Polymer-supported sulfonimide as a novel water-tolerant Bronsted acid catalyst for esterification of equimolar carboxylic acids and alcohols

A novel polymer- supported sulfonimide (PS-SI), 10-(4'-perfluorobutylsulfonamino sulfonylphenyl)decylpolystyrene, was synthesized and characterized by FT-IR, solid state F-19 NMR, SEM and TGA. The acid strength determination indicated that PS-SI was a strongly acidic polymer. The catalytic performance of the polymer catalyst was tested by direct esterification of equimolar carboxylic acids and alcohols in excess water. The results showed that PS-SI was an effective Bronsted-acid catalyst and could be reused several times without any loss of catalytic activity. (c) 2006 Elsevier B.V. All rights reserved.