1- 2-hydroxynaphthalene-3,6-disulfonic

Milling Red SWB l-[4-[4-[4-toluenesulfonyloxy]phenylazo](3,3 dimethyl-l,l -biphenyl)-4 -azo]-2-hydroxynaphthalene-6,8-disulfonic acid di-Na salt, Acid Red 114 [6459-94-5] M 830.8, m dec >250", Cl 23635, X,max 514nm. Salted out three times with sodium acetate, then repeatedly extracted with EtOH. [McGrew and Schneider J Am Chem Soc 72 2547 1950.] See Solochrome Violet R on p. 352 in Chapter 4. 

Modified PAN fibres containing aldehyde groups can be used to obtain chemically stained fibres. The chemical addition of dyes can be conducted following two schemes A) The fibres of the above composition are treated with aromatic amines, e.g., l-amino-8-hydroxynaphthalene-3,6-disulfonic acid ( H-acid ), and then azocoupling is carried out with a diazonium salt ... 

A particularly important class of coupling components are the aminohydroxy-naphthalenesulfonic acids. Appropriate variation of the disazo component permits the development of shades ranging from orange to black. Orange and scarlet are achieved with I-acid (6-amino-l-hydroxy-naphthalene-3-sulfonic acid) and y-acid (7-amino-1-hydroxynaphthaIcne-3-sulfonic acid), whereas H-acid (8-amino-l-hydroxynaphthalene-3,6-disulfonic acid) and K-acid (8-amino-l-hydroxy-naphthalene-3,5-disulfonic acid) derivatives are useful for red to bluish-red hues. Extremely lightfast red shades are also accessible with disazo dyes ( brown dyes ). For chemical structures see Section 3.1.5). 

An example is C. I. DirectBlack 166, 30026 [57131-19-8] (14). The first step is the acid coupling of 3,3 -diaminobenzanilide to l-amino-8-hydroxynaphthalene-3,6-disulfonic acid (H-acid), followed by alkaline coupling of aniline to the mono-azo dye and finally coupling of the disazo dye to w-phcnylenediaminc. 

In demethylative coppering to give the bis-copper complex 22 [74592-99-7] (3 Na, Li salt) [36], the sodium salt of the disazo compound made by coupling of bis-diazotized 3,3 -dimethoxy-4,4 -diaminodiphenyl with two equivalents of 8-amino-l-hydroxynaphthalene-3,6-disulfonic acid in alkaline medium is dissolved in water by adding diethanolamine. An ammonia alkaline copper(n) sulfate solution made from CuS04-5 H20 and of ammonia are added. The mixture is heated at 80-90 °C for 14 h. The solution is then cooled to 40 °C and the bis-coppered dye 22 salted out with sodium chloride. It dyes cotton in lightfast blue shades. 

Lissamine Green B l-[bis-(4,4 -dimethylaminophenyI)methyI]-2-hydroxynaphthalene-3,6-disulfonic acid sodium salt. Acid Green 50 [3087-16-9] M 576.6, m >200°(dec). Cl... 

The azo compounds are important chromophores because of extended electronic delocalisation between the two aromatic rings via the azo bond. The darkness of the dye is enhanced by extensive delocalisation combined with several sulfonic acid groups which function as auxochromes. An example is provided by Naphthol Blue Black B (10), prepared from 8-amino-l-hydroxynaphthalene-3,6-disulfonic acid (H-acid) (11) by coupling it in the 7-position with diazotised p-nitroaniline in acidic solution and subsequently coupling in the 2-position with diazotised aniline in alkaline solution (Scheme 3). The H-acid (11) is a very versatile component in dye manufacture because it can couple with diazonium salts in either the 2-position or 7-position depending on the pH of the reaction medium, as indicated in Scheme 3. 

Naphthalene Scarlet Red 4R [l-(4-sulfonaphthalene-l-azo)-2-hydroxynaphthalene-6,8-disulfonic acid tri-Na salt. New Coccine, Acid Red 18] [2611-82-7] M 604.5, m... 

