Preparation of cationic latexes with different length alkyl groups on their quaternary ammonium ions and their use as supports for IBA catalyst in the hydrolysis of PNPDPP

Abstract

In this study, four cationic latexes containing n-hexadecyl, n-octyl, or a methyl group as one of the alkyls on their quaternary ammonium ions were synthesized and used as supports for o-iodosobenzoate (IBA) catalyst in the hydrolysis of p-nitrophenyl diphenyl phosphate (PNPDPP). The quaternary ammonium ions of the latexes were utilized to bind IBA anion electrostatically. In the kinetics of the hydrolysis of PNPDPP, first-order rate constants ( k obsd) of the reaction were determined by varying the type of latex, its amount, and the concentration of IBA at pH 7.0, 8.0, and 9.0 at 25 °C. Thereafter, the second-order rate constants ( k cat) were calculated for some of the reactions. Changing one of the alkyl groups of the quaternary ammonium ions of the latexes in the order of methyl, n-octyl, and n-hexadecyl yielded higher catalytic activities. For the most active IBA/latex catalyst, k obsd and k cat values were determined to be 3.28 × 10 −2 s −1 and 652 M −1 s −1 at pH 9.0 and 25 °C for the PNPDPP hydrolysis, respectively.