Description
Dimethyl oxalate is a chemical compound with formula (CH
3)
2(COO)
2. It is the dimethyl ester of oxalic acid.
General Description
Dimethyl oxalate (DMO), (CH3OCO)2 is an industrial chemical intermediate with versatile properties. DMO is used as a solvent and extraction agent to produce ethylene glycol, ethanol, oxalic acid, oxamide, dyes, and medicines. Besides, dimethyl carbonate (DMC), (CH3O)2CO is attracting lots of interest because of its excellent solubility, biodegradability and low toxicity. DMC could be used as a green solvent, as electrolytes in lithium batteries, as a potential fuel additive and for polycarbonate synthesis[1].
Chemical Properties
colourless crystals
Chemical Properties
The empirical formula of dimethyl oxalate is C4H6O4. It
exists as a liquid between its pour point (52°C) and boiling
point (163.4°C). It is soluble in ethanol and ether and slightly
soluble in water.
Uses
Dimethyl oxalate is used as an alternate fuel in the direct oxidation fuel cell. It is involved in the catalytic hydrogenation using Cu/SiO22ub> to prepare ethylene glycol. It is also used in the selective gas-phase hydrogenation catalyzed by Ag/SiO2 to get the corresponding alcohol.
Definition
ChEBI: Methyl oxalate is a diester, a methyl ester and a member of dicarboxylic acids and O-substituted derivatives. It is functionally related to an oxalic acid.
Synthesis Reference(s)
The Journal of Organic Chemistry, 24, p. 261, 1959
DOI: 10.1021/jo01084a633
General Description
Dimethyl oxalate undergoes Cu/SiO
2 catalyzed hydrogenation to yield ethylene glycol. It undergoes selective gas-phase hydrogenation catalyzed by Ag/SiO
2 to yield corresponding alcohol.
Synthesis
Process for dimethyl oxalate synthesis via carbon monoxide methyl nitrite route:
1. NO generation from sodium nitrite and dilute nitric acid.
2. Esterification: NO, O, and methanol react in an esterifier to form methyl nitrite.
3. Carbonylation: Methyl nitrite reacts with CO in a carbonylation reactor to form dimethyl oxalate.
4. Product separation: Dimethyl oxalate is absorbed by methanol scrubbing and then purified by distillation.
Purification Methods
Crystallise the ester repeatedly from EtOH. De-gas it under nitrogen at high vacuum and distil it. [Beilstein 2 IV 1847.]
References
[1] Chunzheng Wang. “Emerging Co-Synthesis of Dimethyl Oxalate and Dimethyl Carbonate Using Pd/Silicalite-1 Catalyst with Synergistic Interactions of Pd and Silanols.” SSRN Electronic Journal 71 1 (2023).
