Efficient separation of oil–phenol mixtures and removal of neutral oil entrainment via an in situ deep eutectic method

Abstract

Traditional phenolic separation processes produce a large amount of wastewater and high neutral oil entrainment. This work used the COSMO model to predict the separation performance of deep eutectic solvents (DESs) for m-cresol (MCR) and identified a potential extractant EmimCl : MCR (1 : 0.4) DES and its liquid phase operating window. Partial MCR in direct coal liquefaction oil and EmimCl form a DES extractant and can be recycled. The density, viscosity and thermal stability of the extractant were determined experimentally, and the effect of experimental conditions on its separation performance was explored. The structure–activity relationship was explored through visualization of quantum chemistry and molecular dynamics simulation. The in situ DES extraction method and multi-stage flash evaporation combined with the distillation process could effectively remove neutral oil and reduce energy consumption as well as obtain 99.9% MCR product. The total annual cost of the new process was 38.8% lower than that of the traditional extractive distillation process.