THE ALZYLATIOIJ OF BaiJZSWfi. TOLUfillE Ai^D NAPHTHALENE AIJD THE GHLOHIIJATION OF ACETYLENE DISSERTATION Submitted to the Board of University Studies of The Johns Hopkins University in Conformity with ii:equirements for the Legree of Loctor of i-hilosophy by Thomas Llorris Berry BALTIMOiffi JUNE 1923 \^^ oils" TABLE OF COlJTEiJTS Acknowledgement PAHT I. The Alkylation of Benzene, Toluene and ivaphthalene Introduction 1 The Present Investigation 2 Apparatus - Fig. I 3 The Ethylation of Benzene 4 Hatio of C5E5 to AIGI3 5 Examination of the Two Layers 7 Fig. 2 Ethylation of Toluene 16 Ethylation of Brom Benzene 17 Propylene and Benzene 19 Propylene and Toluene 33 Propylene and Naphthalene 35 Tetrahydro Benzene and Benzene 35 Summary 38 PAHT II. The Chlorination of Acetylene Introduction 40 Experimental 40 Conclusions 50 Biography 51 ACO0WL2DGE:,:ii:NT The author welcomes this opportunity to express his deepest sense of gratitude to Doctor lieid, under whose direction the first part of this work was done, and to Doctors Prazer, Patrick, Lovelace and Thornton for the in- spiration received in the lecture room and laboratories. Appreciation is also extended to the authorities of The Chemical .Varfare Service for permission to publish the work on the chlorination of acetylene, which work was done at idg-ewood Arsenal. TH3 ALETLATION OF B3NZSIIE, TOLUENE AUD NAPHTHALENE. Friedel and Crafts and later workers have shown that benzene may he alkylated by treating it with an alky^ halide in the presence of anhydrous aliuninum chloride - RCl ^ C6H6 ^1^1_3> C6H5R -»- HCl Balsohn-'- in preparing ethyl benzene modified the Friedel and Crafts reaction slightly. Instead of using ethyl chloride, he used ethylene and hydrochloric acid in proportions to give ethyl chloride - CgH^ -f- HCl > CgHgCl Since ethyl chloride and benzene react in the presence of alum- inum chloride to liberate hydrochloric acid, the total amount of hydrochloric acid required in comparison with that of ethy- lene is very small since it undergoes a cyclic process C2H4 4- HCl > CgHgCl HCl -H C6H5C2H5 ; in fact Balsohn later found that even traces of water vapor in the ethylene used were sufficient, on reacting with the aluminum chloride, to furnish the required amount of hydro- chloric acid. Balsohn's method consisted in bubbling ethylene through 1. Bull. SOG. Chim. (2) 31, 539 (1879). -2- a mixture of benzone and aluminum chloride at 70°- 90° C. Under these conditions ethylation takes place very slowly; consequently the practical importance of the reaction was at that time not realized. According to McDaniels-'- 1 volume of benzene at 80°C. dissolves two volumes of ethylene. Since this solubility is small it is important that the benzene be saturated continu- ously with ethylene if the best results are desired. This point was recognized by Milligan and Reid^ who used high speed stirring to maintain a condition of saturation; as a result they found that the obscure and apparently unimportant method of Balsohn was, in reality, a very practical one - a reaction which when performed with the aid of high speed stirring, far outrivaled the usual method in which a previously prepared alkyl chloride is employed. TH3 PRESENT INVESTIGATION. 1. To study more thoroughly certain features of the Friedel and Crafts reaction. 2. To apply the method of Balsohn in the alkylation of Benzene, Naphthalene and Toluene, using high speed stirring. 3. To study the chlorination of acetylene, using stirrin.Dr. 1. J. Phys. Chera. 15, 605 2. J. Am. Chem. Soc. 44. 206 -3- APPARATU3 . The stirrer as is shovra in Figure I consists of a disc two inches in diameter and three sixteenths of an inch thick with holes three sixtyfourth of an inch in diameter bored radially aroiind its periphery and terminating inside of a small cone at the bottom of the disc. The disc is screwed onto a tool-steel shaft which is connected by means of belts and an intermediate pxilley to a 1700 R.P.M. motor. /Vith the size of pulleys which were used speeds as high as 13,000 R.P.M. could be obtained. The gas to be used was, after preliminary drying and purification, introduced by an inlet tube ending just Tinder the cone and thrown out through the small holes by the centrifugal force of the rapidly rotating disc. A rather closely fitting iron tube was placed around the stirrer shaft and connected by suitable means to the frame of the stirrer. This tube passed through the rubber stopper of the reaction bottle and dipped below the surface of the liquid contained therein; in this way a perfectly gas-tight reaction chamber was obtained. Baffle plates were used to decrease the gyra- tory motion of the liquid. A condenser was attached at one end by means of an adapter to the reaction bottle, while the other end was connected to a receiver for unused gas. THE STHYIATIOK OF BJCUZENS. Tha ethylene used was of commercial variety but of a very high grade of purity. It was first passed through a gas meter. The difference between the amount of gas as represented by the gas meter and the amount of recovered gas was taken as the amount which had reacted. After passing through the gas meter, the ethylene was purified and dryed. by passing through two gas wash-bottles, one containing pyrogallic acid and the other sxilphuric acid respectively; and then through two drying towers filled with soda lime and another containg phosphoric anhydride. The gas was passed into the benzene-aluminum chloride mixture at such a rate as to allow only an occasional bubble to escape. This was found to be the method conducive to the best resiilts, since if the amount of escaping gas is large, it carries appreciably quantities of hydrochloric acid along with it and the reaction slows down to a very marked degree. In some cases it was possible to restore the original reactivity by passing in small quantities of dry hydrochloric acid along with the ethylene. In all of the experiments, the temperature was held at approximately 70°. It was found that the change of tempera- ture coefficient of the reaction within the interval 60°-90°C. is approximately zero. Throughout the work it was found that an incubation period of about twenty minutes before the passage of the ethylene, favored the reaction. Experience has shown that at any given Instant during the course of a reaction, a maximum rate of absorption of gas under the prevailing conditions can be obtained, only with one particular rate of stirring. If the rate of stirring be reduced below this point, a reduction in the rate of gas supply must be made; while on the other hand, if the rate of stirring is increased, a corresponding escape of gas takes place with the consequent loss of hydrochloric acid, and, as a resiilt the reaction slows down to a very marked degree. The rates of stirring ranged between 8,000 and 10,000 E.P.LI. RATIO OF C5H5 TO AICI3 It was desirable to know the relative proportions of benzene and aliuninum chloride which would afford a maximum rate of reaction. It is quite conceivable that if this ratio be either very large