Fe-Ce/SiO2固体碱催化剂用于制备碳酸二甲酯

Fe-Ce/SiO2 solid base catalyst for preparing dimethyl carbonate

采用化学还原法制备亚价负载铁催化剂,通过空气氧化为Fe3+碱性活性中心。考察了该催化剂在碳酸丙烯酯与甲醇酯交换制备碳酸二甲酯反应中的活性和选择性。采用N2吸附-脱附、TEM、XRD、XPS和CO2-TPD等对所制备的催化剂进行了表征。结果表明:催化剂的表面结构与碱性是影响其活性的重要因素。相对于Fe或Ce单金属催化剂,Fe-Ce/SiO2催化剂的碱量大幅度提升,且Fe与Ce通过相互作用形成了稳定的非晶态结构。在醇酯比为15∶1、反应温度为140℃、催化剂用量为反应物总质量的0.5%、Ce/Fe原子比为2∶1的反应条件下,碳酸丙烯酯转化率为88%,碳酸二甲酯的选择性为92%。催化剂在循环使用10次之后,其活性保持不变。

A tetravalent supported iron catalyst is prepared by chemical reduction and oxidized to a Fe3+basic active center by air.The activity and selectivity of the catalyst in the transesterification of propylene carbonate with methanol to prepare dimethyl carbonate were evaluated.The prepared catalysts were characterized by N2 adsorption-desorption,TEM,XRD,XPS and CO2-TPD.Compared with Fe or Ce single metal catalyst,the basic amount of Fe-Ce/SiO2 catalyst is greatly improved,and the interaction between Fe and Ce formed a stable amorphous structure.Propylene carbonate conversion of 88%and dimethyl ester selectivity of 92%were reached under the reaction conditions of alcohol ester molar ratio of 15∶1,reaction temperature of 140℃,catalyst dosage of 0.5%of the total mass of the reactants,and Ce/Fe atomic ratio of 2∶1.The activity of the catalyst remained unchanged after 10 cycles of use.