Highly efficient Friedel-Crafts acylation of veratrole over TiO2-SnOx solid solution catalyst

Abstract

Friedel-Crafts (F-C) acylation reaction is one of the most effective processes to produce aromatic ketones. Classical homogeneous Lewis acid catalysts have difficulty in separation and solid waste generation, which limit their industrial application. Herein, binary metal oxide TiO2-SnOx were prepared, these solid solution catalysts show the highly efficient activity for the F-C reaction of veratrole and 4-chlorobenzoyl chloride (4-CBC). The optimized 0.1TiO2-SnOx catalyst exhibits the veratrole conversion of 74 % and the 4-chloro-3′,4′-dimethoxybenzophenone (CDMB) selectivity of 97 %. Additionally, it shows good stability. The outstanding catalytic performance of TiO2-SnOx can be attributed to homogeneous doping of Ti in SnOx at the atomic level, which results in the strong Lewis acid sites with high density on the surface of solid solution. This work revealed the superior Lewis acid catalyst with solid solution structure, constructed through binary metal oxide, can pave a new avenue for developing the solid Lewis acid with excellent catalytic performance.