Reaction Chemistry & Engineering
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2025
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IF 3.1
Xueqian Zhang,Jiasong Yan,Shuai Yuan,Shanqing Yu,Qingyu Liu,Xikai Wang,Rui Li
Whether cycloalkanes undergo six- or five-membered ring-opening reaction pathways remains controversial. In this work, the catalytic cracking reactions of cyclohexene and 1-methylcyclopentene, as model compounds, were investigated in a pulse microreactor. The characteristics of the reactions of the two model compounds were compared in terms of isomerization, cracking, and hydrogen transfer reaction, and the reasons for the differences in their catalytic reactions were analyzed in combination with thermodynamic and molecular simulation calculations. The results have shown that the catalytic cracking product distributions of cyclohexene and 1-methylcyclopentene were similar owing to their easy mutual isomerization; the five-membered ring-opening cracking pathway was more thermodynamically advantageous than that of six-membered ring-opening cracking, and therefore, the yield of the ring-opening cracking product of 1-methylcyclopentene was comparatively higher; the main products of the hydrogen transfer reaction of the two compounds were alkanes and aromatic hydrocarbons. By comparing the product distributions and reaction activation energies, the ring-opening reaction pathways were clarified, and the catalytic cracking reaction networks of cyclohexene and 1-methylcyclopentene were established.
研究领域:
化学
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催化反应
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DOI
高影响因子
Journal of Coatings Technology and Research
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2024
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IF 2.3
Ling Chen,Zhou Rudong,Xiang Yanli,Fang Jianbo,Meng Xu,Ren Qiang,Wang Chenyi
Solvent-free epoxy-based intumescent fire-retardant coatings are of significant importance in harsh environments, such as petrochemical facilities, due to their excellent overall protection performance. However, the challenge of low-temperature brittleness and limited intumescence resulting from a highly crosslinked structure still persists. In this study, epoxy-terminated polyester oligomers with an asymmetric structure and low viscosity were synthesized using azelaic acid (AA) and dodecanedioic acid (DA) as dibasic acids with odd and even carbon numbers to address this challenge. The chemical structures of these polyester were thoroughly characterized. Among them, the polyester prepared with a molar ratio of 1:3 for AA and DA (ADE) was optimized as a suitable toughener for solvent-free intumescent fire-retardant coatings based on E-51 epoxy resin. The influence of ADE dosage on thermal stability, fire resistance performance, flexibility, and freeze cracking resistance was investigated in detail. The findings demonstrated that incorporating 50% ADE in ADE/E-51 blends resulted in coating film with an appropriate glass transition temperature and thermal deformation property to match the intumescence behavior of intumescent flame-retardant system. The coating formulated in this way exhibited the best fire protective performance, toughness and freeze cracking resistance.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
Catalysis Science & Technology
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2022
·Vol. 12
·期 19
·5879-5890
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IF 6.177
Dengfeng Dai,Chao Feng,Minmin Wang,Qingzhou Du,Dandan Liu,Yuan Pan,Yunqi Liu
Biomass-based chemicals as a renewable alternative to petroleum-based chemicals are of great significance. The conversion of biomass-based furfuryl alcohol to pentanediol, including 1,5-pentanediol and 1,2-pentanediol, is explored over a series of bifunctional Cu/MFI catalysts in a continuous-flow reactor. These catalysts are synthesized by supporting copper nanoparticles on MFI zeolites with varying molar ratios of SiO2/Al2O3. Among them, the Z60-10Cu catalyst containing balanced Cu0–Cu+ and Brønsted acid sites exhibits excellent performance, and a high furfuryl alcohol conversion of 99.5% and selectivity of 85.2% for 1,5-pentanediol (69.2%) and 1,2-pentanediol (16.0%) could be achieved (hydrogen pressure: 2.5 MPa) at 160 °C. The experimental results and the results obtained using the DFT technique revealed that the high catalytic activity realized during the processes of ring-opening and hydrogenation could be attributed to the synergistic effect between the Cu species and Brønsted acid sites. The Brønsted acid sites on the Si(OH)Al groups significantly affect the ring-opening process of furfuryl alcohol. The methoxy group on furfuryl alcohol adsorbs on the Cu+ sites, and the hydrogenation saturation of the ring-opening intermediate is realized under the influence of the activated hydrogen units on the Cu0 sites. The results reported herein could help promote the continuous production of high value-added pentanediol from biomass-based raw materials in the presence of non-noble metal catalysts. An economical and feasible path for the transformation of biomass resources into high value-added fine chemicals could also be developed.
