Patent ID: 9187403
Filing Date: 2015-11-17
Classification: C07C

Abstract:
1. A process for separating one or more aliphatic diamines from reductive amination reaction solvents and impurities comprising the steps of: feeding one or more cycloaliphatic cyanoaldehydes selected from the group consisting of 1,3-cyanocyclohexane carboxaldehyde, 1,4-cyanocyclohexane carboxaldehyde, mixtures thereof, and combinations thereof, hydrogen, ammonia, optionally water, and optionally one or more solvents into a reductive amination reactor system; contacting said one or more cycloaliphatic cyanoaldehydes, hydrogen, and ammonia with each other in the presence of one or more heterogeneous metal based catalyst systems comprise a metal selected from the group consisting of Co, Ni, Ru, Fe, Cu, Re, Pd, oxides thereof, mixtures thereof, and combinations thereof at a temperature in the range of from 80° C. to about 160° C. and a pressure in the range of from 700 to 3500 psig; thereby forming a product mixture comprising one or more cycloaliphatic diamines selected from the group consisting of 1,3-bis(aminomethyl)cyclohexane, 1,4-bis(aminomethyl)cyclohexane, combinations thereof, and mixtures thereof, one or more bicyclic amine by-products, optionally one or more cycloaliphatic aminonitriles, optionally one or more cycloaliphatic aminoalcohols, optionally one or more oligomeric by-products, ammonia, water, hydrogen, and optionally one or more solvents; removing said product mixture from the reactor system; adding a co-solvent for said one or more bicyclic amine by-products to said product mixture; removing at least a portion of said ammonia, said hydrogen, or mixture thereof from said product mixture via distillation; removing at least a portion of said water and said one or more optional solvents via distillation; removing at least a portion of said one or more bicyclic amine by-products via distillation; removing one or more optional cycloaliphatic aminonitriles, one or more optional cycloaliphatic aminoalcohols, and one or more optional oligomeric by-products via distillation; thereby separating said one or more cycloaliphatic diamines from said product mixture; wherein said distillation comprises employing a first distillation column, operating at pressure in the range of at least 200 mmHg to atmospheric, for removing at least a portion of said ammonia, said hydrogen, said water, said one or more bicyclic amine, and said one or more co-solvents; employing a second distillation column operating at pressure in the range of from 0.1 to 50 mmHg for removing aminonitriles, aminoalcohols, dimers, trimers; and employing a third distillation column, operating at pressure in the range of from 0.1 to 200 mmHg, for removing a low purity diamine fraction having greater than 85 weight percent diamine and high purity diamine fraction having greater than 99 weight percent diamine, and for removing of any bicyclic imine via a side-draw.