Patent ID: 7973192

Claim:
A process for the preparation of both hexamethylenediamine and aminocapronitrile by hemihydrogenation of adiponitrile, the process comprising: (a) forming a hydrogenate by the hemihydrogenation of adiponitrile in the presence of a strong base; (b) adding to the hydrogenate an amount of acid and/or of alkali metal or ammonium acid salt, wherein the amount of acid and/or of alkali metal or ammonium acid salt added to the hydrogenate is determined to provide a ratio T, determined by the following formula (I): T=[A]×n a /[M]×n b (I) in which: [A] represents the molar concentration of anion corresponding to the acid or to the acid salt, [M] represents the molar concentration of cation corresponding to the base present and to the acid salt, n a represents the charge number of the anion A, n b represents the charge number of the cation M, and T is greater than 1; (c) distilling the hydrogenate, which comprises an acid and/or an alkali metal or ammonium acid salt, and recovering a top fraction A, which comprises hexamethylenediamine, and a bottom fraction B, comprising aminocapronitrile, adiponitrile and high boiling point compounds.