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Peroxocarbonate ions HCO 4 − and CO 4 2− , which are formed in the H 2 O 2 /NH 4 HCO 3 /HO¯system, react with 4-nitrophenyl diethyl phosphonate (I) through a nucleophilic mechanism with rate constants k HCO 4 − = 0.008 and k CO 4 2− = 0.13 L/mol×s. Comparison of these constants with the corresponding constants of other inorganic anions in their reaction with I in the framework of the Brönsted equation indicates that HCO 4 − and CO 4 2− are typical a-nucleophiles. Key words: 4-nitrophenyl diethyl phosphonate, hydrogen peroxide, peroxyhydrocarbonate ion, peroxocarbonate ion, nucleophilicity.In addressing the outstanding problem of eliminating ecologically toxic substances, recent attention has been given to the reactivity of systems containing hydrogen peroxide and its activators, primarily, ammonium and alkali metal hydrocarbonates [1][2][3][4]. Such systems, which fully meet the requirements of green chemistry, are universal and may be used for the decomposition of highly toxic organophosphorus compounds and sulfide derivatives by an oxidative-nucleophilic mechanism since the HO 2 − anion, which is a powerful a-nucleophile [5, 6], and the HCO 4 − ion [1-4], which is an effective oxidizing agent, are both generated in the aqueous H 2 O 2 /HCO 3 − /HO -system. On the other hand, there have been a few reports that HCO 4 − and CO 4 2− ions formed in the H 2 O 2 /HCO 3 − system display nucleophilic properties [6][7][8]. In particular, in previous work [6], we noted that the HCO 4 − anion may act as a nucleophilic species in the decomposition of phosphates.In the present work, we carried out a detailed kinetic study of the decomposition of 4-nitrophenyl diethyl phosphonate (I), which is a model for several pesticides and chemical warfare agents, by the H 2 O 2 /NH 4 HCO 3 /HO -system and evaluated the nucleophilic reactivity of the HCO 4 − and CO 4 2− ions in aqueous solution. These studies may provide information for optimizing processes for the decomposition of ecologically toxic substances.

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