Thionyl chloride
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2008-06-23T01:50:04Z
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{{Chembox new
| Name = Thionyl chloride
| ImageFile = Thionyl-chloride-2D-dimensions.png
| ImageName = Structure of thionyl chloride
| ImageFile1 = Thionyl-chloride-3D-vdW.png
| ImageName1 = 3D model of thionyl chloride
| OtherNames = sulfurous oxychloride<br />sulfurous dichloride<br />sulfinyl chloride<br />sulfinyl dichloride<br />dichlorosulfoxide
| Section1 = {{Chembox Identifiers
| CASNo = 7719-09-7
}}
| Section2 = {{Chembox Properties
| Formula = SOCl<sub>2</sub>
| MolarMass = 118.97 g/mol
| Appearance = clear to yellow<br />odorous liquid
| Density = 1.638 g ml<sup>−1</sup>, liquid
| Solubility = Reactive
| MeltingPt = −104.5 °C
| BoilingPt = 76 °C
| Viscosity = 0.6 [[Poise|cP]] at ? °C
}}
| Section3 = {{Chembox Structure
| MolShape = pyramidal
| Dipole = 1.4 [[Debye|D]]
}}
| Section7 = {{Chembox Hazards
| ExternalMSDS = [http://ptcl.chem.ox.ac.uk/MSDS/TH/thionyl_chloride.html External MSDS]
| EUClass = Corrosive ('''C''')
| NFPA-H = 4
| NFPA-F = 0
| NFPA-R = 2
| NFPA-O = W
| RPhrases = {{R14}}, {{R20/22}}, {{R29}}, {{R35}}
| SPhrases = {{S1/2}}, {{S26}}, {{S36/37/39}}, {{S45}}
| FlashPt = non flammable
}}
| Section8 = {{Chembox Related
| OtherCpds = [[Sulfuryl chloride]]<br />[[Selenium oxydichloride]]
}}
}}
'''Thionyl chloride''' (or '''thionyl dichloride''') is an [[inorganic compound]] with the [[chemical formula|formula]] [[Sulfur|S]][[Oxygen|O]][[Chlorine|Cl]]<sub>2</sub>. SOCl<sub>2</sub> is a reactive chemical [[reagent]] used in chlorination [[chemical reaction|reactions]]. It is a colorless, distillable [[liquid]] at room [[temperature]] and [[pressure]] that decomposes above 140 °C. SOCl<sub>2</sub> is sometimes confused with [[sulfuryl chloride]], SO<sub>2</sub>Cl<sub>2</sub>, but the chemical properties of these S(IV) and S(VI) compounds differ significantly.
==Properties and structure==
The molecule SOCl<sub>2</sub> is pyramidal, indicating the presence of a lone pair of electrons on the S(IV) center. In contrast, [[phosgene|COCl<sub>2</sub>]] is planar.
SOCl<sub>2</sub> reacts with water to release hydrogen chloride and sulfur dioxide.
:[[Water (molecule)|H<sub>2</sub>O]] + O=SCl<sub>2</sub> → [[sulfur dioxide|SO<sub>2</sub>]] + 2 [[hydrogen chloride|HCl]]
Because of its high reactivity toward water, SOCl<sub>2</sub> would not be expected to occur in nature.
==Production==
The major industrial synthesis involves the reaction of [[sulfur trioxide]] and [[sulfur dichloride]]:<ref>N. N. Greenwood, A. Earnshaw, ''Chemistry of the Elements'', Pergamon Press, 1984.</ref>
:[[Sulfur trioxide|SO<sub>3</sub>]] + [[Sulfur dichloride|SCl<sub>2</sub>]] → '''SOCl<sub>2</sub>''' + SO<sub>2</sub>.
