2-hydroxynaphthalene = 3-naphthol

Supplement to b) 2-Hydroxynaphthalene ((3-naphthol) is obtained from naphthalene. The reaction sequence includes sulfonation of the starting material at 150-160°C and subsequent alkaline baking of the intermediate sodium naphthalene-2-sulfonate with sodium hydroxide at 300 to 320°C for 6 to 8 hours. After the reac-... 

Naphthalenol. 1-Naphthol, a-naphthol, or l-hydroxynaphthalene/P(9-/j5 -iJ forms colorless needles, mp 96°C, bp 288°C, which tend to become colored on exposure to air or light. It is almost insoluble in water, but readily soluble in alcohol, ether, and benzene. 1-Naphthol and 2-naphthol are found in coal tar (56). 

Naphthalenol. 2-Naphthol or p-naphthol or 2-hydroxynaphthalene/7i3 -/5 -i7 melts at 122°C and boils at 295°C, and forms colorless crystals of characteristic, phenoHc odor which darken on exposure to air or light. 2-Naphthol [135-19-3] is manufactured by fusion of sodium 2-naphthalenesulfonate with sodium hydroxide at ca 325°C, acidification of the drowned fusion mass which is quenched ia water, isolation and water-washing of the 2-naphthalenol, and vacuum distillation and flaking of the product. A continuous process of this type has been patented (69). The high sulfate content ia the primary effluent from 2-naphthol production is greatiy reduced ia modem production plants by the recovery of sodium sulfate. 

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). 

Benzoxepins require drastic conditions for the thermal rearrangement to naphthols. When 3-benzoxepin-2,4-dicarboxylic acid is heated to 300 C, a decarboxylation reaction takes place and 3-hydroxynaphthalene-2-carboxylic acid (10) is formed in 44% yield.91... 

Hydroxy-3-naphthoic acid ( BONA or BON ) is prepared by heating the sodium salt of 2-hydroxynaphthalene with carbon dioxide in a pressure chamber at 240 to 250°C at a pressure of 15 bar (Kolbe synthesis). The reaction mixture is continuously agitated. Remaining 2-naphthol is separated and recycled ... 

The same chemistry is involved as with monoazo yellow pigments, except that (3-naphthol pigments are obtained by coupling with 2-hydroxynaphthalene ((3-naph-thol) instead of acetoacetarylides. They have the general chemical structure ... 

H-Naphtho[2,l-fe]pyrans (1.19) with an amino or alkoxy residues in the 6-position (1.30) show particularly high colourability. The 1-amino- and l-alkoxy-3-hydroxynaphthalenes (1.28 and 129) required for the synthesis of these compounds are prepared from 2-naphthol as illustrated in Figure 1.9. ... 

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. 

SYNS BASF URSOL ERN C.I. 76605 C.I. OXIDATION BASE 33 DURAFUR DEVELOPER D FOURANENE ERN FOURRINE 99 FOURRINE ERN FURRO ER a-HYDROXYNAPHTHALENE 1-HYDROXYNAPHTHALENE NAKO TRB 1-NAPHTHALENOL O-NAPHTHOL TERTRAL ERN URSOL ERN ZOBA ERN... 

Hydroxynaphthalenes, which are called naphthols are readily accessible from the naphthalenesulfonic acids by heating them to fusion with solid alkali. They are also available from coal tar. 

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. 

The 1-nitroso-2-naphthol and the 2-nitroso-l-naphthol have been studied by H and C NMR. In an early study Vainiotalo and Vepsalainen suggested that l-nitroso-2-hydroxynaphthalene exist at the trans form 51C. For the latter both the oxime and the nitroso (51A) form were suggested based on H and C NMR in CDCI3. However, in a recent study Ivanova and Enchev ° assigned the two different sets of resonances to two different rotamers of the oxime form, i.e. 51B and 51C. They also measured solid... 

Apart from PAR, many other azo reagents have been applied as spectrophotometric reagents for indium. l-(2-Pyridylazo)-2-naphthol (PAN) has been applied widely as analytical reagent for indium [24,36-38]. The indium chelate with PAN is extractable into chloroform from solutions of pH 6 (e = 1.9-10 ). Indium has also been determined with PAN by derivative spectrophotometry [39]. Other azo reagents proposed for indium include 2-(2-pyridylazo)-l-hydroxynaphthalene-4-sulphonic acid [40], TAR (formula 4.7) [41], Lumogallion (e = 5.4-10 at 510 nm) (formula 21.1) [42], Sulpharsazen [43], Thoron I [44], and Eriochrome Black T (extraction into n-butanol in the presence of diphenylguanidine, = 3.6-10 ) [45], Picramine M [46], 2-(2-thiazolylazo)-p-cresol (TAC) [47], and 2,4,6-tris(2-hydroxy-4-sulphonaphthylazo)l,3,5-triazine (e = 8.4-10 [48]. 

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. 

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. 

Synonyms cas 135-19-3 2-naphthol 2-hydroxynaphthalene isonaphthol 2-naphthalenol developer... 

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