NEW JOURNAL OF CHEMISTRY
·
2023
·Vol. 47
·期 31
·14646-14655
·
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
·
材料科学
·
催化反应
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2024
·
IF 4.1
Jin-Tao Du,Hao Wu,Yao Jie,Yi Xia,Zhenyu Yang,Hong Yan,Qian Wang,Jie-Xin Wang,Jian-Feng Chen
Efficient and sustainable recycling of polyethylene terephthalate (PET) is essential in mitigating its environmental impacts on climate, human health, and global ecosystems. Glycolysis, a closed-loop recycling method that converts PET into bis(2-hydroxyethyl) terephthalate (BHET), stands out as one of the most promising methods due to its mild operating conditions and environmentally friendly nature. However, the complete convert PET into BHET with a high stability are still challenging. In this study, magnetically recyclable CoFe 2 O 4 nanocatalysts were synthesized by the solvothermal method and surface-modulated with Na 3 Cit·2H 2 O as a modifier. When utilizing an optimized CoFe 2 O 4 catalyst, conversion of PET achieved 100 %, with a BHET yield of 91.7 % at 210 °C for 1 h. The excellent catalytic performance of CoFe 2 O 4 is attributed to its smaller particle size, improved dispersion, higher surface Co/Fe ratio, and increased oxygen vacancies, all of which can be achieved through straightforward surface modulation. DFT calculations of M−O distance (M = Co or Fe), adsorption energy, and Bader charges confirm that a higher surface Co/Fe ratio enhanced PET glycolysis, consistent with experimental results. Additionally, a modified energy economy coefficient ( ε m ) was proposed to characterize the catalytic efficiency. The ε m value of CoFe 2 O 4 -60 % was 0.624, indicating promising applications in efficient PET glycolysis. This work presents a versatile approach for easily manipulating the surface properties of magnetic catalysts and identifies key factors for achieving high performance in PET-to-BHET conversion. It offers valuable guidelines for the future design of nanoparticle catalysts with magnetic properties for chemocatalytic reactions.
研究领域:
材料科学
·
环境科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
RSC Sustainability
·
2025
·
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
·
催化化学
·
化学回收
·
反应工程
·
环境化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF POLYMERS AND THE ENVIRONMENT
·
2024
·
IF 4.7
Yang Ge,Wu Hao,Huang Ke,Ma Yukun,Chen Qi,Chen Yun,Lin Shanshan,Guo Hailing,Li Zhibo
The recycling of polyethylene terephthalate (PET) waste plastics has garnered global attention as an essential area of research to address. Chemical upcycling methods, such as glycolysis, offers a visible solution by directly converting PET wastes into high-valued monomers, enabling their reintegration into the plastic life cycle. However, the recovery of metal salt catalyst and the thermal stability of organic catalyst pose challenges in PET glycolysis. Zeolites with strong Brønsted acid are widely used in the degradation of polyolefins, but in PET glycolysis, they face the problems of acid site mismatch and difficult contact with PET. In this work, nanosized FAU-type zeolite catalysts (100-FAU) were employed to carry out PET glycolysis, which were green synthesized at low temperature without organic template. In comparison to commercial FAU-type catalysts, 100-FAU exhibits enhanced Lewis acidity and basicity along with increased accessibility to active sites. The 100% degradation of PET was achieved within 1 h, resulting in a BHET yield of 64.2%. Prolonging the reaction time to 1.5 h led to an enhanced BHET yield of 72.1%. The quality of the primary product bis(2-hydroxyethyl) terephthalate (BHET) was verified through IR, DSC, and NMR characterizations. Furthermore, as a solid catalyst with high thermal stability, zeolite can be easily recovered via filtration and demonstrated stable performance over at least 5 cycles, and proved effective for glycolysis of commercially waste PET plastics. The acid–base dual-functional catalytic mechanism of Na-form FAU in PET glycolysis was proposed. Under its guidance, the promoting effect of other Na-form nanosized zeolites on PET degradation was verified.
研究领域:
材料科学
·
化学工程
·
环境科学
·
催化
✓ 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）