3-hydroxynaphthalene-2,7-disulphonic acid

Name	3-hydroxynaphthalene-2,7-disulphonic acid
Synonyms	Aids018328 Aids-018328 2-Naphtholdisodiumsulfonate 2-Naphthol-3,6-disulfonic acid 2-Naphthol-3,6-Disulfonic Acid 2-Hydroxynaphthalene-3,6-disulfonicacid 3-hydroxynaphthalene-2,7-disulfonic acid 3-Hydroxy-2,7-naphthalenedisulfonic acid 2,7-Naphthalenedisulfonicacid, 3-hydroxy- 3-hydroxynaphthalene-2,7-disulphonic acid
CAS	148-75-4
EINECS	205-724-2
InChI	InChI=1/C10H8O7S2/c11-9-4-6-1-2-8(18(12,13)14)3-7(6)5-10(9)19(15,16)17/h1-5,11H,(H,12,13,14)(H,15,16,17)

Molecular Formula	C10H8O7S2
Molar Mass	304.3
Density	1.7421 (rough estimate)
Boling Point	415.13°C (rough estimate)
pKa	-0.20±0.40(Predicted)
Storage Condition	Room Temprature
Refractive Index	1.6000 (estimate)
Physical and Chemical Properties	White needle-like crystals, soluble in water and alcohol, almost insoluble in ether. Easily dissolved. The product of the sodium salt is called R salt ([135-51-3]), white needle-like crystals, easily soluble in water, slightly soluble in alcohol, insoluble in benzene. The aqueous solution has blue-green fluorescence. Deliquescence.

EPA chemical information	Information provided by: ofmpub.epa.gov (external link)
use	this product is an important intermediate of food pigment, azo dye and functional pigment. Also used as an intermediate for fluorescent indicators and many other reagents.
Production method	It is obtained by sulfonation of 2-naphthol. In addition to R acid, there is also G acid. Salting out the sulfonate with sodium chloride to obtain R salt. In industrial production, R salt is used as a by-product of G salt. After 2-naphthol is sulfonated with sulfuric acid to generate G acid and R acid, the sulfonate is diluted, and the G salt is precipitated out with potassium chloride (see 26250 for the process). The remaining waste acid liquid is salted out with sodium chloride to obtain R salt. Raw material consumption quota: 35000kg/t of waste acid of g salt and 14000kg/t of salt (above 90%).

Last Update：2024-04-10 22:29:15