Chapter 17, Problem 21P

Interpretation Introduction

Interpretation: The structures of all the constitutionally isomeric ethers of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ have to be drawn and an acceptable name for each isomer has to be stated.

Concept introduction:

The compounds that have the identical molecular formula but have different connectivity of atoms are termed as constitutional isomers. The constitutional isomers are also known as structural isomers.

The names of the different compounds of ether can be determined by using the IUPAC convention for naming compounds.

Answer to Problem 21P

The structures of all the constitutionally isomeric ethers of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ and their acceptable names are shown below.

Explanation of Solution

The different constitutionally isomeric ethers that can be written for the given molecular formula, that is, ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ are shown below.

In the above isomeric form, a butyl and a methyl group are attached with the oxygen atom. Therefore, the acceptable name for this isomer is Butyl methyl ether.

Another constitutional isomer for ether of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ is shown below.

The oxygen atom is attached to the second carbon of the butyl group and a methyl group. Therefore, the acceptable name for this isomer is 2-butyl methyl ether.

Another constitutional isomer for ether of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ is as follows.

In this isomeric ether, the oxygen atom is attached to a methyl group and a tertiary butyl group. Therefore, the acceptable name for this isomer is tert-butyl methyl ether.

Another constitutional isomer for ether of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ is shown below.

In this isomeric form of ether, the oxygen atom is attached to a methyl group and an isobutyl group. Therefore, the acceptable name for this isomer is isobutyl methyl ether.

Another constitutional isomer for ether of the given molecular formula is shown below.

The oxygen atom in the above isomeric form of ether is attached to an ethyl and a propyl group. Therefore, the acceptable name for this isomer is ethyl propyl ether.

Another constitutional isomer for ether of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$ is shown below.

In this isomeric ether, the oxygen atom is attached to an isopropyl and an ethyl group. Therefore, the acceptable name for this isomer is isopropyl ethyl ether.

Conclusion

There are total six constitutional isomers for the ether of molecular formula ${\text{C}}_{\text{5}}{\text{H}}_{\text{12}}\text{O}$. Their structural formulas can be formed by varying the positions of different groups in the molecule.