RAPID HYDROLYSIS OF PARA-NITROPHENYL DIPHENYL PHOSPHATE CATALYZED BY ORTHO-IODOSOBENZOATE IN CATIONIC LATEXES

In aqueous dispersions of cationic polymer latexes containing 0.01-0.41 mg/mL of particles, (0.40-5.0) X 10(-5) M omicron-iodosobenzoate (IBA) catalyzes hydrolysis of 1.0 x 10(-5) M p-nitrophenyl diphenyl phosphate at 25-degrees-C and pH 8.0 with a pseudo-first-order rate constant of up to 0.064 s-1. The highest second-order rate constant k(IBA) of 1.35 x 10(3) M-1 s-1 exceeds by a factor of about 2 the maximum value reported for IBA in CTACl micelles, the previous fastest medium for IBA-catalyzed hydrolysis of phosphate esters. The most active latexes are swollen 2.4-10 times their dry volume in water. The 150 nm diameter ion exchange latexes were prepared by emulsion copolymerization of (chloromethyl)styrenes, (vinylbenzyl)-trimethylammonium chloride, divinylbenzene, and styrene and characterized by transmission electron microscopy and dynamic light scattering. Reaction of the chloromethyl groups with trimethylamine created ion exchange latexes with quaternary ammonium groups inside as well as on the surface of the particles.