Shifting the equilibrium of methanol synthesis from CO2 by in situ absorption using ionic liquid media

Abstract

Renewable energy sources such as wind and solar power generate fluctuating electric energy. To bridge energy-lean times and to utilize the temporal surplus of electricity production large amounts of energy must be stored. One promising approach is the chemical storage in methanol that is formed from renewable H₂ from water electrolysis and CO₂. In our contribution we demonstrate a way to increase the methanol yields in CO₂ hydrogenation significantly by in situ sorption of methanol and water in alkali salt-doped ionic liquids (ILs). The reaction and product sorption take place in a single reactor vessel which shifts the methanol yield from the thermodynamic equilibrium of 25.3% at 75 bar (H₂ : CO₂ = 3 : 1) and 250 °C up to 60%.