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2-Naphthol

PubChem CID
8663
Structure
2-Naphthol_small.png
2-Naphthol_3D_Structure.png
2-Naphthol__Crystal_Structure.png
Molecular Formula
Synonyms
  • 2-NAPHTHOL
  • naphthalen-2-ol
  • 135-19-3
  • beta-naphthol
  • 2-Naphthalenol
Molecular Weight
144.17 g/mol
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Dates
  • Create:
    2004-09-16
  • Modify:
    2025-01-18
Description
2-naphthol is a naphthol carrying a hydroxy group at position 2. It has a role as an antinematodal drug, a genotoxin, a human xenobiotic metabolite, a mouse metabolite, a human urinary metabolite and a radical scavenger.
2-Naphthol is a colorless crystalline solid and an isomer of 1-naphthol, differing by the location of the hydroxyl group on naphthalene. The naphthols are naphthalene homologues of phenol, with the hydroxyl group being more reactive than in the phenols. 2-Naphthol has several different uses including dyes, pigments, fats, oils, insecticides, pharmaceuticals, perfumes, antiseptics, synthesis of fungicides, and antioxidants for rubber. Detection of 2-Naphthol in urine usually results from long-term persistent exposure to pesticides such as chlorpyrifos, but also due to exposure to naphthalene in older types of mothballs, fires that produce polyaromatic hydrocarbons (PAHs), and tobacco smoke.

1 Structures

1.1 2D Structure

Chemical Structure Depiction
2-Naphthol.png

1.2 3D Conformer

1.3 Crystal Structures

1 of 2
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CCDC Number
Crystal Structure Data
Crystal Structure Depiction
Crystal Structure Depiction

2 Names and Identifiers

2.1 Computed Descriptors

2.1.1 IUPAC Name

naphthalen-2-ol
Computed by Lexichem TK 2.7.0 (PubChem release 2021.10.14)

2.1.2 InChI

InChI=1S/C10H8O/c11-10-6-5-8-3-1-2-4-9(8)7-10/h1-7,11H
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.3 InChIKey

JWAZRIHNYRIHIV-UHFFFAOYSA-N
Computed by InChI 1.0.6 (PubChem release 2021.10.14)

2.1.4 SMILES

C1=CC=C2C=C(C=CC2=C1)O
Computed by OEChem 2.3.0 (PubChem release 2024.12.12)

2.2 Molecular Formula

C10H8O
Computed by PubChem 2.2 (PubChem release 2021.10.14)
C10H8O

2.3 Other Identifiers

2.3.1 CAS

135-19-3
1321-67-1

2.3.3 Deprecated CAS

860440-31-9

2.3.4 European Community (EC) Number

2.3.5 UNII

2.3.6 UN Number

2.3.7 ChEBI ID

2.3.8 ChEMBL ID

2.3.9 DSSTox Substance ID

2.3.10 HMDB ID

2.3.11 ICSC Number

2.3.12 KEGG ID

2.3.13 Metabolomics Workbench ID

2.3.14 NCI Thesaurus Code

2.3.15 Nikkaji Number

2.3.16 NSC Number

2.3.17 Wikidata

2.3.18 Wikipedia

2.4 Synonyms

2.4.1 MeSH Entry Terms

  • 2-hydroxynaphthalene
  • 2-naphthol
  • 2-naphthol, (1+)
  • 2-naphthol, 1,4,5,8-(14)C4-labeled
  • 2-naphthol, 7-(14)C-labeled
  • 2-naphthol, 8-(14)C-labeled
  • 2-naphthol, bismuth salt
  • 2-naphthol, magnesium salt
  • 2-naphthol, potassium salt
  • 2-naphthol, sodium salt
  • 2-naphthol, titanium(4+) salt
  • beta-naphthol

2.4.2 Depositor-Supplied Synonyms

3 Chemical and Physical Properties

3.1 Computed Properties

Property Name
Molecular Weight
Property Value
144.17 g/mol
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
XLogP3
Property Value
2.7
Reference
Computed by XLogP3 3.0 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Donor Count
Property Value
1
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Hydrogen Bond Acceptor Count
Property Value
1
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Rotatable Bond Count
Property Value
0
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Exact Mass
Property Value
144.057514874 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Monoisotopic Mass
Property Value
144.057514874 Da
Reference
Computed by PubChem 2.2 (PubChem release 2021.10.14)
Property Name
Topological Polar Surface Area
Property Value
20.2 Ų
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Heavy Atom Count
Property Value
11
Reference
Computed by PubChem
Property Name
Formal Charge
Property Value
0
Reference
Computed by PubChem
Property Name
Complexity
Property Value
133
Reference
Computed by Cactvs 3.4.8.18 (PubChem release 2021.10.14)
Property Name
Isotope Atom Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Atom Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Defined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Undefined Bond Stereocenter Count
Property Value
0
Reference
Computed by PubChem
Property Name
Covalently-Bonded Unit Count
Property Value
1
Reference
Computed by PubChem
Property Name
Compound Is Canonicalized
Property Value
Yes
Reference
Computed by PubChem (release 2021.10.14)

3.2 Experimental Properties

3.2.1 Physical Description

Dry Powder
White solid; Darkens upon aging and exposure to sunlight; [Hawley] Tan chips with a phenol-like odor; [MSDSonline]
Solid
WHITE-TO-YELLOWISH-WHITE CRYSTALS WITH CHARACTERISTIC ODOUR.

3.2.2 Color / Form

White, lustrious, bulky leaflets or white powder. Darkens with age
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874

3.2.3 Odor

Faint phenol-like odor
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874

3.2.4 Boiling Point

285 °C
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874
285.00 to 286.00 °C. @ 760.00 mm Hg
The Good Scents Company Information System

3.2.5 Melting Point

121.6 °C
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874
123 °C
122 °C

3.2.6 Flash Point

152.7 °C
153 °C
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 6th Edition Volume 1: A-K,Volume 2: L-Z. William Andrew, Waltham, MA 2012, p. 1904
153 °C (307 °F) (Closed cup)
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
307 °F (153 °C) (Closed cup)
National Fire Protection Association; Fire Protection Guide to Hazardous Materials. 14TH Edition, Quincy, MA 2010, p. 325-91

3.2.7 Solubility

In water, 7.55X10+2 mg/L at 25 °C
Yalkowsky, S.H., He, Yan, Jain, P. Handbook of Aqueous Solubility Data Second Edition. CRC Press, Boca Raton, FL 2010, p. 651
Soluble in alcohol, ether, chloroform, glycerol, oils, alkaline solutions
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874
Very soluble in ethanol, ethyl ether; soluble in benzene, chloroform; slightly soluble in ligroin
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-406
1 gram dissolves in 1000 mL water, 80 mL boiling water, 0.8 mL alcohol, 17 mL chloroform, 1.3 mL ether
O'Neil, M.J. (ed.). The Merck Index - An Encyclopedia of Chemicals, Drugs, and Biologicals. Cambridge, UK: Royal Society of Chemistry, 2013., p. 1189
755 mg/L @ 25 °C (exp)
The Good Scents Company Information System
Solubility in water, g/100ml at 25 °C: 0.074

3.2.8 Density

1.28 g/cu cm at 20 °C
Haynes, W.M. (ed.). CRC Handbook of Chemistry and Physics. 95th Edition. CRC Press LLC, Boca Raton: FL 2014-2015, p. 3-406
1.28 g/cm³

3.2.9 Vapor Density

Relative vapor density (air = 1): 5

3.2.10 Vapor Pressure

VP: 9.9 mm Hg at 144 °C
Boublik T et al; The Vapor Pressure of Pure Substances: Selected Values of the Temperature Dependence of the Vapor Pressures of some Pure Substances in the Normal and Low Pressure Region Vol 17. Amsterdam, Netherlands: Elsevier Sci Publ pg 768 (1984)
Vapor pressure = 2.9X10-3 mm Hg at 25 °C (extrapolated - Super cooled liquid)
Boublik T et al; The Vapor Pressure of Pure Substances: Selected Values of the Temperature Dependence of the Vapor Pressures of some Pure Substances in the Normal and Low Pressure Region Vol 17. Amsterdam, Netherlands: Elsevier Sci Publ pg 768 (1984)
3.2X10-4 mm Hg at 25 °C (solid) (Extrapolated using value obtained from Boublik T et al (1984))
Bidleman TF; Environ Sci Technol 22: 361-367 (1988)
Vapor pressure, Pa at 25 °C: 2

3.2.11 LogP

log Kow = 2.70
Hansch, C., Leo, A., D. Hoekman. Exploring QSAR - Hydrophobic, Electronic, and Steric Constants. Washington, DC: American Chemical Society., 1995., p. 66
2.70
HANSCH,C ET AL. (1995)
2.7

3.2.12 Henry's Law Constant

Henry's Law constant = 2.74X10-8 atm-cu m/mol at 25 °C
Abraham MH et al; J Pharm Sci 83: 1085-100 (1994)

3.2.13 Stability / Shelf Life

Stable under recommended storage conditions.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

3.2.14 Autoignition Temperature

550 °C

3.2.15 Odor Threshold

Odor Threshold Low: 0.01 [ppm]

Odor Threshold High: 11.4 [ppm]

[HSDB] Odor threshold from HSDB

0.01 ppm - 11.4 ppm
Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992., p. 1098

3.2.16 Dissociation Constants

pKa = 9.51 at 25 °C
Bhattacharyya D et al; Haz Waste Haz Mater 3: 405-29 (1986)

3.2.17 Collision Cross Section

123.43 Ų [M+H]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

129.8 Ų [M+Na]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

125.11 Ų [M+H-H2O]+ [CCS Type: TW; Method: calibrated with polyalanine and drug standards]

Ross et al. JASMS 2022; 33; 1061-1072. DOI:10.1021/jasms.2c00111

3.2.18 Kovats Retention Index

Standard non-polar
1560.1 , 1517 , 1531 , 1524 , 1471
Semi-standard non-polar
1514.5 , 1520.1 , 1520.5 , 1520.5 , 1523.8 , 1497 , 1514.5 , 1520.1 , 1520.5 , 1520.5 , 1523.8 , 1525 , 1536 , 1522 , 1525 , 260.22 , 259.7 , 260.22

3.2.19 Other Experimental Properties

Hydroxyl radical reaction rate constant= 1.70X10-10 cu cm/molec-sec at 25 °C
Bunce NJ et al; Environ Sci Technol 31: 2252-9 (1997)

