HydroquinoneCAS#123-31-9
1. Potent Reducing Agent: Highly effective reducing properties make it invaluable as a photographic developer and antioxidant in rubber, polymers, and industrial processes.
2. Versatile Solubility Profile: Good solubility in hot water, ethanol, and ether facilitates formulation across cosmetic, industrial, and chemical synthesis applications.
3. Skin Depigmentation Efficacy: Clinically proven ability to inhibit melanin production, making it a key active ingredient in topical treatments for hyperpigmentation (subject to regulatory approval).
4. Established Industrial Utility: Long history of safe, regulated use in polymerization inhibitors, stabilizers, and as a chemical intermediate, supported by clear handling guidelines.
Hydroquinone, alternatively known as quinol or 1,4-dihydroxybenzene, has the molecular formula C6H6O2 and a molecular weight of 110.11. It appears as colorless or white crystalline solid that readily undergoes discoloration when exposed to air and light. Its water-based solution oxidizes to form brown coloration in air, with oxidation occurring more rapidly under alkaline conditions.
The compound has a melting point of 170-171°C, boiling point of 285-287°C, relative density of 1.332 (at 15°C), and exhibits maximum UV absorption at 288nm in aqueous solution. It shows high solubility in hot water, ethanol and diethyl ether, but only limited solubility in benzene. Chemically reactive, it is particularly prone to oxidation and can participate in various reactions including esterification and substitution reactions.
Melting point | 172-175 °C(lit.) |
Boiling point | 285 °C(lit.) |
density | 1.32 |
vapor density | 3.81 (vs air) |
vapor pressure | 1 mm Hg ( 132 °C) |
refractive index | 1.6320 |
Fp | 165 °C |
storage temp. | Store below +30°C. |
solubility | H2O: 50 mg/mL, clear |
pka | 10.35(at 20℃) |
form | Needle-Like Crystals or Crystalline Powder |
color | White to off-white |
Odor | odorless |
Water Solubility | 70 g/L (20 ºC) |
Sensitive | Air & Light Sensitive |
Merck | 14,4808 |
BRN | 605970 |
Henry's Law Constant | (x 10-9 atm?m3/mol): <2.07 at 20 °C (approximate - calculated from water solubility and vapor pressure) |
Exposure limits | NIOSH REL: 15-min ceiling 2, IDLH 50; OSHA PEL: TWA 2; ACGIH TLV: TWA 2 (adopted). |
Stability: | Stable. Combustible. Incompatible with strong oxidizing agents, strong bases, oxygen, ferric salts. Light and air-sensitive. Discolours in air. |
InChIKey | QIGBRXMKCJKVMJ-UHFFFAOYSA-N |
LogP | 0.59 at 20℃ |
CAS DataBase Reference | 123-31-9(CAS DataBase Reference) |
NIST Chemistry Reference | Hydroquinone(123-31-9) |
IARC | 3 (Vol. 15, Sup 7, 71) 1999 |
EPA Substance Registry System | Hydroquinone (123-31-9) |
Safety Information
Hazard Codes | Xn,N |
Risk Statements | 22-40-41-43-50-68-R68-R50-R43-R41-R40-R22 |
Safety Statements | 26-36/37/39-61-S61-S36/37/39-S26 |
RIDADR | 2662 |
WGK Germany | 3 |
RTECS | MX3500000 |
Autoignition Temperature | 930 °F |
TSCA | Yes |
HazardClass | 9 |
PackingGroup | III |
HS Code | 29072210 |
Hazardous Substances Data | 123-31-9(Hazardous Substances Data) |
Toxicity | LD50 orally in rats: 320 mg/kg (Woodard) |
IDLA | 50 mg/m3 |
