Friedel-Crafts acylation using sulfated zirconia catalyst - Acylation of benzene with 4-chlorobenzoyl chloride over sulfated zirconia as catalyst

Synthesis of fine chemicals and intermediates by using Friedel-Crafts acyla tions is an important process in organic chemical technology. In most cases , very good yield and selectivity can be obtained with aluminium chloride a s catalyst in conjunction with nitrobenzene as solvent. However, with moder n environmental restrictions, in consonance with green chemistry, replaceme nt of aluminium chloride-nitrobenzene or BF3-HF with solid catalysts has gr eat industrial relevance. Acylation of benzene with 4-chlorobenzoyl chlorid e was attempted with different solid acid catalysts such as dodecatungstoph osphoric acid (DTPA), DTPA/K-10 clay, K-10, Amberlite, Amberlyst-15, Indion -130, Filtrol-24 clay, and sulfated zirconia. However, only sulfated zircon ia was found to be effective leading to 100% selective formation of 4-chlor obenzophenone, which is useful as an organic and pharmaceutical intermediat e; for instance, in the manufacture of Cytrazin-a well known drug. The kine tics of the reaction was studied to establish that the reaction obeys the L angmuir-Hinshelwood-Hougen-Watson mechanism with very weak adsorption of th e reactants. The reaction is intrinsically kinetically controlled.