3.3 SpringerMaterials Properties

3.4 Chemical Classes

Other Classes -> Naphthols

3.4.1 Endocrine Disruptors

Potential endocrine disrupting compound
S109 | PARCEDC | List of 7074 potential endocrine disrupting compounds (EDCs) by PARC T4.2 | DOI:10.5281/zenodo.10944198

4 Spectral Information

4.1 1D NMR Spectra

1D NMR Spectra

4.1.1 1H NMR Spectra

1 of 3
View All
Spectra ID
Instrument Type
JEOL
Frequency
400 MHz
Solvent
CDCl3
Shifts [ppm]:Intensity
7.30:249.00, 7.74:66.00, 7.34:357.00, 7.42:358.00, 7.77:374.00, 7.30:224.00, 7.65:470.00, 7.40:264.00, 7.44:237.00, 7.10:637.00, 7.64:437.00, 7.34:348.00, 7.72:582.00, 7.77:391.00, 7.75:1000.00, 7.08:539.00, 7.10:383.00, 7.13:496.00, 7.67:362.00, 7.43:239.00, 7.75:903.00, 7.42:223.00, 7.32:530.00, 7.12:716.00, 7.42:468.00, 7.08:406.00, 7.67:391.00, 7.32:329.00, 7.40:296.00, 7.32:289.00
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2 of 3
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Instrument Name
BRUKER AC-300
Source of Sample
The Matheson Company, Inc., East Rutherford, New Jersey
Copyright
Copyright © 1991-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.1.2 13C NMR Spectra

1 of 3
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Spectra ID
Instrument Type
Varian
Frequency
25.16 MHz
Solvent
CDCl3
Shifts [ppm]:Intensity
128.98:426.00, 117.72:889.00, 153.22:593.00, 134.58:407.00, 127.77:846.00, 129.87:827.00, 126.54:1000.00, 126.39:963.00, 123.66:951.00, 109.57:815.00
Thumbnail
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2 of 3
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Source of Sample
J. T. Baker Chemical Company, Phillipsburg, New Jersey
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.2 Mass Spectrometry

4.2.1 GC-MS

1 of 8
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Spectra ID
Instrument Type
EI-B
Ionization Mode
positive
Top 5 Peaks

144.0 99.99

115.0 33.41

145.0 11.26

116.0 9.89

63.0 5.47

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Notes
instrument=HITACHI M-80A
2 of 8
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MoNA ID
MS Category
Experimental
MS Type
GC-MS
MS Level
MS1
Instrument
HITACHI M-80A
Instrument Type
EI-B
Ionization Mode
positive
Top 5 Peaks

144 99.99

115 33.41

145 11.26

116 9.89

63 5.47

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License
CC BY-NC-SA

4.2.2 MS-MS

1 of 7
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Spectra ID
Instrument Type
Orbitrap
Ionization Mode
positive
Top 5 Peaks

145.0648 97.69

117.0698 2.31

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Notes
adduct_type [M+H]+ original_collision_energy 8 nominal CannabisDB spectra from NIST14 2020 June Thermo Finnigan Elite Orbitrap
2 of 7
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Spectra ID
Instrument Type
Orbitrap
Ionization Mode
positive
Top 5 Peaks

145.0648 89.53

117.0699 8.68

127.0542 1.79

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Notes
adduct_type [M+H]+ original_collision_energy 11 nominal CannabisDB spectra from NIST14 2020 June Thermo Finnigan Elite Orbitrap

4.2.3 LC-MS

1 of 9
View All
Authors
Elapavalore, A.; Kondić, T.; Singh, R.; Schymanski, E.
Instrument
Q Exactive Orbitrap (Thermo Scientific)
Instrument Type
LC-ESI-QFT
MS Level
MS2
Ionization Mode
POSITIVE
Ionization
ESI
Collision Energy
15
Fragmentation Mode
HCD
Column Name
Acquity BEH C18 1.7um, 2.1x150mm (Waters)
Retention Time
15.689 min
Precursor m/z
145.0648
Precursor Adduct
[M+H]+
Top 5 Peaks

145.0646 999

117.0698 204

103.0542 19

127.0541 9

115.0541 9

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License
CC BY
Reference
Elapavalore, A.; Kondić, T.; et al., Adding Open Spectral Data to MassBank and PubChem Using Open Source Tools to Support Non-Targeted Exposomics of Mixtures (submitted).
2 of 9
View All
Authors
Elapavalore, A.; Kondić, T.; Singh, R.; Schymanski, E.
Instrument
Q Exactive Orbitrap (Thermo Scientific)
Instrument Type
LC-ESI-QFT
MS Level
MS2
Ionization Mode
POSITIVE
Ionization
ESI
Collision Energy
30
Fragmentation Mode
HCD
Column Name
Acquity BEH C18 1.7um, 2.1x150mm (Waters)
Retention Time
15.689 min
Precursor m/z
145.0648
Precursor Adduct
[M+H]+
Top 5 Peaks

145.0646 999

117.0698 205

103.0542 18

127.0541 10

115.0541 8

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License
CC BY
Reference
Elapavalore, A.; Kondić, T.; et al., Adding Open Spectral Data to MassBank and PubChem Using Open Source Tools to Support Non-Targeted Exposomics of Mixtures (submitted).

4.2.4 Other MS

1 of 3
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Other MS
MASS: 4011 (NIST/EPA/MSDC Mass Spectral Database, 1990 version)
2 of 3
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Authors
ACESx, Jonathan W. Martin Group
Instrument
QExactive Orbitrap HF-X (Thermo Scientific)
Instrument Type
LC-APCI-QFT
MS Level
MS2
Ionization Mode
NEGATIVE
Ionization
APCI
Collision Energy
Ramp 20%-70% (nominal)
Fragmentation Mode
HCD
Column Name
Waters; Acquity UPLC BEH C18, 2.1 x 100 mm, 1.7 um, Waters
Retention Time
13.6994
Precursor m/z
143.0503
Top 5 Peaks

143.05049 999

115.05554 163

144.05396 116

145.07738 47

143.10722 28

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License
CC BY

4.3 UV Spectra

UV: 2551 (Sadtler Research Laboratories spectral collection)
Lide, D.R., G.W.A. Milne (eds.). Handbook of Data on Organic Compounds. Volume I. 3rd ed. CRC Press, Inc. Boca Raton ,FL. 1994., p. V4: 3585

4.4 IR Spectra

IR Spectra
IR: 2218 (Coblentz Society spectral collection)

4.4.1 FTIR Spectra

1 of 2
Technique
FILM (CAST FROM CHLOROFORM)
Source of Sample
J. T. Baker Chemical Company
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Instrument Name
Bruker IFS 85
Technique
KBr-Pellet
Source of Sample
E. Merck AG, Darmstadt
Copyright
Copyright © 1989, 1990-2024 Wiley-VCH Verlag GmbH & Co. KGaA. All Rights Reserved.
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4.4.2 ATR-IR Spectra

Source of Sample
Aldrich
Catalog Number
185507
Copyright
Copyright © 2018-2024 Sigma-Aldrich Co. LLC. - Database Compilation Copyright © 2018-2024 John Wiley & Sons, Inc. All Rights Reserved.
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4.4.3 Vapor Phase IR Spectra

1 of 2
Instrument Name
DIGILAB FTS-14
Technique
Vapor Phase
Copyright
Copyright © 1980, 1981-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Source of Spectrum
Sigma-Aldrich Co. LLC.
Source of Sample
Sigma-Aldrich Co. LLC.
Catalog Number
185507
Copyright
Copyright © 2021-2024 Sigma-Aldrich Co. LLC. - Database Compilation Copyright © 2021 John Wiley & Sons, Inc. All Rights Reserved.
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4.5 Raman Spectra

1 of 2
Technique
FT-Raman
Source of Spectrum
Forensic Spectral Research
Source of Sample
Sigma-Aldrich Company LLC
Catalog Number
<a href=https://www.sigmaaldrich.com/US/en/product/aldrich/185507>185507</a>
Lot Number
STBF1199V
Copyright
Copyright © 2015-2024 John Wiley & Sons, Inc. All Rights Reserved.
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2 of 2
Catalog Number
185507
Copyright
Copyright © 2017-2024 Sigma-Aldrich Co. LLC. - Database Compilation Copyright © 2017-2024 John Wiley & Sons, Inc. All Rights Reserved.
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6 Chemical Vendors

7 Drug and Medication Information

7.1 Therapeutic Uses

2-Naphthol ... has had medical uses as a counterirritant in alopecia, also as an anthelmintic, and as an antiseptic in treatment of scabies.
Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 655

7.2 Drug Warnings

2-Naphthol-containing pastes should be applied only for short periods of time and to a limited area not exceeding 150 square cm.
Marzulli, F.N., H.I. Maibach. Dermatotoxicology 4th ed. New York, NY: Hemisphere Publishing Corp., 1991., p. 864

7.3 Biomarker Information

8 Food Additives and Ingredients

8.1 Associated Foods

9 Pharmacology and Biochemistry

9.1 Absorption, Distribution and Excretion

Between 5 and 10% of a cutaneous dose /of 2-naphthol/ has been recovered from the urine ... .
Marzulli, F.N., H.I. Maibach. Dermatotoxicology 4th ed. New York, NY: Hemisphere Publishing Corp., 1991., p. 864

