Patent ID: 6933406

Claim:
A process for the preparation of 2-halo-6-nitrobenzoic acids of formula (I) wherein R 1 , R 2 , and R 3 , independently of one another, are hydrogen, fluorine, chlorine, bromine, nitro, or carboxyl, and Hal is fluorine, chlorine, or bromine, comprising heating a 2-halo-6-nitrobenzyl alcohol, ester, or ether of formula (II) or a mixture thereof, wherein R 1 , R 2 , R 3 , and Hal have the meanings given above for formula (I), and R 4 is hydrogen, C 1 -C 10 -alkyl, C 1 -C 10 -carbonylalkyl, or 2-halo-6-nitrobenzyl, in the presence of between 1 and 10 mol, per mole of alcohol, ester, or ether of formula (II), of nitric acid comprising between 35 and 90% by weight of water at a temperature between 50 and 200° C.