Since the topic of oxime reduction has been brought up here, SWIM would like to ask a question about the catalytic hydrogenation of oximes/nitriles.
Using a nickel catalyst in EtOH saturated with NH3, oximes/nitriles are reduced to primary amines in good yields (JACS vol 66., pp. 876 (1944)). However, there is always going to be some amount of secondary amine in there. Ni catalyst is easier and cheaper than Pd/Pt which are used as you Rhodium describe in post
Post 450229
(Rhodium: "Catalytic Reduction of Nitriles and Oximes", Methods Discourse).
So is there a facile way of isolating the secondary amines from the primary, or is vacuum distillation of the base the only way to go? What about the solubility of secondary amine salts? - is fractional crystallization viable?
OH!!, what about enamine formation!? Primary amines recrystalllize just fine from acetone, but secondary amines react to form enamines. But SWIM doesn't know the solubility of these compounds either.
SWIM finds the oxime reduction in this post:
Post 360373
(Barium: "TMA-2 by low-pressure catalytic hydrogenation.", Methods Discourse), sort of hard to accept. No TLC was done on the final product to see how much secondary amine was in there, and an excess of base in the reaction was not used (just the base absorbed on the Ra-Ni).
Any thoughts on purifying without using vacuum distillation are welcome.