Patent GB-748233-A (GB)
Title: Improvements in the production of vat dyestuffs
IPC: C09B1/43
Filed: 1953-08-14
Abstract: 2,5-Dimethoxyterephthalic acid dichloride is prepared by methylating 2,5-dihydroxyterephthalic acid diethyl ester with methyl sulphate, saponifying the product with alcoholic caustic potash and heating the 2,5-dimethoxyterephthalic acid with thionyl chloride in nitrobenzene. 2,5 - Diethoxyterephthalic -, 4:6 - dimethoxy - isophthalic - and 2,3 - dimethoxy - terephthalic acid dichlorides are prepared by similar processes.ALSO:Vat dyestuffs are produced by heating a dialkoxy - meta - or para - dicarboxylic acid halide with a vattable aromatic amine or with two different aromatic amines of which at least one is vattable in order to form the corresponding acid diamide.  When at least one of the amines used is an amino compound of the anthraquinone series containing in the ortho-position to to the amino group a mercapto, hydroxyl or amino group or a halogen atom the amide formed may be converted into the corresponding azole in the same or a separate working operation.  Vattable amino compounds are those built up on the basis of anthraquinone, e.g., aminoanthra, quinones, amino-dibenzanthrone, aminoanthrapyrimidines and aminoanthraquinonebenzacridones.  One mol of the vattable amide may be reacted with the dicarboxylic halide and the product may be reacted with the same or another aromatic amine, e.g., aniline, the toluidines and the alkoxy anilines.  Dispersing agents or solvents for the reagents are chlorbenzene, dichlorbenzenes, trichlorbenzene or nitrobenzene. Acid binding agents may be employed such as sodium or potassium carbonate, sodium acetate or pyridines.  In examples: Dyestuffs are produced when 2:5 - dimethoxyterephthalic acid is heated in nitrobenzene with 1 - amino - anthraquinone, 1 - amino - 6 - chlor - or 1 - amino - 5 - methoxyanthraquinone (1); 1 - amino - 4 - or 1 - amino - 5 - benzoylaminoanthraquinone (2); in trichlorbenzene with 1 - mercapto - 2 - aminoanthraquinone, the product being a thiazole (3); in nitrobenzene with 4 - amino - 1.9 - anthrapyrimidine (4) and with - aminoanthraquinone - 2.1 (N) 11 21 (N) - benzeneacridone (5); 2.5 - diethoxyterephthalic acid dichloride is heated in nitrobenzene with 1-aminoanthraquinone (6); 1 - amino - 5 - benzoyl aminoanthraquinone (7) and 4-amino - 1.9 - anthrapyrimidine (8); and 4:6-dimethoxy - isophthalic acid dichloride is heated in nitrobenzene with 1-aminoanthraquinone (9); 1 - amino - 4 - or 1 - amino - 5 - benzoylamino - anthraquinone (10); 4 - amino - 1.9 - anthra - pyrimidine (11) and when 2.3-dimethoxy-terephthalic acid dichloride is similarly heated in nitrobenzene with 1-amino-anthraquinone (12); 1-amino-5-benzoylamino-anthraquinone (13) and 4-amino-1.9-anthrapyrimidine.  The dyestuffs are suitable for dyeing vegetable fibres, e.g., cotton and linen, and artificial silk and staple fibre from regenerated cellulose and mixtures of such fibres.  The dyestuffs maybe used as pigments or may be converted in a known manner into leucoester salts, e.g., of sulphuric acid and used in this form for dyeing and printing.  The dyestuffs are stated to have colours from yellow to orange and from red to blue.  The preparation of the alkoxy substituted phthalic, isophthalic and terephthalic chlorides employed as starting materials is described (see Group IV(b)).