| IUPAC name
| Systematic IUPAC name
| Other names
Oxalic acid chloride
Oxalic acid dichloride
|Molar mass||126.93 g/mol|
|Melting point||−16 °C (3 °F; 257 K)|
|Boiling point||63–64 °C (145–147 °F; 336–337 K)|
|Solubility||Reacts with alcohols, amines, carboxylic acids|
|Safety data sheet||Sigma-Aldrich|
| Oxalic acid|
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
Oxalyl chloride is the acyl chloride of oxalic acid. It is used as a chlorinating agent, similar to thionyl chloride. Like other acyl chlorides, it is also used for producing derivatives of the parent acid such as esters. Aromatic esters of oxalic acid are used in glowsticks.
Oxalyl chloride behaves similarly to other acyl chlorides in that reacting with alcohols produces the corresponding ester. Unusually, however, reaction with water does not yield the parent acid, but instead results in decomposition to carbon dioxide, carbon monoxide, and hydrogen chloride.
Other carboxylic acids can be converted to the corresponding acyl chloride by treatment with oxalyl chloride in the presence of a catalytic amount of a nitrogen base such as dimethylformamide, triethylamine, or pyridine. The byproducts produced by this reaction are carbon dioxide and carbon monoxide.
Oxalyl chloride is available from chemical suppliers but due to its hazards it is often hard to get for amateurs.
- Make Bis(2,4,6-trichlorophenyl)oxalate for glowsticks
Oxalyl chloride is very toxic and presents a severe inhalational hazard. It should only be used with very good ventilation.