Catalytic performances of Mn–Ni mixed hydroxide catalysts in liquid-phase benzyl alcohol oxidation using molecular oxygen

• Published in: Applied catalysis. A, General Vol. 403; no. 1; pp. 136 - 141
• Main Authors: Tang, Qinghu, Wu, Chengming, Qiao, Ran, Chen, Yuanting, Yang, Yanhui
• Format: Journal Article
• Language: English
• Published: Kidlington Elsevier B.V 22.08.2011; Elsevier
• Subjects: Benzyl alcohol; Catalysis; Catalysts; Catalytic activity; Chemistry; Exact sciences and technology; General and physical chemistry; Hydroxides; Manganese; Mn–Ni mixed hydroxide catalyst; Molecular oxygen; Nickel; Oxidation; Theory of reactions, general kinetics. Catalysis. Nomenclature, chemical documentation, computer chemistry; Molecular oxygen; Oxidation; Benzyl alcohol; Mn–Ni mixed hydroxide catalyst; Hydroxides; Hydrogen; Segregation; Selectivity; Liquid phase; Solid solution; Specific activity; Characterization; Chemical reduction; Precipitation; Mn-Ni mixed hydroxide catalyst; Mixed catalyst; Crystalline phase; Oxygen; Catalytic reaction; Benzaldehyde; Aldehyde; X ray diffraction; Heterogeneous catalysis; Benzenic compound; Solid phase; Surface area; X ray absorption
• ISSN: 0926-860X; 1873-3875
• DOI: 10.1016/j.apcata.2011.06.023

[Display omitted] ► Mn–Ni mixed hydroxide catalyst is prepared by facile co-precipitation. ► A Mn-in-Ni(OH) 2 solid solution is formed and shows low reduction onset. ► The prepared catalyst is active in benzyl alcohol aerobic oxidation. ► Excess Mn results in segregated Mn 3O 4 phase with poor activity. ► The synergistic interactions exsit between Mn(III) and Ni(II) cations. Mn–Ni mixed hydroxide was synthesized by a facile co-precipitation method and the catalytic performance in the aerobic oxidation of benzyl alcohol using molecular oxygen was examined. The Mn/Ni molar ratio played an important role and the sample with Mn/Ni molar ratio of 6:4 showed the best catalytic activity. High specific activity of 8.9 mmol/(g h) along with the benzaldehyde selectivity of 99% was achieved at 100 °C within 1 h. Characterizations of X-ray diffraction, X-ray absorption and hydrogen temperature-programmed reduction suggested that co-precipitation method afforded the formation of Mn-in-Ni(OH) 2 solid solution without phase segregation. Excess amounts of Mn resulted in segregated Mn 3O 4 crystalline phase, which showed low surface area and poor catalytic activity. The synergistic interactions between Mn(III) and Ni(II) cations through oxygen bonding were suggested to enhance the activity of Mn–Ni mixed hydroxide catalysts for benzyl alcohol oxidation.