Dimethoxyethane

Dimethoxyethane, also known as glyme, monoglyme, dimethyl glycol, ethylene glycol dimethyl ether, dimethyl cellosolve, and DME, is a clear, colorless, aprotic, and liquid ether that is used as a solvent. Dimethoxyethane is highly soluble in water.

Dimethoxyethane is often used as a higher boiling alternative to diethyl ether and THF. Dimethoxyethane forms chelate complexes with cations and acts as a bidentate ligand. It is therefore often used in organometallic chemistry like Grignard reactions, hydride reductions, and palladium catalyzed reactions like Suzuki reactions and Stille coupling. Dimethoxyethane is also a good solvent for oligo- and polysaccharides.

The lowest energy form of dimethoxy ethane in the gas phase is the gauche, rather than the anti conformer

Production
Monoglyme in commercial quantities can be manufactured by a number of methods:
 * via Williamson ether synthesis, by the reaction of methyl cellosolve sodium salt with chloromethane. Metal alkoxide is produced by interaction of methyl cellosolve with molten sodium. This reaction is accompanied with gaseous hydrogen releasing:
 * 2 CH3OCH2CH2OH + 2 Na → 2 CH3OCH2CH2ONa + H2↑


 * CH3OCH2CH2ONa + CH3Cl → CH3OCH2CH2OCH3 + NaCl


 * by treatment of methyl cellosolve with dimethyl sulfate:
 * by the cleavage of ethylene oxide in presence of dimethyl ether. Reaction is catalyzed with Lewis acids (boron trifluoride (BF3) or its complex with dimethyl ether). This route is not particularly selective and produces di- tri, tetra- and other glymes as a by-products. The reaction mixture is separated by rectification:
 * CH3OCH3 + CH2CH2O → CH3OCH2CH2OCH3

Uses
Together with a high-permittivity chemical (eg. propylene carbonate), dimethoxyethane is used as the low-viscosity component of the solvent for electrolytes of lithium batteries.