Catalytic Performance Of Colloidal Nickel Catalyst In Acrylonitrile Hydrogenation

As a new type of catalytic material, colloidal nickel catalyst has some special properties in catalytic activity and selectivity. In this paper, the catalytic performance of colloidal nickel catalyst which is prepared by chemical reduction is studied .Firstly, preparation conditions of colloidal nickel are studied and influence of preparation conditions on catalytic hydrogenation of acrylonitrile is explored. In the absence of protective agent and nucleating agent, the pure colloidal nickel catalysts with high dispersion and narrow distribution are gained by reducing nickel ion with hydrazine in glycol. The effects of reductant quantity, pH values, reactant concentrations, temperature, reaction time and mixing style to the catalytic performance of colloidal nickel catalyst are reviewed. The optimal preparation conditions are: [N₂H₄]/[Ni²⁺] = 8, pH = 8～9, [Ni²⁺] =10 mmol/L, T = 90℃, 3 h, adding Ni²⁺ solution dropwise.Secondly, the substance, shape and size are respectively affirmed by UV-vis, XRD and TEM.Lastly, the effects of reductive reaction conditions such as H2 pressure, reaction temperature, acrylonitrile concentration and time on the catalytic performance of colloidal nickel which is prepared under the optimal conditions are investigated. Under the optimized reaction conditions of H2 pressure 5.0 MPa, 70℃, concentration of acrylonitrile 1.7 mol·L-1 and 3 h, conversion of acrylonitrile and selectivity of propionitrile achieve 96% and 100% respectively. Colloidal nickel displays good catalytic performance in the hydrogenation of acrylonitrile.