Fresh and calcined supported 12-tungstosilicicacid: Synthesis, characterization and application to some acid catalyzed reactions

Abstract

A series of catalyst containing 20-70% of 12-tungstosilicicacid (TSA) supported onto neutral alumina (A) has been synthesized, characterized and evaluated for esterification of 1 degrees and 2 degrees alcohols. The best catalyst, TSA(3)/A (30% loading of 12-tungstosilicicacid onto neutral alumina) has been compared with TSA(3)/Z (30% loading of 12-tungstosilicicacid onto hydrous zirconia) in order to see the effect of nature of support. The catalytic activity of TSA(3)/A and TSA(3)/Z has also been explored for tert-butylation of phenol by varying different parameters. Both the catalysts were calcined in the temperature range of 300-500 degrees C and characterized by FT-IR, DRS and XRD to see the structural change in the calcined materials. Their catalytic activity was also evaluated for the esterification as well as tert-butylation of phenol under optimized conditions. An attempt has also been made to regenerate and to reuse the present catalysts, especially for tert-butylation of phenol. (c) 2007 Elsevier B.V .