Multiscale Exploration and Experimental Insights into Separating Neutral Heterocyclic Nitrogen Compounds Using [emim][NO3] as an Extractant

Abstract

As valuable chemical materials, the heterocyclic nitrogen compounds are widely found in nature, and they are in common use. In this paper, the multiscale interaction mechanisms between 1-ethyl-3-methylimidazolium nitrate ([emim][NO3]) and representative heterocyclic nitrogen compounds (pyrrole and indole) during the extraction process are investigated. By combining theoretical and experimental research, first, the ionic liquid and its corresponding composite systems are studied with a multiscale microscopic method. With the help of quantum chemical calculation and molecular dynamics simulation, the polarity and the difference of the interactions of [emim][NO3] and nitrogen compounds as well as the mechanism of the separation process are explored. Additionally, the mechanism of the separation process and its effects are evaluated through phase equilibrium measurement and extraction experiment. The results reveal the highly selective separation of neutral pyrrole and indole and lay a solid foundation for the development of a new extraction process for complex systems containing neutral heterocyclic nitrogen compounds.