1056 T H E J O U R N A L O F I X D U S T R I A L AATD E N G I N E E R I N G C H E M I S T R Y V O ~ . 1 2 , NO. I I

The sample of the mustard gas-SzClz mixture is then quickly introduced into the flask by means of a 2 cc. immersion pipet, and the flask is weighed again; this yields a sample of about 2 . 5 g. A known excess of a standard sodium thiosulfate solution is added, and the excess is titrated with a standard iodine solution, using starch as an indicator. It has been found tha t this back titration is quicker and yields more uni- form results than does the single direct titration with thiosulfate solution. The number of cc. of thiosul- fate solution used, multiplied by its S2C12 equivalent i n grams, yields at once the S2C12 content of the sample. From these data the percentage composition of the mustard gas-SzClz mixture can be calculated.

SUMMARY

1-The need of a chemical control of the sulfur monochloride content in the reaction mixture of the Levinstein process for mustard gas has been pointed out.

2-The availability of iodine liberation by sulfur monochloride as a means for determining the sulfur monochloride is discussed.

3-The accuracy obtainable and the accuracy re- quired by plant operations are presented.

4-The procedure for control operations is outlined.

The writers wish t o express their appreciation of the help and suggestions of Major Wm. Lloyd Evans, of the chemical laboratory of Edgewood Arsenal.

ACKNOWLEDGMENT

PRESSURES PRODUCED BY THE ACTION OF SULFUR MONOCHLORIDE UPON p,p'-DICHLORO-

By Thos. G. Thompson and F. J. Kopp ETHYL SULFIDE'

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

The purpose of this investigation was t o measure the pressures produced when relatively small concentra- tions of sulfur monochloride reacted with p,p'-di- chloroethyl sulfide.

E X P E R I M E N T A L

The apparatus consisted of manometers connected with pear-shaped flasks containing varying concentra- tions of sulfur monochloride and @,@'-dichloroethyl sulfide. The latter substance was prepared by double vacuum distillation of the crude commercial product over calcium chloride. After the second distillation i t showed a melting point of 13.6' C. The sulfur monochloride was purified by distillation a t 136" t o 138'.

All proper precautions were taken t o see that the apparatus was absolutely dry. I n sealing the flasks to the manometers, a long calcium chloride tube was used by the glass blower.

The actual volumes of the flasks, together with the portions of the tubes not filled with mercury and compasing an arm of each manometer, were measured. Proper ~ o l u m e corrections were made for the changing of the mercury in the arms of the manometers con- nected with the flasks.

In each case, Four different experiments were run. 1. Published by permission of the Chief of the Chemical Warfare Service.

the time, temperature, and barometric pressure were recorded every time readings of the manometer were made.

Expt. I served as a blank and was run with 50.4 g. of the pure mustard gas in the flask. The data are given in Table I. Expt. 2, the data fos which are found in Table XI, consisted of a mixture of 64.0 g. of the di- chloroethyl sulfide with 0.64 g. of sulfur monochloride. Expt. 3 (Table 111) contained 41.1 g. of t he pure mustard gas (96.78 per cent) and 1,37 g. of sulfur monochloride ( 3 . 2 2 per cent). Expt. 4 (Table IV) consisted of 4 9 . 4 g. of the pure mustard gas (9 5 .24 per cent) and 2.47 g. ofLsulfur monochloride (4 .76 per cent).

TABLE I-PURS ~,~'-DICHI,OROETHYL SULFIDE

Time TErnp. Pressure Volume Volume Hrs. C. Mm. N. P T. cc.

Decreased

0 16 19 22 40 46 72 89 96

144 189

18 17 18 20 18 21 25 22 24 21 20

751 745 748 753 746 756 767 760 763 758 750

66 .4 66.1 66.1 66.1 66.0 66.1 66.2 66.3 66.1 66.3 66.0

0.0 0 .3 0.3 0 .3 0 . 4 0.3 0.2 0.1 0 .3 0.1 0 . 4

I I I I 1 I

The tables show tha t a maximum pressure is reached in approximately 7 2 hrs., after which time a steady decrease is noted. I n several previous experiments the same decrease in pressure had been observed a t the end of 7 2 hrs. when rubber connections were used. Repetition of these experiments with glass-sealed joints showed tha t this was not due t o faulty joints or action of the gases on the rubber.

Nov., 1 9 2 0 T H E JOL'RNAL O F 1,VDUSTRIAL

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 9 5 . 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 4 0 . 6 32 .9 3 0 . 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 4 6 . 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 s tudy of t he 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 s tudy of the intersolubility of dichloro- ethyl sulfide and ligroin a t various temperatures a re given in Table I and illustrated by the curve AA i n Fig. 2. The critical point of solubility, tha t 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.