Kinetics of linoleic acid hydrogenation on Pd/C catalyst

The hydrogenation of linoleic acid was investigated in semi-batch slurry reactors over 5 wt% palladium on carbon (Pd/C) catalyst in temperature and H-2 pressure ranges of 40-100 degrees C and 0.5-20 bar using n-decane as a solvent. The reaction network involves hydrogenation of linoleic acid to monoenoic acid isomers, predominantly oleic acid, and further hydrogenation of monoenoic acids to stearic acid. The reaction kinetics was established in conditions free from diffusional limitations. The rate was temperature and pressure dependent. 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 concentrations of linoleic acid, monoenoic acids, and stearic acid were used in parameter estimation. Data fitting allowed discrimination between rival mechanistic models, more specifically the influence of the hydrogen addition. The kinetic models described the formation of the products with satisfying accuracy. (C) 2008 Elsevier B.V. All rights reserved.