Chapter 23, Problem 23.44AP

Interpretation Introduction

(a)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with dilute $\text{HBr}$ is to be stated.

Concept introduction:

Amines are the organic compounds that are formed by replacement of hydrogen from ammonia with a substituent. It may be alkyl or aryl group. Amines are basic in nature because the nitrogen can donate its lone pairs and it also has the ability of the nitrogen to accept the proton in water.

Answer to Problem 23.44AP

The product obtained in the reaction of $p\text{-chloroaniline}$ with dilute $\text{HBr}$ is $4\text{-chlorobenzenaminium bromide}$. The reaction is shown below.

Explanation of Solution

When $p\text{-chloroaniline}$ reacts with dilute $\text{HBr}$, it results in the formation of ammonium salt that is $4\text{-chlorobenzenaminium bromide}$. The reaction is shown below.

Figure 1

Conclusion

The product obtained in the reaction of $p\text{-chloroaniline}$ with dilute $\text{HBr}$ is $4\text{-chlorobenzenaminium bromide}$ as shown in Figure 1.

Interpretation Introduction

(b)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether is to be stated.

Concept introduction:

Amines are the organic compounds that are formed by replacement of hydrogen from ammonia with a substituent. It may be alkyl or aryl group. When alcohol reacts with hydrogen halide it forms alkyl halide that reacts with magnesium metal to form Grignard reagent. The Grignard reagent required in various organic synthesis.

Answer to Problem 23.44AP

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether is a salt of $\text{(4-chlorophenyl)amine}$. The reaction is shown below.

Explanation of Solution

The reaction of $p\text{-chloroaniline}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether results in the abstraction of a proton from an amine and forms a salt of $\text{(4-chlorophenyl)amine}$. The reaction is shown below.

Figure 2

Conclusion

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{CH}}_{\text{3}}{\text{CH}}_{\text{2}}\text{MgBr}$ in ether is a salt of $\text{(4-chlorophenyl)amine}$.

Interpretation Introduction

(c)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{NaNO}}_{\text{2}}$ and $\text{HCl}$ at $\text{0}°\text{C}$ is to be stated.

Concept introduction:

The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces ${\text{N}}_{\text{2}}$ (a very good leaving group) to form corresponding products. Mechanisms of these reactions vary with the nature of Z, where Z is an atom or group of atoms.

Answer to Problem 23.44AP

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{NaNO}}_{\text{2}}$ and $\text{HCl}$ at $\text{0}°\text{C}$ is $4\text{-chlorobenzenaminium chloride}$. The reaction is shown below.

Explanation of Solution

When $p\text{-chloroaniline}$ undergoes diazonium reaction with ${\text{NaNO}}_{\text{2}}$ and $\text{HCl}$ at $\text{0}°\text{C}$, it results in the formation of diazonium salt that is used to synthesis various organic compounds. The reaction is shown below.

Figure 3

Conclusion

The product obtained in the reaction of $p\text{-chloroaniline}$ with ${\text{NaNO}}_{\text{2}}$ and $\text{HCl}$ at $\text{0}°\text{C}$ is $4\text{-chlorobenzenaminium chloride}$.

Interpretation Introduction

(d)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with $p\text{-toluenesulfonyl chloride}$ is to be stated.

Concept introduction:

Amines are the organic compounds that are formed by replacement of hydrogen from ammonia with a substituent. It may be alkyl or aryl group. Amines are basic in nature because the nitrogen can donate its lone pairs and also the ability of the nitrogen to accept the proton in water.

Answer to Problem 23.44AP

The product $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide hydrochloride}$ is obtained on the reaction of $p\text{-chloroaniline}$ with $p\text{-toluenesulfonyl chloride}$. The reaction is shown below.

Explanation of Solution

When $p\text{-chloroaniline}$ reacts with $p\text{-toluenesulfonyl chloride}$, it results in the formation of sulfonamide chlorides. The reaction is shown below.

Figure 4

Conclusion

The product $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide hydrochloride}$ is obtained on the reaction of $p\text{-chloroaniline}$ with $p\text{-toluenesulfonyl chloride}$.

Interpretation Introduction

(e)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (c) followed by ${\text{H}}_{\text{2}}{\text{O, Cu}}_{\text{2}}\text{O and Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}$ is to be stated.

Concept introduction:

Amines are the organic compounds that are formed by replacement of hydrogen from ammonia with a substituent. It may be alkyl or aryl group. The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces ${\text{N}}_{\text{2}}$ (a very good leaving group) to form corresponding products.

Answer to Problem 23.44AP

The product $\text{4-chlorophenol}$ is obtained in the reaction of the product of part (c) with ${\text{H}}_{\text{2}}{\text{O, Cu}}_{\text{2}}\text{O and Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}$. The reaction is shown below.