or very small a poor rate of reactions will be obtained. The Inclination is to use a large amount of catalyst with the hope of insuring a good rate of reaction; it has however been fo\md that an excess of aluminum chloride is Just as detrimental to the rate of reaction as an insuf- ficiency. The aluminiun chloride used in all of the experi- ments in one set was from the same lot. -6- Slnoe the usual course of a catalytic reaction is to in- crease up to a maximum and then decrease, a comparison of results can be obtained only by counting time from the in- stant at which the introduction of the ethylene is begun, since the rate of increase of reaction rate varies in the different experiments. In table I the rates of absorption for a period of 134 minutes after the introduction of the ethylene are listed for five different experiments in which varying relative amounts of aluminum chloride and benzene were used. TABLE I Ext. Molal I AICI3 latio C6H6 Z. C2H4 Absorbed Time Average Hate of Absorption cc. CgH^/Mol CgHg/LIin 8.5 58.6 134 114 10 60.9 134 120 13 138.5 134 200 22 104.4 134 133 44 4.8 134 10 It thus appears that better results are obtained when the ratio of aluminum chloride to benzene lies between 1 : 13 and 1 : 22 . Ratios greater than 1 : 13 give poorer results while a ratio as small as 1 : 44 gives practically no results. -7- EXMIIMTION OP THIi TWO LAYERS Friedel and Crafts^, Gustavson, Boeaeken and others have fotmd that in the Friedel and Crafts reaction, there are always two layers formed. A clear upper layer and a dark "brown, very viscous lower layer. They state that the upper layer contains mostly benzene and the low boiling products, i.e. the lower substituted benzenes, while the lower layer contains materials boiling at much higher temperatures. An explanation for this phenomenon makes its appearance on consideration of the various theories which have been proposed to explain the mechanism of the Friedel and Crafts reaction. Friedel and Crafts own theory was, that the aluminum chloride used combines with the benzene to form a compound CgH5.Al2Cl5 which later reacts with the alkyl chloride giving hydrochloric acid and a substituted benzene CgHgAlgClg + RCl -> CgHgR -V HCl This theory was later abandoned for the theory proposed by Gustavson*^ who attributed the condensation to the formation of addition products of aluminum chloride with three molecules of benzene AICI3.3 CgHg; products which have been isolated and analyzed. These addition products are attacked very easily by 1. Ann. Chim. Phys. 6, (1), 449 2. B. 12, 853; 13, 157; 16, 784; 33, 767. -8- alkyl chlorides: AICI3.3 C5H5 + 3 RCl -> 3 HCl -V AlClg.SCCgHsR) AICI3 -+ 3 CgHgE Boeseken-^ has shown that Gustavson's intermediate is formed only in the presence of traces of moisture. He also shows that Gustavson's assiimption, that one mol of AICI3 suf- fices for 3 mols of hydrocarbon and three mols of alkyl chloride, is not valid in certain cases, since in these one mol of AICI3 will condense only one mol of hydrocarhon and one mol of alkyl chloride. He contends that the aluminum chlo- ride confines with the alkyl halide and has isolated some of these compounds C5H5COCI.AICI3 -t- C5H5 -^ C5H5COC5H5.AICI3 Boeseken^ points out that in the formation of homologues of "benzene, a very small amount of AICI3 was sufficient to cause the reaction of a large amount of alkyl halide. This, he explained, was due to the inability of AICI3 to form very stable compounds with the reactants. All of the theories which have been proposed assume that !• Boeseken - A. ch. (G) 14, 467 E. Boeseken - Rec. Trav. 22, 301 aluninum chloride forms an addition product with the alky- lated benzene. If this be true, then we should expect to find at the end of our reaction, the most alkylated benzenes in corabination with the aluminum chloride. This point was investigated by first separating the two layers, as well as possible, by siphoning off the upper layer. The two layers were then treated separately with water to de- compose the aluininiim chloride complexes. The amounts of these complexes, in the upper layer, are very small as is shown by treating with water; practically no heat is evolved and only very small amounts of aluminum hydroxide precipitate. The lov/er layer, on the other hand, contains practically the whole of the aluminum chloride used and has to be decomposed extremely slowly and with constant cooling. The upper and lower layers were fractionated separately through a Vigreux column. It was found that the lower layer contained, by far, a higher per- centage of the more alkylated benzenes. The following ratios will indicate the relative molecu- lar amounts of the different ethyl benzenes appearing in the upper and lower layers. These calculations were made upon the basis of 1000 molecular weights of mono ethyl benzene appearing in the upper and lower layers respectively. •10- Rtm 4 12 Layer Mono Di Tri Tetr: Upper Lower 1000 1000 583 1943 122 698 47 199 Upper Lower 1000 1000 588 325 354 354 177 177 Upper Lower 1000 1000 94 354 42 125 Upper Lower 1000 1000 5253 7169 1128 3991 Penta 26 302 32 151 59 1622 59 270 1204 9018 1813 71 Prom the data given, it is quite apparent that there is a marked difference in the composition of the two layers. In run #£ the reaction was stopped in its early stage, i.e. after considerable quantities of mono- and di-ethyl benzenes had been formed. Run #12 was carried much further toward completion and as a restilt higher percentages of the more ethylated benzenes were obtained. In all of the runs which v/ere made, it was observed that an extraordinary high percentage of penta ethyl benzene was obtained in the lower layer as compared with that in the upper layer. In all of the experiments it was observed that the speed of the reaction increased up to a maximum, remained constant, and then began to decrease. Experiment #13 shows this rather clearly. In the following table the rates are given in cc. of ethylene absorbed with their respective periods of absorption. •11- # 13 Period of Absorption Min. CO Ab . of C2H4 sorbed per Min. 72 190 30 770 20 1300 30 1220 35 1350 15 1322 15 982 18 883 Fig. 2 is a graphic representation of these values. The manner in which the benzene was dryed had considerable influence on the reaction. Calcium chloride-dryed benzene on being stirred with aluminum chloride gave rise to hydrochloric acid fumes which hovered above the surface 6f the benzene. After the reaction had progressed for some time these fumes gradually disappeared. Reactions in which calcivin chloride dryed benzene was used appeared to be very sensitive to changes in temperature, rate of stirring and loss of hydrochloric acid, and further, maintained the maximum rate for only a I 200 1 ZOO llOO 1 000 900 0. &00 < N 600 <: ^00 _ J- 300 106/_ \ 1-i--:| i Time In h^l i nutes s 20 40 60 80 100 120 (40 ISO 180 ^oo zio z^q FLq' Z. -12- short period as compared to sodium-dryed benzene, which did not yield white fumes of hydrochloric acid on being stirred with alwnintun chloride. iixperiment #E gives a fair idea of the rate at which benzene can be ethylated. 