Ethyl dichloroarsine

Dry methyl dichloroarsine does not attack iron or zinc (Prentiss). 

The lower limit of irritation is 2 mgm. per cu. m. of air (Muller). The maximum concentration which a normal man can breathe for a period not greater than i minute is 25 mgm. per cu. m. of air (Lustig). The lethal index is 3,000 according to Muller and 5,600 for 10 minutes exposure according to Prentiss. 

The vapours of these substances have a vesicatory action of the same type as that of dichloroethyl sulphide.  

Ethyl dichloroarsine was prepared by La Coste in 1881 by acting on mercury diethyl with arsenic trichloride  

It may also be obtained by heating ethyl arsine in a closed tube with mercuric, arsenic, antimony or stannous chloride.  

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Molecular weight (MW) is the value represented by the sum of the atomic weights of all the atoms in the molecule. For example, the MW of ethyl-dichloroarsine, C2HsAsC12, is as follows ... 

Ethyl dichloroarsine. Dichloromethyl ether Trichloromethyl chloroformate Chloropicrin... 

II /CHjCHjCl CHjCH2Cl Dichloroethyl sulphide CHaBr—COOC2H5 Ethyl bromoacetate C2H5—ASCI2 Ethyl dichloroarsine >-... 

Methyl dichloroarsine. Ethyl dichloroarsine. Chlorovinyl arsines. Phenyl dichloroarsine. Diphenyl chloroarsine. Diphenyl cyanoarsine. 

Of the ahphatic arsines, only ethyl dichloroarsine has been widely employed as a war gas and is considered as the typical substance for use in projectiles. Methyl dichloroarsine is classed by some German authors as a substance which was studied in the post-war period, but according to an American authority it was actually employed by the Allies towards the end of the war, though only in small quantity. ... 

Ethyl dichloroarsine was employed in March, 1918, by the Germans, being considered suitable for replacing dichloroethyl sulphide in offensive operations because of its immediate vesicant effect and its non-persistent character. 

In the laboratory, ethyl dichloroarsine may be obtained by the action of ethyl iodide on sodium arsenite by a method similar to that described already for the preparation of methyl dichloroarsine ... 

American Method. In America, a similar method was employed for the manufacture of ethyl dichloroarsine to that already described for methyl dichloroarsine. It consisted essentially in treating sodium arsenite with diethyl sulphate, then with diethyl sulphate, reducing the product obtained with sulphur dioxide and then chlorinating with hydrochloric acid. 

According to German claims, it is possible to obtain higher yields of ethyl dichloroarsine by this method than by the American method. 

Ethyl dichloroarsine is a mobile liquid with a characteristic odour which when highly diluted is reminiscent of fruit. It may be detected by this means at a concentration of 0-5 mgm. per cu. m. of air. It is colourless, becoming slightly yellow on exposure to air and light. It boils at ordinary pressure at 156° C. with decomposition, while at 50 mm. pressure it boils at 74° C.i and at II mm. pressure distils unchanged at 43-5° C. Its melting point is - 65° C. 

The specific gravity of ethyl dichloroarsine at 14° C. is 1 742, the coefficient of thermal expansion o ooii and the density of the vapour six times that of air. 

The volatility of ethyl dichloroarsine is lower than that of methyl dichloroarsine (Herbst) ... 

Nitric Acid. By prolonged heating of ethyl dichloroarsine with dilute nitric acid, acicular crystals of ethyl arsenic acid, melting at 95° to 96° C. (Dehn) or 99° to 100° C. (Backer) and soluble in water and alcohol, are formed. 

Hydrogen Peroxide, Like nitric acid, hydrogen peroxide converts ethyl dichloroarsine into ethyl arsenic acid (Backer) ... 

Sodium Iodide. Ethyl dichloroarsine reacts with sodium iodide in acetone solution to form ethyl diiodoarsine ... 

Hydrogen Sulphide. By the action of hydrogen Sulphide in aqueous or alcoholic solution on ethyl dichloroarsine, ethyl arsenious sulphide separates ... 

This reaction with hydrogen. sulphide may be used for the detection of small quantities (0-02-0-05 mgm.) of ethyl dichloroarsine (see p. 328). 

Calcium Hypochlorite. Ethyl dichloroarsine is easily decomposed by calcium hypochlorite, either solid or in aqueous suspension. Because of this property, chloride of lime is employed for the decontamination of objects contaminated with ethyl dichloroarsine. 

Ethyl dichloroarsine, when dry, does not attack iron even at a temperature of 50° C. It corrodes brass strongly, however. 

Detection of Ethyl Dichloroarsine When a solution of ethyl dichloroarsine is treated with an aqueous solution of mercurous nitrate, acidified with nitric acid, a white precipitate forms, and this changes to grey in a few seconds. 

Sensitivity a turbidity is easily visible in the presence of 2-5 mgm. ethyl dichloroarsine. 

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