Sartori The War Gases Chemistry and analysis

236 SULPHUR COMPOUNDS

while if the sulphur dichloride is in excess, sulphur monochloride, hydrochloric acid and a trichloro-derivative are formed :

With Hydriodic Acid. By the action of hydriodic acid in aqueous or acetic acid solution on dichloroethyl sulphide, both the chlorine atoms are substituted by iodine atoms and diiodoethyl sulphide is obtained (see p. 244).

Grignard's method for the detection of dichloroethyl sulphide depends on the reaction with sodium iodide (see p. 248).

With the Alkali Sulphides. Sodium and potassium sulphides react readily with dichloroethyl sulphide to form diethylene disulphide, also termed " dithiane."

CH2-CH

This forms white crystals with a melting point of 112° C., and has no toxic power. It boils at 115-6° C. at 60 mm. mercury pressure,1 and is volatile in steam. It is sparingly soluble in water, but readily in alcohol and ether. This compound, which was first obtained by Meyer 2 in 1886, is converted into the corresponding disulphone by treatment with hydrogen peroxide in acetic acid solution 3 :

/CH2-CH2\

02S< >S02

XCH2-CH/

Diethylene disulphide is also obtained, together with />-thioxane,

/CH2CH2X

S( >0

NCH2CH/

by distilling thiodiglycol with potassium bisulphate.4 It is also formed by the action of a saturated solution of hydrobromic acid in phenol on thiodiglycol.5

1J. JOHNSON, /. Chem. Soc., 1933, 1530.

2MEYER, Ber., 1886, 19, 3259.

3FROMM and UNGAR, Ber., 1923, 56, 2286.

4FROMM, Ber., 1923, 56, 2286.

*E. BELL and coll., /. Chem. Soc., 1927, 1803.

Sodium disulphide in aqueous solution reacts slowly with dichloroethyl sulphide, forming l :

S-CH2-CH2

SI—CH2-CH2

action of a 20% solution of potassium hydroxide in alcohol, dichloroethyl sulphide is converted into divinyl sulphide 2 :

CH=CH2

a mobile liquid with a characteristic odour which boils at 85° to 86° C. Its density at 15° C. is 0-9174. It readily polymerises, being transformed in less than a week into an opaque mass, soluble in carbon disulphide.3

Divinyl sulphide is also formed by the abstraction of two

boils at 58-5° C. at 15 mm. mercury and has a density of 1-1972 at 15° C. On treatment of divinyl sulphide in aqueous solution with hydriodic acid,6 /?/}' diiodoethyl sulphideis formed (see p. 244). With chlorine various chlorinated compounds are formed, for instance, a/J dichloroethyl vinyl sulphide :

/CHC1-CH2C1 S\NCH=CH2

and ocj3a'/3' tetrachloroethyl sulphide :

/CHC1-CH2C1

S

\XCHC1-CH2C1

Divinyl sulphide is formed quantitatively according to Helfrich 7 when dichloroethyl sulphide is treated with sodium ethylate.

•J. ALEXANDER and MCCOMBIE, /. Chem. Soc., 1931, 1913.

*HELFRICH and REID, /. Am. Chem. Soc., 1920, 42, 1219, 1224.

with alcoholic ammonia on heating to 60° C. under pressure, the reaction is vigorous 1 and 1-4 thiazane is formed as follows :

This is a colourless liquid with an odour of pyridine, boiling at 169° C. at 758 mm. of mercury. It fumes in the air and is miscible with water and with the common organic solvents. On exposure to the air it absorbs carbon dioxide.

With Aliphatic Amines. In presence of sodium carbonate, dichloroethyl sulphide reacts with the aliphatic amines in alcoholic solution as follows 2 :

in general colourless mobile oils with densities less than unity. The following are the principal :

4 Methyl 1-4 thiazane, b.p. 163° to 164° C. at 757 mm. Density 6-9959 at 15° C. Completely miscible with water and with various organic solvents.

on dichloroethyl sulphide dissolved in alcohol, dicyanoethyl sulphide is not formed, but a crystalline substance separates (m.p. 91° C.) of the formula C6H12S2(CN)2 which, later researches 3 have shown, has the structure

CN—CH2—CH2—S—CH2—CH2—S—CH2—CH2—CN.

