2-Naphthol

2-Naphthol

Names
IUPAC name Naphthalen-2-ol
Other names 2-Hydroxynaphthalene; 2-Naphthalenol; beta-Naphthol; Naphth-2-ol
Identifiers
CAS Number	135-19-3 Y
3D model (Jmol)	Interactive image Interactive image
ChEBI	CHEBI:10432 Y
ChEMBL	ChEMBL14126 Y
ChemSpider	8341 Y
ECHA InfoCard	100.004.712
KEGG	C11713 Y
PubChem	8663
UNII	P2Z71CIK5H Y
InChI InChI=1S/C10H8O/c11-10-6-5-8-3-1-2-4-9(8)7-10/h1-7,11H Y Key: JWAZRIHNYRIHIV-UHFFFAOYSA-N Y InChI=1/C10H8O/c11-10-6-5-8-3-1-2-4-9(8)7-10/h1-7,11H Key: JWAZRIHNYRIHIV-UHFFFAOYAV
SMILES Oc2ccc1c(cccc1)c2 c1ccc2cc(ccc2c1)O
Properties
Chemical formula	C10H8O
Molar mass	144.17 g·mol−1
Appearance	Colorless crystalline solid
Density	1.280 g/cm3
Melting point	121 to 123 °C (250 to 253 °F; 394 to 396 K)
Boiling point	285 °C (545 °F; 558 K)
Solubility in water	0.74 g/L
Acidity (pKa)	9.51
Magnetic susceptibility (χ)	-98.25·10−6 cm3/mol
Hazards
Main hazards	Harmful when inhaled or swallowed; dangerous to environment, esp. aquatic organisms.
R-phrases	R20 R22 R50
S-phrases	S24 S25 S61
NFPA 704	1 2 0
Flash point	161 °C (322 °F)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Y  (what is YN ?)
Infobox references

2-Naphthol, or β-naphthol, is a fluorescent colorless (or occasionally yellow) crystalline solid with the formula C₁₀H₇OH. It is an isomer of 1-naphthol, differing by the location of the hydroxyl group on the naphthalene ring. The naphthols are naphthalene homologues of phenol, but more reactive. Both isomers are soluble in simple alcohols, ethers, and chloroform. 2-Naphthol is a widely used intermediate for the production of dyes and other compounds.

Traditionally, 2-naphthol is produced by a two-step process that begins with the sulfonation of naphthalene in sulfuric acid:

The sulfonic acid group is then cleaved in molten sodium hydroxide:

Neutralization of the product with acid gives 2-naphthol.

2-Naphthol can also be produced by a method analogous to the cumene process.

The Sudan dyes are popular dyes noted for being soluble in organic solvents. Several of the Sudan dyes are derived from 2-naphthol by coupling with diazonium salts. Sudan dyes I -IV and Sudan Red G consist of arylazo-substituted naphthols.

Sudan I

Sudan II

Sudan III

Sudan IV

They can be also used in the production of dyes and in organic synthesis. For example, 2-naphthol reacts to form BINOL.