Direct incorporation of vanadium into three-dimensional KIT-6: 2. Reactivity test for styrene oxidation

摘要

The direct incorporation of vanadium into the three-dimensional (3-D) cubic Ia3d mesostructure designated as V-KIT-6 was prepared, and the material obtained therein showed a very high specific surface area of～1,000 m_2/g with tunable pore diameters in a narrow distribution of sizes, ～5.7 to 6.0 nm. The coordination and nature of the V sites in V-KIT-6 were characterized by ~(51)V-spin-echo NMR analysis. It shows that after calcination, the V~(4+) species are totally oxidized to the V~(5+) state with 4- and 6-coordinated V-O environments in a highly dispersed state with much less crystalline V_2O_5 formation. The calcined V-KIT-6 materials showed excellent catalytic activity in the direct oxidation of styrene using tert-butyl hydroperoxide (TBHP) as an oxidant.