Influence of dehydrating agents on the oxidative carbonylation of methanol for dimethyl carbonate synthesis over a Cu/Y-zeolite catalyst

doi:10.1016/j.cjche.2018.02.018

Abstract

Abstract: The influence of the dehydration by metal oxides on the synthesis of dimethyl carbonate (DMC) via oxidative carbonylation of methanol was studied. A Cu/Y-zeolite catalyst was prepared by the ion exchange method from CuCl₂·2H₂O and the commercial NH₄-form of the Y type zeolite. The catalyst was characterized by X-ray fluorescence (XRF), N2 adsorption (BET method), X-ray diffraction (XRD), and temperature-programmed desorption of ammonia (NH₃-TPD) to evaluate its Cu and Cl content, surface area, structure, and acidity. Reaction tests were carried out using an autoclave (batch reactor) for 18 h at 403 K and 5.5 MPa (2CH₃OH + 1/2O₂ + CO ? (CH₃O)₂CO + H₂O). The influence of various dehydrating agents (ZnO, MgO, and CaO) was examined with the aim of increasing the methanol conversion (X_MeOH, MeOH conversion). The MeOH conversion increased upon addition of metal oxides in the order CaO >> MgO > ZnO, with the DMC selectivity (S_DMC) following the order MgO > CaO > ZnO. The catalysts and dehydrating agents were characterized before and after the oxidative carbonylation of methanol by thermogravimetric and differential thermogravimetric (TG/DTG), and XRD to confirm that the dehydration reaction occurred via the metal oxide (MO + H₂O → M(OH)₂). The MeOH conversion increased from 8.7% to 14.6% and DMC selectivity increased from 39.0% to 53.1%, when using the dehydrating agent CaO.

Key words: Carbon monoxide, Zeolite, Catalyst, Dimethyl carbonate, Oxidative carbonylation, Dehydrating agent

摘要： The influence of the dehydration by metal oxides on the synthesis of dimethyl carbonate (DMC) via oxidative carbonylation of methanol was studied. A Cu/Y-zeolite catalyst was prepared by the ion exchange method from CuCl₂·2H₂O and the commercial NH₄-form of the Y type zeolite. The catalyst was characterized by X-ray fluorescence (XRF), N2 adsorption (BET method), X-ray diffraction (XRD), and temperature-programmed desorption of ammonia (NH₃-TPD) to evaluate its Cu and Cl content, surface area, structure, and acidity. Reaction tests were carried out using an autoclave (batch reactor) for 18 h at 403 K and 5.5 MPa (2CH₃OH + 1/2O₂ + CO ? (CH₃O)₂CO + H₂O). The influence of various dehydrating agents (ZnO, MgO, and CaO) was examined with the aim of increasing the methanol conversion (X_MeOH, MeOH conversion). The MeOH conversion increased upon addition of metal oxides in the order CaO >> MgO > ZnO, with the DMC selectivity (S_DMC) following the order MgO > CaO > ZnO. The catalysts and dehydrating agents were characterized before and after the oxidative carbonylation of methanol by thermogravimetric and differential thermogravimetric (TG/DTG), and XRD to confirm that the dehydration reaction occurred via the metal oxide (MO + H₂O → M(OH)₂). The MeOH conversion increased from 8.7% to 14.6% and DMC selectivity increased from 39.0% to 53.1%, when using the dehydrating agent CaO.

关键词: Carbon monoxide, Zeolite, Catalyst, Dimethyl carbonate, Oxidative carbonylation, Dehydrating agent

Dong-Ho Lee, Jiin You, Je-Min Woo, Jung Yoon Seo, Young Cheol Park, Jong-Seop Lee, Hyunuk Kim, Jong-Ho Moon, Seung Bin Park. Influence of dehydrating agents on the oxidative carbonylation of methanol for dimethyl carbonate synthesis over a Cu/Y-zeolite catalyst[J]. Chin.J.Chem.Eng., 2018, 26(5): 1059-1063.

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