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

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N2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。

Preparation of Mesoporous Zr-based Solid bases without Template for the Synthesis of Glycerol Carbonate

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 oft-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.