无模板剂介孔锆基固体碱的制备及其催化合成甘油碳酸酯性能

Preparation of Mesoporous Zr-Based Solid Bases Without Templates for the Synthesis of Glycerol Carbonate

在无模板剂作用下,借助共沉淀法成功制备了3种不同组成的锆基固体碱催化剂(MO-ZrO2,M为Ca、Mg或La)。X射线衍射(XRD)和N 2吸附-脱附测试表明这些催化材料具有规整介孔结构。在催化剂制备过程中,所引入的金属氧化物进入了t-ZrO2四方相晶格,形成了固溶体结构。详细考察了所制备催化剂催化甘油和碳酸二甲酯(DMC)合成甘油碳酸酯(GC)的性能。在所制备的4种催化剂中,MgO-ZrO2具有最佳催化性能。在反应温度为120℃、反应时间为3 h、MgO-ZrO2用量为总反应物的5%(质量分数)的最佳条件下,GC收率可达到88.2%。结合CO2程序升温脱附(CO2-TPD)表征结果,阐明了催化剂反应性能和表面碱性之间的关系。重复性实验结果显示,所制备的MgO-ZrO2样品具有较高的催化稳定性,是一种理想的合成GC的多相催化剂。

Three kinds of Zr-based solid bases(MO-ZrO2,M=Ca,Mg or La)were successfully prepared via co-precipitation method without templates.As shown by the X-ray diffraction(XRD)and N2 adsorption-desorption characterization,they all have ordered mesoporous structures.Moreover,all the guest metal oxides are incorporated into the tetragonal lattice of t-ZrO2,resulting in the formation of solid solution.Then,their catalytic performances towards the synthesis of glycerol carbonate(GC)from glycerol and dimethyl carbonate(DMC)were investigated in detail.Among them,MgO-ZrO2 exhibites the best catalytic performance and the GC yield reaches 88.2%under the optimal reaction conditions(reaction temperature 120℃;reaction time 3 h;catalysts amount 5%(mass fraction)).Combined with the result of CO2-TPD,the relationship between the reactivity and the basic property for these samples were clarified.Furthermore,the reusability test information demonstrated that the prepared MgO-ZrO2 possesses relatively high catalytic stability,indicating that it is the heterogeneous catalyst for the GC production.