Patent ID: 6469212
Filing Date: 2002-10-22
Classification: C07C

Abstract:
A process for separating 2,4-toluenediamine of a purity of at least about 96 wt % from a mixture of toluenediamine isomers comprising at least 2,4-toluenediamine and 2,6-toluenediamine and in which from about 60 to about 85 wt % of the mixture is 2,4-toluenediamine and from about 15 to about 40 wt % of the mixture is 2,6-toluenediamine, said method comprising:A) melting the isomer mixture, and then lowering the temperature of the mixture to a 2,4-toluenediamine nucleation temperature; B) gradually reducing the temperature of the mixture from the nucleation temperature to a temperature in the range of about 65 to about 70Â° C. such that the mixture is in the form of a solids phase enriched in 2,4-toluenediamine, and a liquid phase enriched in 2,6-toluenediamine; and C) separating these phases from each other.