Homogeneous hydrogenation of aqueous hydrogen carbonate to formate under mild conditions with water soluble rhodium(I)- and ruthenium(II)-phosphine catalysts

Water-soluble rhodium(I)- and ruthenium(II)tertiary phosphine complexes wit h meta-mono-sulphonated triphenylphosphine (TPPMS) and 1,3,5-triaza-7-phosp haadamantane (PTA) as ligands catalyze the hydrogenation of aqueous HCO3- t o HCO2- under mild conditions. No amine additive is needed for good turnove rs. CO2 accelerates the reactions with [RhCl(TPPMS)(3)] catalyst; however, it slightly inhibits the reductions catalyzed by [RuCl2(TPPMS)(2)]. Bicarbo nate formed in the reaction of limestone with aqueous CO2 can also be used as starting material for formate production. Copyright (C) 2000 John Wiley & Sons, Ltd.