EUROPEAN POLYMER JOURNAL
·
2023
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IF 6
Xiongfei Zhang,Chuang Ma,Peiyu Liu,Dan Huang,Pengyun Li
Because of its high crosslinking density, compact structure and stable performance, epoxy resin is difficult to be degraded, which leads to serious environmental pollution problems. In this work, using dipropylene glycol dimethyl ether as swelling agent and nitric acid as oxidant, the degradation of amine cured epoxy resin was studied. Results are as follows: The degradation rate obtained by swelling agent assisted oxidation degradation method is much higher than that obtained by oxidation degradation method only. And the degradation rate of the epoxy resin even reached 100 % at 100 °C only in an hour under the condition of swelling agent assisted nitric acid. FT-IR and GC–MS showed that the degradation was mainly caused by that the C N bond in the molecular chain was gradually weakened and fractured finally. The molecular weight of the degradation product was relatively dispersive, which was composed of low molecular polymer and small fragments, and the molecular weight of low molecular polymer was about 2167. And the degradation products primarily contain 4-isopropylphenol and (allyloxy)benzene rings. This work provides a new way to solve the problem about the degradation, recycling and pollution of epoxy resin.
研究领域:
材料科学
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环境科学
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产品关联
DOI
高影响因子
Frontiers of Chemical Science and Engineering
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2023
·Vol. 17
·期 12
·1986-2000
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IF 4.5
Xue Yi-Fan,Feng Jie,Song Yun-Cai,Li Wen-Ying
Breakage of the C–N bond is a structure sensitive process, and the catalyst size significantly affects its activity. On the active metal nanoparticle scale, the role of catalyst size in C–N bond cleavage has not been clearly elucidated. So, Ru catalysts with variable nanoparticle sizes were obtained by modulating the reduction temperature, and the catalytic activity was evaluated using 1,2,3,4-tetrahydroquinoline and o -propylaniline with different C–N bond hybridization patterns as reactants. Results showed a 13 times higher reaction rate for sp 3 -hybridized C–N bond cleavage than sp 2 -hybridized C–N bond cleavage, while the reaction rate tended to increase first and then decrease as the catalyst nanoparticle size increased. Different concentrations of terrace, step, and corner sites were found in different sizes of Ru nanoparticles. The relationship between catalytic site variation and C–N bond cleavage activity was further investigated by calculating the turnover frequency values for each site. This analysis indicates that the variation of different sites on the catalyst is the intrinsic factor of the size dependence of C–N bond cleavage activity, and the step atoms are the active sites for the C–N bond cleavage. When Ru nanoparticles are smaller than 1.9 nm, they have a strong adsorption effect on the reactants, which will affect the catalytic performance of the Ru catalyst. Furthermore, these findings were also confirmed on other metallic Pd/Pt catalysts. The role of step sites in C–N bond cleavage was proposed using the density function theory calculations. The reactants have stronger adsorption energies on the step atoms, and step atoms have d-band center nearer to the Fermi level. In this case, the interaction with the reactant is stronger, which is beneficial for activating the C–N bond of the reactant.
研究领域:
催化化学
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材料科学
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理论化学
✓ 已验证
DOI
高影响因子
BIOCHEMICAL ENGINEERING JOURNAL
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2024
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IF 3.7
Zhimei Zhang,Chao Zhao,Tianming Wu,Yanfeng Xu,Lu Wang,Yusheng Niu
The accumulation of glyphosate during its application in agriculture and its toxicity seriously threaten ecosystems and human health. Currently, glyphosate residual contamination is mainly accomplished through bioremediation techniques based on enhanced microbial degradation activity. However, there are drawbacks, such as poor environmental adaptability of strains and low degradation efficiency. Therefore, in this study, an efficient glyphosate-degrading strain, Pseudomonas alcaligenes Z1–1, was isolated from herbicide-contaminated environments and was capable of completely degrading glyphosate at a concentration of 200 mg/L within 7 days. Kinetics analysis showed that glyphosate degradation was concentration-dependent, with a maximum tolerant concentration of 800 mg/L. Mass spectrometric analysis indicated that AminoMethylPhosphonic acid (AMPA) was the predominant intermediate produced in the degradation pathway of glyphosate, revealing that glyphosate destruction began with breaking the C-N bond. Whole genome sequencing identified the key genes potentially involved in glyphosate degradation, including the thiO , glpA , aroA , soxB , and argA genes. Furthermore, in contrast to the majority of the metabolic pathways previously reported for glyphosate degradation via glyphosate oxidoreductase , the breaking of the C-N bond was primarily catalyzed by glycine oxidase . Overall, this research provides novel insights into the mechanisms of glyphosate degradation, offering valuable degradation enzyme resources for future applications.
