2-Chlorovinyl arsenous acid

Lewisite is too reactive to be analyzed by LC. Even with GC, it leads to a rapid degradation of column performance. Lewisites 1 and 2 initially hydrolyze to 2-chlorovinylarsonous acid (CVAA) (26) and bis(2-chlorovinyl)arsenous acid (28), respectively. LC/MS analysis of these trivalent acids is problematic, giving very poor signal-to-noise ratios in both... 

Chlorovinyl arsonous acid (CVA) 2-Chlorovinyl arsenous acid 2-Chloroethenyl arsonous acid Dihydroxy(2-Chlorovinyl)arsine 2-Chloroethenyl dihydroxyarsine C2H4AsC102 85090-33-1 Hydrolysis of Lewisite... 

There are very limited quantitative toxicokinetic data on L. Although there are no published estimates of the diffusion rates of L through the skin, observations from acute toxicity studies indicate that it penetrates rapidly. Studies of the kinetics of elimination of arsenic after subcutaneous injection of L in rabbits show that it is eliminated with a half life of 55-75 hours. The primary metabolite of L is 2-chlorovinyl-arsenous acid, which is formed by hydrolysis. This metabolite, like the parent compound, is able to bind to sulphydryl containing proteins. It is this property that is believed to be responsible for the toxicological effects of L, although no primary biochemical lesion has been identified. In rabbits the apparent volume of distribution... 

Nitric Acid. Chlorovinyl dichloroarsine, when treated with nitric acid, is oxidised to /3 chlorovinyl arsenic acid ... 

If concentrated nitric acid is employed, this oxidation is very violent and it is necessary to cool the reaction mixture. On the other hand, when dilute nitric acid is employed it is necessary to warm it in order to carry out the reaction. On standing, a colourless crystalline mass separates this is ]8 chlorovinyl arsenic acid which may be purified by recrystallisation from a... 

Hydrochloric acid and chlorovinyl arsenous oxide, a vesicant. The latter is a nonvolatile solid that is not readily washed away by rains. Strong alkalies destroy these blisterforming properties. 

Lewisite 1 per se is never found in the environment. Figure 18 shows that this compound hydrolyzes rapidly on contact with moisture to 2-chlorovinyl arsonous acid, which in turn slowly dehydrates to lewisite oxide (syn. 2-chlorovinyl arsenous oxide) (16). Both 2-chlorovinyl arsonous acid and lewisite oxide are nonvolatile. The most frequently used method for the identification of CWC-related chemicals is based on gas chromatography (GC) in combination with mass spectrometry (GC/MS). Indirect GC/MS analysis of lewisite 1 requires sample preparation, which involves conversion of lewisite oxide to 2-chlorovinyl arsonous acid in an acidic environment, followed by derivatization (12). The obtained species is both volatile and thermally stable, and thus amenable to GC analysis. Often, a mercaptan reagent is used as a derivatization agent. The reaction with 3,4-dimercaptotoluene is shown in Figure 19. 

Chlorovinyl arsenous oxide 2-Chlorovinyl arsenic oxide 2-Chlorovinyl arsine oxide 2-Chloroethenyl arsinic oxide Lewisite oxide C2H2AsC10 3088-37-7 Hydrolysis or dehydration of 2-chlorovinyl arsonous acid... 

Lewisite (a-lewisite or 2-chlorovinyl dichloroarsine) is only slightly soluble in water but when dissolved it hydrolyses rapidly into 2-chlorovinylarsine oxide. The oxide is fairly soluble in sea water. In an alkali solution a further reaction into acetylene and arsenic acid might be possible. With high turbulence, lewisite can dissolve more rapidly in large volumes of water. Because lewisite is 36 per cent arsenic by weight, even if broken down, a toxic element would always remain. 

Although Lewisite is only slightly soluble in water (0.5 g L j [123], hydrolysis is rapid and results in the formation of the water-soluble dihydroxy arsine (2-chlorovinyl arsonous acid). In basic solution, the traws-Lewisite isomer is cleaved by the hydroxyl ion to give acetylene and sodium arsenite this occurs even at low temperatures [79, 123]. ds-Lewisite must be heated to over 40°C to react with NaOH to yield vinyl chloride, sodium arsenite and acetylene. In aqueous solution, the ds-isomer undergoes a photoconversion into the tr zws-isomer. In water and in the presence of oxidizers naturally present in the environment, the toxic trivalent arsenic of Lewisite oxide is oxidized to the less toxic pentavalent arsenic [124]. Regardless of the degradation pathway, arsenical compounds will ultimately be formed. 

The effects of acute exposure to Lewisite degradation products are given in Table 2.10 [5]. When Lewisite 1 reacts with water, an arsenic based compound will form chlorovinyl arsonous acid (CVAA) and hydrochloric acid (HCl), see Equation 2.1 ... 

Lewisite [dichloro(2-chlorovinyl)arsine] is an organic arsenical known for its vesicant properties (Rosenblatt et al., 1975). It has a molecular weight of 207.32, vapor pressure of 0.58 mm HG at 25°C, a liquid density of 1,89 g/cm at 25°C, freezing point of -18°C, boiling point of 190°C, and is negligibly soluble in water (DA, 1974). The chemical structure of lewisite is shown below. Lewisite may occur as a trans-isomer and as a cis-isomer. In aqueous solutions, the cis-isomer undergoes photoconversion to the trans-isomer (Clark, 1989). hi the presence of moisture, lewisite is rapidly converted to the more stable but highly toxic lewisite oxide (2-chlorovinylarsenous acid) (Cameron et al., 1946). 

A solution of sodium bromate in dilute hydrochloric acid oxidises the arsenic trichloride and )8 chlorovinyl dichloroarsine to the pentavalent state. 

In the former reaction the main product is chloro(j3-chlorovinyl)methyl-arsine. In the latter triphenylarsine is produced in low yield together with traces of the compounds (CHCl=CH) AsCl3 and the remaining phenyl-arsines are produced in approximately equal amounts. The aluminum trichloride catalyst probably also helps the redistribution reactions (see Section II, A, 6,e). Long-chain acetylene derivatives also react with chloro-arsines in the same way 3,186), but complex products are obtained from tetrolic acid and arsenic trichloride 187). Hexafluorobut-2-yne does not react with arsenic trichloride although it does so with chlorodimethylarsine on heating or ultraviolet irradiation 188). 

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