Nov., 1 9 2 0 T H E J O L ' R N A L O F 1 , V D U S T R I A L

TA3l.E IT-1.OO PER CENT SULFUR MONOCHLORIDE : 99.00 PER CENT B,~'-DtCHLOROETHYL SULFIDE

Baro- Manom- In- Increase Pressure metric eter crease Increase Pres- 100 G . Pres- Read- Pres- Volume per Unit sure Mustard

Time p m p . sure ing sure N. P . T . Volume V,T. Gas Hrs. C. Mm. Mm. Mm. Cc. Cc. Mm. Mm.

0 16 19 25 40 46 7 0 96

136 187

18 1 7 18 21 18 19 19 24 19 20

762 ... 7j21.5 796.5 24 772.5 806 34 771 830 59 768 833 65 767 850 83 765 860 95 761 880 119 765 857 92 767 862 95

0 5 . 2 6 . 0 8 . 0 9 . 3

11 .2 14.2 14 .2 13 .4 13.4

0 40 46 61 74 85

108 108 102 102

0 64.5 71 .8 95 .4

115.6 132.8 170 1 7 0 160 160

T A B ~ S 111-3.22 PLlR CENT SULFUR MONOCIfLORIDE : 96.78 PER CENT @,@'-DICHLOROETHY& SULFIDE

Baro- Manom- In- Increase Pressure metric eter crease Increase Pres- 100 G. Pres- Read- Pres- Volume per Unit sure Mustard

Time Temp. sure ing sure N . P . T . Volume V,T, Gas Krs. ' C . Mm. Mm. Mm. Cc. Cc. Mm. Mm.

0 16 19 22 40 46 72 96

144 187

18 17 18 20 18 19 25 24 21 20

i j i . 5 772.5 7 7 1 768 767 764 761 760 767

143 164 167 169 182 187 204 201 190 187

n 14.7 16 .8 18 .2 27.2 30 .8 4 2 . 7 40 .6 32 .9 30 .8

n n

T A B L E W-4.76 PER CENT SULFUR MONOCHLORIDE : 95.24 PER CENT B,B'-DICHLOROET"YI, SULFIDE

Baro- Mauom- In- Increase Pressure metric eter- crease Increase Pres- 100 G. Pres- Read- Pres- Volume per Unit sure- Mustard

Time Tzmp. sure ing sure N. P . T . Volume V,T, Gas Hrs. C. Mm. Mm. Mm. Cc. Cc. Mm. Mm.

0 16 19 22 40 46 72 89 96

144 187

18 17 18 20 18 19 25 22 24 21 20

... 772.5 772 7 7 1 768 767 764 762 i6 1 760 767

754 901 924 954

1040 1092 1220 1183 1190 1088 1053

0 129 152 183 272 325 456 42 1 429 328 286

75 91 93 95

106 1 1 1 121 121 120 110 107

0 21.3 24 .0 26 .6 41 .3 4 8 . 0 61 .3 61 . 3 6 0 . 0 46 .6 42 .6

0 162 182 202 314 365 466 466 456 354 324

0 328 368 409 636 738 944 944 924 716 656

When the apparatus was disconnected, small amounts of hydrochloric acid gas and hydrogen sulfide were detected in the gases liberated by the action of sulfur monochloride on the @,@'-dichloroethyl sulfide. Owing t o the solubility of hydrogen chloride in the latter substance, the increases in pressures shown in the tables and the accompanying plot do not actually represent the total gases produced.

C O N C L U S I O N S

I-'rhere is a decided interaction when small amounts of sulfur monochloride are placed in contact with large amounts of @#'-dichloroethyl sulfide.

2-This interaction is manifested by pressures re- sulting from the production of gases. The maximum pressure is reached a t the end of 3 days.

3-11 secondary reaction takes place between the substance and the gases, as indicated by a decrease in pressure a t the end of three days.

THE SOLUBILITY OF @@'-DICHLOROETHYL SULFIDE IN

TION BY EXTRACTION WITH THESE SOLVENTS1,Z By Thos. G. Thompson and Henry Odeen

PETROLEUM HYDROCARBONS AND ITS PURIFICA-

CIfEMICAL LABORATORY, EDGEWOOD ARSENAL, EDGEWOOD, MARYLAND Received May 5, 1920

The question of the solubility of dichloroethyl sul- fide in petroleum hydrocarbons has been investigated

1 Published by permission of the Chief of the Chemical Warfare Service. 2 The authors wish to acknowledge the advice and suggestions given

by Major Wm. Lloyd Evans and also the assistance received from Messrs. J. J. Alexander, J. H. Black, W. H. Gersdoroff, H. H. Harvey, Bruce Howard, J . L. Hutchinson, E. C. Mack, L. S. Minor, J. Parsons, G. T. Sobl, G. F. Seimers, M. C . Taylor, R. W. Tatem, D. R. Virtue, and C. J. Wernlund.

