Dimethyl ether (DME) is a multipurpose clean fuel and chemical feedstock that can be produced from a wide variety of of sources and has a number of important applications. About 10,000 tons of DME are manufactured each year for uses in cosmetics and aerosal paint propellants. Its new use as a clean fuel source is gaining attention and research, as it contains no sulfur or nitrogen compounds, has a very low toxicity, and is not corrosive to metals. It can be stored and transported as a liquid at low temperatures

A single-stage, liquid phase synthesis process for DME in a slurry phase reactor system is efficient and facilatates heat removal. The combination of methanol synthesis and methanol dehydration reversible reactions in a single step is thermodynamically more favorable. The liquid phase operation allows for better heat management and higher yields of DME.

The first pictured reaction shows the methanol synthesized from carbon dioxide and it is combined with the second pictured reaction into the last pictured reaction, in which the synthesized methanol is dehydrated to produce DME.

See here for the CiteULike with the reactions and here for another journal article about DME. In addition, the catalytic synthesis of methanol is covered in Ch.10 of Wade and DME itself is discussed in Ch.14.

There are four types of reactions:

Substitution Reactions

The reactions in which an atom or group of atoms in a molecule is replaced or substituted by different atoms or group of atoms are called substitution reaction. For example,

These reactions can be of two types:

Nucleophilic Substitution

In this type of substitution, atom or group of atoms in the molecule is replaced by a nucleophile. These can be either S_N1 (substitution, nucleophilic, unimolecular) or S_N2 (substitution, nucleophilic, bimolecular) type.
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