Friedel−Crafts alkylation of diphenyl oxide with benzyl chloride over sulphated zirconia

Abstract

Friedel−Crafts reactions are ubiquitous in fine chemicals, intermediate, and petrochemical industries. In most of the cases very high yield and selectivities can be achieved with aluminium chloride as catalyst with nitrobenzene as a solvent. However, environmental concerns associated with aluminium chloride−nitrobenzene or BF₃−HF or mineral acids catalysts have encouraged process changes and the development of solid acid-based Friedel−Crafts reactions which are economically viable as well. This contribution deals with the alkylation of diphenyl oxide with benzyl chloride using sulphated zirconia as solid acid catalyst, which gives excellent conversions of the product benzyl-diphenyl oxide. The effects of a variety of parameters were studied in a batch reactor to establish the kinetics and mechanism of the reaction at 90 °C. The reaction obeys the Langmuir−Hinshelwood−Hougen−Watson mechanism involving weak adsorption of the reactants, and the reaction is intrinsically kinetically controlled.