A N D E NGI ATE E RI hTG C H E M I S T R Y 1 0 5 7

for the purpose of ascertaining the suitability of such solvents as agents in extracting pure mustard gas from the crude commercial product. Its marked sol- ubility in the common petroleum hydrocarbons was quite contrary t o the belief commonly accepted in April 1918.

The method employed for the study of the inter- solubility of dichloroethyl sulfide and the petroleum hydrocarbons was essentially tha t used by R0thmund.l

NATURE A N D P R E P A R A T I O N O F MATERIALS

D I C H L O R O E T H Y L SULFIDE-The material which was used in the intersolubility experiments was obtained by double distillation a t a pressure of 13 t o 14 mm.

obtained from the conimercial material by distillation. Only tha t portion distilling below 100' was employed. The specific gravity of the distillate a t 24' C. was 1.6677. The nature of t h e other hydrocarbons used is illustrated by the distillation curves shown in Fig. I -

PET R 0 LE U M H Y D R 0 CAR B 0 S S- T h e ligroin utilized w a S

TEMPERATURE FIG. ~L-DI~TILLATIOX CURVES OF IlYDROCARBONS U S E D

SULFUR MONOCHLORIDE-This was obtained by dis- tillation of the commercial product, the portion boil- ing between 136' t o 138' C. being utilized.

SuLFUR-The pulverized C. P. rhombic modification was employed.

CHLORINATED MUSTARD GAs-This was made b y the interaction of distilled dichloroethyl sulfide with sulfur dichloride in a carbon tetrachloride solution below j o " C. The addition of the dichloride solution was gradual and accompanied with constant shaking. When t h e product was distilled a t 1 7 mm. pressure, the excess of sulfur dichloride and carbon tetrachloride distilled off first. The chlorinated product which came over a t I I 2 ' was collected separately and used in the inter- solubility experiments given in Table VI. I t was of a light brown color, and its specific gravity a t 2 2 '

was 1 . 3 j j . I N T E R S 0 L U B I L I T Y E X P E R I M E K T S

DICHLOROETHYL SULFIDE A N D LIGRoIw-The results obtained from a study of the intersolubility of dichloro- ethyl sulfide and ligroin at various temperatures are given in Table I and illustrated by the curve AA i n Fig. 2. The critical point of solubility, that is, t h e temperature above which the two substances would be mutually soluble in all proportions, was found t o be 19' C. The highest temperature a t which solid

1 Z . physik . Chem., 26 (1898), 433.

105% T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y 1701. 12, No. II

TEMPERATURE F I G . 2-INTERSOLUBILITY O F DICHLOROETHYL SULFIDE

AND HYDROCARBON SOSVSXTS

dichloroethyl sulfide could exist in the presence of its liquid phase and a ligroin solution of i t was 8.8' C.

TABLB I Per cent by Weight

Dichloroethyl Dichloro- Temp. -Ligroin- -Sulfide- ethyl c. Cc. Grams c c . Grams Ligroin Sulfide

13.0 13.0 12.0 10.0 9 . 5 . .~ 9 . 0 9.6

12.0 14.0 17.22 19.0 19.0 18.3 17.5 16.0 14.5 10.3 6.5 2.5 0.2

-2.5 -6.5 -7.5

0 0.00 1 0.67 2 1.34 4 2.67 5 3.34 6 4.00 7 4.67 8 5.34

6 9 6.00 12 8.01 19 12.69 24 16.03 29 19.36 39 26.04 49 32.72 59 39.39 79 52.75 99 66.10

119 79.46 30 20.03

Constant Constant ... . . . ... . . .

20 Constant ... . . . . . . ... ... . . .

... ... ... . . . . . . . . . 3.0 2.5 2.0 1 .5

25.44 Constant .. . . . . . . . . . . . . .. . . .. . . . . . . . . . . ..

3:h2 3.18 2.54 1.91

116 4 .9 9.5

11.6 13.6 15.5 17.4 19.1 23.9 33.3 38.6 43.2 50.6 56.3 60.7 67.5 72.2 75.8 83.9 86.3 88.7 91.3

100.0 97.4 95.1 90.5 88.4 86.4 84.5 82.6 80.9 76.1 66.7 61.4 56.8 49.4 43.7 39 .3 32.5 2 7 . 8 24.2 16.1 13.7 11.3 8 . 7

DICHLOROETHYL S U L F I D E A N D GASOLINE-The Critical temperature of solubility of dichloroethyl sulfide was found t o be 20.4'. The data obtained from these ex- periments are given in Table I1 and illustrated by the curve BB in Fig. 2.

