ABSTRACT
The heterogeneous catalyst, Raney™ nickel, deactivates during the hydrogenation of adiponitrile. The present study shows that the deactivation process is general to a, (1}-dioitriles of varying length and also occurs for 6aminocapronitrile but does not occur with mononitriles such as butyronitrile. In contrast to a previously reported mechanism for Ni catalyst deactivation in acetonitrile hydrogenation, these reactivity trends implicate deposition of oligomeric secondary amines and thus blocking of active sites as the mechanism of deactivation. Electron spectroscopy for chemical analysis (ESCA) reveals an increase in C and N on deactivated samples compared to nondeactivated samples and supports the conclusions drawn from reactivity studies.
