Oxidative dehydrogenation of alkanes over vanadium oxide prepared with V(t-BuO)3O and Si(OEt)4 in the presence of polyethyleneglycol

To obtain a higher concentration of isolated VOx species, VOx species incorporated into an SiO2-frame were first synthesized by the alkoxy-exchange reaction between metal alkoxides and polyethyleneglycol. After the calcination of the synthesized samples, they were characterized by N2 adsorption and Raman spectroscopy. The catalysts have mesopores and very high surface areas up to ca. 1000 m2/g, which can be controlled by the degree of polymerization of polyethyleneglycol. Oxidative dehydrogenation of propane using lattice oxygen of VOx incorporated into an SiO2-frame was carried out with a fix-bed flow reactor at 450 °C under atmospheric pressure. The catalytic activity of VOx incorporated into SiO2 was compared with that of VOx loaded onto SiO2 with similar VOx loadings. VOx incorporated into SiO2 showed higher selectivity to propylene than VOx loaded onto SiO2. The higher propylene selectivity could be ascribed to isolated VO43− species in the silica framework.