Problem 35 - A Complete Resource Book in Chemistry for JEE Main

Question

Which is used for the formation of nylon- \(6,6 ?\) (a) phthalic acid (b) sulphurous acid (c) sulphur hexafluoride (d) adipic acid

Step-by-Step Solution

Answer

Adipic acid (d) is used in forming nylon-6,6.

Step 1: Determine the Components of Nylon-6,6

Nylon-6,6 is a type of polyamide that is formed by the reaction of two specific organic compounds through a condensation polymerization process. The specific compounds used in the formation of nylon-6,6 are hexamethylenediamine and adipic acid.

Step 2: Analyze the Given Options

Review the options provided: (a) phthalic acid, (b) sulphurous acid, (c) sulphur hexafluoride, (d) adipic acid. Reflect on which of these compounds might contribute to the formation of nylon-6,6.

Step 3: Identify the Correct Acid for Nylon-6,6

Among the given options, adipic acid (option d) is the compound used in the formation of nylon-6,6 alongside hexamethylenediamine. Sulphurous acid, phthalic acid, and sulphur hexafluoride are not used in this synthesis.

Key Concepts

Condensation polymerization

Condensation polymerization is a key process used in creating polymers like Nylon 6,6. This process involves combining monomer units to form a polymer chain, accompanied by the release of a small molecule such as water. In the case of Nylon 6,6, the monomers are hexamethylenediamine and adipic acid. When these two monomers react, they form a repeating amide bond (also known as a peptide bond) and water is released as a by-product.
This type of reaction is essential for creating not just Nylon, but many other important polyamides as well.
Key characteristics of condensation polymerization include:

• The formation of a polymer by linking monomers with the simultaneous loss of small molecules
• The need for monomers with two functional groups, allowing them to form long chains
• It typically requires a catalyst and is conducted at high temperatures to facilitate the reaction

The simplicity and efficiency of this reaction type make it foundational in the creation of various synthetic polymers.

Hexamethylenediamine

Hexamethylenediamine is one of the two crucial components used in the synthesis of Nylon 6,6. It is an organic compound with the chemical formula \(C_6H_{16}N_2\), containing two amine groups. These amine groups make it highly reactive and suitable for forming amide bonds with carboxylic acid groups found in other monomers.
When hexamethylenediamine reacts with adipic acid, an amide bond forms, resulting in the long chains characteristic of polymers like Nylon 6,6.
Some important properties of hexamethylenediamine include:

• It is a colorless solid at room temperature
• Highly hydrophilic, which means it attracts water molecules
• Known for its stability and robust nature, making it ideal for polymer formation

Because of its reactivity and stability, hexamethylenediamine plays a pivotal role in the durability and performance of Nylon 6,6.

Adipic acid

Adipic acid is the second key ingredient in the formation of Nylon 6,6. It is an organic compound with the formula \(C_6H_{10}O_4\), comprising two carboxylic acid groups. These groups allow it to efficiently form amide bonds with hexamethylenediamine, creating the long polymer chains necessary for Nylon.
Adipic acid is well known within the chemistry field due to its:

• Colorless and crystalline solid form at room temperature
• High solubility in organic solvents
• Ability to yield water as a by-product when forming amide bonds

In the synthesis of Nylon 6,6, adipic acid's chemical properties ensure the completed polymer has high tensile strength and resilience, which are essential characteristics for materials used in textiles and industrial products. Adipic acid's pivotal role in the formation of Nylon 6,6 underscores its importance in producing high-performance materials.