Method for producing high purity bis - (2-hydroxyethyl) terephthalate, recycled polyethylene terephthalate, decolorization solvent and method for purification of bis - (2-hydroxyethyl) terephthalate

摘要

Problem to be solved: to provide a method of producing a high purity bJet capable of conveniently producing a high purity bis - (2-hydroxyethyl) terephthalate (BHET) from a colored polyester waste.A method for producing high purity baet of the present invention isA depolymerization process for depolymerizing a colored polyester waste and obtaining a depolymerized solution containing a colored coarse baetA concentrated step of removing a low boiling point component contained in the depolymerization and concentrating BHETRecovery process for recovering BHET from coarse BHET and obtaining medium purity BHETThe middle purity BHET was crystallized in decolorization solvent.A crystallization separation process for obtaining a purified BHET by solid-liquid separation of a solvent component containing a crystal and a pigmentIt has a desolvent step for removing a residual solvent in the crystal of the purified baet to obtain a high purity blet.Diagram