Question

Nylon, a polyamide, is produced from hexanediamine and asubstance \(X .\) This substance \(X\) is most probably \(a(n)\): a. amine. b. carboxylic acid. c. ketone d. alcohol.

Short answer

b. carboxylic acid.

Step-by-step solution

Understand the Problem

Nylon is a type of polyamide, which means it is formed through a polymerization reaction involving amines and another functional group. The exercise asks to identify the substance 'X' that reacts with hexanediamine to form nylon.

Identify Functional Groups Involved in Polyamides

Polyamides are typically formed through the reaction between amines (containing -NH2 groups) and carboxylic acids (containing -COOH groups). The two functional groups react to form amide bonds (-CONH-).

Analyze the Given Options

Evaluate each option: a. Amine: Amine reacts but isn’t suitable to form the polyamide on its own. b. Carboxylic acid: Carboxylic acid reacts with amines to form polyamides. c. Ketone: Ketones do not form polyamides with amines. d. Alcohol: Alcohols do not form the required amide bonds with amines.

Determine the Correct Answer

From the analysis, the substance 'X' should be a carboxylic acid (option b) to react with hexanediamine and form nylon.

Key concepts

Polyamide Synthesis

Polyamides are polymers that contain repeating amide bonds. To synthesize a polyamide, you need a molecule with amine groups and another with carboxylic acid groups. These groups react in a process called condensation polymerization. In the case of Nylon, it is synthesized from hexanediamine (which contains amine groups) and a carboxylic acid. This reaction releases a molecule of water for each bond formed, linking the monomers into long chains. The result is a strong and durable material used in textiles, plastic, and more.

Functional Groups

Functional groups are specific groups of atoms within molecules that have characteristic properties and chemical reactions.
In polyamide formation, the relevant functional groups are:

• Amines (-NH2): Found in compounds like hexanediamine, these groups are essential in forming amide bonds through a condensation reaction.
• Carboxylic Acids (-COOH): These groups react with amines to form amides, which are the building blocks of polyamides.

Knowing the functional groups involved helps in understanding and predicting the product of chemical reactions, like the formation of nylon.

Carboxylic Acid Reactions

Carboxylic acids are organic acids that contain a carboxyl group (-COOH).
In the formation of polyamides, they play a crucial role by reacting with amines to form amide bonds (-CONH-).
Here's how it works:

• The carboxyl group on the carboxylic acid reacts with the amine group on the amine.
• This results in the formation of an amide bond and the release of a water molecule, a type of condensation reaction.

This reaction is crucial in the synthesis of polyamides like nylon. It determines both the structure and the properties of the resulting polymer.

Amine Reactions

Amines are organic compounds derived from ammonia by the substitution of one or more hydrogen atoms with alkyl or aryl groups.
In the context of polyamide synthesis, amines are vital as they react with carboxylic acids to form amide bonds.
During the reaction:

• The nitrogen atom in the amine donates a pair of electrons to the carbon in the carboxyl group of the acid.
• This forms a new bond, resulting in a molecule with both amine and carboxylic acid components linked by an amide bond.

This type of reaction is fundamental in forming various polymers, including nylon, which exhibits high strength and elasticity due to these amide linkages.