基于咔唑的碳基固体酸催化剂制备及催化合成柠檬酸三丁酯

Preparation of carbon-based solid acid catalyst based on carbazole and its application in synthesis of tributyl citrate

以对苯二甲醛与咔唑共聚形成的微孔有机骨架为前驱体,经高温水热碳化、氯磺酸磺化制备一种碳基固体酸催化剂。通过FT-IR、SEM等表征手段证明合成的催化剂为形貌规整、高酸密度、良好稳定性的球形。以该催化剂催化柠檬酸与正丁醇酯化合成环保增塑剂柠檬酸三丁酯作为探针反应,最适宜的反应条件为:酸醇摩尔比为1∶4、反应温度为145℃、催化剂用量为3 g/(mol酸),此时,柠檬酸转化率高达99. 57%,产物纯度为99. 30%。该催化剂具有较好的重复利用性,循环使用5次后柠檬酸的转化率仍可达到92. 60%。

A carbon-based solid acid catalyst is prepared via hydrothermal at high temperature and chlorosulfonic acid sulfonation with a new microporous organic framework copolymerized between terephthalaldehyde and carbazole.Through characterization by Fourier transform infrared(FT-IR),scanning electron microscopy(SEM)and other methods,the catalyst is verified to be a spherical catalyst with a regular morphology,high acid density and good stability.The esterification of citric acid with n-butanol over this catalyst is used as a probe reaction to synthesize environmentalfriendly plasticizer tributyl citrate.The optimum conditions for the reaction are as follow:the molar ratio of citric acid and butanol is 1∶4 and the adding mass of the catalyst is 3 g per mol citric acid and the esterification reaction temperature is controlled at 145℃.Under these conditions,the conversion rate of citric acid reaches 99.57%and the product purity reaches 99.30%.The catalyst shows an excellent reusability,the conversion rate of citric acid can still reach 92.60%after the catalyst has been reused for five cycles.