Raney R Type Nickel Catalysts from RSR Atomization of Al-Ni Powders
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RANEYR TYPE NICKEL CATALYSTS FROM RSR ATOMIZATION OF Al-Ni POWDERS
C. S. BROOKS, F. D. LEMKEY AND G. S. United Technologies Research Center,
GOLDEN East Hartford,
Connecticut,
ABSTRACT The synthesis and catalytic properties of hydrogenation catalysts of the RaneyR type derived from aluminum-nickel and aluminum-molybdenum-nickel RSR alloy powders have been evaluated. Two binary aluminum-nickel alloys, RSR 588, with 50 w/o Ni corresponding to currently available RaneyR commercial alloys, and RSR 587, with 28.5 w/o Ni corresponding to the proeutectic composition which produces exclusively Al 3 Ni as the precursor phase, were synthesized. One ternary, RSR 589, aluminum-molybdenum-nickel alloy with a nickel and molybdenum content to correspond to a commercial promoted R Raney alloy was prepared. The hydrogenation catalytic activity for six organic compounds representing diverse functionalities was measured in a bench scale batch liquid slurry catalytic reaction. Each catalyst was suspended in an agitated solution of the reaction (0.8 to 5M) at 22'C under a constant hydrogen over pressure of 0.86 atmospheres. A declining pressure technique was also used as a measure of catalytic activity where the catalyst was suspended in an agitated solution of the three reactants at 80°C at an initial hydrogen pressure of four atmospheres. The reactants selected consisted of acetone, nitrobenzene, itaconic acid, butyronitrile, toluene, and dextrose. The organic functionalities hydrogenated consisted of the conversion of: (1) Carbonyl to alcohol (2) Nitro group to amine group (3) Double carbon bond to a single carbon bond (4) Nitrile group to an amine group (5) Aromatic to a hydroaromatic ring (6) Aldehyde to an alcohol. RSR 587 catalyst, containing 28.5 w/o nickel, provides superior hydrogenation rates over bulk cast RaneyR nickel catalysts by factors ranging from 2 to 20 for selected reactions. Rapid solidification followed by heat treatment at 0 850 C of Al -42 w/o Ni powders yielded the greatest specific catalytic activity and provides a unique enrichment path for the formation of the peritectic phase, A1 3 Ni, and subsequently the most active skeletal nickel pore structure with the least amount of waste aluminum.
USA
06108
398 INTRODUCTION Catalytically active nickel, platinum, and rhodium skeletal structures which show promise of improved performance over commercial catalysts have been prepared from the chemical dissolution of directionally solidified and soluble gas atomized Al-Ni, Al-Pt, and Al-Rh eutectic alloys [1, 2]. After removal of the aluminum by caustic leaching, these alloys yield high surface area nickel, platinum, and rhodium fibers with demonstrated high specific catalytic activity in reactions such as hydrogenation of carbon monoxide to methane and steam reformation of a hydrocarbon (e.g., ethane) to hydrogen, plus carbon dioxide, as well as for the more conventional liquid phase hydrogenation reactions with organic functional groups such as those considered in this investigation. The present study is
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