Name | Hydroquinone |
Synonyms | Quinol Melanex Idrochinone HYDROQUINONE HYDROCHINONE Hydroquinone HYDROXYQUINOL Hydroxyquinone 1,4-Benzenediol benzene-1,4-diol AKOS BBS-00004220 1,4-Dihydroxybenzene 1,4-Dihydroxy benzene hydroquinone--1,4-benzenediol 6,7-dihydroxy-2H-chromen-2-one |
CAS | 123-31-9 |
EINECS | 204-617-8 |
InChI | InChI=1/C9H6O4/c10-6-3-5-1-2-9(12)13-8(5)4-7(6)11/h1-4,10-11H |
InChIKey | QIGBRXMKCJKVMJ-UHFFFAOYSA-N |
Molecular Formula | C6H6O2 |
Molar Mass | 110.11 |
Density | 1.32 |
Melting Point | 172-175°C(lit.) |
Boling Point | 285°C(lit.) |
Flash Point | 165 °C |
Water Solubility | 70 g/L (20 ºC) |
Solubility | H2O: 50mg/mL, clear |
Vapor Presure | 1 mm Hg ( 132 °C) |
Vapor Density | 3.81 (vs air) |
Appearance | Needle-Like Crystals or Crystalline Powder |
Color | White to off-white |
Exposure Limit | NIOSH REL: 15-min ceiling 2, IDLH 50; OSHA PEL: TWA 2;ACGIH TLV: TWA 2 (adopted). |
Merck | 14,4808 |
BRN | 605970 |
pKa | 10.35(at 20℃) |
Storage Condition | Store below +30°C. |
Stability | Stable. Combustible. Incompatible with strong oxidizing agents, strong bases, oxygen, ferric salts. Light and air-sensitive. Discolours in air. |
Sensitive | Air & Light Sensitive |
Refractive Index | 1.6320 |
Physical and Chemical Properties | Character: White needle crystal. melting point 172~175 ℃ boiling point 285~287 ℃ relative density 1.328g/cm3 flash point 165 ℃ solubility, ethanol and ether, benzene-soluble. |
Use | Used as imaging agent and dye, drug raw material |
Risk Codes | R22 - Harmful if swallowed R40 - Limited evidence of a carcinogenic effect R41 - Risk of serious damage to eyes R43 - May cause sensitization by skin contact R50 - Very Toxic to aquatic organisms R68 - Possible risk of irreversible effects |
Safety Description | S26 - In case of contact with eyes, rinse immediately with plenty of water and seek medical advice. S36/37/39 - Wear suitable protective clothing, gloves and eye/face protection. S61 - Avoid release to the environment. Refer to special instructions / safety data sheets. |
UN IDs | 2662 |
WGK Germany | 3 |
RTECS | MX3500000 |
TSCA | Yes |
HS Code | 29072210 |
Hazard Class | 9 |
Packing Group | III |
Toxicity | LD50 orally in rats: 320 mg/kg (Woodard) |
White needle-like crystals. Soluble in alcohol and ether, soluble in water, slightly soluble in benzene. Visible light in the air easily turned to light red. The aqueous solution can be oxidized to Brown in air. Flammable in case of open flame and high heat. Reactions with strong oxidants may occur. By high heat decomposition of toxic gases. Hydroquinone is a weak acid. It reacts with most of the oxidizing agents and is converted to O-and p-benzoquinones. Hydroquinone has a, beta and gamma; Three crystal forms. Type A is a triangular needle-like or diamond-like crystal, crystallized from water and stable. Lu is a triangular crystal, crystallized from methanol, unstable. The & gamma; Type is monoclinic crystal, which is obtained by sublimation method and is unstable. All three crystals can be rubbed to emit fluorescence. Hydroquinone is flammable, but the flash point is high, the vapor pressure is low, if there is no fire, the risk is not big.
aniline is oxidized to p-benzoquinone with manganese dioxide in sulfuric acid medium and then reduced to hydroquinone with iron powder.
In the field of water treatment, hydroquinone is added to the hot water and cooling water of the closed-circuit heating and cooling system, and the corrosion inhibition of the water side Metal energy is carried out. Hydroquinone is used as an oxygen scavenger for boiler water, and hydroquinone is added thereto to remove residual dissolved oxygen when the boiler water is preheated for oxygen removal.
rat oral LD50:320mg/kg. Hydroquinone is toxic and flammable. The reduction of hydroquinone is very strong, and it is easy to be oxidized to p-benzoquinone. Hydroquinone is toxic and can cause poisoning through the skin. The oral lethal dose was 0.08-0. 2g/kg. If the oral administration of more than 1g will appear symptoms of acute poisoning, taking 59g can be fatal. In Japan, the maximum allowable concentration of hydroquinone in the air of the production workshop is 2mg/ma. When hydroquinone contact the skin, eyes, immediately with water or saline rinse. According to the relevant information, hydroquinone has a potential carcinogenic effect. Store in a cool, ventilated warehouse. Keep away from fire and heat source. Protection from direct sunlight. Keep the container sealed. Protected from light. It should be stored separately from oxidant, acids and edible chemical raw materials.