磷钨酸铵铝复合盐催化合成柠檬酸三丁酯

Synthesis of Tributyl Citrate Catalyzed by Mixed Salt of Ammonium and Aluminum Phosphotungstate

摘要:

制备了系列金属离子与NH4+复合掺杂磷钨酸盐催化剂，并将其应用于酯化合成柠檬酸三丁酯的反应中。其中，(NH4)0.5Al2/3H0.5PW12O40（I）的催化活性较高，且成本相对较低。在正丁醇与柠檬酸的物质的量之比为4:1，催化剂I用量1.5%，温度150℃，时间3h的反应条件下，柠檬酸三丁酯的收率达到97.1%。对催化剂I的元素组成、结构、表面酸强度与酸密度进行了表征。I的表面酸强度（H0）为-14.52~-13.75，表面酸密度为2.57 mmol/g，高于传统的单一掺杂磷钨酸盐。此外，经3次使用后，催化剂I的活性没有明显下降。

Abstract:

Metal ion and ammonium co-doped phosphotungstate were prepared and used as catalyst for the synthesis of tributyl citrate. Among them, (NH4)0.5Al2/3H0.5PW12O40 (I) showed relatively high catalytic activity and low cost. And the yield of tributyl citrate reached 97.1% with 4: 1 molar ratio of n-butanol to citric acid using 1.5% I as catalyst at 150oC in 3 h. The element composition, structure, surface acid strength and acid density of I were also characterized. The surface acid strength of I was in the range of -14.52 to -13.75, and the acid density of I reached 2.57 mmol/g, which was higher than that of traditional single cation doped phosphotungstate. In addition, the catalytic activity of I had no viewable change after 3 runs.