Patent ID: 6900349
Filing Date: 2005-05-31
Classification: C07C

Abstract:
1. A process for preparing nitrobenzoic acids of the general formula (I) where each X is independently nitro, cyano, sulfonyl, carboxyl, carbonylphenyl, trifluoromethyl or trichloromethyl, each Y is independently phenyl, fluorine, chlorine, bromine or iodine and the phenyl radical, optionally substituted by up to 3 X and/or Y radicals other than hydrogen, m has the value 0, 1, 2 or 3 and n has the value 0, 1, 2 or 3, and the sum of m and n has the value 0, 1, 2, 3 or 4, from compounds of the general formula (II) where X, Y, m, n and also the sum of n and m are each as defined above for the general formula (I) and R is H or an OR′ radical and R′ is H, straight-chain or branched C or a radical of the general formula (IV), where X, Y, n, m, and the sum of n and m are each as defined for the general formula (I), comprising heating a mixture of nitric acid and water at a pressure in the range of 2-20 bar at temperatures in the range of 100-220° C. and metering the compound of the general formula (II) into the heated mixture of nitric acid and water, with the proviso that compounds of the general formula (II) exclude 2-halo-6-nitrobenzyl alcohols, esters or ethers of the general formula (V) and where R′ is as defined for the general formula (II), R Hal is fluorine, chlorine or bromine; wherein the maximum concentration of the compound of the general formula (II) in the reaction mixture as 7% by weight.