Dimethoxyethane
Encyclopedia
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 miscible with 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 reaction
s, hydride reductions, and palladium-catalyzed reactions like Suzuki reaction
s and Stille coupling. Dimethoxyethane is also a good solvent for oligo- and polysaccharides.
The lowest energy form of dimethoxyethane in the gas phase is the gauche, rather than the anti conformer.
chemical (e.g. propylene carbonate
), dimethoxyethane is used as the low-viscosity
component of the solvent for electrolyte
s of lithium batteries
.
Ether
Ethers are a class of organic compounds that contain an ether group — an oxygen atom connected to two alkyl or aryl groups — of general formula R–O–R'. A typical example is the solvent and anesthetic diethyl ether, commonly referred to simply as "ether"...
that is used as a solvent
Solvent
A solvent is a liquid, solid, or gas that dissolves another solid, liquid, or gaseous solute, resulting in a solution that is soluble in a certain volume of solvent at a specified temperature...
. Dimethoxyethane is miscible with water.
Dimethoxyethane is often used as a higher boiling alternative to diethyl ether
Diethyl ether
Diethyl ether, also known as ethyl ether, simply ether, or ethoxyethane, is an organic compound in the ether class with the formula . It is a colorless, highly volatile flammable liquid with a characteristic odor...
and THF
Tetrahydrofuran
Tetrahydrofuran is a colorless, water-miscible organic liquid with low viscosity at standard temperature and pressure. This heterocyclic compound has the chemical formula 4O. As one of the most polar ethers with a wide liquid range, it is a useful solvent. Its main use, however, is as a precursor...
. Dimethoxyethane forms chelate
Chelation
Chelation is the formation or presence of two or more separate coordinate bonds between apolydentate ligand and a single central atom....
complexes with cations and acts as a bidentate ligand
Ligand
In coordination chemistry, a ligand is an ion or molecule that binds to a central metal atom to form a coordination complex. The bonding between metal and ligand generally involves formal donation of one or more of the ligand's electron pairs. The nature of metal-ligand bonding can range from...
. It is therefore often used in organometallic chemistry
Organometallic chemistry
Organometallic chemistry is the study of chemical compounds containing bonds between carbon and a metal. Since many compounds without such bonds are chemically similar, an alternative may be compounds containing metal-element bonds of a largely covalent character...
like Grignard reaction
Grignard reaction
The Grignard reaction is an organometallic chemical reaction in which alkyl- or aryl-magnesium halides add to a carbonyl group in an aldehyde or ketone. This reaction is an important tool for the formation of carbon–carbon bonds...
s, hydride reductions, and palladium-catalyzed reactions like Suzuki reaction
Suzuki reaction
The Suzuki reaction is the organic reaction of an aryl- or vinyl-boronic acid with an aryl- or vinyl-halide catalyzed by a palladium complex. It is widely used to synthesize poly-olefins, styrenes, and substituted biphenyls, and has been extended to incorporate alkyl bromides...
s and Stille coupling. Dimethoxyethane is also a good solvent for oligo- and polysaccharides.
The lowest energy form of dimethoxyethane in the gas phase is the gauche, rather than the anti conformer.
Production
Monoglyme may be manufactured by a number of methods:- via the Williamson ether synthesisWilliamson ether synthesisThe Williamson ether synthesis is an organic reaction, forming an ether from an organohalide and an alcohol. This reaction was developed by Alexander Williamson in 1850. Typically it involves the reaction of an alkoxide ion with a primary alkyl halide via an SN2 reaction...
— reacting the sodium salt of 2-methoxyethanol2-Methoxyethanol2-Methoxyethanol, or methyl cellosolve, is an organic compound that is used mainly as a solvent. It is a clear, colorless liquid with an ether-like odor. It is in a class of solvents known as glycol ethers which are notable for their ability to dissolve a variety of different types of chemical...
