Hair Nitro Dyes

Also present but not essential in permanent hair colorants are nitro dyes which dye hair without oxidation. These dyes, nitro derivatives of aminophenols and benzenediamines, impart yellow, orange, or red tones. Although they have good tinctorial value, they are not as colorfast as the oxidative dyes. They also are used in semipermanent hair colorants. 

The nitro group is commonly encountered as a substituent in dyes and pigments of most chemical classes, but it acts as the essential chromo-phore in only a few dyes. Nitro dyes are a small group of dyes of some importance as disperse dyes for polyester and as semi-permanent hair dyes. Picric acid, 139, was historically the first nitro dye, although it was... 

Nitro dyes are the most important class of direct hair dyes they are substituted derivatives of nitrobenzene or nitrodiphenylamine [3, Nitro and Nitroso Dyes]. By proper selection of donor groups and substitution site on the benzene ring, a spectrum of dyes from yellow to blue violet can be prepared [9, pp. 247-250], [40] (Scheme 3). 

Nitro dyes are special because the small dye molecules penetrate the hair and impart color throughout the hair or in an annular pattern [41], In this way, intense colors can be obtained even in hair with a large proportion of white. The dyes are... 

The physical and chemical properties of dyes are very important for even coloring. First a hair dye should have comparable affinities for the roots, damaged areas, and tips. Second, the combined yellow-to-blue dyes used for shading must have similar properties so that color shifts will not take place when the hair is washed, for example. The importance of these problems is illustrated by the number of patent applications disclosing new, custom-tailored dyes [35] and suitable dye mixtures [42], The relatively good colorfastness and stability of some nitro dyes allow them to be used in oxidation hair dyes as well, especially for the shading of brilliant (mainly red) fashion colors. 

Among the chemicals which have been shown to be mutagens in Salmonella (as well as other short-term tests) that have recently been shown to be carcinogens are 1,2-dichloroethane (10 x 109 Ibs/year, U.S.), tris-dibromopropyl phosphate (the flame retardant used in children s polyester sleepwear), sulfallate (a pesticide), o-phenylene-diamine, 2,4-diaminoanisole (hair dye ingredient), 2-nitro-p-phenylenediamine (hair dye ingredient), and 4-amino-2-nitro-phenol (hair dye ingredient). 

Some Aromatic Amines and Related NItro Compounds—Hair Dyes, Colouring Agents and Miscellaneous Industrial Chemicals 1978 400 pages... 

The high toxicities of the nitro phenolic herbicides add to the difficulty of obtaining reliable teratogenicty data and probably account for the paucity of relevant studies in this area. However, studies of the hair dyes--l,2- and 1,4-diaminonitrobenzenes—revealed embryotoxicities and teratogenicities in this series (e.g, cleft palates, intrauterine growth retardation, resorption, blood vessel anomalies, reduced maternal and fetal weights, etc. (ref. 118, abstr. 751 and 752). 

Colorants for other purposes, such as hair dyes, are not so strictly regulated. The ones used in semi-permanent dyes are 2-nitro-i,4-diaminobenzene, (orange/red), 2-amino-4-nitrophenol (yellow), 1,4-diaminoanthraquinone (violet), and 1,4,5,8-tetra-aminoanthaquinone (blue), and a combination of these will produce the desired shade. 

Treatment of wool or hair with carbodiimides improves the wash fastness of applied dyes. The cosmetic qualities of bleached hair can be improved by treatment with N-cyclohexyl-N -(N-methylmorpholino)carbodiimide. N-ethyl-N -(3-trimethylammonio)propylcarbodiimide Axes the red dye 2-nitro-4[08-aminoethyl)amino]aniline to hair, most likely via an amide linkage. The coupling of a phosphorous dyestuff to cellulosic materials can also be accomplished using a carbodiimide. ... 

Nitro-2,4-diaminophenol, compd mentioned as an ingredient of hair dye. No other info is reported (Ref 4)... 

The hair dyes of Table 6-8 generally consist of neutral aromatic amine, nitro aromatic amine, or anthraquinone derivatives. They are all highly polar ingredients and can be classified as mono-, di-, or trinuclear (ring) dyes. Wong [38] has studied the kinetics of dye removal from hair for this type of hair dye and concluded that under all conditions the larger, trinuclear dyes rinse more slowly from hair than the smaller, mononuclear dyes. 

Hair Dyes 2-nitro-4-aminodiphenylamine and N-1-(2-Hydroxyethy )-2-nitro-p-phenylenediamine... 

Some Aromatic Amines and Related Nitro Compounds - Hair dyes. Colouring Agents and Miscellaneous Industrial Chemicals, lARC Monographs on the Evaluation of Carcinogenic Risks to Humans, Volnme 16, lARC, Lyon, France, 1978, p.325. 

CAS 6373-29-1 EINECS/ELINCS 228-922-0 Synonyms Benzenesulfonic acid, 3,3 -[sulfonylbis (2-nitro-4,1-phenylene) imino] bis [6-(phenylamino)-, disodium salt Cl 10410 Disodium 3,3 -[sulfonyl bis (2-nitro-4,1-phenylene) imino] bis [6-(phenylamino) benzenesulfonate Classification Nitro color Empirical C36H26NeNa20i2S3 Properties M.w. 876.81 Uses Dye for wool colorant in hair dyes Acid brown 14 Synonyms Cl 20195 Empirical C26Hi6N4Na20aS2 Properties M.w. 622.55 Uses Dye for wool, polyamide, and silk Manuf./Distrib. Aakash Chems. Dyestuffs http //members.aol.com/aakashchem/informati on.html, Aashiana Dyestuffs http //www.aashianadyestuffs.com, Albanil Dyestuff Int l. http //www.albanildye.com, Anar Int l. http //www.anarchem.com-, C. Lever Indo Colchem http //www.indocol.com, Trade-Search Assoc. 

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