Highly Selective Preparation of Cyclohexanone Oxime from Liquid-Phase Catalytic Oxidation of Cyclohexylamine with Molecular Oxygen over Glucose-Modified TiO₂ under Solvent-Free Conditions

Abstract

A simple and highly efficient method for manufacturing cyclohexanone oxime from solvent-free liquid-phase aerobic oxidation of cyclohexylamine over a glucose-modified TiO 2 catalyst had been developed under mild reaction conditions. The results indicated that glucose-modified TiO 2 -enriched surface hydroxyl groups as an efficient catalyst played a crucial role in activating cyclohexylamine, and 59.8% conversion and 88.6% selectivity to cyclohexanone oxime were achieved. The characterization results by Brunauer−Emmett−Teller (BET), X-ray diffraction (XRD), and X-ray photoelectron spectroscopy (XPS) techniques indicated that the introduction of glucose effectively improved the surface areas, and the amounts of surface hydroxyl groups of the catalyst and the new C−O−Ti bonds were formed. Finally, combined with the experimental results, the possible catalytic oxidation pathway over the glucose-modified TiO 2 catalyst was deduced. This work employing inexpensive and highly reactive glucose-modified TiO 2 as the catalyst and molecular oxygen as the oxidizer for preparing cyclohexanone oxime from aerobic oxidation of cyclohexylamine is promising and has extensive prospects in industrial applications.

Solvent-free liquid-phase selective catalytic oxidation of toluene to benzyl alcohol and benzaldehyde over CeO2–MnOx composite oxides

“…To date, few research studies on Ce-Mn composite oxides have been reported in solvent-free liquid-phase selective catalytic aerobic oxidation of toluene. Based on this concept and our previous studies of the oxidation reaction, [32][33][34][35][36] a simple and environmentally friendly approach for selective preparation of BAL and BOL from the liquid-phase aerobic oxidation of toluene in a solvent-free system has been successfully developed employing CeO 2 -MnO x composite oxides as an efficient and cheap catalyst. The obtained results from the catalytic aerobic oxidation process of toluene will be reported in detail in the present work.…”