Dimethyl ether

Dimethyl ether

| Section8 = }} Dimethyl ether is the organic compound with the formula CH3OCH3. The simplest ether, it is a colourless gas that is a useful precursor to other organic compounds and an aerosol propellant. Dimethyl ether is also promising as a clean-burning hydrocarbon fuel.

Production

Dimethyl ether is produced by the dehydration of methanol:
2 CH3OH → CH3OCH3 + H2O
Approximately 50,000 tons were produced in 1985 in Western Europe alone. In principle, it could also be manufactured by partial hydrogenation of carbon monoxide, which in turn can be obtained from many sources of hydrocarbons, including biomass.

Applications

Dimethyl ether has two primary applications: as a propellent in aerosol cannisters, and as a precursor to dimethyl sulfate. As an aerosol propellent, dimethyl ether is useful as a somewhat polar solvent.

Feedstock

Several thousand tons of dimethyl ether are consumed annually for the production of the methylating agent, dimethyl sulfate, via the reaction with sulfur trioxide:
CH3OCH3 + SO3 → (CH3O)2SO2

This compound is also converted to acetic acid using technology related to the Monsanto acetic acid process:

(CH3)2O + 2 CO + H2O → 2 CH3CO2H

Laboratory reagent and solvent

Dimethyl ether is a low-temperature solvent and extraction agent that is used as a solvent in specialised laboratory procedures. Its usefulness is limited by its low boiling point (−23 °C), but the same property facilitates its removal from reaction mixtures. Dimethyl ether is the precursor to the useful alkylating agent, trimethyloxonium tetrafluoroborate.

Fuel

DME is a promising fuel in diesel engines, petrol engines (30% DME / 70% LPG), and gas turbines owing to its high cetane number, which is greater than 55 compared to diesel, which is 40–53. Only moderate modification are needed to convert a diesel engine to burn DME. The simplicity of this short carbon chain compound leads during combustion to very low emissions of particulate matter, NOx, CO. For these reasons as well as being sulfur-free, dimethyl ether meets even the most stringent emission regulations in Europe (EURO5), U.S. (U.S. 2010), and Japan (2009 Japan). DME is being developed as a synthetic biofuel (BioDME), which can be manufactured from lignocellulosic biomass. Currently the EU is considering BioDME in its potential biofuel mix in 2030, the Volvo Group is the coordinator for the European project BioDME. and Mobil is using it in their methanol to gasoline process. The image below illustrates some of processes from various raw materials to DME.

Treating warts

A mixture of dimethyl ether and propane is used in an over-the-counter device to treat warts, by freezing them.

Safety

Unlike other alkyl ethers, it resists autoxidation. Dimethyl ether is also relatively non-toxic, although it is highly flammable.

References

External links

Search another word or see Dimethyl Etheron Dictionary | Thesaurus |Spanish
Copyright © 2014 Dictionary.com, LLC. All rights reserved.
  • Please Login or Sign Up to use the Recent Searches feature