9.2 Metabolism / Metabolites

Several pathways of drug metabolizing enzyme activity were measured in hepatic fractions of cattle, sheep, goats, chickens, turkeys, ducks, rabbits and rats. The pathways examined included the O-demethylation of p-nitrophenol, microsomal ester hydrolysis of procaine and glucuronidation of p-nitrophenol, and the cytosolic acetylation of sulfamethazine and sulfation of 2-naphthol. For most enzymatic pathways measured, goats were more similar to sheep (wether) than to cattle (steers). The exception was UDP-glucuronyltransferase activity, which was significantly higher for the goat than for any other species studied. Within the avian subset, the chicken and turkey were usually the most similar species. The activities of arylsulfotransferase isozymes III and IV were particularly low for the duck compared to the chicken and turkey. N-acetyltransferase activity was very high for rabbits and very low for sheep and goats.
Short CR et al; Comp Biochem Physiol C 91 (2): 419-24 (1988)
Several pathways of drug metabolizing enzymic activity were measured in hepatic fractions of the channel catfish and rat using model substrates. The pathways examined included the O-demethylation of p-nitroanisole, microsomal ester hydrolysis of procaine and glucuronidation of p-nitrophenol and the cytosolic acetylation of sulfamethazine and sulfation of 2-naphthol. Catfish liver preparations were incubated at both 25 °C and 37 °C. The oxidative metabolism of p-nitrophenol was only 1/8 of that of the rat at 37 °C and 1/12 that of the rat at 25 °C. Procaine ester hydrolysis was negligible in catfish microsomal preparations. At 37 °C, p-nitrophenol glucuronidation was equivalent in catfish and rat microsomes. Catfish cytosolic preparations exhibited N-acetyltransferase and arylsulfotransferase nearly comparable to those of the rat. Rates of glucuronidation and sulfation were higher at 37 °C than at 25 °C in hepatic fractions of the catfish.
Short CR et al; Comp Biochem Physiol C 89 (2): 153-7 (1988)
To characterize the substrate specificities of various isozymes of carboxylesterases, a series of carbonates, thiocarbonates, carbamates, and carboxylic acid esters containing alpha- or beta-naphthol or p-nitrophenol as leaving groups were tested as substrates of human, rat and mouse liver microsomal esterases; hydrolases A and B from rat liver microsomes were also tested. The carbonates, thiocarbonates, and carboxylic esters of alpha-naphthol were cleaved more rapidly than the corresponding beta-naphthol isomers by the mammalian liver esterases. The majority of the substrates was consistently hydrolyzed at higher rates by hydrolase B compared with hydrolase A. Compared with the corresponding carboxylates, the carbonate moiety of alpha- and beta-naphthol and p-nitrophenol lowered the specific activities of the enzymes by about 5 fold but improved stability under basic conditions. Human and mouse liver microsomal esterase activities were 5 orders of magnitude lower than the esterase activities of hydrolase B. The functional group and lipophilicity of the substrate structure influenced the activity of mammalian esterases.
Huang TL et al; Pharm Res 10: 639-48 (1993)
The inhibition of hydroxysteroid-sulfotransferase (ST) activity in the rat liver by alkylamines was investigated. Liver homogenates were prepared from Wistar rats, and cytosolic fractions were obtained. ST activities towards dehydroepiandrosterone (DHEA), androsterone (AS), and 2-naphthol (2NA) were assayed. Cytosolic fractions were fractionated by column chromatography. Triethylamine, which was used as an elution solvent for column chromatography to purify chemically synthesized 3-phosphoadenosine-5-phosphosulfate (PAPS) inhibited androgen sulfation with AS and DHEA, but did not affect ST activities with cortisol and 2-NA. The sulfate donor ability of various PAPS preparations were compared. Fourteen primary, secondary, and tertiary amines were examined for inhibitory actions on ST activities towards DHEA, cortisol, and 2-NA. A secondary amine, di-n-butylamine, and three tertiary amines, triethylamine, tri-n-propylamine and tri-n-butylamine, inhibited DHEA ST activity by 40 to 60%, irrespective of sex. However, 2-NA and cortisol ST activities were not affected to any significant extent. Lineweaver Burk plots with partially purified hydroxysteroid ST indicated that the inhibition by triethylamine fitted a noncompetitive inhibition. The /results/ conclude that glucocorticoid ST appears to be distinct from the hydroxysteroid ST, and that this has implications for the inhibition of human liver ST activities by synthetic steroids and tertiary amines given as drugs.
Matsui M et al; Biochem Pharmacology 46 (3): 465-70 (1993)
For more Metabolism/Metabolites (Complete) data for 2-NAPHTHOL (8 total), please visit the HSDB record page.
2-Naphthol is a known human metabolite of naphthalene.
S73 | METXBIODB | Metabolite Reaction Database from BioTransformer | DOI:10.5281/zenodo.4056560

9.3 Human Metabolite Information

9.3.1 Cellular Locations

Membrane

9.4 Biochemical Reactions

9.5 Transformations

10 Use and Manufacturing

10.1 Uses

EPA CPDat Chemical and Product Categories
The Chemical and Products Database, a resource for exposure-relevant data on chemicals in consumer products, Scientific Data, volume 5, Article number: 180125 (2018), DOI:10.1038/sdata.2018.125
Sources/Uses
Used to make dyes, pigments, fungicides, insecticides, pharmaceuticals, and perfumes; Also used as antioxidants for rubber, fats, and oils; as an antiseptic; for lubrication of steam turbines, electric motors, hydraulic equipment, and instruments; and formerly as an anthelmintic; [HSDB] Also used as an additive in electroplating, developer in dyeing and printing of fabrics, in tanneries, and in the paints-lacquers-varnishes industry; [IUCLID]
Industrial Processes with risk of exposure
MEDICATION
For 2-naphthol (USEPA/OPP Pesticide Code: 010301) there are 0 labels match. /SRP: Not registered for current use in the U.S., but approved pesticide uses may change periodically and so federal, state and local authorities must be consulted for currently approved uses./
National Pesticide Information Retrieval System's Database on 2-Naphthol (135-19-3). Available from, as of September 8, 2014: https://npirspublic.ceris.purdue.edu/ppis/
The principal uses for 2-naphthalenol are in the dyes and pigments industries, eg, as a coupling component for azo dyes, and to make important intermediates, such as 3-hydroxy-2-naphthalenecarboxylic acid (BON) and its anilide (naphthol AS), 2-naphtholsulfonic acids, aminonaphtholsulfonic acids, and 1-nitroso-2-naphthol.
Talukder M, Kates CR; Naphthalene Derivatives. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2014). John Wiley & Sons, Inc. Online Posting Date: December 4, 2000
Antioxidants for ... fats, oils; insecticides; synthesis of fungicides; ... antiseptic.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874
For more Uses (Complete) data for 2-NAPHTHOL (8 total), please visit the HSDB record page.
This is a man-made compound that is used as a pesticide.

10.1.1 Industry Uses

  • Dye
  • Pigments
  • Intermediates

10.1.2 Consumer Uses

Dye

10.2 Methods of Manufacturing

2-Naphthol is produced by caustic fusion of naphthalene-2-sulfonic acid. Typically, the sodium salt of the sulfonic acid is added gradually to 50% sodium hydroxide liquor at 300 °C; the melt is then heated further at 320 °C in a gas-fired iron vessel with vigorous agitation. After completion of the reaction, the melt is run into excess water, possibly including filtrate from the previous batch at a proven tolerable level, and the naphtholate solution is neutralized to pH 8 with dilute sulfuric acid. If the temperature is maintained at >100 °C during neutralization, the crude product comes out of solution as an oil, which is separated, washed with hot water, and distilled under vacuum to give pure 2-naphthol. The molten material is processed through a flaker to give the final product for packaging. The fusion yield is about 80% of the theoretical value, resulting in an overall yield of 70% based on naphthalene.
Booth G; Naphthalene Derivatives. Ullmann's Encyclopedia of Industrial Chemistry 7th ed. (1999-2014). NY, NY: John Wiley & Sons. Online Posting Date: June 15, 2000
... Alkylation and isomerization are carried out up to 240 °C with a phosphoric acid catalyst. Final catalytic oxidation at 90 - 110 °C gives the hydroperoxide, which is cleaved with dilute sulfuric acid to give 2-naphthol in high overall yield in spite of modest oxidation conversion.
Booth G; Naphthalene Derivatives. Ullmann's Encyclopedia of Industrial Chemistry 7th ed. (1999-2014). NY, NY: John Wiley & Sons. Online Posting Date: June 15, 2000
By fusing sodium beta-naphthalene sulfonate with caustic soda. Product is distilled in vacuo and then sublimed.
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874

10.3 Formulations / Preparations

Grade: Technical, sublimed, resublimed
Lewis, R.J. Sr.; Hawley's Condensed Chemical Dictionary 15th Edition. John Wiley & Sons, Inc. New York, NY 2007., p. 874

10.4 U.S. Production

Aggregated Product Volume

2019: 1,000,000 lb - <20,000,000 lb

2018: 100,000 - <500,000 lb

2017: 100,000 - <500,000 lb

2016: 100,000 - <500,000 lb

2-Naphthalenol is listed as a High Production Volume (HPV) chemical (65FR81686). Chemicals listed as HPV were produced in or imported into the U.S. in >1 million pounds in 1990 and/or 1994. The HPV list is based on the 1990 Inventory Update Rule. (IUR) (40 CFR part 710 subpart B; 51FR21438).
EPA/Office of Pollution Prevention and Toxics; High Production Volume (HPV) Challenge Program. 2-Naphthalenol (135-19-3). Available from, as of August 28, 2014: https://www.epa.gov/hpv/pubs/general/opptsrch.htm
Production volume for non-confidential chemicals reported under the 2006 Inventory Update Rule. Chemical: 2-Naphthalenol. Aggregated National Production Volume: 1 to < 10 million pounds.
US EPA; Non-Confidential 2006 Inventory Update Reporting. National Chemical Information. 2-Naphthalenol (135-19-3). Available from, as of September 2, 2014: https://cfpub.epa.gov/iursearch/index.cfm
Non-confidential 2012 Chemical Data Reporting (CDR) information on the production and use of chemicals manufactured or imported into the United States. Chemical: 2-Naphthalenol. National Production Volume: 1,000,000 - 10,000,000 lb/yr.
USEPA/Pollution Prevention and Toxics; 2012 Chemical Data Reporting Database. 2-Naphthalenol (135-19-3). Available from, as of September 2, 2014: https://java.epa.gov/oppt_chemical_search/

10.5 General Manufacturing Information

Industry Processing Sectors
Synthetic Dye and Pigment Manufacturing
EPA TSCA Commercial Activity Status
2-Naphthalenol: ACTIVE

11 Identification

11.1 Clinical Laboratory Methods

Enzyme linked immunosorbent assay for the specific detection of the mercapturic acid metabolites of naphthalene.
Marco MP et al; Chem Res Toxicol 6 (3): 284-93 (1993)

12 Safety and Hazards

12.1 Hazards Identification

12.1.1 GHS Classification

1 of 7
View All
Pictogram(s)
Corrosive
Irritant
Environmental Hazard
Signal
Danger
GHS Hazard Statements

H302+H332 (56.3%): Harmful if swallowed or if inhaled [Warning Acute toxicity, oral; acute toxicity, inhalation]

H302 (> 99.9%): Harmful if swallowed [Warning Acute toxicity, oral]

H317 (60.1%): May cause an allergic skin reaction [Warning Sensitization, Skin]

H318 (17.2%): Causes serious eye damage [Danger Serious eye damage/eye irritation]

H332 (93.7%): Harmful if inhaled [Warning Acute toxicity, inhalation]

H400 (99.8%): Very toxic to aquatic life [Warning Hazardous to the aquatic environment, acute hazard]

Precautionary Statement Codes

P261, P264, P264+P265, P270, P271, P272, P273, P280, P301+P317, P302+P352, P304+P340, P305+P354+P338, P317, P321, P330, P333+P317, P362+P364, P391, and P501

(The corresponding statement to each P-code can be found at the GHS Classification page.)

