Screening of ionic liquids as extractant for 1-butanol extraction from dilute solution

Extraction of 1-butanol from dilute solution is one of the most popular means for bio-butanol recovery due to its low energy consumption and easy operation. However, the problems of low efficiency, solvent loss, extractant toxicity and etc. existed and needed to be solved by finding new extractant. Ionic liquids (ILs) as new material have been the potential extractants due to their special thermo-physical properties of negligible vapor pressure, high stability and strong designability. In this work, 960 ILs formed from 40 cations and 24 anions were evaluated for the selection of suitable extractant using COSMO-RS model with the index of distribution coefficient and selectivity. Finally, [HMIM][FEP] was screened out as a promising extractant for its high distribution coefficient (70.73) and selectivity (200.90). The LLE (liquid-liquid equilibrium) experiments of 1-butanol water + IL were determined and compared with the result calculated by COSMO-RS model. By comparison, it could be safely concluded that the calculated results were in good agreement with the experimental results generally, which meant the validation of this methodology. Meanwhile interaction energy calculations and hydrogen-bond (H-bond) interactions between 1-butanol or water and the selected IL were also investigated to reveal the working mechanism of the extraction process. (C) 2018 Taiwan Institute of Chemical Engineers. Published by Elsevier B.V. All rights reserved.