The Acetylation of Toluene and Benzene with Acetyl Chloride and Bromide and Acetic Anhydride Catalyzed by Calcined Iron Sulfate Activated by Exposure to a Mixture of Benzyl Chloride and the Aromatics

The acetylations of toluene and benzene with acetyl halides and acetic anhydride were studied over catalysts prepared by heat-treating FeSO4 in air, followed by activation on exposure to benzyl chloride in toluene or benzene at 40–80 °C for 1 h, together with FeCl3 and AlCl3. The sulfates treated at 700 and 800 °C showed high activity. The former, activated at 60 °C, gave 68% methylacetophenones, and the latter, more than 90%, with an isomer distribution of 2% ortho-, 1% meta-, and 97% para-form in the reaction of toluene with acetyl halides at room temperature, while the maximum yield was 24% with FeCl3 and 29% with AlCl3. A high yield of acetophenone, 77%, was obtained over the FeSO4 (700 °C) catalyst in the reaction of benzene with acetyl bromide at 60 °C for 1 h. The present catalysts were also highly active for the acetylation of toluene with acetic anhydride; e.g., 55% methylacetophenones were obtained over the FeSO4 (800 °C) catalyst at 100 °C for 5 h. FeCl3 and AlCl3 gave quite low yield compared with the present catalysts.