Oxalyl chloride

Oxalyl chloride
	Oxalyl chloride
	Carbon, C Oxygen, O Chlorine, Cl
Names
	Preferred IUPAC name Oxalyl dichloride
	Systematic IUPAC name Ethanedioyl dichloride
	Other names Oxalic acid chloride; Oxalic acid dichloride (1:2); Oxalic dichloride; Oxaloyl chloride;
Identifiers
CAS Number	79-37-8 ;
3D model (JSmol)	Interactive image;
ChemSpider	59021 ;
ECHA InfoCard	100.001.092
EC Number	201-200-2;
PubChem CID	65578;
RTECS number	KI2950000;
UNII	R4Y96317DW ;
CompTox Dashboard (EPA)	DTXSID3058822 ;
	InChI InChI=1S/C2Cl2O2/c3-1(5)2(4)6 Key: CTSLXHKWHWQRSH-UHFFFAOYSA-N ; InChI=1/C2Cl2O2/c3-1(5)2(4)6 Key: CTSLXHKWHWQRSH-UHFFFAOYAG;
	SMILES ClC(=O)C(=O)Cl;
Properties
Chemical formula	C2O2Cl2
Molar mass	126.92 g·mol−1
Appearance	Colorless liquid
Odor	Phosgene-like
Density	1.4785 g/mL
Melting point	−16 °C (3 °F; 257 K)
Boiling point	63 to 64 °C (145 to 147 °F; 336 to 337 K) at 1.017 bar
Solubility in water	Reacts
Refractive index (nD)	1.429
Hazards
	Occupational safety and health (OHS/OSH):
Main hazards	Toxic, corrosive, lachrymator
	GHS labelling:
Pictograms
Signal word	Danger
Hazard statements	H314, H331
Precautionary statements	P261, P280, P305+P351+P338, P310
NFPA 704 (fire diamond)	3 1 2 W
Safety data sheet (SDS)	External MSDS
Related compounds
Related acyl chlorides	Malonyl chloride; Succinyl chloride; Phosgene;
Related compounds	Oxalic acid; Diethyl oxalate; Oxamide; Oxalyl hydrazide; Cuprizon 1;
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). verify (what is ?) Infobox references

Oxalyl chloride is an organic chemical compound with the formula Cl−C(=O)−C(=O)−Cl. This colorless, sharp-smelling liquid, the diacyl chloride of oxalic acid, is a useful reagent in organic synthesis.^[4]

Preparation

Oxalyl chloride was first prepared in 1892 by the French chemist Adrien Fauconnier, who treated diethyl oxalate with phosphorus pentachloride.^[5] It can also be prepared by treating oxalic acid with phosphorus pentachloride.^[6]^[7]

Oxalyl chloride is produced commercially from ethylene carbonate. Photochlorination gives the perchloroethylene carbonate C₂Cl₄O₂CO and hydrogen chloride HCl, which is subsequently degraded to oxalyl chloride and phosgene COCl₂:^[8]

C₂H₄O₂CO + 4 Cl₂ → C₂Cl₄O₂CO + 4 HCl

C₂Cl₄O₂CO → C₂O₂Cl₂ + COCl₂

Reactions

As originally determined by Staudinger,^[7] oxalyl chloride reacts with water giving off gaseous products only: hydrogen chloride (HCl), carbon dioxide (CO₂), and carbon monoxide (CO).^[9]

(COCl)₂ + H₂O → 2 HCl + CO₂ + CO

Other acyl chlorides hydrolyze with formation of hydrogen chloride and the original carboxylic acid.

Applications in organic synthesis

Oxidation of alcohols

Addition of a primary or secondary alcohol to a solution of oxalyl chloride in DMSO, followed by quenching with an organic base such as triethylamine converts alcohols to the corresponding aldehydes and ketones via the process known as the Swern oxidation.^[10]^[11]^[12]

Synthesis of acyl chlorides

Oxalyl chloride is mainly used together with a N,N-dimethylformamide catalyst in organic synthesis for the preparation of acyl chlorides from the corresponding carboxylic acids.^{[citation needed]} Like thionyl chloride, the reagent degrades into volatile side products in this application, which simplifies workup. One of the minor byproducts from the N,N-dimethylformamide catalyzed reaction, dimethylcarbamoyl chloride, is a potent carcinogen, stemming from the N,N-dimethylformamide decomposition.^[13]^[14] Relative to thionyl chloride, oxalyl chloride tends to be a milder, more selective reagent. It is also more expensive than thionyl chloride so it tends to be used on a smaller scale.

This reaction involves conversion of N,N-dimethylformamide to the imidoyl chloride derivative (chloromethylene(dimethyl)ammonium ion (CH₃)₂N⁺=CHCl), akin to the first stage in the Vilsmeier–Haack reaction. The imidoyl chloride is the active chlorinating agent.

