SiO_2负载磷钨酸(盐)催化剂对乙酰乙酸乙酯与乙二醇缩合反应的催化性能  

Catalytic Performance of Phosphotungstic Acid(Salt) Supported on SiO_2 for Acetalization of Ethyl Acetoacetate with Glycol

作　　者：张富民[1] 袁超树[1] 王军[1] 

机构地区：[1]南京工业大学化学化工学院,江苏南京210009

出　　处：《石油化工》2005年第12期1172-1176,共5页Petrochemical Technology

基　　金：国家自然科学基金项目(20306011;20476046);教育部高校博士点基金项目(20040291002);教育部留学归国人员基金资助项目

摘　　要：用浸渍法制备了一系列S iO2负载的磷钨酸(PW12)及其铯盐(Cs2.5H0.5PW12)和钾盐(K2.5H0.5PW12)催化剂,考察了这些催化剂对乙酰乙酸乙酯与乙二醇缩合制苹果酯反应的催化性能,并以X射线衍射、N2吸附-脱附和Hamm ett指示剂等方法表征了催化剂的物化性能。用水处理实验考察了催化剂的稳定性,溶脱到水中的杂多化合物浓度用紫外可见分光光度法测试。实验结果表明,在合成苹果酯的反应中,随磷钨酸(盐)负载量的增加,催化剂的活性有不同程度的增加,在负载量(质量分数)达到30%时,催化活性已基本不变,PW12/S iO2,Cs2.5H0.5PW12/S iO2,K2.5H0.5PW12/S iO2催化剂上,乙酰乙酸乙酯的转化率分别为69.8%,68.6%,68.4%,产物选择性为97%。催化剂的稳定性实验结果表明,催化剂失活与活性组分的流失有关,催化剂的稳定性顺序为:30%Cs2.5H0.5PW12/S iO2≈30%K2.5H0.5PW12/S iO2 30%PW12/S iO2。12 -phosphotungstic acid（ PW12 ） and/or its Cs salt and K salt supported on SiO2 were prepared by impregnation at ambient temperature. Their catalytic performances in synthesis of fructone by acetalization of ethyl acetoacetate with glycol were invetigated. Their properties were characterized by means of X - ray diffraction（XRD）, N2 adsorption and Hammett indicator. The catalyst stability was evaluated by treatment with water, during which concentration of leached heterpoly compound was measured by ultraviolet - visual spectrophotometer. The catalyst activity rose with increase of PW12 （ Cs - or K - salt） loading, and conversion of ethyl acetoacetate became steady when loading was more than 30%. For PW12/SiO2, Cs2.5 H0.5PW12/SiO2 and K2.5H0.5PW12/SiO2 catalysts, selectivity of fructone was 97%, and conversions of ethyl acetoacetate was 69.8%, 68.6% and 68.4%, respectively. The treatment of catalysts with water showed that deactivation of catalyst related correspondingly with the amount of leached active heteropoly species, and stabilities of three catalysts were in the order of 30% Cs2.5H0. 5PW12/SiO2 ≈30% K2.5 H0. 5 PW12/SiO2〉〉30% PW12/SiO2.

关 键 词：磷钨酸 磷钨酸盐 二氧化硅 催化剂 缩合 乙酰乙酸乙酯 乙二醇 苹果酯 

分 类 号：TQ426.91[化学工程]