POLYMERS & POLYMER COMPOSITES
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2022
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IF 1.841
Ming Gong,Daijun Zhang,Jiayang Zhang,Jun Li,Xiangbao Chen
Vinyl polymerization is an important path for in-situ polymerization of thermoplastic resins. BPO (Benzoyl peroxide) and DMT (dimethyl-p-toluidine) were chosen to initiate the radical polymerization of MMA (methyl methacrylate) in this work. Optimization of initiator concentration was studied through reaction rate of polymerization progress and properties of PMMA (polymethyl methacrylate). At first, the catalytic of DMT in MMA polymerization was studied through polymerization experiments and rheological experiments. Results showed that DMT could catalyze more than one molecular BPO in the whole reaction period. It can catalyze the decomposition of BPO after being connected to PMMA chains. Second, the BPO: DMT ratio was set to 2:1 to study the ideal content by comparing the mechanical properties of PMMA. Results showed that with the increase of initiator contents, Tg, molecular weight, and residual monomer were all declining. Meanwhile, the mechanical properties of PMMA matrix first increased and then decreased. This phenomenon was analyzed by 1H-NMR and SEM. And the optimal BPO-DMT concentration was 1.0 mol%–0.5 mol%.
研究领域:
材料科学
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化学工程
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产品关联
DOI
高影响因子
GREEN CHEMISTRY
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2024
·Vol. 26
·期 11
·6748-6759
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IF 9.3
Yitian Zhang,Jie Gao,Chao Jiang,Gang Luo,Jiajun Fan,James H. Clark,Shicheng Zhang
Chemical upgrading as a recycling technology for poly(ethylene terephthalate) (PET) waste plastic is an effective way to help solve the current challenges of plastic pollution. Catalytic methanolysis technology enables the depolymerization of PET into high-value dimethyl terephthalate (DMT) monomers under relatively mild conditions, thereby achieving closed-loop recycling of PET waste plastic. In this study, we compared the catalytic efficiency of Cu/SiO2 catalysts prepared by three different methods for the depolymerization of PET to DMT. Cu/SiO2-IM, prepared through the impregnation method, exhibited the highest activity, with PET conversion and DMT selectivity reaching 92.35% and 99.0%, respectively, at 200 °C without any initial gas pressure. The exceptional performance of Cu/SiO2-IM can be attributed to its small metal particles, substantial specific surface area, a high ratio of Brønsted acid sites (BAS) to Lewis acid sites (LAS) and the balance of Cu+ and Cu0 active sites on the catalytic surface. Furthermore, possible reaction mechanisms of Cu-based catalysts in the catalytic methanolysis of PET were investigated: Cu+ initiates the attack on the carbon groups along the long PET chain and enhances the nucleophilic attack during the depolymerization reaction, while Cu0 readily interacts with the hydroxyl group of methanol, leading to the formation of a new ester group between the oxygen atom in the hydroxyl group of methanol and the carbon atom in the CO group of PET polyester. This low-cost and high-efficiency catalytic methanolysis study provides a practical approach to PET waste plastic recycling.
研究领域:
化学工程
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环境科学
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材料科学
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产品关联
DOI
高影响因子
GREEN CHEMISTRY
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2026
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IF 10.6
Lei Yang,Jiacheng Gao,Min Su,Li Yua,Yuan Wang,Dajun Wang,Heng Zheng,Shaojun Yuan,Like Ouyang
The depolymerization of waste polyethylene terephthalate (PET) has predominantly focused on zinc-based catalysts, benefiting from their stable Lewis acidity derived from unique 3d orbital electronic configurations. In contrast, manganese-based catalytic materials, which share similar electronic structural features, have rarely been explored. This study developed a synergistic catalytic system using commercially available, low-cost homogeneous MnCl₂·4H₂O and heterogeneous Mn₂O₃ for the methanolysis of PET which achieved complete PET conversion within 1 hour at 180°C with a dimethyl terephthalate (DMT) yield of 95.35%. Compared with other catalytic systems for PET depolymerization, the present system uniquely integrates the capability of homogeneous Mn²⁺ ions to rapidly activate methanol and swell PET with the structural stability and ease of recovery inherent to the heterogeneous Mn₂O₃ oxide. Through systematic in-situ and ex-situ characterizations (XRD, XPS, in-situ DRIFTS, etc.), it was revealed that the essence of the synergistic effect originates from a dynamic composite active center formed at the interface between Mn²⁺ and Mn₂O₃, which efficiently stabilizes key reaction intermediates and promotes product desorption. Aspen Plus process simulation and economic analysis further validate its industrial potential: although the synergistic system introduces an additional step for homogeneous catalyst recovery, its superior product yield and lower activation energy grant it significant economic advantages and industrial potential. In summary, this work establishes a novel homo-heterogeneous catalytic system, offering a strategic approach to develop efficient and scalable solutions for polyester degradation.
