Chapter 14, Problem 14E

To determine

The name and the condensed structural formula of constitutional isomers of a continuous chain of heptene.

Answer to Problem 14E

There are three constitutional isomers of a continuous chain of heptene. The name of three isomers is $\text{1-heptene}$, $\text{2-heptene}$ and $\text{3-heptene}$.

The condensed structural formula for $\text{1-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}={\text{CH}}_{\text{2}}\\ \text{ 1-heptene}\end{array}$

The condensed structural formula for $\text{2-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_3\\ \text{ 2-heptene}\end{array}$

The condensed structural formula for $\text{3-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_2-{\text{CH}}_3\\ \text{ 3-heptene}\end{array}$

Explanation of Solution

Given Info: The given compound is heptene, ${\text{C}}_{\text{7}}{\text{H}}_{\text{14}}$.

Explanation:

The isomer in which molecules have same molecular formula but different structural formula are called constitutional isomers.

Draw a continuous chain of seven carbon atoms joined by six single bonds and since the valency of carbon atom is four, add enough bonds to each carbon atom so that all carbon atoms have four bonds.

The constitutional isomers of heptene are $\text{1-heptene}$, $\text{2-heptene}$, $\text{3-heptene}$, $\text{4-heptene}$, $\text{5-heptene}$ and $\text{6-heptene}$.

A number preceding the name indicates the carbon atom on which the double bond starts. The carbons in the chain are numbered starting at the end that gives the double bond the lower number.

The condensed structural formula for $\text{1-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}={\text{CH}}_{\text{2}}\\ \text{ 1-heptene}\end{array}$

The condensed structural formula for $\text{2-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_3\\ \text{ 2-heptene}\end{array}$

The condensed structural formula for $\text{3-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_2-{\text{CH}}_3\\ \text{ 3-heptene}\end{array}$

The structure of $\text{4-heptene}$, $\text{5-heptene}$ and $\text{6-heptene}$ is similar to the structure of $\text{3-heptene}$, $\text{2-heptene}$ and $\text{1-heptene}$ respectively because the carbons in the chain are numbered starting at the end that gives the double bond the lower number.

Therefore, there are three constitutional isomers of a continuous chain of heptene that is $\text{1-heptene}$, $\text{2-heptene}$ and $\text{3-heptene}$.

Conclusion:

Therefore, there are three constitutional isomers of a continuous chain of heptene. The name of three isomers is $\text{1-heptene}$, $\text{2-heptene}$ and $\text{3-heptene}$.

The condensed structural formula for $\text{1-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}={\text{CH}}_{\text{2}}\\ \text{ 1-heptene}\end{array}$

The condensed structural formula for $\text{2-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_3\\ \text{ 2-heptene}\end{array}$

The condensed structural formula for $\text{3-heptene}$ is,

$\begin{array}{l}{\text{CH}}_{\text{3}}-{\text{CH}}_{\text{2}}-{\text{CH}}_{\text{2}}-\text{CH}=\text{CH}-{\text{CH}}_2-{\text{CH}}_3\\ \text{ 3-heptene}\end{array}$