Pyrolysis versus hydrolysis behavior during steam decomposition of polyesters using<sup>18</sup>O-labeled steam

Kumagai, Seiji; Morohoshi, Yuto; Grause, Guido; Kameda, Tomohito; Yoshioka, Toshiaki

doi:10.1039/c5ra08577b

Cited by 27 publications

(16 citation statements)

References 63 publications

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“…Fragments of diethylphosphinate can also be found at 850 and 1018 cm −1 due to the presence of AlPi within the material mixture. reported to increase with decreasing decomposition temperature [33]. We conclude that the release of water by boehmite evolved the hydrolysis of PBT from a minor to one of the main decomposition pathways in the beginning of decomposition.…”

Section: Gas Analysismentioning

confidence: 64%

“…The release of water by boehmite at the beginning of pyrolysis enhances the hydrolysis and, thus, the formation of THF. The contribution of hydrolysis to the decomposition of PBT is reported to increase with decreasing decomposition temperature [33]. We conclude that the release of water by boehmite evolved the hydrolysis of PBT from a minor to one of the main decomposition pathways in the beginning of decomposition.…”

Section: Gas Analysismentioning

confidence: 70%

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Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

et al. 2020

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Aluminum tris-(diethylphosphinate) (AlPi) is known to have an efficient flame-retardant effect when used in poly(butadiene terephthalates) (PBT). Additionally, better flame-retardant effects can be achieved through the partial substitution of AlPi by boehmite in multi-component systems, which have been shown to be an effective synergist due to cooling effects and residue formation. Although the potential of beneficial effects is generally well known, the influence of particle sizes and behavior in synergistic compositions are still unknown. Within this paper, it is shown that the synergistic effects in flammability measured by limiting oxygen index (LOI) can vary depending on the particle size distribution used in PBT. In conducting thermogravimetric analysis (TGA) measurements, it was observed that smaller boehmite particles result in slightly increased char yields, most probably due to increased reactivity of the metal oxides formed, and they react slightly earlier than larger boehmite particles. This leads to an earlier release of water into the system enhancing the hydrolysis of PBT. Supported by Fourier transformation infrared spectroscopy (FTIR), we propose that the later reactions of the larger boehmite particles decrease the portion of highly flammable tetrahydrofuran in the gas phase within early burning stages. Therefore, the LOI index increased by 4 vol.% when lager boehmite particles were used for the synergistic mixture.

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Section: Gas Analysismentioning

confidence: 64%

Section: Gas Analysismentioning

confidence: 70%

Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

et al. 2020

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“…Table 3 lists the value of the reverse regression coefficient for model fitting, (R Model ), for the best three-fitting models for each condition. The experimental error of the equipment used was calculated to be approximately R Model = ±0.03, suggesting that the difference in R Model of 0.1 was within the range of error [21]. However, as the values of R Model determined under the same conditions were similar, irrespective of the presence and absence of an experimental error, the order of how probable the three best-fitting models was probably not important.…”

Section: Kinetic Analyses Of Pi Decomposition In Absence and Presencementioning

confidence: 98%

“…It was assumed that the k app value in the absence of steam was equal to the k app value for pyrolysis (i.e., k app(pyrolysis) = k app(withou steam) ). On the other hand, the increase in k app when steam was added was assumed to be equal to the k app value corresponding to hydrolysis (i.e., k app(hydrolysis) = k app(wit steam) − k app(withoutsteam) ) [21]. Thus, the selectivities of the hydrolysis and pyrolysis processes could be expressed as follows: k app(withsteam) × 100% (7) where S H is the selectivity of hydrolysis, S P is the selectivity of pyrolysis, k app(withoutsteam) is the k app value determined in the absence of steam, and k app(withsteam) is the k app value determined in the presence of steam.…”

Section: Kinetic Analyses Of Pi Decomposition In Absence and Presencementioning

confidence: 99%

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Pyrolysis and hydrolysis behaviors during steam pyrolysis of polyimide

Kumagai

Hosaka

Kameda

et al. 2016

Journal of Analytical and Applied Pyrolysis

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PETpyrolysis and hydrolysis mechanism in the fixed pyrolyzer

Song

Huo

et al. 2023

Can J Chem Eng

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In the conventional polyethylene terephthalate (PET) pyrolysis process, the formation of char by excessive pyrolysis is mainly due to the dehydration mechanism, so water is considered an auxiliary agent that can effectively inhibit excessive pyrolysis. The preparation of terephthalic acid (TPA) by steam‐assisted pyrolysis of PET is an effective method to achieve closed‐loop recycling of waste PET. To ensure that the reaction is mild enough to reduce excessive cracking products such as char and benzoic acid and thus increase the yield of TPA, it is critical to reduce the reaction rate while maintaining a sufficient excess steam coefficient. Under the optimal operating conditions, when the temperature rise rate was 0.5 °C min−1 and the excess steam coefficient was 150, the yield of TPA was 72.5 wt.%, and the purity was 85.5%. Noticeably, the steam‐assisted pyrolysis system is a heterogeneous reaction system whose reaction mechanism is different from the conventional hydrolysis and pyrolysis reactions and has a unique reaction path. The mechanistic study indicates that, in addition to the thermal cracking of PET molecules occurring in conventional pyrolysis, hydroxyl attack and transfer, and supplementation of benzene ring hydrogen also occur between water and intermediate molecules. Meanwhile, it has also been proven that the intermolecular hydrogen transfer between intermediate molecules and water molecules is the key to reduce the intensity of the reaction and inhibit the formation of char. This discovery illustrates the mechanism of the reaction between water and PET in the steam‐assisted pyrolysis process in the fixed pyrolyzer and justifies the distinction between it and the pyrolysis and hydrolysis processes of PET. It provides a theoretical basis for optimizing the pyrolysis process of PET, which is essential for the industrialization of TPA preparation from PET steam‐assisted pyrolysis.

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Pyrolysis versus hydrolysis behavior during steam decomposition of polyesters using¹⁸O-labeled steam

Abstract: A method was developed to distinguish between hydrolysis and pyrolysis pathways in the steam degradation of various polyesters. Selectivity was shown to be strongly influenced by the polyester structure.

Cited by 27 publications

References 63 publications

Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

Pyrolysis and hydrolysis behaviors during steam pyrolysis of polyimide

PETpyrolysis and hydrolysis mechanism in the fixed pyrolyzer

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Pyrolysis versus hydrolysis behavior during steam decomposition of polyesters using18O-labeled steam

Abstract: A method was developed to distinguish between hydrolysis and pyrolysis pathways in the steam degradation of various polyesters. Selectivity was shown to be strongly influenced by the polyester structure.

Cited by 27 publications

References 63 publications

Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

Particle Size Related Effects of Multi-Component Flame-Retardant Systems in poly(butadiene terephthalate)

Pyrolysis and hydrolysis behaviors during steam pyrolysis of polyimide

PETpyrolysis and hydrolysis mechanism in the fixed pyrolyzer

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Product

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Pyrolysis versus hydrolysis behavior during steam decomposition of polyesters using¹⁸O-labeled steam