PET glycolysis optimization using ionic liquid [Bmin]ZnCl3 as catalyst and kinetic evaluation

Silva, Carlos Vinícius Guimarães; Filho, Eloi Alves da Silva; Uliana, Fabrício; Jesus, Luciana Fernanda Rangel de; Melo, Carlos Vital Paixão de; Barthus, Rosangela Cristina; Rodrigues, José G. A.; Vanini, Gabriela

doi:10.1590/0104-1428.00418

Cited by 17 publications

(7 citation statements)

References 23 publications

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“…On the other hand, BHET spectra (Figure 4b) displayed highly narrow peaks indicating the crystallinity and purity of the monomer obtained after depolymerization of PET. The characteristics of BHET peaks appeared at a respective region, which was well matched with the literature reports 9,25 . More importantly, the appearance of a new intense peak at 3450 cm −1 due to the presence of hydroxyl groups in the case of BHET proved the conversion of PET into its monomer, BHET.…”

Section: Resultssupporting

confidence: 88%

“…In most cases, glycolysis employs excess ethylene glycol as a reagent to break ester bonds of PET to obtain its monomer. The quality of the degradation product obtained by the glycolysis process is often much higher; as a result, it can be further reused while producing fine chemicals 9,10 . However, in the absence of the catalyst, the rate of glycolysis is very slow; hence ionic liquids‐based catalytic systems have emerged as an effective catalyst for the degradation of PET by being a green solvent with nonvolatile behavior, high thermal and chemical stability, and low inflammability 11,12 .…”

Section: Introductionmentioning

confidence: 99%

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Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Gayathri

Sheyara

Devassy

et al. 2022

J of Applied Polymer Sci

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Herein we have reported the effective use of palladium‐based systems which contain modified N‐Heterocyclic carbene (NHC) tagged with poly(N‐isopropylacrylamide) (PNIPAM) moiety as an organometallic catalyst. This report involves a comparative study between two catalysts, PNIPAM‐NHC‐Pd (II) complex (catalyst A) and PNIPAM‐NHC‐Pd (0) nanoparticles (catalyst B), to participate in the degradation of poly(ethylene terephthalate) (PET) into its monomer, bis(2‐hydroxyethyl terephthalate) (BHET) through glycolysis with ethylene glycol (EG). Glycolysis of the PET was carried out at different temperatures (170, 175, 180, 185, and 190°C) and times (6 and 24 h) where optimum results were obtained while glycolysis was performed at 180°C for 24 h using catalyst B. The investigation of the glycolysis product through NMR, ATR‐IR, TGA, and DSC proved the formation of BHET as the main product. To ensure the effective recycling of the PET and further value additions, the obtained glycolysis product, BHET was further transformed into its dibenzoylated derivative, bis(2‐([4‐Butoxy benzoyl]oxy)ethyl) terephthalate (BBET) by successive benzoylation using 4‐butoxybenzoyl chloride. The obtained BBET was used as an additive along with the commercial polyurethane‐based adhesive (CPU), and its effect on the properties of CPU was investigated using differential scanning calorimetry (DSC) studies.

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Section: Resultssupporting

confidence: 88%

Section: Introductionmentioning

confidence: 99%

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Gayathri

Sheyara

Devassy

et al. 2022

J of Applied Polymer Sci

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“…The melting point of unconverted PET residue was also measured and it was found that residue starts melting around 162 °C but melts completely around 168 °C corresponding to the dimer melting temperature range [ 38 ]. The melting point of BHET is in accordance as reported in various studies 109–110 [ 39 ], 111 [ 40 ] and 113.34 °C [ 41 ] via DSC-analysis. The melting point analysis is further supported by DSC analysis ( Figure S5 ) which shows that PET residue comprises only monomer and dimer peaks.…”

