Supported TiO2/MCM-41 as an efficient and eco-friendly catalyst for highly selective preparation of cyclohexanone oxime from solvent-free liquid phase oxidation of cyclohexylamine with molecular oxygen

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.…”

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

“…However, the CCA selectivity decreased gradually; this could be ascribed to the truth that CHA could easily condense with CH to CCA, and CCA could also be further oxidized to CHO and CH under present reaction parameters. Our previous works had verified the possible formation pathway of reaction products. − Therefore, the appropriate reaction parameters were achieved, namely, a temperature of 90 °C, an O 2 pressure of 1.0 MPa, a time of 5.0 h, and a catalyst dosage of 0.3 g. CHA conversion (59.8%) with 88.6% of CHO selectivity was achieved over the 0.1C-TiO 2 catalyst under optimum reaction conditions.…”

“…The catalyst-enriched surface hydroxyl groups exhibited a good catalytic activity for the selective oxidation of CHA to CHO in a solvent-free system. − , To further explore this catalytic oxidation process, some typical TiO 2 catalysts containing rich surface hydroxyl groups were screened, and the obtained results are summarized in Table . In reality, the oxidation reaction was not only without selectivity but also had poor reactivity in the absence of catalyst (entry 1).…”

“…Based on our previous work and the experimental results of this work, − the possible catalytic oxidation reaction pathway of CHA to CHO employing molecular oxygen as the oxidant over the C-TiO 2 catalyst is deduced in Scheme . First, CHA was activated by adsorption via the intermolecular hydrogen bond between the amine groups and surface hydroxyl groups of the catalyst, and the adsorbed intermediate was subsequently dehydrated to a transient species.…”

“…Recently, it had been proven that the catalyst-enriched hydroxyl groups on the surface exhibited good activity in the aerobic oxidation of CHA to CHO in our previous works. − Due to the rich surface properties of TiO 2 , it had been extensively applied in some oxidation reactions for preparing significant chemical intermediates. Almeida et al found that anatase TiO 2 exhibited good catalytic performance in the aerobic oxidation of cyclohexane to KA oil .…”