GB322209A - Improvements in the manufacture and production of azine derivatives - Google Patents

Abstract

322,209. Johnson, J. Y., (I. G. Farbenindustrie Akt.-Ges.). Aug. 27, 1928. Naphthazine derivatives.-The sulphonic acid derivatives of 1: 2-naphthophenazine and of 1 : 2 : 1<1> : 2'-dinaphthazine are converted to the corresponding hydroxy derivatives by heating with dilute caustic alkali solutions containing up to 10 per cent of caustic alkali. The reaction is preferably carried out under pressure and may be effected together with the production of the starting material in one operation. Generally, the use of the theoretical quantity of alkali is sufficient. In examples, the sodium salts of 1:2:1<1>:2<1>-dinaphthazine-8 : 8<1>- and 5: 5<1>-disulphonic acids and of 1 : 2-naphthophenazine-6- sulphonic acid (obtained from 1.2-naphthoquinone and o-phenylene diamine) are heated with dilute caustic soda lye to yield the corresponding hydroxy derivatives. The sodium salt of 2- naphthylamine-8-sulphonic acid is first heated with a solution of sodium hydroxide and hypochlorite and the resulting dinaphthazine, after further diluting the solution, is heated under pressure to give 8: 8<1>-dihydroxy-1: 2 : 1<1> : 2'-dinaphthazine. The Provisional Specification refers also to the treatment of any azine sulphonic acids with dilute caustic alkalis.