研究领域:
生物化学
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催化化学
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材料科学
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DOI
高影响因子
ChemSusChem
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2024
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IF 7.5
Shenyu Wang,Junjie Zhang,Ying Zhang
Graphical The CoO@Co core-shell catalyst, 7Co-0.2Fe/CeO 2 , efficiently catalyzes the hydrogenation and ring-opening of furfural to 1,5-pentanediol, with a high productivity of 54.76 mmol/g Co /h, representing the top activity level among the reported catalysts. The addition of Fe optimizes the Co 2+ /Co 0 ratio, improves substrate adsorption, and prevents the formation of tetrahydrofurfuryl alcohol, a saturated furan byproduct. In the conversion of furfural using non-noble metal catalysts, preferential cleavage of the C2−O bond followed by hydrogenation of the C=C bond facilitates selective access to valuable 1,5-pentanediol (1,5-PeD). Herein, we developed CeO₂ loaded core-shell CoO@Co nanoparticle catalysts. Adjusting Co loading, Fe doping, and reduction temperature improved reaction efficiency. 7Co-0.2Fe/CeO₂ catalysts reduced at 500 °C demonstrated optimal performance. 1,5-PeD produced at 54.76 mmol/g Co /h, representing the top activity levels among the reported catalysts. H₂-TPR, XRD, HAADF-STEM, FT-IR, XPS, and XANES were employed to investigate the catalyst structure-activity relationship. Co 2+ cleaves furan ring C−O bond, Co⁰ promotes double-bond hydrogenation. The CoO@Co structure favors the desired 1,5-PeD production route. Trace Fe species optimize the Co 2+ /Co⁰ ratio, enhance the substrate adsorption, and inhibit the furan ring saturation. These findings emphasize the importance of fine-tuning catalyst structure and composition for selectivity improvement.
研究领域:
化学工程
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催化科学
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可再生资源转化
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DOI
PubMed
高影响因子
CATALYSIS LETTERS
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2022
·Vol. 153
·期 7
·2107-2114
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IF 2.936
Zhao Wenli,Niu Xiaopo,Liu Guangni,Zhang Xiurong,Wang Qingfa
Three kinds of Pt nanocrystals with different morphologies (5 nm cubes, 10 nm cubes and 5 nm truncated octahedrons) were synthesized and employed to fabricate Pt/CNT-USY catalysts for selective ring opening of decalin. The 5 nm truncated octahedral Pt/CNT-USY with exposed (100) and (111) facets exhibited higher yield of ring-opening products (53.9 wt%) than the CNT-USY-supported 5 nm cubic Pt catalyst enclosed by the (100) facets (39.6 wt%). Moreover, the 5 nm cubic Pt showed better catalytic activities compared to the 10 nm cubic Pt/CNT-UST catalyst, which ascribed to the smaller size of Pt NCs enriched more revealable metal active sites. DFT calculations demonstrated that the adsorption of decalin on Pt (111) was stronger than that on Pt (100) facets, which was profitable for the selective ring-opening reaction. Graphical Abstract
研究领域:
催化化学
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材料科学
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理论计算化学
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DOI
高影响因子
WATER RESEARCH
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2017
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IF 6.942
Xing Ding,Shengyao Wang,Wanqiu Shen,Yi Mu,Li Wang,Hao Chen,Lizhi Zhang
In this study, an electrochemical/electro-Fenton oxidation (EC/EF) system was designed to degrade atrazine, by utilizing boron-doped diamond (BDD) and Fe@Fe 2 O 3 core-shell nanowires loaded active carbon fiber (Fe@Fe 2 O 3 /ACF) as the anode and the cathode, respectively. This EC/EF system exhibited much higher degradation rate, decholorination and mineralization efficiency of atrazine than the electrochemical (EC) and electrochemical/traditional electro-Fenton (EC/TEF) oxidation counterpart systems without Fe@Fe 2 O 3 core-shell nanowires. Active species trapping experiment revealed that Fe@Fe 2 O 3 could activate molecular oxygen to produce more OH through Fenton reaction, which favored the atrazine degradation. High performance liquid chromatography , high performance liquid chromatography-mass spectrometry and gas chromatography-mass spectrometry were applied to probe the decomposition and mineralization of atrazine during this novel EC/EF process, which revealed that two intermediates of triazinons (the isomerization of hydroxylated atrazine) were generated during the electrochemical/electro-Fenton oxidation of atrazine in the presence of Fe@Fe 2 O 3 core-shell nanowires. The experimental and theoretical calculation results suggested that atrazine might be degraded via a triazinon ring opening mechanism, while the presence of Fe@Fe 2 O 3 notably accelerated the decholorination process, and produced more hydroxylated products to promote the generation of trazinons and the subsequent ring cleavage as well as the final complete mineralization. This work provides a deep insight into the triazine ring opening mechanism and the design of efficient electrochemical advanced oxidation technologies (EAOTs) for persistent organic pollutant removal .
