Rapid Hydrolysis of p-Nitrophenyl Diphenyl Phosphate Catalyzed by o-Iodosobenzoate in Cationic Latexes

摘要

In aqueous dispersions of cationic polymer latexes containing 0.01-0.41 mg/mL ofparticles, 0.40-5.0 x 10 -5 M o-iodosobenzoate (IBA) catalyzes hydrolysis of 1.0 x 10 -5 M p-nitrophenyl diphenyl phosphate at 25 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 kIBA of 1.35 x 10 3 M-1s -1 exceeds by a factor of about 2 the maximum value reported by IBA in CTACI 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 chloromethylstyrenes, vinylbenzyltrimethylammonium 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.