The application of Raney Nickel catalyst

The strong adsorption of hydrogen, the high catalytic activity and the thermal stability make Raney nickel widely used in many industrial processes and organic synthesis reactions. In addition to this, Raney nickel is largely insoluble in laboratory solvents other than inorganic acids and at the same time has a high density (similar to that of nickel, 6-7 g/cm³), both of which facilitate the separation of the catalyst from the mixture after the reaction.

1.Hydrogenation reactions
Raney nickel is mainly used for the hydrogenation of unsaturated compounds such as olefins, alkynes, nitrile, diolefins, aromatic hydrocarbons, substances containing carbonyl groups and even macromolecules with unsaturated bonds. Hydrogenation with Raney nickel sometimes does not even require the intentional addition of hydrogenation, as the reaction can be completed with only a large amount of hydrogen adsorbed in the activated Raney nickel. The reaction results in a cis-hydrogenated product. Alternatively, Raney nickel can be used for the reduction of heteroatom-heteroatom bonds.

Benzene is hydrogenated to cyclohexane by Raney nickel.

In this reaction benzene is reduced by hydrogenation to cyclohexane. Due to the special stability of aromatic compounds, direct hydrogenation reduction is difficult. However, the use of Raney nickel can speed up the reaction. Other non-homogeneous catalysts, such as those composed of platinum group elements, can achieve similar results, but are expensive to produce. The cyclohexane obtained after reduction can be oxidised to adipic acid, which is used as a raw material for the industrial production of polyamides such as nylon.

2.Desulphurisation
In addition to acting as a catalyst for hydrogenation, Raney Nickel will also act as a reagent in the desulphurisation of organic sulphur-containing compounds such as thioketones to hydrocarbons, thus enabling an indirect reduction pathway from carbonyl to methylene.