Question

Give the common name for each of the following ethers: (a) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{3}\) (b) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{3}\) (c) \(\mathrm{CH}_{3} \mathrm{CH}_{2} \mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2} \mathrm{CH}_{2} \mathrm{CH}_{3}\) d.

Short answer

(a) Dimethyl Ether, (b) Methyl Ethyl Ether, (c) Dipropyl Ether.

Step-by-step solution

Understanding the Structure

Ethers have a structural formula of R-O-R', where R and R' are alkyl groups. To name them, identify the alkyl groups on either side of the oxygen atom.

Naming (a)

For (a) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{3}\), the ether consists of two identical alkyl groups, both being \(\mathrm{CH}_{3}\) (methyl groups). The common name for this ether is Dimethyl Ether.

Naming (b)

For (b) \(\mathrm{CH}_{3}-\mathrm{O}-\mathrm{CH}_{2}\mathrm{CH}_{3}\), the alkyl groups on either side of the oxygen are methyl (\(\mathrm{CH}_{3}\)) and ethyl (\(\mathrm{CH}_{2}\mathrm{CH}_{3}\)). The common name for this ether is Methyl Ethyl Ether.

Naming (c)

For (c) \(\mathrm{CH}_{3}\mathrm{CH}_{2}\mathrm{CH}_{2}-\mathrm{O}-\mathrm{CH}_{2}\mathrm{CH}_{2}\mathrm{CH}_{3}\), both sides of the ether have a propyl group (\(\mathrm{CH}_{2}\mathrm{CH}_{2}\mathrm{CH}_{3}\)). The common name for this ether is Dipropyl Ether.

Key concepts

Alkyl groups

Alkyl groups are fundamental building blocks in organic chemistry. They are derived from alkanes by removing one hydrogen atom, creating a point of attachment. An alkyl group can be represented as \(-C_nH_{2n+1}\), where 'n' is the number of carbon atoms. Common alkyl groups include methyl \(\text{(CH}_3\text{)}\), ethyl \(\text{(CH}_2\text{CH}_3\text{)}\), and propyl \(\text{(CH}_2\text{CH}_2\text{CH}_3\text{)}\).

These alkyl groups are often part of a larger molecule, such as ethers. Ethers feature two alkyl groups bonded to an oxygen atom, typically identified in a general form \( R-O-R' \). Recognizing these groups is crucial for naming ethers and understanding their properties.

A few key points about alkyl groups:

• They determine the physical and chemical properties of the ether.
• The naming of ethers depends on the identity of the alkyl groups on either side of the oxygen.

Dimethyl Ether

Dimethyl ether (DME) is one of the simplest forms of ethers. Its molecular formula is \(\text{CH}_3-\text{O}-\text{CH}_3\), indicating that both alkyl groups on either side of the oxygen are methyl groups. Because these alkyl groups are identical, we use the word 'di' to denote their presence, thus forming the name "dimethyl ether."

Dimethyl ether is a colorless gas that has various applications, from being used as a propellant in aerosol products to serving as a potential clean-burning fuel. Here's a list of key characteristics:

• Both alkyl groups are methyl, making it symmetrical.
• Emphasizes understanding in organic chemistry for naming conventions.
• Relatively low boiling point due to its simple structure.

Dimethyl ether exemplifies how basic alkyl groups form the backbone of more complex organic structures.

Methyl Ethyl Ether

Methyl ethyl ether, with the chemical structure \(\text{CH}_3-\text{O}-\text{CH}_2\text{CH}_3\), includes a methyl group on one side of the oxygen and an ethyl group on the other. This arrangement gives it an asymmetrical form. In naming this ether, each side of the oxygen atom has different alkyl groups, which is reflected in the name "methyl ethyl ether."

The presence of different alkyl groups affects various properties of the ether. Here’s how:

• The boiling point is higher than that of dimethyl ether due to ethyl's larger alkyl chain.
• It illustrates the complex nomenclature based on alkyl group variation.
• Its uses span industrial applications, such as a solvent or starting materials for synthesis.

Understanding methyl ethyl ether's structure is key for students learning about chemical naming conventions and ether-related chemistry.

Dipropyl Ether

Dipropyl ether, a more complex form of ether, is made up of two propyl groups bonded across an oxygen atom. Its chemical structure is \(\text{CH}_2\text{CH}_2\text{CH}_3-\text{O}-\text{CH}_2\text{CH}_2\text{CH}_3\). As the propyl groups are considered identical, the term "di" is used to describe their pair, leading to the name "dipropyl ether."

Unlike simpler ethers, dipropyl ether has multiple carbon atoms, influencing its physical properties and uses. Here's a deeper look:

• Larger alkyl groups result in a higher boiling point due to increased van der Waals forces.
• It's used as a solvent and in manufacturing processes because of its stability and properties.
• The dipropyl configuration showcases how increasing chain length impacts ether characteristics.

Dipropyl ether helps illustrate the diversity in ether compounds, enhancing our understanding of organic chemistry and functional groups.