XAPOXW1AULK

AV17W AND WAX EX

I 81)

TABLE X.-—ACETYL VALUES OF OILS

Oil or fat
Acetyl value (average)
Oil or fat
Aeetyl value (average)

Castor .............
150
Fish ..........
41

Colza ..............
17
Olive .......
13

Cotton seed .........
13
Shark liver .....
IS

Croton .............
20

Abnormal Variation in Acetyl Values.—Certain abnormalities
in acetyl values should be noticed and due allowance made in
specific cases.

Since acetic anhydride is absorbed by the hydroxyl radical
it might be expected that free acids, free alcohols or partly
hydrolyzecl glycerides or other esters would show such absorption
and that their occurrence in oils or fats would cause these to
exhibit unusually high acetyl values. This is found to bo the ease
and, since the three classes of substances named above are the
direct products of hydrolysis, it follows that rancid oils or fats
will not give normal acetyl values. For example, hydrolysis of
stearin will yield free stearic acid, together with distoarin,
monostearin or glycerol, according to the degree of hydrolysis:

Stwrin

HaO-»C,H.OH(OC!18H«0),

C,H8OH(OC,8H,60),

MonoHtoariu

C,»H,B0,,

Stoane uoi<l

(i)

) +
Ij,0,, (2)

8flOa. (3)

Each of these reactions produces a hydroxylated compound,
which is capable of combining with acetic anhydride. The
calculated acetyl values of these substances arc* as follows:

TABLK XL— ACETYL VALIIKS OF HYDHOLYXKI) (iL

C3H6(OH)2OC1SH360 + HS0 -> C3JI6(()H), +

Olyc«rol

Compound

Distearin. . , .
Monostearin.
Glycerol.....

Aeetyl vu
H4.2
25IJ. 9
772.0