研究领域:
环境科学
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微生物学
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分子生物学
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产品关联
DOI
高影响因子
ACS Applied Nano Materials
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2020
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IF 0
Wei Zhao,Shuang Liu,Huishu Wang,Jun Yang,Xinhan Chen
Heterogeneous Pd has been developed as a well-known catalyst for debenzylation reactions via hydrogenative C–N bond cleavage. However, the extensive applications are still limited owing to a high loading and usage amount of the noble metal. Herein, well-dispersed Pd nanocatalysts over TiO2 were explored with a deposition–precipitation method and characterized by FESEM, physical adsorption, XRD, TEM, and XPS. It was proposed that the ultrasmall and electron-rich Pd nanoparticles can be enhanced over TiO2 rather than C, Al2O3, or SiO2. As representatives, the debenzylations of hexabenzylhexaazaisowurtzitane (HBIW) and tetraacetyldibenzylhexaazaisowurtzitane (TADBIW), which are key steps for the synthesis of CL-20 with the highest energy and density, were selected to evaluate the catalytic performances. It was found that Pd/TiO2 exhibited considerably low usage with high yields in the debenzylation processes of not only HBIW (1 wt ‰) but also TADBIW (4 wt ‰). Meanwhile, the superior catalytic activities can be maintained in the different reaction scales and can be repeated for TADBIW hydrodebenzylation. Hence, Pd nanoparticles supported on TiO2 can be considered to be suitable catalysts for highly efficient catalytic synthesis for hydrogenative C–N bond cleavage.
研究领域:
化学
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材料科学
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催化反应
✓ 已验证
产品关联
DOI
JOURNAL OF ORGANIC CHEMISTRY
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2021
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IF 4.354
Long Liu,Yuanyuan Tang,Kunyu Wang,Tianzeng Huang,Tieqiao Chen
A facile and general method for constructing carbon–heteroatom (C–P, C–O, C–S, and C–N) bonds via C–N cleavage of benzyl ammonium salts under transition-metal-free conditions was reported. The combination of t-BuOK and 18-crown-6 enabled a wide range of substituted benzyl ammonium salts to couple readily with different kinds of heteroatom nucleophiles, i.e. hydrogen phosphoryl compounds, alcohols, thiols, and amines. Good functional group tolerance was demonstrated. The scale-up reaction and one-pot synthesis were also successfully performed.
研究领域:
有机化学
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合成化学
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产品关联
DOI
PubMed
高影响因子
CATALYSIS LETTERS
·
2018
·Vol. 148
·期 9
·2636-2642
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IF 2.911
Yu Zongjiang,Zhai Guoqing,Xian Mo,Lu Ming,Wang Pengcheng,Jiang Tao,Xu Chao,Sun Weizhi
The cleavage of C–N single bonds of N -containing compounds provides either an excellent nitrogen source or an excellent carbon source. In this study, an efficient metalloporphyrins/H 2 O 2 cleavage of C–N bonds of arylpyrazoles was investigated. The effects of different factors, including different catalysts, catalyst dosages, H 2 O 2 dosages, reaction temperature and reaction time were studied. The experimental results showed that the optimal catalyst was FeTPPCl, and the yield of pyrazole derivatives could reach up to 12.3%, which was fourfold higher than hemin catalyzed reaction and closed to ceric ammonium nitrate catalyzed reaction, respectively. Compared with transition-metal-catalyzed and strong-oxidization cleavage of C–N bonds, this protocol is characterized by environmentally-friendly, stable, mild reaction conditions and simplified operation procedures. Graphical Abstract
研究领域:
有机化学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Environmental Sciences
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2022
·
IF 6.796
Yunlong Chen,Yingping Huang,Hailin Tian,Liqun Ye,Ruiping Li,Chuncheng Chen,Zhongxu Dai,Di Huang
With increasing concerns on the environment and human health, the degradation of glyphosate through the formation of less toxic intermediates is of great importance. Among the developed methods for the degradation of glyphosate, photodegradation is a clean and efficient strategy. In this work, we report a new photocatalyst by doping F ion on BiVO 4 that can efficiently degrade glyphosate and reduce the toxic emissions of aminomethylphosphonic acid (AMPA) through the selective (P)−C−N cleavage in comparison of BiVO 4 catalyst. The results demonstrate that the best suppression of AMPA formation was achieved by the catalyst of 0.3F@BiVO 4 at pH = 9 (AMPA formation below 10%). In situ attenuated total reflectance Fourier transforms infrared (ATR-FTIR) spectroscopy indicates that the adsorption sites of glyphosate on BiVO 4 and 0.3F@BiVO 4 are altered due to the difference in electrostatic interactions. Such an absorption alteration leads to the preferential cleavage of the C−N bond on the N−C−P skeleton, thereby inhibiting the formation of toxic AMPA. These results improve our understanding of the photodegradation process of glyphosate catalyzed by BiVO 4 -based catalysts and pave a safe way for abiotic degradation of glyphosate.