TABLE I1 Per cent by Weight

Temp. -Sulfide-- -Gasoline-- ethyl Gaso- O C. Cc. Grams cc . Grams Sulfide line

Dichloroethyl Dichloro-

7.3 20.05 25.43 5.00 3.686 87.34 18.0 Constant Constant 10.00 7.371 77.53 20.4 . . . ... 17.75 13.095 66.02 18.7 . . . ... 30.00 22.113 53.49 14.0 . . . . . . 40.00 29.484 46.32 9 .5 . . . . . . 60.00 44.226 36.51 4.5 80.00 58.968 30.14 7.8 15:OO 19:03 3.80 2.801 87.17

13.5 Constant Constant 30.05 22.150 46.21 9.0 ... . . . 45.00 33.170 36.46 4 . 2 ... . . . 60.00 44.226 30.08

12.66 22.47 33.98 46.51 53.68 63.49 69.86 12.83 53.79 63.54 69.92

TABLE I11

Dichloroethyl Dichloro- Per cent by Weight

c. Cc. Grams Cc. Grams Kerosene Sulfide Temp. -Kerosene- -Sulfide--. ethyl

14.2 9.5

21.9 24.3 25.6 25.6 25.6 25.0 14.3 8.9

60 80

7 9

12 13 14 18 6 6

48.24 64.32

5.63 7.23 9.65

10.45 11.26 14.47 4.82 4.82

31.88 31.88 31.88 31.88 31.88 31.88 31.88 31.72 41.88 54.47

60.21

8.12

39.79 33.13 84.93 81.42 76.67 75.21 73.80 68.67 89.68 91.88

DICHLOROETHYL SULFIDE AND R A I L R O A D LIGHT OIL- The results secured in these experiments are shown in Table I V and illustrated by the curve DD in Fig. 2 .

The critical point of solubility was found to be 3 j ' .

TABLE I V ~ _ .

Railroad Dichloroethyl Railroad Dichloro- Temp. ---Light Oil- -Sulfide- Light ethyl c. c c . Grams Cc. Grams Oil Sulfide

25.0 28.0

, 31.3 37.0 35.0 33.0 23.6 20.9 14.5 9 . 3

1.926 14.95 4.024 25.00 2.940 14.95

10.760 Constant 15.869 ... 20.585 ... 30.316 ... 44.503 ... 59.005 ... 68.692 ...

18.966 31.715 18.966

Constant .... .... .... .... 54.48 47.95 38.49 29.88 24.33 21.64

From these results i t is evident tha t with the in- crease in the percentage of high boiling hydrocarbons, the critical temperature of solubility for these solvents and dichloroethyl sulfide will also increase. This is very nicely illustrated by a comparison of the solubility curves shown in Fig. 2 .

CARBONS-sulfur monochloride was found to be sol- uble in all proportions in ligroin, gasoline, kerosene, and railroad light oil a t temperatures above 0'.

SOLUBILITY O F SULFUR MONOCHLORIDE I N THE HYDRO-

PER CENT RAILROAD LIGHTOIL

100 90 80 70 60 50 40 30 PER CENT CHLORO-MUSTARD GAS

FIG. 3-INTERSOLUBILITY OF CHLORINATED MUSTARD GAS A N D RAILROAD LIGHT OIL

DICHLOROETHYL S U L F I D E A N D KEROSENE-Table 111 SOLUBILITY O F SULFUR I N LIGROIN-Ligroin Was shows the results secured from the study of the mutual shaken with powdered rhombic sulfur a t 0' and a t solubilities of dichloroethyl sulfide and kerosene a t room temperature for about 6 hrs. The excess of various temperatures. These determinations indicate sulfur was removed by rapid filtration. Twenty-five tha t the critical point of solubility of dichloroethyl cc. of the filtrates were pipetted into a weighed dish sulfide and kerosene is 25.6'. and the solvent evaporated, with the results given in 111 are illustrated in Fig. 2 by the curve CC. Table V.

The data given in Table

Nov, , 1920 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y I059

Temp. O c:.

0 n 2; 24 24.5 28

Sulfur in 25 Ligroin Gram 0.049 0.052 0.085 0.080 0.081 0.092

c c . TABLB V

Correction (Blank) 0.001 0.001 0.001 0.001 0.001 0,001

Corrected Weight 0.048 0.051 0.084 0.079 0.081 0.091

Sulfur in 100 Ligroin Gram 0.192 0.204 0.336 0.316 0.324 0.364

cc.

INTERSOLUBILITY O F CHLORINATED MUSTARD GAS A N D RAILROAD LIGHT on-The critical temperature of solubility of chlorinated mustard gas and railroad light oil was found t o be 8.3'. The da ta obtained in these experiments are given in Table VI and illustrated in Fig. 3 .

