Energy-saving separation of crude di:methyl terephthalate fraction under mild conditions

摘要

The process concerns the separation of a crude dimethyl terephthalate (DMT) fraction from a fraction rich in methyl para-toluate (p-TE) and a high-boiling residue fraction in the manufacture of DMT by catalytic oxidation of para-xylene (p-X) and p-TE and esterification of the reaction product with methanol (MeOH). Separation of the crude ester is carried out at 100-280 deg C and 50-500 mbar absolute in a unit with a dividing wall column or a distillation column preceded or followed by another column.