Ionic liquids for highly efficient methyl chloride capture and dehydration

Abstract

AbstractA new methyl chloride (CH3Cl) capture and dehydration process using two ionic liquids (ILs) was designed and systematically studied. ILs [EMIM][Ac] and [EMIM][BF4] were screened out as CH3Cl capture and drying absorbents through the COSMO‐RS model. The result of solubility experiment suggests [EMIM][Ac] has an excellent solvent capacity for CH3Cl at mild operation conditions. The bench‐scale CH3Cl absorption experiments further confirmed the outstanding CH3Cl capture ability of [EMIM][Ac]. Besides, the water content of outlet gas can be decreased to 452 ppm (mass fraction) using [EMIM][BF4] in the dehydration experiment. The industrial‐scale CH3Cl capture and dehydration process was simulated and optimized. Compared to the benchmarked triethylene glycol process, IL process has higher product purity (99.99 wt%), and lower energy consumption. The quantum chemical calculations clearly revealed the relationship between hydrogen bond and separation performance. This study provides a decision‐making basis for designing green process associated with volatile organic compounds.