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DOI
高影响因子
CHINESE JOURNAL OF CHEMICAL ENGINEERING
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2017
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IF 1.174
Chunyuan Wu,Youwei Cheng,Lijun Wang,Xi Li
The binary solid–liquid equilibrium of Dimethyl Terephthalate (DMT), Dimethyl Isophthalate (DMI) and Dimethyl Phthalate (DMP) was investigated by experiment and differential scanning calorimetry (DSC). The result demonstrated DMT/DMI and DMT/DMP systems are eutectic while DMI/DMP is a solid-solution system. The eutectic temperature of DMT/DMI system is 336.7 K and that of DMT/DMP is 271.1 K. Furthermore, a classical solid–liquid phase equilibrium model was used to fit the experimental data of the eutectic systems of DMT/DMI and DMT/DMP and the theoretical model could describe the eutectic solid–liquid phase diagrams properly.
研究领域:
化学工程
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热力学
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分离过程
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材料科学
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DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
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2025
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IF 4.3
Chunrui Rong,Dongxia Yan,Jiabao Li,Jian Feng,Jiayu Xin,Qing Zhou,Yi Li,Junli Xu,Xingmei Lu
The increase in the usage of polyethylene terephthalate (PET) leads to the generation of a large amount of waste, which may cause carbon emissions and waste of petroleum resources. The methanolysis method has attracted global attention, but limited by high reaction temperature and excessive use of methanol. We report here an efficient catalyst, tetramethylguanidine/1,5-diazabicyclo[4.3.0]-5-non-ene (TMG/DBN), converting waste PET into regenerated dimethyl terephthalate (rDMT) under 100 °C with almost equivalent methanol, achieving 100 % PET conversion and 93.1 % yield of rDMT. A series of analytical methods and theoretical calculations were used to reveal the enhanced interaction between the catalyst and reactants, which facilitates the degradation of PET at low methanol dosages. In addition, a kinetic model was also developed with a relatively low activation energy of 84.9 kJ/mol. This work provides an effective strategy for the up-grading recycling of waste PET under mild reaction conditions.
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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产品关联
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
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2024
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IF 20.2
Jiang Li,Zhidong An,Yue Kong,Le Zhang,Jinqi Yang,Xiaojing Wang,Jiatian Wang,Delong Duan,Qi Zhang,Ran Long,Dionisios G. Vlachos,Zhenxing Li
The conversion of polyethylene terephthalate (PET) plastic into low-boiling monomers like para -xylene (PX) that can be purified easier with lower energy consumption represents a promising strategy for circular economy that seamlessly integrating into current prevailing high-quality PET production chain. Herein, a selective bimetallic RuFe catalyst was successfully fabricated for hydrodeoxygenation (HDO) of dimethyl terephthalate (DMT) (a model compound of PET) and PET plastics to PX with yield as high as 88.9 % and 82.6 %, respectively, comparable to state-of-the-art examples. H 2 -TPR and EXAFS combined with benchmark test over model catalysts confirmed that small Ru clusters and Ru-N x coordination are responsible for the high aromatics selectivity, on which vertical adsorption of carbonyl group (C O) is preferred. This study not only shows a promising PX-based PET recycling route, the highly selective C–O bond cleavage on Ru catalyst and corresponding structure-selectivity relationship also guide the catalyst design for other value-added biomass-based HDO reactions.
研究领域:
化学工程
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材料科学
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催化
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环境科学
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产品关联
DOI
高影响因子
危险品化学品经营许可证（带存储）