MgO-SBA-15 Supported Pd-Pb Catalysts for Oxidative Esterification of Methacrolein with Methanol to Methyl Methacrylate

doi:10.1016/j.cjche.2014.08.002

Abstract

Abstract: Novel MgO-SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein (MAL) with methanol to methyl methacrylate (MMA). The MgO-SBA-15 supports were synthesized with different magnesia loadings fromdifferentmagnesiumprecursors and hydrochloric acidmolar concentrations. The MgO-SBA-15 supports and Pd-Pb/MgO-SBA-15 catalysts were characterized by several analysismethods. The results revealed that the addition ofMgO improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd₃Pb particles onmagnesia-modified Pd-Pb/MgO-SBA-15 catalystswas smaller than that on the pure silica-based Pd-Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd-Pb/MgO-SBA-15 catalysts had higher activity than pure silica-based Pd-Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd-Pb/SBA-15 catalysts and Pd-Pb/MgO-SBA-15 catalystswas due to the discrepant structural properties and surface alkalinity provided by MgO, which led to the different Pd₃Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.

Key words: Methacrolein, Methyl methacrylate, Oxidative esterification, Pd-Pb bimetal, SBA-15

摘要： Novel MgO-SBA-15 supported catalysts were prepared for oxidative esterification of methacrolein (MAL) with methanol to methyl methacrylate (MMA). The MgO-SBA-15 supports were synthesized with different magnesia loadings fromdifferentmagnesiumprecursors and hydrochloric acidmolar concentrations. The MgO-SBA-15 supports and Pd-Pb/MgO-SBA-15 catalysts were characterized by several analysismethods. The results revealed that the addition ofMgO improved the ordered structure of SBA-15 supports and provided surface alkalinity of SBA-15 supports. The average size of the Pd₃Pb particles onmagnesia-modified Pd-Pb/MgO-SBA-15 catalystswas smaller than that on the pure silica-based Pd-Pb/SBA-15 catalysts. The experiments on catalyst performance showed that the magnesia-modified Pd-Pb/MgO-SBA-15 catalysts had higher activity than pure silica-based Pd-Pb/SBA-15 catalysts, showing the strong dependence of catalytic activity on the average size of active particles. The difference of activity between Pd-Pb/SBA-15 catalysts and Pd-Pb/MgO-SBA-15 catalystswas due to the discrepant structural properties and surface alkalinity provided by MgO, which led to the different Pd₃Pb particle sizes and then resulted in the different number of active sites. Besides magnesia loadings, other factors, such as hydrochloric acid molar concentration and magnesium precursors, had considerable influences on the catalytic activity.

关键词: Methacrolein, Methyl methacrylate, Oxidative esterification, Pd-Pb bimetal, SBA-15

Li Jiang, Yanyan Diao, Junxing Han, Ruiyi Yan, Xiangping Zhang, Suojiang Zhang. MgO-SBA-15 Supported Pd-Pb Catalysts for Oxidative Esterification of Methacrolein with Methanol to Methyl Methacrylate[J]. , 2014, 22(10): 1098-1104.

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