Immobilization of a block copolymer of styrene and quaternized 4‐vinylpyridine on latex and its effect on the cobaltphthalocyanine‐catalyzed oxidation of 2‐mercaptoethanol

To overcome mass transport limitations that are usually encountered on immobilizing highly active catalysts, cationic latex particles were used as support for tetrasodium phthalocyaninato‐cobalt(II)tetrasulfonate ( 2 ). The cationic. latex was prepared by emulsion copolymerization of styrene and divinylbenzene in the presence of a block copolymer from styrene and 4‐vinyl‐ N ‐methylpyridinium PS‐qPVP serving as surfactant. The latex‐bound system was found to considerably increase the reaction rate of the oxidation of 2‐mercaptoethanol in the presence of 2 as compared with the conventional polymer‐free system. Michaelis‐Menten kinetics was observed for all three systems investigated, that is the block copolymer‐stabilized latex system, the homogeneous block copolymer system and the quaternized 4‐vinylpyridine homogeneous homopolymer (qPVP) system. Although the stability of the latex and qPVP‐containing systems after successive runs is rather poor, this immobilization method shows the great potential value of anchoring highly active systems retaining high catalytic activity. The turnover number is increased on immobilizing the block copolymer compared with the homogeneous block copolymer solution. The Michaelis constant is hardly affected by immobilization. Due to conformational changes of the polymer chain on immobilization, a comparison between the latex system and the homogeneous system containing either homopolymer or block copolymer remains difficult.