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

The equilibrium position in formic acid/amine–CO 2 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 CO 2 , as well as in carbon dioxide hydrogenation under basic conditions. High yields of formic acid dehydrogenation into H 2 and CO 2 are favored by low gas pressures and/or high temperatures, and H 2 uptake is possible at elevated H 2 –CO 2 pressures. These results take us one step closer to the realization of a practical H 2 storage–discharge device.