Section: Resultssupporting

confidence: 88%

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

2023

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Glycolysis of post-consumer polyethylene terephthalate (PET) waste is a promising chemical recycling technique, back to the monomer, bis(2-hydroxyethyl) terephthalate (BHET). This work presents sodium methoxide (MeONa) as a low-cost catalyst for this purpose. BHET product was confirmed by gas chromatography-mass spectrometry (GCMS), Nuclear Magnetic Resonance (NMR) Spectroscopy, melting point, and Differential Scanning Calorimetry (DSC). It was shown, not surprisingly, that PET conversion increases with the glycolysis temperature. At a fixed temperature of 190 °C, the response surface methodology (RSM) based on the Box-Behnken design was applied. Four independent factors, namely the molar ratio of PET: MeONa (50–150), the molar ratio of ethylene glycol to PET (EG: PET) (3–7), the reaction time (2–6 h), and the particle size (0.25–1 mm) were studied. Based on the experimental results, regression models as a function of significant process factors were obtained and evaluated by analysis of variance (ANOVA), to predict the depolymerization performance of MeONa in terms of PET conversion. Coefficient of determination, R2 of 95% indicated the adequacy for predicted model. Afterward, the regression model was validated and optimized within the design space with a prediction of 87% PET conversion at the optimum conditions demonstrating a deviation of less than 5% from predicted response. A van ‘t Hoff plot confirmed the endothermic nature of the depolymerization reaction. The ceiling temperature (TC = 160 °C) was calculated from Gibbs’ free energy. A kinetic study for the depolymerization reaction was performed and the activation energy for MeONa was estimated from the Arrhenius plot (EA = 130 kJ/mol). The catalytic depolymerization efficiency of MeONa was compared under similar conditions with widely studied zinc acetate and cobalt acetate. This study shows that MeONa’s performance, as a glycolysis catalyst is promising; in addition, it is much cheaper and environmentally more benign than heavy metal salts. These findings make a valuable contribution towards the chemical recycling of post-consumer PET waste to meet future recycling demands of a circular economy.

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“…Most of the homogenous catalysts (encompassing metal acetates [ 146 , 147 , 148 , 149 , 150 ], chlorides [ 151 , 152 ], alkoxides [ 46 ], hydroxides [ 153 ], carbonates [ 154 , 155 ], sulfates [ 156 ], and phosphates [ 157 ]) necessitate an additional unit operation in the chemical process, such as distillation. Zinc acetate (Zn(OAc) 2 ) has been widely employed as a catalyst for the glycolysis of PET, demonstrating its effectiveness for polyesters degradation (82 documents found on Scopus when we searched for “PET AND glycolysis AND zinc AND acetate”, March 2024).…”

Section: Glycolysis—a Way For Circular Horizonsmentioning

confidence: 99%

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

Enache,

Grecu,

Samoila

2024

Materials

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Plastic pollution has escalated into a critical global issue, with production soaring from 2 million metric tons in 1950 to 400.3 million metric tons in 2022. The packaging industry alone accounts for nearly 44% of this production, predominantly utilizing polyethylene terephthalate (PET). Alarmingly, over 90% of the approximately 1 million PET bottles sold every minute end up in landfills or oceans, where they can persist for centuries. This highlights the urgent need for sustainable management and recycling solutions to mitigate the environmental impact of PET waste. To better understand PET’s behavior and promote its management within a circular economy, we examined its chemical and physical properties, current strategies in the circular economy, and the most effective recycling methods available today. Advancing PET management within a circular economy framework by closing industrial loops has demonstrated benefits such as reduced landfill waste, minimized energy consumption, and conserved raw resources. To this end, we identified and examined various strategies based on R-imperatives (ranging from 3R to 10R), focusing on the latest approaches aimed at significantly reducing PET waste by 2040. Additionally, a comparison of PET recycling methods (including primary, secondary, tertiary, and quaternary recycling, along with the concepts of “zero-order” and biological recycling techniques) was envisaged. Particular attention was paid to the heterogeneous catalytic glycolysis, which stands out for its rapid reaction time (20–60 min), high monomer yields (>90%), ease of catalyst recovery and reuse, lower costs, and enhanced durability. Accordingly, the use of highly efficient oxide-based catalysts for PET glycolytic degradation is underscored as a promising solution for large-scale industrial applications.

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PET glycolysis optimization using ionic liquid [Bmin]ZnCl3 as catalyst and kinetic evaluation

Cited by 17 publications

References 23 publications

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Investigating the degradation of PET utilizing NHC‐based catalysts and effective reuse of the degradation product as an additive with polyurethane adhesive material

Optimization and Kinetic Evaluation for Glycolytic Depolymerization of Post-Consumer PET Waste with Sodium Methoxide

Polyethylene Terephthalate (PET) Recycled by Catalytic Glycolysis: A Bridge toward Circular Economy Principles

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