杂多酸盐催化合成柠檬酸三丁酯研究

制备了1-（3-磺酸基）丙基-3-甲基咪唑磷钼酸盐（[MIMPS]₃PMo₁₂O₄₀）、1-（3-磺酸基）丙基-3-甲基咪唑磷钨酸盐（[MIMPS]₃PW₁₂O₄₀）和1-（3-磺酸基）丙基-3-甲基吡啶磷钨酸盐（[PyPS]₃PW₁₂O₄₀）3种杂多酸盐，用于催化柠檬酸和正丁醇合成柠檬酸三丁酯（TBC），考察了各催化剂的催化效果。其中，[MIMPS]₃PMo₁₂O₄₀具有最好的催化效果，在其催化下，考察了反应条件对酯化率的影响。结果表明：当醇酸物质的量比为4.5:1.0、反应温度为130℃、反应时间为3.5h、催化剂用量为柠檬酸质量的5%时，酯化率可达98.3%，且催化剂具有较好的重复使用性能，重复使用5次后，酯化率依然保持在94%以上。

Synthesis of Tributyl Citrate Catalyzed by Heteropolyacid Salt

Three kinds of heteropolyacid salts, i.e., 1-(3-sulfonic group) propyl-3-methyl imidazolium phosphomolybdate ([MIMPS]₃PMo₁₂O₄₀), 1-(3-sulfonic group) propyl-3-methyl imidazolium phosphotungstate ([MIMPS]₃PW₁₂O₄₀) and 1-(3-sulfonic group) propyl-3-methyl pyridine phosphotungstate ([PyPS]₃PW₁₂O₄₀), were synthesized.And the tributyl citrate (TBC) was synthesized with these three kinds of heteropolyacid salts as catalyst, in which [MIMPS]₃PMo₁₂O₄₀ performed the best catalytic property.The effects of various reaction conditions were investigated with [MIMPS]₃PMo₁₂O₄₀ as catalyst.The results showed that the esterification rate 98.3% was obtained under the optimum esterification conditions as follows: n(butanol):n(citric acid)=4.5:1.0, reaction temperature 130℃, reaction time 3.5h and the weight of catalyst 5%.The catalysis could be reused five times with the esterification rate still above 94%.