Kinetic experiments and modeling of a three-phase catalytic hydrogenation reaction in supercritical CO2

The three-phase catalytic hydrogenation of an unsaturated ketone using supercritical carbon dioxide as a solvent was studied in order to simulate the performance of a semi-industrial trickle-bed reactor. High pressure kinetic experiments were carried out in a modified internal recycle reactor of Berty type. An industrial Pd on alumina supported catalyst was used, in form of egg-shell pellets. Data were collected over the whole conversion range, allowing for a thorough inspection of the reaction rate composition dependencies. It is shown that supercritical CO2 strongly increases the reaction rate. Experimental data sets were fit using both simple homogeneous power-law kinetics and complex heterogeneous Langmuir-Hinshelood models: here, the estimation of liquid concentrations was performed through vapor-liquid equilibrium calculations based on an equation-of-state approach. (C) 1999 Elsevier Science B.V. All rights reserved.