Mesoporous VMCM-41: highly efficient and remarkable catalyst for selective oxidation of cyclohexane to cyclohexanol

摘要: Liquid phase oxidation of cyclohexane was carried out under milder reaction conditions over mesoporous VMCM-41 molecular sieve catalysts using aqueous hydrogen peroxide as oxidant, acetic acid solvent, and methyl ethyl ketone initiator. The showed high substrate conversion excellent product (cyclohexanol) selectivity. Although the activity catalyst slightly decreased after first recycle, owing to leaching small amount non-framework vanadium ions, it, however, remained nearly same thereafter. This observation further confirmed by washing experiments where ions were removed upon ammonium acetate treatment. Further, washed also an similar that recycled catalyst. Thus, or behaves truly heterogeneous complemented both filtrate quenching studies. effects time, temperature, Si/V molar ratio, concentration on performance examined in order optimize selectivity cyclohexanol. However, use strong oxidizing agent, e.g., tertiary butyl hydroperoxide, resulted formation cyclohexanone major product. In addition, solvents like methanol, dioxan acetone lower activity.