Selective oxidation of C3-C4 olefins over Mo-containing catalysts with tetragonal tungsten bronze structure

Mo-V-Nb-P-O-based catalysts with a tetragonal tungsten bronze-type (TTB) structure have been prepared hydrothemally from a H3PMo12O40 Keggin-type heteropolyacid. These catalysts have been tested in the oxidation of C-3-C-4 olefins (propene, isobutene and 1-butene). Although the catalytic performance depends on the nature of the olefin fed the TrB-type catalysts prepared in the presence of elements of the V and VI groups such as Te, Sb and Bi have shown a high selectivity to partial oxidation products, especially that with Te. However, in the absence of these elements the TTB-catalysts present a high catalytic activity to deep oxidation. The selectivity to partial oxidation products decreases in the order: MoVNbPTe- > MoVNbPSb- > MoVNbPBi- > MoVNbP-TTB catalysts. The reaction products obtained in the oxidation of each olefin will be discussed according to their corresponding reaction mechanism and the characteristics of catalysts. (C) 2008 Elsevier B.V. All rights reserved.