The Depolymerization of Poly(ethylene terephthalate) (PET) Using N-Heterocyclic Carbenes from Ionic Liquids
2010; American Chemical Society; Volume: 87; Issue: 5 Linguagem: Inglês
10.1021/ed800152c
ISSN1938-1328
AutoresNahrain E. Kamber, Yasuhito Tsujii, Kate Keets, Robert M. Waymouth, Russell C. Pratt, G.W. Nyce, James L. Hedrick,
Tópico(s)Carbon dioxide utilization in catalysis
ResumoThe depolymerization of the plastic polyethylene terephthalate (PET or PETE) is described in this laboratory procedure. The transesterification reaction used to depolymerize PET employs a highly efficient N-heterocyclic carbene catalyst derived from a commercially available imidazolium ionic liquid. N-heterocyclic carbenes are potent nucleophilic organic catalysts that provide an alternative to traditional metal alkoxide depolymerization catalysts. Deprotonation of the imidazolium generates an N-heterocyclic carbene, which catalyzed the glycolysis of PET in 1 h at atmospheric pressure in refluxing anhydrous tetrahydrofuran to afford bis(2-hydroxyethyl) terephthalate (BHET). BHET is characterized by NMR and IR spectroscopy and melting point determination. This laboratory is designed for individual student work where each student depolymerizes PET prepared from a common water bottle or other source. This experiment is well suited for an introductory organic chemistry laboratory course or a polymer chemistry laboratory course.
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