Capturing VOCs in the pharmaceutical industry with ionic liquids

1-ethyl-3-methylimidazolium acetate ([EMIM][Ac]) was adopted to absorb two common pharmaceutical volatile organic compounds (VOCs), dichloromethane (DCM) and ethanol. The vapor-liquid equilibrium experimental data of the VOC-ionic liquid (IL) systems were measured. The absorption experiment was carried out at 20 degrees C and at ambient pressure, with a gas flow rate of 1 L/min and an absorbent flow rate of 20 mL/min. The results showed that the removal ratios of DCM and ethanol reached 91.82% and 97.01%, respectively. Furthermore, the mechanism of IL capturing DCM and ethanol was systematically studied using the COSMO-RS model and a quantum chemical calculation. The results demonstrated that the separation capability of [EMIM][Ac] mainly depended on the strong [Ac](-)-VOC interaction. Finally, industrial-scale VOC capture processes were established and optimized. The results showed that IL process achieved a lower total heat duty and a higher increase in green degree compared with triethylene glycol process. (C) 2022 Elsevier Ltd. All rights reserved.