It is a special form of Nickel which comprises of finely divided spongy Nickel particles prepared by leaching out Aluminium under controlled conditions from a Nickel-Aluminium Alloy by treating the alloy in its powder form with a concentrated solution of caustic soda. The slurry of finely divided spongy Nickel particles so obtained is washed with large quantities of water till it is nearly free from free caustic. It is always kept submerged under water or a suitable solvent such as Ethanol, Cyclohexane, Dioxane etc. Raney Nickel is a versatile Hydrogenation Catalyst and is used in Hydrogenation of large number of functional groups notable among them being Carbon- Carbon double bond, Carbonyl (aldehydic and ketonic), Nitro, Azide, Nitrile, Oxime groups. It is also used in Hydrogenolysis (viz dehalogenation, debenzylation) and Desulfurisation reactions. Raney Nickel can also be used in hydrogenation reactions involving very high pressure and temperature. Due to its ability to hydrogenate virtually any type of functional group Raney Nickel is likely to hydrogenate most of the functional groups present on the molecule (of course to varying degrees) capable of getting hydrogenated . Raney Nickel is therefore termed as non-specific catalyst.
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