Effects of structures of molybdenum catalysts on selectivity in gas-phase propylene oxidation

Unsaturated Penta-Coordinated Mo5c5+ Sites Enabled Low-Temperature Oxidation of C–H Bonds in Ethers

“…11 Factually, the mono-oxo and dioxo structures for molybdenum oxides can be modulated by temperature, gas-phase composition, and loading, 12 and also an appropriate arrangement of the molybdenum species interacting with the silica support significantly increases the epoxidation reactivity of propylene. 13 Based on robust ability of Mo-based catalysts for activation and bond breaking of C−H bond, their catalytic behaviors of the selective oxidation of methanol/DME to formaldehyde, methyl formate (MF), methylal, poly(oxymethylene) dimethyl ethers, 1,2-dimethoxyethane, etc. at low temperatures were evaluated, 2,14−16 and the oxidation of C−H bond in CH 3 O* intermediate was regarded as the rate-determining step.…”

“…Wang et al disclosed that the partly reduced species (Mo 5+ ) and the terminal oxygen atoms of MoO bonds actually act as active sites for the conversion of benzyl alcohols despite the oxygen-coordinated MoO6 octahedrons being present on the surface . Factually, the mono-oxo and dioxo structures for molybdenum oxides can be modulated by temperature, gas-phase composition, and loading, and also an appropriate arrangement of the molybdenum species interacting with the silica support significantly increases the epoxidation reactivity of propylene …”

“… 11 Factually, the mono-oxo and dioxo structures for molybdenum oxides can be modulated by temperature, gas-phase composition, and loading, 12 and also an appropriate arrangement of the molybdenum species interacting with the silica support significantly increases the epoxidation reactivity of propylene. 13 …”

Selective propylene epoxidation in liquid phase using highly dispersed Nb catalysts incorporated in mesoporous silicates

“…Metal incorporated mesoporous materials have shown promising features in the area of heterogeneous catalysis of olefin epoxidation due to their remarkable catalytic properties and relatively cheaper precursors compared with those for TS-1 catalyst preparation [50][51][52][53][54][55][56][57][58][59][60][61][62][63]. For example, Ti modified MWW zeolite shows N 99% selectivity to PO and 95% H 2 O 2 efficiency during propylene epoxidation [40,64].…”

A General Synthesis Strategy for Highly Dispersed Amorphous MoO3 over Supported Catalysts

“…Use of an silica-based support and MoO 2 (acac) 2 led to the formation of oligomolybdate and/or polymolybdate species when Mo content was below 12 wt.%. [19] Besides, MoO 2 Cl 2 was proposed to be a promising candidate, [24] however MoO 2 Cl 2 readily hydrolyzes to give MoO 3 in aqueous solution. To guarantee its stability, the solution pH should be quite low (pH < 1), which is detrimental to the physicochemical properties of support, especially for metal doped zeolites.…”