In the manufacture of polyethylene terephthalate (PET), dimethyl terephthalate is transesterified, or terephthalic acid is esterified, with an excess of ethylene glycol at 100-150°C and 10-70 bar in the presence of Cu, Co, or Zn acetate catalysts. The intermediate - bis(2-hydroxyethyl) terephthalate - is then poly-condensed at a higher temperature (150-270 °C) under vacuum and usually with a catalyst, e.g., Sb₂O₃; ethylene glycol is removed by distillation during thc reaction:

The resulting polyester melts are either spun directly or - as with the majority of manufacturers - cooled, granulated, and spun separately.