TABLE V I Per cent by Weight

Rail- Chlo- Railroad Chlorinated road rinated

Temp. Light Oil Mustard Gas Light Mustard ' C. Cc. Grams Grams 011 Gas ... 0 ... 1

Below -2 2 Below -2 3 Below -2 4

-1.8 5 1.0 6 3.3 7 4.7 8 5.8 9 6.7 10 7.3 1 1 7.7 12 8.0 13 8.2 14 8.3 15 8.3 16 8.3 17 8.2 18 8.1 19 8.0 20 7.95 21 7.90 22 7.85 23 7.80 24 7.7 25 7.35 30 7.0 35 6.6 40 6.0 45 5.35 50 3.85 60 2.0 70

-1.4 80 Below -2 90

0.000 0.791 1.582 2,373 3.164 3.955 4.74 5.53 6.33 7.11 7.91 8.70. 9.49 10.29 11.08 11.87 12.67 13.47 14.23 15.02 15.81 16.60 17.39 18.18 18.97 19.76 23.73 26.78 31.63 35.58 39.53 47.46 55.37 63.28 71.19

33.793 Constant

.... .... ....

.... . . . . . . . . ....

.... . . . . .... .... ....

.... . . . . .... ....

....

0.00 2.28 4.47 5.65 8.56 10.58 12.42 14.08 15.78 17.48 18.98 20.58 21.92 23.35 24.69 25.99 27.27 28.51 29.63 30.77 31.87 32.94 33.97 34.98 35.95 36.89 41.25 45.02 48.34 51.32 53.90 58.41 62.09 65.18 67.80

100.00 97.72 95.53 93.44 91.44 89.72 87.58 89.92 84.22 82.52 81.02 79.42 78.08 76.65 75.30 74.01 72.73 71.49 70.37 69.23 68.13 67.06 66.03 65.02 64.05 63.11 58.75 54.98 51.66 48.68 46.10 41.59 37.91 34.82 33.20

CONCLUSIONS FROM SOLUBILITY E X P E R I X E N T S

I--Dichloroethyl sulfide is soluble in the petroleum hydrocarbons and there is complete miscibility of the solute and solvent a t relatively low temperatures.

2--Sulfur monochloride is soluble in all proportions. g--Only a small amount of sulfur dissolves in the

petroleum hydrocarbons. 4--Chlorinated mustard gas is soluble in all propor-

tions of railroad light oil above 8 8' . APPLICATION OF RESULTS-AS the result of the data

given above, i t is self-evident tha t i t would be highly desirable t o take advantage bf the following facts in a method of extracting mustard gas from the crude commercial product, using petroleum hydrocarbons as solvents.

(I} Extract the crude mustard gas a t a temperature slightly above the critical point of solubility. Most of the sulfur, together with a tar-like mass, will re- main insoluble.

( 2 ) The supernatant solution is cooled considerably below the critical temperature, causing the formation of two liquid layers, the lower layer being primarily a solution of the hydrocarbon in the mustard gas. If the temperature be sufficiently lowered, solid mustard gas will precipitate out from the solution. This solid mass will-retain a little of the hydrocarbon.

( 3 ) The upper layer of hydrocarbon solvent, or tha t above the solid material, will contain all traces of sulfur monochloride together with chlorinated products of dichloroethyl sulfide in the crude mustard gas, and also certain amounts of dichloroethyl sulfide. The concentration of the latter will be a function of the temperature. This solvent may be used until the per- centage of products other than dichloroethyl sulfide makes i t undesirable.

(4) The lower layer will contain dichloroethyl sul- fide and certain amounts of the hydrocarbon, the per- centage of the latter being a function of the tem- perature.

SINGLE EXTRACTION

I n order to demonstrate tha t such a separation a s described below could be carried out, 2 0 0 cc. of crude mustard gas were shaken thoroughly with 2 0 0 cc. of ligroin in a separatory funnel a t a temperature of 44" C. The mixture was allowed t o cool very slowly to 25 '. Three well-defined layers separated. The heaviest one consisted of a pitchy mass composed largely of sulfur. The second layer, a solution of ligroin in di- chloroethyl sulfide, was drawn off in three portions and analyzed by weighing each portion and distilling off the ligroin. The amount distilled was obtained by weighing the residue. When the top layer, or the solution of dichloroethyl sulfide in ligroin, was cooled to 8 ' , two layers formed. The lower layer was drawn off and analyzed. The ligroin solution, or upper layer, was then cooled t o -10~. The dichloroethyl sulfide precipitated in the form of long, white needles, which upon melting gave a light yellow solution containing a little sulfur. The results obtained from the analyses of the layers containing the ligroin in a solution of dichloroethyl sulfide are given in Table VII .

