Improved method of depolymerization of polyethylene terephthalate

The present invention relates to a method of depolymerization of polyethylene terephthalate (= "PET"), in which PET is converted to bis(2-hydroxyethyl) terephthalate (= "BHET") in a mixture with glycol and electrolytically produced alkali metal alkoxide, especially lithium alkoxi...

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Bibliographische Detailangaben
Hauptverfasser:	ZANDER, CHRISTIAN, REINSBERG, PHILIP HEINRICH, BLUM, ADRIAN, RUWWE, JOHANNES
Format:	Patent
Sprache:	chi ; eng
Schlagworte:	AFTER-TREATMENT NOT COVERED BY SUBCLASSES C08B, C08C, C08F,C08G CHEMISTRY COMPOSITIONS BASED THEREON GENERAL PROCESSES OF COMPOUNDING METALLURGY ORGANIC MACROMOLECULAR COMPOUNDS THEIR PREPARATION OR CHEMICAL WORKING-UP WORKING-UP
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Beschreibung
Zusammenfassung:	The present invention relates to a method of depolymerization of polyethylene terephthalate (= "PET"), in which PET is converted to bis(2-hydroxyethyl) terephthalate (= "BHET") in a mixture with glycol and electrolytically produced alkali metal alkoxide, especially lithium alkoxide, sodium alkoxide or potassium alkoxide. It is a feature of the method according to the invention that there is a particularly high proportion of BHET among the cleavage products, based on the proportion of the unwanted mono(2-hydroxyethyl) terephthalate (= "MHET") and terephthalate (= "TS") cleavage products. As a result, the method according to the invention affords a high yield of BHET, which can be used directly for new production of PET. The present invention thus also relates to a method of recycling PET, in which the BHET obtained in the method of depolymerization of PET, optionally after further purification, is polymerized again to give PET.