Efficient Separation of Methyl <i>tert</i>-Butyl Ether Using Ionic Liquids from Computational Thermodynamics to Process Intensification

Abstract

Ionic liquids (ILs) have been proposed as promising green solvents for the separation of azeotropes. In this work, the efficient separation of methyl tert-butyl ether (MTBE) from gasoline model oil using ILs was investigated from the molecular level (i.e., extraction mechanism) to process system integration (i.e., process simulation). The quantum chemistry (energy analysis and weak interaction) and molecular dynamics were implemented to explore the separation mechanism. Compared to benchmark organic solvents, 1-butyl-3-methylimidazolium nitrate ([BMIM][NO3]) and 1-ethanyl-3-methylimidazole hydrogen sulfate ([EMIM][HSO4]) had the highest extraction rate, and [NO3]− played a major role in the separation process. The extraction performance of MTBE from gasoline model oil using ILs was evaluated. [BMIM][NO3] had the highest extraction effect at 298.15 K. The efficient process of liquid–liquid extraction and extractive distillation with [BMIM][NO3] as an extractant were designed, which confirmed that ILs are promising extractants. This work provides a theoretical guideline to search and develop task-specific ILs for efficient recovery of MTBE.