气相催化丙酸与甲醛缩合反应制甲基丙烯酸

采用等体积浸渍法制备一系列Cs负载催化剂,采用XRD、ICP和物理吸附等对催化剂进行表征。在固定床反应器中进行气相催化丙酸与甲醛羟醛缩合反应制备甲基丙烯酸,以多聚甲醛解聚液为甲醛源头,考察载体种类、Cs负载量、铯源、反应温度及载气流速等对催化剂催化性能的影响。结果表明,较优的工艺条件为:反应温度340℃,活性组分Cs负载质量分数10%,丙酸与甲醛物质的量比1∶2,载气N2流速60 mL·min^(-1),此条件下,催化剂具有较好的催化活性,甲基丙烯酸收率为26%,甲基丙烯酸选择性为90.4%。

Catalytic gas-phase condensation of propionic acid with formaldehyde to methacrylic acid

A series of supported Cs catalysts were prepared by co-precipitation method, and characterized by XRD, ICP and physical adsorption.The catalyst was tested in gas-phase aldol condensation of propionic acid and formaldehyde to methacrylic acid in fixed-bed reactor with depolymerization solution of paraformaldehyde as formaldehyde source.Effects of carrier type,Cs loading,source of Cs,reaction temperature and carrier gas flow rate on catalytic performance were investigated.Results showed that the optimum conditions were that reaction temperature 340 ℃,10wt% Cs-loading,PA/HCHO=1∶2,carrier gas N₂=60 mL·min^-1. The catalyst exhibited good catalytic activity,and MAA yield and MAA selectivity reached 26% and 90.4%,respectively.