Chapter 14, Problem 14.26AP

Interpretation Introduction

(a)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with $\text{HBr}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with $\text{HBr}$ is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with $\text{HBr}$ is shown below.

Figure 1

In the above reaction, hexyne reacts with $\text{HBr}$ to form $\text{2-bromohex-1-ene}$. Hexyne is an unsaturated molecule consisting of a triple bond. It reacts with to form a haloalkene. Therefore, the product on reaction of $\text{1-hexyne}$ with $\text{HBr}$ is shown below.

Figure 2

Conclusion

The product on reaction of $\text{1-hexyne}$ with $\text{HBr}$ is shown in Figure 2.

Interpretation Introduction

(b)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ catalyst is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ catalyst is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ catalyst is shown below.

Figure 3

In the above reaction, hexyne reacts with hydrogen to form hexene. Hexyne is an unsaturated molecule consisting of a triple bond. It reacts hydrogen in presence of $\text{Pd}/\text{C}$ to give alkene. Therefore, the product on reaction of $\text{1-hexyne}$ with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ catalyst is shown below.

Figure 4

Conclusion

The product on reaction of $\text{1-hexyne}$ with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ catalyst is shown in Figure 4.

Interpretation Introduction

(c)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with the ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$, Lindlar’s catalyst is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with the ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$, Lindlar’s catalyst is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with the ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$, Lindlar’s catalyst is shown below.

Figure 5

In the above reaction, hexyne reacts with ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ in presence of Lindlar’s catalyst to form an alkene. Due to the presence of Lindlar’s catalyst the hydrogenation of alkyne stops at alkene and does not proceed further to give alkane. Therefore, the product formed on reaction of $\text{1-hexyne}$ with the ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$ in presence of Lindlar’s catalyst is shown below.

Figure 6

Conclusion

The product on reaction of $\text{1-hexyne}$ with the ${\text{H}}_{\text{2}}\text{,}\text{Pd}/\text{C}$, Lindlar’s catalyst is shown in Figure 6.

Interpretation Introduction

(d)

Interpretation:

The product on reaction of the product formed in part (c) with ${\text{O}}_{\text{3}}$ and then with ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of the product formed in part (c) with ${\text{O}}_{\text{3}}$ and then with ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ is shown below.

Explanation of Solution

The product formed in part (c) is shown below.

Figure 7

The reaction of the product formed in part (c) with ${\text{O}}_{\text{3}}$ and then with ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ is shown below.

Figure 8

The above reaction is known as ozonlysis reaction. In the above reaction, a double bond is cleaved and oxidized to give two products. Reaction of hexene with ${\text{O}}_{\text{3}}$ followed by ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ forms pentanal and formaldehyde. Therefore, the products formed on reaction of the product formed in part (c) with ${\text{O}}_{\text{3}}$ and then with ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ are shown below.

Figure 9

Conclusion

The products on reaction of reaction of the product formed in part (c) with ${\text{O}}_{\text{3}}$ and then with ${\left({\text{CH}}_{\text{3}}\right)}_{\text{2}}\text{S}$ are shown in Figure 9.

Interpretation Introduction

(e)

Interpretation:

The product on reaction of the product formed in part (c) with ${\text{BH}}_{\text{3}}$ in $\text{THF}$, then ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of the product formed in part (c) with ${\text{BH}}_{\text{3}}$ in $\text{THF}$, then ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown below.

Explanation of Solution

The product formed in part (c) is shown below.

Figure 7

The reaction of above compound with ${\text{BH}}_{\text{3}}$ in $\text{THF}$, then ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$

Figure 10

In the above reaction, hexene reacts with boron hydride to form organoborane which further reacts with peroxide to form an alcohol. The alcohol thus formed is by anti-markovnikov addition.

Figure 11

Conclusion

The product on reaction of the product formed in part (c) with ${\text{BH}}_{\text{3}}$ in $\text{THF}$, then ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown in Figure 11.

Interpretation Introduction

(f)

Interpretation:

The product on reaction of the product formed in part (c) with ${\text{Br}}_{\text{2}}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of the product formed in part (c) with ${\text{Br}}_{\text{2}}$ is shown below.

Explanation of Solution

The product formed in part (c) is shown below.

Figure 7

The reaction of above compound with ${\text{Br}}_{\text{2}}$ is shown below.

Figure 12

In the above reaction, hexene being unsaturated reacts with bromine molecule to form a dibromoalkane, that is $\text{1, 2-dibromohexane}$. In the above reaction, unsaturated molecule is forming a saturated dihaloalkane on reaction with bromine molecule. Therefore, the product formed on reaction of product formed in (c) with bromine molecule is shown below.

Figure 13

Conclusion

The product on reaction of the product formed in part (c) with ${\text{Br}}_{\text{2}}$ is shown in Figure 13.

