【摘要】 通过硝酸镧水溶液与锌铝氧化物的离子交换,制备了一系列镧改性锌铝氧化物。XRF分析表明镧离子主要与锌铝氧化物中锌离子交换,形成镧改性的金属氧化物,XRD分析表明镧的引入降低了锌铝氧化物中氧化锌的结晶度,锌2p轨道结合能的下降进一步证明Zn-O-La键的形成。以甘油与尿素合成环状碳酸甘油酯的反应为模型,评价了所得样品的催化性能,考察了镧的含量、催化剂的用量及反应条件对催化反应的影响。在145℃、5 kPa反应条件下,甘油质量1%的La0.66/Zn65.43Al33.91催化甘油和尿素(摩尔比1∶1)反应3 h后,甘油的转化率为88.4%,环状碳酸甘油酯选择性为96.5%。更多还原

【Abstract】 A series of lanthanum-modified zinc aluminum oxides were prepared by ion-exchange of zinc aluminum oxides with lanthanum ions in an aqueous solution of lanthanum nitrate. XRF analysis showed that lanthanum ions mainly exchanged with zinc ions to form lanthanum modified metal oxide. Based on the XRD analysis, the introduction of lanthanum reduced the crystallinity of zinc oxide in zinc aluminum oxide. The decrease of zinc 2 p orbital binding energy further confirmed the formation of Zn-O-La bond. The catalytic performance was evaluated with the reaction of glycerol with urea to synthesize cyclic glycerol carbonate as the model. The effects of lanthanum content, catalyst usage and reaction condition on the catalytic reaction ere also studied. Under the promotion by 1%(based on glycerol) La0.66/Zn65.43 Al33.91 at 145 ℃ and 5 kPa, the reaction of glycerol and urea was run at molar ratio of 1∶1 for 3 h to give glycerol carbonate with the conversion of glycerol and the selectivity of cyclic glycerol carbonate being 89.9% and 96.5%, respectively.更多还原