5.83 mols of benzene were ethy- lated with 139 Z. of ethylene, in the presence of 60 g. of AlCl-3 over a period of 134 minutes. The average rate of ethylatinn being 1034 cc. of ethylene per minute. The above amount of ethylene was calculated from the products obtained which were - 123 g. Benzene 200 g. iithyl benzene 155 g. Di ethyl benzene 42 g. Tri ethyl benzene 18 g. Tetra ethyl benzene 13.5 g. Penta ethyl benzene 16 g. Hexa ethyl benzene It has been previously stated that the reactions were run so as to permit only an occasional bubble of ethylene to escape. In this experiment calculation shows that 97 % of the ethylene sent into the reaction bottle is present in the distilled products. In this experiment 3.85 mols. of benzene, 0.385 mols of AICI3 and 14.1 mols of ethylene were made to react over a period of 675 minutes. The products obtained were - -13- l/2 g. Benzene 4 g. Ethyl benzene 74i- g. Di ethyl benzene 305 g. Tri ethyl benzene 8E g. Tetra ethyl benzene 31 g. Penta ethyl benzene 154 g. Hexa ethyl benzene. It was not possible to ethylate the benzene directly to hexaethyl benzene with the apparatus which was used in this work, due to the increase in volume of the liquid mixture on ethylati6n. The volume change is about 100 °io for an ethylation of about 80 per cent. Experiment # 13 is interesting from the standpoint of the comparative ease of ethylation of benzene and diethyl benzene. A mixture of 2.E4 mols of diethyl benzene and 0,385 mols of aluminum chloride was ethylated at a rate of 900 cc. per minute for 233 minutes. In this experiment benzene and aluminum chloride were employed in the ratio of 1 : 5.7 and the average rate at which the ethylene reacted for a period of the first 134 minutes amounted to 257 cc. per mol of di- ethyl benzene per minute. This is a much higher rate than would have been obtained had benzene and aluminum chloride been used in the above proportions. If diethyl benzene ethylates at the same rate as benzene we would have expected a lower rate of absorption. It appeared throughout this work that alkylated benzenes alkylate with somewhat greater -14- ease than does benzene; in other words it is harder to sub- stitute the first alkyl group into the benzene ring than it is to substitute the second alkyl group. This experiment was stopped on account of the product solidifying in the re- action bottle and consequently preventing further stirring. There were obtained on separation - 447 g. Hexa ethyl benzene 32 g. Tetra ethyl benzene 4 g. Penta ethyl benzene 3 g. Residue The amount of ethylene which reacted in this experiment represents 822- % of the amount required to convert all of the diethyl benzene into hexa ethyl benzene. Of the amount of ethylene which reacted 86-2 % was accounted for in the hexa ethyl benzene obtained after centrifuging out the in- cluded oils. In experiment #14, 2.24 mols of tri-ethyl benzene were ethylated with 5.03 mols of ethylene; 6.385 mols of AlClg were used and the reaction run for a period of 248 mimites. The average rate was 240 cc. per minute for the first 134 minutes as compared with 257 cc. per mol of diethyl benzene as was stated in the previous experiment. From these results it appears that tri-ethyl benzene can be alkylated at ap- proximately the same rate as diethyl benzene but both of these at a greater rate than benzene. This reaction was -15- stopped before the products in the reaction bottle solidi- fied. On separation there were obtained - 345 g. Hexa ethyl benzene 10 g. Penta etliyl benzene 70 g. Tetra ethyl benzene 22 g. Tri ethyl benzene The amount of ethylene which reacted corresponded to 72-^ % of the amount required to carry all of the tri-ethyl benzene to hexa-ethyl benzene; of this amount 8C.1 percent went to form hexa-ethyl benzene. It was expected that by stirring gaseous ethyl chloride into a mixture of benzene and alumintim chloride that the ethylation would take place somev^at faster, since a certain amount of time must be consumed in its formation from ethy- lene and hydrochloric acdi. Commercial ethyl chloride after drying was passed into a mixture of benzene and aluminum chloride. In this reaction one mol of hydrochloric acid is liberated from each mol of ethyl chloride which reacts; con- sequently the escaping hydrochloric acid carried large amounts of ethyl chloride along with it and as a result a large loss was involved. On the whole, this method was very unsatis- factory as compared with that in which ethylene was used. The reaction between ethylene and benzene in the presence of AICI3 is exothermic and a cooling coil was placed aroimfl. the reaction bottle vixich was immersed in a water bath; this was used in case the mixture got above 70^0. •16- It was fotmd that the reaction was aided "by allowing the temperature to rise, at the "beginning, tmtil gentle re- fliLicing was taking place. The refluxing was allowed to con- tinue for several minutes, after which the mixture was cooled to 700C. Refluxing for short periods of time tended also to revive the reaction after it had slowed down. Two different boiling points are given in Beilstein for Hexa-ethyl Benzene namely 305°C. and 292°C. In this work a total of about 1400 grams of hexa- ethyl benzene were pre- pared; consequently, it seemed that advantage should be taken of this opportunity to obtain its boiling point. After 3 recrystallizations from hot alcohol, the boiling point as determined with a 400 g. sample was found to be 293°C. at 766 ETHYLATIOII OF TOLUNSKS. 3.04 mols of toluene were treated with ethylene at a rate of 811 cc. per minute for a period of 81 minutes. This re- presents a rate of 266 cc. per mol of toluene per minute. This is a greater rate of ethylation than could be obtained with benzene. On fractionation of the product under ordinary pressure the following fractions were obtained: Up to 120° C. = 45 g, 120 - 145° z 42 g, 145 - 160° = 47 g, 160 - 164° , 74 g, 164 - 171° - 33 g. -17- - mostly toluene - a mixture of dimethyl and ethyl benzenes - ortho- and meta-mGthyl ethyl benzenes - p. ethyl methyl benzene 1.3,5 trimethyl benzene and 1.2.4 trimethyl benzene 171 - 198° = 28 g. 1.2.3 trimethyl benzene and 126.96.36.199 and 188.8.131.52 metaethyl dimethyl benzene 198 - 203° 2 32 g. 3.5 diethyl -1-ipethyl benzene. This fraction had an intensive blue fluorescence. 203 - 207 = 33 g. 184.108.40.206 tetra methyl benzene 5 g. Residue. The ethyl-methyl benzenes have been prepared by the Pettig synthesis-^. ETHYLATION 0? BROM BSIIZSITS 2.83 mols of Brom Benzene were ethylated at a rate of 70 cc. per mol of brombenzene per minute for a period of 345 minutes using 0.375 mols of aluminum chloride. Toli^ene, on the other hand , was etlaylated at a rate of 266 cc. per minute per mol of toluene under nearly the same conditions. 1. Glaus - B. 18, 1121 vVroblewski - A. 192, 198 ?ittig & Gliazer - A. 136, 312 Jannasch & Deickmann - B. 2. 