Interpretation Introduction

(g)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with ${\text{NaNH}}_{\text{2}}$ in liquid ammonia is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with ${\text{NaNH}}_{\text{2}}$ in liquid ammonia is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with ${\text{NaNH}}_{\text{2}}$ in liquid ammonia is shown below.

Figure 14

Alkynes react with sodamide $\left({\text{NaNH}}_{\text{2}}\right)$ in presence of liquid ammonia to release an acidic proton and to form an anion of alkyne. Therefore, on reaction of $\text{1-hexyne}$ with ${\text{NaNH}}_{\text{2}}$ in liquid ammonia releases the acidic proton to form an anion of hexyne. The product therefore formed is shown below.

Figure 15

Conclusion

The product on reaction of $\text{1-hexyne}$ with ${\text{NaNH}}_{\text{2}}$ in liquid ammonia is shown in Figure 15.

Interpretation Introduction

(h)

Interpretation:

The product on reaction of the product formed in part (g) with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{I}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of the product formed in part (g) with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{I}$ is shown below.

Explanation of Solution

The product formed in part (g) is shown below.

Figure 15

The reaction of above compound with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{I}$ is shown below.

Figure 16

In the above reaction, the anion of alkyne obtained reacts with iodoethane to form an alkyne of eight carbons. It is non-terminal alkyne, that is, triple bond is not situated at the terminal end. The product formed is shown below.

Figure 17

Conclusion

The product on reaction of the product formed in part (g) with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{I}$ is shown in Figure 17.

Interpretation Introduction

(i)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 18

In the above reaction, hexyne reacts with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ to form a ketone of six carbons. This reaction is also known as oxymercuration-demercuration reaction. In the initial step an enol is formed which tautomerism to form a ketone. Therefore, the product formed on reaction of $\text{1-hexyne}$ with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ is shown below.

Figure 19

Conclusion

The product on reaction of $\text{1-hexyne}$ with ${\text{Hg}}^{\text{2+}}\text{,}{\text{H}}_{\text{2}}{\text{SO}}_{\text{4}}\text{,}{\text{H}}_{\text{2}}\text{O}$ is shown in Figure 19.

Interpretation Introduction

(j)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with disiamyl borane, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of $\text{1-hexyne}$ with disiamyl borane, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with disiamyl borane, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown below.

Figure 20

In the above reaction, hexyne reacts with disiamyl borane to form an organoborane. This reaction is also known as hydroboration-oxidation reaction. The organo-borane gives an enol which tautomerism to form an aldehyde of six carbons. Therefore, the product formed on reaction of $\text{1-hexyne}$ with disiamyl borane, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown below.

Figure 21

Conclusion

The product on reaction of $\text{1-hexyne}$ with disiamyl borane, ${\text{H}}_{\text{2}}{\text{O}}_{\text{2}}/{}^{-}\text{OH}$ is shown in Figure 21.

Interpretation Introduction

(k)

Interpretation:

The product on reaction of $\text{1-hexyne}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The products formed on reaction of $\text{1-hexyne}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether are shown below.

Explanation of Solution

The reaction of $\text{1-hexyne}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether is shown below.

Figure 22

In the above reaction, ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ is Grignard reagent that reacts with alkyne to form an alkane, that is ethane and another Grignard reagent. Hexyne on reaction with Grignard reagent releases the cationic terminal hydrogen which goes on to react with the negative part of Grignard reagent and forms an alkane. The anionic part of alkyne and positive part of Grignard reagent react to form another Grignard reagent. The products therefore obtained are shown below.

Figure 23

Conclusion

The products formed on reaction of $\text{1-hexyne}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ are shown in Figure 23.

Interpretation Introduction

(l)

Interpretation:

The product on reaction of the product formed in part (k) with ethylene oxide and ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is to be stated.

Concept introduction:

The alkynes consist of a triple bond between two carbon atoms. The general formula of alkynes is ${\text{C}}_n{\text{H}}_{2n-2}$. The name of the alkyne compounds ends with suffix $-yne$. Hydrocarbons can also exist in ring like structures.

Answer to Problem 14.26AP

The product on reaction of the product formed in part (k) with ethylene oxide and ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Explanation of Solution

The product formed in part (k) is shown below.

Figure 23

The reaction of above compound with ethylene oxide and ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Figure 24

In the above reaction, the Grignard reagent obtained in part (k) reacts with ethylene oxide followed by hydrolysis to form an alcohol with a triple bond in between the chain. The product formed on reaction of product formed in part (k) with ethylene oxide and ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is shown below.

Figure 25

Conclusion

The product on reaction of the product formed in part (k) with ethylene oxide and ${\text{H}}_{\text{3}}{\text{O}}^{+}$ is in Figure 25.