A process for the hydrogenation of compounds comprising nitrile or nitro functional groups to amine, aminonitrile or aminonitro compounds is provided. The process can be a continuous process conducted in the presence of a heterogeneous hydrogenation catalyst in divided form and a basic compound. The reaction can be conducted in a stirred reactor comprising an external loop for circulating the reaction mixture, allowing one portion of the hydrogenated products to be separated without withdrawing the catalyst, by using tangential filtration. The process may be especially useful in the hydrogenation of adiponitrile to an aminocapronitrile/hexamethylenediamine mixture.