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以磁性复合微粒SiO_2/Fe_3O_4为载体,采用浸渍法制备了磁性氧化镁催化剂,并用IR和XRD对其进行表征,考察了催化剂对尿素与1,2-丙二醇合成碳酸丙烯酯反应的影响。以硝酸镁为前驱体,负载量(质量分数)为25%,在600℃下焙烧制得的催化剂催化活性最好。通过对实验结果进行分析,得到最优反应条件:催化剂质量分数(占反应物总质量)1.0%,n(PG)∶n(尿素)=2∶1,反应时间为3 h,反应温度为180℃。在此反应条件下,PC的最高收率达到89.49%。反应为多相催化体系,因催化剂有磁性,在磁场环境下可方便实现催化剂与产物的分离。
Magnetic magnesium oxide catalysts were prepared by impregnation method using magnetic composite particles SiO_2 / Fe_3O_4 as support. The catalysts were characterized by IR and XRD. The effects of catalysts on the reaction of propylene carbonate with 1,2-propanediol were investigated. Magnesium nitrate as a precursor, the loading (mass fraction) of 25%, calcined at 600 ℃ catalyst prepared the best catalytic activity. Through the analysis of the experimental results, the optimal reaction conditions were obtained: catalyst mass fraction (1.0% of the total reactants), n (PG): n (urea) = 2:1, reaction time 3 h, reaction temperature 180 ℃. Under the reaction conditions, the highest yield of PC reached 89.49%. The reaction is heterogeneous catalytic system, because the catalyst is magnetic, catalyst and product separation can be conveniently realized in a magnetic environment.