Other methods include
:SO<sub>2</sub> + [[Phosphorus pentachloride|PCl<sub>5</sub>]] → '''SOCl<sub>2</sub>''' + POCl<sub>3</sub>;
:SO<sub>2</sub> + [[Chlorine|Cl<sub>2</sub>]] + SCl<sub>2</sub> → 2 '''SOCl<sub>2</sub>''';
:[[Sulfur trioxide|SO<sub>3</sub>]] + Cl<sub>2</sub> + 2 SCl<sub>2</sub> → 3 '''SOCl<sub>2</sub>'''.
The first of the above three reactions also affords [[phosphoryl chloride|phosphorus oxychloride]] (or phosphoryl chloride), which resembles thionyl chloride in many of its reactions.
==Applications==
Thionyl chloride is used inside lithium-thionyl chloride [[battery (electricity)|batteries]] as the positive active material with [[lithium]] as the negative active material. It is also used as a reagent for the production of other [[chemical compound]]s or materials.
In military usage, thionyl chloride is used in the "di-di" method of producing G-series [[nerve agent]]s.
===Organic chemistry===
Thionyl chloride is widely used to convert [[carboxylic acid]]s to [[acyl chloride]]s <ref>{{OrgSynth | author = Allen, C. F. H.; Byers, Jr., J. R.; Humphlett, W. J. | collvol = 4 | collvolpages = 739 | year = 1963 | title = Oleoyl chloride | prep = cv4p0739}}</ref><ref>{{OrgSynth | author = Rutenberg, M. W.; Horning, E. C. | collvol = 4 | collvolpages = 620 | year = 1963 | title = 1-Methyl-3-ethyloxindole | prep = cv4p0620}}</ref>
:[[Image:CarbonylicAcidThionylChlorideReaction.svg|CarbonylicAcidThionylChlorideReaction]]
and [[alcohol]]s <ref>{{OrgSynth | author = Mondanaro, K. R.; Dailey, W. P. | collvol = 10 | collvolpages = 212 | year = 2004 | title = 3-Chloro-2-(chloromethyl)-1-propene | prep = v75p0089}}</ref><ref>{{OrgSynth | author = Krakowiak, K. E.; Bradshaw, J. S. | collvol = 9 | collvolpages = 34 | year = 1998 | title = 4-Benzyl-10,19-diethyl-4,10,19-triaza-1,7,13,16-tetraoxacycloheneicosane | prep = cv9p0034}}</ref> to the corresponding alkyl chlorides via an [[SNi reaction|internal nucleophilic substitution]].
:[[Image:AlcoholThionylChlorideReaction.svg|Alcohol Thionyl Chloride Reaction]]
It is preferred over other reagents such as [[phosphorus pentachloride]] because the products of the thionyl chloride reactions, HCl and SO<sub>2</sub> are gaseous, simplifying the purification of the product. Excess thionyl chloride may be removed by [[distillation]]. An example of a reaction of thionyl chloride with an alcohol is in a synthesis of [[bicifadine]] <ref>''Chlorination/Cyclodehydration of Amino Alcohols with SOCl2: An Old Reaction Revisited'' Feng Xu, Bryon Simmons, Robert A. Reamer, Edward Corley, Jerry Murry, and David Tschaen [[J. Org. Chem.]] '''2008''', 73, 312-315 {{DOI|10.1021/jo701877h}}</ref>:
:[[Image:BicifadineSynthesisXu2007.svg|Bicifadine Synthesis Xu 2007]]
[[Sulfonic acid]]s react with thionyl chloride to produce [[sulfonyl chloride]]s.<ref>{{OrgSynth | author = Weinreb, S. M.; Chase, C. E.; Wipf, P.; Venkatraman, S. | collvol = 10 | collvolpages = 707 | year = 2004 | title = 2-Trimethylsilylethanesulfonyl chloride (SES-Cl) | prep = v75p0161}}</ref><ref>{{OrgSynth | author = Hazen, G. G.; Bollinger, F. W.; Roberts, F. E.; Russ, W. K.; Seman, J. J.; Staskiewicz, S. | collvol = 9 | collvolpages = 400 | year = 1998 | title = 4-Dodecylbenzenesulfonyl azides | prep = cv9p0400}}</ref> Likewise, thionyl chloride will transform [[sulfinic acid]]s into [[sulfinyl chloride]]s<ref>{{OrgSynth | author = Hulce, M.; Mallomo, J. P.; Frye, L. L.; Kogan, T. P.; Posner, G. H. | collvol = 7 | collvolpages = 495 | year = 1990 | title = (S)-( + )-2-(p-toluenesulfinyl)-2-cyclopentenone: Precursor for enantioselective synthesis of 3-substituted cyclopentanones | prep = cv7p0495}}</ref><ref>{{OrgSynth | author = Kurzer, F. | collvol = 4 | collvolpages = 937 | year = 1963 | title = ''p''-Toluenesulfinyl chloride | prep = cv4p0937}}</ref> and [[phosphonic acid]]s into [[phosphoryl chloride]]s.
