GB480602A - Manufacture of vat dyestuffs - Google Patents

Abstract

Vat dyes are made by condensing 1 : 4 : 5 : 8-naphthalenetetracarboxylic acid or a derivative or a substitution product thereof with an N - substituted o - diamine. According to examples, the tetracarboxylic acid is heated with (1) N-methyl-o-phenylenediamine to form a dyestuff similar to that described in the example given in the parent Specification; (2) 41-ethoxy-21-aminophenyl-dimethylurea to form a dyestuff with the same properties as those of the dyestuff of example 1 of Specification 265,232, [Class 2 (iii)]; (3) 21-aminodiphenylurea to form the same dye as in (1); (4) 1 : 4 : 5 : 8-naphthalenetetracarboxylic acid-2-dimethylsulphonamide is condensed with the urea of (3) (subdued red on cotton); (5) 2-sulphonephenyl-1 : 4 : 5 : 8-naphthalenetetracarboxylic acid or the corresponding anhydride is condensed with N-methyl-o-phenylenediamine (brown-red). Urea derivatives.-41 - Ethoxy - 21 - aminophenyl - dimethylurea is made by heating 1 - amino - 2 - nitro - 4 - ethoxybenzene with dimethylurea hydrochloride in an organic solvent and reducing. 21-Aminodiphenylurea is similarly made from 1-amino-2-nitrobenzene and phenylisocyanate. Naphthalene - 1 : 4 : 5 : 8 - tetracarboxylic acid derivatives.-1 : 4 : 5 : 8 - Naphthalenetetracarboxylic acid-2-dimethylsulphonamide is made by treating acenaphthalic acid with chlorsulphonic acid, condensing the sulpho-chloride with dimethylamine to form 2-sulphondimethyl-aminoacenaphthalic acid and oxidizing. 2-Sulphonephenyl - 1 : 4 : 5 : 8 - naphthalenetetracarboxylic acid is made by condensing the above sulphochloride with benzene and aluminium chloride and oxidizing.