Removal of dimethylterephthalate from a methanolysis vapor stream

摘要

A method of removing dimethyl terephthalate (DMT) from a vapor stream containing a mixture of dimethyl terephthalate (DMT), methylhydroxyethyl terephthalate (MHET), glycols and methanol comprising the steps of: (a) providing a distillation column that i) is held under an elevated pressure of 100 to 500 kPag and a temperature of at least 85C ii) has a plurality of distillation trays iii) has a methanol liquid sprays between the trays iv) has a main spray zone below the trays and v) has a liquid pool comprising methanol at the bottom of the column; (b) directing the vapor stream through an inlet nozzle into the distillation column above the liquid pool and below the main spray zone thereby forming a liquid solution comprised of vapor stream components; (c) directing the liquid solution away from the distillation column; and (d) concurrently recycling a portion of the liquid solution from (c) back into the distillation column as a spray in the column above the vapor stream inlet, thereby preventing build up of solid DMT on column surfaces.