Problem 5 - 43 Years JEE ADVANCED (1978-2020) + JEE MAIN Chapterwise & Topicwise Solved Papers Chemistry

Question

Poly- \(\square\)-hydroxybutyrate-co- \(\square\)-hydroxy valerate \((\mathrm{PHBV})\) is a copolymer of [Jan. 12, 2019 (I)] (a) 3-Hydroxybutanoic acid and 4-Hydroxypentanoic acid (b) 2-Hydroxybutanoic acid and 3-Hydroxypentanoic acid (c) 3-Hydroxybutanoic acid and 2-Hydroxypentanoic acid (d) 3-Hydroxybutanoic acid and 3-Hydroxypentanoic acid

Step-by-Step Solution

Answer

(d) 3-Hydroxybutanoic acid and 3-Hydroxypentanoic acid.

Step 1: Identify Key Components of PHBV

PHBV stands for poly(3-hydroxybutyrate-co-3-hydroxyvalerate). Key components are 3-hydroxybutyrate and 3-hydroxyvalerate.

Step 2: Translate to Corresponding Acids

Translate the components into their corresponding hydroxy acid forms. For 3-hydroxybutyrate, it corresponds to 3-hydroxybutanoic acid, and for 3-hydroxyvalerate, it corresponds to 3-hydroxypentanoic acid.

Step 3: Match with Provided Options

Examine the options provided: - (a) 3-Hydroxybutanoic acid and 4-Hydroxypentanoic acid - (b) 2-Hydroxybutanoic acid and 3-Hydroxypentanoic acid - (c) 3-Hydroxybutanoic acid and 2-Hydroxypentanoic acid - (d) 3-Hydroxybutanoic acid and 3-Hydroxypentanoic acid The correct match for PHBV is (d) 3-Hydroxybutanoic acid and 3-Hydroxypentanoic acid.

Key Concepts

PHBV

PHBV, or poly(3-hydroxybutyrate-co-3-hydroxyvalerate), is a fascinating copolymer that is increasingly gaining attention in the realm of materials science. This substance is a type of biopolymer, which means that it is derived from natural resources and is biodegradable. PHBV belongs to a family known as polyhydroxyalkanoates (PHAs), which are produced by microorganisms.

The composition of PHBV includes two main monomers: 3-hydroxybutanoic acid and 3-hydroxypentanoic acid, which polymerize together to form this unique copolymer. This combination of monomers gives PHBV certain desirable properties. For instance, it is known for being strong and having an excellent resistance to hot temperatures, making it suitable for various applications such as packaging materials and biomedical uses, like sutures.

• PHBV is biodegradable, making it environmentally friendly.
• It is utilized in applications ranging from medical to packaging.
• The polymer is derived from microorganisms, utilizing renewable resources.

Understanding the chemistry behind PHBV not only provides insights into sustainable material development but also paves the way for innovative applications in fields that demand eco-friendly solutions.

3-Hydroxybutanoic acid

3-Hydroxybutanoic acid, also known as β-hydroxybutyric acid, plays a crucial role in the formation of PHBV. It is one of the foundational monomers in this copolymer, contributing to the polymer's structure and properties. This compound is characterized by the presence of a hydroxyl (-OH) group attached to the third carbon of the butanoic acid chain, hence the name "3-hydroxy."

The synthesis of 3-hydroxybutanoic acid typically involves biological processes where certain bacteria ferment sugars in an oxygen-limited environment. From a biochemical perspective, it is noteworthy because it is also a ketone body produced during fatty acid metabolism, especially during keto diets or prolonged exercise.

• 3-Hydroxybutanoic acid is vital for the elasticity and resistance qualities of PHBV.
• This compound is biological in nature and a part of natural metabolic pathways.
• It serves as a structural component in other biodegradable polymers too.

By understanding its role and formation, insights are gained into not just polymer synthesis but also nutritional and metabolic processes in the body.

3-Hydroxypentanoic acid

3-Hydroxypentanoic acid is another critical component of the PHBV copolymer. This compound, sometimes referred to as valeric acid derivative, features a five-carbon chain with a hydroxyl group (-OH) bonded to the third carbon. Its inclusion in PHBV is essential because it alters the copolymer's physical properties.

Just like 3-hydroxybutanoic acid, 3-hydroxypentanoic acid is produced via microbiological methods. Specific strains of bacteria synthesize this compound when supplied with suitable substrates. It controls the polymer's flexibility and toughness, making PHBV suitable for specific applications such as flexible films and medical implements.

• It enhances PHBV's flexibility and durability.
• The compound is obtained through biological synthesis involving bacteria.
• It contributes to the variability and adaptability of PHBV in multiple uses.

Understanding how 3-hydroxypentanoic acid functions and integrates within PHBV helps in designing better materials that can meet various industrial and medical demands.