Description
1,2-Dimethoxyethane (DME) is a liquid ether used as an aprotic solvent. It is also known as glyme, monoglyme, dimethyl glycol, ethylene glycol, dimethyl ether, dimethyl cellosolve, and DME. It has the special ability to form chelates thanks to the high flexibility of its chains. Moreover, DME is the molecular model system for the poly(oxyethylene) chain. It is commonly used as a solvent in batteries and in organometallic reaction chemistry since it has higher boiling than diethyl ether and THF[1].
Chemical Properties
Ethylene glycol dimethyl ether, also called 1,2-Dimethoxyethane, is a colorless liquid with a strong smell similar to ether. It is stable and does not easily react. It can dissolve different resins and cellulose, and can be mixed with water and various organic solvents like alcohols, ketones, and esters in any amount. Its solubility can be changed by diluting it with water or specific solvents.
Uses
1,2-Dimethoxyethane is widely used as a solvent for electrolyte of lithium batteries, polysilicones, oligo- and polysaccharides. It plays an important role in Grignard reactions, Suzuki reactions and Stille couplings in organometallic chemistry and in pharmaceutical synthesis. It is a higher boiling point solvent and is used as an alternative to diethyl ether and tetrahydrofuran. It is used for the etching of synthetic polymers like polytetrafluoroethylene and other fluoropolymers with alkali metal dispersions.
Definition
ChEBI: 1,2-dimethoxyethane is a diether that is the 1,2-dimethyl ether of ethane-1,2-diol. It has a role as a non-polar solvent. It is functionally related to an ethylene glycol.
Application
Monoglyme serves as an electrolyte solution component for lithium batteries. It is also frequently utilized as a solvent in organometallic reactions, particularly those involving organolithium compounds. Additionally, it can act as a ligand in certain chemical reactions.
General Description
A liquid with a sharp odor. Less dense than water. Flash point 34°F. Mildly toxic by ingestion and inhalation. Severely irritates skin and eyes. Vapors heavier than air. Used to make other chemicals.
Air & Water Reactions
Highly flammable. Slightly soluble in water.
Reactivity Profile
When the solvent, 1,2-Dimethoxyethane, was poured into a funnel previously used to introduce the lithium aluminum hydride, a fire ignited the funnel, [MCA Case History 1182(1966)].
Hazard
Moderate fire risk.
Health Hazard
If ingested causes nausea, vomiting, cramps, weakness, coma.
Fire Hazard
Behavior in Fire: Containers may explode in fires.
Safety Profile
An experimental
teratogen. Other experimental reproductive
effects. Readdy forms an explosive peroxide.
A very dangerous fire hazard when exposed
to heat, flame, or oxidzers. Mixture with
lithium tetrahydroaluminate may ignite orexplode if heated. When heated to
decomposition it emits acrid smoke and
fumes. See also GLYCOL ETHERS.
Synthesis
1,2-Dimethoxyethane is derived from the reaction of ethylene glycol monomethyl ether with sodium metal and methyl chloride. The ethylene glycol monomethyl ether and the metal sodium were refluxed together until the metal sodium was completely reacted, the temperature was lowered to 45° C., and methyl chloride was introduced. After the reaction is completed, fractional distillation is performed to collect fractions at 84-85.5°C to obtain 1,2-Dimethoxyethane.
Purification Methods
Traces of water and acidic materials have been removed from it by refluxing with Na, K or CaH2, decanting and distilling from Na, K, CaH2 or LiAlH4. The reaction has been speeded up by using vigorous high-speed stirring with molten potassium. For virtually complete elimination of water, 1,2-dimethoxyethane has been dried with Na-K alloy until a characteristic blue colour is formed in the solvent at Dry-ice/cellosolve temperatures: the solvent is kept with the alloy until distilled for use [Ward J Am Chem Soc 83 1296 1961]. Alternatively, glyme, refluxed with benzophenone and Na-K, is dry enough if, on distillation, it gives a blue colour of the ketyl immediately on addition to benzophenone and sodium [Ayscough & Wilson J Chem Soc 5412 1963]. It has also been purified by distillation under N2 from sodium benzophenone ketyl (see above). [Beilstein 1 IV 2376.]
References
[1] Weixing Li . “The microwave spectroscopy study of 1,2-dimethoxyethane.” Journal of Molecular Spectroscopy 337 (2017): Pages 3-8.
