超声辅助SiO_2-Al_2O_3催化合成乙酰水杨酸工艺研究

Synthesis of Acetyl salicylic acid Catalyzed by SiO_2- Al_2O_3 under Ultrasound Irradiation

以水杨酸和乙酸酐为原料,环己烷为溶剂,SiO_2-Al_2O_3为催化剂合成乙酰水杨酸.最佳实验条件为:水杨酸与乙酸酐摩尔比为1∶3.5,SiO_2-Al_2O_3用量为水杨酸摩尔分数的8.4%,反应时间20 min,反应温度75℃,溶剂用量为水杨酸摩尔分数的14.9%,超声功率为90 W,乙酰水杨酸收率可达93.9%.催化剂重复使用5次后仍有较高催化活性.该法较传统方法催化效果更好,无腐酸排放,不腐蚀设备,后处理工艺简单,催化剂重复利用率高、易再生,是一种绿色高效合成乙酰水杨酸的方法 .

Using salicylic acid and acetic anhydride as raw materials, cyclohexane as solvent, SiO_2- Al_2O_3 as a catalyst for synthesis of Acetyl salicylic acid. The best conditions： salicylic acid and acetic anhydride molar ratio of 1 ∶3. 5,The catalyst dosage of SiO_2- Al_2O_3 was best for salicylic acid mole fraction of 8. 4%,20 min reaction time,reaction temperature 75 ℃,Dosage of solvent for salicylic acid mole fraction of 14. 9%,ultrasonic power is 90 W. Under these conditions,the yield of acetyl salicylic acid was 93. 9%. Catalyst can be reused five times and it still has high catalytic activity. This method is more efficient than traditional methods,which has no humic acid emissions,equipment corrosion.The post- treatment process is simple and the catalyst recycling rate is high. It is regenerated easily and an green and efficient way of synthesis of acetyl salicylic acid.