稀土固体超强酸S2O82-/ZrO2-La2O3催化合成柠檬酸三丁酯

摘要

Tributyl citrate(TBC) was synthesized by reaction of citric acid with n-butanol using rare earth solid su⁃peracid S2O82-/ZrO2-La2O3 as the catalyst. Effects of La content on the catalyst structures were determined by using XRD and FT-IR. Effects of catalyst dosage, molar ratio of n-butanol to citric acid, reaction time on the esterifica⁃tion rates were explored by orthogonal experiment. Results show that the catalyst can present the best behavior un⁃der concentration of the La content of 0.07 mol·L-1. The optimum synthesis condition of TBC adds 4 times of n-bu⁃tanol to citric acid, under the condition of temperature 175℃for 180 min using 2.0 wt%catalyst, with the yield of ester reaching 98.27%. The catalyst can be reused for 5 times without significant decline in its behavior. The struc⁃ture of the product was qualitatively analyzed by refractive index, FT-IR, 1H-NMR, and 13C-NMR.%以柠檬酸和正丁醇为原料，在稀土超强酸S2O82-/ZrO2-La2O3的催化下合成柠檬酸三丁酯。通过XRD和红外光谱确定了稀土元素La的掺量对催化剂结构的影响，用正交优化实验优化了催化剂用量、酸醇摩尔比、反应时间等对酯化率的影响。实验结果表明：La掺量为0.07 mol·L-1所得催化剂性能最佳，柠檬酸三丁酯最优催化合成条件为反应温度175℃，醇酸摩尔比4.0∶1，催化剂用量为柠檬酸质量的2.0%，反应时间180 min，酯化率可达98.27%。催化剂可循环使用5次而不会明显降低活性。经折光率、红外光谱、核磁共振氢谱和碳谱测定，所合成产物为柠檬酸三丁酯。