1- hydroxynaphthalene-4-sulfonic acid

However, when using hydrophilic counter-ions (e.g. Hydroxynaphthalene, sulfonic acids) 30) a decrease in retention is observed, because the ion pair becomes more hydrophilic in respect to the uncomplexed amine. Furthermore increased counter-ion concentration as well as a pH change prevent the dissociation of the ion pair. 

Naphthalenediol. This diol is prepared by the alkah fusion of 2-hydroxynaphthalene-6-sulfonic acid (Schaffer acid) at 290—295°C. Schaffer acid is usually produced by sulfonation of 2-naphthol with the addition of sodium sulfate at 85—105°C. This acid is also used as a coupling component in the production of a2o dyes such as Acid Black 26. 2,6-Naphthalenediol is used as a component in the manufacture of aromatic polyesters which, as is also tme of the corresponding amides, display Hquid crystal characteristics (52). 

Lower-sulfonated subsidiary colors of sunset yellow, among them 5-(phenylazo)-6-hydroxy-naphthalene-2-sulfonic acid (ANSC) and 4-[(2-hydroxynaphthalene-l-yl)azo]benzenesulfonic acid (BNSC), were determined by reverse-phase HPLC using Novapak Cl 8 and gradient elution with a water-tetrahydrofuran solvent system buffered with ammonium acetate (192). 

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). 

The most important coupling component for the Di—D and D 1- K<-D2 types is 6, which is produced by treatment of 6-amino-l-hydroxynaphthalene-3-sulfonic acid (I acid) with phosgene. 

Anilinesulfonic acids are chiefly used as starting component D, naphthylamine and Cleve acids as middle components Mi and M2, and I acid, its /V-phenyl derivatives, H acid, 2-amino-8-hydroxynaphthalene-6-sulfonic acid (y acid), and their derivatives as final component K. This type mainly possesses blue and green shades. Example C. I. DirectBlue 78, 34200 (16) [2503-73-3],... 

The synthesis of the 1 1 complex 8 is an example of [10] demethylative chroma-tion. It is prepared by diazotization of 5-amino-2-chlorohydroquinone dimethyl ether and coupling onto 1-hydroxynaphthalene-5-sulfonic acid. The reaction product and Cr203 in formic acid are heated in an autoclave at 130 °C. The chromium complex 8 [80004-31-5] is obtained as a black powder that gives grayish blue dyeings on wool and leather. 

In the stepwise synthesis of the unsymmetrical complex dye 13 [ 70236-60-1] [10], the azo dye made from diazotized l-amino-2-hydroxy-5-nitrobenzene and 1-phenyl-3-methyl-5-pyrazolone and the 1 1 chromium complex obtained from 6-nitro-l-diazo-2-hydroxynaphthalene-4-sulfonic acid and 2-naphthol are heated together at 80 °C for 5 h. The adduct is salted out with NaCl. A black powder is obtained that dyes wool and leather in dark brown shades. The resulting colors are fast, particularly on shrink-resistant wool. 

Alkaline glucose converts the diazonium salts of l-amino-2-hydroxy-naphthalene-4-sulfonic acid and its halogen, nitro, carboxyl, or sulfonic acid derivatives into the corresponding 2-hydroxynaphthalene-4-sul-fonic acids.126 According to this patent, the yields are nearly quantitative. 

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. 

Calmagite [l-(l-hydroxy-4-metbyl-2-phenylazo)-2-hydroxynaphthalene-4-sulfonic acid]... 

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 ... 

Cassella s acid EINECS 202-153-0 F Acid 2-Hydroxynaphthalene-7-sulfonic acid 7-Hydroxy-2-naphthalenesulfonic acid 7-Hydroxynaphthalene-2-sulphonic acid Mono Acid F Mono F Acid Monosuifonic acid F p-Naphthol-7-sulfonic acid 2-Naphthalenesulfonic acid, 7-hydroxy- 2-Naphthol-7-sulfonic acid 2-Naphthol, 7-sulfo- NSC 1704. Used as an intermediate for azo dyes. Crystals mp 89° soluble in H2O, EtOH, insoluble in CsHe, Et20. 

Naphthalenediamine and its derivatives are obtained by heating 4-aminonaphthalene-2-sulfonic acid with ammonia or an amine at 160-180° under pressure any sulfo groups in the other ring are unaffected. 4-Hydroxynaphthalene-2-sulfonic acid exchanges both its sulfo and its hydroxyl group.1198... 

