Nitriles homogeneous hydrogenation

Homogeneous hydrogenation of nitriles, Saturated nitriles are hydrogenated to primary amines in 67-100% yield with 1 as catalyst in THF. The catalytic activity of 1 for aromatic nitriles is not so high as for hydrogenation of aliphatic nitriles. The C=C bond of unsaturated nitriles is reduced more readily than the C=N bond. This catalyst is also eflective for dehydrogenation of amines (benzylamine — benzonitrile, 27% yield). 

So it became very surprising to see that the middle transition metal complexes 21-24 with Re(l) centers bearing chelate cw-diphosphine ligands were efficient catalysts in homogeneous hydrogenations of nitriles [75]. For instance, the hydrogenation of benzonitrile furnished the products dibenzylimine (PI), dibenzylamine (P2), and tribenzylamine (P3) with P2 as the major product (Scheme 27). Formation of benzylimine or benzylamine was not observed. Dibenzylimine was formed by the hydrogenation of dibenzylimine, while the... 

Rajesh K, Dudle B, Blacque O, Berke H (2011) Homogeneous hydrogenations of nitriles catalyzed by rhenium complexes. Adv Synth Catal 353 1479-1484... 

Wang H, Yang L, Rempel GL. Homogeneous hydrogenation art of nitrile butadiene rubber a review. Polym Rev. 2013 53 192-239. 

Alternatively, caprolactam can be produced from butadiene, via homogeneous nickel-catalysed addition of HCN (DuPont process) followed by selective catalytic hydrogenation of the adiponitrile product to the amino nitrile and vapor phase hydration over an alumina catalyst (Rhodia process) as shown in Fig. 1.49 [137]. 

Hydrogen reduction of organic nitrogen compounds occurs readily in the presence of homogeneous and heterogeneous catalysts, " , e.g., nitro, nitroso, oxime, nitrile, imine, hydrazone and azide compounds are reduced ... 

Nitriles have been hydrogenated at low temperatures and pressures over heterogeneou.s and homogeneous catalysts to produce amines, aldehydes, primary alcohols or alkanes. The reduction to produce amines is by far the most widely used transformation. The most commonly used catalysts are Raney nickel, Raney cobalt, nickel boride, cobalt boride, rhodium, palladium or platinum on various supports. Products formed in the hydrogenation of a nitrile (RCN) are determined by the fate of the intermediate... 

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