Arsine dichlorovinyl

Lewisite, dichloro(2-dichlorovinyl)arsine is a chemical that contains arsenic, which though a liquid is sufficiently volatile to be dispersed among enemy troops. The arsenic atom in the lewisite reacts with proteins and causes terrible blisters on the skin and damage to the eyes and lungs if inhaled. Fortunately, an antidote was devised as a result of the work of the British biochemist Rudolf Peters. The antidote was appropriately named British anti-lewisite (dimercaprol), and abbreviated to BAL. 

In general, arsenical compounds have an aggressive action when two of the three valences of the arsenic atom are linked to like atoms or groups and the third to a different atom or radicle. If all the three valences of the arsenic atom are linked to similar atoms or radicles the compound has practically no aggressive action. Thus in the series of chlorovinyl arsines, it has been found that trichlorovinyl arsine has practically no aggressive action compared with chlorovinylchloroarsine or dichlorovinyl chloroarsine ... 

Preparation of Chlorovinyl Dichloroarsine and Dichlorovinyl Chloroarsine from Trichlorovinyl Arsine 80 gm. trichlorovinyl arsine and 66-2 gm. arsenic trichloride are placed in a thick-walled glass tube which is then sealed in the flame. The tube is placed in an outer tube of steel, covered with asbestos, and the whole heated for 4 hours at 220° to 250° C. After allowing to cool, the glass tube is opened at the end and the oily contents distilled under reduced pressure. The products obtained are as follows ... 

They have high boiling points (190° to 260° C.), but on heating at ordinary pressure easily decompose. Chlorovinyl dichloroarsine is thus decomposed into dichlorovinyl chloroarsine and arsenic trichloride, dichlorovinyl chloroarsine into chlorovinyl dichloroarsine and acetylene, etc. This behaviour supports the belief that an equilibrium exists between the three chlorovinyl arsines and their components, acetylene and arsenic trichloride. The hypothesis is confirmed by the observation that from the reaction between acetylene and arsenic trichloride, it is not possible to produce any one of these compounds solely a mixture of all three is always obtained. 

When a 15% sodium hydroxide solution is employed at temperatures below 37° C., this decomposition takes place quantitatively, and only in the case of chlorovinyl dichloroarsine. This fact may be used for the quantitative determination of /3 chlorovinyl dichloroarsine in presence of dichlorovinyl chloro-arsine and trichlorovinyl arsine (Lewis). 

Hydrogen Peroxide. This arsine also is vigorously oxidised by hydrogen peroxide (Wieland). After evaporating the solution, dichlorovinyl chloroarsine remains as an oil which solidifies after... 

Potassium Cyanide. When an alcoholic solution of /3/S dichloro-vinyl arsine is treated with potassium cyanide, it is converted into /3/3 dichlorovinyl cyanoarsine, (ClCH=CH)2AsCN, which is a colourless oil with a high toxicity (Libermann). 

Chloramine-T. Treatment of dichlorovinyl chloroarsine with an equivalent amount of chloramine-T (CHa=C H4—S02Na=NCl) produces no additive-compound, unlike trichlorovinyl arsine. 

Moderate boiling with 15% sodium hydroxide causes the attack of both ]8 chlorovinyl dichloroarsine and dichlorovinyl chloroarsine, but not trichlorovinyl arsine, with formation of sodium arsenite which may be titrated with sodium bromate after acidification. 

Chlorovinyl arsines chlorovinyl dichloroarsine, dichlorovinyl chloroarsine and trichlorovinyl arsine and mixtures of these qv. It is interesting that several authors refer to the many varieties of lewisite. The chlorovinyl dichloroarsine variant qv is said to be typical. 

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