Process for the preparation of 2-nitro-5-fluoro- or -5-chlorophenol

US5227535A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventors

• Ralf Pfirmann · Griesheim, DE
• Theodor Papenfuhs · Frankfurt, DE
• Klaus Forstinger · Kelsterbach, DE

Key dates

• Filing date: Oct 7, 1992
• Grant date: Jul 13, 1993
• Expiry date: Oct 7, 2012

Classification

• Technology area (CPC C): Chemistry; Metallurgy
• CPC primary: C07C201/12
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

The present invention relates to a process for the preparation of isomerically pure 2-nitro-5-fluoro- or -5-chlorophenol, by reacting 2,4-difluoronitrobenzene or 2,4-dichloronitrobenzene with aqueous alkali metal or alkaline earth metal hydroxide solution or suspension in the absence of organic solvents or other solubility promoting substances at temperatures from about 20.degree. C. to about 190.degree. C., adjusting the pH of the reaction mixture to about 1 to about 6 by the addition of acid, steam distilling the resultant product and isolating it from the distillate after cooling.