Process for the preparation of halogenated benzoic acids

US5481032A · kind A · utility

Assignee

• Hoechst GmbH · DE

Inventor

• Ralf Pfirmann · Griesheim, DE

Key dates

• Filing date: Nov 29, 1993
• Grant date: Jan 2, 1996
• Expiry date: Nov 29, 2013

Classification

• Technology area (CPC Y): Emerging Cross-Sectional Technologies
• CPC primary: Y02P20/582
• WIPO field: Organic fine chemistry
• WIPO sector: Chemistry

Abstract

A process for the preparation of halogenated benzoic acids of formula (1): ##STR1## in which R.sub.1, R.sub.2, R.sub.3, R.sub.4 and R.sub.5 are hydrogen, fluorine, chlorine or bromine atoms or C.sub.1 -C.sub.6 -alkyl, C.sub.1 -C.sub.6 -alkoxy, nitro, cyano, trifluoromethyl, aidehyde, C.sub.1 -C.sub.4 -alkoxycarbonyl, -SO.sub.2 -C.sub.1 -C.sub.4 -alkyl, -SO.sub.2 -phenyl, -CONH.sub.2, -CON(C.sub.1 -C.sub.4 -alkyl).sub.2, hydroxy, carboxy, -NH.sub.2 or -N(C.sub.1 -C.sub.4 - alkyl).sub.2 groups, at least one of the substituents R.sub.1 -R.sub.5 being one of said halogen atoms, which comprises reacting 1 mol of a benzophenone, asymmetrically substituted on the benzene rings A and B, of general formula (2): ##STR2## in which R.sup.1 -R.sup.10 are as defined above for R.sub.1 -R.sub.5, with about 1 to about 10 mol of an oxidizing agent selected from the group comprising hydrogen peroxide, urea/hydrogen peroxide addition product, an alkali metal peroxide, ammonium, alkali metal or alkaline earth metal peroxodisulfates, pertungstates, perborates or percarbonates, ozone, alkyl- or aryl-percarboxylic acids, alkyl- or aryl-persulfonic acids or persulfuric acid, at temperatures from about -20.…