Modeling of kinetics and stereoselectivity in liquid-phase α-pinene hydrogenation over Pd/C

The hydrogenation of a-pinene was investigated in a batch reactor over 4 wt% palladium on carbon (Pd/C) catalyst in temperature range of 50-90 degrees C and 2-11 bar of hydrogen pressure using n-octane as a solvent. The reaction network involves hydrogenation of alpha-pinene to two stereoisomers. The reaction kinetics was established in conditions free from diffusional limitations. The rate was temperature, pressure and reactant concentration dependent. Stereoselectivity was independent on conversion, but was sensitive to temperature and hydrogen pressure. A reaction network and mechanisms were proposed and corresponding kinetic equations were derived. The parameters of the mechanistic kinetic models were determined by using non-linear regression analysis. The kinetic models described the formation of the products with satisfying accuracy. (C) 2009 Elsevier B.V. All rights reserved.