Solid acid catalysts (especially solid superacid catalysts) used in esterification have the advantages of good selectivity, fast reaction speed, high yield, easy separation, convenient operation, stable catalyst, reusable, no corrosion of equipment, no pollution, etc. , is a catalyst with good development prospects. Using citric acid and n-butanol as raw materials, TBC was synthesized under the catalysis of rare earth superacid. The experimental results show that the performance of the catalyst obtained with La content of 0.07mol/L is the best, and the optimal catalytic synthesis conditions of TBC are: reaction temperature 175°C, alkyd-acid molar ratio 4.0:1, catalyst dosage 2.0% of citric acid mass, reaction The time is 180 minutes, and the esterification rate can reach 98.27%. The catalyst can be recycled 5 times without significant loss of activity.
The esterification of citric acid and n-butanol to TBC was catalyzed by solid acid catalyst supported on activated carbon. The optimal reaction conditions are: catalyst dosage 5% (mole fraction), acid-alcohol molar ratio 4.5:1, reaction temperature 140°C, reaction time 3.0h, and the esterification rate can reach over 98%. The catalyst can still maintain a high catalytic activity after being used for 5 times, and the catalyst can be regenerated by adding NaH.sO by spraying. The supported MoO solid superacid catalyst was prepared by slurry impregnation method, and it was used to catalyze the synthesis of TBC from citric acid monohydrate and n-butanol. The results show that with MoO/activated carbon as the catalyst, the catalyst dosage is 8% (w/w), the molar ratio of acid to alcohol is 1:4, the reaction temperature is 140cC, and the reaction time is 3.0h, the esterification rate can reach more than 99%. In addition, the catalyst can be recycled more than 5 times, and the esterification rate remains at a high level.