The kinetics of stereoselective hydrogenation of (-)-menthone and (+)-isomenthone mixture using nickel catalysts

The kinetics of the catalytic hydrogenation of optically active mixture of (-)-menthone and (+)-isomenthone was studied. Raney nickel and Ni/SiO2 were used as catalysts. Catalysts modified with tartaric acid (TA) were tested as well. Various isomers were produced in these reactions, especially (+)-n eomenthol and (+)-neoisomenthol. Small amount of (-)-menthol was produced, the yield of (-)-isomenthol was minimal. An isomerization, of(-)-menthone a nd (+)-isomenthone occurred during these reactions. Isomerizations among in dividual menthol isomers were not detectable under the given reaction condi tions. Based on the acquired experimental data, a kinetic model of the Lang muir-Hinshelwood type was created. This model was further continuously adju sted and simplified as to describe the experimental data and acquire optima l kinetic model parameters. (C) 2000 Elsevier Science B.V. All rights reser ved.