油酸甲酯合成反应动力学研究

Reaction kinetics of methyl oleate synthesis

油酸甲酯是一种重要的化工原料,因现行生产工艺存在污染环境、腐蚀设备、反应转化率较低等问题,使其生产受到了一定制约,为此,提出了一种无催化"两步法"合成油酸甲酯的工艺路线。文中在"两步法"工艺路线的基础上进一步研究了油酸甲酯合成反应动力学。采用积分法分析了在293,298,303,308,313 K下的实验数据,结果表明二步反应均符合二级反应特征,反应遵循四面体机理,并得到了不同温度下的动力学方程式。根据得到的不同温度下的反应速率常数确定了二步反应的活化能分别为121.6 kJ/mol和115.2 kJ/mol,频率因子为2.76×1019和4.03×1018。在实验293—313 K温度范围内,通过实验对得到的动力学方程进行验证,得到的实验值与动力学方程计算值相符合,说明得到的动力学方程是可靠的,为"两步法"合成油酸甲酯的工业放大提供了理论依据。

Methyl oleate was an important chemical material,but the production was restricted by equipment corrosion,environmental pollution and low conversion. Non-catalyst two-step method was offered to synthesize methyl oleate. Firstly,oleic acid was reacted with thionyl chloride to obtain active oleoyl chloride,followed by the alcoholysis of oleoyl chloride with methanol to obtain methyl oleate. The kinetic equations for the two reactions were established. The kinetic experiments were carried out at 293,298,303,308,313 K,respectively. The experimental data at different temperatures were analyzed by the integral method. The results show that two steps of methyl oleate synthesis are a second order reaction both and the reactions follow tetrahedral mechanism. The frequency factors are 2. 76 × 1019and 4. 03 × 1018,and activation energies are 121. 6,115. 2 kJ/mol respectively for two reactions,which are obtained from the reaction rate constants at different temperatures by using the Arrhenius equation. The calculation data of the kinetic equations are in good agreement with the experimental data at 293-313 K,which shows that the kinetic equations are reliable and reasonable. It provides the basic data for the industrial development of methyl oleate.