1513 -18- It appears that alkyl side chains Increase the rate at which the "benzene ring can be alkylated, while halogen substituents effect a retardation. Previous workers have shown, that AICI3 causes a shifting of halogen atoms in the benzene ring. This, as would be expected, took place in the ethylation of brombenzene. On fractionation of the product we obtained the following fractions: Up to 140° C. - 15 g. - a mixture of benzene and ethyl- benzene 140 - 180" r 135 g. Sthyl- & DlEthyl-Eenzene 180 - 204° z 47 g. - 2 brom-1-ethyl benzene 204 - £15° = 39 g. - 4 brom-1-ethyl benzene 215 -221' z 45 g. - Triethyl benzene and dibrom benzene 221 - 240° - 35 g. Brom-diethyl benzenes. 240 - 250" r 35 g. Decomposed with liberation of hydrobromic acid. Residue = 85 g. - Tar -19- PROPYIENE AND BSRZERS Gustavson-^ has shown, that when normal propyl bromide and isopropyl "bromide react with "benzene in the presence of alumintan chloride the same compound, namely isopropyl "benzene, is o"btained. It is evident from this that the alximinum chloride causes a transformation of the one form of propyl "bromide into the other. 2 Kekule and SchrOtter have shown that normal propyl "bromide under the influence of AICI3 splits off HBr and re- arrangement is brought about giving isopropyl bromide: H H H H Br H H-C-C-C-Br J^±ll^ H-C-C-C-H III III H H H H H H This action is a minimum at 0°C. From 60 g. of propyl bromide and 80 g. of Benzene, Gustavson obtained 20 g. of isopropyl benzene, a yield of 34%. Jacobsen^ prepared isopropyl benzene by the ?ittig method using 100 g. of isopropyl iodide and an excess of benzene. After a reaction period of 4 days he obtained 5 g. of isopropyl benzene, a yield of 7%. 1. B. n, 1251 2. Bl. (4) 3, 726 3. B. 8. 126U ■20- Liebman-^ prepared isopropyl benzene from benzal chloride and zinc methyl LI CU3 , . /CH, "^ CI CH3 ^ ^ ^^^3 Since isopropyl benzene can be prepared only very slowly by the above methods, which furthermore afford very low yields, it was hoped that the reaction between propylene and benzene in the presence of AICI3 would prove a better means for its preparation. Propylene was generated from isopropyl alcohol by drop- pinsr it upon raeta phosphoric acid at a temperature of 500°- 700° C. This method, although it yields propylene of a very high degree of purity, is undesirable from the standpoint of the destructive action of phosphoric acid upon the glass reaction vessel at this temperatiire. The action was such as to gradually eat away the bottom of a pyrex flask in the course of ten hours under running conditions. A slightly less pure grade of propylene (less reactive) can be obtained more readily, and in larger amounts, by pass- ing isopropyl alcohol vapor over pumice impregnated with ■^^2^3 ^^^ ^Q^^ ^"t a temperature of about 600°C. The pumice 1. Liebman - B. 13. 46 •21- so impregnated may be naed for a period of 6 - 8 months before yielding an undesirable grade of propylene. The propylene was collected in a tank over water and after passage through a gas-meter was purified as in the case of ethylene. The rate of reaction between propylene and the benzene- altuninum chloride mixture was much slower than when ethylena was used. This might be explained as being due to the in- crease in weight of the isopropyl radical over that of the ethyl radical. In experiment #18, 15 mols of benzene were treated with propylene at a rate of 122 cc. per minute or 8 cc. per minute per mol of benzene for a period of 1770 minutes in the presencf of 1.1 mols of AICI3. This is a rate of about l/25 that at wliich it was possible to ethylate benzene. The two layers on fractionation gave the following products: Top Layer Bottom Layer 35 g. up to 75°(b.p. 28°) 188 g. Benzene 54 g. Benzene 550 g. Mono Isopropyl Benzene 82 g. 135 - 155° 369 g. Di Isopropyl Benzene 32 g. 200 - 22C° 62 g. Tri 28i g. 220- 255° 15 g. Tetra " 16 g. 225 - 285° 15 g. Residue 75 g. Residue The molal relationship of these products existing in the two -22- layers, calculated upon the "basis of 1000 mols of inono- isopropyl benzene existing in each layer, is - Mono Di Tri Tetra Top 1000 : 497 : 66 : 13 Bottom 1000 : ^85 : EOO : 100 From this relationship it is apparent, as was the case with the ethyl benzenes that the bottom layer is relatively richer in the more highly substituted benzenes than is the upper layer. The crude product in this experiment differs from that obtained in the ethylation of benzene in that a fraction boiling below 75° was obtained and that further, the bottom layer always contained a high percentage of tar. The isopropyl benzenes which appear in the literature at the present time are - mono-, ortho- and meta-di and 1:3:5 tri- isopropyl benzene. By a study of the temperature intervals existing between the boiling points of the ethyl benzenes a very good idea was obtained as to the temperature limits between which the higher substituted isopropyl benzene fractions should be taken; after the boiling points of several of these higher products had been obtained it was apparent that the fractions had been cut within the proper ranges. In experiment #21, 14 mols of benzene were treated with 100 cc. of propylene per minute (7 cc. per min. per mol of benzene) for a period of 2551 minutes in the presence of 1.1 mols of illClg. The crude prodilcts yielded - ■83- Upper Layer Lower Layer 22 g. up to 75 2 g- 252 g. Benzene 53 g. 720 g. Liono Isopropyl Bnezene 119 g- 293 g. Di " 30 g. 29 g. Tri 11 20 g. Tetra " ti 5 g- 16 g. rlesidue Molal Ratio 77 g* Upper Layer 1000 : 299 23 : _ Lower Layer 1000 : 180 100 : 5 It was noted throughout this v/ork that the complexes of AlClg with the isopropyl benzenes were decomposed more slowly "by water than were the complexes "between AICI3 and the ethyl "benzenes. It "became the additional o"bject of this work at this point to prepare some of the higher isopropyl benzenes. It is apparent from the data so far presented that mono- and di- isopropyl benzene may be prepared in large amoxmts by the reaction between benzene and propylene. After several attempts to carry the reaction to such a stage that the products would consist largely of the higher alkylated benzenes it was found that time was saved by first isolating the lower products and then retreating these with propylene in the •84- presence of AlClr^. It was also interestiriR: to find out whether or not the isopropyl benzenes and propylene react with greater ease than benzene and propylene. In experiment #23, 3 mols of mono isopropyl benzene wer( treated with 42 cc. of propylene per minute (14 cc. per mol of mono isopropyl benzene per minute) for a period of 1655 minutes. Prom these results it is again apparent that an alkyl benzene may be alkylated with greater ease than benzene The two layers on fractionation yielded the following: Top Layer Bottom Layer 10 g. up to 75° 7 g. Benzene I.iono Isopropyl Benzene 2t g. ig. 20 g. Di " " ig. H9i g. Tri 33 g. 12 g. Tetra " " 7 g. 2 g. 7/hite oolid 10 g. Residue 5 g. The percentage of each product occurring in each layer is Mono Di Tri Tetra Top 0.73 % 4.38% 93.47c 1.85% Bottom E.04 1.5 82.1 14.3 In this experiment