单体酸组成分析及在生物柴油方面的应用

单体酸甲酯化后用气相色谱．质谱联用仪测定单体酸的主要组成，共鉴定出硬脂酸（32．72％）、十八烯酸（25．53％）、肉豆蔻酸（12．16％）、棕榈酸（8．51％）等15种物质。用单体酸为原料制备生物柴油的方法为：单体酸与甲醇在对甲苯磺酸催化作用下，进行酯化反应来获得脂肪酸甲酯。考察了甲醇与单体酸的摩尔比、催化剂浓度、反应时间以及反应温度对酯化率的影响。结果表明，最佳酯化反应条件为：醇酸摩尔比3：1，对甲苯磺酸用量6％，反应时间3h，反应温度60℃。在此条件下，单体酸酯化率达98％，实验所得生物柴油的主要性能指标符合ASTN质量标准，并接近O#柴油性质。

Components analysis of monomer acid and application in biodiesel

The main components of monomer acid were determined by GC/MS. Fifteen components （such as stearic acid ,oleic acid ,myristic acid and palmitic acid） were identified. The results showed that the octadecanoic acid content accounted for 32.72%, the octadecanoic acid reached 25.53 %, the tetradecanoic acid content arrived at 12.16% and the hexadecanoic acid was 8.51%. With p-toluenesulfonic acid as catalyst, the production technology of biodiesel from monomer acid was elaborated. The results showed that the optimum reaction conditions of esterification were molar ratio of monomer acid with methanol 3 ： 1, toluene sulfonic acid content 6%, reaction time 3 h, reaction temperature 60℃. In these conditions, the conversion rate of biodiesel with monomer acid reached 98%. The main performance indicates that it was in line with the standard of ASTM, and closed to the O# properties of diesel fuel.