TABLE VI1 Weight of

Purified - -. .- - - Total Temp. Weight Dichloro- Wt. of of Ligroin ethyl Melting Layer Layer Dissolved Sulfide Per Point Grams O C. Grams Grams cent O C. Remarks 14.8 25 0.3 14.5 66.3 25 8.7 57.6 21.6 2:6 Dark yellow 65.2 25 8.5 56.7 21.2 4.6 Dark yellow 26.1 25 3.75 22.35 8.4 5.0 Dark yellow 80.35 8 11.05 69.3 26.0 9.0 Light yellow 59.8 -10 23.50 36.3 13.6 12.5 Light yellow

5.4 Pitchy mass (S)

SUCCESSIVE EXTRACTION]

I n this process a series of superimposed funnels was used. A diagram of the apparatus is shown in Fig. 4. The general method of procedure was to place equal volumes of ligroin ( 2 0 0 cc.) in each of the funnels. An equal volume of crude dichloroethyl sulfide (zoo cc.) was then introduced in the top funnel. The con- tents of the first funnel were shaken, and the insoluble material which settled out from the ligroin layer was passed into Funnel 2 . This passage was slow, drop by drop. As the drops came in contact with the ligroin layer in Funnel 2 : they broke up into a fine spray, which scattered throughout the ligroin. The process was repeated in the succeeding funnels. Two

1 As the result of a large number of experiments with hydrocarbon solutions of mustard gas, i t was noticed tha t the toxicity of these solutions appeared to be greater than tha t of either the commercial or pure mustard gas. This matter was called to the attention of the Research Division in June 1918.

1060 T H E J O U R N A L O F I N D U S T R I A L

experiments, illustrating the general results obtained by this process of extraction, gave 76.5 and 80.9 per cent of ligroin-soluble material. This soluble material was distilled in vacuo ( 2 . 0 t o 5 .0 mm.) , and a yield of 86.98 per cent was obtained which showed a purity of 99.5 per cent (m. p. 13.75' C.). Better purification resulted from keeping the temperature of extraction a little below the critical point of solubility of the ligroin and dichloroethyl sulfide.

A N D E N G I N E E R I N G C H E M I S T R Y 1'01. 1 2 . NO. 1 1

DICHLOROETHYL SUL Fl DE

SOLUTION OFL/GRO/N IMDICHLOROPTHYL sULF/DE

EXTRA C T CLEAR, PALE YELLOW Ll80 CCJ

DAUK NOT CLEAR L2/3 cc.J SIRUPY MASS [ 2 m]

DICHL o ROE TH YL SULFIDE EXTRACT

DARKER THAN No. 1, CLEAR l 5 3 .cJ SIRUPY MASS [ Z c c j

CLEAR, LIGHT AM5ER 1265mJ

D K H L o R o E r H Y L SULFlD& ExmAcT CLOUDX F A I N T Y€LLOW c215&.] -

CLOUDY DARii BROWN SIRUPY

SIRUPY MASS Docs NOT BREAK UP IN DROP PIN^ iNTO L/GRQ/d LAYER 5ELQW [ Z C c J

6UEAK.S UP Bur SLIGHTLY E l S ~ . l

CLEAR, VERY SLIGHTLY COLORED ~ O S C C J

DARK SIRUPY MASS 113 CC.] StRUPY M A S S L2-J

FIG. SUCCESSIVE EXTRACTION APPARATUS

The ligroin solutions when cooled t o -IO' gave beautiful, long, white needles, which were permitted to melt slowly after decantation of the mother liquor. Upon melting, two layers were obtained, the upper layer consisting largely of the ligroin tha t had been retained mechanically by the crystals. A very good product was obtained in yields varying from 51 t o 63 per cent, depending upon the extent of concen- tration and degree of extraction. This dichloroethyl sulfide had melting points which varied from 10.4' t o I 0 . 8 O c.

In all cases of extraction i t was very difficult t o re- move the last traces of ligroin. A small amount of the hydrocarbon caused a considerable lowering of the freezing point. To determine the actual amounts of dichloroethyl sulfide contained in the various samples, distillation gave by far the more accurate results.

INSOLUBLE RESIDUE-This insoluble layer obtained from the fourth funnel in the successive extraction experiments was a thick sirupy mass and contained only traces of mustard gas. While the residues were not subjected to distillation, there was very good evi- dence that only very small amounts of mustard gas

were present. This is found in the fact t ha t the mus- tard gas dissolved in the ligroin and vice versa, and only a very small amount of ligroin is found in the insoluble residue. Further, this insoluble mass consists largely of sulfur, and the mustard gas is only sparingly soluble in sulfur.

ANALYSIS O F CRUDE MUSTARD G A S

The analysis of crude mustard gas used in all exper- iments herein reported was made as follows:

A measured volume of crude material was placed in a distilling flask of 7 5 0 cc. capacity, and the ffask at- tached t o a condenser, which was connected with a weighed receiver, and the system evacuated. The dis- tillations were made a t a pressure of 6 t o 13 mm. Upon heating the distilling flask, and before any dis- tillate was collected, there was a decided evolution of gas. While the last portion of the mustard gas was being distilled there was considerable bumping and frothing, and great care had to be manifested in com- pleting the work. The distillate was light lemon- yellow in color. The black residue in the flask con- tained quantities of sulfur, was insoluble in ligroin, and dissolved in carbon tetrachloride. Table V I I I gives the results obtained in two analyses.

