Novel ZnX 2 -modulated Pd/C and Pt/C catalysts were developed to chemoselectively hydrogenate halogen-substituted nitroarenes, alkenes, benzyl ethers, and aromatic ketones.
Technetium / Nuclear waste / Fission products / Catalytic reduction / Hanford siteSummary. Pertechnetate ion ( 99 TcO 4 − , 10 −4 M) in alkaline solution is quantitatively reduced to hydrous TcO 2 by thermolysis (65 • C, 4 days) in the presence of organic complexants and fission-product noble metals (RuCl 3 , RhCl 3 , and PdCl 2 ; 0.001 M). Over 99% reduction occurs in the presence of ethylenediaminetetraacetic acid (EDTA), hydroxyethyl(ethylenediaminetriacetic acid) (HEDTA), or glycolic acid (0.050 M). Nitrilotriacetic acid (NTA), oxalic acid, and citric acid provide ≤ 2% reduction. Ruthenium, rhodium, and palladium chlorides also catalyze the reduction of TcO 4 − by hydrogen gas. The results are consistent with a two-step process of complexant degradation to generate H 2 , followed by catalytic reduction of pertechnetate to hydrous TcO 2 or soluble technetium complexes. Catalytic reduction is a viable, non-radiolytic route to the formation of non-pertechnetate species of 99 Tc in alkaline nuclear wastes, e.g., Hanford tank wastes.
Hydrogenation Hydrogenation O 0220 Novel ZnX 2 -Modulated Pd/C and Pt/C Catalysts for Chemoselective Hydrogenation and Hydrogenolysis of Halogen-Substituted Nitroarenes, Alkenes, Benzyl Ethers, and Aromatic Ketones. -Under the conditions presented, dehalogenation can be suppressed. -(WU*, G.; HUANG, M.; RICHARDS, M.; POIRIER, M.; WEN, X.; DRAPER, R. W.
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