Reaction Network and Kinetics Model for Neutral Hydrolysis of Poly(ethylene terephthalate)

Industrial & Engineering Chemistry Research · 2026-02-27

We present a reaction network and kinetic model that describes the hydrolytic depolymerization of poly-(ethylene terephthalate) (PET) in water with neutral pH. The network comprises seven reaction pathways. It includes autocatalysis of PET depolymerization by terephthalic acid (TPA) and the generation of monohydroxyethyl terephthalate, bis-(2-hydroxyethyl) terephthalate, benzoic acid, and decomposition products of TPA and ethylene glycol as byproducts. The model can handle PET hydrolysis in the solid state and in the molten state. Parameter estimation was performed by fitting the model to product concentrations from literature for PET hydrolysis over a wide range of times (15 s to 25 h) and nominal reaction temperatures (170-570 °C). The model fits the entire set of experimental concentrations with a mean absolute error of 0.023 M. It also demonstrated the ability to predict product yields from many published studies. The highest TPA yield predicted by the model is 94%, obtained from hydrolysis at 450 °C (instantaneous heating) after a 20 s batch holding time. TPA yields of 100% were not achievable in the model because of TPA decomposition pathways and equilibrium reactions involving byproducts.

Driving Hydrolysis and Acetolysis of Poly(ethylene terephthalate) (PET) by Microwave and Thermal Energy Inputs: A Comparative Study

ACS Omega · 2026-02-23

This study compares microwave and conventional thermal energy inputs for the hydrolysis and acetolysis of both virgin and postconsumer poly-(ethylene terephthalate) (PET). Reaction conditions in these experiments range from 200 to 300 °C and from 5 to 90 min. In no instances did the yields of terephthalic acid monomer or incompletely depolymerized PET demonstrate statistically significant or practically significant differences with these two different energy inputs. For fixed reaction conditions, yields of terephthalic acid were comparable from both methods, regardless of whether the reaction medium was water, acetic acid, or a mixture of the two. The visual appearance of the unreacted plastic was likewise the same for microwave and conventional thermal energy inputs when using identical solvents. These results suggest that the bulk fluid temperature is the controlling factor for PET depolymerization in a homogeneous fluid phase of water and/or acetic acid with no added catalyst. The reacting system responds similarly whether the heating is via microwave irradiation or via conduction across the reactor wall.

Modafinil Synthesis Using an Eosin Y‐photocatalytic Gel Formed by Autocatalyzed Thiol‐Ene Crosslinking

Macromolecular Chemistry and Physics · 2025-02-20

Abstract Utilizing visible wavelength photons to drive chemical transformations in photocatalysis has become increasingly popular due to the promise of sustainability, safety, and modularity. Heterogeneous photocatalysis further allows for simplified separation and reuse of photocatalysts from reaction systems. Described herein is a proof‐of‐concept for a heterogeneous catalysis platform based on an Eosin Y photocatalyst network (EY‐gel) formed by an autocatalyzed thiol‐ene crosslinking reaction. The Eosin Y photocatalyst is modified with an acrylate handle, allowing for both catalysis of and participation in the thiol‐ene crosslinking reaction, thus incorporating the catalyst into the gel framework. The produced EY‐gel takes the form of micron‐sized spherical particles due to the use of a relative non‐solvent for the gel components during the crosslinking reaction, allowing for collection through simple filtration. The EY‐gel is shown to be effective for the synthesis of the narcolepsy drug Modafinil via the oxidation of 2‐[(diphenylmethyl)thio]acetamide, and also shows modest recyclability over multiple use cycles.

Why Mental Health Literacy Can Improve STEM

Angewandte Chemie · 2025-04-01

Abstract In recent years, an increasing number of articles have outlined the mental health crisis in academia. Despite its widely appreciated significance, most of the related research is published in journals focusing on education, social science, psychology, or psychiatry. Despite stakeholders in science, technology, engineering, and mathematics (STEM) being disproportionately affected, they are often left in the dark about important findings unless they seek out relevant information themselves. This contribution attempts to spark interdisciplinary discussion between psychology, psychiatry, and STEM by highlighting relevant research, advocating for increased knowledge on mental health, and elaborating on what benefits improved mental health literacy could have for both the individual and the academic system in its entirety.

Correction: Acid catalyst screening for hydrolysis of post-consumer PET waste and exploration of acidolysis

Green Chemistry · 2025-01-01 · 4 citations

Correction for ‘Acid catalyst screening for hydrolysis of post-consumer PET waste and exploration of acidolysis’ by Patrícia Pereira et al. , Green Chem. , 2024, 26 , 1964–1974, https://doi.org/10.1039/D3GC03906D.

