Ether

For ether, in physics and philosophy, see Aether.

In addition to the generic meaning, the term "ether" also commonly refers to the specific compound diethyl ether, CH₃CH₂OCH₂CH₃, also known as ethoxyethane. Chemist Raymundus Lullis, discovered the compound in 1275. Its was first synthesized by Valerius Cordus in 1540. Crawford Williamson Long, M.D., was the first surgeon to use it as an anesthetic agent, on March 30, 1842. Its first use is normally associated with the Etherdome in Boston.

In chemistry, an ether is functional group that may result from the condensation of alcohols.

Table of contents

1 Reactions

1.1 Synthesis

2 Physical properties
3 Nomenclature

Reactions

Synthesis

2alcohol → ether
- This direct reaction is not suitable in most synthetic pathways. There exist several milder methods to produce ethers.
alkoxide + alkyl halide → ether
- This is called Williamson ether synthesis. It involves treatment of a parent alcohol (R-OH) with a strong base to form the alkoxide ion (R-O-) followed by addition of an appropriate aliphatic compound bearing a suitable leaving group (R-L). Suitable leaving groups (L) include Iodine, Bromine or Sulfonate esters.
alkene + alcohol + acid catalyst → ether

Physical properties

Like esters, ethers are limited in their ability to form hydrogen bonds. They tend to be more hydrophobic than other, analogous condensation products (such as esters or amides). They are resistant to hydrolysis.

Ethers which have a CH group next to the oxygen form peroxides which are highly explosive. Due to this and the low ignition point of diethyl ether, diethyl ether is one of the risk factors in laboratories.

Despite their comparably attenuated reactivity, ethers can act as Lewis acids (see Acid-base reaction theories). For instance, diethyl ether forms a complex with boron compounds, such as boron trifluoride etherate, F₃B:O(CH₂CH₃)₂

Nomenclature

Ethers can be named in two ways according to the IUPAC naming system. The first, used for simple ethers, simply lists the two groups attached to the ether in alphabetical order followed by the word "ether". Thus CH₃-CH₂-O-CH₃ is ethyl methyl ether. When the ether is part of a more complex molecule, it is named as an alkoxy substituent, so -OCH₃ would be considered a "methoxy-" group.