负载杂多酸（盐）的表征及其在苹果酯合成反应中的催化性能

用浸渍法制备了一系列负载型磷钨酸及其铯盐催化剂，载体包括超稳Y沸石（USY）、脱铝超稳Y沸石（DUSY）、SiO₂和SBA-15，测定了催化剂的比表面积和酸强度，并在乙酰乙酸乙酯与乙二醇液相缩合制取苹果酯反应中考察了催化剂的性能.结果表明，这些负载型杂多化合物催化剂都表现出较高的催化活性.然而，催化剂在水中的溶脱性能实验表明，负载型磷钨酸催化剂存在严重的活性组分流失现象，不能重复使用，而DUSY负载的磷钨酸铯盐催化剂不仅表现出较高的催化活性，而且显示出较好的重复使用性能.在优化的反应条件下30% (质量分数) Cs_2.5H_0.5PW/DUSY催化剂上乙酰乙酸乙酯的转化率可达98.7%，苹果酯的选择性大于97%.

Characterization of supported heteropoly acid (salt) and its catalytic behavior in synthesis of fructone

A series of 12-phosphotungstic acid(PW)and its cesium salt catalysts immobilized on various supports such as ultra-stable Y zeolite (USY), dealuminated USY (DUSY), SiO_2 and SBA-15 were prepared. Their specific surface area and acid strength were measured, and their catalytic performance was evaluated in the synthesis of fructone by acetalization of ethyl acetoacetate with ethylene glycol. The high catalytic activity was found over the prepared supported heteropoly compound catalysts in this reaction. However, for the supported PW catalysts, a severe leaching of heteropoly anions into water was observed, leading to their poor reusability. By contrast, the Cs salt of PW catalyst supported on DUSY exhibited very high catalytic activity with high water tolerance and reusability. The conversion of ethyl acetoacetate of 98.7% with the selectivity of fructone above 97% could be obtained over 30%Cs_ 2.5H_ 0.5PW/DUSY under the optimal reaction conditions.