Abstract: A mixture comprised of about 60-85% of 2,4-toluenediamine (2,4-TDA) and about 15-40% of 2,6-toluenediamine (2,6-TDA) is melted, the temperature of the mixture is lowered to a 2,4-TDA nucleation temperature, and the temperature of the mixture is gradually reduced from the nucleation temperature to about 65 to about 70° C. The resultant mixture is in the form of a solids phase enriched in 2,4-TDA, and a novel and useful liquid phase enriched in 2,6-TDA. These phases are separated. Preferably the solids are further purified by “sweating” them and removing the sweated liquid impurities. The sweated liquid can be recycled together with another charge of a mixture comprised of 2,4-TDA and 2,6-TDA. 2,4-TDA can be produced with a purity of 96-99%.
Type:
Grant
Filed:
March 20, 2000
Date of Patent:
October 22, 2002
Assignee:
Albemarle Corporation
Inventors:
John C. Prindle, Jr., Michael W. Easson, James Dee Palmer, Jason G. Jones, Max K. Mortensen, James E. Boone