TABLE VI11 Sample Sample No. 1 No. 2

261 200 194.7

74.6 Volume of distillate. cc . . . . . . . . 157

Per cent 7 7 . 7 78.5

Per cent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 24.65 23.3 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . .

Weight of residue, grams. ..................... 98.6 60.7

Volatile, grams., . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 4 . 6 5 . 6 Per cent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1 . 2 2 . 2

Freezing point of distillate, C. . . . . . . . . . . . . . . . . . 12.0 12.7 Purity, per cent. . . . . . . . . . . . . . . . . . . . . . . . . . 94 .2 96 .5

Percentage pure mustard gas. . . . . . . . . . . . . . . . . . . 69 .9 7 2 . 0 Average Percentage 71 .0

A N A L Y S I S O F CRYSTALS O F DICHLOROETHYL S U L F I D E

O B T A I N E D F R O M L I G R O I S S O L U T I O N

After removing as much as possible of the ligroin retained by the crystals, they were weighed out and subjected to distillation, the results being as follows :

TABLE IX Weight of sample, grams., ............................ 313.1

Melting point O C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7 . 4

Melting point, C . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 13.7 99 .3 89.08 25 .7

Weight of distillate, grams.. ........................... 278.9

Purity of distillate, per cent. . . . . . . . . . . . . . . . . . . . . . . . . . . . Per cent mustard gas in sample., . . . . . . . . . . . . . . . . . . . . . . Weight of residue. grams.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . _

P e r cent ......................................... 8 . 2 Weight of ligroin (by difference), grams.. . . . . . . . . . . . . . . . 8 . 5

Per cent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 2 . 7

Per cent mustard gas. . . . . . . . . . . . . . . . . . . . . . . . . . . . . 90.92 Per cent residue.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 9 . 0 8

Calculated as ligroin-free:

C 0 N TI N LT 0 US E XT R A CTI 0 iS

X E T H O D A N D APPARATUS-In order to have a con- tinuous process for the extraction of mustard gas from the crude material by means of ligroin, the apparatus shown in Fig. 5 was devised. The crude material flows from a separatory funnel into the main portion of the apparatus, which consists of a glass tube, about 4 f t . in length, with a bulb blown a t the upper end, which serves as a settling chamber, and a stopcock a t the lower end, which permits the removal of the in- soluble matter. The ligroin is introduced into the apparatus by means of a long glass tube, sealed into the side of the glass column about 6 in. from the bot -

Nov., 1920 T H E J O U R N A L O F I N D U S T R I A L AlVD E N G I N E E R I N G C H E M I S T R Y 1061

TABLE X Volume of ligroin used cc.. 1800 Volume accounted for,'cc.. ........................ 17 13 Volume of crude mustard gas used, cc.. 800

enters the apparatus just below the settling chamber, Volume accounted for, cc. . . . . . . . . . . . 796

uble matter settles slowly to the bottom of the tube.

tom. is nearly filled with ligroin.

is sprayed through the column of ligroin.

At the start the main portion of the apparatus The crude material, which

The insol-

........................ . . . . . . . . .

Insoluble matter a t Weight, per cent.. ....... 13.5 Volume, per cent.. . . . . . . . 12.3

Weight, per cent ........................... 17.4 Volume, per cent.. ......................... 17.9

Mustard gas crystallized

.....

L16P?OIN Weight, per cent. .. . . . . . . . . . . . . . . . 43.7

Weight, per cent . . . . . . . . . . . . . . . . 22.7

RS5EIPVOIR

Volume, per cent . . ......................... 24.0

D I C H L O W O E T H Y L ( c R U D E )

SVLFlPE

0 V Z ~ F L O W

Q

n INSOLU~LC ~ n r 7 ~ e .

FIG. ~ - c O N T I N U O C S EXTRACTION APPARATUS

Almost complete extraction should be assured, for as the mass settles toward the bottom, i t comes in contact with the fresh ligroin. The overflow outlet, near the top of the apparatus, consists of a tube sealed into the long glass column and bent downward a t right angles so tha t the liquid will flow into a container placed under i t . k large separatory funnel is utilized for the col- lection of the ligroin solution from the overflow tube. When this funnel is nearly filled i t is removed and placed in a cooling bath. The insoluble matter collecting a t the bottom of the apparatus is drawn off from time to time into a graduated cylinder.

BILITY--n/feasured volumes of crude mustard gas and of ligroin were placed in their respective reservoirs, and the extraction carried out as described above, a t tem- peratures varying from 2 5 " t o 2 7 ' , or several degrees above the critical point of solubility. The data are given in Table X.

