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出 处:《高校化学工程学报》2008年第1期128-133,共6页Journal of Chemical Engineering of Chinese Universities
摘 要:采用二步浸渍法制备硅胶负载磷钨酸铯(Cs2,H0.5PW12O40)催化剂催化合成药物中间体2-乙酰噻吩。运用IR和XR试D测技术进行了Cs2.5H0.5PW12O40/SiO2催化剂的表征,考察了Cs2.5H0.5PW12O40负载量、催化剂用量、物料配比、反应温度、反应时间等对2-乙酰噻吩合成收率和选择性的影响。实验结果表明,Cs2.5H0.5PW12O40和Cs2.5H0.5PW12O40/SiO2催化剂保持H3PW12O40的Keggin结构不变,且Cs2.5H0.5PW12O40/SiO2催化剂中Cs2.5H0.5PW12O40主要聚集在SiO2载体表面。优化合成2-乙酰噻吩的工艺条件为:30%Cs2.5H0.5PW12O4dSiO2催化剂用量为3%(以总物料量计);噻吩与乙酐的摩尔比为4:1;反应温度为75~80℃;反应时间为90min。在此所选择的条件下,2-乙酰噻吩的收率达946%-96.8%,选择性达998%-99.9%。Via two steps impregnating method, the SiO2-supported cesium-substituted dodecatungstophosphate (Cs2.5H0.5PW12O40) catalysts used for the synthesis of pharmaceutical intermediate 2-acetylthiophene were prepared. The experimental results show that in catalysts Cs2.5H0.5PW12O40 and Cs2.5H0.5PW12O40/SiO2, the primary Keggin structure of dodecatungstophosphate is preserved, and in the Cs2.5H0.5PW12O40/SiO2 catalysts, the dodecatungstophosphates mainly accumulate on the surface of the support SiO2. The optimum reaction conditions for 2-acetylthiophene synthesis were found as following: the amount of 30%Cs2.5H0.5PW12O40/SiO2 catalyst used is 3.9% (wt) of the total reaction mixture, molar ratio of thiophene to acetic anhydride is 4, reaction temperature is 75-80℃ and reaction time is 90 min. Under above selected conditions, the yield and selectivity of 2-acetylthiophene are 94.6%-96.8% and 99.8%-99.9%, respectively.
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