ECHA C&L Notifications Summary

Aggregated GHS information provided per 1028 reports by companies from 14 notifications to the ECHA C&L Inventory. Each notification may be associated with multiple companies.

Information may vary between notifications depending on impurities, additives, and other factors. The percentage value in parenthesis indicates the notified classification ratio from companies that provide hazard codes. Only hazard codes with percentage values above 10% are shown.

12.1.2 Hazard Classes and Categories

Acute Tox. 4 (> 99.9%)

Skin Sens. 1 (60.1%)

Eye Dam. 1 (17.2%)

Acute Tox. 4 (93.7%)

Aquatic Acute 1 (99.8%)

Acute toxicity - category 4

Acute toxicity - category 4

Hazardous to the aquatic environment (acute) - category 1

12.1.3 NFPA Hazard Classification

NFPA 704 Diamond
0-1-0
NFPA Health Rating
0 - Materials that, under emergency conditions, would offer no hazard beyond that of ordinary combustible materials.
NFPA Fire Rating
1 - Materials that must be preheated before ignition can occur. Materials require considerable preheating, under all ambient temperature conditions, before ignition and combustion can occur.
NFPA Instability Rating
0 - Materials that in themselves are normally stable, even under fire conditions.

12.1.4 Fire Hazards

Combustible. Finely dispersed particles form explosive mixtures in air.

12.1.5 Hazards Summary

A severe eye irritant; May cause skin sensitization; The substance may have effects on the kidneys, blood and eyes, resulting in kidney impairment, anaemia and lens opacities. [ICSC] Emergency medical treatment: see Phenol. [HSDB] An irritant; May cause injury to eyes; May be absorbed through skin resulting in kidney injury; [MSDSonline]

12.1.6 Fire Potential

Flammability potential is slight.
Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992., p. 1098

12.1.7 Skin, Eye, and Respiratory Irritations

A skin and eye irritant.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 2602
Irritates skin and eyes.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 6th Edition Volume 1: A-K,Volume 2: L-Z. William Andrew, Waltham, MA 2012, p. 1905

12.2 Safety and Hazard Properties

12.2.1 Physical Dangers

Dust explosion possible if in powder or granular form, mixed with air.

12.3 First Aid Measures

Inhalation First Aid
Fresh air, rest.
Skin First Aid
Rinse and then wash skin with water and soap.
Eye First Aid
First rinse with plenty of water for several minutes (remove contact lenses if easily possible), then refer for medical attention.
Ingestion First Aid
Rinse mouth. Give one or two glasses of water to drink. Refer for medical attention .

12.4 Fire Fighting

Use water spray, powder, foam, carbon dioxide.

12.4.1 Fire Fighting Procedures

Suitable extinguishing media: Use water spray, alcohol-resistant foam, dry chemical or carbon dioxide.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Advice for firefighters: Wear self contained breathing apparatus for fire fighting if necessary.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.4.2 Firefighting Hazards

Combustible when exposed to heat or flame.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 2602

12.5 Accidental Release Measures

12.5.1 Spillage Disposal

Personal protection: particulate filter respirator adapted to the airborne concentration of the substance. Sweep spilled substance into covered containers. If appropriate, moisten first to prevent dusting. Do NOT let this chemical enter the environment.

12.5.2 Cleanup Methods

Accidental Release Measures. Personal precautions, protective equipment and emergency procedures: Use personal protective equipment. Avoid dust formation. Avoid breathing vapours, mist or gas. Ensure adequate ventilation. Evacuate personnel to safe areas. Avoid breathing dust. Environmental precautions: Prevent further leakage or spillage if safe to do so. Do not let product enter drains. Discharge into the environment must be avoided. Methods and materials for containment and cleaning up: Pick up and arrange disposal without creating dust. Sweep up and shovel. Keep in suitable, closed containers for disposal.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.5.3 Disposal Methods

SRP: The most favorable course of action is to use an alternative chemical product with less inherent propensity for occupational harm/injury/toxicity or environmental contamination. Recycle any unused portion of the material for its approved use or return it to the manufacturer or supplier. Ultimate disposal of the chemical must consider: the material's impact on air quality; potential migration in soil or water; effects on animal and plant life; and conformance with environmental and public health regulations.
Mix with flammable solvent and atomize into an incinerator.
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 6th Edition Volume 1: A-K,Volume 2: L-Z. William Andrew, Waltham, MA 2012, p. 1905
Waste treatment methods. Product: Offer surplus and non-recyclable solutions to a licensed disposal company. Contact a licensed professional waste disposal service to dispose of this material. Contaminated packaging: Dispose of as unused product.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.5.4 Preventive Measures

SRP: The scientific literature for the use of contact lenses by industrial workers is inconsistent. The benefits or detrimental effects of wearing contact lenses depend not only upon the substance, but also on factors including the form of the substance, characteristics and duration of the exposure, the uses of other eye protection equipment, and the hygiene of the lenses. However, there may be individual substances whose irritating or corrosive properties are such that the wearing of contact lenses would be harmful to the eye. In those specific cases, contact lenses should not be worn. In any event, the usual eye protection equipment should be worn even when contact lenses are in place.
Precautions for safe handling: Avoid contact with skin and eyes. Avoid formation of dust and aerosols. Provide appropriate exhaust ventilation at places where dust is formed.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Appropriate engineering controls: Handle in accordance with good industrial hygiene and safety practice. Wash hands before breaks and at the end of workday.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Gloves must be inspected prior to use. Use proper glove removal technique (without touching glove's outer surface) to avoid skin contact with this product. Dispose of contaminated gloves after use in accordance with applicable laws and good laboratory practices. Wash and dry hands.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.6 Handling and Storage

12.6.1 Safe Storage

Store in an area without drain or sewer access.

12.6.2 Storage Conditions

Conditions for safe storage, including any incompatibilities: Keep container tightly closed in a dry and well-ventilated place. Light sensitive.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.7 Exposure Control and Personal Protection

12.7.1 Inhalation Risk

A harmful concentration of airborne particles can be reached quickly when dispersed.

12.7.2 Effects of Short Term Exposure

The substance is severely irritating to the eyes.

12.7.3 Effects of Long Term Exposure

Repeated or prolonged contact may cause skin sensitization. The substance may have effects on the kidneys, blood and eyes. This may result in kidney impairment, anaemia and lens opacities.

12.7.4 Personal Protective Equipment (PPE)

Eye/face protection: Safety glasses with side-shields conforming to EN166 Use equipment for eye protection tested and approved under appropriate government standards such as NIOSH (US) or EN 166(EU).
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Skin protection: Handle with gloves.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Body Protection: Complete suit protecting against chemicals, The type of protective equipment must be selected according to the concentration and amount of the dangerous substance at the specific workplace.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html
Respiratory protection: For nuisance exposures use type P95 (US) or type P1 (EU EN 143) particle respirator.For higher level protection use type OV/AG/P99 (US) or type ABEK-P2 (EU EN 143) respirator cartridges. Use respirators and components tested and approved under appropriate government standards such as NIOSH (US) or CEN (EU).
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.7.5 Preventions

Fire Prevention
NO open flames. Closed system, dust explosion-proof electrical equipment and lighting. Prevent deposition of dust.
Exposure Prevention
PREVENT DISPERSION OF DUST!
Inhalation Prevention
Use local exhaust or breathing protection.
Skin Prevention
Protective gloves. Protective clothing.
Eye Prevention
Wear safety goggles or eye protection in combination with breathing protection if powder.
Ingestion Prevention
Do not eat, drink, or smoke during work.

12.8 Stability and Reactivity

12.8.1 Hazardous Reactivities and Incompatibilities

Incompatible with antipyrine, camphor, phenol, ferric salts, menthol, potassium permanganate and other oxidizing materials, urethane.
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 2602
Pohanish, R.P. (ed). Sittig's Handbook of Toxic and Hazardous Chemical Carcinogens 6th Edition Volume 1: A-K,Volume 2: L-Z. William Andrew, Waltham, MA 2012, p. 1904
Incompatible materials: Strong oxidizing agents, strong bases.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

12.9 Transport Information

12.9.1 EC Classification

Symbol: Xn, N; R: 20/22-50; S: (2)-24/25-61

12.9.2 UN Classification

UN Hazard Class: 9; UN Pack Group: III

12.10 Regulatory Information

The Australian Inventory of Industrial Chemicals
Chemical: 2-Naphthalenol
REACH Registered Substance
New Zealand EPA Inventory of Chemical Status
2-Naphthol: Does not have an individual approval but may be used under an appropriate group standard

12.10.1 Atmospheric Standards

This action promulgates standards of performance for equipment leaks of Volatile Organic Compounds (VOC) in the Synthetic Organic Chemical Manufacturing Industry (SOCMI). The intended effect of these standards is to require all newly constructed, modified, and reconstructed SOCMI process units to use the best demonstrated system of continuous emission reduction for equipment leaks of VOC, considering costs, non air quality health and environmental impact and energy requirements. 2-naphthol is produced, as an intermediate or a final product, by process units covered under this subpart.
40 CFR 60.489 (USEPA); U.S. National Archives and Records Administration's Electronic Code of Federal Regulations. Available from, as of August 28, 2014: https://www.ecfr.gov

12.11 Other Safety Information

Chemical Assessment
IMAP assessments - 2-Naphthalenol: Human health tier I assessment

12.11.1 Toxic Combustion Products

Special hazards arising from the substance or mixture: Carbon oxides.
Sigma-Aldrich; Material Safety Data Sheet for 2-Naphthol. Product Number: 185507, Version 5.2 (Revision Date 06/28/2014). Available from, as of October 10, 2014: https://www.sigmaaldrich.com/safety-center.html

