Zeolite-catalysed acetylation of alkenes with acetic anhydride

Among various microporous adsorbents such as alumina, silica, clays, mol. sieves, etc., the HY zeolite was found to be best at promoting the acylation of 2,3-dimethyl-2-butene with acetic anhydride. The influence of numerous exptl. parameters on the course of the reaction was investigated. Variations in the silica/alumina ratio of the zeolite, or in the relative proportions of reagents and catalyst, markedly affected the yield of 3,3,4-trimethyl-4-penten-2-one, whereas the reaction time and temp. were less influential. The procedure was extended to various other alkenes and it was possible to regenerate and to reuse the solid catalyst without significant loss of activity