Dicyanoethyl sulphide has been obtained, however, by boiling sodium sulphide with the nitrile of j3 chloropropionic acid, dissolved in alcohol :

CH2Cl-CH2CN + Na2S = 2NaCl

vesicatory properties.1

With Sodium Selenide. By boiling dichloroethyl sulphide with an aqueous solution of sodium selenide, 1-4 selenothiane is formed 2:

/CH2CH2\

S( >Se

NCH2CH/

This is obtained in thin colourless leaflets, melting at 107° C. It boils at a pressure of 97 mm. of mercury at 86-5° C., and behaves chemically in a similar manner to dithiane.

With Methyl Iodide. Dichloroethyl sulphide reacts with methyl or benzyl iodide, forming the corresponding sulphonium salt. For instance, with methyl iodide, dithiane methiodide is formed :

This is a crystalline substance melting at 174° C., easily soluble in hot water, soluble with difficulty in alcohol and insoluble in ether.3

With Magnesium Phenylarsine. By treating dichloroethyl sulphide in hot benzene solution with magnesium phenylarsine in ethereal solution, phenyl thioarsane is formed4:

4 mm. of mercury. It forms additive compounds with mercuric chloride.

Like the other cyclic sulphides, it has no vesicant action and only a weak toxicity.

With Zinc and Ethyl Alcohol. When an alcoholic solution of dichloroethyl sulphide is treated on the water-bath with zinc dust, a very complex reaction takes place and various compounds are formed : ethylene, hydrogen sulphide, hydrochloric acid,

1 NEKRASSOV, /. Rusk. Fis. Khim. Obsc., 1927, 59, 921.

dithiane, ethyl sulphide, vinyl ethyl sulphide, ethyl mercaptan, etc. The principal product is diethyl thioglycol 1:

/

H2CH2OC2HS

This is a liquid boiling at 225° C. at a pressure of 746 mm. Density 0-9672 at 20° C. It is volatile in steam, sparingly soluble in water, but soluble in the organic solvents. It has no vesicant power.

Various other condension products of dichloroethyl sulphide have been prepared, such as those with phenates, thiophenates, mercaptides and aromatic amines, and in every case the physical, chemical and biological properties of these have been studied.2 With Metallic Salts. Like various other organic sulphides, dichloroethyl sulphide readily reacts with the salts of the heavy metals. Thus with gold or platinum chloride, compounds are formed which, being insoluble in water, may be employed for the detection of the sulphide (see p. 248). With copper or mercury chloride stable additive chlorides are formed of the following

type:

[(C1CH2—CH2)2S]2 . Cu2Cl2.

These may be employed to determine dichloroethyl sulphide quantitatively (see p. 251). Tin and titanium chlorides similarly form additive products.3

Ferric chloride decomposes dichloroethyl sulphide, forming various halogenated vinyl compounds.4

With Metals. At ordinary temperatures the action of pure dichloroethyl sulphide on steel, iron, lead, aluminium, zinc and tin is practically nil. At higher temperatures, about 100° C., steel is slightly corroded, but aluminium and lead are not attacked (Gibson and Pope).

On warming in contact with iron, especially in presence of water, dichloroethyl sulphide is decomposed to form thiodiglycol, hydrogen sulphide, diethylene sulphide and its polymers, hydrochloric acid, hydrogen, ethylene and ethylene dichloride.

The action of crude dichloroethyl sulphide on the steel walls of projectiles has been studied by W. Felsing and H. Odeen.5 They have observed that in projectiles charged with dichloroethyl

242 SULPHUR COMPOUNDS

sulphide (prepared by Levinstein's method, see p. 223) the internal pressure increased on maintaining at 60° C. for 8 days to about 2 atmospheres. The degree of decomposition of' the sulphide was negligible, and the increase in acidity amounted to about i%.

The outstanding physiopathological property of dichloroethyl sulphide is its vesicant action. The first symptoms of this action appear after 4-6 hours, but sometimes the latent period may extend to 24 hours.

The sensitivity of the skin to dichloroethyl sulphide varies with the individual. Fair people are more sensitive than dark and the latter more sensitive than negroes.1

Exposure even for a short time (a few minutes) to a concentration of 0-2 mgm. of the vapours of dichloroethyl sulphide per cu. m. of air causes irritation, according to Gilchrist,2 without, however, visible lesions.

On contact of liquid dichloroethyl sulphide with the skin, erythema is produced with 0-12 mgm. per sq. cm. of skin and blisters with 0-5 mgm. per sq. cm. of skin.

On inhalation, according to American experiments,3 fatal

concentration of 70 mgm. per cu. m. of air.

