Systematic Screening of Ionic Liquids for the Hydrogenation of Carbon Dioxide to Formic Acid and Methanol

Abstract

A systematic approach for the selection of suitable ionic liquids (ILs) for the hydrogenation of carbon dioxide (CO 2 ) to formic acid and methanol as the reaction media and extraction solvent is presented. This approach combines phase equilibrium, gas solubility/capacity, physical property estimation, and toxicity, along with a simple regeneration process. First, independent predictions of the liquid−liquid equilibrium (LLE) of the component mixture (methanol and formic acid + ILs), gas solubility of CO 2 in different ILs, and physical properties are estimated with the conductor-like screening model for real solvents. Then, a qualitative selection of the ILs that satisfied gas solubility and LLE-based routes was selected. In addition, the toxicity of ILs in the environment was also taken into account. Finally, the separation performance of the top IL candidates with their product mixtures in a continuous process was evaluated to identify process-based optimal solvents.

Carbon dioxide conversion technologies to formic acid and methanol promoted by ionic liquid.

“…The thermodynamic model for the CO2 solubilization and synthesis section is the conductor-like screening model for segment activity coefficient (COSMO-SAC) with Peng Robinson-Wong Sandler equation of state (ESPRWS). The reactor was modelled using RYield with two independent reactions (FA and MeOH formation) (Bello et al, 2021). The solubilization column was modelled using the rigorous vapour-liquid equilibrium with a two-outlet flash.…”