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Title: Subcritical CO2-H2O Hydrolysis of Polyethylene Terephthalate as a Sustainable Chemical Recycling Platform

Journal Article · · Green Chemistry
DOI:https://doi.org/10.1039/D3GC04576E· OSTI ID:2325039

The development of an efficient and environmentally sustainable chemical hydrolysis process for recycling waste plastics, based on green chemistry principles, is a key challenge. In this work, we investigated the role of subcritical CO2 on the hydrolysis of polyethylene terephthalate (PET) into terephthalic acid (TPA) at 180-200 degrees C for 10-100 min. The addition of CO2 into the reaction mixture led to the in situ formation of carbonic acid that helps to catalyze PET hydrolysis relative to hot compressed H2O (i.e. N2-H2O). The highest TPA yield of 85.0 +/- 1.3% was obtained at 200 degrees C, PET loading of 2.5 g PET in 20 mL H2O for 100 min, and 208 psi of initial CO2 pressure. In addition, the subcritical CO2-H2O system demonstrated high selectivity toward hydrolyzing PET in a mixture with polyethylene (PE) at 200 degrees C for 100 min, thus providing "molecular sorting" capabilities to the recycling process. The robustness of the process was also demonstrated by the ability to hydrolyze both colored Canada Dry and transparent Pure Life waste PET bottles into high yields of TPA (>86%) at 200 degrees C. In addition, subcritical CO2-H2O hydrolysis of colored PET bottles resulted in a white TPA product similar to that generated from transparent PET bottles. Overall, this work shows that, under optimized reaction conditions, subcritical CO2 can provide acid tunability to the reaction medium to favor waste PET hydrolysis for subsequent recycling.

Research Organization:
National Renewable Energy Laboratory (NREL), Golden, CO (United States)
Sponsoring Organization:
USDOE Office of Energy Efficiency and Renewable Energy (EERE), Energy Efficiency Office. Advanced Manufacturing and Materials Technologies Office (AMMTO); USDOE Office of Energy Efficiency and Renewable Energy (EERE), Transportation Office. Bioenergy Technologies Office; USDOE BOTTLE Consortium
DOE Contract Number:
AC36-08GO28308
OSTI ID:
2325039
Report Number(s):
NREL/JA-2800-89212; MainId:89991; UUID:671d37dc-ffc5-459b-b71d-e4272132949e; MainAdminId:72123
Journal Information:
Green Chemistry, Journal Name: Green Chemistry
Country of Publication:
United States
Language:
English

References (57)