13 Toxicity

13.1 Toxicological Information

13.1.1 Toxicity Summary

IDENTIFICATION AND USE: 2- Naphthol is a white, bulky leaflets or white powder with faint phenol-like odor. The principal uses for 2-naphthol are in the dyes and pigments industries, eg, as a coupling component for azo dyes, and to make important intermediates, such as 3-hydroxy-2-naphthalenecarboxylic acid (BON) and its anilide (naphthol AS), 2-naphtholsulfonic acids, aminonaphtholsulfonic acids, and 1-nitroso-2-naphthol. The major pharmaceutical products based on 2-naphthol are the antifungal tolnaftate, produced by reaction with thiophosgene and N-methyl-m-toluidine; the semisynthetic penicillin nafcillin, produced via 2-ethoxynaphthalene; and the anti-inflammatory naproxen, produced via 2-methoxynaphthalene. It is also was used as a counterirritant in alopecia, also as an anthelmintic, and as an antiseptic in treatment of scabies. HUMAN EXPOSURE AND TOXICITY: The extensive application of 2-naphthol ointments has been responsible for systemic side effects, including vomiting and death. Ingestion can produce renal damage, vomiting, diarrhea, abdominal pain, syncope, convulsions, and hemolytic anemia. Twenty patients who were treated for scabies by rubbing 50 g of a salve containing 7.5% 2-naphthol over the whole body morning and evening for 2 days were reported to have developed hyperemia of the fundus and many had very small white and pigmented spots in the retina. Vitreous opacities were noticed in two cases. Only in one case was abnormality of the lens observed, and this was only a dot in the posterior cortex. Visual acuity was reported to be impaired in two cases, but neither of these had normal eyes before the treatment. ANIMAL STUDIES: Experimentally in rabbits the most consistent ocular change induced by admin 2-naphthol either by stomach or by application to the skin was a development in the retina of small white shiny flecks which soon became pigmented. These became more numerous and increased in size as daily admin of the chemical continued. The retinal vessels and the iris commonly became hyperemic. The aqueous was sometimes slightly turbid, and the vitreous commonly became turbid early, but then cleared despite continuing admin of naphthol. The cornea and conjunctiva were never involved. The other study reported that in the retinas of poisoned adult rabbits spotty degeneration of the rods and cones and irregular variation in the amt of pigment in the pigment epithelium were observed. Vacuoles were present in the nuclear and nerve fiber layer and the ciliary epithelium. When 2-naphthol was administered to pregnant rabbits, the offspring had congenital cataracts, degeneration of the neuroepithelium, and hypertrophy of the retinal pigment cells. An in vivo study was conducted of the biochemical pathways modulating the cataractogenicity of naphthalene. Male mice were treated with naphthalene or its metabolites and with various chemical probes that modulate critical biochemical pathways relevant to naphthalene bioactivation and detoxification. No cataractogenic or lethal effects from 2-naphthol were noted at dose levels of 56 or 100 mg/kg; however doses of 177 and 562 mg/kg killed all the animals within 1.5 hr. ECOTOXICITY STUDIES: As test systems, fish embryos and larvae were the most sensitive, juvenile fathead minnows and arthropods had intermediate sensitivity and algae and snails were the most resistant to the test compounds.

13.1.2 Carcinogen Classification

Carcinogen Classification
No indication of carcinogenicity to humans (not listed by IARC).

13.1.3 Exposure Routes

The substance can be absorbed into the body by inhalation of its aerosol, through the skin and by ingestion.

13.1.4 Symptoms

Inhalation Exposure
Cough. Sore throat.
Eye Exposure
Redness. Pain. Blurred vision.
Ingestion Exposure
Abdominal pain. Nausea. Vomiting. Diarrhoea.

13.1.5 Adverse Effects

Skin Sensitizer - An agent that can induce an allergic reaction in the skin.

13.1.6 Acute Effects

13.1.7 Toxicity Data

LC50 (rat) = 2,200 mg/m3/4h

13.1.8 Antidote and Emergency Treatment

Immediate first aid: Ensure that adequate decontamination has been carried out. If patient is not breathing, start artificial respiration, preferably with a demand-valve resuscitator, bag-valve-mask device, or pocket mask, as trained. Perform CPR as necessary. Immediately flush contaminated eyes with gently flowing water. Do not induce vomiting. If vomiting occurs, lean patient forward or place on left side (head-down position, if possible) to maintain an open airway and prevent aspiration. Keep patient quiet and maintain normal body temperature. Obtain medical attention. /Phenols and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 277
Basic treatment: Establish a patent airway (oropharyngeal or nasopharyngeal airway, if needed). Suction if necessary. Watch for signs of respiratory insufficiency and assist ventilations if necessary. Administer oxygen by nonrebreather mask at 10 to 15 L/min. Monitor for pulmonary edema and treat if necessary ... . Monitor for shock and treat if necessary ... . Anticipate seizures and treat if necessary ... . For eye contamination, flush eyes immediately with water. Irrigate each eye continuously with 0.9% saline (NS) during transport ... . Administer activated charcoal ... . Dilution may be contraindicated because if may increase absorption. Do not use emetics. Cover skin burns with dry, sterile dressings after decontamination ... . Maintain body temperature. /Phenols and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 277
Advanced treatment: Consider orotracheal or nasotracheal intubation for airway control in the patient who is unconscious, has severe pulmonary edema, or is in severe respiratory distress. Positive pressure ventilation techniques with a bag valve mask device may be beneficial. Consider drug therapy for pulmonary edema ... . Monitor cardiac rhythm and treat arrhythmias if necessary ... . Start IV administration of D5W /SRP: "To keep open", minimal flow rate/. Use 0.9% saline (NS) or lactated Ringer's (LR) if signs of hypovolemia are present. For hypotension with signs of hypovolemia, administer fluid cautiously. Consider vasopressors if patient is hypotensive with a normal fluid volume. Watch for signs of fluid overload ... . Administer 1% solution methylene blue if patient is symptomatic with severe hypoxia, cyanosis, and cardiac compromise not responding to oxygen. ... Treat seizures with diazepam or lorazepam. ... Use proparacaine hydrochloride to assist eye irrigation ... . /Phenols and related compounds/
Currance, P.L. Clements, B., Bronstein, A.C. (Eds).; Emergency Care For Hazardous Materials Exposure. 3rd revised edition, Elsevier Mosby, St. Louis, MO 2007, p. 277

13.1.9 Human Toxicity Excerpts

/HUMAN EXPOSURE STUDIES/ ... The study aim was to assess naphthalene exposure in pregnant women from Canada, using air measurements and biomarkers of exposure. Pregnant women residing in Ottawa, Ontario completed personal and indoor air sampling, and questionnaires. During pregnancy, pooled urine voids were collected over two 24-hour periods on a weekday and a weekend day. At 2-3 months post-birth, they provided a spot urine sample and a breast milk sample following the 24-hour air monitoring. Urines were analyzed for 1-naphthol and 2-naphthol and breast milk for naphthalene. Simple linear regression models examined associations between known naphthalene sources, air and biomarker samples. Study recruitment rate was 11.2% resulting in 80 eligible women being included. Weekday and weekend samples were highly correlated for both personal (r=0.83, p<0.0001) and indoor air naphthalene (r=0.91, p<0.0001). Urine specific gravity (SG)-adjusted 2-naphthol concentrations collected on weekdays and weekends (r=0.78, p<0.001), and between pregnancy and postpartum samples (r=0.54, p<0.001) were correlated. Indoor and personal air naphthalene concentrations were significantly higher post-birth than during pregnancy (p<0.0001 for signed rank tests); concurrent urine samples were not significantly different. Naphthalene in breast milk was associated with urinary 1-naphthol: a 10% increase in 1-naphthol was associated with a 1.6% increase in breast milk naphthalene (95% CI: 0.2%-3.1%). No significant associations were observed between naphthalene sources reported in self-administered questionnaires and the air or biomarker concentrations. Median urinary concentrations of naphthalene metabolites tended to be similar to (1-naphthol) or lower (2-naphthol) than those reported in a Canadian survey of women of reproductive age. Only urinary 1-naphthol and naphthalene in breast milk were associated. Potential reasons for the lack of other associations include a lack of sources, varying biotransformation rates and behavioral differences over time.
Wheeler AJ et al; Environ Health 13 (1): 30 (2014)
/SIGNS AND SYMPTOMS/ The extensive application of 2-naphthol ointments has been responsible for systemic side effects, including vomiting and death. ...
Marzulli, F.N., H.I. Maibach. Dermatotoxicology 4th ed. New York, NY: Hemisphere Publishing Corp., 1991., p. 864
/SIGNS AND SYMPTOMS/ Ingestion can produce renal damage, vomiting, diarrhea, abdominal pain, syncope, convulsions, and hemolytic anemia.
Sullivan, J.B. Jr., G.R. Krieger (eds.). Hazardous Materials Toxicology-Clinical Principles of Environmental Health. Baltimore, MD: Williams and Wilkins, 1992., p. 1098
/CASE REPORTS/ A forty-year-old man treated with 3% 2-naphthol salve for eczema of the neck and face developed irritation of the eyes, and about a half year later was found to have opacities of the posterior cortex of both lenses.
Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 656
For more Human Toxicity Excerpts (Complete) data for 2-NAPHTHOL (7 total), please visit the HSDB record page.

13.1.10 Non-Human Toxicity Excerpts

/LABORATORY ANIMALS: Acute Exposure/ In the retinas of poisoned adult rabbits /with 2-naphthol/ spotty degeneration of the rods and cones and irregular variation in the amt of pigment in the pigment epithelium were observed. Vacuoles were present in the nuclear and nerve fiber layer and the ciliary epithelium.
Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 656
/LABORATORY ANIMALS: Acute Exposure/ An in vivo study was conducted of the biochemical pathways modulating the cataractogenicity of naphthalene. Male C57BL/6 mice and DBA/2 mice were treated with naphthalene or its metabolites and with various chemical probes that modulate critical biochemical pathways relevant to naphthalene bioactivation and detoxification. .... No cataractogenic or lethal effects from 2-naphthol were noted at dose levels of 56 or 100 mg/kg; doses of 177 and 562 mg/kg killed all the animals so exposed within 1.5 hr. ...
Wells PG et al Toxicol Appl Pharmacol 99 (3): 466-73 (1989)
/LABORATORY ANIMALS: Subchronic or Prechronic Exposure/ Experimentally in rabbits the most consistent ocular change induced by admin 2-naphthol either by stomach or by application to the skin was a development in the retina of small white shiny flecks which soon became pigmented. These became more numerous and increased in size as daily admin of the chemical continued. The retinal vessels and the iris commonly became hyperemic. The aqueous was sometimes slightly turbid, and the vitreous commonly became turbid early, but then cleared despite continuing admin of naphthol. The cornea and conjunctiva were never involved.
Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 656
/LABORATORY ANIMALS: Developmental or Reproductive Toxicity/ When 2-naphthol was admin to pregnant rabbits, the offspring had congenital cataracts, degeneration of the neuroepithelium, and hypertrophy of the retinal pigment cells.
Grant, W.M. Toxicology of the Eye. 3rd ed. Springfield, IL: Charles C. Thomas Publisher, 1986., p. 656
For more Non-Human Toxicity Excerpts (Complete) data for 2-NAPHTHOL (7 total), please visit the HSDB record page.

