POLYMER DEGRADATION AND STABILITY
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2022
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IF 5.204
Zhiqiang Jiang,Dongxia Yan,Jiayu Xin,Fei Li,Mengquan Guo,Qing Zhou,Junli Xu,Yufeng Hu,Xingmei Lu
The methanolysis of polyethylene terephthalate (PET) was investigated using poly(ionic liquid)s (PILs) synthesized with 1-vinyl-3-ethylimidazole acetates ([VEIm]Ac) and acrylic acid metal salts, and the activities of the PILs were screened. The effects of reaction temperature, reaction time, methanol amount, catalyst amount and PET sources on the methanolysis of PET were investigated using the optimized catalyst PIL-Zn 2+ . Under the optimal conditions the conversion of PET was 100% and the yield of dimethyl terephthalate (DMT) was 89.1%. In addition, the catalyst has very good applicability for methanolysis of different PET raw materials. More importantly, the PIL-Zn 2+ catalyst could be recycled by simple filtration after the reaction, and could be reused six times without significant decrease in PET conversion and DMT yield. The catalysts were analyzed by TGA, FT-IR, XRD and ICP before and after recycling, the results showed no change in the structure of the catalyst, reflecting the good stability of the catalyst. The reaction kinetics of PIL-Zn 2+ was first-order with an activation energy of 107.6 kJ/mol. This work mainly provides a way to design efficient, stable and recyclable catalysts for PET methanolysis.
研究领域:
化学工程
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
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2022
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IF 16.744
Pengtao Fang,Xingmei Lu,Qing Zhou,Dongxia Yan,Jiayu Xin,Junli Xu,Chunyan Shi,Yongquan Zhou,Shuqian Xia
Controlled degradation of macromolecules or natural macromolecules is important for their subsequent utilization. Normally, it is easier to degrade them to monomers than to oligomers in designated molecular weight range, the controlled degradation is much difficult to achieve and has been challenge for the utilization of macromolecules. Here, we proposed a strategy for simultaneous degradation of the inner and outer layers of PET , which avoid the degradation of polymers from the outside to the inside and achieved the controlled degradation. Under high temperature and micro-pressure conditions, PET is transformed from dense to flocculent structure by the swelling effect, which satisfies the need for simultaneous degradation of the inner and outer layers. In addition, a stable “Dawson” type Polyoxometalates (POMs) α 2 -K 8 P 2 W 17 O 61 X(H 2 O)‧16H 2 O (X = Zn, Mn, Co, Ni, Cu) with limited number of catalytic activity center was synthesized and applied to PET alcoholysis to obtain oligomer with given molecular weight range. Under the optimal conditions, PET: EG: POM catalyst = 1.0: 4.0: 0.02 (wt%), 240 °C, 10 min, PET was completely degraded and obtained the oligomer products (Mn < 2000 g/mol) with 72.1 % yield. By investigating the mechanism of the controlled alcoholysis, the formation of flocculent PET was be the key factor in achieving controlled degradation; hydrogen bonding and coordination of POMs are the key interactions to achieve rapid alcoholysis. Finally, oligomers were applied in the preparation of PET-PLA copolymers to follow sustainable route. The incorporation of bio-based polymers demonstrates better inclusiveness to the environment and contributes to harmonious development.
研究领域:
材料科学
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环境科学
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高分子化学
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DOI
高影响因子
NEW JOURNAL OF CHEMISTRY
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2023
·Vol. 47
·期 31
·14646-14655
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IF 3.3
Ruiyang Wen,Guoliang Shen,Jinmiao Zhai,Linghui Meng,Yunlong Bai
Acetylacetone titanium oxide (TiO(acac)2) was synthesized from acetylacetone and isopropyl titanate via a one-pot method. The catalyst's structure and morphology were characterized and analyzed using FT-IR, UV–vis, XRD, SEM, and laser particle size analysis. The prepared acetylacetone titanium oxide was used for the alcoholysis reaction of polyethylene terephthalate (PET), and the yield of bis(hydroxyethyl) terephthalate (BHET) obtained from the alcoholysis reaction was taken as the index. The optimal conditions for the alcoholysis reaction were determined using response surface methodology: 3 g of PET, a catalyst dosage of 0.467%, a temperature of 200.5 °C, a time of 3.77 h, and 13.50 mL of ethylene glycol, with a BHET yield of 96.41%. The model had good reliability. Finally, the reaction mechanism was speculated, and the catalyst was compared with other catalysts. The TiO(acac)2 catalyst has a good application prospect.