Thionyl chloride will react with primary [[formamide]]s to form [[isocyanide]]s.<ref>{{OrgSynth | author = Niznik, G. E.; Morrison, III, W. H.; Walborsky, H. M. | collvol = 6 | collvolpages = 751 | year = 1988 | title = 1-d-Aldehydes from organometallic reagents: 2-methylbutanal-1-d | prep = cv6p0751}}</ref>
[[Amide]]s will react with thionyl chloride to form [[imidoyl chlorides]]. However, primary amides under heating with thionyl chloride will continue on to form [[nitrile]]s.<ref>{{OrgSynth | author = Krynitsky, J. A.; Carhart, H. W. | collvol = 4 | collvolpages = 436 | year = 1963 | title = 2-Ethylhexanonitrile | prep = cv4p0436}}</ref>
===Inorganic chemistry===
[[Anhydrous]] metal chlorides may be obtained from hydrated metal chlorides by refluxing in freshly distilled thionyl chloride:<ref>{{cite journal | title = Anhydrous Metal Chlorides | author = Alfred R. Pray, Richard F. Heitmiller, Stanley Strycker | journal = [[Inorganic Syntheses]] | volume = 28 | pages = 321–323 | doi = 10.1002/9780470132593.ch80 | year = 1990}}</ref>
:MCl<sub>n</sub>·xH<sub>2</sub>O + x SOCl<sub>2</sub> → MCl<sub>n</sub> + x SO<sub>2</sub> + 2x HCl
==Safety==
SOCl<sub>2</sub> is [[toxic]], [[corrosive]], and [[lachrymatory]]. It is a [[skin]] and [[inhalation]] hazard, as well as being odorous. It can react explosively when exposed to high concentrations of nucleophiles such as [[phosphites]].
Industrial production of thionyl chloride is controlled under the [[Chemical Weapons Convention]], where it is listed in [[List of Schedule 3 substances (CWC)|schedule 3]].
==References==
<div class="references-small"><references /></div>
==External links==
* Usage of [http://www.orgsyn.org/orgsyn/chemname.asp?nameID=32837 thionyl chloride] in [[Organic Syntheses]]
*{{ICSC|1409|14}}
*[http://www.cdc.gov/niosh/npg/npgd0611.html NIOSH Pocket Guide to Chemical Hazards]
[[Category:Chlorides]]
[[Category:Thionyl compounds]]
[[Category:Acyl chlorides]]
[[Category:Nonmetal halides]]
[[Category:Reagents for organic chemistry]]
[[Category:Inorganic sulfur compounds]]
[[Category:lachrymatory agents]]
[[cs:Chlorid thionylu]]
[[de:Thionylchlorid]]
[[es:Cloruro de tionilo]]
[[fr:Chlorure de thionyle]]
[[it:Cloruro di tionile]]
[[nl:Thionylchloride]]
[[ja:塩化チオニル]]
[[pl:Chlorek tionylu]]
[[pt:Cloreto de tionila]]
[[ru:Тионилхлорид]]
[[sv:Tionylklorid]]
[[zh:氯化亚砜]]