高酸值山苍籽核仁油合成生物柴油

Preparation of biodiesel from high-acid value litsea cubeba kernel oil

以高酸值山苍籽核仁油(LCKO)为原料,采用二步法合成生物柴油(BD),即先用固体酸SO42-/ZrO2为催化剂进行酯化反应降低酸值,再用相转移催化剂十六烷基三甲基溴化铵(CTMAB)/NaOH催化进行酯交换反应。酯化反应的最佳条件:质量分数4%的SO42-/ZrO2,醇油摩尔比10∶1,温度68℃,反应时间4h。原油酸值降到2.52mg/g;酯交换反应的最佳条件:温度25℃,质量分数0.5%的CTMAB,1%的NaOH,醇油摩尔比6∶1,反应15min。原油酯交换率达到97.6%。此工艺无酸化废水排放,不需耐酸设备,所需时间短,能耗少,成本低。以山苍籽核仁油为原料合成生物柴油,致力于找到一条经济的、绿色的生物柴油合成路线。

A two-step catalyzed process for synthesizing biodiesel （BD） by using high-acid value litsea cubeba kernel oil （LCKO） was investigated. LCKO was esterified with the methanol catalyzed by solid acid SO4^2-/ZrO2 to reduce acid value, and then the first reaction product was transesterified with the methanol catalyzed by the phase transfer catalyst of hexadecyl-tfimethyl-ammonium bromide （CTMAB）/NaOH. The results show that the optimal parameters of esterification are as follows： mass fraction 4% of SO4^2-/ ZrO2, molar ratio of methanol to LCKO 10： 1, temperature 68℃ and reaction time 4 h. Under such conditions, the acid value can decrease to 2.52 mg/g ; the optimal parameters of transesterification are as follows ： temperature 25 ℃, mass fraction O. 5% of CTMAB, mass fraction 1% of NaOH, molar ratio of methanol to LCKO 6：1 and reaction time 15 rain. The ester exchanging rate can reach 97.6%. By using this technology, it is featured by no acidic waste water discharge, no need for acid-proof equipment, short reaction time, less energy consumption and low cost. An economical and green route of synthesizing biodiesel was presented to make biodiesel from litsea cubeba kernel oil into industrialization.