Alkylation of benzene catalysed by supported heteropolyacids

A new kind of solid acid based on heteropolyacids has been proved to be a useful catalyst in alkylation of benzene with propylene to obtain cumene. The new catalysts are based on a heteropolyacid supported on zirconia treated with very low contents of sulphate anions. Two different heteropolyacids have been studied, both with Keggin structure, (H3PMo12O40, H3PW12O40), and both produced active catalysts. The zirconia was used either pure or doped with few percent of iron oxide. The catalysts have been characterised through XRD, P-31 NMR and HREM. These catalysts are very active in alkylation reaction even at mild temperature. Their two outstanding features are the low n-propylbenzene production and th possibility to regenerate it at moderate temperature (350 degrees C). The best catalyst is based on H3PW12O40, supported on zirconia doped with iron and treated with sulphate ions. (C) 1999 Elsevier Science B.V. All rights reserved.