PROMOTED HYDROLYSIS OF SOME ORGANOPHOSPHATE ESTERS USING SUPPORTED [Cu(tmen)OH(OH)]+

Abstract

In this study, tetramethylethylenediamine copper(II) complex (Cu(tmen)Cl2) was synthesized and natural clay smectite and synthetic Dowex-50WX8resin containing Cu(tmen)(OH)(OH2)+ were prepared via ion exchange process in aqueous solution. Dowex- and smectite-supported Cu(tmen)(OH)(OH2)+ were used as a supported catalyst in the hydrolysis reactions of organophosphate compounds of diethyl-p-nitrophenyl phosphate and p-nitrophenyl diphenyl phosphate at different pH values. Scanning electron microscope attached with energy dispersive X-ray dedector and surface area analyzer were used for the characterization of the supported catalysts. The efficiency of these supported catalysts was evaluated in accordance with pseudo-first-order and Michaelis-Menten enzyme kinetic models. The amount of copper(II) complex in Dowex-supported catalyst was higher than that of smectite-supported one (1.36 mmol/g and 0.88 mmol/g, respectively) and the higher efficiency was obtained when Dowex-supported catalyst was employed in all of the hydrolysis reactions. 222 and 114-fold increasing in pseudo-first-order rate constants compared to the reactions without supported catalyst were observed for the hydrolysis of diethyl-p-nitrophenyl phosphate at pH 8.0 in the presence of Dowex-supported and smectite-supported catalysts.

In this study, tetramethylethylenediamine copper(II) complex (Cu(tmen)Cl2) was synthesized and natural clay smectite and synthetic Dowex-50WX8resin containing Cu(tmen)(OH)(OH2)+ were prepared via ion exchange process in aqueous solution. Dowex- and smectite-supported Cu(tmen)(OH)(OH2)+ were used as a supported catalyst in the hydrolysis reactions of organophosphate compounds of diethyl-p-nitrophenyl phosphate and p-nitrophenyl diphenyl phosphate at different pH values. Scanning electron microscope attached with energy dispersive X-ray dedector and surface area analyzer were used for the characterization of the supported catalysts. The efficiency of these supported catalysts was evaluated in accordance with pseudo-first-order and Michaelis-Menten enzyme kinetic models. The amount of copper(II) complex in Dowex-supported catalyst was higher than that of smectite-supported one (1.36 mmol/g and 0.88 mmol/g, respectively) and the higher efficiency was obtained when Dowex-supported catalyst was employed in all of the hydrolysis reactions. 222 and 114-fold increasing in pseudo-first-order rate constants compared to the reactions without supported catalyst were observed for the hydrolysis of diethyl-p-nitrophenyl phosphate at pH 8.0 in the presence of Dowex-supported and smectite-supported catalysts.