膨润土负载型固体酸的制备、表征及催化乙酰水杨酸合成反应

Solid Acid Catalyst Loaded on Bentonite and Its Catalysis of the Synthesis of Acetylsalicylate

用无水浸渍法制备了膨润土负载型固体酸催化剂,以乙酰水杨酸合成反应为探针考察了制备及反应条件对催化性能的影响,通过XRD、DTA及离子酸度等分析测试技术对催化剂进行表征分析。结果表明,当用体积分数10%HCl浸泡12 h以上,负载5.0 mmol/g ZnCl2或4.0 mmol/g CuCl2,550℃下焙烧活化3 h,制备固体酸及固体酸用量为水杨酸的5%,水杨酸和乙酸酐投料摩尔比为1∶2,反应温度为80～90℃,反应时间为1 h,产率可达96.6%。制备的固体酸催化剂可替代浓硫酸并能重复使用。

Solid acid catalysts loaded on bentonite were prepared through anhydrous impregnation, and acetylsalicylate synthesis was used as a probe to inspect the influence of the preparation conditions of the catalysts and reaction conditions of acetylsalicylate synthesis on the catalytic properties. The catalysts were characterized by XRD, DTA, and iconic acid test. The result showed that the solid acid catalysts had the best catalytic capability after soaked in 10% HCl for overnight, loaded with 5.0 mmol/g ZnCl2 and 4. 0 mmol/g CuCl2, and baked at a temperature of 550 ℃ for 3 h. And the preparation conditions of acetylsalicylate synthesis were as follows ： the optimum temperature was 80 - 90 ℃ ; the optimum time was 1 h ; the ratio of salicylic to acetic acid was 1：2, and the quantity of solid acid was 5% that of salicylic acid. Under these conditions, the yield of acetylsalicylate reached 96.6%, and the solid acid catalysts can replace sulfuric acid and can be reused.