Stagewise character of the hydrogenation of the double bonds of cyclopentadiene over raney nickel

Abstract

1. An investigation was made into the kinetics of the hydrogenation of cyclopentadiene in presence of Raney nickel at 25° and normal pressure in alcoholic and hydrocarbon solutions. 2. It was shown that cyclopentadiene is rapidly hydrogenated to cyclopentane in methyl, ethyl, and isobutyl alcohols. 3. In aromatic, hydroaromatic,aliphatic hydrocarbon solutions, cyclopentadiene is rapidly hydrogenated only as far as cyclopentene, and the second molecular proportion of hydrogen adds very slowly. 4. In all solvents examined, the conjugated double bands of cyclopentadiene are hydrogenated successively. In hydrocarbon solvents the two-stage character of the process can be demonstrated also by kinetic methods. 5. Both in alcohol and in hydrocarbon solvents cyclopentene can be obtained from cyclopentadiene if the hydrogenation is arrested after the Addition of one molecular proportion of hydrogen.