Understanding PET Hydrolysis via Reactive Molecular Dynamics Simulation and Experimental Investigation

The Journal of Physical Chemistry B · 2025-06-23 · 10 citations

Polyethylene terephthalate (PET), a widely used polymer in packaging applications, has posed significant environmental challenges due to its resistance to environmental degradation. Chemical recycling via hydrolysis offers a circular solution by breaking PET down into its monomers, terephthalic acid and ethylene glycol, which can then be repolymerized into new PET. Despite its promise, the detailed pathways of PET hydrolysis─particularly the interplay between hydrolysis and thermal degradation─remain a topic of scientific debate. We combine reactive molecular dynamics (MD) simulations with experimental studies to elucidate key reaction pathways, intermediate species, and the temperature-dependent evolution of degradation products. Molecular dynamics simulations offer detailed insights into molecular motions and interactions that are often elusive in experimental setups, thus enhancing our understanding of the complex dynamics at play during PET decomposition. By systematically examining bond dissociation, intermediate species, and product formation at various temperatures, this study elucidates how hydrolysis and thermal degradation pathways evolve and interact. Furthermore, a severity index approach is employed to directly compare TPA yields from simulations with corresponding experimental data.

Physical aging and evolution of mechanical properties of additively manufactured polyethylene terephthalate glycol

RSC Applied Polymers · 2025-01-01 · 8 citations

Copolymer composition in PETG affects the impact of its physical aging on mechanical properties, which can influence the lifetime of additively manufactured durable plastic goods.

Why Mental Health Literacy Can Improve STEM

Angewandte Chemie International Edition · 2025-04-01 · 2 citations

In recent years, an increasing number of articles have outlined the mental health crisis in academia. Despite its widely appreciated significance, most of the related research is published in journals focusing on education, social science, psychology, or psychiatry. Despite stakeholders in science, technology, engineering, and mathematics (STEM) being disproportionately affected, they are often left in the dark about important findings unless they seek out relevant information themselves. This contribution attempts to spark interdisciplinary discussion between psychology, psychiatry, and STEM by highlighting relevant research, advocating for increased knowledge on mental health, and elaborating on what benefits improved mental health literacy could have for both the individual and the academic system in its entirety.

Influence of Metal Salts on the Hydrolysis of Postconsumer Poly(ethylene Terephthalate)

ACS ES&T Engineering · 2025-02-12 · 5 citations

This study reveals the effects of 23 metal salts on the hydrolysis of postconsumer poly(ethylene terephthalate) (PET). Isothermal reactions were conducted at 200 °C for 2 h and with a 1/10 (w/w) loading of PET and water. Terephthalic acid (TPA) yields of at least 80% were obtained with indium and ytterbium triflates, zinc iodide, potassium and sodium carbonates, potassium phosphate, and sodium bicarbonate. Without additives, the TPA yield was less than 10%, suggesting that these salts are potential candidates to improve the chemical recycling of PET. We expect complete catalytic depolymerization of PET to be available at longer times or higher temperatures. Reuse of zinc acetate solution for sequential hydrolysis experiments consistently gave high TPA yields for six cycles. We used experimental dataset and machine learning to determine that TPA yields and PET conversion were primarily influenced by the mass ratio of metal salt to PET, Lewis acidity, solution ionic strength, and pH. The catalytic effect of some metal triflates first increased with increasing Lewis acidity but peaked and declined as the Lewis acidity increased further. This suggests that higher Lewis acidity not only increases the intrinsic rate of hydrolysis but also increases the strength of the solvation shell around the catalyst, thereby hindering its access to the ester bonds in PET.

The Influence of Irradiation Wavelength on the Growth of Polymer Brushes by <scp>SI</scp> ‐ <scp>PET</scp> ‐ <scp>RAFT</scp> Polymerization

Journal of Polymer Science · 2025-02-22 · 4 citations

ABSTRACT An effective method to produce well‐defined polymer brushes with high spatial, temporal, and sequence control is to employ a photoredox catalyst in photo‐mediated polymerization. Generally, the excitation wavelength is chosen as the absorption maximum of the photocatalyst, however, it is not clear if that corresponds to the best photochemical activity for producing polymer brushes. Herein, we systematically examine wavelength‐by‐wavelength resolved polymer brush growth using surface‐initiated photoinduced electron transfer‐reversible addition‐fragmentation chain transfer polymerization (SI‐PET‐RAFT), of four monomer types. The absorption spectra of the water‐soluble photocatalyst (ZnTPPS 4 4− ) and the brush growth at each irradiation wavelength were examined as photochemical activity plots. Our results show a striking disparity between the absorbance of the photoredox catalyst and the maximum brush height. Moreover, the photochemical activity with wavelength was highly dependent on the nature of the monomer used. In addition to displaying a strong wavelength selectivity, a characteristic red‐shift in the brush height relative to the lowest possible energy transition of the photocatalyst's absorbance spectrum was observed. We anticipate this work will better inform on wavelength choice for SI‐PET‐RAFT polymerization of polymer brushes.