13.1.11 Non-Human Toxicity Values

LD50 Mouse ip 97,500 mg/kg
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 2602
LD50 Rat oral 1960 mg/kg
Lewis, R.J. Sr. (ed) Sax's Dangerous Properties of Industrial Materials. 11th Edition. Wiley-Interscience, Wiley & Sons, Inc. Hoboken, NJ. 2004., p. 2602

13.1.12 Ongoing Test Status

EPA has released the first beta version (version 0.5) of the Interactive Chemical Safety for Sustainability (iCSS) Dashboard. The beta version of the iCSS Dashboard provides an interactive tool to explore rapid, automated (or in vitro high-throughput) chemical screening data generated by the Toxicity Forecaster (ToxCast) project and the federal Toxicity Testing in the 21st century (Tox21) collaboration. /The title compound was tested by ToxCast and/or Tox21 assays; See the data in Chemical Explorer/[USEPA; ICSS Dashboard Application; Available from, as of June 27, 2014: http://actor.epa.gov/dashboard/]

13.2 Ecological Information

13.2.1 Ecotoxicity Values

LC50; Species: Daphnia magna (Water Flea) age 24 hr, juvenile, first instar; Conditions: freshwater, static, 19.5-20.5 °C; Concentration: 3540 ug/L for 48 hr (95% confidence interval: 3170-3950 ug/L)
Millemann RE et al; Trans Am Fish Soc 113 (1): 74-85 (1984) as cited in the ECOTOX database. Available from, as of October 1, 2014
LC50; Species: Micropterus salmoides (Largemouth Bass) eggs and larvae; Conditions: freshwater, flow through, 20.2-23.2 °C, pH 7.41-8.10, hardness 86.8-116.3 mg/L CaCO3, dissolved oxygen 7.1-8.4 mg/L; Concentration: 1000 ug/L for 7 days (95% confidence interval: 290-2270 ug/L)
Millemann RE et al; Trans Am Fish Soc 113 (1): 74-85 (1984) as cited in the ECOTOX database. Available from, as of October 1, 2014
LC50; Species: Micropterus salmoides (Largemouth Bass) embryo; Conditions: freshwater, flow through, 20.2-23.2 °C, pH 7.4-8.1, hardness 86.8-116.3 mg/L CaCO3, dissolved oxygen 7.1-8.4 mg/L; Concentration: 6360 ug/L for 72 hr (95% confidence interval: 5850-6910 ug/L)
Black JA et al; Fundam Appl Toxicol 3 (9-10): 353-358 (1983) as cited in the ECOTOX database. Available from, as of October 1, 2014
LC50; Species: Oncorhynchus mykiss (Rainbow Trout) embryo; Conditions: freshwater, flow through, 13.3-14.2 °C, pH 7.4-8.1, hardness 86.8-116.3 mg/L CaCO3, dissolved oxygen 8.6-10.2 mg/L; Concentration: 80 ug/L for 23 days (95% confidence interval: 60-100 ug/L)
Black JA et al; Fundam Appl Toxicol 3 (9-10): 353-358 (1983) as cited in the ECOTOX database. Available from, as of October 1, 2014
For more Ecotoxicity Values (Complete) data for 2-NAPHTHOL (6 total), please visit the HSDB record page.

13.2.2 Ecotoxicity Excerpts

/AQUATIC SPECIES/ Structure-toxicity relationships were investigated for six organic contaminants, representative of three chemical classes, likely to be found in coal conversion process waters and effluents. Using embryo-larval stages of the rainbow trout (Salmo gairdneri) and largemouth bass (Micropterus salmoides), continuous-flow toxicity tests were performed on hydroxylated aromatic hydrocarbons (phenol, beta-naphthol), azaarenes (quinoline, acridine), and polycyclic aromatic hydrocarbons (naphthalene, phenanthrene). Exposure was initiated at fertilization and maintained through 4 days post-hatching. Median lethal concentrations (LC50), based on combined frequencies of embryo-larval mortality and teratogenesis, were used to rank the toxicity of the compounds to each fish species. With the trout, the order of decreasing toxicity was phenanthrene (0.04 mg/L), beta-naphthol (0.07 mg/L), naphthalene (0.11 mg/L), phenol (0.15 mg/L), acridine (0.32 mg/L) and quinoline (11.0 mg/L). The toxicological ranking with the bass was phenanthrene (0.18 mg/L), naphthalene (0.51 mg/L), acridine (1.02 mg/L), beta-naphthol (1.77 mg/L), phenol (2.80 mg/L) and quinoline (7.50 mg/L). For each class of compounds, the chemical with the greater number of aromatic rings always exerted the greater toxicity. In tests with both fish species, beta-naphthol (two rings) was about twice as toxic as phenol (one ring), and phenanthrene (three rings) was nearly three times more toxic than naphthalene (two rings). Acridine (three rings) was seven times more toxic to bass and 34 times more toxic to trout than was quinoline (two rings). This relationship between ring number and toxicity was in excellent agreement with results from acute tests on the same compounds. Furthermore, a close correlation existed between toxicity and n-octanol:water partition coefficients within each class of compounds.
Black JA et al; Fundam Appl Toxicol 3 (5): 353-8 (1983)
/AQUATIC SPECIES/ In acute toxicity tests green algae Selenastrum capricornutum, diatoms Nitzschia palea, adult snails Physa gyrina, juvenile cladocerans Daphnia magna, larval midges Chironomus tentans, adult amphipods Gammarus minus, juvenile fathead minnows Pimephales promelas and embryo larva stages of rainbow trout Salmo gairdneri and largemouth bass Micropterus salmoides were exposed for 4 hr (algae), 48 hr (arthropods and snails), 96 hr (fathead minnows), 7 days (largemouth ) bass and 27 days (rainbow trout) to 2 phenols (phenol and beta-naphthol), 2 azaarenes (quinoline and acridine) and 2 polycyclic aromatic hydrocarbons (naphthalene and phenanthrene) present in coal derived oils. LC50 or EC50 (median effective concentrations) ranged from 0.03 mg/L for phenanthrene and rainbow trout to 286.54 mg/L for phenol and the green alga. The rainbow trout embryo larva assay was the most sensitive of the test systems to all the chemicals except quinoline. For this last compound, systems with juvenile fathead minnows and largemouth bass embryos were the more sensitive. As test systems, fish embryos and larvae were the most sensitive, juvenile fathead minnows and arthropods had intermediate sensitivity and algae and snails were the most resistant to the test compounds under the test conditions. Within each chemical class, (phenols, azaarenes and polycyclic aromatic hydrocarbons) toxicity increased with increased ring number except for the reversed relationship with the azaarenes and fathead minnows. beta-Naphthol (2 rings) was 2-45 times more toxic than phenol (1 ring); acridine (3 rings) was 7-27 times more toxic than quinoline (2 rings); and phenanthrene (3 rings) was 3-9 times more toxic than naphthalene (2 rings). There was a relationship between increases in toxicity and increases in the calculated octanol-water partition coefficients of the compounds.
Milllemann RE et al; Trans Am Fish Soc 113 (1): 74-85 (1984)

13.2.3 ICSC Environmental Data

The substance is very toxic to aquatic organisms.

13.2.4 Environmental Fate / Exposure Summary

2-Naphthol's production and use in the dye and pigments industries; as an antioxidant for fats, oils, insecticides, a chemical in the synthesis of fungicides, and an antiseptic; and in the manufacturing of medicinal organics, dyes and perfumes may result in its release to the environment through various waste streams. If released to air, an extrapolated vapor pressure of 3.2X10-4 mm Hg at 25 °C indicates 2-naphthol will exist solely as a vapor in the atmosphere. Vapor-phase 2-naphthol will be degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals; the half-life for this reaction in air is estimated to be 0.05 days. 2-Naphthol absorbs light at wavelengths >290 nm and, therefore, may be susceptible to direct photolysis by sunlight. If released to soil, 2-naphthol is expected to have moderate mobility based upon an estimated Koc of 390. The pKa of 2-naphthol is 9.51, indicating that this compound will exist partially in the anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts. Volatilization from moist soil surfaces is not expected to be an important fate process for the neutral species based upon a Henry's Law constant of 2.74X10-8 atm-cu m/mole. 2-Naphthol is not expected to volatilize from dry soil surfaces based upon its vapor pressure. Using a Chernozem soil inoculum, 2-naphthol was persistent for more than 30 days, indicating that biodegradation is not an important environmental fate process in soil. If released into water, 2-naphthol is not expected to adsorb to suspended solids and sediment based upon the estimated Koc. Utilizing the Japanese MITI test, 68.4% of the Theoretical BOD was reached in 2 weeks indicating that biodegradation is an important environmental fate process in water. Volatilization of the neutral species from water surfaces is not expected to be an important fate process based upon this compound's Henry's Law constant. An estimated BCF of 28 suggests the potential for bioconcentration in aquatic organisms is low. Hydrolysis is not expected to be an important environmental fate process since this compound lacks functional groups that hydrolyze under environmental conditions (pH 5 to 9). Occupational exposure to 2-naphthol may occur through inhalation and dermal contact with this compound at workplaces where 2-naphthol is produced or used. Monitoring data indicate that the general population may be exposed to 2-naphthol via inhalation of wood smoke containing 2-naphthol. Limited data indicate exposure may occur through dermal contact with soil. (SRC)