a total of 452^- grams of the tri iso- propyl benzene was prepared. This product contains about 92% of the propylene used in the experiment. ■26- In experiment #22, 10.6 mols of mono- iijopropyl benzene were treated with propylene at a rate of 16 cc. per mol of propylene per minute (total of 170 cc. per minute) for a period of 1388 minutes in the presence of 60 g. of AICI3. The total products from the two layers were fractionated and refractionated several times to gain an idea of the relative isomeric yields. The fractions obtained were: 17 g. up to 75° at 766 mm. 20 g. Benzene 75 - 90 ° i g. 90 - 152 220 g. Llono 152 - 156 (B.P. 152 - 154) 25 g. Mono- Di- 156 - 201 33 g. Mono- Di 201 - 203j 203 J - 204i (B.P. 204) 2044- - 205-1- 206 - 206V 206;^.: - 208^ 208^- - 209V (B.P. 209) 212 - 215 215 - 220 220 - 225 225 - 230 230 - 233 256 g. 1.3.5 Tri 233^-234'; (B.P. 234) 56 g. 2341 - 235V 46 g. 236V - 236^ 410 g. Mono- Di 22 g. 23 g. 23 g. 119 g. Ortho- D: 20 g. 35 g. 12 g. 11 g. 6 g. -26- 47 g. 236^ - 237^ 6 g. 238 - 239 9 g. 239 - 24C 15 g. 240 - 241 s g. 242 - 243 16 g. 243 - 246 61 g. above 246° It appears from this data that about 65/o of the di- isopropyl benzenes formed is the meta. Of the tri-isopropyl benzenes fromed, about lb% is symmetrical tri-isopropyl benzene. 250 g. of 1.3.5 tri-isopropyl benzene was treated with 56 1. of propylene in the course of 12 hours. This reaction went at an exceptionally high rate; it being possible to cause an absorption of 80 cc. of propylene per minute. The reaction was not allowed to go to completion. On cooling the products in the reaction bottle solidified. On purifi- cation it was found that a white solid had been formed which was identical with the 2 grams of white crystalline compound obtained in experiment #23. The fractions obtained from the crude material were: 5 g. 234 - 236 48 g. 236 - 245 14 g. 245 - 260 •27- 24 g. 260 - 265 15 g. 265 - 270 110 g. above 270 26 g. 'iVhite crystals. Several runs were made using tri-isopropyl benzene and it was found to be possible to run the reaction until the products solidified completely. A total of 65 grams of the white crystalline material was prepared. It was centrifuged free of included oils and recrystallized several times from alcohol. The material crystallized in the form of long white needles which had a melting point of 117° and a boiling point of 260° at 775 ram. This material was oxidized with a 7/'b soli^tion Oi' permanganate on a water bath for one month and an acid melting at 282° was obtained. This could have been either mellitic acid of m.p. 286° or the dianhydride of 220.127.116.11 tetra carboxylic acid of melting point 286° C; hov/ever it would not be expected that the anhydride of this acid would be formed under the given conditions. The silver salt of this acid was prepared and gave an analysis 65.42 % Ag, the theoretical for s41ver mellitate being 65.82 °lo^ while the theoretical for the silver salt of benzene tetra carboxylic acid is 63.32 /b. The boiling point of the hydrocarbon (260° at 775 mm.) indicates that it Is tetra isopropyl benzene rather than hexa isopropyl benzene since its boiling point lies far belov/ that of hexa etiiyl -28- benzene (294°); also oils boiling above this were obtained (E65^° and 270°C.) which are thought to be tetra isopropyl benzenes. Mirtirros of oils boiling even higher than 270° were obtained but in insufficient quantities for separation. The 18.104.22.168 tetra methyl benzene boils below its two isomers, it being a solid while the isomers are liquids at room tem- perature. The boiling points of the hexa alkyl benzenes in- crease with increasing complexity of the alkyl groups as would be expected, hexamethyl benzene boiling at 254 ° and hexaethyl benzene at 294°; therefore we should expect hexa- isopropyl benzene to boil higher than 294°C. A combustion was made on this hydrocarbon and the following analysis obtained. Sample Theoretical For Hexa Penta Tetra % C 87.43 87.18 87.41 87.72 87.60 fo H 12.43 12.82 12.59 12.28 12.61 Since p. diisopropyl had not been made, considerable time v/as spent in trying to locate it within the range of the boiling points of the meta and ortho diisopropyl benzenes. The attempt to isolate this material failed, however, althoiigh it is thought that it boils between 212° and 216° since such -29- a fraction was obtained which was quite resistant to further separation. Hot enough of this fraction was obtained, how- ever, to effect an adequate separation. An attempt was made to synthesize para diisopropyl benzene by means of the Fittig synthesis. 240 grams of iso- propyl benzene were brominated with 321 grams of bromine in the presence of 30 g. of iodine at 0°C. On fractionation of the product there were obtained 290 g. of para brom- isopropyl benzene and 40 grams of oriho brom isopropyl benzene. Isopropyl chloride was obtained by refluxing isopropyl alcohol with an excess of concentrated hydrochloric acid, using a Hempel coltunn mounted by a 40" Vigreux column. By using this arrangement and carrying on the distillation so that the material does not distill above 50° a fairly rapid preparation of isopropyl chloride may be obtained. The para brom-benzene was mixed with its molecular equivalent of iso- propyl chloride and the mixture treated with the calculated quantity of sodium. The product on being separated yielded 75 g. of a fraction 150°-1570c. 300 g. of an earthy material. The fraction 15C°-157° was oxidized with permanganate, and benzoic acid of melting point 121°-122° obtained. It is evident from this that the bromine of para brom-isopropyl benzene was replaced by a hydrogen atom. This evidently came about as a result of the splitting off of hydrochloric -30- aoid from isopropyl chloride which thon reacted with the para brom benzene through the agency of the sodium to give isopropyl benzene. It was noticed while the reaction was tailing place that a gas was being liberated, this gas was evidently propylene. The earthy material was very light in v/eight, had a dark brown color and was insoluble in all of the common organic solvents; even on extraction with xylene for several days using a Soxlett apparatus nothing dissolved. The material burned in a manner much like cork and emitted a grayish smoke having a peculiar odor. This material is likely a polyphenyl compound. Jacobsen-'- states that it is very hard to put even one isopropyl group into the benzene ring by the Pittig Synthesis since the isopropyl halide is attacked with difficulty by sodium. After allowing brombenzene and isopropyl iodide to react for four days in the presence of sodium he obtained only a 5^i yield. Sprinkmeyer^ tried to prepare ortho iso- C ^- cymol ^yyj . y, from ortho brom toluol, isopropyl iodide f 1 ■" and I I sodium but failed to get any of the de- I J sodii tioweve sired product; he was however able to prepare small amoxmts of it from ortho bromcumol /■\_-\3,r • ^^'ti^yl iodide and sodi\im. 1.3.5 Triisopropyl benzene has been prepared 3. YhQ 1. Jacobsen - Ber. 8, 1260 2. iprinkmeyer - Ber. 34, 195 3. Comi^t. rend. 140, 940 ; C 1905 (11) 379; J. prak. Chem. 2 72.. 