Question

Write equations for the following reactions, representing the reactants and products using structural formulas. (a) The hydrolysis of the amide \(\mathrm{C}_{6} \mathrm{H}_{5} \mathrm{CONHCH}_{3}\) to form benzoic acid and methylamine (b) The hydrolysis of \(+\mathrm{CO}\left(\mathrm{CH}_{2}\right)_{4} \mathrm{CONH}\left(\mathrm{CH}_{2}\right)_{6} \mathrm{NH} \rightarrow_{n}\) (nylon-6,6, a polyamide) to give a carboxylic acid and an amine

Short answer

Hydrolysis of amides splits bonds to form carboxylic acids and amines; nylon-6,6 yields adipic acid and hexamethylene diamine.

Step-by-step solution

Understanding Hydrolysis

Hydrolysis involves the reaction of a compound with water, resulting in the breaking of a bond and the formation of two or more products. In the case of amides, hydrolysis typically results in the formation of a carboxylic acid and an amine.

Structural Formula of Amide Hydrolysis (a)

For the hydrolysis of the amide \( \text{C}_6\text{H}_5\text{CONHCH}_3 \), the structural reaction involves:- Reactant: \( \text{C}_6\text{H}_5\text{CONHCH}_3 \) (an amide with a benzene ring).- Water \( \text{H}_2\text{O} \) splitting the amide bond.- Products: Benzoic acid \( \text{C}_6\text{H}_5\text{COOH} \) and methylamine \( \text{CH}_3\text{NH}_2 \).Structural formula reaction:\[ \text{C}_6\text{H}_5\text{C}(=\text{O})\text{NHCH}_3 + \text{H}_2\text{O} \rightarrow \text{C}_6\text{H}_5\text{C}(=\text{O})\text{OH} + \text{CH}_3\text{NH}_2 \]

Nylon-6,6 Hydrolysis (b)

Nylon-6,6 consists of repeating amide units. The hydrolysis of this polymer can be simplified to the breaking of the amide bonds. For the monomer:- Reactant: \(+\text{CO}(\text{CH}_2)_4\text{CONH}(\text{CH}_2)_6\text{NH}- \) repeated \( n \) times.- Products formed upon hydrolysis are adipic acid, \( \text{HOOC}(\text{CH}_2)_4\text{COOH} \), and hexamethylene diamine, \( \text{H}_2\text{N}(\text{CH}_2)_6\text{NH}_2 \).Simplified structural formula representation:\[ {n} \cdot \left( \text{HOOC}(\text{CH}_2)_4\text{CO-NH}(\text{CH}_2)_6\text{NH} \right) + n \text{H}_2\text{O} \rightarrow {n} \cdot \text{HOOC}(\text{CH}_2)_4\text{COOH} + {n} \cdot \text{H}_2\text{N}(\text{CH}_2)_6\text{NH}_2 \]

Confirming the Products

Verify the products for correctness: - Hydrolysis of benzoic amide delivers benzoic acid and methylamine as intended. - Hydrolysis of nylon-6,6 delivers the monomer units of adipic acid and hexamethylene diamine. Both results align with expectations for hydrolytic cleavage of amide bonds.

Key concepts

Amide

An amide is a functional group commonly found in organic chemistry. Amides are characterized by a carbonyl group (C=O) attached to a nitrogen atom. This structure plays a crucial role in the stability and functionality of many biological molecules and materials.
In hydrolysis, the amide bond is broken by water, producing a carboxylic acid and an amine. For example, the hydrolysis of the amide \(C_6H_5CONHCH_3\) involves water splitting the bond between the carbon atom of the carbonyl group and the nitrogen atom, forming benzoic acid \(C_6H_5COOH\) and methylamine \(CH_3NH_2\).

• Amides are pivotal in protein structures, linking amino acids in peptide bonds.
• Understanding amide hydrolysis is essential for polymer degradation processes.

Carboxylic Acid

Carboxylic acids are organic compounds characterized by the presence of a carboxyl group (COOH), which is highly reactive and an essential functional group in chemistry.
When amides undergo hydrolysis, they typically yield a carboxylic acid as one of the main products. For example, during the hydrolysis of the amide \(C_6H_5CONHCH_3\), benzoic acid is formed.

• Carboxylic acids are building blocks for many larger organic molecules.
• They are crucial in biochemical processes, such as the citric acid cycle.
• The acidity of carboxylic acids allows them to participate in a variety of chemical reactions.

Structural Formula

A structural formula is a graphic representation of a molecule that shows the arrangement of atoms and the bonds between them.
This type of formula gives more detail than a simple molecular formula, allowing us to understand how molecules like amides and carboxylic acids are formed or broken down. In the context of hydrolysis, using structural formulas helps us visualize the process and outcomes. For instance, the hydrolysis of \(C_6H_5CONHCH_3\) is clearly demonstrated by showing which bonds break and how atoms rearrange to form benzoic acid and methylamine.

• Structural formulas provide clarity in understanding complex reactions such as polymer degradation.
• They are essential tools in organic chemistry for predicting reaction products.

Polyamide

Polyamides are polymers that consist of repeating amide units, known for their high strength and durability. Commonly known polyamides include nylon, which is widely used in textiles and plastics.
The hydrolysis of polyamides, such as nylon-6,6, involves breaking the amide linkages. This process results in smaller molecules, like adipic acid and hexamethylene diamine, reflecting the original monomers used to create the polymer.

• Understanding polyamide chemistry is vital for recycling and materials science.
• They illustrate the application of amide chemistry in real-world materials.

Polymer Chemistry

Polymer chemistry is the study of large molecules made up of repeating units, or monomers, which have vast applications in everyday life.
Hydrolysis plays a crucial role in polymer chemistry, especially for recycling purposes. By breaking down polymers such as polyamides, researchers and industry professionals can achieve not only waste reduction but also recovery of original materials for reuse. For example, nylon-6,6 can be broken down into its components—adipic acid and hexamethylene diamine—through hydrolysis.

• Polymer chemistry bridges the gap between organic chemistry and material science.
• Innovations in polymer chemistry include developing biodegradable plastics and sustainable materials.