199
Phenols, 55, 57, 136, 159
Phenoxyacetic acid, 193, 206
Phenyl-acetamide,a-, 236
-acetanilide,a-, 235
acetate, 222
-acetic acid, 206
acetonitrile, 237
acetyl chloride, 225
-alanine,^//-, 204, 208
-aminoacetic iicid,dl-, 204, 208
benzenesulfonate, 239
benzoate, 224
carbamide, 235
cinchoninic acid, 208
cinnamate, 224
disulfide, 239
-ethyl alcohol,/3-, 216
-ethyl barbituric acid, 212
-glycine, 203, 207
-hydrazine, 205
-hydrazine test, 142, 143, 156
hydrazones, 44, 153, 156, 171
INDEX
257
Phenyl-hydroxylamine, 195
isocyanate, 236, 237
isocyanate test, 50
isothiocyanate, 239
-3-methyl pyrazolon-5,1-, 238
-morpholine,4-, 202
-a-naphthylamine,N-, 234
-nitromethane, 212
phthalate, 224
propionate, 222, 224
propiolic acid, 207
-propyl alcohol, 216
salicylate, 210
sulfoxide, 239
thiocarbamide, 240
thiocyanate, 239
-thiohydantoic acid, 213
o-toluenesulfonate, 239
p-toluenesulfonate, 239
p-tolyl ketone, 217
urethane,N-, 234
Phenylenediamine,TO-, 194, 198, 202
,0-, 194, 198, 203
,p-, 194, 198, 203
Phloroglucinol, 193, 211
Phorone, 215, 217
Phthalamide, 236
Phthalanil, 236
Phthaldehyde,o-, 217
Phthalein test, 137
Phthalic acid,o-, 208
acids, 18
anhydride, 207, 225
anhydride test, 51, 62, 152, 174
Phthalide, 224
Phthalimide, 212
Phthalimides, 164
Phthalyl chloride, 225
Physical constants. 111
properties and structure, 8
Picoline,a-, 194
Picolinic acid, 203, 207
Picramide, 236
Picrates, 166
Picric acid, 211
Picryl chloride, 233
Pimelic acid, 193, 206
Pinacoline, 215
Pinacone, 190, 191
hydrate, 191
Pinene, 226
hydrochloride, 231
Piperazine, 194, 198
hydrate, 197
Piperic acid, 208
Piperidine, 193
Piperine, 235
Piperonal, 217
Piperylhydrazine, 194
Poly-glycolide, 225
-hydroxy alcohols, 28
-oxymethylene, 197, 218
-substitution, 27, 99
Populin, 218
Procaine base, 202
Propiolic acid, 192
Propion-aldehyde, 189
-amide, 195, 198
-anilide, 235
Propionic acid, 6, 192
anhydride, 192
Propionitrile, 194
Propionyl chloride, 191
Propiophenone, 216
Propyl acetate,»-, 189, 220
alcohol, 24, 50
alcohol,n-, 189
-aniine,n-, 193
-aniline,^-, 200
benzene, 227
benzoate, n-, 222
bromide, n-, 228
n-butyrate,n-, 221
carbamate, n-, 195
carbonate, 7t-, 221
chloride, n-, 228
chlorocarbonate,n-, 220
formate,?!-, 189
iodide,n-, 229
nitrate, n-, 237
nitrite,?!-, 237
oxalate,/!-, 222
propionate, n-, 220
red, 207
salicylate, n-, 209
succinate,/!-, 223
258
INDEX
Propylene bromide, 229
chloride, 229
glycol, 196
Proteins, 90
Protocatcchuic acid, 208
aldehyde, 193, 211
Prussian blue, 123
Pseudo-cumene, 227
-cumenol, 210
-cumidine, 202
-ionone, 216
Purines, 93
Pyridine, 194
Pyrimidines, 93
Pyrogallol, 193
triacetate, 225
Pyromucic acid, 207
Pyrrol, 237
Pyruvic acid, 192
Q
Quercite,Z-, 197
Quinaldine, 211
Quinhy drone, 201
Quinidine, dextxo, 20 '\
Quinine, 204
Quinoline, 200
Quinolinic acid, 204, 208
Quinone {see Benzoquinone)
R
Raffinose, 197
Reaction solvents, 9, 19
Reactive methylene, 43
Reducing agents, 69
Reduction test, 145
Reference books, 7, 105, 175
Resorcinol, 193
diacetate, 223
monoacetate, 209
-monomethyl ether, 209
Resorcinyl dimethyl ether, 219
Rhamnose, 197
Rhodinol, 216
Rota classification, 97
Rules of solubility, 9
of substitution, 37
S
Saccharin, 213
Saccharose, 197
Safrole, 219, 226
Sahcin, 197, 218
Salicyl-aldehyde, 209
-amide, 211
Salicylic acid, 207
Santonin, 225
Saponification equivalent, 140^^-'
Sebacic acid, 207
Semicarbazones, 71, 153
Serine, 87
Silver nitrate tests, 46, 142
Sodium bisulfite test, 45, 141
decomposition, 122
Solubility prediction, 8, 131
reagents, 126
rules of, 9
tabl% 23, 24 {see rear cover)
tests, 126
Solvents, 9
Specific gravity, 120
Starches, 87
Stearic acid, 206
Stilbene, 226, 228
Strychnine, 204
Styrene, 226
Suberic acid, 207
Substitution rules, 37
Succinamide, 236
Succinanil, 236
Succinanilide, 236
Succininc acid, 193, 196
anhydride, 225
Succinimide, 195, 198
Succinonitrile, 195, 197, 237