Naicker KP, Jiang S, Lu FI et al (2004) Synthesis and anti-HIV-1 activity of 4-[4-(4,6-bisphenylamino-triazin-2-ylamino)-5-methoxy-2-methylphenylazo]-5-hydroxynaphthalene-2,7-disulfonic acid and its derivatives. Bioorg Med Chem 12 1215-1220... 

Naphthol. 6,8-disulfonic Acid. 7-Hydtox,y-1,3-naphthalenedisuljonic acid 2-hydroxynaphthalene-6,8-di-sulfonic acid G acid, Cl0H,O,S, mol wt 304,30. C 39.47%, H 2.65%, O 36.81%. S 21,0851), Prepd by heating 0 -naphthol with coned HjSCV 2 -naphthoi -3,6 -disulfonic acid (R acid) being obtained as a byproduct Fierz-David, Blangey ... 

EINECS 205-724-2 3-Hydroxynaphthalene-2,7-disulph-onio acid 2-Naphthol-3,6-disulfonic acid 2,7-Naph-thalenedisulfonic acid, 3-hydroxy-. Used as an azo dye intermediate. The disodium salt is used as a reagent to detect nitrogen dioxide in the air. Solid mp dec very soluble in H2O, EtOH, insoluble in Et20. 

Amino-5-hydroxy-2,7-naphthalenedisulfonic acid, monosodium 8-Amino-1-naphthol-3,6-disulfonic acid monosodium salt Ash acid EINECS 226-736-4 H acid monosodium salt 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, monosodium salt NSC 8632 Sodium hydrogen 4-amino-5-hydroxynaphthalene-2,7-disulphon-ate. 

A dye component that is used frequently is H acid (l-amino-8-hydroxynaphthalene-3,6-disulfonic acid). Production of this comparatively complex substitution pattern requires a series of different chemical reactions. The known side reactions and subsequent reactions on sulfonation and nitration of the naphthalene system and high-pressure hydrolysis of its substituents reduce the yield of the target product. If, as a consequence, intermediate isolations are unavoidable during the course of the process to prevent a gradual increase in the amount of by-products, additional product losses in mother and wash liquors will occur. Management of the often considerable quantities of solid waste and wastewater is therefore an important consideration in the production of H acid. 

Amino-l-hydroxynaphthalene-2,5-disulfonic acid (Cg H O NSg) 8-Amino-l-hydroxynaphthalene-3,5-disulfonic acid (Cg H O NSg) 8-Amino-l-hydroxynaphthalene-3,6-disulfonic acid (C H O NS )... 

Synonyms Cl 16255 Coccine Coccin red Cochineal Red A Food red 7 7-Hydroxy-8-[(4-sulfo-1 -naphthalenyl) azo]-1,3-naphthalenedisulfonic acid, trisodium salt 1,3-Naphthalenedisulfonic acid, 7-hydroxy-8-[(4-sulfo-1-naphthalenyl) azo]-, trisodium salt 1,3-Naphthalenedisulfonic acid, 7-hydroxy-8-((4-sulfo-1-naphthyl) azo)-, trisodium salt New coccine Ponceau 4R 1 -(4-Sulfo-1 -naphthylazo)-2-naphthol-6,8-disulfonic acid, trisodium salt SX purple Trisodium 1-(1-naphthylazo)-2-hydroxynaphthalene-4, 6,8-trisulfonate Classification Monoazo color azobenzene Empirical C2oHi4N2Na30ioS3 Properties M.w. 607.51... 

Synonyms Cl 18073 Disodium 5-(acetylamino)-3-((4-dodecylphenyl) azo)-4-hydroxynaphthalene-2,7-disulfonate 2,7-Naphthalenedisulfonic acid, 5-(acetylamino)-3-((4-dodecylphenyl) azo)-4-hydroxy-, disodium salt... 

The disulfonation of 2-naphthol leads to 2-hydroxynaphthalene-3,6-disulfonic acid (R-add) and 2-hydroxynaphthalene-6,8-disulfonic acid (G-acid), which are used in the production of dyestuffs such as Acid Red 26 and Acid Red 18. 

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