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采用超声波浸渍法制备了活性炭负载12-磷钨酸催化剂,并通过红外光谱、X-射线衍射、N2吸附-脱附和SEM等方法对其进行表征。以柠檬酸三丁酯的合成为探针反应,评价该催化剂的活性。结果表明,磷钨酸负载到活性炭后保持了原有的Keggin结构;在磷钨酸负载量为25%、催化剂占酸醇总质量的7 wt%、n(柠檬酸)∶n(正丁醇)=1∶4、回流时间为4 h的条件下,酯化率可达97.6%。催化剂重复使用5次,仍具有较高的活性。
Activated carbon supported 12-phosphotungstic acid catalyst was prepared by ultrasonic impregnation and characterized by IR, X-ray diffraction, N2 adsorption-desorption and SEM. The synthesis of tributyl citrate was used as a probe reaction to evaluate the activity of the catalyst. The results showed that the original Keggin structure was retained after the phosphotungstic acid was loaded on the activated carbon. When the loading of phosphotungstic acid was 25%, the catalyst accounted for 7 wt% of the total mass of the alcoholic acid, n (citric acid): n ) = 1: 4, the reflux time of 4 h under the conditions, the esterification rate of up to 97.6%. Reuse of catalyst 5 times, still has high activity.