Mg-Al水滑石的制备及其对Aldol缩合反应的研究

摘要

采用共沉淀法制备了Mg-Al摩尔比为2:1及3:1的Mg-Al水滑石,通过FT-IR、XRD、TG-DTA对合成的水滑石进行了表征,并以其为催化剂前驱体经高温焙烧后得到MgO-Al2O3复合氧化物(LDO).研究了该复合氧化物(LDO)在环戊酮和正戊醛Aldol缩合反应中的催化性能.结果表明:Mg-Al摩尔比为3:1的水滑石在焙烧温度为500℃,酮醛摩尔比为3:1,催化剂用量为反应物总量的8%,于回流下(约122℃)反应4 h,生成的2-亚戊基环戊酮占生成物百分比为85.2%,正戊醛转化率为99.0%,催化活性高于MgO和Al2O3.%Mg-A1 hydrotalcite with Mg-AI molar ratios of 2:1 and 3: 1 was prepared by low saturated coprecipitation, the products were characterized by FT-IR, XRD, TG-DTA. MgO-AI2 O3 LDO was obtained from the calcination of the hydrotalcite precursor. And aldol condensation of cyclopentanone and valeraldehyde was studied by the catalyst of LDO. The optimal conditions are as follows: Mg-Al molar ratio 3: 1, calcination temperature 500 ℃, ketone/aldehyde molar ratio 3: 1, the amount of catalyst 8％ of the total reactant, under the reflux( about 122 ℃ ) for 4 hours. And the percentage of 2-pentyledene cyclopentanone in the total products is 85.2％, conversion of valeraldehyde is 99.0％, the catalytic activity is higher than MgO and Al203.