负载型催化剂催化合成柠檬酸三丁酯和柠檬酸三辛酯若干问题的研究.pdf

摘 要本论文以柠檬酸和正丁醇合成柠檬酸三丁酯(TBC),考察了柠檬酸三丁酯的酯化合成体系,系统研究了坡缕石负载四种杂多酸催化剂在柠檬酸与正丁醇酯化反应中的催化性能,同时还研究了柠檬酸三辛酯、柠檬酸三异辛酯的合成。首先以乙酸正丁酯的合成为探针实验,研究了坡缕石负载硅钨酸和磷钨酸在酯化反应中的催化活性,采用正交试验法对催化剂的制备条件进行优化。实验结果表明,采用不同酸活化坡缕石负载杂多酸的效果相似,乙酸正丁酯酯化率≥%,选择性≥98%。虽然焙烧的作用可以减缓活性中心杂多酸流失,但酯化率有所下降;在相同反应条件下,焙烧的负载磷钨酸催化剂催化效果高于硅钨酸的。利用上述优化条件,合成了四种坡缕石负载型杂多酸催化剂(磷钨酸、硅钨酸、磷钼、磷钼钨),分别以正交试验法和单因素实验法,详细考察了各类负载杂多酸催化剂用量,酸醇摩尔比和反应时间等因素对合成柠檬酸三丁酯反应的影响。最佳实验条件下,四种催化剂中硅钨酸的催化性能最高,即:柠檬酸/正丁醇比为1:4 (摩尔比),,反应温度145℃,,%;从催化剂稳定性来看,负载型磷钼钨的催化活性最稳定,重复六次试验后,%,与首次酯化率相比仅降低10%;同时,发现江苏产坡缕石负载杂多酸的催化效果优于甘肃产坡缕石。此外,还尝试了坡缕石负载对甲苯磺酸催化合成柠檬酸三辛酯以及聚苯胺负载磷钨酸合成柠檬酸三异辛酯,结果表明,与坡缕石负载杂多酸稳定性的对比,聚苯胺不适合。关键词:坡缕石;负载杂多酸;柠檬酸酯;对甲苯磺酸;聚苯胺 Abstract In this dissertation, tributyl citrate was synthesized by citric acid and n-butanol, where the corresponding system of reaction of this kind of esterification was investigated. Catalytic capability for a series of catalysts made through alteration of four hetetopolyacids supported on palygorskite has been explored in detail. Other two reaction systems for makingtri-n-octyl citrate and trioctyl citrate are touched upon simultaneously. At first, the activity of the catalysts was examined in n-butyl acetate synthesis, which are used as detecting reaction catalyzed by tungstophorphosic and tungstosilicic acid supported on palygorskite, respectively. The conditions to make these heterogeneous catalysts were measured by orthogonal experimental design for optimal items, which displayed the result of the efficiency of the supported catalyst. It was found that the carrier treated by different acids led to similar activity when they were employed to support the same heteropolyacid and to catalyze the same reaction system. Then, the yield could reach ﹪with super selectivity above 98﹪under optimal conditions in the synthesis of n-butyl acetate. Desorption of active center such as heteropolyacids on carrier can be decreasedif being baked during making procedure but it was responsible for a relatively low conve