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 C3–C4 olefins (propene, isobutene and 1-butene). Although the catalytic performance depends on the nature of the olefin fed the TTB-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.