正丁基三乙胺硫酸氢盐离子液体催化制备油酸异丁酯

Preparation of oleic acid isobutyl ester catalyzed by n-butyl triethylamine hydrogen sulfate ionic liquid

采用正丁基三乙胺硫酸氢盐离子液体为催化剂,对油酸和异丁醇催化酯化合成油酸异丁酯的反应过程以及油酸异丁酯与生物柴油调合的低温流动性能进行了研究。单因素实验分析表明,当反应时间45 min,反应温度110℃,催化剂用量6%(占油酸用量的质量分数),醇酸摩尔比5∶1时转化率最高;正交实验极差分析表明,各因素对反应转化率的影响主次顺序为反应温度>催化剂用量>反应时间>醇酸摩尔比,反应的最佳条件为反应温度100℃,催化剂用量6%,反应时间45min,醇酸摩尔比5∶1。在最佳条件下进行验证实验,得到酯化反应转化率为98.6%。所得油酸异丁酯的凝点为-25.3℃,冷滤点为-21.5℃,运动黏度为6.52 mm2/s,其低温性能好,流动性能较差,与生物柴油调合可很好地改进生物柴油的低温性能和油酸异丁酯的流动性能。

The synthesis of oleic acid isobutyl ester by the esterification of oleic acid and isobutanol with n-butyl triethylamine hydrogen sulfate ionic liquid as catalyst and the low temperature fluidity of biodiesel blended with oleic acid isobutyl ester were studied. The results of single factor experiment showed that the conversion rate was the highest under esterification conditions of reaction time 45 min,reaction temperature 110 ℃,catalyst dosage 6%（ based on the dosage of oleic acid） and molar ratio of isobutanol to oleic acid 5∶ 1; the range analysis result of orthogonal experiment indicated that the effect of reaction temperature on conversion rate was the greatest,followed by catalyst dosage,reaction time and molar ratio of isobutanol to oleic acid; the optimal reaction conditions were obtained as follows： reaction temperature100 ℃,catalyst dosage 6%,reaction time 45 min and molar ratio of isobutanol to oleic acid 5∶ 1. The verification test was conducted under the optimal conditions,and the conversion rate was up to 98. 6%.The freezing point,cold filter plugging point and kinematic viscosity of oleic acid isobutyl ester obtained were-25. 3,-21. 5 ℃ and 6. 52 mm^2/ s respectively,which had good low temperature performance and poor fluidity. Both the low temperature performance of biodiesel and fluidity of oleic acid isobutyl ester improved when oleic acid isobutyl ester was blended with biodiesel.