Formylation of arenes

Oxalyl chloride reacts with aromatic compounds in the presence of aluminium chloride to give the corresponding acyl chloride in a process known as a Friedel-Crafts acylation.^[15]^[16] The resulting acyl chloride can be hydrolysed to form the corresponding carboxylic acid.

Preparation of oxalate diesters

Like other acyl chlorides, oxalyl chloride reacts with alcohols to give esters:

2 R−CH₂−OH + Cl−C(=O)−C(=O)Cl → R−CH₂−O−C(=O)−C(=O)−O−CH₂−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.^{[citation needed]}

A similar reaction occurs with amines to give substituted oxalamides:^[17]

2 R−NH₂ + ClC(=O)−C(=O)Cl → R−C(=O)−C(=O)−R + 2 HCl

Other

Oxalyl chloride was reportedly used in the first synthesis of dioxane tetraketone (C₄O₆), an oxide of carbon.^[18]

Precautions

In March 2000, a Malaysia Airlines Airbus A330-300 was damaged beyond repair after a cargo of prohibited oxalyl chloride (falsely declared as hydroxyquinoline) leaked into the cargo bay.^[19] It is toxic by inhalation, although it is over an order of magnitude less acutely toxic than the related compound phosgene.^[20]

References

^ ^a ^b Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 797. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.
^ Oxalyl chloride: odor
^ ^a ^b ^c ^d ^e Oxalyl chloride MSDS
^ Salmon, R. (2001). "Oxalyl Chloride". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.ro015. ISBN 0471936235.
^ Fauconnier, Adrien (1892). "Action du perchlorure de phosphore sur l'oxalate d'éthyle" [The action of phosphorus pentachloride on diethyl oxalate]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 114: 122–123.
^ DE patent 2840435, Vogel, A.; Steffan, G.; Mannes, K.; Trescher, V., "Process for the preparation of oxalyl chloride", issued 1980-03-27, assigned to Bayer
^ ^a ^b Staudinger, H. (1908). "Oxalylchlorid". Berichte der Deutschen Chemischen Gesellschaft. 41 (3): 3558–3566. doi:10.1002/cber.19080410335.
^ Pfoertner, Karl-Heinz (2000). "Photochemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_573. ISBN 3527306730.
^ Hansen, Steffen V. F.; Ulven, Trond (2015). "Oxalyl Chloride as a Practical Carbon Monoxide Source for Carbonylation Reactions". Organic Letters. 17 (11): 2832–2835. doi:10.1021/acs.orglett.5b01252. PMID 26000869.
^ Dondoni, A.; Perrone, D. (2004). "Synthesis of 1,1-Dimethyl Ethyl-(S)-4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate by Oxidation of the Alcohol". Organic Syntheses; Collected Volumes, vol. 10, p. 320.
^ Bishop, R. (1998). "9-Thiabicyclo[3.3.1]nonane-2,6-dione". Organic Syntheses; Collected Volumes, vol. 9, p. 692.
^ Leopold, E. J. (1990). "Selective hydroboration of a 1,3,7-triene: Homogeraniol". Organic Syntheses; Collected Volumes, vol. 7, p. 258.
^ Clayden, Jonathan (2005). Organic chemistry (Reprinted(with corrections) ed.). Oxford [u.a.]: Oxford Univ. Press. pp. 296. ISBN 978-0-19-850346-0.
^ Levin, D. (1997). "Potential Toxicological Concerns Associated with Carboxylic Acid Chlorination and Other Reactions". Organic Process Research & Development. 1 (2). American Chemical Society: 182. doi:10.1021/op970206t.
^ Neubert, M. E.; Fishel, D. L. (1983). "Preparation of 4-Alkyl- and 4-Halobenzoyl Chlorides: 4-Pentylbenzoyl Chloride". Organic Syntheses. 61: 8; Collected Volumes, vol. 7, p. 420.
^ Sokol, P. E. (1964). "Mesitoic Acid". Organic Syntheses. 44: 69; Collected Volumes, vol. 5, p. 706.
^ Zou, You-Quan; Zhou, Quan-Quan; Diskin-Posner, Yael; Ben-David, Yehoshoa; Milstein, David (2020). "Synthesis of oxalamides by acceptorless dehydrogenative coupling of ethylene glycol and amines and the reverse hydrogenation catalyzed by ruthenium". Chemical Science. 11 (27): 7188–7193. doi:10.1039/D0SC02065F. PMC 8159388. PMID 34123004.
^ Strazzolini, P.; Gambi, A.; Giumanini, A. G.; Vancik, H. (1998). "The reaction between ethanedioyl (oxalyl) dihalides and Ag₂C₂O₄: a route to Staudinger's elusive ethanedioic (oxalic) acid anhydride". Journal of the Chemical Society, Perkin Transactions 1. 1998 (16): 2553–2558. doi:10.1039/a803430c.
^ "Firm told to pay $65 mln for ruining plane". Reuters. 2007-12-06. Retrieved 2007-12-06.
^ Barbee, S.J.; Stone, J.J.; Hilaski, R.J. (January 1995). "Acute Inhalation Toxicology of Oxalyl Chloride". American Industrial Hygiene Association Journal. 56 (1): 74–76. doi:10.1080/15428119591017358. ISSN 0002-8894. PMID 7872205.

