Kazunori Tanaka, Y. Takagi, O. Nomura
Oct 1, 1974
Citations
0
Influential Citations
40
Citations
Journal
Journal of Catalysis
Abstract
Abstract Cyclohexanone and one of its methyl-substituted derivatives (2-, 3-, or 4-methylcyclohexanone) were hydrogenated competitively in pairs in cyclohexane solvent at 30 °C over group VIII metal catalysts. All of the methyl-substituted ketones were less reactive than cyclohexanone. The reactivity of a methylcyclohexanone relative to cyclohexanone was dependent upon the reaction mechanism and the atomic radius of the catalyst. INDO calculations, on the other hand, revealed that the carbonyl groups of the substituted and unsubstituted ketones are nearly identical in charge distribution and bond order, thus suggesting that the methyl substituent effect upon the hydrogenation rate is due primarily to steric hindrance to adsorption.