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首页> 外文期刊>Catalysis science & technology >Preparation of KF-La2O2CO3 solid base catalysts and their excellent catalytic activities for transesterification of tributyrin with methanol
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Preparation of KF-La2O2CO3 solid base catalysts and their excellent catalytic activities for transesterification of tributyrin with methanol

机译：KF-LA2O2CO3固体碱催化剂的制备及其出色的催化活性，用于甲醇的甲醇乳酸纤维酯化

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摘要

A series of 25% KF-La2O2CO3 catalysts (25-KF-LOC-x, x = 673, 723 and 773) were prepared at different calcination temperatures, which were tested as basic catalysts for the transesterification of tributyrin with methanol to produce methyl butyrate and characterized by means of XRD, SEM, CO2-TPD, FTIR, XPS and XRF. It was found that the calcination temperature greatly influences the catalytic activity, and its order is 25-KF-LOC-673 < 25-KF-LOC-723 < 25-KF-LOC-773. Especially, the 25-KF-LOC-773 catalyst exhibits a very high activity, and the conversion of tributyrin is nearly 100%, the yield of methyl butyrate reaches 94% at 308 K. The activation energy of the 25-KF-LOC-773 catalyst is as low as 55.03 kJ mol~(-1). The excellent catalytic activity of the 25-KF-LOC-773 catalyst can be attributed to the largest amount of surface hydroxyl among these 25-KF-LOC-x catalysts. The results indicate that the Bronsted base is the main active site at low reaction temperature. The recycling use and stability have been investigated over the 25-KF-LOC-773 catalyst. The results indicate that the 25-KF-LOC-773 catalyst has a high stability after being stored for 90 days. The deactivation of the used 25-KF-LOC-773 catalyst at 308 K is due to the loss of hydroxyl on the surface. However, the conversion of tributyrin can reach 91%, and the yield of methyl butyrate also can achieve 64% when the transesterification reaction is performed at 338 K over the second used 25-KF-LOC-773 catalyst, it indicates that the second used 25-KF-LOC-773 catalyst still possesses good catalytic activity at the higher reaction temperature due to the unchanged strong Lewis basic sites provided with surface oxygen anions.
机译：在不同的钙化温度下制备了一系列25％KF-LA2O2CO3催化剂（25 kf-loc-x，x = 673、723和773）并通过XRD，SEM，CO2-TPD，FTIR，XPS和XRF的平均值进行表征。发现钙化温度极大地影响了催化活性，其顺序为25 kf-loc-673 <25-kf-loc-723 <25-kf-loc-773。尤其是，25 kF-LOC-773催化剂的活性很高，而支流蛋白的转化率接近100％，在308 K时的甲基甲酯产量达到94％。 773催化剂低至55.03 kJ mol〜（-1）。 25-KF-LOC-773催化剂的优异催化活性可归因于这些25 kF-LOC-X催化剂中表面羟基的最大含量。结果表明，在低反应温度下，布朗斯特基碱是主要的活性位点。在25 kF-LOC-773催化剂中已经研究了回收利用和稳定性。结果表明，在储存90天后，25 kF-LOC-773催化剂具有很高的稳定性。在308 K时使用的25 kF-LOC-773催化剂的停用是由于表面上羟基的损失。然而，在第二次使用的25 kf-loc-773催化剂上，在338 K进行酯交换反应时，甲基丁酸甲酯的转化率可以达到91％，甲基丁酸甲酯的产率也可以达到64％。 25 kF-LOC-773催化剂在较高的反应温度下仍然具有良好的催化活性，这是由于未改变的强刘易斯基本位点带有表面氧阴离子。

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