| Identification | Back Directory | [Name]
2-Naphthol-6,8-disulfonic acid | [CAS]
118-32-1 | [Synonyms]
-Naphthol-disulphonicacid
β-Naphtholdisulfonic acid
2-NAPHTHOL-6,8-DISULFONIC ACID
NAPHTHOL-6,8-DIPOTASSIUMDISUFONATE
7-hydroxy-3-naphthalenedisulfonicacid
7-Hydroxy-1,3-naphthalenedisulfonicacid
2-Hydroxynaphthalene-6,8-disulfonicacid
7-hydroxynaphthalene-1,3-disulfonic acid
7-hydroxynaphthalene-1,3-disulphonicacid
1,3-Naphthalenedisulfonicacid, 7-hydroxy-
2-NAPHTHOL-6 8-DISULFONIC ACID ( G SALT )
7-hydroxynaphthalene-1,3-disulfonic acid hydrate
TIANFUCHEM--High purity 118-32-1 2-Naphthol-6,8-disulfonic acid | [EINECS(EC#)]
204-245-6 | [Molecular Formula]
C10H8O7S2 | [MDL Number]
MFCD00021514 | [MOL File]
118-32-1.mol | [Molecular Weight]
304.3 |
| Raw materials And Preparation Products | Back Directory | [Preparation Products]
ACID RED 114-->disodium 7-hydroxy-8-[[4'-[[4-[[(p-tolyl)sulphonyl]oxy]phenyl]azo][1,1'-biphenyl]-4-yl]azo]naphthalene-1,3-disulphonate-->Aluminium, 7-hydroxy-8-[(4-sulfo-1-naphthalenyl)azo]-1,3-naphthalenedisulfonic acid complex-->Reactive Orange 125-->Chromate(5-), bis(8-((5-((diethylamino)sulfonyl)-2-(hydroxy-kappaO)phenyl)azo-kappaN1)-7-(hydroxy-kappaO)-1,3-naphthalenedisulfonato(4-))-, tetrasodium hydrogen
-->1,3-Naphthalenedisulfonic acid, 8,8'-[[1,1'-biphenyl]-4,4'-diylbis(azo)]bis[7-hydroxy-, tetrasodium salt-->SOLVENT RED 30-->Acid Red 374-->Acid Red 18-->Acid Green 50-->DIRECT RED 37-->Chromium, 8-[(5-chloro-2-hydroxyphenyl)azo]-7-hydroxy-1,3-naphthalenedisulfonic acid complex-->Acid Red 73-->DIRECT FAST RED 3B-->CRYSTAL PONCEAU 6R-->1,3-Naphthalenedisulfonic acid, 8-[[2,2'-dimethyl-4'-[[2-oxo-1-[(phenylamino)carbonyl]propyl]azo][1,1'-biphenyl]-4-yl]azo]-7-hydroxy-, disodium salt-->Acid Orange 10 |
| Hazard Information | Back Directory | [Chemical Properties]
2-Hydroxynaphthalene-6,8-disulfonic acid [118-32-1]. (7-hydroxynaphthalene-1,3- disulfonic acid), G acid, C10H8O7S2, Mr 304.3: most salts of 55 are more readily soluble in water than those of R acid, with the notable exception of the potassium salt. Sulfonation with 20 % oleum at 100℃ yields 2-hydroxynaphthalene3,6,8-trisulfonic acid. Diazo coupling takes place in the 1-position, although the reaction is sluggish, as in the case of 2-hydroxynaphthalene8-sulfonic acid. | [Uses]
The G acid is aminated (Bucherer reaction) to give 2-aminonaphthalene-6,8- disulfonic acid and subjected to caustic fusion at 200℃ to yield 2,8-dihydroxynaphthalene-6-sulfonic acid (a precursor of g acid). It is also used as a coupling component for a wide range of azo colorants, e.g., C.I. Acid Orange 10, C.I. Acid Red 187, and C.I. Food Red 7. | [Production Methods]
2-Naphthol is added to 98 % sulfuric acid at 40℃. Then, 20 % oleum is added over 6 h and the temperature is allowed to rise to 60℃. The reaction is completed by heating for a further 16 h at 60℃ followed by 15 h at 80℃. After the reaction mixture has been poured into water, potassium chloride is added to the hot solution and the batch is cooled slowly to 35℃ before filtering off the crystalline dipotassium salt of G acid and carefully washing out any residual R salt; the yield is 60 %. In addition, R salt can be recovered from the filtrate in 12 % yield after conversion to its sodium salt. |
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