Patent ID: 7211193
Filing Date: 2007-05-01
Classification: C07C

Abstract:
1. A method of purifying bis(2-hydroxyethyl)terephthalate which comprises: (1) a crystallization step of cooling an ethylene glycol solution containing crude bis(2-hydroxyethyl)terephthalate from a temperature of at least saturation solubility to temperatures ranging from 15 to 30° C. and keeping the solution within the temperature range for 2 to 12 hours, and wherein the solution is obtained by decomposing post-consumer PET bottles by use of ethylene glycol, and the solution contains a solute in an amount of 5 to 40 wt % and 2-hydroxyethyl[2-(2-hydroxyethoxy)ethyl] terephthalate in an amount of 1 to 8 wt % based on all solutes, and (2) a solid-liquid separation step of subjecting a precipitate containing bis(2-hydroxyethyl)terephthalate as a main component to solid-liquid separation while keeping the precipitate within a temperature range of 15 to 30° C. so as to obtain a cake comprising bis(2-hydroxyethyl)terephthalate as a main component.