Dimethyl ether
IUPAC name	methoxymethane
Other names	DME, wood ether dimethyl oxide Demeon, Dymel A
Identifiers
CAS number	115-10-6
RTECS number	PM3780000
SMILES	COC
Properties
Molecular formula	C2H6O CH3OCH3
Molar mass	46.07 g/mol
Appearance	colourless gas with typical smell
Density	1.59, gas (vs air) 668 kg/m3, liquid
Melting point	-138.5°C (134.6 K)/(-217.3°F) 242.37°R Image File history File links The structure of dimethyl ether, drawn in ChemDraw by User:Walkerma in July 2005. ... IUPAC nomenclature is a system of naming chemical compounds and of describing the science of chemistry in general. ... CAS registry numbers are unique numerical identifiers for chemical compounds, polymers, biological sequences, mixtures and alloys. ... RTECS, also known as Registry of Toxic Effects of Chemical Substances, is a database of toxicity information compiled from the open scientific literature that is available for charge. ... The simplified molecular input line entry specification or SMILES is a specification for unambiguously describing the structure of chemical molecules using short ASCII strings. ... A chemical formula is a concise way of expressing information about the atoms that constitute a particular chemical compound. ... Molar mass is the mass of one mole of a chemical element or chemical compound. ... For other uses, see Density (disambiguation). ... The melting point of a crystalline solid is the temperature range at which it changes state from solid to liquid. ...
Boiling point	-23°C (254 K)/(-12.82°F) 446.85°R Italic text This article is about the boiling point of liquids. ...
Solubility in water	328 g/100 mL (20°C)
Structure
Dipole moment	1.30 D (gas)
Hazards
MSDS	External MSDS
MSDS	External MSDS
Main hazards	highly flammable
R-phrases	R12
S-phrases	(S2), S9, S16, S33
Flash point	-41°C/(-41.8°F) 417.87°R
Related Compounds
Related ethers	diethyl ether crown ether polyethylene glycol
Related compounds	methanol
Supplementary data page
Structure and properties	n, εr, etc.
Thermodynamic data	Phase behaviour Solid, liquid, gas
Spectral data	UV, IR, NMR, MS
Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa) Infobox disclaimer and references

Dimethyl ether, also known as methoxymethane, oxybismethane, methyl ether, wood ether, and DME, is a colorless gaseous ether with an ethereal odor. Dimethyl ether gas is water soluble. It has the formula CH₃OCH₃or as its empirical formula C₂H₆O (which it shares with ethanol). Dimethyl ether is used as an aerosol spray propellant, and is used in conjunction with propane to give a thermic expansion that lowers temperature to -60°C. This property is usefull in cryogenic freezing of common warts found on the human body. Dimethyl ether is also a clean-burning alternative to liquified petroleum gas, liquified natural gas, diesel and gasoline. It can be made from natural gas, coal, or biomass. Solubility is a chemical property referring to the ability for a given substance, the solute, to dissolve in a solvent. ... Impact from a water drop causes an upward rebound jet surrounded by circular capillary waves. ... The Earths magnetic field, which is approximately a dipole. ... The debye (symbol: D) is a non-SI and non-CGS unit of electrical dipole moment. ... An example MSDS in a US format provides guidance for handling a hazardous substance and information on its composition and properties. ... J. Chem. ... This page meets Wikipedias criteria for speedy deletion. ... The examples and perspective in this article or section may not represent a worldwide view. ... R-phrases are defined in Annex III of European Union Directive 67/548/EEC: Nature of special risks attributed to dangerous substances and preparations. ... S-phrases are defined in Annex IV of European Union Directive 67/548/EEC: Safety advice concerning dangerous substances and preparations. ... For other uses, see Flash point (disambiguation). ... This article is about a general class of chemical compounds. ... This article is about the chemical compound. ... Crown ethers are heterocyclic chemical compounds that, in their simplest form, are cyclic oligomers of ethylene oxide. ... Polyethylene glycol (PEG) and polyethylene oxide (PEO) are polymers composed of repeating subunits of identical structure, called monomers, and are the most commercially important polyethers. ... Methanol, also known as methyl alcohol, carbinol, wood alcohol, wood naptha or wood spirits, is a chemical compound with chemical formula CH3OH. It is the simplest alcohol, and is a light, volatile, colourless, flammable, poisonous liquid with a distinctive odor that is somewhat milder and sweeter than ethanol (ethyl alcohol). ... J. Chem. ... J. Chem. ... The refractive index (or index of refraction) of a medium is a measure for how much the speed of light (or other waves such as sound waves) is reduced inside the medium. ... The relative dielectric constant of a material under given conditions is a measure of the extent to which it concentrates electrostatic lines of flux. ... J. Chem. ... J. Chem. ... 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Coal Example chemical structure of coal Coal (pronounced ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... For the use of the term in ecology, see Biomass (ecology). ...