研究领域:
化学工程
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材料科学
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催化反应
✓ 已验证
DOI
高影响因子
RSC Sustainability
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2025
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IF 4.9
ZIXIAN JIA,JIE ZHANG,LIN GAO,LIJIAO QIN,HAOCHENG SUN,JIAXING CHEN,Jian-Zhong Yin
The chemical recycling of polyethylene terephthalate (PET) via glycolysis is a promising route for recovering the monomer bis(2-hydroxyethyl) terephthalate (BHET), which can be used for virgin-grade PET production. However, the influence of water—an inevitable impurity and potential byproduct—on this process is complex and not fully elucidated. This study systematically investigates the effect of water content (0–22.2 vol%) on PET glycolysis using selected heterogeneous catalysts (ZnO, Mn₂O₃) and homogeneous catalysts (zinc acetate (ZnAc₂), 1,5,7-triazabicyclo[4.4.0]dec-5-ene (TBD), and 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU)). Product distribution and reaction kinetics were quantified by HPLC and in-situ IR spectroscopy, respectively.The heterogeneous catalysts (ZnO, Mn₂O₃) and homogeneous ZnAc₂ maintained high PET conversion (>95%) even at elevated water concentrations. Nevertheless, the BHET yield and selectivity for these systems decreased significantly due to a competing hydrolytic side reaction, promoted by water, which yields terephthalic acid (TPA). Notably, ZnAc₂ exhibited a more rapid decline in BHET selectivity compared to ZnO. Conversely, the organic base catalysts TBD and DBU experienced complete deactivation in the presence of water, resulting in a drastic reduction in both PET conversion and BHET yield, with DBU showing greater susceptibility. In-situ IR experiments corroborated that the deactivation mechanism for TBD involves protonation by water. These results emphasize that water's influence is a function of the catalyst's chemical nature, modulating product selectivity for metal-based systems while causing the deactivation of organic bases. Understanding these divergent effects is critical for the optimization of industrial PET glycolysis and the rational design of water-tolerant catalytic systems.
研究领域:
高分子化学
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催化化学
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化学回收
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反应工程
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环境化学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
POLYMER DEGRADATION AND STABILITY
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2021
·
IF 5.03
Zishuai Wang,Yaoqiang Wang,Shengnan Xu,Yu Jin,Zequn Tang,Gang Xiao,Haijia Su
Glycolysis of poly (ethylene terephthalate) (PET) is a promising way to recycle waste PET and produce bis-(2-hydroxyl ethyl) terephthalate (BHET), the monomer of PET. However, traditional catalysts will cause environment pollution and economic burden. In this work, based on the green and low-cost graphitic carbon nitride colloid, we developed a pseudo-homogeneous system for PET glycolysis, and poly (bisphenol A carbonate) (BPA-PC) and polylactic acid (PLA) methanolysis. Using this system, 100% conversion of PET and 80.30% yield of BHET were achieved, and the reaction time was 2-8 times shorter than that of other metal-based catalysis systems. Catalyst and ethylene glycol were reused five times directly preserving their activity. Furthermore, the degradation of real commercial plastics has also been achieved. According to FT-IR, XPS, and 1 H NMR characterization results, the nucleophilic attack ability of ethylene glycol and electrophilicity of the PET carbonyl's carbon are enhanced by the formation of hydrogen bond between ethylene glycol, PET and catalyst.
研究领域:
材料科学
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化学工程
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环境科学
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催化
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高分子化学
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回收技术
✓ 已验证
产品关联
DOI
高影响因子
GREEN CHEMISTRY
·
2023
·Vol. 25
·期 17
·6901-6913
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IF 9.8
Ling-Xia Yun,Yan Wei,Qian Sun,Yu-Ting Li,Bin Zhang,Hang-Tian Zhang,Zhi-Gang Shen,Jie-Xin Wang
Polyethylene terephthalate (PET), as the most widely utilized polyester, causes global environmental problems due to its massive and durable accumulation in natural environments. The glycolysis of PET is an attractive alternative to mechanical recycling, but there remains a strong demand for efficient, convenient, and inexpensive catalysts. Herein, we present a spray-drying-assisted way to construct magnetic hollow micro-sized nanoaggregates (HMNAs) by assembling composite metal oxide nanoparticles to depolymerize PET synergistically. The as-prepared ZnO–Fe3O4 HMNAs completely depolymerized PET with a high monomer yield of 92.3% in a short period of 30 min at 190 °C, far above individual ZnO and Fe3O4 nanoparticles (NPs). The composite HMNAs can be magnetically separated in a few minutes and maintain a high activity for 5 cycles. DFT study reveals that the HMNAs effectively facilitated glycolysis by the high content of Lewis acid sites as well as the stronger adsorption between PET and the catalyst owing to the structural synergy effect of ZnO–Fe3O4 HMNAs. Furthermore, this spray drying strategy as a versatile and scalable methodology is extended to fabricate other HMNAs, exhibiting a similarly enhanced efficiency of glycolysis. The HMNAs are expected to open up avenues for the design of catalysts for upcycling of discarded plastics.
研究领域:
材料科学
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环境科学
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化学工程
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纳米技术
✓ 已验证
产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）