EXPT. I. A B O V E THE CRITICAL P O I N T O F SOLU-

EXPT. 11. B E L O W THE CRITICAL P O I N T O F SOLC- BILITY-Eight hundred cc. of crude mustard gas were run through the ligroin a t 15' in the continuous ex- traction apparatus. The insoluble matter drawn off a t the bottom of the apparatus measured 745 cc. A large portion of this was ligroin which had been dis- solved by the insoluble material. This residue was passed through the apparatus four times. Proper regu- lation of flow possibly would have increased the effi- ciency of extraction. The ligroin solution was placed in the freezing bath, and the mother liquor from the crystals of mustard gas was utilized in further extrac- tion of the insoluble matter. The results obtained are given in Table XI. The weight of the insoluble matter was calculated from the data obtained in the previous experiment. It will be noted tha t the insoluble mat- ter a t extraction temperature in Expt. I , together with the insoluble matter a t 16" t o IS", gave a total volume of 308 cc. and weighed 3 3 2 g. After the fourth extrac- tion in this experiment (Table XI) , the total insoluble material was 290 cc.

TABLE XI Volume of ligroin used cc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1200 Volume of crude must&d gas, cc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 800 Weight of crude mustard gas, grams. . . . . . . . . . . . . . . . . . . . . . . . . . . . 1068.8 Volume of mother liquor (does not include that retained by insolubles

and crvstals). cc.. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 900 - . . . Insoluble matter, per cent . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36.3 5 1.6 1 2 . 1

Mustard gas frozen from ligroin, per cent. . . . . . . . . . . . . . . . . . . . . . . . Material retained by mother liquors (by difference), per cent. . . . . .

A portion of the mustard gas frozen out from the ligroin solution was taken for analysis after a large part of the mechanically retained ligroin had been removed by distillation. This product was distilled in a vacuum of about 13 mm., thus removing the ligroin still present. The oil bath was heated gently to go0, and then to 9 5 " t o 100'. The data in Table XI1 were obtained as the result of this analysis.

TABLE XI1 Weight of sample, grams. . . . . . . . . . . . . . . . . . . . . . . . . . . Weight of distillate, grams. . . . . . . . . . . . . . . . . . . . . . . . . .

3 1 1 , 2 277.8

. . . . . . . . . . . . . . . . . . . . . . . . . . 3 . 4 Per cent mustard gas (calculated on ligroin-free

C O N T I N U O C S E X T R A C T I O S O F CRUDE MUSTARD G A S

WITH K E R O S E N E A K D RAILROAD LIGHT O I L

O K A SEMI-COMMERCIAL SCALE

The object of the following experiments was to confirm the results of those carried out in glass apparatus on a laboratory scale and a t the same time t o simulate as closely as possible the conditions which would obtain in plant operation. The crude mustard gas was manufactured a t the Edgewood Plant of Edge- wood Arsenal on August 29, 1918. I t had a melting

1062 T H E J O U R N A L O F I N D U S T R I A L A N D E N G I N E E R I N G C H E M I S T R Y Vol. 12, No. 11

point of 8.5', was black in color, and on analysis by distillation showed 7 0 per cent pure mustard gas.

APPARATUS AND METHODS-TO minimize danger as much as possible the apparatus was set up in an im- provised laboratory out of doors. The extractor was an all-lead column with a brass valve a t the bottom, and of the same essential design as the glass extractor.

EXPT. 111-This experiment was exactly like Expt. I , excepting tha t the rates of flow of the crude mustard gas and the kerosene were much slower, and the tem- perature of extraction was higher. The kerosene used in this experiment was obtained from the mother liquors of the two previous experiments. The data obtained are included in Table XI I I .

I - I t s principal parts consisted of a I. 5 in. (inside diameter) lead pipe, with enlarged sections at the top and the bottom. These sections were used as settling cham- bers and gave the apparatus proper a length of 4 f t . A three-eighths inch vertical pipe, attached just above the lower settling chamber, was of sufficient length to furnish a pressure head which would cause a counter current t o flow through the apparatus when in opera- tion. The crude mustard gas was admitted through another vertical lead pipe entering at the top of the upper settling chamber and terminating a t the center of the 1.5 in. lead pipe, about 2 in. below the bottom of the settling chamber. A three-eighths inch heat- ing pipe, through which steam was passed when extract- ing at a higher temperature, ran throughout the length of the apparatus. A thermometer well was placed in the top of the apparatus in order t o measure the tem- perature of the effluent as i t left the overflow pipe. The apparatus had a volume of 7.5 liters. The acces- sories, such as containers, funnels, crystallizing vessels, etc., were of glass.

The extractor was operated by running about 4 liters of kerosene into the apparatus. The kerosene supply was then turned off and the material t o be extracted was run in a t a definite rate of flow. As soon as the extract came through the overflow pipe, the kerosene was again permitted t o flow through the apparatus. The insoluble matter was drawn off a t the bottom of the extractor from time to time.

