GB315400A - Manufacture of new dyestuffs - Google Patents

Abstract

315,400. Soc. of Chemical Industry in Basle. July 13. 1928, [Convention date]. Azo dyes are made (1) by treating with an oxidizing agent metal compounds of the dyestuffs o-oxy- or o-carboxyamine # J-acid, 2:8:6-acid or 1-sulpho J acid or o-oxy or o-carboxypolyazo dyestuffs containing these end components, or (2) by treating the above metal-free dyestuffs first with an oxidizing agent and then with compounds yielding metal. They dye cotton, wool and viscose silk generally in grey tints. In examples, (1) the dyestuff 4-chloro-2-aminophenol-6-sulphonic acid # J acid is treated with ammoniacal copper oxide and the product dried with free access of air; glycerine or an oxygen carrier may be added; (2) an ammoniacal solution of the copper compound of the dyestuff in (1) is oxidized by air in the presence or absence of an oxygen carrier, e.g. a copper or vanadium salt; (U) a caustic soda solution of the same copper compound is oxidized with potassium ferricyanide, an alkali perborate or persulphate, or lead peroxide; (4) an alkaline solution of the chromium compound of the dyestuff from nitrated 1-diazo-2-naphthol-4-sulphonic acid and J acid is oxidized with potassium hypochlorite; (5) the zinc compound of the dyestuff in 1 is oxidized with alkali hypochlorite; (6) the copper compound of the dyestuff 2-aminophenol-4: 6-disulphonic acid # J acid is oxidized in acetic acid with potassium bichromate; (7) a current of air is passed through a boiling ammoniacal solution of the copper compound obtained as in example 1; the oxidation may be effected under pressure above 100‹ C.; (8) the product obtained by oxidizing the dyestuff 4-nitro-2-aminophenol-6- sulphonic acid # J acid with alkali hypochlorite is converted into the copper compound. A table is given showing the shades produced from metalliferous dyestuffs using the following additional diazo components before and after oxidation with hypochlorite : 6-carboxy-4-sulpho-2- aminophenol, 4- and 5-nitro-2-aminophenol, 2- diazo-1-naphthol-4: 8-disulphonic acid, anthranilic acid, o-aminophenol-4-sulphonic acid, and the aminoazo product 4-chlor-2-aminophenol-6-sulphonic acid # (alkaline) J acid. Specification 296,680 is referred to. 6-Carboxy-4-sulpho-2-amino-1-phenol is made by sulphonating salicylic acid, nitrating and reducing. The Specification as open to inspection under Sect. 91 (3) (a) comprises also azo dyestuffs obtained (1) by treating metal compounds of azo dyestuffs in general with oxidizing agents and (2) by treating any suitable azo dyestuff first with an oxidizing agent and then with a metal compound. This subject-matter does not appear in the Specification as accepted.