57 -31- 1.2.4 isomer was obtained as a result of the present work by refractionating the triisopropyl benzene fraction a number of times in a vacuiim using a pressure regulator. A total of 300 grains of this oil was obtained having a boiling point of 237°-237i° at 752.5 mm. and 97°- 97';-° under 4 mrn. It was oxidized for five days on a v/ater bath by a 7 percent solu- tion of permanganate. An acid melting with anhydride for- mation at 214° was obtained, this evidently is 1.2.4 benzene tri-carboxylic acid. The oil Ijad a specific gravity of 0.87644 at 0°C. and of 0.85928 at 250c. It had a color of + 18 as determined by the method recommended by the ^Imerican Society for Testing Ilaterials using a viscosity of 21.7 seconds at 100°?. for 30 cc. using a Sabolt Universal Vis- cosimeter; 30 cc. of v/ater under the same conditions gave a viscosity of 17.4 seconds. The index of refraction was found to be 1.4855 at 25°C. The oil gave a flash point of 205°:\ and a fire test of 245°i\ 200 grams of another oil were isolated. This had a boiling point of 270°C. at 766 mm. It had a color of -12 and flash and fire points of 240° and 280°?. respectively. The specific gravity was found to be 0.91283 at 0°C. and 0.89658 at 25°C. Its refractive index at 25°C. was found to be 1.5060. Its viscosity as determined with 30 cc. of oil was 45.7 seconds at 100°?.; the same amount of water at this temperature required 17.4 seconds. This oil was oxidized -32- with permanganate and an acid having a melting point of was obtained. About 60 grams of another oil was isolated. It had a boiling point of 265V°C. at 755.7 mr.i. and 10Zlr°C. at 4 mm. and refractive index 1.49G9. Color -7. The fraction boiling belov/ 75° was refractionated and fomid to be composed of two substances one boiling at 28°C. and t]ie other from 56°- 59°. The latter is likely diiso- propyl which has a boiling point of 58°C. The former had a specific gravity of 0.70949 at 0°G. 2.5 dibrom isopropyl benzene was prepared by brominating 120 grams of isopropyl benzene with 325 grams of bromine in the presence of iodine at a lov; temperature. 235 grams of a liquid boiling at 258°- 259° and having a refractive index of 1.5718 at 25° was obtained. This oil was oxidized with permanganate and an acid having a melting point of 151°C. was obtained; this is evidently 2.5 dibrom benzoic acid which melts at 151°-155°. -33- PROPYLSNil AlID TOLUSKi: Kel"be states that by treating toluene v/ith isopropyl iodide in the presence of alvj-ninun chloride meta i30c;>-mol is obtained. Flttig attempted to prepare para methyl iso- propyl benzene from para broratoluol, isopropyl iodide and sodiiun but failed to get the desired product^. However, Widman^ prepared it by the Pittig sjmthesis using para- brom-isopropyl benzene and methyl iodide. 7.2 mols of Toluene were made to react with 2-5- mols of propylene at a rate of 75 cc. per minute in the presence of ICO g. of AlClg. It is to be noted that this reaction goes somewhat faster than that between propylene and benzene. The product after purification was fractionated into the foil owing :- 5 g. Benzene 370 g. Toluene 1050-1200 17 g. Xylene I20O-145O 25 g. 145°-170° A mixture of trimethyl benzene and ortho c:,Tnene 161 g. 170°-185° of meta isocyraene (175-176) and cymene (para methyl isopropyl ben- zene) 175°-176° 60 g. above 185° If the fraction 170°- 185° be a mixture of meta-and para- 1. Ann. 210, 10 2. iUin. 149, 337 3. Ber. 24. 450 -34- methyl isopropyl benzenes , a possible separation could not be obtained merely by distillation, since both boil at the same temperature. The mon- brom derivatives of these com- pounds hov/ever, boil at about ten degrees apart; that of the meta compound at about 224° and those of the para at about 234°. 136^^- grams of the fraction 175-176, obtained by redis- tillation of the original 17C°-185° fraction, was brominated in the cold, using 10 g. of iodine as a carrier, with 162 grams of bromine. The product after being washed and dryed gave the follov/ing: 3.7 g. - 160°-195° C. 11.2 g. - 195^-220° 0. para 160 g. - 228°- 240°G 6 g. - 2400-2470C. £5 g. - Residue The fraction 228°-240°C. represents a yield of SO^-i of the brom derivatives of para- methyl isopropyl benzene, llelbe-'- states that by the Friedel and Crafts reaction using toluene isopropyl iodide and AlClg he obtained meta methyl isopropyl benzene. He obtained only a small quantity of his product and his method of identification which consisted in observing the solubility of barium salt of the corresponding di-carbox- ylic acid was unsatisfactory. 1. Ann. 210 . 10 -35- PROPYLENE AIID NAPTHAIEIIE Since ethylene and napthalene react only very slowly in the presence of iUCl^, it was to be expected that pro- pylene and napthalene would react even slower. Instead of propylene, diisopropyl benzene was used. 217 grams of napthalene was stirred with 132 g. of di- isopropyl benzene in the presence of 50 g. of AICI3 at a temperature of 90°C. for a period of 4-^- hours. The product on fractionation gave the following: 72 g. mono isopropyl benzene 15C°-185° 72 g. of napthalene 185°- 250° 15 g. isopropyl napthalene (264°-2660) 9 g. E66°-50C° probably diisopropyl napthalene. 50 g. of an oil boiling above 300° C. T3TRAHYDR0 BENZSHS AIJD BENZEIIE Since tetrahydro benzene contains an ethylene lini:age it was thought that it would react with benzene in the same manner as has been shov/n in the case of ethylene and pro- pylene. The product expected was phenyl cyclohexane :0: tc. - ^"v-; -36- 3.54 mols of totra-hydro benzene were mixed with 3.54 mols of benzene and treated very gradually with 60 grama of AICI3. On the addition of the AICI3 a violent reaction tool: place with the liberation of large amounts of heat. After the 60 grams of AICI3 had been added, the reaction bottle was connected with the stirrer. The mixture could not however be stirred for periods longer than 30 seconds, as the amount of heat liberated was sx;ch as to cause the liquid to boil. As the reaction proceeded the mixture could be stirred for increasing periods of time. After about 45 minutes it was possible to stir the mixture continuously and this was done for a period of five hours; during which the temperature of the mixture remained at about 55 degrees. At the end of five hours of stirring the temperature began to fall. The reaction product was purified and dryed and on distillation gave the following fractions: 30 g. up to 230° - mostly benzene, cyclohexyl chloride (141.3) and tetrahydro benzene 50 g. 2300-245° Phenyl cyclohexane 125 g. above 245° - lil:ely diphenyl cyclohexane and small amounts of dihexyl . Ilursanoff-^ prepared phenyl cyclohexane from cyclo- hexyl chloride, benzene and AICI3. 1. Ann. 518. 