Reductive Amination of 2-, 3- and 5-Nonanones Catalyzed by Group 8-10 Metals

The reductive amination of 2-, 3- and 5-nonanones over platinum group metals, Raney Ni and Raney Co has been studied in ethanol in the presence of 9.3 molar ratio of ammonia to ketone at 50 °C and the hydrogen pressure of 8 MPa. With 2-nonanone, the major product was the corresponding primary amine over the metals other than Raney Ni. In contrast to the previous results with nonanal, no tertiary amine was found in the products; the secondary amine was also formed not at all (Pd, Ru, Rh, Raney Ni and Raney Co) or only to a slight extent (Os), except over Pt and Jr where it was formed in 17 and 16%selectivities, respectively. Over the catalysts other than Pd, Rh and Ir, the corresponding alcohol was formed in larger amounts than in the case of nonanal. In particular, over Raney Ni formation of the alcohol amounted to 54% which was even larger than the amount of the primary amine formed. Over Pd and Rh the alcohol was formed not at all or only slightly, and the primary amine was formed in 100 and 98%selectivities, respectively. In the presence of added ammonium acetate, the formation of alcohol and secondary amine was depressed, resulting in increased selectivities to the primary amine. Especially, the yields of primary amine increased to 100 and 98% over Raney Ni and Raney Co, respectively, in the presence of ammonium acetate. 3- and 5-Nonanones were less reactive than 2-nonanone with Pd, Pt, Rh and Ru, the reactivity decreasing in the order: 2->3->5-nonanone. In contrast, the selectivity for the formation of alcohol increased in the reverse order: 2-