Chinese Journal of Catalysis ›› 2018, Vol. 39 ›› Issue (6): 1129-1137.DOI: 10.1016/S1872-2067(18)63069-4

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One-step aldol condensation reaction of dimethoxymethane and methyl acetate over supported Cs/ZSM-35 zeolite catalysts

Zhanling Maa,b,c, Xiangang Mab, Hongchao Liub, Wenliang Zhub, Xinwen Guoa, ZhongminLiub   

  1. a State Key Laboratory of Fine Chemicals, PSU-DUT Joint Center for Energy Research, School of Chemical Engineering, Dalian University of Technology, Dalian 116024, Liaoning, China;
    b National Engineering Laboratory for Methanol to Olefins, Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Dalian 116023, Liaoning, China;
    c University of Chinese Academy of Sciences, Beijing 100049, China
  • Received:2018-02-26 Revised:2018-04-02 Online:2018-06-18 Published:2018-05-16
  • Contact: 10.1016/S1872-2067(18)63069-4

Abstract:

This study was performed for the development of a green and promising approach for the synthesis of methyl acrylate and acrylic acid by a one-step aldol condensation reaction of dimethoxymethane and methyl acetate over cesium oxide-supported on ZSM-35 zeolite catalysts; the effect of base sites as well as acid sites on the aldol condensation reaction was studied in detail. It was found that base sites were harmful for aldol condensation due to their failure in catalyzing the decomposition of dimethoxymethane precursor into formaldehyde, whereas the acid site was indispensable for the reaction to proceed. This reaction cannot take place without an acid site. Although acid sites in H-form of the zeolite (HZSM-35) are indispensable for the aldol condensation reaction, not all of them tend to favor this reaction. A strong acid catalyzes methanol-to-olefin-like reactions resulting in hydrocarbon byproducts, which are finally transferred to hard coke. Medium strong acids and weak acids are great candidates for the target aldol condensation reaction with high activity and selectivity. A γ-Al2O3 sample with abundant weak-strength Lewis acid sites, together with a few medium-strong-strength acid sites, performs well with a high activity and considerable stability during the synthesis of methyl acrylate and acrylic acid.

Key words: Aldol condensation, Dimethoxymethane, Methyl acetate, Zeolite, Acidity