Low temperature hydrogenation of 1- and 2-phenylethanols with noble metal catalysts in supercritical carbon dioxide

Catalytic ring hydrogenation of 1- and 2-phenylethanols was studied over several noble metal catalysts supported on charcoal or γ-alumina in supercritical carbon dioxide. The major products formed were corresponding cyclohexylethanols via aromatic ring hydrogenation of 1- and 2-phenylethanols while by products, ethylbenzene and cyclohexylethane were formed in minor quantities due to dehydroxylation reaction. A charcoal supported ruthenium catalyst gave the highest selectivity to (>80%) cyclohexylethanols among the other catalysts tested in this study at 323 K in supercritical carbon dioxide solvent.