EXPT. I-This and the following experiments were carried out in much the same manner as already de- scribed for continuous extraction.

The extract and the insoluble residue were run into tared bottles, and weighed. The bottle containing the extract was refrigerated a t about -15' for 3 hrs., after which time large needle-like crystals formed a compact mass throughout the liquid. During the re- frigeration t w o liquid phases settled out, the lower one black in color and very rich in mustard gas, and the upper orange in color and low in its mustard-gas con- tent. The crystals were permitted to melt and the two liquid layers which formed were separated and weighed. Each layer was relrigerated as before and the remaining liquid drained from the crystals, the weights of which were determined. A second, third, and fourth fraction of crystals were obtained from the lower layer on further crystallization. The upper, or kerosene layer, yielded only one fraction. I n draining off the mother liquor from the crystals the bottles were simply held in an inverted position for a few minutes. The data are given in Table XII I .

EXPT. 11-This experiment differed from Expt. I in tha t the rate of flow of mustard gas was slower in order t o insure more complete extraction. The results are given in Table XIII.

TABLE XI11

Temperature of extraction, C.. ........... Rate of flow

Mustard gas per minute, CC.. .......... Kerosene per minute, cc.. .............

Mustard as used Weigtt, kilos. ....................... Volume liters.. ...................... Meltinipoint O C.. .................. Specific gravit'y (30°), ................

Kerosene used Weight, kilos. ....................... Volume liters.. ...................... Specific'gravity (30'). ................

Expt. I 23-26

77 125

11.9 9 . 0 8 . 5 1.315

14 .0 17.5 0.800

Expt. I1 26-40

47 125

11.5 8.75 8 . 5 1.315

15.2 19.0 0.800

Expt. I11 50-60

50 83

11.9 9 . 0 8 . 5 1.315

12.55 14.75 0.800

Kerosene layer Weight, kilos ........................ 16.44 18.27 12 Specific gravity (30'). ................ 0.862 0.862 0.862 Per cent mustard gas crystallized.. ..... 11.9 10.1 18.9 Weight, kilos.. ...................... 1.95 1.84 2.31 Melting point ' C . . ..................... 11.6 9 . 6 Specific gravity (200). 1.192 1.216 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . Recrystallization, per cent. 9 . 9 .. Weight, kilos. .......................... 1 . 8 . . Melting point, C . . 11.8 . . Specific gravity., .................... 1.210

..................... Sp. gr. of mother liquor., ............. 0:SSO 0.850 0:870

Insoluble residue Weight, kilos ........................ 7.16 1 . 5 2.16 Percent ............................. 61.2 13.2 18.2 Specific gravity (ZOO). . . . . . . . . . . . . . . . . . . . 1.251 1.246

Mustard gas layer Weight, kilos ........................ 3.30 6 . 6 4 7.66

Specific gravity. ..................... 1.221 1.209 1.244 Per cent crvstallized.. ................ 84.3 82.5 68.3

Melting point, C.. .................. 6 . 6 6 . 3 6 . 5

Melting point C.. .................. 8 . 6 7 .7 7 . 1

Melting point C.. .................. 9.5 9 . 5 .. Specific gravit'y (20'). ................ 1.244 1.247 1.252

Specific graviiy (20'). ................ 1.246 1.248 .. Mustard gas from kerosene kilos. ...... 1.40 1.13 2 . 5 0 Mustard gas from mustard'layer kilos.. 2 .79 5.47 5 .23 Total from both layers, kilos.. . .'. ...... 4.19 6 . 6 0 7.73 Per cent yield ........................ 35.8 58.1 6 5 . 0

Per cent recrystallized.. ............... 98.4 96 .0 .. Summary

Analysis of the layers or crystals by means of dis- tillation is practically impossible, owing to the fact that a very large portion of the kerosene boils a t the same point as does the mt:stard gas.

PRACTICAL TESTS

A large amount of crude mustard gas was extracted with railroad light oil. The purified product, which contained railroad light oil, was placed in twelve 75 mm. shells. When these shells were exploded no flash resulted, showing tha t the hydrocarbon did not take fire. At the time of explosion a white cloud of smoke was produced.

CONCLUSIONS

I-The critical temperatures of solubility of dichloro- ethyl sulfide with the various hydrocarbons are as follows:

Ligroin.. ..................... 19" Gasoline.. ................... 20.4' Kerosene.. ................... 25.6' Railroad Light Oil.. ........... 37'

a-The critical temperature of solubility increases with the increase in the percentage of the more com- plex hydrocarbons.

3-The critical temperature of solubility of chloro- mustard gas is considerably below tha t of dichloro- ethyl sulfide.

4-Dichloroethyl sulfide can be extracted from the crude material, containing 71 per cent, t o give yields varying from 54 per cent t o 69 per cent.