酸改性HZSM–5分子筛催化合成柠檬酸正丁酯

Catalyzed Synthesis of Tri-n–butyl Citrate by Acid Modified HZSM–5

研究了酸改性HZSM–5分子筛(硅铝比25)合成绿色增塑剂柠檬酸正丁酯的最佳工艺条件。通过在不同酸改性浓度、改性时间、反应温度、反应时间、催化剂用量、酸醇物质的量之比等实验条件下,研究酸改性HZSM–5改性分子筛对绿色增塑剂产率的影响,并在最适宜条件下研究了柠檬酸正丁酯的最佳产率,同时,进行了酸改性HZSM–5分子筛的回收实验,测定多次回收分子筛对柠檬酸酯产率影响的变化规律。结果表明,酸改性HZSM–5分子筛催化合成柠檬酸正丁酯的最佳工艺条件为:改性酸浓度为5mol/L,改性时间为10h,催化剂用量为柠檬酸用量的4%,柠檬酸与正丁醇的物质的量之比为1∶6,反应温度为130℃,反应时间为3h,最佳酯化产率可达95.90%。酸改性HZSM-5分子筛至少可回收循环使用2次。

The optimum technological conditions for synthesis of green plasticizer tri-n-butyl citrate by acid modified HZSM–5(Si/Al ratio 25)were studied.The synthesis effect of plasticizer production rate were researched under the different condition of acid modified concentration,modification time,reaction temperature,reaction time,catalyst dosage,molar ratio of acid to alcohol.Under optimum condition,the best production rate of tri-n-butyl acetate and the change law of the citric acid ester yield using recycled molecular sieve were determined at the same time.The experimental results show that the optimum technological conditions of acid modified HZSM–5 molecular sieve catalytic synthesis tri-n-butyl acetate are modified acid concentration is 5 mol/L,modification time is 10 h,dosage of catalyst is 4%,citric acid and n-butyl alcohol of the amount of substance ratio is 1∶6,reaction temperature is 130℃,reaction time is 3 h,and best productive rate is 95.90%.Modified HZSM–5 molecular sieve can be recycled at least twice.