Oxalyl chloride 1619799 224095669 2008-07-07T08:05:24Z Puppy8800 5404759 iw {{Chembox new | Name = Oxalyl chloride | ImageFile = Oxalyl-chloride-2D.png <!-- | ImageSize = 150px --> | ImageName = Oxalyl chloride | IUPACName = Oxalyl dichloride | OtherNames = Ethanedioyl dichloride<br />Oxalic acid chloride<br />Oxalic acid dichloride<br />Oxalyl dichloride<br />Oxalic dichloride<br />Oxaloyl chloride | Section1 = {{Chembox Identifiers | SMILES = ClC(=O)C(=O)Cl | CASNo = 79-37-8 | RTECS = KI2950000 }} | Section2 = {{Chembox Properties | Formula = C<sub>2</sub>O<sub>2</sub>Cl<sub>2</sub> | MolarMass = 126.93 g/mol | Appearance = colorless liquid | Density = 1.4785 g/mL, liquid | Solubility = Decomposes | MeltingPt = &minus;16 °C | BoilingPt = 63&ndash;64 °C (1.017 bar) | Viscosity = | RefractIndex = 1.429 }} | Section7 = {{Chembox Hazards | ExternalMSDS = [http://ptcl.chem.ox.ac.uk/MSDS/OX/oxalyl_chloride.html External MSDS] | EUClass = not listed | NFPA-H = 3 | NFPA-F = | NFPA-R = 1 }} | Section8 = {{Chembox Related | Function = [[acyl chloride]]s | OtherFunctn = [[Malonyl chloride]]<br />[[Succinyl chloride]]<br /> [[phosgene]] | OtherCpds = [[Oxalic acid]]<br /> [[Diethyl oxalate]]<br /> [[Oxamide]]<br /> [[Oxalyl hydrazide]]</br>[[Cuprizon 1]] }} }} '''Oxalyl chloride''' is a [[chemical compound]] with the [[chemical formula|formula]] (COCl)<sub>2</sub>. This colourless liquid, the di[[acid chloride]] of [[oxalic acid]], is a useful reagent in [[organic synthesis]].<ref>Salmon, R. "Oxalyl Chloride" in Encyclopedia of Reagents for Organic Synthesis 2001, John Wiley & Sons, New York.DOI: 10.1002/047084289X.ro015</ref> It can be prepared by treating [[oxalic acid]] with [[phosphorus pentachloride]].<ref>Vogel, A.; Steffan, G.; Mannes, K.; Trescher, V. "Oxalyl chloride" DE 78-2840435 19780916.Chemical Abstracts Number 93:94818</ref> ==Applications in organic synthesis== ====Synthesis of acid chlorides==== It is mainly used in [[organic synthesis]] for the preparation of acid chlorides from the corresponding [[carboxylic acid]]s. Like [[thionyl chloride]], the reagent produces volatile side products in this application: :RCO<sub>2</sub>H + (COCl)<sub>2</sub> → RC(O)Cl + HCl + [[carbon monoxide|CO]] + [[carbon dioxide|CO<sub>2</sub>]] Oxalyl chloride tends to be a milder, more selective [[reagent]]. ====Formylation of arenes==== Oxalyl chloride reacts with [[aromatic ring|aromatic]] compounds in the presence of [[aluminium chloride]] to give the corresponding [[acid chloride]] in a process known as a [[Friedel-Crafts acylation]].<ref>{{OrgSynth | author = Neubert, M. E.; Fishel, D. L. | title = Preparation of 4-Alkyl- and 4-Halobenzoyl Chlorides: 4-Pentylbenzoyl Chloride |collvol = 7 | collvolpages = 420 | year = 1990 | prep = cv7p0420}}</ref><ref>{{OrgSynth | author = Sokol, P. E. | title = Mesitoic Acid | collvol = 5 | collvolpages = 706 | year = 1973 | prep = CV5P0706}}</ref> The resulting acid chloride can be hydrolysed in water to form the corresponding [[carboxylic acid]]. ====Preparation of diesters==== Like other acid chlorides, oxalyl chloride reacts with alcohols to give esters: :2 RCH<sub>2</sub>OH + (COCl)<sub>2</sub> → RCH<sub>2</sub>OC(O)C(O)OCH<sub>2</sub>R + 2 HCl Typically such reactions are conducted in the presence of a base such as [[pyridine]]. The diester derived from [[phenol]], [[phenyl oxalate ester]], is Cyalume, the active ingredient in [[glow sticks]]. ====Oxidation of alcohols==== The combination of [[Dimethyl sulfoxide|DMSO]] and oxalyl chloride converts alcohols to the corresponding [[aldehyde]]s and [[ketone]]s via the process known as the [[Swern oxidation]]. ==Precautions== As with all [[acyl chloride]]s, oxalyl chloride reacts with [[water (molecule)|water]] liberating [[hydrogen chloride|HCl]] gas. Overall, its effects are comparable to those of [[phosgene]]. In March 2000 a [[Malaysia Airlines]] [[Airbus A330]] was damaged beyond repair after a falsely declared cargo of oxalyl chloride leaked into the cargo bay. <ref>{{cite news | title = Firm told to pay $65 mln for ruining plane | date = 2007-12-06 | url = http://www.reuters.com/article/oddlyEnoughNews/idUSN0620441720071206 | publisher=[[Reuters]] | accessdate=2007-12-06}}</ref> ==References== <references/> [[Category:Acyl chlorides]] [[de:Oxalylchlorid]] [[fr:chlorure d'oxalyle]] [[nl:Oxalylchloride]] [[ja:塩化オキサリル]] [[pl:Chlorek oksalilu]] [[zh:草酰氯]]