| IUPAC name
| Other names
|Molar mass||108.10 g/mol|
|Density||1.318 g/cm3 (at 20 °C)|
|Melting point||115 °C (239 °F; 388 K)|
|1.1 g/100 ml (18 °C)|
|Solubility|| Soluble in acetone|
Slightly soluble in benzene, diethyl ether, ethanol, petroleum ether
|Vapor pressure||0.1 mmHg at 25 °C|
|Safety data sheet||Sigma-Aldrich|
|Lethal dose or concentration (LD, LC):|
LD50 (Median dose)
| 130 mg/kg (rat, oral)|
25 mg/kg (mouse, oral)
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
1,4-Benzoquinone, commonly known as para-quinone, is a chemical compound with the formula C6H4O2. In a pure state, it forms bright-yellow crystals with a characteristic irritating odor. This six-membered ring compound is the oxidized derivative of hydroquinone. The molecule is multifunctional: it exhibits properties of a ketone, forming an oxime; an oxidant, forming the dihydroxy derivative; and an alkene, undergoing addition reactions, especially those typical for α,β-unsaturated ketones. 1,4-Benzoquinone is sensitive toward both strong mineral acids and alkali, which cause condensation and decomposition of the compound.
It is an isomer of 1,2-benzoquinone.
Benzoquinone forms bright yellow needle-like crystals. It is soluble in acetone and some organic solvents, but nearly insoluble in water and most polar solvents.
Benzoquinone readily undergoes sublimation, even at room temperature.
1,4-Benzoquinone is sold by chemical suppliers.
Benzoquinone can be prepared by oxidation of hydroquinone.
- Make hydroquinone
- Make hydroxyquinol triacetate
Benzoquinone vapors are very irritating to the eyes and to the respiratory system. Handle in a well ventilated area, ideally in a fume cupboard.
Skin contact can result in brown staining, and apparently even localized tissue necrosis in severe cases. Benzoquinone is potentially a skin sensitizer.
Benzoquinone is probably carcinogenic.
Benzoquinone should be kept in tightly-closed glass bottles, such as flasks with a ground glass joint, or glass bottles with a PTFE seal cap. Plastic containers are unsuitable for storing this compound, as it stains/degrades polyethylene containers.
Can be destroyed by oxidizing it with an oxidizing mixture, though due to its strong odor, this must be done outside or in a fumehood.