Hydroquinone
CAS 123-31-9C6H6O2110.11 g/mol
Hydroquinone is a benzenediol comprising benzene core carrying two hydroxy substituents para to each other. It has a role as an antioxidant, a cofactor, a carcinogenic agent, a mouse metabolite, a human xenobiotic metabolite, an Escherichia coli metabolite and a skin lightening agent. It is a benzenediol and a member of hydroquinones.
IUPAC: benzene-1,4-diol
PubChem
Physical & Chemical Properties
| Melting Point | 338 to 340 °F (EPA, 1998) |
| Boiling Point | 545 to 549 °F at 760 mmHg (EPA, 1998) |
| Density | 1.332 at 59 °F (EPA, 1998) - Denser than water; will sink |
| Solubility | 10 to 50 mg/mL at 68 °F (NTP, 1992) |
| Flash Point | 329 °F (EPA, 1998) |
| Vapor Pressure | 4 mmHg at 302 °F (EPA, 1998) |
| Appearance | Hydroquinone appears as light colored crystals or solutions. May irritate the skin, eyes and mucous membranes. Mildly toxic by ingestion or skin absorption. |
Data: PubChem · Last updated: 4/20/2026
GHS Classification
No GHS classification data available.
Classification data is sourced from ECHA.
Regulatory Compliance
TSCA
Listed
note: Status based on EPA TSCA Active Inventory · inventory name: TSCA Chemical Substance Inventory
View sourceGlobal Trade Intelligence
No trade flow data available for this chemical.
HS Code(s): 2907
Data: UN Comtrade
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