Preparation of 1,6-hexanediamine by hydrogenation of adiponitrile over a nickel catalyst under flow conditions

Summary

• 1. The effect of various factors on the hydrogenation of adiponitrile in a flow system under pressure was investigated.

• 2. It was shown that, under flow conditions with a sufficiently long layer of catalyst, adiponitrile is hydrogenated with formation of 1,6-hexanediamine In high yield (ranging to 80%).

• 3. The high.activity of the Raney nickel catalyst and the high ratio of the amounts of catalyst and of dinitrile undergoing hydrogenation make it possible to carry out the process under mild conditions (temperature 80°, pressure of hydrogen 50 arm).

• 4. Lowering of the temperature to 60° and of the pressure to 20 atm leads to a reduction in the yield of the diamine and an increase in the yield of the product of incomplete hydrogenation, 6-aminohexanenitrile, Raising the temperature and pressure favors side reactions and accelerates the deactivation of the catalyst.

• 5. Addition of 0.24% of sodium hydroxide to the dinitrile leads to a great reduction in the yield of diamine and to an increase in the yield of hexamethylenimine.