METHOD FOR PURIFYING CRUDE BIS--HYDROXYETHYL TEREPHTHALATE AND THE THUS PURIFIED BIS--HYDROXYETHYL TEREPHTHALATE

摘要

PROBLEM TO BE SOLVED: To provide a method for obtaining highly purified bis--hydroxyethyl terephthalate.;SOLUTION: This method for purifying bis--hydroxyethyl terephthalate comprises the following two steps: (1) crude bis--hydroxyethyl terephthalate containing a total of 50 ppm of (i) cations consisting of Na, Mg, Ca, Fe, Co, Zn, Ti, Sn Sb, Ge and P and (ii) anions consisting of halogens, NO2, NO3, PO4 and SO4 is put to crystallization and (2) the thus crystallized bis-- hydroxyethyl terephthalate is evaporated or distilled under reduced pressure.;COPYRIGHT: (C)2002,JPO