13.2.5 Natural Pollution Sources

2-Naphthol was detected in the emissions from the hardwoods: red maple (Acer rubrum), red oak (Quercus rubra), paper birch (Betula papyrifera) and the softwoods: white pine (Pinus strobus), hemlock (Tsuga canadensis), balsam fir (Abies balsamae) at concentrations of not detected, 0.135, 0.554, 0.348, 0.217, 0.300 mg/g OC, respectively(1). 2-Naphthol was also detected in the emissions from the hardwood species: Yellow Poplar (Liriodendron tulipifera), White Ash (Fraxinus americana), Sweet-gum (Liquidambar styracilua), Mockernut Hickory (Carya tomentosa), and the softwoods species: Loblolly pine (Pinus taeda) and Slash pine (Pinus elliottii) at concentrations of 0.206, 0.148, 0.173, 0.693, 0.471 and 0.351 mg/g OC, respectively(2).
(1) Fine PM et al; Environ Sci Technol 35: 2665-75 (2001)
(2) Fine PM et al; Environ Sci Technol 36: 1442-1451 (2002)

13.2.6 Artificial Pollution Sources

2-Naphthol's production and use in the dye and pigments industries(1); as an antioxidant for fats, oils, insecticides, a chemical in the synthesis of fungicides, and an antiseptic(2); and in the manufacturing of medicinal organics, dyes and perfumes(3) may result in its release to the environment through various waste streams(SRC).
(1) Talukder M, Kates CR; Naphthalene Derivatives. Kirk-Othmer Encyclopedia of Chemical Technology (1999-2014). New York, NY: John Wiley & Sons, Inc. Online Posting Date: December 4, 2000
(2) Lewis RJ Sr; Hawley's Condensed Chemical Dictionary 15th ed., New York, NY: John Wiley & Sons, p. 874 (2007)
(3) O'Neil MJ, ed; The Merck Index. 15th ed., Cambridge, UK: Royal Society of Chemistry p. 1189 (2013)

13.2.7 Environmental Fate

TERRESTRIAL FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.7(2) and a regression-derived equation(3), indicates that 2-naphthol is expected to have moderate mobility in soil(SRC). The pKa of 2-naphthol is 9.51(4), indicating that this compound will exist partially in the anion form in the environment and anions do not generally adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5). Volatilization of 2-naphthol from moist soil surfaces is not expected to be an important fate process for the neutral species(SRC) given a Henry's Law constant of 2.74X10-8 atm-cu m/mole(6). Using a Chernozem soil inoculum, 2-naphthol was persistent for more than 30 days(7), indicating that biodegradation is not an important environmental fate process in soil(SRC).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 66 (1995)
(3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Oct 14, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(4) Bhattacharyya D et al; Haz. Waste Haz Mater 3: 405-29 (1986)
(5) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds. Boca Raton, FL: Lewis Publ (2000)
(6) Abraham MH et al; J Pharm Sci 83: 1085-100 (1994)
(7) Medvedev VA, Davidov VD; pp 245-54 in Decomposition of Toxic and Nontoxic Organic Compounds in Soil Overcash MR, ed., Ann Arbor, MI: Ann Arbor Sci Publ (1981)
AQUATIC FATE: Based on a classification scheme(1), an estimated Koc value of 390(SRC), determined from a log Kow of 2.7(2) and a regression-derived equation(3), indicates that 2-naphthol is not expected to adsorb to suspended solids and sediment(SRC). Volatilization of the neutral species from water surfaces is not expected(4) based upon a Henry's Law constant of 2.74X10-8 atm-cu m/mole(5). According to a classification scheme(6), an estimated BCF of 28(SRC), from its log Kow and a regression-derived equation(3), suggests the potential for bioconcentration in aquatic organisms is low(SRC). Utilizing the Japanese MITI test, 68.4% of the Theoretical BOD was reached in 2 weeks(7) indicating that biodegradation is an important environmental fate process in water(SRC).
(1) Swann RL et al; Res Rev 85: 17-28 (1983)
(2) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 66 (1995)
(3) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Oct 14, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(4) Meylan WM, Howard PH; Environ Toxicol Chem 10: 1283-93 (1991)
(5) Abraham MH et al; J Pharm Sci 83: 1085-100 (1994)
(6) Franke C et al; Chemosphere 29: 1501-14 (1994)
(7) NITE; Chemical Risk Information Platform (CHRIP). Biodegradation and Bioconcentration. Tokyo, Japan: Natl Inst Tech Eval. Available from, as of Oct 27, 2014: https://www.safe.nite.go.jp/english/db.html
ATMOSPHERIC FATE: According to a model of gas/particle partitioning of semivolatile organic compounds in the atmosphere(1), 2-naphthol, which has an extrapolated vapor pressure of 3.2X10-4 mm Hg at 25 °C(2), is expected to exist solely as a vapor in the ambient atmosphere. Vapor-phase 2-naphthol is degraded in the atmosphere by reaction with photochemically-produced hydroxyl radicals(SRC); the half-life for this reaction in air is estimated to be 0.17 days(SRC), calculated from its rate constant of 1.70X10-10 cu cm/molecule-sec at 25 °C(3). 2-Naphthol absorbs light at wavelengths >290 nm(4) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).
(1) Bidleman TF; Environ Sci Technol 22: 361-367 (1988)
(2) Boublik T et al; The Vapor Pressure of Pure Substances: Selected Values of the Temperature Dependence of the Vapor Pressures of some Pure Substances in the Normal and Low Pressure Region Vol 17. Amsterdam, Netherlands: Elsevier Sci Publ p 768 (1984)
(3) Bunce NJ et al; Environ Sci Technol 31: 2252-9 (1997)
(4) NIST; NIST Chemistry WebBook. 2-Naphthalenol (135-19-3). NIST Standard Reference Database No. 69, Sept 2013 Release. Washington, DC: US Sec Commerce. Available from, as of Oct 27, 2014: https://webbook.nist.gov

13.2.8 Environmental Biodegradation

AEROBIC: 2-Naphthol, present at 100 mg/L, reached 68.4% of its theoretical BOD in 2 weeks using an activated sludge inoculum at 30 mg/L in the Japanese MITI test(1). In an OECD 301C test, 2-naphthol achieved an observed BOD of 68% after 28 days; the test substance is considered to be readily biodegradable under the conditions of the test(2). 2-Naphthol biodegraded 99.83, 99.98, 99.88, 99.90% after 100, 130, 150, 160 days, respectively, in a biodegradation study using activated sludge(3). Using adapted activated sludge as the inoculum, 2-naphthol degraded 89% based on COD removal at a biodegradation rate of 39.2 mg COD/g-hr(4). The biodegradation potential of 2-naphthol in diluted primary digested sludge was considered to be inhibitory to biodegradation after a lag period of more than 75 days(5). The 5-day BOD of 2-naphthol, present at 5 ppm, was 0.71 g/g or 27.8 of the Theoretical Oxygen Demand(6). In a Chernozem soil at 19 °C, 2-naphthol existed for > 90 days at 500 mg/kg and for 30 days at 5 mg/kg(7). 2-Naphthol is considered to be recalcitrant in Chernozem soils(8).
(1) NITE; Chemical Risk Information Platform (CHRIP). Biodegradation and Bioconcentration. Tokyo, Japan: Natl Inst Tech Eval. Available from, as of Oct 27, 2014: https://www.safe.nite.go.jp/english/db.html
(2) Sakuratani Y et al; SAR QSAR Environ Res 16: 403-431 (2005)
(3) Bosch FM, Vanvaerenbergh E; Doc Eur Sewage Refuse Symp Eas 4th pp. 272-86 (1978)
(4) Pitter P; Water Res 10: 231-5 (1976)
(5) Battersby NS, Wilson V; Appl Environ Microbiol 55: 433-9 (1989)
(6) Takemoto S et al; Suishitsu Odaku Kenkyu 4: 80-90 (1981)
(7) Medvedev VA, Davidov VD; pp 245-54 in Decomposition of Toxic and Nontoxic Organic Compounds in Soil Overcash MR, ed., Ann Arbor, MI: Ann Arbor Sci Publ (1981)
(8) Overcash MR, Pal, D; pp 182-457 in Design of Land Treatment Systems for Industrial Wastes-Theory and Practice, Ann Arbor, MI: Ann Arbor Science, pp. 182-457 (1979)
ANAEROBIC: 2-Naphthol, present at 3 mg-C/L, achieved 30% anaerobic biodegradation and 32% first stage biodegradation after 28 days(1).
(1) Kameya T et al; Sci Total Environ 170: 43-51 (1995)

13.2.9 Environmental Abiotic Degradation

The rate constant for the vapor-phase reaction of 2-naphthol with photochemically-produced hydroxyl radicals is 1.70X10-10 cu cm/molecule-sec at 25 °C(1). This corresponds to an atmospheric half-life of about 0.17 days at an atmospheric concentration of 5X10+5 hydroxyl radicals per cu cm(1). 2-Naphthol is not expected to undergo hydrolysis in the environment due to the lack of functional groups that hydrolyze under environmental conditions(2). 2-Naphthol absorbs light at wavelengths >290 nm(3) and, therefore, may be susceptible to direct photolysis by sunlight(SRC).
(1) Bunce NJ et al; Environ Sci Technol 31: 2252-9 (1997)
(2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 7-4, 7-5 (1990)
(3) NIST; NIST Chemistry WebBook. 2-Naphthalenol (135-19-3). NIST Standard Reference Database No. 69, Sept 2013 Release. Washington, DC: US Sec Commerce. Available from, as of Oct 27, 2014: https://webbook.nist.gov

13.2.10 Environmental Bioconcentration

An estimated BCF of 28 was calculated in fish for 2-naphthol(SRC), using a log Kow of 2.7(1) and a regression-derived equation(2). According to a classification scheme(2), this BCF suggests the potential for bioconcentration in aquatic organisms is low(SRC).
(1) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 66 (1995)
(2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Oct 14, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm

13.2.11 Soil Adsorption / Mobility

The Koc of 2-naphtol is estimated as 390(SRC), using a log Kow of 2.7(1) and a regression-derived equation(2). According to a classification scheme(3), this estimated Koc value suggests that 2-naphthol is expected to have moderate mobility in soil. The pKa of 2-naphthol is 9.51(4), indicating that this compound will exist partially in the anion form in the environment and anions generally do not adsorb more strongly to soils containing organic carbon and clay than their neutral counterparts(5).
(1) Hansch C et al; Exploring QSAR. Hydrophobic, Electronic, and Steric Constants. ACS Prof Ref Book. Heller SR, consult. ed., Washington, DC: Amer Chem Soc p. 66 (1995)
(2) US EPA; Estimation Program Interface (EPI) Suite. Ver. 4.1. Nov, 2012. Available from, as of Oct 14, 2014: https://www.epa.gov/oppt/exposure/pubs/episuitedl.htm
(3) Swann RL et al; Res Rev 85: 17-28 (1983)
(4) Bhattacharyya D et al; Haz. Waste Haz. Mater 3: 405-29 (1986)
(5) Doucette WJ; pp. 141-188 in Handbook of Property Estimation Methods for Chemicals. Boethling RS, Mackay D, eds. Boca Raton, FL: Lewis Publ (2000)