Mortality-product: 1,500 according to both Miiller and Prentiss. For the decontamination of the skin, washing with hot soapy

water is very efficacious.4

For the decontamination of objects, Renwanz5 recommends the use of bleaching powder (see p. 231).

For the decontamination of glass materials, concentrated nitric acid mayvbe employed.6 This must be carried out with care because in the somewhat violent reaction liquid may be thrown out by the violent evolution of nitrous gases.

The decontamination of paper, print, documents, etc., may be carried out by exposing such objects to the action of gaseous ammonia in closed containers for several days.7

1 G. FERRI, " Ricerche sulla sensibilita individuale della cute umana all'iprite e sppra alcuni fattori capaci di modificarla" (" Researches on individual sensitivity of the human skin to mustard gas and on some factors which can modify this "), Giornale di Medicina Militate, September, 1937.

* GILCHRIST, The Residual Effects of Warfare Gases, II, U.S. Government Printing Office, Washington, 1933.

3PRENTISS, op. cit.

4S. PRZYCHOCKI, Heeressanitdtswesen, 1934, 23, 5, 6, Warsaw ; Gasschutz und

Luftschutz, 1936, 28.

j3]8' dibromoethyl sulphide was examined as a possible war gas only in the post-war period (Miiller). Although having similar physiopathological properties to dichloroethyl sulphide, it has some disadvantages as a war gas, especially from the manufacturing point of view (Hanslian).

Steinkopf 1 prepared dibromoethyl sulphide by the action of phosphorus tribromide on thiodiglycol. However, it may be prepared more simply by saturating an aqueous solution of thiodiglycol with hydrobromic acid.2

It may also be prepared, according to Kretov,3 by the action of hydrobromic acid or phosphorus tribromide on diethoxyethyl sulphide (see p. 238).

LABORATORY PREPARATION2

976 gm. thiodiglycol are dissolved in 400 ml. water in a flask fitted with a reflux condenser and a gas inlet-tube. It is cooled in ice and saturated with hydrobromic acid. The mixture is then heated to about 80° C. and more hydrobromic acid bubbled in until the reaction is complete. On cooling, the dibromoethyl sulphide solidifies, separating at the bottom of the flask. The aqueous layer is decanted off and the solid product washed with cold water and crystallised from ether. Yield 95%.

PHYSICAL AND CHEMICAL PROPERTIES

Dibromoethyl sulphide forms white crystals which melt at 31° to 34° C. (Steinkopf). It boils at ordinary pressure at 240° C. with decomposition and at i mm. pressure at 115-5° C.

The specific gravity at 15° C. is 2-05. It is insoluble in water and soluble in alcohol, ether and benzene.

The volatility at 20° C. is about 400 mgm. per cu. m. It is more rapidly decomposed by water than dichloroethyl sulphide.4

1 STEINKOPF, Ber., 1920, 53, ion.

Berlin, 1932, 84, in.

244 SULPHUR COMPOUNDS

On treating a hot solution of dibromoethyl sulphide in chloroform with benzoyl hydrogen peroxide, dibromoethyl sulphoxide is formed :

/CH2CH2Br OS(NCH2CH2Br

This forms glittering crystals melting at 100° to 101° C.1 It may also be' obtained by the action of concentrated nitric acid on dibromoethyl sulphide by first maintaining the temperature at o° C. and then allowing it to rise to room temperature to complete the reaction.2

Chromic anhydride and dilute sulphuric acid react at waterbath temperature with dibromoethyl sulphide to produce dibromoethyl sulphone 2 :

(/CH8CH2Br

which forms plates melting at 111° to 112° C.

Dibromoethyl sulphide, like the dichloro-compound, easily reacts with primary amines', forming the corresponding thiazane derivatives (Burrows).

It reacts with methyl iodide more readily than dichloroethyl sulphide, forming dithiane methiodide 3 :

/CH2CH2\ /CH3

W2CH/ S

The persistence of dibromoethyl sulphide on the ground is greater than that of dichloroethyl sulphide only in dry weather.

The physiopathological properties are similar to those of dichloroethyl sulphide according to Meyer,4 but milder.

orig—i^jri2i.

jSjS' diiodoethyl sulphide was not used as a war gas during the war of 1914-18, in spite of its great toxic power. It was obtained

1 LEWIN, /. prakt. Chem., 1930, 127, 77.

* A. MAYER, Compt. rend., 1920, 170, 1073.