Hydrolysis reactions nerve agents

Aminolysis of phenyl dithioacetates,8 pyridinolysis of O-ethyl dithiocarbonates,9 reaction of pyrrolidine with O-ethyl 5-aryl dithiocarbonates,10 aminolysis of chlorothionformates,11 pyridinolysis of alkyl aryl thioncarbonates,12 reaction of anionic nucleophiles with nitrophenyl benzoate and its sulfur analogues,36 hydrolysis of methyl benzoate and phenyl acetate containing SMe, SOMe and S02Me substituents,42 solvolysis of phenyl chlorothioformate,79 synthesis of new thiadiazoles,124 examination of a neighbouring sulfonium group in ester hydrolysis,136 hydrolysis of V-type nerve agents,250 and the reactions of peroxymonosulfate ion with phosphorus(V) esters have all been looked at previously in this review. 

These selected representative examples indicate that concentration-time profiles are variable despite common underlying basic chemical reactions of hydrolysis and adduct formation. Despite improving medical treatment of nerve agent poisoning the concurrence of numerous physiological and pathophysiological parameters should be understood. Therefore, establishment of a descriptive and predictive model is of importance for the medical defense of OP compounds. 

Many Binary Nerve Agent Components are corrosive or react with water to form corrosive materials. Components may also react with water to produce extremely toxic materials. Other common chemicals, such as alcohols, radiator fluids, dry cleaning solvents, or sulfur containing (vulcanized) products may react with components to form toxic materials. Reaction with dry bleach may produce toxic gases. In some cases, extremely hazardous decomposition products, some with toxicities near those of the original agents, are produced by hydrolysis of either the components or the Nerve Agents formed. 

Chemistry. The most extensively studied of VX s reactions are related to its decomposition (oxidation and hydrolysis) and this, in turn, may be related to its persistence. Hydrolysis occurs rather slowly (at pH 7 25°C 1/2 30 days) and its products, of which there are several, are pH dependent. Thus P-S bond cleavage predominates at pH < 6 or > 10, but P-0 cleavage is substantial in between. The former leads to 2-mercapto (A(A -diisopropyl)ethylamine, whereas the latter leads to 5-(2-diisopropylaminoethyl) methyl phosphonothioate (Munro et al., 1999). Because nerve agents may hydrolyze over time (Yang et al., 1992), they have been stabilized for storage by moisture removal (Henderson, 2002) ... 

Several reports exist on the effect of metal cations on satin hydrolysis (Wagner-Jauregg et al., 1955 Gustafson and Martell, 1962 Epstein and Mosher, 1968). Some of the metal ions that appear to be effective include Cu(ll), Au(ll), Ag(l), Ni(ll), and Zn(ll). The effect of hypochlorite on sarin decomposition has been studied (Epstein et al., 1956), including the effect of surfactant micelles on the process (Dubey et al., 2002). It was shown that the use of cetyltrimethylammonium bromide substantially increased the speed with which satin was destroyed by hypochlorite. The effect of surfactant on the oxidation of sarin (and other OPs) with o-iodosobenzoic acid has been examined (Hammond et al., 1989). As part of an extensive study of the reactivity of nerve agents, Larsson (1958a) conducted a study of hydrogen peroxide s reaction with sarin. 

Under environmental conditions, CWAs (vesicant agents, sulfur mustard (H, HD and HT) and lewisite (L) nerve agents, GA, GB, GD and VX) can undergo multiple-degradation processes such as hydrolysis, oxidation, dehydration and photolysis. These baseline degradation reactions can vary in rate and completeness, depending upon reaction temperature and pH, as well as the presence of free radicals and catalysts. Knowledge of these baseline reaction parameters has formed the basis for many modern decontamination procedures. 

The metabolism of nerve agents is dominated by hydrolysis. This occurs to a small extent by chemical reaction with water, but is predominantly mediated by... 

The destruction of acetylcholine by AChE is a very rapid reaction. Approximately 104 molecules of acetylcholine are hydrolyzed per second by a single AChE molecule. In contrast, hydrolysis of the nerve agent-AChE complex is much slower than hydrolysis of the acetylated enzyme that is produced by complexation with the normal substrate, ACh. The result is that the activity of AChE is inhibited for a prolonged period. 

In a study designed to produce monoclonal antibodies which would catalyse the hydrolysis of phosphorus nerve agents, Moriarty et al. used a synthetic strategy involving a monocyclic phosphorane as hapten for the production of a monoclonal catalytic antibody based on the T.S. for phosphonate hydrolysis. These haptens (18 and 19), which are effective catalysts for the hydrolysis of Soman [Bu MeCHOPMe(0)F], were generated from the reaction of (15) with the protected 3(S) aminoalcohols (16 and 17). ... 

Three types of chemical mechanisms have been used for decontamination water/soap wash oxidation and acid/base hydrolysis.9 Mustard (HD) and the persistent nerve agent VX contain sulfur molecules that are readily subject to oxidation reactions. VX and the other nerve agents (tabun [GA], sarin [GB], soman [GD], and GF) contain phosphorus groups that can be hydrolyzed. Therefore, most chemical decontaminants are designed to oxidize mustard and VX and to hydrolyze nerve agents (VX and the G series).1 Water and Water/Soap Wash... 

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