Oxidative dehydrogenation of cyclohexane with Mg_3(VO_4)_2 synthesized by the citrate process

摘要

Citric acid complexation under mild condition was proposed to prepare monophasic and well crystallized Mg3(VO_4)_2 particle to be used as an active catalyst for the oxidative dehydrogenation of cyclohexane to cyclohexene. The catalyst prepared above was characterized by N_2-physisorption. X-ray diffraction, scanning electron microscopy, and thermal gravimetric analysis. The characterization results displayed that the Mg_3 (VO_4)_2 particle was typically 100-160 nm and the specific surface area was 12.0-26.7 m~2/g. Moreover, it showed that the purity and the structure of the catalyst were principally subjected to the calcination temperature and the amount of citric acid used in the sol-gel procedure. The Mg_3(VO_4)_2 catalyst calcined at 823 K for 6 h with a molar ratio of (Mg + V):citric acid = 1:1.2 exhibited the best catalytic performance with an excellent thermal stability.