Production

Conventional DME production uses the methanol dehydration method.^[1] For mass production of DME as a fuel other methods are being considered, the main one being DME synthesis from hydrogen and CO gas, also known as syngas.^[2] It has been suggested that Town gas be merged into this article or section. ...

DME can be produced from methanol by combining two methanol molecules to produce a DME molecule and a water molecule.^[3] This is a reversible reaction.^[3] This can be shown in the following equation:

methanol → dimethyl ether + water

2CH₃OH → CH₃OCH₃ + H₂O

There are various companies developing this method of DME production, the most active one being JFE Holding in Japan.^{[citation needed]} The DME-synthesis method has a better overall efficiency because with methanol dehydration,^{[citation needed]} the methanol is firstly produced from a base source such as LPG, NG or coal via synthesis and then this is converted into DME.^{[citation needed]} This method attempts to cut out the intermediate methanol production and produce DME from LPG, NG, coal or even biomass in one process.^{[citation needed]}

DME production from solid raw materials such as biomass and coal requires more processes than DME production from gases such as NG and LPG. This is because the solid materials need go through the gasification process to produce the syngas required for the DME-synthesis. To allow for more efficient gasification the biomass and coal have various preparation processes; such as chipping of the biomass or producing slurry of the coal. To ensure that the DME produced is clean there are various gas scrubbing, cleaning and purification processes. DME production from methane can simply use a methane reforming method to produce the syngas for the DME synthesis. For the use of the term in ecology, see Biomass (ecology). ... Coal Example chemical structure of coal Coal (pronounced ) is a fossil fuel formed in swamp ecosystems where plant remains were saved by water and mud from oxidization and biodegradation. ... For other uses, see Ng (disambiguation). ... LPG might be an initialism or abbreviation for: Liquified petroleum gas Laboratoire de Planetologie, Grenoble, France Literary Press Group of Canada Landwirtschaftliche Produktionsgenossenschaft (German, obsolete/historical) Long period grating This page concerning a three-letter acronym or abbreviation is a disambiguation page — a navigational aid which lists other pages that... For the water carbonator, see Gasogene. ... It has been suggested that Town gas be merged into this article or section. ... It has been suggested that this article or section be merged into Steam reforming. ...

The image below shows a simple representation of the various processes from raw materials to DME.

Image File history File links Size of this preview: 800 × 366 pixelsFull resolution‎ (917 × 420 pixels, file size: 42 KB, MIME type: image/jpeg) A simple diagram showing the basic processes and heat flows from raw materials to dimethyl ether I, the copyright holder of this work, hereby release it...

Applications

DME is used as:^[4]

• A refrigerant
• A (co-)blowing agent for foam
• A propellant for aerosol products
• A solvent
• An extraction agent
• A chemical reaction medium
• A fuel for welding cutting and brazing
• A multi-purpose fuel

As a fuel

DME can be used as a fuel in diesel engines,^[5] petrol engines (30% DME / 70% LPG) and gas turbines. It works particularly well in diesel engines due to its high cetane number, which is greater than 55 compared to diesel which is 38-53.^[6] The diesel engine is a type of internal combustion engine; more specifically, a compression ignition engine, in which the fuel is ignited by the high temperature of a compressed gas, rather than a separate source of energy (such as a spark plug). ... A Petrol engine or Gasoline engine is an internal combustion engine with spark-ignition designed to run on petrol (gasoline) and similar volatile fuels. ... The worlds first commercial, oil-free gas turbine is manufactured by Capstone. ... Cetane number or CN is to diesel fuel what octane rating is to gasoline. ...

Currently the EU is considering DME in its potential biofuel mix in 2030.^[7]

Solvent

Like ammonia (NH₃), dimethyl ether can be condensed (liquified) and used as a solvent. Clearly there are limitation on the maximum temperature (e.g. the boiling/reflux temperature i.e. -23°C) which the solvent can be used. One advantage of using dimethyl ether as a solvent is that is readily removed by evaporation, especially from a product which has a relatively low boiling point. For other uses, see Ammonia (disambiguation). ... In the physical sciences, a phase is a set of states of a macroscopic physical system that have relatively uniform chemical composition and physical properties (i. ... Boiling, a type of phase transition, is the rapid vaporization of a liquid, which typically occurs when a liquid is heated to its boiling point, the temperature at which the vapor pressure of the liquid is equal to the pressure exerted on the liquid by the surrounding atmospheric pressure. ... Diagram of typical reflux apparatus. ...

References

1. ^ demeon.com, production process
2. ^ JFE-holdings.co.jp, dme
3. ^ ^{a b} gov.br, dehydration catalyst
4. ^ demeon.com, Akzo Nobel DME
5. ^ nycomb.se, Nycomb Chemicals company
6. ^ topsoe.com, Haldor Topsoe Chemicals Company
7. ^ refuel.eu, EU Refuel biofuel project

External links

• Facts about DME from the International DME Association
• [1] Material Safety Data Sheet
• dimethyl ether 3D view and pdb-file