Mo-functionalized MCF meso-material and its catalytic performance for epoxidation of propylene by cumene hydroperoxide

The Mo-containing MCF (Mo-MCF) material was synthesized hydrothermally and used to catalyze the epoxidation of propylene with cumene hydroperoxide (CHP). The structure properties of the catalyst and the structure of surface molybdenum species were characterized by BET, TEM, XRD, Raman and UV–vis spectroscopies. It has been shown that, the Mo-MCF material has the meso-structure of silica MCF after introduction of molybdenum, and there are three molybdenum species of the isolated molybdenum species, polymolybdate species and little crystalline MoO3 of <5 nm existed in the MCF support, among which isolated and poly-molybdenum species are responsible for an increase of the epoxidation selectivity. The distribution of the molybdenum species is obviously affected by the preparation process. On the MoO3/MCF catalyst prepared by an impregnation, more polymolybdate species would congregate into dense MoO3, resulting in a decrease of the epoxidation selectivity. Comparatively, HMS, SBA-15 and SiO2 support were used to study the effect of the textural properties on the catalytic performance of Mo-containing catalyst. The results show that the structure character of support is another important factor to influence the catalytic performance of the catalyst, and the Mo-MCF material having the structure that is favorable for CHP molecules to access the active Mo sites, would restrain the decomposition of CHP and help to increase the epoxidation selectivity.