How is hexamethylenediamine made for manufacturing nylon-6,6?

Hexamethylenediamine, a key amine used in the production of nylon-6,6, is manufactured through the hydrogenation of adiponitrile.1

Adiponitrile itself is a dinitrile that can be produced from 1,4-dichlorobutane and sodium cyanide. Once obtained, the hydrogenation process converts the adiponitrile into the crystalline base hexamethylenediamine, which is then reacted with adipic acid to synthesize the nylon polymer.2314