Question

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

Short answer

The chemical equation for the polymer formation via a condensation reaction between succinic acid and ethylenediamine is: \( n \cdot HOOCCH_2CH_2COOH + n \cdot H_2NCH_2CH_2NH_2 \rightarrow [-OOCCH_2CH_2CONHCH_2CH_2NH-]_{n} + nH_2O \)

Step-by-step solution

Identifying the reactive groups

In the condensation reaction, the functional groups that will react are the carboxyl groups (-COOH) in succinic acid and the amine groups (-NH2) in ethylenediamine. These will form a covalent bond, and a water molecule will be released as a byproduct.

Writing the monomers' chemical formulae

We should write the chemical structures of the monomers, keeping track of the reactive groups: Succinic acid: \( HOOCCH_2CH_2COOH \) Ethylenediamine: \( H_2NCH_2CH_2NH_2 \)

Writing the equation for the condensation reaction

Now we write the chemical equation for the reaction between the succinic acid and ethylenediamine. In this case, one amine group will react with one carboxyl group, forming an amide bond (-CONH-) and releasing a water molecule. The reaction occurs as follows: \( HOOCCH_2CH_2COOH + H_2NCH_2CH_2NH_2 \rightarrow HOOCCH_2CH_2CONHCH_2CH_2NH_2 + H_2O \)

Generalizing the equation for polymer formation

The reaction above generates a dimer, which still has an unreacted carboxyl group on one end and an unreacted amine group on the other end. As these groups continue to react with other monomers, a polymer chain will form. The general equation for the polymerization reaction can be written as: \( n \cdot HOOCCH_2CH_2COOH + n \cdot H_2NCH_2CH_2NH_2 \rightarrow [-OOCCH_2CH_2CONHCH_2CH_2NH-]_{n} + nH_2O \) Here, [-OOCCH_2CH_2CONHCH_2CH_2NH-] represents the repeating unit of the polymer chain, and n is the number of times this unit repeats in the chain. In conclusion, the chemical equation for the polymer formation via a condensation reaction between succinic acid and ethylenediamine is: \( n \cdot HOOCCH_2CH_2COOH + n \cdot H_2NCH_2CH_2NH_2 \rightarrow [-OOCCH_2CH_2CONHCH_2CH_2NH-]_{n} + nH_2O \)

Key concepts

Polymer Chemistry

Polymer chemistry is a subfield of chemistry that focuses on the synthesis, structure, and properties of polymers, which are large molecules composed of repeating structural units. These units, known as monomers, can be connected in various ways to form polymers with diverse characteristics. Condensation polymerization is a common method used to link monomers together through a chemical reaction where small molecules like water are released.

Understanding polymer chemistry is akin to learning how to build with molecular scale Lego blocks, where the way you connect the blocks determines the properties of your final construction. Different types of bonds can be tailored during the polymerization process, leading to materials with unique features like plasticity, elasticity, or toughness, which are essential in various industries ranging from packaging to aerospace.

Chemical Equations

Chemical equations are symbolic representations of chemical reactions, with reactants shown on the left and products on the right. They must be balanced, meaning the number of atoms for each element should be the same on both sides of the equation. This reflects the conservation of mass.

When writing equations for polymerization, it's vital to illustrate both the small and large-scale interactions between monomers. In condensation polymerization, not only do we represent the initial reaction, but we also generalize the equation to show the repeating nature of the process that leads to the polymer chain. This offers a clear roadmap for students to envision how individual monomer units contribute to the growing polymer.

Functional Groups

Functional groups are specific groups of atoms within molecules that have characteristic properties and reactivities. In the realm of polymer chemistry, functional groups determine how monomers can join together.

Common functional groups involved in condensation polymerization are carboxylic acids (-COOH) and amines (-NH2). The carboxylic acid of one monomer reacts with the amine of another, creating an amide bond while releasing a molecule of water. This interplay of functional groups dictates the structure and, ultimately, the properties of the synthesized polymer, which is why students must become adept at recognizing and predicting the behavior of these critical molecular players.

Amide Bond Formation

The amide bond (-CONH-) is a key linkage in the formation of many synthetic polymers and biological molecules like proteins. During condensation polymerization, when an amine group reacts with a carboxylic acid group, an amide linkage is formed, and water is released as a byproduct.

This process is a fantastic example of how two functional groups can come together to create a new type of chemical bond. The integrity and stability of the amide bond are pivotal as they influence the durability and resilience of materials, from nylon fibers to Kevlar vests. Students should appreciate the significance of this bond as it underpins the performance of many materials they interact with daily.