Preparation of polymer supported catalysts for organophosphate ester hydrolysis and investigation of hydrolysis kinetics

iiABSTRACTPh.D DissertationPREPARATION OF POLYMER SUPPORTED CATALYSTS FORORGANOPHOSPHATE ESTER HYDROLYSIS AND INVESTIGATIONOF HYDROLYSIS KINETICSMurat ERDEMAnadolu UniversityGraduate School of SciencesChemistry ProgramSupervisor: Prof. Dr. Hayrettin TÜRK2006, 178 pagesIn this study, the hydrolysis of organophosphate ester compounds paraoxon(PO) and p-nitrophenyl diphenyl phosphate (PNPDPP) catalyzed by o-iodosobenzoate (IBA) bound to resin or latex supports were investigated. For thispurpose, resins and latexes which can bind IBA to their quaternary ammoniumgroups electrostatically were synthesized and their IBA binding capacities weredetermined. The synthesized resins supports contain n-hexadecyl group on theirquaternary ammonium groups whereas the latexes contain n-hexadecyl, n-octyl,or methyl group on their quaternary ammonium groups.In the hydrolysis experiments, at pH 7.0, 8.0, and 9.0, kobserved rate constantswere determined for the hydrolysis of PO and PNPDPP catalyzed by IBA boundto resins and latexes at different IBA concentrations and thereafter, kcat rateconstants were calculated from the slopes of [IBA]-kobserved graphics. Also, thehydrolysis of PO with IBA in n-hexadecyltrimethylammonium bromidecontaining medium was investigated. Because the variations in thehydrophobic/hydrophilic characters of resins, their IBA binding capacities, type ofcross-linking agent, ratio of functional monomers, and the equivalent number ofquaternary ammonium groups in the resins gave different activities for thehydrolysis of the substrates. At pH 9.0, kobserved and kcat were determined for themost active IBA/resin catalyst as 1.03x10-4 s-1 and 0.18 M-1s-1 for PO hydrolysis,respectively and 2.20x10-3 s-1 and 3.89 M-1s-1 for PNPDPP hydrolysis,respectively. In latex bound IBA catalysis, changing one of the alkyl groups of thequaternary ammonium group in the latexes the order of methyl, n-octyl and n-hexadecyl yielded higher catalytic activities for the hydrolysis of PO andPNPDPP. At pH 9.0, kobserved and kcat were determined for the most activeIBA/latex catalyst as 2.71x10-4 s-1 and 5.29 M-1s-1 for PO hydrolysis, respectivelyand 3.28x10-2 s-1 and 651.7 M-1s-1 for PNPDPP hydrolysis, respectively.Keywords: Organophosphate Ester, o-Iodosobenzoic Acid, IBA, Resin, Latex,Paraoxon, p-Nitrophenyl Diphenyl Phosphate