Depolymerization of poly(ethylene terephthalate) wastes using ethanol and ethanol/water in supercritical conditions

Authors

  • Rubens E. N. De Castro,

    1. Universidade Estadual de Maringá, Departamento de Química, Grupo de Materiais Poliméricos e Compósitos, Av. Colombo, 5790–87020-900 Maringá, PR, Brazil
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  • Gentil J. Vidotti,

    1. Universidade Estadual de Maringá, Departamento de Química, Grupo de Materiais Poliméricos e Compósitos, Av. Colombo, 5790–87020-900 Maringá, PR, Brazil
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  • Adley F. Rubira,

    1. Universidade Estadual de Maringá, Departamento de Química, Grupo de Materiais Poliméricos e Compósitos, Av. Colombo, 5790–87020-900 Maringá, PR, Brazil
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  • Edvani C. Muniz

    Corresponding author
    1. Universidade Estadual de Maringá, Departamento de Química, Grupo de Materiais Poliméricos e Compósitos, Av. Colombo, 5790–87020-900 Maringá, PR, Brazil
    • Universidade Estadual de Maringá, Departamento de Química, Grupo de Materiais Poliméricos e Compósitos, Av. Colombo, 5790–87020-900 Maringá, PR, Brazil
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  • Patent application for the depolymerization process described in this work was filed with Instituto Nacional de Propriedade Industrial (INPI-Brazil) on July 16, 2004; protocol number PI0402976-3.

Abstract

Chemical recycling of poly(ethylene terephthalate) (PET) in supercritical ethanol has been investigated. In the presence of water, under supercritical conditions (temperature and pressure above 516 K and 6,384 kPa, respectively) excess ethanol reacts with PET to form diethyl terephthalate (DET) as the main product. A laboratory-made 0.1 L-batch reactor was used at 528 K under pressures from 7,600 and 11,600 kPa. After the required reaction times, the reaction products were analyzed by reverse phase high pressure liquid chromatography and nuclear magnetic resonance. It was found that PET is completely depolymerized into monomers in about 5 h. The influences of water, pressure, ethanol/PET weight ratio, PET sources, as well as depolymerization time were investigated. Maximum DET recovery yield was 98.5%. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 101: 2009–2016, 2006

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