硅藻土负载磷钨酸催化合成阿司匹林

Synthesis of Aspirin Catalyzed by Diatomite Supported Phosphotungstic Acid

本实验通过控制单因素变量探究磷钨杂多酸的浸渍时间、磷钨杂多酸浸渍浓度、原料比例、反应时间等因素对阿司匹林合成的影响。研究结果发现催化剂制备的较优条件是在25℃下用0.046 mol/L的磷钨杂多酸溶液浸渍硅藻土,浸渍时间6 h;最佳反应条件是温度为80℃,反应时间30 min,m_(水杨酸)∶m_(乙酸酐)=1∶2,此条件下阿司匹林的产率为0.5918。在最佳反应条件下对催化剂的重复使用效果进行了实验。实验结果表明,催化剂在重复试验6次之后,催化合成阿司匹林的产率仍在45%以上,说明催化剂的重复使用率高,不易失去活性。

In this study, the effects of immersion time, phosphotungstic acid concentration and raw material ratio on aspirin synthesis were investigated by single factor experiments. The results showed that the optimum preparation conditions were diatomite impregnated with 0.046 mol/L phosphotungstate heteropoly acid solution at 25 ℃ for 6 h. The yield of aspirin reached 59.18 % after 30 min reaction at 80 ℃, while the mass ratio of salicylic acid and acetic anhydride was 1∶2. The experiment was repeated under the optimum reaction conditions. After 6 times of repeated test, the yield of aspirin was still above 45 %, indicating that the catalyst could be reused maintaining relatively high activity.