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Structural formula
Structure of 2-naphthol
Surname 2-naphthol
other names
  • β-naphthol
  • 2-hydroxynaphthalene
  • Naphth-2-ol
Molecular formula C 10 H 8 O
Brief description

white crystalline powder with a phenolic odor

External identifiers / databases
CAS number 135-19-3
EC number 205-182-7
ECHA InfoCard 100.004.712
PubChem 8663
Wikidata Q949232
Molar mass 144.17 g mol −1
Physical state



1.22 g cm −3

Melting point

123 ° C

boiling point

285 ° C

pK s value

9.57 (25 ° C)


sparingly soluble in water: 1 g l −1 (20 ° C)

safety instructions
GHS hazard labeling from  Regulation (EC) No. 1272/2008 (CLP) , expanded if necessary
07 - Warning 09 - Dangerous for the environment


H and P phrases H: 302 + 332-400
P: 273
Toxicological data

1960 mg kg −1 ( LD 50ratoral )

As far as possible and customary, SI units are used. Unless otherwise noted, the data given apply to standard conditions .

2-naphthol (also β-naphthol ) is an organic chemical compound. The structure consists of a naphthalene structure with an attached hydroxyl group  (-OH). It can therefore also be called 2-hydroxynaphthalene. There is another isomer , 1-naphthol (α-naphthol, 1-hydroxynaphthalene).



The compound can be obtained by alkaline hydrolysis of sodium naphthalene-2-sulfonate, by oxidation of naphthalene or from 2-bromonaphthalene and tert-butyl hydroperoxide .


2-Naphthol is a crystalline solid that melts at 123 ° C. According to Antoine, the vapor pressure function of the melt results from log 10 (P) = A− (B / (T + C)) (P in kPa, T in K) with A = 3.058, B = 467.4 and C = −257 , 6 in the temperature range from 130 ° C to 160 ° C.


2-Napththol can be converted, for example, with methanol or with ethanol to form the methyl or ethyl ether, 2-methoxynaphthalene or 2-ethoxynaphthalene . These ethers are used as artificial fragrances .

Some Sudan dyes are derived from 2-naphthol, such as Sudan I , Sudan II , Sudan III , Sudan IV , Sudan Red B and Sudan red G .

Individual evidence

  1. a b c d e f g h Entry on 2-naphthol in the GESTIS substance database of the IFA , accessed on January 10, 2017(JavaScript required) .
  2. Zvi Rappoport (Ed.): CRC Handbook of Tables for Organic Compound Identification . 3 rd Edition, CRC Press / Taylor and Francis, Boca Raton, FL, 1967, ISBN 0-8493-0303-6 , Acid Dissociation Constants of Phenols in Aqueous Solution, S. 434th
  3. Entry on 2-naphthol in the Classification and Labeling Inventory of the European Chemicals Agency (ECHA), accessed on August 1, 2016. Manufacturers or distributors can expand the harmonized classification and labeling .
  4. Toxicological assessment of 2-naphthol (PDF) at the professional association raw materials and chemical industry (BG RCI), accessed on August 20, 2012.
  5. ^ Gerhard Wendt, B. Vithal Shetty, William F. Bruce: Mercurial Diuretics. I. Addition of Mercuric Chloride and Secondary Amines to Allylamides. In: Journal of the American Chemical Society. 81, 1959, p. 4233, doi : 10.1021 / ja01525a029 .
  6. F. Barontini, V. Cozzani: thermogravimetric as a screening tool for the estimation of the vapor pressure of pure compounds. In: J. Therm. Anal. Calorim. 89, 2007, pp. 309-314.