Q.How is terylene prepared ?

Terylene, the polyester fibre also known as Dacron or PET, is manufactured by condensing many molecules of ethylene glycol with terephthalic acid, catalysed and heated so that the two monomers link up repeatedly through ester bonds, releasing water at each step.

Terylene (polyethylene terephthalate, PET) is a condensation (step-growth) polymer prepared by heating a mixture of ethylene glycol and terephthalic acid (or, industrially, dimethyl terephthalate, which releases methanol instead of water) in the presence of a catalyst such as zinc acetate and antimony trioxide, at a high temperature (typically $420$–$460\ K$): $n\,HOCH_2CH_2OH + n\,HOOC-C_6H_4-COOH \xrightarrow[\text{Zn acetate/}Sb_2O_3]{\Delta} \left[-OCH_2CH_2-OOC-C_6H_4-CO-\right]_n + 2n\,H_2O$ The two monomers repeatedly undergo ester-forming condensation, eliminating a small molecule of water (or methanol, in the dimethyl ester route) at each linking step, building up the long-chain polyester. Terylene is widely us …