Chemical Equilibria in Formic Acid/Amine‐CO2 Cycles under Isochoric Conditions using a Ruthenium(II) 1,2‐Bis(diphenylphosphino)ethane Catalyst

The equilibrium position in formic acid/amine–CO2 systems has been examined as a function of pressure and temperature under isochoric conditions. The homogeneous ruthenium(II)‐1,2‐bis(diphenylphosphino)ethane catalyst was active in both reactions, that is, in formic acid cleavage producing pure hydrogen and CO2, as well as in carbon dioxide hydrogenation under basic conditions. High yields of formic acid dehydrogenation into H2 and CO2 are favored by low gas pressures and/or high temperatures, and H2 uptake is possible at elevated H2–CO2 pressures. These results take us one step closer to the realization of a practical H2 storage–discharge device.