Polymers as Reagents and Catalysts. Part 28. the Effect of Polymer Catalyst Structure on the Esterification of Acids

Abstract

Crosslinked sulphonated polystyrene (Dowex 20 M) and various salts of crosslinked co-poly[styrene-4-vinylpyridine] with hydrogen halides were used as solid catalysts in investigations of the conversion of acids to esters. The role of the structure of the acid (acetic acid, benzoic acid), solvent (n-octane, toluene, n-butanol) and reaction temperature in the presence of polymer supported catalyst was tested in the reaction with n-butanol. Sulphonated crosslinked polystyrene (3a) was the most active catalyst, similar activity was found with crosslinked co-poly[styrene-4-vinyl(pyridinium chloride)], while catalysts bearing a fluoride (3b) and iodide (3e) function were almost unreactive. The important role of cosolvents was also established.