固体酸碱两步法催化麻疯籽油制备生物柴油反应过程的研究

Research on the preparation of biodiesel from jatropha oil by solid acid-base two-step catalyst process

以麻疯籽油为原料,对固体酸SiO_2/Zr(SO_4)_2-Ti(SO_4)_2、固体碱K_2CO_3/MgO-Al_2O_3两步法催化麻疯籽油制备生物柴油的反应过程进行研究,即第一步以固体酸为催化剂,催化麻疯籽油中的游离脂肪酸和甲醇预酯化,第二步以固体碱为催化剂,催化麻疯籽油与甲醇进行醇解反应。利用单因素实验及正交实验对固体酸碱两步法催化麻疯籽油制备生物柴油的反应过程进行优化。研究结果表明,固体酸催化预酯化的最佳条件为:催化剂用量2%,醇油摩尔比12:1,反应温度75℃,反应时间2 h,在此条件下酸值由10.47 mgKOH/g降为0.70 mg KOH/g。碱催化醇解反应的最佳条件为:催化剂用量为2%,醇油摩尔比为12:1,反应温度为65℃,反应时间2 h,醇解转化率稳定在95%左右。固体酸—碱两步法适用于催化麻疯籽油制备生物柴油,实验结果为实现麻疯籽油生物柴油的工业化生产奠定了一定的理论基础。

Two - step catalyzed process was used to prepare biodiesel from jatropha oil. The first step was that the free fatty acid from jatropha oil and methanol was pre - esterified by the solid acid catalyst SiO2/ Zr（ SO4 ）2 -Ti（ SO4 ）2 ;The second step was that alcoholysis reaction within jatropha oil and methanol was catalyzed by base catalyst K2CO3/MgO- Al2O3. The reaction conditions were optimized by single factor test and orthogonal test. The results showed that the optimal esterification conditions were with catalyst amount of 2%, the molar ratio of methanol to oil 12： 1, reaction temperature 75 ℃, reaction time 2 h, and the acid value reduced from 10.47 mg KOH/g to 0.70 mg KOH/g. The optimal alcoholysis reaction conditions were catalyst amount of 2%, molar ratio of methanol to oil 12： 1, reaction temperature 65 ℃, reaction time 2 h, and the alcoholysis conversion rate was around 95%. Two-step catalytic method was suitable for preparing biodiesel from jatropha oil, and the results laid some theoretical foundation for the industrial production of biodiesel.