N-Butane oxidative dehydrogenation over VO X-HMS catalyst

Abstract

The demand for olefins increases in recent years. Oxidative dehydrogenation (ODH) of n-butane is possible alternative to classical dehydrogenation, steam cracking and fluid catalytic cracking processes. The role of particular VO X species supported on hexagonal mesoporous silica (HMS) in oxidative dehydrogenation (ODH) of n-butane was investigated on two sets of VO X -HMS catalysts prepared by wet impregnation and direct synthesis differing in amount and distribution of VO X species. The materials were characterized by XRF, N 2-BET isotherms, XRD, SEM, H 2-TPR, O 2-TPO and DR UV–vis spectroscopy and tested in ODH of n-butane in the range of temperature from 460 to 540 °C. The highest activity and selectivity to olefins were reached on materials with high content of isolated monomeric VO X units with tetrahedral coordination which are generated up to 4–5 wt.% of vanadium. The species with high degree of polymerization participate mainly on total oxidation reactions and those species are formed especially by wet impregnation.