Hydrolysis of sarin

The calculated activation energy for the hydrolysis of sarin [43] on Amberlite-IRIOO is relatively low (22,000... 

The rate of hydrolysis of sarin on Dowex-50 cation exchange resin is insensitive to the stirring rate. However, with a more active catalyst (Amberlite-IRA 400), the rate constant at 20°C was 5.3, 7.5, and 8.5 h at 60,800 and 1000 revolutions/min , respectively, suggesting that film diffusion was the rate-limiting. step. Thus, the mechanism of the rate-limiting step depends on the nature of the catalyst [34]. 

A hydroxoaqua copper complex containing N, N, N, A -tetramethyl-1,2-diamino-ethane (250) is an excellent catalyst for the hydrolysis of sarin, O-isopropyl methylphosphonofluoridate (251), and diethyl p-nitrophenyl phosphate (252 R = Et). The mechanism of the reaction probably involves bound hydroxide attacking the phosphoryl group with concomitant electrophilic catalysis by copper. 

The second-order rate constant for the reaction between sarin and either 2-PAM I or II was found to be 170 L/mol per minute. If a phosphorylated or phosphonylated oxime that does not enter rapidly into the second step above is formed, that product may be an Inhibitor of cholinesterase. 7,88 Hydrolysis of sarin in the presence of 200-fold concentrations of V and II took place more rapidly in plasma from rats with the former oxime than with the... 

The results of this type of analysis are expressed in Table I for the catalytic effects of Cu(II) chelates on the hydrolysis of Sarin (8) and DFP (6,8),... 

Table I . Third-Order Rate Constants Assigned to 1 1 Cu(ll) Chelates as Catalysts in the Hydrolysis of Sarin and DFP at 25°...

Cohen, E.M., P.J. Christen, and E. Mobach. 1971. The Inactivation of Oximes of Sarin and Soman in Plasma from Various Species. I. The Influence of Diacetylmonoxime on the Hydrolysis of Sarin. Pp. 113-131 in Proceedings of the Koninklijke Nederlandse Akademie Van Wetenschappen, Series C, Biological and Medical Sciences, Vol. 74. J.A. Cohen Memorial issue. Amsterdam North-Holland. Davies, D.R., P. Holland, and M.J. Rumens. 1960. The relationship between the chemical structure and neurotoxicity of alkyl organophosphorus compounds. Br. J. Pharmacol. 15 271-278... 

Cohen, E.M., P.J. Christen and E. Mobach. 1971. The inactivation by oximes of Sarin and Soman in plasma from various species. I. The influence of diacetylmonoxime on the hydrolysis of Sarin. J.A. Cohen memorial issue. Nordi-Holland Pubhshing Company, Amsterdam. 

The reaction of sarin with hydrogen chloride has been reported and kinetics determined by NMR imaging (Bard et al., 1970). With rate constants determined at 25°C, 81.5°C, and 100°C, Arrhenius analysis led to a calculated activation energy of 17.8 kcal/mole. The base-induced hydrolysis of sarin analogs and tabun was studied by Larsson (1958b) and the half-life of GA has been estimated to be 1.5 min at pH = 11 at 25°C. Ultimately, and depending on conditions (pH, reaction times, and so forth), hydrolysis products may include fluoride ion (or hydrogen fluoride), the 1-methylethyl ester of methylphosphonic acid, methylphosphonic acid, and 2-propanol. 

Cohen The study of the effects of stereo-isomers is of great importance to pharmacology. You were quite right in stressing the fact that pure enantiomers should be used. Another important point is that one should be sure that no racemization in vivo occurs. Working with sarin we had difficulty in avoiding this pitfall since racemization of this compound is catalysed by fluoride ions which arise from the hydrolysis of sarin by sarinase in rat blood plasma. 

Cohen, E. M Christen, P. J., and Mobach, E. (1971). The inactivation by oximes of. sarin and soman in plasma from -various species 1. The influence nf diaeety I monoxime on the hydrolysis of sarin, In J.A. Cohen Memorial Issue Proc. K. Ned. Wet. C.. pp. 113-131. North-Holland, Amsterdam. 

We do not consider the toxicity of hydrolysis products, thus underestimating the danger. For example, in the hydrolysis of sarin, several compounds are formed, and among them only one can be considered non-toxic. In the case of yperite, hydrolysis products are also highly toxic, and, as for lewisite, oxide produced in hydrolysis is equally dangerous. 

STABILIZER. A substance that prevents or retards the degradation of a chemical warfare (CW) agent and, thus, stabilizes it. Many CW agents are inherently unstable or are contaminated with by-products as a result of the production process. Such degradation limits the shelf life of the agents and detracts from the use of these agents for military purposes. For example, tributylamine is one of several stabilizers that can be added to slow or prevent hydrolysis of sarin in storage. 

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