功能化离子液体选择性萃取尼古丁的研究及DFT计算

Study on selective extraction of nicotine by functionalized ionic liquid and DFT calculations

针对传统工艺使用有机溶剂萃取烟草及其副产物中的尼古丁对人体及环境产生了巨大危害的问题,以功能化咪唑类离子液体为萃取剂,萃取烟草净油中的尼古丁,探究离子液体的阳离子侧链官能团对尼古丁萃取效果的影响。使用量子化学计算的方法计算不同功能化离子液体与尼古丁的结合能,分析了离子液体与尼古丁的相互作用。结果表明:离子液体侧链官能团对尼古丁与离子液体的相互作用具有位阻效应,位阻越小,离子液体与尼古丁的结合能越大,对尼古丁的萃取率越高,离子液体[HOEMIm][BF_(4)]对尼古丁的萃取率最高(97.2%)。此外,从分子角度分析了[HOEMIm][BF_(4)]与尼古丁及3种主要杂质(新植二烯、十六酸乙酯和亚麻酸)的相互作用,发现[HOEMIm][BF_(4)]与尼古丁的结合能为42.0 kJ/mol,远大于该离子液体与3种杂质的结合能(分别为15.3、10.1、20.9 kJ/mol)。将[HOEMIm][BF_(4)]作为萃取剂,不仅对尼古丁具有高萃取率和良好的萃取选择性,而且避免了挥发性有机溶剂的使用,降低了对人体和环境的危害。

The traditional process uses organic solvents to extract nicotine from tobacco,which has caused great harm to human body and environment.In this work,functionalized imidazolium ionic liquids were used as extractants to extract nicotine from tobacco absolute.The influence of cationic side chain functional groups of ionic liquids on the extraction of nicotine was investigated.At the same time,the binding energy of different functionalized ionic liquids with nicotine was calculated by quantum chemical calculation,and the interaction between ionic liquids and nicotine was analyzed.The results show that the ionic liquids side chain functional group has a steric hindrance effect on the interaction between nicotine and ionic liquids.The smaller the steric hindrance is,the greater the binding energy of ionic liquid and nicotine is,and the higher the extraction rate of nicotine.The extraction rate of nicotine by[HOEMIm][BF_(4)]is the highest,about 97.2%.In addition,the interaction of ionic liquid[HOEMIm][BF_(4)]with nicotine and three main impurities(neophytadiene,ethyl hexadecanoate and linolenic acid)is analyzed from a molecular perspective.It is found that the binding energies of[HOEMIm][BF_(4)]with the three impurities 15.3,10.1,20.9 kJ/mol,respectively,while that with nicotine is 42.0 kJ/mol.It is much larger than the binding energy of the ionic liquid with three impurities.The research content of this paper shows that using ionic liquid[HOEMIm][BF_(4)]as extractant not only has high extraction rate and good extraction selectivity for nicotine,but also avoids the use of volatile organic solvents and reduces the harm to human body and environment.