Polyethylene Terephthalate Deconstruction Catalyzed by a Carbon‐Supported Single‐Site Molybdenum‐Dioxo Complex

Polyethylene terephthalate (PET) is selectively depolymerized by a carbon‐supported single‐site molybdenum‐dioxo catalyst to terephthalic acid (PTA) and ethylene. The solventless reactions are most efficient under 1 atmosphere of H2. The catalyst exhibits high stability and can be recycled multiple...

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Bibliographic Details
Published in:Angewandte Chemie (International ed.) 2020-11, Vol.59 (45), p.19857-19861
Main Authors: Kratish, Yosi, Li, Jiaqi, Liu, Shanfu, Gao, Yanshan, Marks, Tobin J.
Format: Article
Language:English
Subjects:
Benzoates
Carbon
Catalysts
Cleavage
Deconstruction
Depolymerization
heterogenous catalysis
Hydrogenolysis
Molybdenum
Polyethylene
Polyethylene terephthalate
polymers
Polypropylene
reaction mechanisms
Terephthalic acid
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Summary:Polyethylene terephthalate (PET) is selectively depolymerized by a carbon‐supported single‐site molybdenum‐dioxo catalyst to terephthalic acid (PTA) and ethylene. The solventless reactions are most efficient under 1 atmosphere of H2. The catalyst exhibits high stability and can be recycled multiple times without loss of activity. Waste beverage bottle PET or a PET + polypropylene (PP) mixture (simulating the bottle + cap) proceeds at 260 °C with complete PET deconstruction and quantitative PTA isolation. Mechanistic studies with a model diester, 1,2‐ethanediol dibenzoate, suggest the reaction proceeds by initial retro‐hydroalkoxylation/β‐C−O scission and subsequent hydrogenolysis of the vinyl benzoate intermediate. A carbon‐supported single‐site molybdenum‐dioxo catalyst, C/MoO2, catalyzes the hydrogenolytic deconstruction of polyethylene terephthalate (PET) to its monomers, terephthalic acid and ethylene, under 1 atm of H2. C/MoO2 can be recycled multiple times without loss of activity. Mechanistic studies suggest an initial β‐scission step, followed by hydrogenolysis of a vinyl benzoate intermediate.
ISSN:1433-7851
1521-3773
DOI:10.1002/anie.202007423