Abstract:

Cu-doped Mg-Al layered double oxides were obtained through calcination at 400 ℃ from the corresponding Cu-doped Mg-Al hydrotalcite，which was prepared by wetness impregnation. The structural information of Cu/LDO catalysts was characterized by XRD，SEM，TG and nitrogen-adsorption/desorption techniques. Their catalytic activities were studied in the synthesis of propylene carbonate from urea and 1,2-propylene glycol. The influences of Cu doping amount，mole ratio of Mg-Al and different supports were investigated. The regeneration performance of catalysts was also studied. The results indicate that the combination of 1% Cu loading，3∶1 Mg∶Al mole ratio，Cu/Mg-Al LDO（3）gives much higher activity in propylene carbonate synthesis. Under the reaction condition of 1% Cu/ Mg-Al LDO（3），n(1,2-propylene glycol)∶n(urea)= 4∶1，reaction temperature of 170 ℃ and reaction time of 3 h，the yield of propylene carbonate reaches 96.1%. In a set of reuse experiments，there is almost no reduction on the catalytic activity.

摘要：

采用浸渍法制备了Cu掺杂的镁铝水滑石类化合物Cu/HT，经过400 ℃焙烧得到Cu掺杂的镁铝复合金属氧化物Cu/ Mg-Al LDO，利用X射线衍射（XRD）、扫描电镜（SEM）、热重分析（TG）、N₂吸附-脱附等技术对催化剂的结构进行了表征。研究了其对尿素与1,2-丙二醇合成碳酸丙烯酯的催化性能。考察了Cu掺杂量、镁铝比、不同催化剂载体等催化剂制备条件对催化剂活性的影响，同时考察了催化剂的再生性能。结果表明，当Cu掺杂量为1%、镁铝比摩尔为3∶1时的Cu/Mg-Al LDO（3）对尿素与1,2-丙二醇合成碳酸丙烯酯具有比较好的催化活性，在170 ℃、1,2-丙二醇与尿素的摩尔比为4∶1、催化剂用量为原料总质量的1%、反应3 h时，碳酸丙烯酯的收率达到96.1%，且催化剂经4次再生重复使用，催化活性稳定。