Patent GB-851861-A (GB)
Title: Improvements relating to heavy metal-containing azo dyestuffs and their use
IPC: C09B45/48
Filed: 1957-01-25
Abstract: The invention comprises dyestuffs of formula D1-M-D2 where M is a co-ordinative hexavalent heavy metal atom and D1 and D2 are coordinated mono- and dis-azo dyestuffs respectively.  The dyestuffs are made by adding, in a weakly acid, neutral to alkaline medium, a dicyclically metallising azo dyestuff to a dicyclically co-ordinated azo dyestuff which contains a co-ordinative hexavalent heavy metal atom, the dyestuffs being chosen so that the product contains both a mono- and a disazo dyestuff bound at the heavy metal atom.  They may also be made by metallising appropriate mixtures of monoand dis-azo dyestuffs.  Water-soluble textile dyestuffs are obtained if at least one of the dyestuffs contain at least one sulphonyl substituent but preferably the product does not contain more than one sulphonic acid group.  O, o1- dihydroxy-#s-carboxy -#s1- hydroxy and #shydroxy- #s1-amino-azo are the dyestuffs used although dye-stuffs containing a group convertible into a hydroxyl group during metallisation, such as #s-hydroxy- #s1- halogen or -alkoxydyestuffs, may also be used.  Chromium, cobalt and nickel are specified metals the former being preferred.  Metallisation is effected by conventional processes.  Indicated as mono-azo dyestuffs are the coupling products of diazotized #s-amino-phenols and -naphthols with acyl acetic acid arylamides, 5- pyrazolones, 2, 4- dihydroxyquinolines, benzene and naphthalene compounds coupling #s to a hydroxyl group and coupling products of diazotized #saminoaryl carboxylic acids with 5-pyrazolones or benzene and naphthalene compounds which couple #s to a hydroxy group.  Indicated as disazo dyestuffs are compounds formed from diazotized 4- or 5- arylazo -2-aminophenols and 5- pyrazolones or naphthols or phenols which couple #s to a hydroxy group, disazo dyestuffs having a metallizable group with m-dihydroxy or -diaminobenzenes or aminonaphthols as coupling components and those obtained from diazotized 4- arylazo -2- alkyloxy-1- naphthylamines and azo components coupling in an adjacent position to a hydroxy group.  Indicated as substituents for the dyestuff molecules are halogen, alkyl, alkoxy, nitro, acylamino, carboxy, sulphonic acid, sulphonamide, acyl and alkyl- and arylsulphonyl.  The metalfree dyestuff is added to the metal-containing dyestuff with components which are only partly soluble in water.  The addition is advantageously effected in aqueous solution at 40-95 DEG C. in the presence of alkaline agents or agents which buffer mineral acid.  The products are deep brown to black in colour.  The dyestuffs are used to colour wool, silk, leather, furs, casein, polypeptides, superpolyamides and -urethanes, paper, lacquers and cellulosic spinning masses. Examples and a Table are provided illustrating the preparation of the dyestuffs and their use in dyeing processes, representative of the monoazo dyestuffs used are 2-aminophenol -4- methyl sulphone --> 1- phenyl -3- methyl -5- pyrazolone, 4-nitro -2- aminophenol --> 3, 4- dimethyl phenol, 1- amino- 4- sulpho -6- nitro -2- naphthol --> 2-naphthol, 4- nitro -2- aminophenol --> 2- naphthol, 5- nitro -2- aminophenol --> 2- naphthylamine and 2- amino -1- carboxybenzene -4-sulphonic acid --> 2- naphthol, and representative of the disazo dyestuffs are 3- amino -4- hydroxyazobenzene -41- sulphonic acid dimethylamide --> 2- naphthol, 2- methoxy -4- nitro-aniline <FORM:0851861/IV (c)/1> 2- amino -5- naphthol <FORM:0851861/IV (c)/2> anthranilic acid, 4-amino -3- carboxy -41- chlorazobenzene --> 2-naphthol and 5- nitro -2- aminophenol --> 1-phenylazo -2- amino -snaphthol 7- sulphonic acid. Specification 791,438 is disclaimed.  Reference has been directed by the Comptroller to Specification 667,168.