Modified zeolites as catalysts in the Friedel-Crafts acylation

Modified zeolites were found to be active catalysts in the Friedel-Crafts acylation of anisole by acetyl chloride and acetic anhydride. The effect of two different modifications of the zeolites were tested; lanthanum-exchange and varying the Si/Al ratio. For the rare-earth modified zeolites, the activity was found to be dependent on the lanthanum content, and the yield increased with the level of lanthanum even up to 93% exchange. Dealuminated Y-zeolites were also found to be very active, and an almost linear increase in the yield with decreasing aluminium fraction was found. This has been attributed to the increased hydrophobicity of dealuminated zeolites. Zeolite Beta was also found to be very active in the reaction.