13.2.12 Volatilization from Water / Soil

The Henry's Law constant for 2-naphthol is as 2.74X10-8 atm-cu m/mole(1). This Henry's Law constant indicates that 2-naphthol is expected to be essentially nonvolatile from water surfaces(2). 2-Naphthol's Henry's Law constant indicates that volatilization from moist soil surfaces for the neutral species may not occur(SRC). 2-Naphthol is not expected to volatilize from dry soil surfaces(SRC) based upon an extrapolated vapor pressure of 3.2X10-4 mm Hg(3).
(1) Abraham MH et al; J. Pharm. Sci. 83: 1085-100 (1994)
(2) Lyman WJ et al; Handbook of Chemical Property Estimation Methods. Washington, DC: Amer Chem Soc pp. 15-1 to 15-29 (1990)
(3) Boublik T et al; The Vapor Pressure of Pure Substances: Selected Values of the Temperature Dependence of the Vapor Pressures of some Pure Substances in the Normal and Low Pressure Region Vol 17. Amsterdam, Netherlands: Elsevier Sci Publ p 768 (1984)

13.2.13 Environmental Water Concentrations

GROUNDWATER: 2-Naphthol was detected in the groundwater in Pensacola, FL at concentrations of 1.66, 0.62, 1.07, and 0.33 mg/L at depths of 6.1, 3.3, 5.8, and 11 meters, respectively(1). 2-Naphthol was detected at a concentration of 50 ug/L in groundwater collected from Holte Gasworks in Denmark(2).
(1) Goerlitz DF; Environ Sci Pollut Control Ser 4: 295-355 (1992)
(2) Johansen SS et al; Ground water Monit Rem 17: 106-15 (1997)

13.2.14 Effluent Concentrations

2-Naphthol was detected in the effluents of timber products industry at 559 ng/uL extract and in the effluent of printing and publishing industries at 56 ng/uL extract(1). 2-Naphthol was also detected, not quantified in wastewater from the textile industry(2).
(1) Bursey JT, Pellizzari ED; Analysis of Industrial Wastewater for Organic Pollutants in Consent Degree Survey. Contract No. 68-03-2867 Athens, GA: USEPA Environ Res Lab pp 167 (1982)
(2) Kapoor RC, Kalani SL; Vijnana Parishad Anusandhan Patrika 30: 41-7 (1987)
2-Naphthol was detected in the emissions from the combustion of scrap tires in a horizontal laboratory scale reactor at 650, 750 and 850 degrees Celsius at yields of 200, 79 and 6 mg/kg scrap tire, respectively(1). 2-Naphthol was detected in the emissions of a woodheater at 5.77 mg/kg dry wood burned with fully open airflow, 18 mg/kg dry wood burned with half-closed airflow, and 9.58 mg/kg dry wood burned with closed airflow in a S1 heater; 2-naphthol was also detected at 2.51, 5.68 and 10.7 mg/kg wood burned with an open, halfway closed and closed airflow, respectively, in a S2 heater(2).
(1) Fullana A et al; Environ Sci Technol 34: 2092-99 (2000)
(2) Jordan TB, Seen AJ; Environ Sci Technol 39: 3601-3610 (2005)

13.2.15 Sediment / Soil Concentrations

SOIL: 2-Naphthol was detected in Mainz and Berlin soils at 1.2 and 24 ng/g(1). 2-Naphthol was also detected in creosote contaminated soil at concentrations ranging from 1.1-5.5 mg/L(2).
(1) Bandowe BAM; J Environ Qual 39: 1349-1358 (2010)
(2) Meyer S et al; Anal Chem 71: 4023-9 (1999)

13.2.16 Probable Routes of Human Exposure

According to the 2012 TSCA Inventory Update Reporting data, the number of persons reasonably likely to be exposed in the industrial manufacturing, processing, and use of 2-naphthol is <10; the data may be greatly underestimated(1).
(1) US EPA; Chemical Data Reporting (CDR). Non-confidential 2012 Chemical Data Reporting information on chemical production and use in the United States. Available from, as Oct 20, 2014: https://www.epa.gov/cdr/pubs/guidance/cdr_factsheets.html
NIOSH (NOES Survey 1981-1983) has statistically estimated that 10,985 workers (590 of these were female) were potentially exposed to 2-naphthol in the US(1). Occupational exposure to 2-naphthol may occur through inhalation or other consumer products containing 2-naphthol and dermal contact with this compound at workplaces where 2-naphthol is produced or used. Monitoring data indicate that the general population may be exposed to 2-naphthol via inhalation of wood smoke. Limited data indicate exposure may occur through dermal contact with soil(SRC).
(1) NIOSH; NOES. National Occupational Exposure Survey conducted from 1981-1983. Estimated numbers of employees potentially exposed to specific agents by 2-digit standard industrial classification (SIC). Available from, as of Oct 20, 2014: https://www.cdc.gov/noes/

13.2.17 Body Burden

2-Naphthol was detected in the urine of fish consumers at concentrations of 4.4, 1.6 and 5.1 ppb from fish from Lake Michigan, Lake Huron, and Lake Erie, respectively(1). 2-Naphthol was detected with 1-naphthol at a concentration of 0.72 ug/L in amniotic fluid(2). 2-Naphthol was detected at a mean concentration of 7.85 ppb in urine collected from adults in the United States(3).
(1) Anderson HA et al; Environ Health Perspec 106: 279-89 (1998)
(2) Bradman A et al; Environ Health Perspec 111: 1179-1182 (2003)
(3) Hill RH et al; Environ Res 71: 99-108 (1995)

14 Associated Disorders and Diseases

Associated Occupational Diseases with Exposure to the Compound
Contact dermatitis, allergic [Category: Skin Disease]

15 Literature

15.1 Consolidated References

15.2 NLM Curated PubMed Citations

15.3 Springer Nature References

15.4 Thieme References

15.5 Wiley References

15.6 Nature Journal References

15.7 Chemical Co-Occurrences in Literature

15.8 Chemical-Gene Co-Occurrences in Literature

15.9 Chemical-Disease Co-Occurrences in Literature

16 Patents

16.1 Depositor-Supplied Patent Identifiers

16.2 WIPO PATENTSCOPE

16.3 Chemical Co-Occurrences in Patents

16.4 Chemical-Disease Co-Occurrences in Patents

16.5 Chemical-Gene Co-Occurrences in Patents

17 Interactions and Pathways

17.1 Protein Bound 3D Structures

17.1.1 Ligands from Protein Bound 3D Structures

PDBe Ligand Code
PDBe Structure Code
PDBe Conformer

17.2 Chemical-Target Interactions

17.3 Pathways

18 Biological Test Results

18.1 BioAssay Results

19 Taxonomy

20 Classification

20.1 MeSH Tree

20.2 NCI Thesaurus Tree

20.3 ChEBI Ontology

20.4 ChemIDplus

20.5 ChEMBL Target Tree

20.6 UN GHS Classification

20.7 EPA CPDat Classification

20.8 NORMAN Suspect List Exchange Classification

20.9 CCSBase Classification

20.10 EPA DSSTox Classification

20.11 EPA TSCA and CDR Classification

20.12 EPA Substance Registry Services Tree

20.13 MolGenie Organic Chemistry Ontology

21 Information Sources

  1. Australian Industrial Chemicals Introduction Scheme (AICIS)
  2. CAS Common Chemistry
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  6. EPA Chemicals under the TSCA
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    https://www.epa.gov/tsca-inventory
  7. EPA DSSTox
    CompTox Chemicals Dashboard Chemical Lists
    https://comptox.epa.gov/dashboard/chemical-lists/
  8. European Chemicals Agency (ECHA)
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  10. Hazardous Substances Data Bank (HSDB)
  11. Human Metabolome Database (HMDB)
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  12. ILO-WHO International Chemical Safety Cards (ICSCs)
  13. New Zealand Environmental Protection Authority (EPA)
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  14. Risk Assessment Information System (RAIS)
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  15. BindingDB
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    https://www.bindingdb.org/rwd/bind/info.jsp
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  17. Drug Gene Interaction database (DGIdb)
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    http://www.dgidb.org/downloads
  18. Toxin and Toxin Target Database (T3DB)
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  19. CCSbase
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    https://ccsbase.net/
  20. ChEBI
  21. ChEMBL
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  24. EPA Chemical and Products Database (CPDat)
  25. Hazardous Chemical Information System (HCIS), Safe Work Australia
  26. NITE-CMC
    2-Naphthol - FY2006 (New/original classication)
    https://www.chem-info.nite.go.jp/chem/english/ghs/06-imcg-1337e.html
    beta Naphthol - FY2015 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/15-meti-0016e.html
    beta Naphthol; 2-Naphthol - FY2023 (Revised classification)
    https://www.chem-info.nite.go.jp/chem/english/ghs/23-jniosh-2061e.html
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  28. FooDB
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  29. IUPAC Digitized pKa Dataset
  30. NORMAN Suspect List Exchange
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    https://creativecommons.org/licenses/by/4.0/
    2-Naphthol
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    https://www.norman-network.com/nds/SLE/
  31. MassBank Europe
  32. MassBank of North America (MoNA)
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  33. NIST Mass Spectrometry Data Center
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    https://www.nist.gov/srd/public-law
  34. SpectraBase
  35. Japan Chemical Substance Dictionary (Nikkaji)
  36. KEGG
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    https://www.kegg.jp/kegg/legal.html
  37. KNApSAcK Species-Metabolite Database
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  39. MarkerDB
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  40. Metabolomics Workbench
  41. Nature Chemistry
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  45. RCSB Protein Data Bank (RCSB PDB)
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  50. Thieme Chemistry
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  56. GHS Classification (UNECE)
  57. EPA Substance Registry Services
  58. MolGenie
    MolGenie Organic Chemistry Ontology
    https://github.com/MolGenie/ontology/
  59. PATENTSCOPE (WIPO)
CONTENTS