Sponge
or skeletal metal catalysts (such as Raney-type hydrogenation
catalysts) are ubiquitous and extensively used in large-scale industrial
hydrogenation processes, including petrochemical refining, materials
manufacturing, and even food chemistry. Despite the many advantages
of these nonprecious metal catalysts, they are underutilized in smaller-batch
organic synthesis, including pharmaceutical manufacturing processes,
because of safety concerns. Here we describe a heretofore little known
deactivation procedure using aqueous sodium nitrate that renders the
spent catalyst safe to handle even when dry. During development of
a chemoselective nitrile reduction using a sponge cobalt catalyst,
we demonstrated that this procedure is much safer than other commonly
employed oxidative or acidic quenching methods. This procedure should
significantly improve the safety aspects of using these catalysts
in myriad settings, from lab-scale synthesis to manufacturing processes
for active pharmaceutical ingredients.