Problem 86 - Chemistry The Central Science

Question

Write a balanced chemical equation for the formation of polymer via a condensation reaction from the monomers succinic acid (HOOCCH \(_{2} \mathrm{CH}_{2} \mathrm{COOH}\) ) and ethylenediamine \(\left(\mathrm{H}_{2} \mathrm{NCH}_{2} \mathrm{CH}_{2} \mathrm{NH}_{2}\right)\)

Step-by-Step Solution

Answer

The balanced chemical equation for the formation of the polymer via a condensation reaction between succinic acid and ethylenediamine is: \[ n\left( \mathrm{HOOCCH}_{2}\mathrm{CH}_{2}\mathrm{COOH}\right) + n\left( \mathrm{H}_{2}\mathrm{NCH}_{2}\mathrm{CH}_{2}\mathrm{NH}_{2}\right) \rightarrow \left[ \mathrm{-(OOCCH}_{2}\mathrm{CH}_{2}\mathrm{CO)}_{n}\mathrm{NHCH}_{2}\mathrm{CH}_{2}\mathrm{NH}- \right] + n \left( \mathrm{H}_{2}\mathrm{O} \right) \] This equation represents the formation of the polymer, consisting of alternating succinic acid and ethylenediamine units with amide linkages, and the release of water molecules in the process.

Step 1: Identify the functional groups that will react in condensation reaction

In both monomers, there are functional groups that react with one another: the carboxylic acid group (-COOH) of succinic acid, and the amine group (-NH2) of ethylenediamine. These two functional groups will react in a condensation reaction, forming an amide linkage.

Step 2: Write the balanced chemical equation for the reaction between succinic acid and ethylenediamine

We will now write the balanced chemical equation for the reaction between one molecule of succinic acid and one molecule of ethylenediamine: \[ \mathrm{HOOCCH}_{2}\mathrm{CH}_{2}\mathrm{COOH} + \mathrm{H}_{2}\mathrm{NCH}_{2}\mathrm{CH}_{2}\mathrm{NH}_{2} \rightarrow \] \[ \mathrm{HOOCCH}_{2}\mathrm{CH}_{2}\mathrm{CONHCH}_{2}\mathrm{CH}_{2}\mathrm{NH}_{2} + \mathrm{H}_{2}\mathrm{O} \] In this equation, one carboxylic acid group of succinic acid reacted with one amine group of ethylenediamine, forming an amide linkage and a water molecule.

Step 3: Write the balanced chemical equation for the polymer formation

Now that we have the chemical equation for the reaction between the monomers, we will write the balanced chemical equation for the polymer formation via condensation reaction: \(n\) molecules of succinic acid + \(n\) molecules of ethylenediamine \(\rightarrow\) Polymer + \(n\) molecules of water \[ n\left( \mathrm{HOOCCH}_{2}\mathrm{CH}_{2}\mathrm{COOH}\right) + n\left( \mathrm{H}_{2}\mathrm{NCH}_{2}\mathrm{CH}_{2}\mathrm{NH}_{2}\right) \rightarrow \] \[ \left[ \mathrm{-(OOCCH}_{2}\mathrm{CH}_{2}\mathrm{CO)}_{n}\mathrm{NHCH}_{2}\mathrm{CH}_{2}\mathrm{NH}- \right] + n \left( \mathrm{H}_{2}\mathrm{O} \right) \] This balanced chemical equation represents the formation of the polymer by condensation reaction between succinic acid and ethylenediamine monomers. The polymer chain consists of alternating succinic acid and ethylenediamine units with amide linkages.

Key Concepts

Polymer Formation

Polymer formation is a process where smaller molecules, called monomers, join together to form long chains known as polymers. This process can occur through several different mechanisms, one of the most common being condensation reactions.

In condensation polymerization, monomers link through a chemical reaction that usually releases a small molecule such as water or methanol. Each time a new monomer is added, a by-product, typically water, is released. This is why the reaction is called a "condensation" reaction.

The final polymer is a large structure made of repeating units of the monomers, which are linked by the specific types of chemical bonds formed during the reactions. These polymers can have diverse applications depending on their structure and the types of monomers used.

Succinic Acid

Succinic acid is an important organic compound with the formula \ \(\mathrm{HOOCCH}_{2}\mathrm{CH}_{2}\mathrm{COOH} \ \). It is a dicarboxylic acid, meaning it has two carboxylic acid groups (\(-COOH\)).

These carboxylic groups are highly reactive in condensation polymerizations, allowing succinic acid to act as a monomer when forming polymers. When it reacts in a condensation reaction, it typically loses one molecule of water per linkage formed.

This property makes succinic acid a crucial building block in the creation of many biodegradable polymers. Because of its natural occurrence and eco-friendly profile, succinic acid is often used in green chemistry applications.

Ethylenediamine

Ethylenediamine is a type of organic compound that contains two amine groups, signified by \ \(\mathrm{H}_{2}\mathrm{NCH}_{2}\mathrm{CH}_{2}\mathrm{NH}_{2} \ \). Known as a diamine, it is highly reactive, particularly with carboxylic acids.

In condensation polymerizations, ethylenediamine's amine groups can react with the carboxylic acid groups of monomers like succinic acid. This reaction leads to the formation of an amide bond, which is strong and stable. Ethylenediamine's two amine groups make it well-suited for building cross-linked, durable polymer networks.

Because of its high reactivity, ethylenediamine is commonly used in the production of polyamides and other complex polymers that require robust chemical interlinkages.

Amide Linkage

Amide linkages are a type of bond formed when a carboxylic acid group reacts with an amine group. This reaction, often referred to as a condensation reaction, results in the formation of an amide bond and the release of a water molecule.

In the context of polymer chemistry, amide linkages are crucial as they form the backbone of many synthetic and natural polymers, such as proteins and nylons. The formation of an amide bond involves the connection of the nitrogen atom from the amine group to the carbon atom of the carboxylic acid group after the release of water.

The strength and stability of amide linkages make them essential in various materials that require durability and endurance, significantly enhancing the polymer's properties.