中文摘要：

以4A-分子筛为载体,Dawson结构磷钨酸钇（Y2P2W（18）O（62）·nH2O）为活性组分,采用浸渍法制备出负载型40%Y2P2W（18）O（62）·nH2O/4A-分子筛,并通过FT IR、EDS、SEM、NH3-TPD及N2吸附-脱附等方法对催化剂进行表征。将其用于催化水杨酸和乙酸酐反应制备乙酰水杨酸,考察了各因素对反应的影响。结果表明,负载前后磷钨酸钇均保持Dawson结构,Y2P2W（18）O（62）·nH2O和40%Y2P2W（18）O（62）·nH2O/4A-分子筛均呈球形,负载后催化剂的比表面积增大,酸强度和酸量均明显提高。在优化反应条件（水杨酸与乙酸酐摩尔比为1∶3,反应时间为30min,催化剂用量为反应物质量分数的2.3%）下,乙酰水杨酸收率为95.2%。催化剂重复使用6次,乙酰水杨酸收率仍保持为77.9%。

英文摘要：

The Dawson type yttriumphosphotungstates supported on 4A zeolite（Y2P2W（18）O（62）·nH2O/4A zeolite）with different loading level were prepared by immersion process and characterized by FT IR,SEM,EDS,NH3-TPD and N2adsorption-desorption. They were applied to the synthesis of acetylsalicylic acid. The influences of catalyst dosage,the mole ratio of reactants,reaction temperature,reaction time and reusability of catalyst on the synthesis were investigated. The results showed that as-prepared yttriumphosphotungstates kept Dawson structure before or after loading on 4A zeolite. BothY2P2W（18）O（62）·nH2Oand 40%Y2P2W（18）O（62）·nH2O/4A zeolite took the form of spheres.The specific surface area,acid strength and acid amount were enhanced by loadingY2P2W（18）O（62）·nH2Oon 4A zeolite.The optimal conditions of synthesis reaction were as follows： w（Y2P2W（18）O（62）·nH2O/4A zeolite） was 2. 3%,the molar ratio of salicylic acid to acetic anhydride was 1∶ 3,reaction temperature of 80℃,reaction time of 30 min. The yield of acetylsalicylic acid could reach 95. 2% under the optimum conditions and kept 77. 9% after the catalyst being used six times.