Cross-linked anion exchange latexes 20, 150, and 1200 nm in diameter were prepared via microemulsion, emulsion, and dispersion copolymerization, respectively, of vinylbenzyl chloride, styrene, and divinylbenzene followed by treatment with trimethylamine or tributylamine. As catalysts for the unimolecular decarboxylation of 6-nitrobenzisoxazole-1-carboxylate (1) the tributylammonium ion latexes were much more active than the trimethylammonium ion latexes. There were only small differences in the rates of decarboxylation in the three different tributylammonium ion latexes, and first-order kinetics were found at all relative concentrations of ion exchange sites and 1 in the 20 and 150 nm particle dispersions. Retardation of the rate both early and late in the reaction using a low concentration of the 1200 nm particles is attributed to slow mass transfer of 1 from solution to the particle surface and to competitive inhibition by the product ion.