Hydrochloric Acid → 3,5-Dichlorobenzoic acid

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Reaction Steps

206 parts of 2-amino-3,5-dichlorobenzoic acid is introduced into 1000 parts of water, then 180 parts of 50% by weight caustic soda solution and 70 parts of sodium nitrite are added and the mixture is allowed to flow while cooling into a mixture of 200 parts of water and 600 parts of concentrated hydrochloric acid (25% by weight strength). The mixture is stirred for another hour, 20 parts of urea is added and the whole is allowed to flow at 65°C with vigorous evolution of nitrogen into a mixture of 70 parts of methanol, 400 parts of water and 3 parts of copper(II) sulfate. The mixture is stirred for another 25 minutes, cooled to ambient temperature and suction filtered. 183 parts (96% of theory) of 3,5-dichlorobenzoic acid is obtained having a melting point of 179° to 181°C.

Provenance & Evidence