Diphenyl chloroarsine

Compound (XVI) was best considered as a straight derivative of phosphine and not derived from the acid. Compare diphenyl chloroarsine. 

It will be seen from this table that the lower limit of irritation of the war gases may vary between fairly wide limits. The substance with the greatest irritant power known to the present is diphenyl chloroarsine. 

The substance having the lowest limit of insupportability is diphenyl chloroarsine, and that having the highest is chloropicrin. 

As is seen from Table VI, the values vary over a wide range while diphenyl chloroarsine at 20° C. has a volatility of only 0-68 mgm. per cu. m. of air, at the same temperature the volatility of chloropicrin is 184,000 mgm. per cu. m. of air. Because of these differences in volatility, the various war gases are used for different types of objective and applied by different methods. 

This law is not, however, always applicable. With some substances, as dichloroethyl sulphide, diphenyl chloroarsine, etc., it is found that the introduction of further halogen atoms first diminishes and then destroys the aggressive properties of the original compound. 

In the series of aromatic arsines there is a great difference in aggressive action between triphenyl arsine, phenyl dichloroarsine and diphenyl chloroarsine. 

CgH5)2AsCl Diphenyl chloroarsine Limit of insupportability, I mgm./cu. m. 

The presence of halogen atoms in the molecules of organic arsenicals usually confers irritant properties. Among these halogen compounds, those containing chlorine have a superior irritant power to the analogous bromine and iodine compounds, e.g., diphenyl chloroarsine has a greater irritant power than diphenyl iodoarsine. 

An increase in toxic power is also found in organic compounds whose molecules contain a cyanide radicle thus diphenyl cyanoarsine is more irritant than diphenyl chloroarsine ... 

Solid. Diphenyl chloroarsine, diphenyl cyanoarsine, chloroacetophenone, etc. 

Blue Cross Gases. This includes solid substances with low volatility and great irritant power diphenyl chloroarsine, diphenyl cyanoarsine, etc. 

It combines with hydrogen under the influence of light and heat, and reacts energetically with most of the non-metals forming the respective chlorides. By this method arsenic trichloride may be prepared and this is employed in the preparation of the chlorovinyl arsines (Perkins s method) and diphenyl chloroarsine (Michaelis s method). Sulphur chloride is prepared similarly, and this is employed in the preparation of dichloroethyl sulphide by Guthrie s method. 

These compounds form an important group of war gases. They were employed alone and also mixed with other war gases phosgene, chloropicrin, diphenyl-chloroarsine, etc. 

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

Of these, the aromatic arsines were very largely used during the war, especially diphenyl chloroarsine. The aggressive action of these aromatic arsines, unlike that of all the compounds... 

During the war much diphenyl chloroarsine was employed. However, in May, 1918, it was largely substituted by diphenyl cyanoarsine by the Germans because of the superior physio-pathological effects of the latter. Diphenyl cyanoarsine is considered as the most irritant substance employed during the war. 

Since the war several other substances similar to diphenyl chloroarsine have been the subjects of experiments. For instance. 

Diphenyl Arsine. By the action of diphenyl arsine on phenyl dichloroarsine, arsenobenzene and diphenyl chloroarsine are formed ... 

Phenyl dichloroarsine was employed during the war of 1914-18 first by the Germans as a solvent for diphenyl cyanoarsine and later by the French in admixture with 40% of diphenyl chloroarsine under the name of Sternite. ... 

Diphenyl chloroarsine was prepared in 1880 by La Coste and Michaehs by heating mercury diphenyl with phenyl dichloroarsine ... 

During the war the Allies, in order to obtain rapid production of diphenyl chloroarsine, followed the method of Michaelis, modified by Morgan and Vining. This method consists in preparing triphenyl arsine from chlorobenzene and arsenic trichloride, in the presence of metallic sodium ... 

The preparation of diphenyl chloroarsine in the laboratory is most conveniently carried out by Pope and Turner s modification of the method of Michaelis. 

The Allied Method. The manufacture of diphenyl chloroarsine by the Allies, as indicated above, consisted of two main stages ... 

The conversion of the triphenyl arsine into diphenyl chloroarsine. 

First fraction, 150° to 190° C., consists of a mixture of phenyl dichloroarsine and diphenyl chloroarsine. 

Third fraction, 220° to 250° C., cbnsists of triphenyl arsine and diphenyl chloroarsine. 

The residue consists chiefly of triphenyl arsine, which is extracted with chloroform and treated, after evaporating off the solvent, with phenyl dichloroarsine in an autoclave. About 60% of diphenyl chloroarsine is thus obtained. 

The yield of diphenyl chloroarsine by this method, which has the advantage of being carried out at ordinary pressure instead of in an autoclave, as is necessary in Morgan s method, depends predominantly on the time employed in adding the arsenic trichloride. 

The English and French, employing the method of Michaelis, modified by Pope and Turner, succeeded in obtaining a mixture containing 60-65% diphenyl chloroarsine and 35-40% phenyl dichloroarsine, which was employed without further treatment. 

The mixture is stirred continuously and maintained for 3 hours at 15° C., when sodium phenyl arsenate is formed. This is neutralised with hydrochloric acid and filtered through a press in order to separate resinous substances which are formed. The phenyl arsenic acid in the filtrate is reduced to phenyl arsenious oxide by passing a current of sulphur dioxide through. A heavy oil deposits at the bottom of the vessel and this is removed by decantation and redissolved in 40° B. sodium hydroxide solution. After diluting with 8 cu. m. of water, the solution is cooled to 15° C. and run slowly into another solution of diazobenzene chloride prepared as before. The sodium salt of diphenyl arsenic acid which is formed is slightly acidified with hydrochloric acid, the diphenyl arsenic acid filtered off and redissolved in 20° B6. hydrochloric acid (i part of the arsenic acid requires 3 parts of hydrochloric acid) and the solution obtained is then run into an iron vessel, lined internally with tiles. Sulphur dioxide is then passed through for 8 hours while the temperature is maintained at about 80° C. Diphenyl chloroarsine then separates as an oil which forms a layer at the bottom of the vessel. It is separated off and dried in vacuo. 

Crude diphenyl chloroarsine is a dark brown liquid which gradually turns into a semi-solid viscous mass. 

In the pure state diphenyl chloroarsine forms colourless crystals which melt at 41° C. According to some authors it exists in two crystalline modifications, the stable one melting at 387° to 38-9° C. and the labile at 18-2° to 18-4° C. The labile modification is easily converted into the stable form. ... 

Somewhat differing values are reported in the literature for the melting point of diphenyl chloroarsine ... 

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