Process for the preparation of 2,6-dichloro-4-nitroaniline

US4605767A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Otto Arndt · Hofheim, DE
• Theodor Papenfuhs · Frankfurt, DE

Key dates

• Filing date: May 16, 1985
• Grant date: Aug 12, 1986
• Expiry date: May 16, 2005

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C209/74
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

Process for the preparation of 2,6-dichloro-4-nitroaniline by chlorination of 4-nitroaniline with chlorine bleaching liquor in water using acids, which comprises chlorinating 1 mole of 4-nitroaniline in 3-6 moles of hydrochloric acid (HCl) or nitric acid (HNO.sub.3) in the form of a dilute, aqueous acid in the presence of a dispersing agent which is stable under the reaction conditions, the chlorination initially being carried out at 5.degree. to 10.degree. C. and then at 15.degree.-20.degree. C. and, finally, after 90-95% of the 2-chloro-4-nitroaniline intermediately formed has been converted into 2,6-dichloro-4-nitroaniline, the temperature of the aqueous suspension being increased from 15.degree.-20.degree. C. to 70.degree. C., without further addition of chlorine bleaching liquor, and then by post-chlorinating, by renewed addition of chlorine bleaching liquor, at temperatures between 20.degree. and 70.degree. C., bringing the pH of the aqueous suspension to 9.0 and filtering off the 2,6-dichloro-4-nitroaniline formed and washing it with dilute mineral acid.