Thermodynamic Analysis of CO₂ Hydrogenation to Ethanol: Solvent Effects

CO₂ hydrogenation to ethanol presents an important way to reduce CO₂ emissions and mitigate global warming. Since the solvent plays a key role in this reaction (i. e. in a batch reactor), the thermodynamics is investigated herein using an RGibbs model in Aspen Plus to illustrate the effects of solvents with various dielectric constant and vapor pressure. Accordingly, it is found that the solvents possessing a high dielectric constant together with low vapor pressure favor ethanol synthesis thermodynamically. Furthermore, mixing a solvent having a high-dielectric-constant and high vapor pressure with another solvent having a low-dielectric-constant and low vapor pressure promotes ethanol synthesis thermodynamically.