310 •37- To 100 grams of benzene and 10 grams of AlCl^ ho added slowly 50 grams of AICI3 he added slowly 50 grams of cyclohexyl c}iloride and obtained the following prodiicts: 10 g. up to 130° mostly benzene 34 g. 1300-1320 (10 mm.) Phenyl cyclohexane 1 drop 1320-200° (10 mm. ) 16 g. 2000-515° (20 mm.) diphenyl cyclohexane Ke showed that the latter was an ortho compound by prepar- ing it from ortho dichlorcyclohexane. Kursanoff states that the more AICI3 used the lower the percentage of phenyl cyclohexane obtained while the higher the percentage of higher boiling products. As an example of this he obtained a 11 percent yield 01 phenyl cyclohexane by using 30 g, of AlCl^, 20 g. of chlor cyclohexane and 40 g, of benzene whereas by using 0.1 g. of AICI3 under the same conditions he obtained a 68 percent yield of phenyl cyclo- hexane. This night explain why in the present work such a high percentage of higher boiling prodiicts were obtained. An effort was made to prepare phenyl cyclohexane by the Pittig synthesis. To 15 grans of finely divided sodium 65 cc. of alcohol free dry ether were added. A nixture of 35 g. of brom benzene and 35 g. of cyclohexyl bromide were then added. The reaction began immediately and cooling -38- was necessary for its control. After standing over ni.'^ht the product was distilled. A yield of 6-7 grans of phenyl cyclohexane was obtained which corresponds to about 18',>; - 20-/i of the theory. Phenyl cyclohexane has also been prepared by reducing diphenyl v/ith hydrogen in the presence of catalytic nickel"'-. SIMIARY 1. Benzene, Toluene and Ilapthalene may be alkylated readily by define and Polymethylene hydrocarbons in the presence of aliuniniim chloride with the aid of high speed stirring. By this method these alkyl compounds may be prepared more rapidly than is possible by the ordinary Priedel and Crafts reaction. 2. The rate at which alkylation will take place de- pends largely upon the relative amcants of aromatic hydro- carbon and aluminum chloride used. 3. The two layers which are always obtained in the ?riedel and Crafts reaction differ widely in the percentage of products present. The AlCl^ which is found almost wholly in the lower layer retains the higher boiling or more al- kylated products. 4. The lower alkyl benzenes may be alkylated with 1. 0(1912) 11, 191 -39- greater ease than benzene. 5. The larger the alkyl group the more difficult ii its entrance into the benzene ring. -40- II. THii CHLOI^INATIOIJ OF ACETYLENE The object of this work was to prepare tetra- and hexa-chloretharles from chlorine and acetylene using a liquid medium into which the two gases could be dispersed by means of a high speed stirrer, it was thought that saturation with water vapor, of the gases included within the Eiinute bubbles occasioned by the vigorous stirring, might cause a change in the usual course of the reaction. The reaction usually proceeds with explosive violence to give hydrochloric acid and free carbon. Chlorine and acetylene were introduced into the cone of the stirrer simultaneously by different inlet tubes. EXPERIMENTAL 500 cc. of water was placed in the reaction bottle and a run made at room temperature. Explosions took place continuously from the start which gave rise to numerous scintillations throughout the liquid. It was thought that by using a large excess of one of the gases that the ex- plosions could be prevented, but this was found not to be true. Explosions took place in every case irrespective of the richness of the mixture. It was then decided to pass the gases into boiling water v/ith the view that the increase ■41- in water vapor would tend to dilute the P:a3es and thereby reduce the violent action, iixploaions did not occur in any case with temperatures above 65° C. Sometime after this work was completed there appeared an riif^lish patent #174,6351 in which it was stated that the chlorination oi acetylene could be controlled in the presence 01 steam superheated to 400°-500° C. Motmeyrat^ has studied the action of chlorine on acety- lene. He states that ethylene dichloride in the presence of aluminum chloride at 70°-75° decomposes to give acetylene and hydrochloric acid (1) C2H4CI2 > C2H2 + 2 HCl He chlorinated C2H4CI2 under these conditions and got C2H2CI4. Assuming that reaction (1) does take place he accounts for the fact that no explosions occurred on chlorination by say- ing that there was a total absence of oxygen. If the presence of oxygen be the cause of the explosions then we would expect that on passing the gases through water, the dissolved oxygen would be expelled and that the explosions v/ould gradu- ally cease. This, however, was not the case. 1. Chem. Abs. 16, 1779 2. Bull. soc. chim. 19, 448 -42- Aftor the water had been stirred for one hour at a temperature of 80° using 350 cc. of Clo and 1400 cc. of C2H2 per minute, an emulsion was formed and very effective stirring was taking place. A current of air had to bo directed on the end of the exhaust pipe to prevent the exhaust gases from igniting. The fact that the exliaust gases after leaving the refl\r:c condenser would catch fire, Wiiile no explosions were occurring in the reaction bottle seeir.s to indicate that water vapor had a great influence in preventing explosions in the chamber; ot that due to the heating practically all of the oxygen was driven out. Refluxing began at 76° C After two hours at the above rates of flow the product was fractioned. Three drops of a coloi-less oil, heavier than water, having a boiling point at about 90° were obtained. This i)il has an odor which at first is etherial but on further inhalation becomes ex- tremely pxmgent. The odor was identical with that of di- chloracetaldehyde. It is known that acetylene and water react slightly to give acetaldehyde CgHg + HgO — ^ CH3CHO It is likely that a small amoimt of this compoiuid was formed, which on chlorination gave dichlor-acetaldehyde. After the water fraction had come over 50 g. of a color- less, odorless oil, boiling at 109° and having a specific gravity of 1.C889 was obtained. Theue physical duta do not check with those of any of the compoirnds which could be e:>rpected. THE CHLORIMTIOII OF ACiilTYLiillS BY THE USE OF SULPHUS DICHLORIDE Since acetylene coiild not be chlorinated under the conditions as set forth above, work was undertaken to study its chlorination by the use of sulphur dichloride according to the method of I.Iichel-'- . This consists in alternately passing chlorine and acetylene into a mixture of sulphur monochloride and 2% hydrogen reduced iron. I.Iichel simply allowed these gases to bubble through the mixture; he states that a good yield of hexa-chlorethane can be obtained in this waj^. The reactions v;hich take place are: (1) SgClg + Clg -^ 2 SClg (Z) CgHg ■\- 4 SClg -^CgHgCl^ +2 SgClg (3) CgHg + 6 SClg -^CgClg + 3 SgClg In the first experiment the temperature was so regu- lated that gentle reflxrxing took place, oince the reaction SgClg + Clg ^ 2 SClg 1. /ieit. Angew. Chem. 19, 1095 ■44- is exotherrdc and since fiirthor the 'boilinf? point of -jClg , which is being formed, is lower than that of SgClj), a cooling coil was placed aroimd the reaction vessel and the wliole immersed in an oil bath. The temperature at the begin- ning was held at 125°. Chlorine was stirred into 1057 g. of S2CI2 