Structural changes during the leaching of copper-based raney catalysts

Abstract

Raney copper catalysts were produced by leaching pellets of two alloys containing 50 wt% Cu - 50% Al and 43 wt% Cu - 39 wt% Al - 18 wt% Zn in 20 wt% NaOH solutions. Changes in the surface area and pore structure were measured at temperatures from 1 to 50°C. It was found that prolonged contact of leached porous copper with caustic solution resulted in decreased BET surface area, increased pore diameters and increased copper crystallite sizes whilst the pore volume of the material remained constant. These changes, which have important consequences for Raney catalysts employed in fixed bed operation, occur through a dissolution reprecipitation process.