[iupac2013-1] Nomenclature of Organic Chemistry: IUPAC Recommendations and Preferred Names 2013 (Blue Book). Cambridge: The Royal Society of Chemistry. 2014. p. 797. doi:10.1039/9781849733069-FP001. ISBN 978-0-85404-182-4.

[2] Oxalyl chloride: odor

[COClCOCl-3] Oxalyl chloride MSDS

[eEROS-4] Salmon, R. (2001). "Oxalyl Chloride". Encyclopedia of Reagents for Organic Synthesis. New York: John Wiley & Sons. doi:10.1002/047084289X.ro015. ISBN 0471936235.

[5] Fauconnier, Adrien (1892). "Action du perchlorure de phosphore sur l'oxalate d'éthyle" [The action of phosphorus pentachloride on diethyl oxalate]. Comptes rendus hebdomadaires des séances de l'Académie des Sciences (in French). 114: 122–123.

[6] DE patent 2840435, Vogel, A.; Steffan, G.; Mannes, K.; Trescher, V., "Process for the preparation of oxalyl chloride", issued 1980-03-27, assigned to Bayer

[Staudinger-7] Staudinger, H. (1908). "Oxalylchlorid". Berichte der Deutschen Chemischen Gesellschaft. 41 (3): 3558–3566. doi:10.1002/cber.19080410335.

[8] Pfoertner, Karl-Heinz (2000). "Photochemistry". Ullmann's Encyclopedia of Industrial Chemistry. Weinheim: Wiley-VCH. doi:10.1002/14356007.a19_573. ISBN 3527306730.

[9] Hansen, Steffen V. F.; Ulven, Trond (2015). "Oxalyl Chloride as a Practical Carbon Monoxide Source for Carbonylation Reactions". Organic Letters. 17 (11): 2832–2835. doi:10.1021/acs.orglett.5b01252. PMID 26000869.

[10] Dondoni, A.; Perrone, D. (2004). "Synthesis of 1,1-Dimethyl Ethyl-(S)-4-formyl-2,2-dimethyl-3-oxazolidinecarboxylate by Oxidation of the Alcohol". Organic Syntheses; Collected Volumes, vol. 10, p. 320.

[11] Bishop, R. (1998). "9-Thiabicyclo[3.3.1]nonane-2,6-dione". Organic Syntheses; Collected Volumes, vol. 9, p. 692.

[12] Leopold, E. J. (1990). "Selective hydroboration of a 1,3,7-triene: Homogeraniol". Organic Syntheses; Collected Volumes, vol. 7, p. 258.

[13] Clayden, Jonathan (2005). Organic chemistry (Reprinted(with corrections) ed.). Oxford [u.a.]: Oxford Univ. Press. pp. 296. ISBN 978-0-19-850346-0.

[14] Levin, D. (1997). "Potential Toxicological Concerns Associated with Carboxylic Acid Chlorination and Other Reactions". Organic Process Research & Development. 1 (2). American Chemical Society: 182. doi:10.1021/op970206t.

[15] Neubert, M. E.; Fishel, D. L. (1983). "Preparation of 4-Alkyl- and 4-Halobenzoyl Chlorides: 4-Pentylbenzoyl Chloride". Organic Syntheses. 61: 8; Collected Volumes, vol. 7, p. 420.

[16] Sokol, P. E. (1964). "Mesitoic Acid". Organic Syntheses. 44: 69; Collected Volumes, vol. 5, p. 706.

[17] Zou, You-Quan; Zhou, Quan-Quan; Diskin-Posner, Yael; Ben-David, Yehoshoa; Milstein, David (2020). "Synthesis of oxalamides by acceptorless dehydrogenative coupling of ethylene glycol and amines and the reverse hydrogenation catalyzed by ruthenium". Chemical Science. 11 (27): 7188–7193. doi:10.1039/D0SC02065F. PMC 8159388. PMID 34123004.

[18] Strazzolini, P.; Gambi, A.; Giumanini, A. G.; Vancik, H. (1998). "The reaction between ethanedioyl (oxalyl) dihalides and Ag₂C₂O₄: a route to Staudinger's elusive ethanedioic (oxalic) acid anhydride". Journal of the Chemical Society, Perkin Transactions 1. 1998 (16): 2553–2558. doi:10.1039/a803430c.

[19] "Firm told to pay $65 mln for ruining plane". Reuters. 2007-12-06. Retrieved 2007-12-06.

[20] Barbee, S.J.; Stone, J.J.; Hilaski, R.J. (January 1995). "Acute Inhalation Toxicology of Oxalyl Chloride". American Industrial Hygiene Association Journal. 56 (1): 74–76. doi:10.1080/15428119591017358. ISSN 0002-8894. PMID 7872205.

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