at a rate of 1500 cc. per minute for 10 minutes; total absorption talcing place. At the end of this period the entire contents of the reaction vessel was forced out of the liquid seal witli exj-^losive violence. This could have been d\ie to the instability of sulphur dichloride or to the clogging of the exhaust line. The latter was found not to have been the cause. In the follov/ing experiments the temperature during chlorinations was held at 40°; this seemed to help rather than hinder the rate of chlorination. The absorption of acetylene however occurred more rapidly at somewhat more elevated temperatures. The heat liberated during the ab- sorption 01 acetylene v/as used to raise the temperature of the mixture to about 80° C. It was not found necessary to remove the excess of acetylene by means of an inert gas such as COg before a new chlorination. The flow 01 chlorine was measured by a calibrated flow- m.eter, the acetylene by means of a wet meter. The chlorination of sulphur monochloride took place ■45- with eictroue ease; it being possible to get 1299 g. of the monochloride to absorb as high as 7000 cc. of chlorine per minute. In the case oi' the absorption oi" acetylene the reac- tion proceeded in a manner which is often found when work- ing with catalysts, namely that the reaction had to gradual- ly "build itself up". By this is meant that although at the beginning the catalyst might be distributed throughout the sulphur chloride medium rather homogeneously, the acety- lene woiild not be taken up at the same rate at which it would bo, after the reaction had been in progress for some- time. The rate of absorption of acetylene wotLLd always in- crease to a maximum and then gradually decrease. This phenomenon is not to be explained as being due to the pres- ence of small amounts of the chlorethanes, for even when they were present at the beginning, the reaction exhibited the same behavior. It is likely, however, that this behavior can be explained as being due to the formation of an inter- mediate compound betv/een Fe and CgHg; which compound later catalizes the reaction. After the reaction slowed down, the siilphur monochloride was chlorinated to the dichloride and this was distilled off. The remaining liquid was steam-distilled; this served to carry off the liquid tetrachlorethane from the solid hexa- chlorethane. In several experiments the sulphur chlorides -46- were decomposed with water, tlie liberated hydrochloric acid neutralised with IJagCOg, and the mixture sterna-dis- tilled. The residue consistinp of sulphur and hexachlor- Qthane was then extracted with ether. In order to get a closer estimate of the relative yields, two runs were made and the resulting products were worked up together. -47- RUII # 1 1299 S- OgClg : : 9. 61 mols. 25 g. Pe CHLORIII S Ac: :TYL3I!E Time flowmeter Rate Total Time Flowmeter Rate Total Min. P cc. Cl2 1. P cc. C2H2 35 8 2550 89.3 30 14 1000 30 61 6 2130 129.9 78 14 1000 78 96 219.2 45 14 1000 45 60 20 1220 73.2 213 226.2 110 6 2130 234.3 15 20 1220 18.3 2 11 3100 6.2 5 15 1040 5.2 16 24 4800 76.8 4 37 15 8 1040 750 4.2 317.3 9.8 128 37.5 11 42 7000 77 5 20 1220 ^6.1 20 20 4350 80.7 52 20 1220 63.4 23 12 912 21 31 157.7 80 00.5 27 24 4800 130 42 20 1220 51.2 65 20 1220 79.3 107 130.5 282 824 437 484.7 Average rate of chlorination = 2920 cc. per nin. or 2.25 cc. Gig per g. S„C1„ per minute. -48- The averarre rate oi acetylene absorption = 1100 cc. per minute, or 0.85 cc. CoHg per g. S^Clo per minute. The relative rates of chlorine uptake to acetylene uptake are apparently 3:1. V/eight of product z 1410 g. RUII # E 934 g. S2CI0 25 g. ?e Temp. 40° CHLORINE ACETYL3HE Time Flow- Ileter Rate at Total Gig Time ?1 ov/- 7/et Total C2H9 Rate Flow P. P. Leter L'-eter 71 ov/- P. P. meter Si. £. £. cc. 45 14 3.55 160 3 15 3.1 1040 101 8 89.2 75.8 750 46 14 3.55 155 87 8 61.5 65.3 750 52 14 3.55 184.6 102 8 72.2 76.5 750 57 14 3.55 202.3 701. 9 82 8 57.1 280 61.5 282.2 750 200 . 374 Yield of mixture of C2H2CI2 C2H2CI4 C2HCI5 1035 g. •49- The total products from "both runs amounted to 2445 g. which on separation gave tiie lollowinr percentaf^e by weifjht. B. P. Yield % C2C16 Sublimes 76 g. 3 C2HC15 158° 49 g. 2 C2H2C14 147° 1887 g. 77 CgHgClg 84° 108 g. 4 It is qixite evident that this method gives only a very small relative amount of hexachlorethane ; the main product being s-tetrachloretliane. The tetrachlorethane thus prepared was further chlori- nated to hexachlorethane in the presence of AICI3. This procedure is similar to that used by Llouneyrat by which he chlorinated ethylene dichloride to hexachlorethane. The chlorine was passed into the mixture at 120° C. The density increased with the chlorine absorption until a point was reached where the entire contents of the hottle solidified and could no longer be stirred. The hexachlor-ethane was freed as much as possible from the tetraclilor-othane by suction and the former then recrystallized from alcohol. The yield of CgClg calculated upon the basis of the amoixnt of chlorine used amounted to 63/i. The effects of stirring: at a rate of 8000 K.P.LI. on the •50- rate or absorption of chlorino by tetruchlorethano in tho presence of AICI3 was investigated at a point in the chlori- nation where the chlorine was being taken up at a rate of 1400 CO. per minute. The stirring was stopped with the result that the flow-meter pressure on the chlorine line dropped from 3 cm. indicating a rate of 1400 cc. per minute to 1 c:.:. indicating a rate of 750 cc. per minute. The latter rate is necessarily greater than it would have been, had not the liquid been previously stirred, since as soon as the stirring was stopped the AlCl^ was still rather homogeneously distributed throughout the liquid. C0NCLU3I01IS. 1. Chlorination of acetylene in the presence of 2% catalytic iron gives s-tetrachlorethane almost exclusively. E. s-Tetrachlorethane can be chlorinated in the presence of AlCl^ using high speed stirring until the reaction mixture solidifies, thus giving a yield of 63/0 hexachlorethane. 3. The effect of high speed stirring was to double the rate of chlorination of s-tetrachlorethane to hexachlorethane. 4. Chlorine and acetylene may be made to react without violence in the presence of water vapor above 65° C. BIOGiiAPHY The author of this dissertation was born in Charles Co., iJaryland, ii'ebruary 8, 1897. He received his early education in the public schools of Baltimore and graduated from The .JOhns Hopkins University in 1920 with the degree of Bachelor of Science. In the fall of 19E0 he entered the Johns Hopkins Graduate School of Ghe;nistry, taking as his subordinate subjects rhysical uhemistry and -lathematics . In June 1922 he received the degree of ..iaster of Arts, the title of his thesis being:- "The Friedel and Orafts Reaction. During the years 1921-22 and 1922-23 he was part-time instructor in Organic Chemistry at the Mt. 7ernon College of Baltimore and the University of Maryland respectively. He was appointed a Hopkins Scholar for the years 1920- 21. 1921-22 and 1922-23.