Ingredient Dictionary

2-NAPHTHOL

2-naphthol is a naphthol carrying a hydroxy group at position 2.

Definition

2-naphthol is a naphthol carrying a hydroxy group at position 2. It has a role as an antinematodal drug, a radical scavenger, a genotoxin, a mouse metabolite, a human xenobiotic metabolite and a human urinary metabolite.

Source: PubChem

US FDA substance register · UNII P2Z71CIK5H · registered name 2-Naphthol · single chemical substance

Source: US FDA Unique Ingredient Identifier (UNII)

Cosmetic roles

Gives the product a scentPERFUMINGDyes hairHAIR DYEING

Safety & regulatory references

Banned: Argentina · ASEAN · Brazil · Canada · China · European Union · South Korea · United Kingdom

Source: ASEAN Cosmetic Directive · EU Cosmetics Regulation · Health Canada Cosmetic Ingredient Hotlist · MFDS (Korea) cosmetic regulatory information · UK cosmetics regulations (OPSS)

Korea’s toxic-substance GHS classification: Warning · H400 (category 1) · H317 (category 1) · H319 (category 2) · +2 more

Source: Korea toxic substances GHS register (NIER)

EU Cosmetics Regulation, Annex II (prohibited substances), entry 241

Source: EU prohibited substances (Annex II)

Health Canada Cosmetic Ingredient Hotlist · prohibited in cosmetics

Source: Health Canada Cosmetic Ingredient Hotlist

Restriction II/241 · Other restriction: ban substances that deplete the ozone layer

Source: EU CosIng ingredient list

More data — names, identifiers, properties, test records, literature

Names & identifiers

2-NAPHTHOLINCI2-나프톨Korean label name (MFDS standard)2-NaphthalenolSynonym

CAS No.chemical registry number: 135-19-3
EC No.EU chemical inventory number: 205-182-7
DTXSIDUS EPA chemical ID: DTXSID5027061
DTXCIDUS EPA compound ID: DTXCID907061

IUPAC: Naphthalen-2-ol
Molecular formula: C10H8O
Molecular weight: 144.173 g/mol

Measured properties

Appearance: Liquid, CBI, Other Solid, Dry Powder · White solid, Darkens upon aging and exposure to sunlight, [Hawley] Tan chips with a phenol-like odor, [MSDSonline]
Odour: Faint phenol-like odor
Boiling point: 285 °C · 285.00 to 286.00 °C. @ 760.00 mm Hg
Melting point: 121.6 °C · 123 °C
Solubility: In water, 7.55X10+2 mg/L at 25 °C · Soluble in alcohol, ether, chloroform, glycerol, oils, alkaline solutions
Density: 1.28 g/cu cm at 20 °C · 1.28 g/cm³
Stability: Stable under recommended storage conditions.
Dissociation constant: pKa = 9.51 at 25 °C
Colour: white
Odour threshold: 0.01-11.4 ppm
Melting/freezing point: 121 ℃
Initial boiling point and range: 285 ℃
Flash point: 153 ℃
Vapour pressure: 1.4 ㎩ (at 20 ℃)
Water solubility: 0.074 g/100㎖ (at 25 ℃)
Vapour density: 5
Relative density: 1.28 (at 20 ℃)
n-Octanol/water partition coefficient (Kow): 2.7 (2.01-2.84)
Auto-ignition temperature: 550 ℃
Molecular weight: 144.17

Values measured on the substance itself. The KOSHA data are a reference for writing and reviewing safety data sheets, not a specification for a commercial raw material.

Source: PubChem · KOSHA safety data sheets (Korea)

What products actually use it for

What the 7 products reported to the US EPA with this ingredient use it for. Products outside cosmetics are included, so the top few rows are its main uses.

Dye3
Intermediate2
Pigment1
Fragrance1

Source: US EPA CompTox dashboard

Irritation and sensitisation studies

3 skin studies and 2 eye studies are on record.

Classed as low1

The study conclusions largely agree (100%). These tests are on the raw material itself; irritation at the amount in a finished product is a different question.

See all 5 studies

Skin sensitization - Category 1B
Skin Sensitization · Screening
Category 1
Skin Sensitization · Screening
Not classified
Skin Irritation · Screening
Category 2A
Eye Irritation · Screening
Serious eye damage/eye irritation - Category 2A
Eye Irritation · Screening