Chloral
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2008-06-25T17:47:54Z
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{{Chembox new
| Name = Chloral
| ImageFileL1 = Chloral-2D-skeletal.png
| ImageSizeL1 = 100px
| ImageNameL1 = Chloral
| ImageFileR1 = Chloral-3D-vdW.png
| ImageSizeR1 = 120px
| ImageNameR1 = Chloral
| IUPACName = Trichloroethanal
| Section1 = {{Chembox Identifiers
| CASNo = 75-87-6
| SMILES = ClC(Cl)(Cl)C=O
}}
| Section2 = {{Chembox Properties
| Formula = C<sub>2</sub>HCl<sub>3</sub>O
| MolarMass = 147.387 g/mol
| Density = 1.512 g/cm<sup>3</sup> @ 20 °C
| MeltingPt = −57.5 °C
| BoilingPt = 97.8 °C<!--refractive index (D) = 1.4557-->
| Solubility = forms soluble [[chloral hydrate|hydrate]]
| Solubility1 = miscible
| Solvent1 = ethanol
| Solubility2 = miscible
| Solvent2 = diethyl ether
| Solubility3 = miscible
| Solvent3 = chloroform
}}
}}
'''Chloral''', also known as trichloroacetaldehyde, is the [[organic compound]] with the formula Cl<sub>3</sub>CCHO. This [[aldehyde]] is a colourless oily liquid that is soluble in a wide range of solvents. It reacts with water to form [[chloral hydrate]], a once widely used [[sedative]] and [[hypnotic]] substance.
==Production==
Chloral can be produced by [[halogenation|chlorination]] of [[ethanol]], as reported in 1832 by [[Justus von Liebig]].
:4 Cl<sub>2</sub> + C<sub>2</sub>H<sub>5</sub>OH + H<sub>2</sub>O → Cl<sub>3</sub>CCH(OH)<sub>2</sub> + 5 HCl
More typically [[acetaldehyde]] is chlorinated in the presence of [[hydrogen chloride]]. Both methods yield chloral hydrate that is subsequently dehydrated by treatment with [[sulfuric acid]].<ref>Reinhard Jira, Erwin Kopp, Blaine C. McKusick, Gerhard Rõderer, Axel Bosch, Gerald Fleischmann "Chloroacetaldehydes" in Ullmann's Encyclopedia of Industrial Chemistry, Wiley-VCH, Weinheim, 2007. {{DOI|10.1002/14356007.a06 527.pub2}}.</ref>
:Cl<sub>3</sub>CCH(OH)<sub>2</sub> <math>\overrightarrow{\leftarrow}</math> Cl<sub>3</sub>CCHO + H<sub>2</sub>O
==Key reactions==
Aside from its tendency to hydrate, chloral is most notable as a building block in the synthesis of [[DDT]]. For this purpose, chloral is treated with [[chlorobenzene]] in the presence of a catalytic amount of [[sulfuric acid]]:
: Cl<sub>3</sub>CCHO + 2 C<sub>6</sub>H<sub>5</sub>Cl → Cl<sub>3</sub>CCH(C<sub>6</sub>H<sub>4</sub>Cl)<sub>2</sub> + H<sub>2</sub>O
This reaction was described by [[Othmar Zeidler]] in 1874.<ref>{{cite journal
| title = Verbindungen von Chloral mit Brom- und Chlorbenzol
| author = Othmar Zeidler
| journal = Berichte der deutschen chemischen Gesellschaft
| year = 1874
| volume = 7
| issue = 2
| pages = 1180–1181
| doi = 10.1002/cber.18740070278
}}</ref>
==References==
<references/>
[[Category:Aldehydes]]
[[Category:Organochlorides]]
{{organohalide-stub}}
[[de:Chloral]]
[[fr:Chloral]]
[[nl:Chloraal]]
[[ja:クロラール]]
[[pl:Chloral]]
[[pt:Cloral]]