| This paper studies the preparation of colloidal nickel and explores the effect of preparation conditions on catalytic hydrogenation of Cinnamaldehyde. Being stable in the air with high dispersion and narrow distribution,colloidal nickel catalyst is gained by reducing nickel ion with hydrazine in glycol at low temperature (<100℃) without the protection of N2. The optimal preparation conditions of colloidal nickel are determined by studying the fact which influences sizes and shapes of colloidal particles , such as reactant concentrations, pH values, reductant quantity, temperature, reaction time and mixing style. The optimal preparation conditions are: [Ni2+]=5.0×10-3 mol·L-1;[NaOH]=5.0×10-3 mol·L-1;[N2H4]=5.0×10-3 mol·L-1; reaction temperature -90℃;reaction time--3hr, adding Ni2+ solution dropwise to the mixture of NaOH and N2H4。Under the above optimal conditions, the influences of different solvents on preparation are studied and the results show that spherical colloidal nickel particles with good shapes are gained by adding appropriate quantity of high molecular polymer PVP([PVP monomer ]= 5.0×10-3 mol·L-1) . The prepared colloidal nickel catalysts was active in catalyzing hydrogenated reaction of Cinnamaldehyde. Meanwhile the catalytic activities of catalysts prepared on different conditions are compared. In addition, adsorption of Cinnamaldehyde on the Ni (100) surface by standing up perpendicularly to the surface was theoretically researched. Strong chemical interaction between Cinnamaldehyde and nickel cluster is observed. It is due to theσ-binding via the lone-pair electrons on the O atom, which is in favor of the catalytic hydrogenation of Cinnamaldehyde.
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