Patent GB-190302302-A (GB)
Title: Manufacture of Anthranilic Acid and its Derivatives.
Inventor: IMRAY OLIVER
Filed: 1903-01-30
Granted: 1903-11-26
Abstract: 2302. Imray, O., [Farbwerke vorm. Meister, Lucius, & Br³ning]. Jan. 30. Anthranilic acid; alkyl and aryl anthranilic acids, and their carboxylic and sulphonic derivations. -Consists in reacting with ammonia or primary fatty or aromatic amines upon o-halogen-benzoic acids or their salts in the presence of a small proportion of copper or a copper salt at a high temperature. Methylanthranilic acid is made by heating a mixture of potassium-o-chlorobenzoate or another alkali or alkaline-earth salt of o-chloro- or o-bromobenzoic acid, an aqueous solution of monomethylamine, and a small quantity of copper powder or a copper salt, in a suitable vessel under pressure to about 125‹ C. for 1-2 hours. The product is diluted, when cold, with water, and sufficient hydrochloric acid is added to redissolve the precipitate at first formed. After filtration, the methylanthranilic acid is precipitated by sodium acetate, and recrystallized from alcohol. Similarly, monoethylamine gives ethylanthranilic acid. These bodies melt at 179‹ and 152-3‹ C. respectively. If ammonia be substituted for the monoalkylamine, then, by the same process, anthranilic acid is obtained, besides some diphenylamine-di-o-carboxylic acid or phenylanthranilic - o - carboxylic acid ; the latter, being insoluble in water and dilute acids, remains undissolved when the product of the reaction is acidified, and may be filtered. The anthranilic acid is precipitated from the filtrate by sodium acetate. Similarly, with suitable modifications, phenylanthranilic acid or diphenylamine-ocarboxylic acid is produced when the amine is aniline, and the corresponding tolylanthranilic acid results when o- or ptoluidine is employed. Also alpha- and #-naphthylamine yield corresponding naphthylated anthranilic acids. Phenyl anthranilic acid melts at 183-4‹ C , and is slightly soluble in boiling water and copiously so in boiling alcohol. o- and p-Tolylantbranilic acids respectively melt at 188-9‹ and 191-2‹ C. ; alpha- and #-naphthylanthranilic acids melt at 205-6‹ and 208-9‹ C. If potassium anthranilate be the amino compound used, phenylanthranilic-o-carboxylic acid, melting at 300‹ C., is obtained ; if m- and pamido-benzoates are employed, phenylanthranilic-m-carboxylic acid or diphenylamine-di-o-m-carboxylic acid, melting at 281-2‹ C., and the corresponding p-carboxylic acid, melting at 282-3‹ C., are respectively obtained. Phenylanthranilic-p-sulpbonic acid or diphenylamine o-carboxylic-p-sulphonic acid results on using sodium sulphanilate with the alkaline o-halogenbenzoate ; the difficultly soluble acid sodium salt melts and decomposes at 865‹ C. If for the sulphanilate the salt of an isomeric or homologous aniline- or naphthylamine-sulphonic acid is substituted, one of a long series of isomeric or homologous phenylanthranilic-sulphonic acids or naphthyl-anthranilic-sulphonic acids is obtained; e.g., a naphthionate gives the 1-naphthylanthranilic-4-sulphonic acid or phenyl-alpha1-naphthylamine-o-carboxylic-alpha2-sulphonic acid, the acid sodium salt of which melts at about 200‹ C. If a #1-naphthylamine-alpha3-sulphonate is used, the 2-naphthylanthranilic-5-sulphonic acid or phenyl-#1-naphthylamine-o-carboxylic-alpha3-sulphonic acid is obtained, while #1-naphthylamine #3-sulphonic acid gives #1-naphthylanthranilic-#3-sulphonic acid or phenyl - #1 - naphthylamine - o-carboxylic-#3-sulphonic acid ; the respective acid sodium salts melt and do not melt at 290‹ C.