超声辅助环氧甲酯乙醇异构化反应动力学研究

Study on kinetics of the isomerization reaction of epoxy methyl and alcohol assisted by ultrasonic

以环氧生物柴油(即环氧脂肪酸甲酯)和无水乙醇为原料,固体酸式盐NaHSO_4为催化剂,分别在机械搅拌及超声辅助条件下进行开环反应,合成了可生物降解润滑油。考察了醇油摩尔比、反应温度、反应时间及催化剂用量等因素对开环反应的影响规律,得到了超声辅助下最佳工艺条件为:醇油摩尔比4∶1,反应温度70℃,反应时间8 h,催化剂用量(w)为1.5%,超声功率为50%。在单因素试验基础上,研究了机械搅拌与超声辅助下的乙醇-环氧生物柴油开环反应动力学,建立了开环反应的动力学模型,得到超声辅助条件下的开环反应活化能为39.16 k J/mol,频率因子为4.83×10~6h^(-1);与机械搅拌方式相比,超声强化开环反应条件更温和、反应速率更高,这与单因素试验的结论一致。

The biodegradable lubricants are prepared by using epoxy biodiesel （methyl esters of epoxy fatty acid） and anhydrous ethanol as raw materials, solid acid salt NaHSO4 as catalyst. The ring opening reaction is carried out under the conditions of mechanical stirring and ultrasonic-assisted respectively. The effects of the mole ratio of alcohol to oil, reaction temperature, reaction time and catalyst dosage on the ring opening reaction are investigated. The results show that the optimum process conditions for ultrasonic-assisted are as follows： the mole ratio of alcohol to oil is 4： 1, reaction temperature is 70 ℃, reaction time is 8 h, catalyst dosage （mass fraction） is 1.5% , and the ultrasonic power is 50%. Based on single factor experiments, the ring opening reaction kinetics of epoxy biodiesel-alcohol with mechanical stirring and ultrasonic-assisted are studied. In addition, the ring opening reaction dynamics models are set up. Under the condition of ultrasonic-assisted, the ring opening reaction activation energy is 39.16 kJ/mol, and the frequency factor is 4.83 × 10^6 h^-1. The conditions of opening reaction are more moderate and the reation rate is higher compared with the mechanical stirring method, which is consistent with the single factor experiment.