Acylation of toluene with acetic anhydride over beta zeolites: Influence of reaction conditions and physicochemical properties of the catalyst

Acylation of toluene with acetic anhydride was carried out over Beta-type z eolites in a stainless steel autoclave. At low temperature, i.e., 150 degre es C, and an arene/anhydride molar ratio 10-20, high yields of 4-methylacet ophenone were obtained with selectivity close to 100%. The reaction is limi ted by the poisoning of the active sites by adsorption of the product and p ore blockage due to "coke"-type products. Acid site accessibility is of par amount importance for this reaction, and the use of a nanocrystalline Beta zeolite as catalyst minimizes catalyst decay. This, combined with an optimu m framework composition, allows the preparation of active and selective acy lation catalysts based on Beta zeolite. (C) 2000 Academic Press.