研究领域:
环境科学
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材料科学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
CHEMICAL ENGINEERING SCIENCE
·
2023
·
IF 4.7
Yi-Fan Xue,Jie Feng,Jin-Yao Ma,Wen-Ying Li
C–N bond breaking is a difficult but crucial step in the quinoline removal of coal-based liquids. Noble metal catalysts have higher C–N bond breaking activity, but their surface bond breaking mechanism is unclear. Atomic layer deposition creates more metal-oxide sites and generates different active species, which facilitates the mechanism study. For this reason, we used atomic layer deposition to deposit TiO 2 on the catalyst surface and suggested a more complete C–N bond breaking mechanism in this study. The particle size and pore structure of the catalyst did not change significantly after the deposition, and the hydrogen adsorption was reduced when there were too many layers deposited and the surface Pt sites were occupied to a high degree. TiO 2 is extremely susceptible to reduction to Ti 3+ under hydrogen, and can change the nature of the electron density of Pt through oxygen vacancies, creating Ti 3+ -Pt δ− sites that are prone to protonation reactions. That means, the occurrence of these protonation reactions not only easily breaks the C–N bond, but also accelerates the rate of C–N bond cleavage due to the increased H coverage on the surface of the xcTi-PtAl catalysts. And the Ti 3+ -Pt δ− sites in catalyst had a stronger adsorption effect on the nitrogen-containing compounds, which in turn lowered the energy barriers of bond cleavage. It is concluded that protonation is a necessary step before the C–N bond can be broken. The subsequent steps were showed by the DFT calculations that the nitrogen-containing compounds adsorbed on the Ti 3+ -Pt δ− sites undergo β-H fracture after the protonation reaction, with the elimination reaction cleaving the C–N bond. The xcTi-PtAl catalysts by atomic layer deposition of Ti not only improve the C–N bond breaking performance, but also improve bond breaking stability by a factor of four compared to the Pt/Al 2 O 3 catalysts.
研究领域:
催化化学
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能源化学
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表面科学
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产品关联
DOI
高影响因子
COMPOSITES SCIENCE AND TECHNOLOGY
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2024
·
IF 8.3
Chizhou Wang,Ning Zhang,Shaodi Wu,Weijie Wang,Peng Zhao,Shiyu Jia,Yongqin Qi,Xianglin Hou,Xiaojing Cui,Tiansheng Deng
Amine-cured epoxy resin (EP) is often compounded with carbon fiber (CF) used for wind power blades due to its excellent performance. However, the insolubility and infusibility of service-life-expired carbon fiber reinforced epoxy resin (CFREP) hinder its sustainable recycling. We reported a new strategy for efficient degradation of EP and CFREP with 0.5 mol% amphiphilic dodecylbenzenesulfonic acid (DBSA) in aqueous system. It was found that the strong lipophilicity of DBSA accelerated its enrichment on EP surface, and further promoted the diffusion of DBSA and H 2 O to the resin bulk phase. As a result, the degradation ratio of the EP powder reached 100 % at 190 °C only in 10 h. The characterization of FT-IR and NMR proved that the degradation mechanism of EP was the selective cleavage of C-N bond catalyzed by H + . The resin degradation products (RDP) containing active hydrogen were used to prepare polyurethane (PU) with good mechanical properties . This method achieves complete recycling of waste CFREP in aqueous systems.
研究领域:
材料科学
·
化学工程
✓ 已验证
产品关联
DOI
高影响因子
ACS Nano
·
2025
·
IF 16
Yong Li,Xiang Yu,Yu Fan,Guangxun Zhang,Songtao Zhang,Zhenyang Meng,Ziming Qiu,Yi-chun Su,Yangyang Sun,Nian-Tzu Suen,Hsiao-Chien Chen,Rongmei Zhu,Yecan Pi,Huan Pang
Two-dimensional (2D) conjugated metal–organic frameworks (c-MOFs) have attracted extensive interest in electrochemical fields due to their inherent electrical conductivity. However, the severe interlayer stacking still poses barriers toward their potential applications. The reliable synthesis of ultrathin c-MOF nanosheets is crucial yet remains challenging. Herein, we demonstrate an electrochemical exfoliation approach to obtain ultrathin nanosheets from layer-stacked c-MOF crystals. Our results reveal the electric field-induced ion intercalation mechanism and provide a viable method for the synthesis of ultrathin M-HHTP (M = Ni, Cu, Co; HHTP = 2,3,6,7,10,11-hexahydroxytriphenylene) nanosheets. To prove utility, the obtained Ni-HHTP nanosheets as urea oxidation reaction (UOR) catalysts achieve an ultrahigh current density of 165.7 mA cm–2 at 1.35 V versus a reversible hydrogen electrode and nearly 100% selectivity of N-products. Experimental characterization and theoretical calculations reveal that the fully exposed square planar NiO4 active centers effectively reduce the energy barrier of C–N bond cleavage for UOR and suppress the parasitic oxygen evolution reaction.
研究领域:
材料科学
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电化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
危险品化学品经营许可证（带存储）