Question

How is terylene prepared?

Hint:

Terylene is a polyester because the repeating units are joined by ester linkages (-COO-). If you replace terephthalic acid with phthalic acid (1,2-isomer), you get a different polymer called Glyptal.

Answer 1

Concept: Terylene (also known as Dacron) is a popular synthetic polyester fiber. It is prepared through condensation polymerization (specifically step-growth polymerization) between a diol and a dicarboxylic acid.
The two monomeric units required for the synthesis of terylene are: • Ethylene glycol (Ethane-1,2-diol): HO-CH₂-CH₂-OH • Terephthalic acid (Benzene-1,4-dicarboxylic acid): HOOC-C₆H₄-COOH
The polymerization is carried out at a high temperature (420 to 460 K) in the presence of a catalyst, typically a mixture of zinc acetate and antimony trioxide.
During the reaction, a molecule of water is eliminated between the hydroxyl group of the glycol and the carboxyl group of the acid, forming ester linkages. n HO-CH₂CH₂-OH + n HOOC-C₆H₄-COOH Δ, catalyst [--O-CH₂CH₂-O-CO-C₆H₄-CO--]ₙ + 2n H₂O
Properties and Uses:
Terylene is highly resistant to chemicals and moths, and it does not wrinkle easily. It is extensively used in making wash-and-wear fabrics, tire cords, and safety belts.