Heteropoly tungstate supported on tin oxide catalysts for liquid phase benzylation of anisole with benzyl alcohol Original Research Article

A series of 12-tungstophosphoric acid supported on tin oxide catalysts were prepared and characterized by FT-Infra red, X-ray diffraction, Laser Raman spectroscopy and temperature programmed desorption of ammonia. The characterization results suggest the presence of Keggin ions and the generation of strong acidic sites on the support. The catalysts were evaluated for benzylation of anisole with benzyl alcohol as benzylating agent. The benzylation activity depends on the content of TPA on tin oxide; the catalyst with 15 wt% loading of tungstophosphoric acid showed highest activity. The structural and surface modifications and their influence on benzylation activities were studied by treating the catalysts at different calcination temperatures. The benzylation activity varied with the change in stability of the Keggin ion structure, which depended upon treatment conditions. The alcohol conversion and selectivity were also dependent on the anisole-to-benzyl alcohol ratio, reaction temperature, reaction time and catalyst weight.