Mg/Al复合氧化物催化丙酮和碳酸二甲酯合成乙酰乙酸甲酯

摘要

利用先共沉淀后水热处理的方法制备出水滑石前体,将其焙烧后,得到具有不同Mg/Al摩尔比的复合氧化物,并借助电感耦合等离子原子发射光谱、XRD、CO2-TPD和氮气吸脱附等手段对其进行表征。结果表明,Mg/Al摩尔比对催化剂的结构和碱性质有较大的影响,并且在催化丙酮和碳酸二甲酯合成乙酰乙酸甲酯的反应中,其比单纯的氧化镁和氧化铝表现出了更高的催化活性。进一步的研究表明,在该反应中是复合氧化物的中强碱性位起催化活性的作用,当Mg/Al摩尔比为2时,催化剂具有最高的活性。此外,重复性实验表明,这些催化剂具有较好的稳定性和重复使用性。%A series of Mg/Al mixed oxides with different Mg/Al mole ratios were prepared by calcining hydrotalcite obtained via the co-precipitation method followed hydrothermal treatment.The samples were characterized by using ICP,XRD,CO2-TPD and N2adsorption/desorption techniques.The results showed that the structure and basicity of samples were affected by Mg/Al mole ratio.Besides,these Mg/Al mixed oxides were effective catalysts for the synthesis of methyl acetoacetate from acetone and dimethyl carbonate.More importantly,they all presented much higher catalytic ability than the pure MgO or Al2O3.At the same time,the catalytic performance of mixed oxides was correlated with their moderate basicity,and the catalyst exhibited the highest catalytic ability when the initial Mg/Al mole ratio was 2.Furthermore,reusability test indicated that these Mg/Al mixed oxides presented good stability and reusability.