Chapter 26, Problem 26.42P

Interpretation Introduction

(a)

Interpretation:

A mechanism for the initiation step for the polymerization reaction of the given compound is to be determined.

Concept introduction:

The chemical reaction in which the monomer molecules reacts together to form polymer chains or three dimentional networks is termed as polymerization. This are classified by different syatem avaible for the different types if polymerization.

The polymerizations can be initiated by anions or cations, resulting in anionic polymerization or cationic polymerization, respectively. The polymerization involves, 1) initiation, 2) propagation, and 3) termination.

Initiation is the first step of the polymerization process. An active center is created during initiation, from which a polymer chain is generated. Not all monomers are susceptible to all types of initiators.

In propogation a reactive intermediate is repetitively redeveloped throughout the sequence of a chemical chain reaction. Then it is terminated by adding mono functional groups that having equal of different types of monomer.

Answer to Problem 26.42P

The initiation step for the polymerization reaction of the given compound is as follows.

Explanation of Solution

The alkene reacts with ${\text{OH}}^{\text{-}}$ in a nucleophilic addition step to form a carbanion. The $\text{CN }$ and ${\text{CO}}_{\text{2}}{\text{CH}}_{\text{3}}$ groups stabilize nearby negative charges, so ${\text{OH}}^{\text{-}}$ attacks the C atom without the attached $\text{CN }$ and ${\text{CO}}_{\text{2}}{\text{CH}}_{\text{3}}$ groups to produce the negative charge on C that has those groups attached.

Conclusion

The given explanation is obtained by applying the concept polymerization mechanism.

Interpretation Introduction

(b)

Interpretation:

A mechanism for the propagation step for the polymerization reaction of the given compound is to be determined.

Concept introduction:

The chemical reaction in which the monomer molecules reacts together to form polymer chains or three dimentional networks is termed as polymerization. This are classified by different syatem avaible for the different types if polymerization.

The polymerizations can be initiated by anions or cations, resulting in anionic polymerization or cationic polymerization, respectively. The polymerization involves, 1) initiation, 2) propagation, and 3) termination.

Initiation is the first step of the polymerization process. An active center is created during initiation, from which a polymer chain is generated. Not all monomers are susceptible to all types of initiators.

In propogation a reactive intermediate is repetitively redeveloped throughout the sequence of a chemical chain reaction. Then it is terminated by adding mono functional groups that having equal of different types of monomer.

Answer to Problem 26.42P

The propagation step for the polymerization reaction of the given compound is as follows.

Explanation of Solution

The carbanion formed in initiation step reacts with another equivalent of $\text{methyl 2-cyanoacrylate}$

in the first nucleophilic addition step. The propagation step repeats the nucleophilic addition reaction.

Conclusion

The given explanation is obtained by applying the concept polymerization mechanism.

Interpretation Introduction

(c)

Interpretation:

The structure of $\text{poly}\left(\text{methyl2-cyanoacrylate}\right)$ is to be determined.

Concept introduction:

The chemical reaction in which the monomer molecules reacts together to form polymer chains or three dimentional networks is termed as polymerization. This are classified by different syatem avaible for the different types if polymerization.

The polymerizations can be initiated by anions or cations, resulting in anionic polymerization or cationic polymerization, respectively. The polymerization involves, 1) initiation, 2) propagation, and 3) termination.

Initiation is the first step of the polymerization process. An active center is created during initiation, from which a polymer chain is generated. Not all monomers are susceptible to all types of initiators.

In propogation a reactive intermediate is repetitively redeveloped throughout the sequence of a chemical chain reaction. Then it is terminated by adding mono functional groups that having equal of different types of monomer.

Answer to Problem 26.42P

The structure of $\text{poly}\left(\text{methyl2-cyanoacrylate}\right)$ is given below.

Explanation of Solution

The propagation step repeats the nucleophilic addition reaction to produce $\text{poly}\left(\text{methyl2-cyanoacrylate}\right)$.

Conclusion

The given explanation is obtained by applying the concept polymerization mechanism.

Interpretation Introduction

(d)

Interpretation:

Why is $\text{methyl 2-cyanoacrylate}$ a better candidate for anionic polymerization than $\text{methyl acrylate}$ is to be explained.

Concept introduction:

The chemical reaction in which the monomer molecules reacts together to form polymer chains or three dimentional networks is termed as polymerization. This are classified by different syatem avaible for the different types if polymerization.

The polymerizations can be initiated by anions or cations, resulting in anionic polymerization or cationic polymerization, respectively. The polymerization involves, 1) initiation, 2) propagation, and 3) termination.

Initiation is the first step of the polymerization process. An active center is created during initiation, from which a polymer chain is generated. Not all monomers are susceptible to all types of initiators.

In propogation a reactive intermediate is repetitively redeveloped throughout the sequence of a chemical chain reaction. Then it is terminated by adding mono functional groups that having equal of different types of monomer.

Answer to Problem 26.42P

$\text{Methyl 2-cyanoacrylate}$ a better candidate for anionic polymerization than methyl acrylate because of the presence of $\text{C}\equiv \text{N}$ group due to which it is resonance stabilized.

Explanation of Solution

$\text{Methyl 2-cyanoacrylate}$ forms a carbanion intermediate that is stabilized by the $\text{C}\equiv \text{N}$ group via resonance and inductive effects. Methyl acrylate has less resonance stabilization because it lacks $\text{C}\equiv \text{N}$ attached to C^- that develops on the growing polymer chain. Thus, methyl 2-cyanoacrylate polymerizes faster.

Conclusion

The given explanation is obtained by applying the concept polymerization mechanism, resonance and inductive effect.

Interpretation Introduction

(e)

Interpretation:

Why or why not methyl 2-cyanoacrylate would be a good candidate for cationic polymerization is to be explained.

Concept introduction:

The chemical reaction in which the monomer molecules reacts together to form polymer chains or three dimentional networks is termed as polymerization. This are classified by different syatem avaible for the different types if polymerization.

The polymerizations can be initiated by anions or cations, resulting in anionic polymerization or cationic polymerization, respectively. The polymerization involves, 1) initiation, 2) propagation, and 3) termination.

Initiation is the first step of the polymerization process. An active center is created during initiation, from which a polymer chain is generated. Not all monomers are susceptible to all types of initiators.

In propogation a reactive intermediate is repetitively redeveloped throughout the sequence of a chemical chain reaction. Then it is terminated by adding mono functional groups that having equal of different types of monomer.

Answer to Problem 26.42P

$\text{Methyl 2-cyanoacrylate}$ would not be a good candidate for cationic polymerization.

Explanation of Solution

$\text{Methyl 2-cyanoacrylate}$ is not likely to polymerize through a cation polymerization mechanism because the cation would be unstable owing to the electron-withdrawing $\text{CN}$ and ${\text{CO}}_{\text{2}}{\text{CH}}_{\text{3}}$ groups. Both of those groups would destabilize the ${\text{C}}^{\text{+}}$ in the growing polymer chain.

Conclusion

The given explanation is obtained by applying the concept polymerization mechanism.