Catalytic hydrogenation of carbon dioxide to formic acid by transition-metal complexes

Conference · Fri Dec 31 04:00:00 EST 1993

OSTI ID:142021

Zhang, Junzhong; Li, Z; Wang, H; Wang, C ^[1]

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1. Taiyuan Univ. of Technology, Shanxi (China)

For the unfavorable effects of carbon dioxide on the environment and ecology and for the increasing scarcity of organic carbon carriers for the future, the study of conversion of CO{sub 2} into organic compounds is currently attracting widespread interest. The production of formic acid from the hydrogenation of carbon dioxide in alcohol by transition metals (Ru, Rh, Pd, Ir, Fe, Co, Ni) and their complexes as catalysts is reported. RuH{sub 2}(CO)(PPh{sub 3}){sub 3}, RhH(CO)(PPh{sub 3}){sub 3}, and IrH(CO)(PPh{sub 3}){sub 3}, have been found to be effective catalysts for the hydrogenation of CO{sub 2} in hydrogenation of CO{sub 2} in alcohol`s under mild conditions (loading pressures of CO{sub 2} and H{sub 2}, 2.5MPa each, and 333K) to provide formic acid. Ru and its complex RuH{sub 2}(CO)(Ph{sub 3}){sub 3} were shown to be most effective. Its activity reached at 40 mol HCOOH/mol cat-hr under conditions mention above. A catalytic cycle is proposed, which starts with formation of RuH{sub 2}(C)(PPh{sub 3}){sub 3} as the catalytic activity species, then CO{sub 2} insertion taking place to form metal-formate intermediate, and last releasing formic acid from metal center, either by reductive elimination of the hydrido formato ligands or ligand-assisted heterolytic splitting of dihydrogen with loss of formic acid.

• OSTI ID: 142021
• Report Number(s): CONF-930304--
• Country of Publication: United States
• Language: English

Related Subjects

40 CHEMISTRY
CARBON DIOXIDE
CATALYTIC EFFECTS
FORMIC ACID
HYDROGENATION
TRANSITION ELEMENT COMPLEXES