Ether

In the Latin language, the word ‘aether’ means ‘to ignite,’ and this is how the word Ether came to be. The majority of ethers are flammable when stored at room temperature and under high pressure. The general formula for ether is R-O-R, R-O-R’, R-O-Ar, or Ar-O-Ar, where R denotes an alkyl group and Ar denotes an aryl group, with R denoting an aryl group.

This is a topic that is commonly encountered in organic chemistry, and it is also a topic that is widely covered in biochemistry, where we find common linkages between carbohydrates and the lignin polymer. Meanwhile, if we look at the structure of ethers, we can see that they are primarily composed of twisted C–O–C linkages.

The General Structure of Ether

Ether is primarily distinguished by the presence of an oxygen atom that is covalently bonded to two alkyl or aryl groups, which are represented here by the letters R and R’. Substituents can be the same or different depending on the situation.

1. CH3 – O – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH (Dimethyl ether)

2. (CH3)2CH – O – CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2CH(CH3)2 (Diisopropyl ether)

3. Cyclic ethers, such as cyclohexane

C6H5 – O – C6H5 is a ether(Diphenyl ether)

The Physical Characteristics of Ethers

1. At room temperature, dimethyl ether and ethyl methyl ether are both gaseous compounds. Other lower homologues are colourless, pleasant smelling, volatile liquids with a characteristic ether smell, as well as other lower homologues.
2. Dipole moment: Because the C-O-C bond angle is not 180°, the dipole moments of the two C-O bonds do not cancel each other out, and as a result, ethers have a relatively low net dipole moment.
3. Boiling point: The boiling points of ether molecules are comparable to those of alkanes, but they are significantly lower when compared to the boiling points of alcohols of comparable molecular mass. Because of the presence of hydrogen bonding in alcohol, this is the case.
4. In terms of water solubility, ethers are similar to alcohols with a similar molecular mass in terms of solubility. Ether molecules are soluble in water, which makes them a good solvent. Due to the fact that, like alcohol, oxygen atoms in ether can also form hydrogen bonds with water molecules, this is the case for this compound. Additionally, the solubility decreases as the number of carbon atoms increases. This is due to the fact that the relative increase in the hydrocarbon content of the molecule reduces the tendency for H-bond formation in the molecule.
5. Polarity: Because of the presence of bulky alkyl groups on both sides of the oxygen atom, ether is less polar than esters, alcohols, and amines. This is due to the fact that the oxygen atom is unable to participate in hydrogen bonding, resulting in ether being less polar than these other compounds. However, ether has a higher polarity than alkenes.
6. Hybridization: In ethers, the oxygen element is sp3 hybridised, resulting in an angle of bonding of 109.50° between the atoms.

Classification of Ethers

Ethers are classified according to their structure. Ethers can be divided into two broad categories, each of which is distinguished by the substituent group that has been attached to the oxygen atom of the ether: symmetrical ethers and asymmetrical ethers.

Symmetrical Ethers

When there are two identical groups attached to the oxygen atom, this is known as symmetrical ethers.

Example:

CH3 – CH2 – O – CH2 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 – CH3 (Diethyl ether)

Asymmetrical Ethers

Asymmetrical ethers are those in which the oxygen atom is attached to two different groups by different chemical bonds.

Example:

CH3 – O – CH2 – CH3 is a three-carbon hexafluoride (Ethyl methyl ether)

Chemical Reactions involving Ether

Ethers are the least reactive of all the functional groups, making them the least reactive of all. Ether bonds are relatively stable in the presence of bases, oxidising agents, and reducing agents, among other things. Ethers, on the other hand, are cleaved as a result of their reaction with acids. The following are the most significant chemical reactions that occur with ethers:

Cleavage of C-O Bonds in Ethers is a type of bond cleavage.

Cleavage of C-O bonds in ether occurs when there is an excess of hydrogen halide (which is acidic) present, as well as under extreme conditions such as concentrated acids (typically HBr and HI), high temperatures, and excess hydrogen halide.

For example, the reaction of dialkyl ether results in the formation of an alkyl halide and alcohol at the outset. This alcohol reacts with the halide to form a second mole of alkyl halide and water, which is then recycled.

RX has the following reactivity: HI>HBr>HCl

It is well known that the oxygen atom in ether is basic, in the same way that the oxygen atom in alcohol is basic, and that this is true. As a result, the initial reaction between ether and halide results in the formation of protonated ether. The cleavage of the C-O bond occurs as a result of the nucleophilic attack of the halide ion on this protonated ether.

Peroxides are formed during the process of photosynthesis. It is possible to form peroxide linkages when ether is exposed to air in the presence of ultraviolet light or sunlight (UV light or sunlight).

Conclusion 

Ether also has a wide range of applications like, ether is used as a motor fuel in conjunction with gasoline. Diethyl ether is a common solvent for oils, gums, resins, and other similar materials. Because of its high boiling point, phenyl ether has the potential to be used as a heat transfer medium.