氯化胆碱–乙二醇低共熔溶剂萃取煤焦油中酚类化合物机理探究

Exploration of the mechanism for the extraction of phenolic compounds in model coal tar by choline chloride:ethylene glycol deep eutectic solvents

深入研究低共熔溶剂(DESs)作为萃取剂萃取分离中低温煤焦油中酚类化合物的作用机理,对新型酚类化合物萃取剂的设计开发具有重要意义.本研究以氯化胆碱和乙二醇为例制备DES,采用热力学性质预测–萃取实验验证–作用机理探究的方法对DES–酚类化合物–正己烷体系萃取分离过程开展研究.结果如下:汉森溶解度参数(HSP)理论能够有效获取DES的溶解度参数,并准确预测酚类化合物萃取效率及相互作用关系.通过萃取实验验证了基于HSP理论的萃取效率预测,即苯酚>间甲酚>邻甲酚,结合量子化学分析手段从原子–片段的角度定量揭示了体系分离作用机制,证实氢键作用在萃取酚类过程中起主导作用,DES与酚类作用的体系主要是单中心和多中心氢键为主,形成的原子对作用强度更大.

For the design and development of new phenolic extractants,it is important to study the in-depth mechanism of deep eutectic solvents(DESs)as extractants for the extraction of phenolic compounds in medium-and lowtemperature coal tar.In this study,DES was synthesized using choline chloride and ethylene glycol.The extraction and separation process of the DES–phenol–hexane system was investigated using a combined approach of predicting thermodynamic properties,verifying the extraction efficacy through experiments,and delving into the underlying action mechanism.Our findings indicate that Hansen’s solubility parameter theory can adequately determine the solubility parameters of DES and accurately predict the relationship between extraction efficiency and phenol interaction.The predicted extraction efficiency based on HSP theory was confirmed by our extraction experiments,revealing the following order:phenol>m-cresol>o-cresol.To infer the separation mechanism of the system from an atomic fragment perspective,quantum chemical analysis was utilized.The study confirms that phenol extraction is primarily governed by hydrogen bonding,and the interaction system between DES and phenol is mainly dominated by single and multiple hydrogen bonding.Moreover,the intensity of the atom-pair interaction formed is considerable.