The use of hydride-forming rare-earth–cobalt intermetallic compounds in the dehydrogenation of propan-2-ol

Abstract

The dehydrogenation of propan-2-ol has been studied in the range 317–363 K in the presence of hydride-forming rare-earth intermetallics R₂Co₇(R = Pr, Nd and Sm). The use of these hydride-forming compounds is advantageous in the dehydrogenation reaction under mild conditions, since the formation of metal hydrides can change the unfavourable equilibrium in favour of dehydrogenation. The reaction proceeded quantitatively to form the hydride and acetone with a selectivity of nearly 100%. The surface activity of the intermetallics caused by the activation treatment has been discussed by means of an ESCA study. Co precipitated out on the alloy surface acts as a catalyst for the dehydrogenation, and detached hydrogen species migrate via these active sites to the underlying intermetallic phase to form the hydride by hydrogen spillover. Platinum-plated R₂ Co₇ prepared by reaction of R₂Co₇ in aqueous chloroplatinic acid exhibited catalytic properties superior to plain R₂Co₇.