Chemical recycling of waste plastics for new materials production journal June 2017
Pet Waste Management by Chemical Recycling: A Review journal September 2008
Chemical Recycling of Poly(ethylene terephthalate) journal April 1997
Kinetics of Hydrolysis of Poly(ethylene terephthalate) Powder in Sulfuric Acid by a Modified Shrinking-Core Model journal January 2001
Kinetics of Hydrolysis of PET Powder in Nitric Acid by a Modified Shrinking-Core Model journal February 1998
Chemical Recycling, Kinetics, and Thermodynamics of Poly (Ethylene Terephthalate) (PET) Waste Powder by Nitric Acid Hydrolysis journal January 2003
Depolymerization of PET into terephthalic acid in neutral media catalyzed by the ZSM-5 acidic catalyst journal October 2020
Chemolytic depolymerisation of PET: a review journal January 2021
Process optimization by NMR-assisted investigation of chemical pathways during depolymerization of PET in subcritical water journal January 2023
Neutral Hydrolysis of Post-Consumer Polyethylene Terephthalate Waste in Different Phases journal April 2023
From plant materials to ethanol by means of supercritical fluid technology journal October 2008
Ion product of water substance, 0–1000 °C, 1–10,000 bars New International Formulation and its background journal April 1981
Uncatalyzed Neutral Hydrolysis of Waste PET Bottles into Pure Terephthalic Acid journal April 2023
A kinetic study of the hydrolytic degradation of polyethylene terephthalate at high temperatures journal April 1993
Depolymerization of PET Bottle via Methanolysis and Hydrolysis book January 2019
Kinetics of neutral hydrolytic depolymerization of PET (polyethylene terephthalate) waste at higher temperature and autogenious pressures journal August 2008
Carbon Dioxide in Biomass Processing: Contributions to the Green Biorefinery Concept journal November 2014
CO2 utilization applied on converting of polyethylene terephthalate feedstock materials journal December 2023
Supercritical carbon dioxide as a green solvent for processing polymer melts: Processing aspects and applications journal January 2006
Supercritical CO2 foaming and shrinkage resistance of thermoplastic polyurethane/modified magnesium borate whisker composite journal March 2022
Chemical recycling of polyethylene in oxygen-enriched supercritical CO2 journal February 2022
Swelling and sorption in polymer–CO2 mixtures at elevated pressures journal December 1987
In situ FTIR micro-spectroscopy to investigate polymeric fibers under supercritical carbon dioxide: CO2 sorption and swelling measurements journal June 2014
Supercritical impregnation of polymers journal August 2003
Anin situ study of plasticization of polymers by high-pressure gases journal April 1998
Applications of vibrational spectroscopy to characterize poly(ethylene terephthalate) processed with supercritical CO2 journal April 1999
Effect of CO2 on crystallization kinetics of poly(ethylene terephthalate) journal February 2003
Crystallization of poly(ethylene terephthalate) induced by carbon dioxide sorption at elevated pressures journal March 1991
Carbon Dioxide Synergistic Enhancement of Supercritical Methanol on PET Depolymerization for Chemical Recovery journal May 2022
Tungsten-promoted titania as solid acid for catalytic hydrolysis of waste bottle PET in supercritical CO2 journal January 2016
Study of polyester degradation by sub/supercritical ethanol and enhancement of carbon dioxide journal March 2023
Catalytic Transformation of PET and CO2 into High‐Value Chemicals journal January 2022
Catalytic Fabric Recycling: Glycolysis of Blended PET with Carbon Dioxide and Ammonia journal July 2023
Reaction kinetics and mechanism of catalyzed hydrolysis of waste PET using solid acid catalyst in supercritical CO2 journal October 2014
Quantifying rate enhancements for acid catalysis in CO2‐enriched high‐temperature water journal December 2007
Integrated conversion of agroindustrial residue with high pressure CO 2 within the biorefinery concept journal January 2014
Insight into the high-pressure CO2 pre-treatment of sugarcane bagasse for a delivery of upgradable sugars journal May 2018
Effective Extraction of Lignin from Elephant Grass Using Imidazole and Its Effect on Enzymatic Saccharification To Produce Fermentable Sugars journal April 2017
A green and efficient approach to selective conversion of xylose and biomass hemicellulose into furfural in aqueous media using high-pressure CO 2 as a sustainable catalyst journal January 2016
Highly efficient and selective CO 2 -adjunctive dehydration of xylose to furfural in aqueous media with THF journal January 2016
High-solids biphasic CO2-H2O pretreatment of lignocellulosic biomass journal June 2010
Two-temperature stage biphasic CO2-H2O pretreatment of lignocellulosic biomass at high solid loadings journal January 2012
Producing concentrated solutions of monosaccharides using biphasic CO2–H2O mixtures journal January 2012
Comprehensive analysis of sugarcane bagasse steam explosion using autocatalysis and dilute acid hydrolysis (H3PO4 and H2SO4) at equivalent combined severity factors journal November 2018
Influence of Pretreatment Severity Factor and Hammett Acidity on Softwood Fractionation by an Acidic Protic Ionic Liquid journal January 2023
High-pressure carbon dioxide/water pre-treatment of sugarcane bagasse and elephant grass: Assessment of the effect of biomass composition on process efficiency journal January 2017
Enzymatic depolymerization of highly crystalline polyethylene terephthalate enabled in moist-solid reaction mixtures journal July 2021
Size Exclusion Chromatography book January 1999
Equilibrium melting parameters of poly(ethylene terephthalate) journal February 1978
Hydrolytic degradation of poly(ethylene terephthalate): Importance of chain scission versus crystallinity journal January 1991
Prediction of terephthalic acid yield in aqueous hydrolysis of polyethylene terephthalate journal April 2023
Solubility of Terephthalic Acid in Subcritical Water journal April 2012
Hydrolysis of waste polyethylene terephthalate catalyzed by easily recyclable terephthalic acid journal November 2021
The CO2-assisted autohydrolysis of wheat straw journal January 2014
Highly Efficient Solid‐State Hydrolysis of Waste Polyethylene Terephthalate by Mechanochemical Milling and Vapor‐Assisted Aging journal October 2020
A 1H and 13C n.m.r. study of the products from direct polyesterification of ethylene glycol and terephthalic acid journal January 1992
Unexpected efficiency of cyclic amidine catalysts in depolymerizing poly(ethylene terephthalate) journal January 2013

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