Catalysts Supported on Polymer Colloids

摘要

Polymer colloids containing tetraalkylphosphonium ions as phase transfer catalysts and cobalt ions as autoxidation catalysts have been prepared by emulsion polymerization and subsequent functional group transformations on the colloids. The 0.27 micrometer colloidal phase transfer catalysts are more active for reaction of cyanide ion with benzyl bromide than are the analogous 20 micrometer spherical bead catalysts, but the high electrolyte strengths used in phase transfer catalysis cause the colloids to coagulate. Cobalt phthalocyanine tetrasulfonate bound to ion exchange colloids catalyzes autoxidation of 2,6-di-t-butylphenol. Cobalt ions bound as carboxylic acid salts to poly(acrylic acid) and poly(methacrylic acid) copolymer latexes in the presence of amine ligands catalyze autoxidation of tetralin. Polymer colloids can be modified with catalytic groups just as macroscopic polymer particles can. Exposure to aqueous electrolytes and sometimes to organic solvents can cause the colloids to coagulate, but often they can be redispersed. Coagulation and filtration can be used to separate catalysts from aqueous reaction mixtures if necessary. Colloidal cobalt catalysts show promise of high activity for autoxidations of organic compounds in water. Reprints. (JES)