Patent GB-721495-A (GB)
Title: An improved process for the production of water-soluble copper complex compounds of o.o-dihydroxy-azo or azomethine dyestuffs
IPC: C09B45/01
Filed: 1952-07-24
Abstract: Water-soluble complex copper compounds of o : o1-dihydroxy-azo or -azomethine dyestuffs are manufactured by treating o-hydroxy-azo or -azomethine compounds, containing no further hydroxy groups but at least one sulphonic acid group, in a slightly acid medium and in the presence of cupric ions or of copper metal at elevated temperatures with elementary oxygen in the presence of oxygen-transferring agents. When metallic copper is used, it may act both as oxygen-transferring agent and as the source of at least part of the necessary cupric ions, the reaction in this case being advantageously effected with the addition of a polynuclear quinone or a sulphonic acid thereof. Alternatively the oxygen-transferring agent may be a compound which readily forms a peroxide, e.g. aldehydes, hydrazones, hydrazo compounds, decahydronaphthalene or cumol or their sulphonic acids, or hydroquinone or pyrocatechol or their sulphonic acids.  The products may be used for dyeing leather or wool, and may also be freed from copper (e.g. by treatment with strong mineral acids or alkali metal sulphides) and the resulting free o : o1-dihydroxy compounds may be converted into other metal complex compounds, e.g. into chromium complexes in substance or on the fibre.  In examples: (1) air is led through a heated and stirred solution of the azo dyestuff p-nitraniline-->2 - naphthol-3 : 6-disulphonic acid, sodium acetate, copper sulphate and benzaldehydephenylhydrazone-4-sulphonic acid; the product is decoppered by boiling with hydrochloric acid, and the free o : o1-dihydroxyazo dyestuff may be chromed; (2) the azo dyestuff p-nitraniline-->2-naphthol-6 : 8-disulphonic acid is autoclaved with an aqueous solution of sodium acetate, copper sulphate and pyrocatechol-5-sulphonic acid with periodical renewal of the air in the autoclave; the product may be further treated as in (1); (3) the coupling component in (2) is replaced by 1 - phenyl - 3 - methyl - 5 - pyrazolone - 31-sulphonic acid and the oxygen transferred by decahydronaphthalene; (4) the azomethine dyestuff from m-nitraniline and salicylaldehyde-5-sulphonic acid is coppered as in (1); (5) the azo dyestuff p-nitraniline-->2-naphthol-3 : 6-disulphonic acid is treated as in (2) except that copper powder is used in place of the copper sulphate and pyrocatechol-5-sulphonic acid, and the sodium acetate is omitted; (6) part of the copper powder in (5) is replaced by copper sulphate, and sodium acetate is also added; (7) the process of (6) is effected in the presence of 2-ethylanthraquinone; (8) the dyestuff of (2) is treated as in (6), or with the further addition of anthraquinone-2-sulphonic acid; (9) the dyestuff of (3) is treated as in (6); the azo dyestuffs metanilic acid-->p-cresol, and p-anisidine-->1 : 4 : 8- or 2 : 3 : 6-naphtholdisulphonic acid may be similarly treated; (10) air is led through, and copper powder added to, a heated and stirred solution of the dyestuff of (4), sodium acetate, copper sulphate and anthraquinone-2-sulphonic acid; the product may be decoppered; (11) the diazo dyestuff 1 : 5-naphthylenediamine-3 : 7-disulphonic acid \sQnaphthol-4 : 8-disulphonic acid (2 mols.) is treated as in (6); (12) the diazo dyestuff benzidine\sQ1 - naphthol - 3 : 8 - disulphonic acid (2 mols.) is similarly treated.  Specification 660,447 is referred to.