GB387565A - Manufacture of dyestuffs - Google Patents

Abstract

Pigment dyestuffs are obtained by heating to about 150-300 DEG C., preferably in the presence of a high boiling solvent, a benzoquinone having the formula <FORM:0387565/IV/1> wherein A represents hydrogen, halogen, alkyl or aryl and B hydrogen or halogen, with an aromatic amine having the formula NH2-R-NXR<1> wherein X represents hydrogen or alkyl, R and R<1> aromatic residues which together with NX may form a carbazole ring and wherein one position ortho to the amino group is free. The reaction may be carried out in the presence of a metal chloride or an oxidizing agent, and an acid binding agent may be added when halogen halide is evolved. The dyestuffs, which may be used for dyeing wallpaper, on sulphonation are suitable for dyeing wool, silk, cotton, artificial silk, mixed fabrics, and paper. The sulphonic acids form barium, calcium and other lakes which may be used for colouring rubber, and with ammonia bases give dye pigments suitable for colouring nitrocellulose lacquers and acyl, e.g. acetyl, cellulose solutions. In examples: (1) 3-amino-N-ethylcarbazole is condensed in trichlorbenzene with chloranil; the dyestuff is sulphonated; (2) 3-aminocarbazole and also 3-amino-N-ethylcarbazole are condensed in trichlorbenzene with chloranil in the presence of sodium acetate and m-dinitrophenol; (3) p-aminodiphenylamine is condensed with phenyl-1 : 4-benzoquinone in trichlorbenzene and the resulting dyestuff sulphonated; (4) 3-amino-N-ethylcarbazole is condensed in nitrobenzene with 2 : 3 : 5 - trichlor - 6 - methyl - 1 : 4 - benzoquinone and the dyestuff sulphonated. According to a modification, similar dyestuffs are obtained by heating, in the absence of a sulphonating agent, to about 150-300 DEG C., a benzoquinone derivative having the formula <FORM:0387565/IV/2> wherein X1 represents alkyl or aryl, X2 hydrogen, halogen, alkyl or aryl, Y hydrogen or alkyl and R and R1 aryl residues which with the N1-Y group may form a carbazole ring, and wherein at least one ortho position to the NH group is free. In an example, 2 : 5-di-(N-ethylcarbazolylamino) 3-chlor-6-methyl-1 : 4-benzoquinone is heated in nitrobenzene solution and the resulting dyestuff sulphonated. The starting compounds used in this modification are prepared by heating the corresponding quinones and amines to a temperature somewhat below 150 DEG C. with or without a solvent. Specification 8886/12, [Class 2 (iii), Dyes &c.], is referred to. The Specification as open to inspection under Sect. 91 comprises also the condensation of 1 : 4-benzoquinones with any aromatic amino compound, and the ring closure of any 2 : 5-diarylamino - 1 : 4 - benzoquinones in which the 3, 6 positions are substituted by X1 and X2 as defined above. The following additional examples are given: (1) chloranil is condensed with aniline, m-chloraniline, and b -anthramine; (2) 1 : 4-benzoquinone is condensed with b -naphthylamine; (3) phenylbenzoquinone is condensed with p-aminodiphenyl; (4) toluquinone and ethylbenzoquinone are condensed with b -naphthylamine; (5) ring closure of 2 : 5 - di - (b - naphthylamino)-6-methyl - 1 : 4-benzoquinone is effected by boiling its nitrobenzene solution. This subject-matter does not appear in the Specification as accepted.