Patent GB-491793-A (GB)
Title: Improvements in the manufacture and production of azo dyestuffs
IPC: C09B29/06
Filed: 1937-03-04
Abstract: Azo dyes; cellulose esters and ethers, dyeing and printing.-Azo dyestuffs are manufactured by coupling diazotized aromatic amines free from sulphonic acid groups with N-arylaminocarboxylic acids capable of coupling and having the general formula <FORM:0491793/IV/1> where X is hydrogen or an alkyl, substituted alkyl, cycloalkyl, aralkyl or aryl radicle, or a chain of several methylene groups connected with the aryl nucleus, and R is an alkylene radicle containing at least two methylene groups, e.g. b -N-arylaminopropionic acids, or b -N-arylamino-a - or b -methylpropionic acids, such as b -N-phenyl-, -(3-methylphenyl)-, -(2-methoxy-5-methylphenyl)-, -(2 : 5-dimethoxyphenyl)-, -(3-chlorophenyl)-, -(2-methyl-5-hydroxyphenyl)- or -(1- or 2-naphthyl)- aminopropionic acid, also b -N-alkyl-, (hydroxyalkyl-, alkoxyalkyl-, -acetoxyalkyl-, -halogenalkyl-, -cyanalkyl-, or -cycloalkyl-N-arylaminopropionic acids, such as b -N-methyl-, -hydroxyethyl-, -ethoxyethyl- or -hydroxyethoxyethyl-N-phenylaminopropionic acid, b -N-ethyl-, -hydroxyethyl- or -cyanethyl-N-(3-methylphenyl)-aminopropionic acid, b -N-n-butyl-N-(2-methoxy - 5 - methylphenyl) - aminopropionic acid or the addition products of several molecules of ethylene oxide to secondary N-arylaminocarboxylic acids of the said kind, also N - aralkyl - N - arylaminopropionic acids, such as b  - N - benzyl - N - phenylaminopropionic acid, or N-diarylaminopropionic acids, such as b -N-diphenylaminopropionic acids, or also N-aryl-N-alkylaminopropionic acids in which the alkyl radicle is a chain of methylene groups connected with the aryl nucleus, e.g. N - b  - carboxyethyl - 1 : 2 : 3 : 4 - tetrahydroquinoline or its 3-hydroxy-7-methyl-derivative or N-b -carboxyethyl-3 : 7-dihydroxy-1 : 2 : 3 : 4 - tetrahydronaphthoquinoline.  Suitable diazo components are aniline, o-chloraniline, 4 - aminobenzene - 1 - carboxylic acid and its methyl ester, 4-amino-1-acetylaminobenzene, 4 - aminophenyl - 1 - methylsulphone, 2 - aminobenzothiazole and a -naphthylamine, and particularly nitroarylamines, e.g. p-nitraniline, 2-chloro-4-nitraniline, 2 : 6 - dichloro - 4 - nitraniline, 6 - chloro- or -bromo - 2 : 4 - dinitraniline, 6 - cyano-2 : 4 - dinitraniline or 2-hydroxy-4-nitraniline; also aromatic amines already containing an azo group, e.g. 4-aminoazobenzene.  The products, in the form of their alkali salts, are suitable for dyeing and printing cellulose esters and ethers, and in the form of the free acids for dyeing textile materials prepared from cellulose esters and ethers, especially cellulose acetate artificial silk, with the aid of dispersing agents.  Examples describe the manufacture of the following dyestuffs: (1) p - nitraniline --> b  - N - hydroxyethyl - N-phenylaminopropionic acid, b -N-cyanethyl-N-(3 - methylphenyl) - aminopropionic acid or b  - N - phenylamino - a  - methylpropionic acid; the products dye acetate artificial silk red shades; (2) 2-chloro-4-nitraniline --> b -N-1-naphthylaminopropionic acid (violet shades); (3) 2 : 6 - dichloro - 4 - nitraniline --> b  - N-hydroxyethyl - N - (3 - methylphenyl) - aminopropionic acid; the product is mixed with a dispersing agent, e.g. dibutylnaphthalenesulphonic acid sodium salt or dried sulphite cellulose waste liquor, and then dried; (reddish brown shades); (4) 6-bromo-2 : 4-dinitraniline --> b  - N - methyl - N - (3 - methylphenyl)-aminopropionic acid (violet shades); (5) 4-aminobenzene - 1 - carboxylic acid methyl ester --> b  - N - phenylaminopropionic acid (red-yellow shades); (6) 3-chloro-4-aminophenyl - 1 - methylsulphone --> b  - N - (3-methylphenyl) - aminopropionic acid (orange shades); (7) 6 - methoxy - 2 - aminobenzothiazole --> b  - N - methyl - N - (3 - methylphenyl)-aminopropionic acid (rose-red shades); (8) 4 - aminoazobenzene --> b  - N - hydroxyethyl - N - (3 - methylphenyl) - aminopropionic acid (red shades); (9) p-nitraniline --> b -N-(2 : 5 - dimethoxyphenyl) - aminopropionic acid (blue-red shades); (10) 4-aminobenzene-1 - carboxylic acid --> b  - N - methyl - N-phenylaminopropionic acid (orange shades); (11) 6 - cyano - 2 : 4 - dinitraniline --> b -N-hydroxyethoxyethyl - N - (3 - methylphenyl)-aminopropionic acid (blue shades); (12) p-nitraniline --> N - b  - carboxyethyl - 3 : 7-dihydroxy - 1 : 2 : 3 : 4 - tetrahydronaphthoquinoline (blue shades). Specifications 252,240, [Class 15 (ii)], and 446,745 are referred to.  N - arylaminocarboxylic acids of the general formula given above are obtainable by adding on acrylic or methacrylic acid to aromatic primary or secondary amines or polynuclear heterocyclic nitrogen compounds hydrogenated in the ring containing nitrogen, e.g. by the process of Specification 478,304, or by the action of acrylic or methacrylic nitriles on the said amines followed by saponification with dilute mineral acid.  Reference is made in the examples to the reaction of aqueous acrylic acid with: N - hydroxyethylaminobenzene, N - o  - cyanethyl - 3 - methyl - 1 - aminobenzene, a  - naphthylamine (in the presence of alcohol), methylaniline, aniline, N-hydroxyethyl - 3 - methyl - 1 - aminobenzene, 2 : 5-dimethoxyaniline and 3 : 7-dihydroxy-1 : 2 : 3 : 4 - tetrahydronaphthoquinoline (in the presence of alcohol and caustic soda).  b  - N - hydroxyethoxyethyl - N - (3 - methylphenyl)-aminopropionic acid is obtainable by adding two molecular proportions of ethylene oxide on to N-(3-methylphenyl)-aminopropionic acid.