Sodium Methoxide Catalyzed Depolymerization of Waste Polyethylene Terephthalate Under Microwave Irradiation

Mahmoud A. Mohsin, Mohamed A. Alnaqbi, Reneesh M. Busheer, Yousef Haik

Research output: Contribution to journalArticle

Abstract

Chemical recycling of polyethylene terephthalate (PET) to produce terephthalic acid (TPA) was studied using in situ hydrolysis with sodium methoxide in methanol and dimethyl sulfoxide (DMSO) as solvent under microwave irradiation. The microwave-assisted reaction was carried out at different temperatures, and reaction time between 5 to 30 min. High degrees of depolymerization were examined at temperature near 70°C at microwave power 300 W. The reaction was carried out in a sealed microwave reactor in which the time and temperature were controlled and recorded. The products were mainly monomers such as TPA and ethylene glycol (EG) which were isolated and purified for further analysis. Monomethyl terephthalate, dimethyl terephthalate, and terephthalic acid were formed initially then converted to TPA as a single monomer product. Purified, TPA was analyzed and identified by NMR, TGA, DSC and FTIR. It was observed that the reaction greatly depends on the amount of sodium methoxide, the volume of methanol and DMSO used, the reaction time, and temperature. Compared to conventional heating methods, the time needed to achieve complete degradation of PET was significantly reduced to 5 min by using microwave irradiation and sodium methoxide catalyst. This has led to substantial saving in energy and cost supporting the conclusion that this proposed recycling process is very beneficial for the recycling of PET wastes.

Original languageEnglish
Pages (from-to)41-48
Number of pages8
JournalCatalysis in Industry
Volume10
Issue number1
DOIs
Publication statusPublished - 1 Jan 2018

Fingerprint

Depolymerization
Polyethylene Terephthalates
Microwave irradiation
Polyethylene terephthalates
Methanol
Sodium
Acids
Recycling
Dimethyl sulfoxide
Microwaves
Dimethyl Sulfoxide
Monomers
Temperature
Ethylene Glycol
Ethylene glycol
Hydrolysis
Nuclear magnetic resonance
terephthalic acid
Heating
Degradation

Keywords

  • depolymerization
  • microwave irradiation
  • PET waste
  • poly(ethylene terephthalate)
  • sodium methoxide
  • terephthalic acid

ASJC Scopus subject areas

  • Catalysis

Cite this

Sodium Methoxide Catalyzed Depolymerization of Waste Polyethylene Terephthalate Under Microwave Irradiation. / Mohsin, Mahmoud A.; Alnaqbi, Mohamed A.; Busheer, Reneesh M.; Haik, Yousef.

In: Catalysis in Industry, Vol. 10, No. 1, 01.01.2018, p. 41-48.

Research output: Contribution to journalArticle

Mohsin, Mahmoud A. ; Alnaqbi, Mohamed A. ; Busheer, Reneesh M. ; Haik, Yousef. / Sodium Methoxide Catalyzed Depolymerization of Waste Polyethylene Terephthalate Under Microwave Irradiation. In: Catalysis in Industry. 2018 ; Vol. 10, No. 1. pp. 41-48.
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