(previously prepared by reaction with sodiumSodiumSodium is a chemical element with the symbol Na and atomic number 11. It is a soft, silvery-white, highly reactive metal and is a member of the alkali metals; its only stable isotope is 23Na. It is an abundant element that exists in numerous minerals, most commonly as sodium chloride...
) with chloromethaneChloromethaneChloromethane, also called methyl chloride, R-40 or HCC 40, is a chemical compound of the group of organic compounds called haloalkanes. It was once widely used as a refrigerant. It is a colorless extremely flammable gas with a minorly sweet odor, which is, however, detected at possibly toxic levels...
:
- 2 CH3OCH2CH2OH + 2 Na → 2 CH3OCH2CH2ONa + H2↑
- CH3OCH2CH2ONa + CH3Cl → CH3OCH2CH2OCH3 + NaCl
- via the alkylationAlkylationAlkylation is the transfer of an alkyl group from one molecule to another. The alkyl group may be transferred as an alkyl carbocation, a free radical, a carbanion or a carbene . Alkylating agents are widely used in chemistry because the alkyl group is probably the most common group encountered in...
of 2-methoxyethanol with dimethyl sulfateDimethyl sulfateDimethyl sulfate is a chemical compound with formula 2SO2. As the diester of methanol and sulfuric acid, its formula is often written as 2SO4 or even Me2SO4, where CH3 or Me is methyl... - by the cleavage of ethylene oxideEthylene oxideEthylene oxide, also called oxirane, is the organic compound with the formula . It is a cyclic ether. This means that it is composed of two alkyl groups attached to an oxygen atom in a cyclic shape . This colorless flammable gas with a faintly sweet odor is the simplest epoxide, a three-membered...
in presence of dimethyl etherDimethyl etherDimethyl ether , also known as methoxymethane, is the organic compound with the formula . The simplest ether, it is a colourless gas that is a useful precursor to other organic compounds and an aerosol propellant. When combusted, DME produces minimal soot and CO, though HC and NOx formation is...
. This reaction is catalyzed by Lewis acids (e.g. boron trifluorideBoron trifluorideBoron trifluoride is the chemical compound with the formula BF3. This pungent colourless toxic gas forms white fumes in moist air. It is a useful Lewis acid and a versatile building block for other boron compounds.-Structure and bonding:...
or its complex with dimethyl ether). This route is not particularly selective and produces diglyme, triglyme, tetraglyme, and other glymes as a by-products. The reaction mixture is separated by distillationDistillationDistillation is a method of separating mixtures based on differences in volatilities of components in a boiling liquid mixture. Distillation is a unit operation, or a physical separation process, and not a chemical reaction....
:
- CH3OCH3 + CH2CH2O → CH3OCH2CH2OCH3
- via the alkylation
Uses
Together with a high-permittivityPermittivity
In electromagnetism, absolute permittivity is the measure of the resistance that is encountered when forming an electric field in a medium. In other words, permittivity is a measure of how an electric field affects, and is affected by, a dielectric medium. The permittivity of a medium describes how...
chemical (e.g. propylene carbonate
Propylene carbonate
Propylene carbonate is an organic compound, a cyclic carbonate of propylene glycol. This colorless and odorless liquid is useful as a polar, aprotic solvent...
), dimethoxyethane is used as the low-viscosity
Viscosity
Viscosity is a measure of the resistance of a fluid which is being deformed by either shear or tensile stress. In everyday terms , viscosity is "thickness" or "internal friction". Thus, water is "thin", having a lower viscosity, while honey is "thick", having a higher viscosity...
component of the solvent for electrolyte
Electrolyte
In chemistry, an electrolyte is any substance containing free ions that make the substance electrically conductive. The most typical electrolyte is an ionic solution, but molten electrolytes and solid electrolytes are also possible....
s of lithium batteries
Lithium battery
Lithium batteries are disposable batteries that have lithium metal or lithium compounds as an anode. Depending on the design and chemical compounds used, lithium cells can produce voltages from 1.5 V to about 3.7 V, over twice the voltage of an ordinary zinc–carbon battery or alkaline battery...
.