Synthesis, characterization and catalytic activity of new solid acid catalysts, H3PW12O40 supported on to hydrous zirconia

New solid acid catalysts have been synthesized by comprising heteropolyacid (HPA) on to hydrous oxide. A series of catalysts containing 20-70% of 12-tungstophosphoric acid (PW) on to hydrous zirconia (Z) are synthesized. All resulting amorphous materials have been characterized by chemical analysis, chemical stability, ion exchange capacity, FTIR, TGA, surface area measurement and XRD. Catalytic activity of the materials have been evaluated for esterification of cyclohexanol to cyclohexyl acetate. The selected material was calcinated at 300 and 500 degreesC. The FTIR and DRS spectra of the materials were recorded to study the nature of the species present on the support. These studies indicate that the 12-tungstophosphoric acid keeps its Keggin-type structure unaltered up to 500 degreesC when supported on to hydrous zirconia. Based on the above experimental findings, catalytic performance was optimal with a loading of 30% of 12-tungstophosphoric acid on to hydrous zirconia. (C) 2002 Elsevier Science B.V. All rights reserved.