Oxidative Carbonylation of Methanol to Dimethyl Carbonate Over Cu(Ⅱ)-1, 10-Phenanthroline Bromide Complexes

doi:10.1016/j.cjche.2014.08.005

Abstract

Abstract: In order to develop the catalysts with low corrosiveness for the oxidative carbonylation of methanol to dimethyl carbonate (DMC), CuBr₂ was selected as the metal source to prepare Cu coordination compounds, Cu(phen)Br₂, [Cu(phen)₂Br]Br and [Cu(phen)₃]Br₂ (phen = 1,10-phenanthroline). These complexes were characterized by thermogravimetric analysis and temperature-programmed reduction. Their catalytic performances were investigated. It was found that the metal coordination environments and thermal stability of the complexes played an important role in their catalytic activities. Cu(phen)Br₂ exhibited the highest activity due to the lowest steric hindrance, themost positions occupied by the bromide ions and the highest thermal stability. The turnover number was up to 47.6 DMC mol·(Cumol)^-1 with selectivity of 92.8% under conditions of 120 ℃, ratio of partial pressure of CO to O₂ of 19:1 (below the explosion limit of CO) and catalyst concentration of 0.011 mol·L^-1. Furthermore, a plausible reaction mechanism was suggested on the basis of the experimental data.

Key words: Dimethyl carbonate, Cu(phen)Br₂, Methanol, Oxidative carbonylation

摘要： In order to develop the catalysts with low corrosiveness for the oxidative carbonylation of methanol to dimethyl carbonate (DMC), CuBr₂ was selected as the metal source to prepare Cu coordination compounds, Cu(phen)Br₂, [Cu(phen)₂Br]Br and [Cu(phen)₃]Br₂ (phen = 1,10-phenanthroline). These complexes were characterized by thermogravimetric analysis and temperature-programmed reduction. Their catalytic performances were investigated. It was found that the metal coordination environments and thermal stability of the complexes played an important role in their catalytic activities. Cu(phen)Br₂ exhibited the highest activity due to the lowest steric hindrance, themost positions occupied by the bromide ions and the highest thermal stability. The turnover number was up to 47.6 DMC mol·(Cumol)^-1 with selectivity of 92.8% under conditions of 120 ℃, ratio of partial pressure of CO to O₂ of 19:1 (below the explosion limit of CO) and catalyst concentration of 0.011 mol·L^-1. Furthermore, a plausible reaction mechanism was suggested on the basis of the experimental data.

关键词: Dimethyl carbonate, Cu(phen)Br₂, Methanol, Oxidative carbonylation

Zhiping Du, Lihua Xiong, Zhikun Lin, Xuli Li, Yigang Ding, Yuanxin Wu. Oxidative Carbonylation of Methanol to Dimethyl Carbonate Over Cu(Ⅱ)-1, 10-Phenanthroline Bromide Complexes[J]. , 2014, 22(10): 1117-1121.

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