Succinyl chloride, 192
Sulfanilic acid, 213
Sulfanihde, 213
Sulfides, 76
Sulfite addition products, 45, 141
Sulfoacetic acid, 199
Sulfobenzoic acid, 199
Sulfonal, 240
Sulfonation, 36, 134
Sulfonephthaleins, 213
Sulfones, 77
INDEX
259
Sulfonic acids, 78, 134
Sulfosalicylic acid,l,2,5-, 199
Sulfoxides, 77
Sulfur coinpounds, 75
Sulfuric acid test, 30, 126
Superposition, method of, 2
Sylvestrene, 226
Tannic acid, 208
Tartaric acid,ci-, 196
,dl-, 196
,i-, 196
Tartaric acids, 17
Terebene, 226
Terephthaldehyde, 217
Terephthalic acid, 209
Terpin, 217
hydrate, 217
Terpineol, 216, 217
Tertiary alcohols, 50
amines, 65
Tetra-bromobenzene, 1,2,4,5-, 231
-bromo-o-cresol, 211
-bromoethane,-s-, 230
-chloroethane,s-, 229
-chlorethylene, 229
-chlorophthalic acid, 208
-ethyl ammonium hydrate, 198
-hydroquinoline, 201
-methyl ammonium hydrate, 198
-methyl dibromoethane,s-, 231
-methyl p-phenylenediamine, 202
-methyldiaminobenzophenone, 204
-methyldiaminodiphenylmethane,
202
-nitromethane, 232
Theobromine, 93, 212
Theophylline, 93, 212
Thio-acetic acid, 195
-barbituric acid, 213
-benzamide, 213
-benzoic acid, 213
-carbanilide, 240
-cresol,?H-, 213
-cresol,o-, 213
-cresol,p-, 213
Thio-naphthol,/3-, 213
-phene, 238
-phenol, 213
-phthalic anhydride, 240
-salicylic acid, 213
-urea, 199
Thiols, 76
Thymol, 210
-phthalein, 211
-sulfonephthalein, 213
Thymyl acetate, 223
benzoate, 224
methyl ether, 219
Tolidine,o-, 203
Toluamide,p-, 236
Toluene, 227
-sulfinic acid,p-, 213
-sulfonamide,o-, 213
-sulfonamide, p-, 213
-sulfonic acid,/;-, 199
-sulfonyl chloride,o-, 239
-sulfonyl chloride,/)-, 239
-sulfonylaniline, p-, 213
-sulfonylethylaniline,p-, 239
-sulfonyl-p-toluidine,p-, 213
Toluhydroquinone, 193
Toluic acid,?n-, 206
acid,o-, 206
acid,p-, 207
acids, 18
Toluidides, 157
,P-, 6
Toluidine,»2-, 200
,0-, 200
,p-,202
ToluonitrLle,m-, 237
,0-, 237
,p-, 237
Toluquinone, 217
Toluylaldehyde,m-, 215
,0-, 216
Toluylhydrazine,/)-, 205
Triacetin, 190, 223
Triacetoneamine, 198
Triallylamine, 200
Tribenzylamine, 203
Tribromo-aniline,s-, 235
-anisole,s-, 220
260
INDEX
Tribromo-/cr/-butyl alcohol, 218
-phenetole,s-, 220
-phenol, S-, 210
Tri-M-butyl carbinol, 216
Tri-n-butylamine, 200
Tributyrin, 223
Trichloro-acetic acid, 192
-aniUne,s-, 202, 234
-anisole,s-, 220
-tert-butyl alcohol, 217
-ethane, 1,1,1-, 229
-ethane, 1,2,2-, 229
-ethylene, 229
-lactic acid, 193
-lactonitrile, 195
-phenetole,s-, 220
-phenol,s-, 210
Triethyl-amine, 200
carbinol, 215
citrate, 223
Trimethylamine, 193
Trimethylene bromide, 229
bromohydrin, 190
chloride, 229
chlorohydrin, 190
cyanide, 197, 237
glycol, 196
glycol diacetate, 190
Trimyristin, 224
Trinitro-anisole,s-, 233
-benzaldehyde,2,4,6-, 233
-benzene,s-, 233
-benzoic acid,2,4,6-, 208
-phenetole,s-, 233
-toluene, 212
-toluene, S-, 233
Trioleine, 223
Trional, 239
Tripalmitin, 224
Triphenyl-amine, 235
-carbinol, 218
-chloromethane, 231
-guanidine, a-, 203
-methane, 228
-phosphate, 224
Tri-n-propylamine, 200
Tristearine, 224
a
Trithio-acetaldehyde,a-, 239
-acetaldehyde,/3-, 240
-formaldehyde, 240
Tryptophane, 87
Tyrosine, 87, 204, 209
U
Undecanoic acid, 206
Undecenoic acid, 206
Unsaturated hydrocarbons, 31
Unsaturation test, 133, 134, 170
Urea, 92
Ureides, 92
Urethanes, 152
Uric acid, 93, 212
Valeraldehyde.n-, 215
Valeric acid,?i-, 6, 206
Valerolactone,7-, 190
Vanillic acid, 208
Vanillin, 210, 217
Van Slyke method, 88
Veratrine, 204
Veratrole, 219, 220
Victor Meyer method, 51
Volatility constants, 57, 139
Xanthine, 93
Xanthone, 218
Xylene, m-, 227
,0-, 227
,p-, 227, 228
Xylenol, 1,2,4-, 210
,1,3,2-, 210
,1,3,4-, 209, 210
Xylidine,l,2,4-, 202
Xylose, 197
Zeiss! method, 172
DATE DUE
Oemco, Ifc
V.
/ells bindery inc.
Valtham, mass.
FEB. 19o8
QD271.K3
3 9358 00011428 7
•^^—•mt^rmmmrmmm^m
-I 'T-
271
K5
Karam, Oliver
\ Qualitative organic analysis.
Wiley, 1923.
11428
CHEM
BLDG
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