棉籽油间歇式酯交换反应动力学的研究

生物柴油(棉籽油甲酯)可以由棉籽油与甲醇在催化剂KOH存在下通过酯交换反应制得。故对棉籽油间歇式酯交换反应动力学进行了研究,并考察了反应温度和催化剂浓度对产物棉籽油甲酯浓度的影响。用液相色谱法分析棉籽油的组成;用气相色谱法分析产物中棉籽油甲酯的含量。由实验数据绘制的动力学曲线得到酯交换反应在开始阶段为准二级反应,以后紧接转为一级反应和零级反应,与文献报导的棕榈油酯交换反应动力学结果一致。由实验数据求出酯交换反应在开始阶段的动力学参数,35℃、45℃时的反应速率常数分别为0.9179Lmol-1min-1和1.049Lmol-1min-1,酯交换反应的活化能为10.88kJmol-1。根据实验结果得到棉籽油酯交换反应的最佳反应温度为45℃,最佳催化剂为1.1%KOH。

Kinetics of Cottonseed Oil Transesterification in a Batch Reactor

Methyl esters were produced by transesterification of cottonseed oil with methanol in the present of catalyst (KOH). The kinetics of transesterification was studied at various reaction times, temperature and catalyst concentrations. Samples were withdrawn quickly from the reactor with a pasteur pipet. The composition of the methyl esters was analyzed by gas chromatograph. The experimental data appear to be described by pseudo second-order model for the initial stages of the reaction and followed by first-order and zero-order-model, similar to those reported by Darnoko D and et al.5] Reaction rate constants for transesterification of cottonseed oil are 0.9179~1.049Lmol-1min-1.and activation energy of transesterification is 10.88kJmol-1.