Short Compilation of Published Reaction Rate Data for Catalytic Hydrogenations in Supercritical Fluids.

Abstract

In this work, a short compilation is presented on heterogeneously catalyzed hydrogenations carried out in near-critical fluids. Reactions carried out in supercritical fluids, catalyzed by supported Pd, Ni or Cu, are considered as green processes in view of their negligible impact on the environment. A number of technologies are already available for clean hydrogenations, mostly performed in carbon dioxide as a dense solvent in continuous reactors. However, propane and other lower alkane solvents can perform as well as carbon dioxide but at much lower pressures. We review their behaviors in this paper in terms of observed reaction rates, space velocities, selectivities and apparent kinetic constants. In the case of vegetable oils, data are available on the effect of pressure and reaction conditions on the selectivity toward the preferred cis-isomer during linoleic hydrogenation.