Experimental and molecular insights on the separation of indole from wash oil by tetraethylammonium‐based ionic liquids

Abstract

Abstract A method for separating indole (IND) from wash oil by tetraethylammonium‐based ionic liquid (IL) was proposed. The distribution coefficient and selectivity of 304 kinds of ILs to IND were predicted by using Conductor‐like Screening Model for the Segment Activity Coefficient model, and quaternary ammonium acetate ILs have excellent separation performance. The experimental conditions were validated, and the influence of these conditions was explored. The IL could be recycled with water, and its structure and performance remained unchanged after repeated use four times. The extraction efficiency for real wash oil provided by a company reached 91.6%. The structure–performance relationship was explored by using quantum chemistry and molecular dynamic simulation. A process combining liquid–liquid extraction and azeotropic distillation was established for the separation of IND mixtures, and an IND product with a purity of 99.9% was obtained. This work comprehensively analyzed the separation of IND from wash oil using ILs at an atomic‐molecular‐experimental‐process scale.