Dawson结构磷钨酸银催化绿色合成阿司匹林

Green Synthesis of Aspirin Catalyzed by Silver Salts of Tungstophosphoric with Dawson Structure

通过沉淀法制备出Dawson结构磷钨酸银(Ag3H3P2W18O62·n H2O),采用FT IR、EDX对其进行了表征,并将其用于催化乙酸酐和水杨酸合成阿司匹林。研究了催化剂用量、水杨酸和乙酸酐摩尔比、反应温度、反应时间等因素对反应的影响。结果表明,所制磷钨酸银在多次使用后仍保持Dawson结构不变。在优化条件下,即n(水杨酸)∶n(乙酸酐)=1∶1.75,反应温度为90℃,催化剂用量为3.2%(以反应物质量计),反应时间为20min,阿司匹林收率为90.1%。催化剂重复使用5次,阿司匹林收率仍可保持为82.4%。

Silver salts of tungstophosphoric with Dawson structure（ Ag3H3P2W18O62·n H2O） was prepared by precipitation method and characterized by FT IR and EDX. Then it was employed as the catalyst for the synthesis of aspirin from salicylic acid and acetic anhydride. The effects of catalyst dosage, ratio of reactants, reaction temperature and reaction time on the yield of aspirin were investigated. The results showed that as-prepared silver tungstophoric acid catalyst kept primary Dawson structure after reuse for several times. Under the optimum reaction conditions,i. e.,the molar ratio of salicylic acid to acetic anhydride was 1∶ 1. 75,the weight ratio of Ag3H3P2W18O62 to reactants was 3. 2%,the reaction temperature was 90℃ and the reaction time was 20 min,the yield of aspirin could reach 90. 1%. The catalyst can be reused for 5 times with yield of aspirin of 82. 4%.