Hydroquinone

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Hydroquinone
Hydroquinone Crystals.jpg
Names
IUPAC name
Benzene-1,4-diol
Other names
Hydroquinone
Idrochinone
Quinol
1,4-Dihydroxybenzene
1,4-Hydroxy benzene
Properties
C6H6O2
Molar mass 110.11 g/mol
Appearance White crystalline solid
Odor Odorless
Density 1.33 g/cm3
Melting point 172 °C (342 °F; 445 K)
Boiling point 287 °C (549 °F; 560 K)
5.9 g/100 ml (15 °C)
7.2 g/100 ml (25 °C)
8.3 g/100 ml (30 °C)
Solubility Soluble in diethyl ether
Solubility in acetone 28.4 g/100 g (30 °C)
Solubility in benzene 0.06 g/100 g (30 °C)
Solubility in carbon tetrachloride 0.01 g/100 g (30 °C)
Solubility in ethanol 46.4 g/100 g (30 °C)
Vapor pressure 0.00001 mmHg (20 °C)
Acidity (pKa) 10.85
Thermochemistry
Hazards
Safety data sheet Sigma-Aldrich
Flash point 165 °C
Lethal dose or concentration (LD, LC):
490 mg/kg (mammal, oral)
245 mg/kg (mouse, oral)
200 mg/kg (rabbit, oral)
320 mg/kg (rat, oral)
550 mg/kg (guinea pig, oral)
200 mg/kg (dog, oral)
70 mg/kg (cat, oral)
Related compounds
Related compounds
Phenol
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Infobox references

Hydroquinone (C6H4(OH)2), also known as benzene-1,4-diol or quinol, is an aromatic organic compound, with a variety of uses in chemistry.

Substituted derivatives of this parent compound are also referred to as hydroquinones.

Properties

Chemical

Hydroquinone, like phenols are very weak acids and can be deprotonated.

Hydroquinone undergoes oxidation under mild conditions to give benzoquinone, process which is reversible.

Hydroquinone is highly susceptible to ring substitution by Friedel-Crafts reactions such as alkylation.

Physical

Hydroquinone is a white crystalline solid, poorly soluble in water, but more soluble in organic solvents.

Availability

HYdroquinone can be found in various skin care products. Classical photo shops also sell hydroquinone.

Hydroquinone is sold by chemical suppliers. It can also be found on eBay and Amazon.

Preparation

Hydroquinone can be made through several routes.

A common route involves hydroxylation of phenol. Hydrogen peroxide is used and the reaction gives a mixture of hydroquinone and catechol:

An accessible route involves the reaction of sodium hydroxide with 1,4-dichlorobenzene.

Projects

  • Make metol
  • Make esters

Handling

Safety

Hydroquinone is irritant.

Storage

In closed bottles.

Disposal

Can be destroyed by oxidizing it with an oxidizing mixture.

References

Relevant Sciencemadness threads