Patent ID: 6160179
Filing Date: 2000-12-12
Classification: C07C

Abstract:
A method of synthesizing 4-nitro-m-phenylenediamine sulfate comprising the steps of:(a) diacetylating m-phenylenediamine by adding acetic anhydride to m-phenylenediamine at a temperature below 80.degree. C., thereafter adding water to form an aqueous diacetylating reaction mixture, and agitating said aqueous diacetylating reaction mixture for a sufficient period of time to form diacetyl-m-phenylenediamine precipitate;(b) nitrating diacetyl-m-phenylenediamine by dissolving diacetyl-m-phenylenediamine formed in step (a) in concentrate sulfuric acid, then reacting nitric acid with dissolved diacetyl-m-phenylenediamine, and forming 4-nitro-diacetyl-m-phenylenediamine precipitate upon adding water into nitrating reaction mixture;(c) hydrolyzing 4-nitro-diacetyl-m-phenylenediamine formed in step (b) with sulfuric acid in a mixed solvent of water and isopropanol, and forming 4-nitro-m-phenylenediamine precipitate upon neutralizing hydrolysis reaction mixture; and(d) sulfating 4-nitro-m-phenylenediamine by dissolving 4-nitro-m-phenylenediamine formed in step (c) in isopropanol, adding concentrate sulfuric acid at a temperature below 50.degree. C. to adjust pH of sulfating reaction mixture to about 2.0, heating said sulfating reaction mixture to temperatures from about 70.degree. C. to 75.degree. C., and forming 4-nitro-m-phenylenediamine sulfate salt.