Explanation of Solution

When $\text{4-chlorobenzenediazonium chloride}$ reacts with ${\text{H}}_{\text{2}}{\text{O, Cu}}_{\text{2}}\text{O and Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}$ it results in the formation of $\text{4-chlorophenol}$. The diazonium salt is replaced by a hydroxyl group. This reaction is a similar type of Sandmeyer reaction. The reaction is shown below.

Figure 5

Conclusion

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (c) followed by ${\text{H}}_{\text{2}}{\text{O, Cu}}_{\text{2}}\text{O and Cu}{\left({\text{NO}}_{\text{3}}\right)}_{\text{2}}$ is $\text{4-chlorophenol}$ as shown in Figure 5.

Interpretation Introduction

(f)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (c) and $\text{CuBr}$ is to be stated.

Concept introduction:

The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces ${\text{N}}_{\text{2}}$ (a very good leaving group) to form corresponding products. Sandmeyer reaction is used to synthesis alkyl halides from salts of copper.

Answer to Problem 23.44AP

The product $\text{1-bromo-4-chlorobenzene}$ is obtained in the reaction of part (c) with $\text{CuBr}$. The reaction is shown below.

Explanation of Solution

When $\text{4-chlorobenzenediazonium chloride}$ undergoes Sandmeyer reaction with copper salt, $\text{CuBr}$ and results in the formation of $\text{1-bromo-4-chlorobenzene}$. The diazonium salt is replaced by a bromine atom. The reaction is shown below.

Figure 6

Conclusion

The product $\text{1-bromo-4-chlorobenzene}$ is obtained in the reaction of part (c) with $\text{CuBr}$.

Interpretation Introduction

(g)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (c) and ${\text{H}}_{\text{3}}{\text{PO}}_{\text{2}}$ is to be stated

Concept introduction:

The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces ${\text{N}}_{\text{2}}$ (a very good leaving group) to form corresponding products. The reduction reaction of the diazonium salt with hypophosphorous acid and sodium stannite leads to the formation of benzene.

Answer to Problem 23.44AP

The product chlorobenzene is obtained in the reaction of the product of part (c) and ${\text{H}}_{\text{3}}{\text{PO}}_{\text{2}}$. The reaction is shown below.

Explanation of Solution

The reduction reaction of $\text{4-chlorobenzenediazonium chloride}$ with ${\text{H}}_{\text{3}}{\text{PO}}_{\text{2}}$ result in the formation of chlorobenzene. The diazonium salt is replaced by a hydrogen atom. The reaction is shown below.

Figure 7

Conclusion

The product chlorobenzene is obtained in the reaction of the product of part (c) and ${\text{H}}_{\text{3}}{\text{PO}}_{\text{2}}$.

Interpretation Introduction

(h)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (c) and $\text{CuCN}$ is to be stated.

Concept introduction:

The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces ${\text{N}}_{\text{2}}$ (a very good leaving group) to form corresponding products. Sandmeyer reaction is used to synthesis alkyl halides from salts of copper.

Answer to Problem 23.44AP

The product, $\text{4-chlorobenzonitrile}$ is obtained in the reaction of the product of part (c) with $\text{CuCN}$. The reaction is shown below.

Explanation of Solution

When $\text{4-chlorobenzenediazonium chloride}$ reacts with $\text{CuCN}$ it undergoes Sandmeyer reaction leads to the formation of $\text{4-chlorobenzonitrile}$. The diazonium salt is replaced by a cyanide group. The reaction is shown below.

Figure 8

Conclusion

The product, $\text{4-chlorobenzonitrile}$ is obtained in the reaction of the product of part (c) with $\text{CuCN}$.

Interpretation Introduction

(i)

Interpretation:

The product obtained in the reaction of $p\text{-chloroaniline}$ with product of part (d) and $\text{NaOH}$ at $\text{25}°\text{C}$ is to be stated.

Concept introduction:

The formation of diazonium salt from aromatic amines takes place using sodium nitrite and hydrochloric acid at low temperatures. Aryl diazonium salts undergo a variety of specific substitution reactions in which the incoming Z group replaces N₂ (a very good leaving group) to form corresponding products.

Answer to Problem 23.44AP

The product $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide}$ is obtained when the product of part (d) reacts with $\text{NaOH}$ at $\text{25}°\text{C}$. The reaction is shown below.

Explanation of Solution

When $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide hydrochloride}$ reacts with $\text{NaOH}$ at $\text{25}°\text{C}$, it results in the formation of $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide}$. The reaction is an example of a neutralization reaction. The reaction is shown below.

Figure 9

Conclusion

The product $\text{N-}\left(\text{4-chlorophenyl}\right)\text{-4-methylbenzenesulphonamide}$ is obtained when the product of part (d) reacts with $\text{NaOH}$ at $\text{25}°\text{C}$.