PROCESSES FOR THE PURIFICATION OF BIS(2-HYDROXYETHYL) TEREPHTHALATE

摘要

The invention aims at providing a process for recovering high-purity bis(2-hydroxylethyl) terephthalate (BHET) efficiently from an ethylene glycol (EG) solution containing crude BHET, particularly a depolymerization solution obtained by depolymerizing a polyester comprising polyethylene terephthalate (PET) as the main component with EG, while suppressing the formation of impurities such as diethylene glycol (DEG), DEG esters and oligomers. The invention relates to a process for the purification of BHET which comprises crystallizing the depolymerization solution under specified temperature conditions and subjecting the obtained mixture to solid-liquid separation, and to a process for the purification of BHET which comprises the evaporation step of evaporating low-boiling components from the depolymerization solution under specified conditions to thereby obtain a melt and the molecular distillation step of distilling the obtained melt under specified conditions and recovering a specific fraction.