Ammonia → 4-Carbamoyl-2-nitrobenzoic acid

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Reaction Steps

This invention provides as new compositions of matter 2- and 3-nitroterephthalamic acids. This invention further provides a new process for the preparation of 2- and 3-nitroterephthalamic acids comprising the steps of reaction of a 1-4 carbon dialkyl nitroterephthalate with 20-51% by weight aqueous ammonia at 100°-200° C. under at least autogenous pressure for 1-6 hours at a dialkyl nitroterephthalate concentration of 10-40% by weight. Preferably 30-51% by weight aqueous ammonia is reacted at 150°-175° C. for 2-4 hours. For the preparation of 3-nitroterephthalamic acid it is preferred that the reaction be carried out using 20% by weight dimethyl nitroterephthalate and 25-51% by weight aqueous ammonia for 2-4 hours at 125°-175° C., most preferably at 150° C. 3-Nitroterephthalamic acid is isolated from the reaction mixture by cooling, removal of by-product nitroterephthalamide by filtration, adjustment of the pH of the filtrate to about 4 and removal of 3-nitroterephthalamic acid by filtration. For the preparation of 2-nitroterephthalamic acid, it is preferred that the reaction be carried out using about 10% by weight dimethyl nitroterephthalate and 25-51% by weight aqueous ammonia for 2-4 hours at 150°-200° C., most preferably at 175° C. 2-Nitroterephthalamic acid is isolated from the reaction mixture by cooling, removal of by-product nitroterephthalamide by filtration, adjusting the pH of the filtrate to about 4, removal of by-product 3-nitroterephthalamic acid by filtration, adjustment of the pH of the filtrate to about 2 and removing 2-nitroterephthalamic acid by filtration. The reaction may be summarized as follows: ##STR1##

Provenance & Evidence