Homogeneous transition metal catalysis: from the water gas shift reaction to nuclear waste vitrification

Abstract

A US–Hungarian cooperative research project between Professor R. Bruce King at the University of Georgia and Professor László Markó at the University of Veszprém during the period 1977 to 1986 was a major stimulus in extending the scope of Professor King’s research at the University of Georgia from synthetic transition metal organometallic chemistry to homogeneous catalysis. Since that US–Hungarian cooperative research project, a major emphasis of the work on homogeneous catalysis at the University of Georgia has been on applications of homogeneous transition metal catalysis to carbon monoxide, formate, and formic acid chemistry. This started with a joint project of Professor R. Bruce King with Professor Allen D. King Jr., which led to the discovery of an interesting mechanistic duality for the metal carbonyl-catalyzed water gas shift reaction (CO+H2O=CO2+H2) where use of M(CO)6 (M=Cr, Mo, W) catalyst precursors leads to a dissociative mechanism through formato metal carbonyl intermediates whereas use of an Fe(CO)5 catalyst precursor leads to an associative mechanism through metallocarboxylate intermediates. Subsequent scientific interaction of Professor R. Bruce King with Dr Charles M. King, then of the Westinghouse Savannah River Technical Center, led to a study of related formic acid reactions occurring during pre-treatment of nuclear wastes arising from catalytic activities of noble metal species in the wastes generated from uranium fission. Thus research at the University of Georgia during the period 1991–1994, supported through funding from the Savannah River and Hanford nuclear sites, led to the identification of a homogeneous nitrorhodium-catalyzed process for hydrogen liberation from formic acid with an apparent mechanism similar to the dissociative mechanism for the water gas shift reaction.