Acid Value Determination and Pre-Esterification of Crude Euphorbia lathyris L. Oil

There were various problems in the determination of oil acid value of the national standard method, and this paper developed a low cost, simple and effective way to determine the acid value of oil and grease. Furthermore, the esterification of high acid Euphorbia lathyris L. oil (ELO) with methanol could be efficiently catalyzed by hydrochloric acid to produce biodiesel, and the influencing factors such as the amount of catalyst, reaction time, reaction temperature and molar ratio of oil to methanol were also studied. Under the optimized conditions with the oil to methanol molar ratio of 1:30 and a reaction temperature of 70 ̊C, 95.8% oil conversion was obtained within 40 min in the presence of only 2.0 wt% of catalyst. Therefore, the low-cost non-edible Euphorbia lathyris L. oil as a raw material had good potential for the synthesis of biodiesel in industry.