Isolation of the sulfonic acids as salts is usually carried out in one of two ways. In one the sulfonation mixture is taken up in water, neutralized with slaked lime, and filtered from the precipitated calcium sulfate, whereafter the filtrate, which contains the calcium salt of the sulfonic acid, is treated with sodium carbonate which converts the calcium into the sodium salt after filtration from calcium carbonate the solution is concentrated until crystallization occurs or, if necessary, evaporated to dryness. This procedure, termed chalking in industry, can be applied to all sulfonic acids except for the few cases such as l-amino-4-hydroxynaphthalene-2-sulfonic acid that give sparingly soluble calcium salts however, it is inconvenient because of the large volumes of liquid that must later be evaporated to avoid this precipitation of... 

Transferrin Is believed (17) to bind iron(III) with three phenolate (tyrosine) residues and, being weakly acidic, proton interference Is responsible for the significant difference between 3 (10 ) and K ff (10 ). The phenolate group Is also present In seven of the fourteen structures In Figure 1, which is testimony to the particularly strong and selective affinity of this group for iron(III). Proton interference increases with the number of phenolate groups and in the case of the trls complex of 2,3-di-hydroxynaphthalene-6-sulfonic acid, proton interference reduces 33 by a factor of 10 . 

Calmagite [l-(l-hydroxy-4-methyl-2-phenylazo)-2-hydroxynaphthalene-4-sulfonic acid] [3147-14-6] M 358.4, m 300", pKi 8.1, pK2 12.4. A erode dye is extracted with anhydrous diethyl ether and forms red crystals from M62CO. It gives a red colom in H2O at pH 7—9 and a blue colom at pH 9—11 which turns red on addition of Ca + or Mg + ions. [Lindstrom Diehl Chem 32 1123 I960]. Complexes with Ca, Mg and Th. 

CAS 1658-56-6 EINECS/ELINCS 216-760-3 Synonyms Cl 15620 Ext. D C Red. no. 8 Fast red A 4-(2-Hydroxynaphthalen-1-ylazo) naphthalene-1-sulfonic acid, sodium salt 4-((2-Hydroxy-1 -naphthalenyl) azo)-1 -naphthalene sulfonic acid sodium salt 1-Naphthalenesulfonic acid, 4-((2-hydroxy-1-naphthalenyl) azo)-, monosodium salt Red no. 506 Rocceline Roccelline Solid red A Classification Azobenzene Empiricai C2oHi4N2Na04S Properties M.w. 401.41 m.p. 280 C Toxicoiogy Mutagen TSCA listed Storage Store in cool, dry place keep container closed when not in use... 

Diazon-8. See Polymethylene p-diazodiphenylamine sulfate 1 -Diazo-2-naphthol-4-sulfonic acid CAS 887-76-3 EINECS/ELINCS 212-958-9 Synonyms 4,4 -Azo-3-hydroxynaphthalene-1 -sulfonate 1-Naphthalenediazonium, 2-hydroxy-4-sulfo-, inner salt Empirical C10H6N2O4S Formula C10H5N2OSO3H Properties Yel. to brn. needles in paste or dry form si. sol in water m.w. 250.23 m.p. 160 C (dec.)... 

Hydroxynaphthalen-1 -ylazo) naphthalene-1 -sulfonic acid, sodium salt 4-((2-Hydroxy-1-naphthalenyl) azo)-1-naphthalene sulfonic acid... 

Sulfonation of 1-naphthol with sulfuric acid at 65 °C in nitrobenzene leads to l-hydroxynaphthalene-4-sulfonic acid (Nevile-Winther acid), which serves as a coupling component for azo dyestuffs such as Acid Orange 19. 

Hydroxynaphthalene-l-sulfonic add can be prepared by reaction of 2-naph-thol with chlorosulfonic acid at 0 °C in inert solvents such as o-dichlorobenzene or chloroethane. It is not available in satisfactory yields by the direct sulfonation of 2-naphthol with sulfuric add. Ammonolysis at 150 °C transforms 2-hydroxynaph-thalene-l-sulfonic acid into 2-aminonaphthalene-l-sulfonic acid (Tobias add), which, in quantity terms, is one of the most important derivatives of 2-naphthol. 

---