研究领域:
环境科学
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化学工程
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产品关联
DOI
PubMed
高影响因子
Polymers
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2022
·Vol. 14
·期 4
·738
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IF 4.967
Wenhao Zhang,Jianchao Zhou,Zhijin Cao,Xinxing Wu,Hui Wang,Shuaibo Han,Yan Zhang,Fangli Sun,Ting Zhang
The extension of wood to a wider field has been restrained significantly due to its dimensional instability that arises from variation in moisture content, which in turn brings about the risk of cracking, warping or distortion. This work proposed a novel strategy to stabilize wood by means of the in situ construction of a thermotropic shape memory polymer (SMP) inside wood. The cross-linked copolymer network (PMP) with good shape memory behavior was first investigated based on the reaction of methyl methacrylate (MMA) and polyethylene glycol diacrylate (PEGDA) in a water/ethanol solution; then, the PMP was constructed inside wood via vacuum-pressure impregnation and in situ polymerization. The weight gain, volume increment and morphology observations clearly revealed that the PMP was mainly present in wood cell lumens, cell walls and pits. The presence of PMP significantly enhanced the dimensional stability of and reduced the cracks in wood. The desirable shape recovery abilities of PMP under heating-cooling cycles were considered to be the main reasons for wood dimensional stabilization, because it could counteract the internal stress or retard the shrinkage of cell walls once water was evaporated from the wood. This study provided a novel and reliable approach for wood modification.Keywords:shape memory polymer;wood;in situ construction;dimension stability;anti-cracking
研究领域:
材料科学
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林业工程
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产品关联
DOI
PubMed
高影响因子
PROGRESS IN ORGANIC COATINGS
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2022
·
IF 6.206
Weiwei Li,Chunyang Wei,Jiyun Tang,Zongkui Li,Xiaowei An,Qi Li,Jingjing Wang,Liwei Liu
Long-term protection in highly corrosive environments has advanced to use high-solid coatings with high thickness, known as high-build coatings. However, these coatings were found to be more susceptible to cracking and delamination failures in-service with temperature variations. To understand how a high-build film is stressed at different temperatures, we developed an efficient measurement method by employing imaging scanning device and image analysis to quantitatively evaluate internal stress in two purposely formulated epoxy coatings with different elasticities through 30 thermal cycles between −25 to 50 °C. The results showed that the magnitude of internal stress was dependent on the coating elasticity, film thickness, and the difference in coefficient of linear thermal expansion (CTE) between the coating and its substrate apart from the service temperature and the thermal cycles. Moreover, thicker coating develops a significantly higher internal stress, which explains why cracking or delamination is typically associated with excessively thick coatings. The investigated mechanisms of the stress development during thermal cycling will be a useful guide to formulate mechanically durable high-build coatings.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
ENVIRONMENTAL SCIENCE & TECHNOLOGY
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2023
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IF 11.4
Xifen Zhu,Yuanyuan Yu,Weikun Meng,Jiahui Huang,Guanyong Su,Yin Zhong,Xiaolong Yu,Jianteng Sun,Ling Jin,Ping’an Peng,Lizhong Zhu
Fluorinated liquid crystal monomers (FLCMs) have been suggested as emerging contaminants, raising global concern due to their frequent occurrence, potential toxic effects, and endurance capacity in the environment. However, the environmental fate of the FLCMs remains unknown. To fill this knowledge gap, we investigated the aerobic microbial transformation mechanisms of an important FLCM, 4-[difluoro(3,4,5-trifluorophenoxy)methyl]-3, 5-difluoro-4′-propylbiphenyl (DTMDPB), using an enrichment culture termed as BG1. Our findings revealed that 67.5 ± 2.1% of the initially added DTMDPB was transformed in 10 days under optimal conditions. A total of 14 microbial transformation products obtained due to a series of reactions (e.g., reductive defluorination, ether bond cleavage, demethylation, oxidative hydroxylation and aromatic ring opening, sulfonation, glucuronidation, O-methylation, and thiolation) were identified. Consortium BG1 harbored essential genes that could transform DTMDPB, such as dehalogenation-related genes [e.g., glutathione S-transferase gene (GST), 2-haloacid dehalogenase gene (2-HAD), nrdB, nuoC, and nuoD]; hydroxylating-related genes hcaC, ubiH, and COQ7; aromatic ring opening-related genes ligB and catE; and methyltransferase genes ubiE and ubiG. Two DTMDPB-degrading strains were isolated, which are affiliated with the genus Sphingopyxis and Agromyces. This study provides a novel insight into the microbial transformation of FLCMs. The findings of this study have important implications for the development of bioremediation strategies aimed at addressing sites contaminated with FLCMs.
研究领域:
环境科学
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微生物学
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产品关联
DOI
PubMed
高影响因子
Environmental Technology & Innovation
·
2021
·
IF 5.263
Yuying Zhu,Baoqiang Chang,Xue Sun,Haijian Luo,Wenhui Wang,Chaolin Li
The presence of venlafaxine, one of the popular antidepressants, in environmental aquatic media has become a rising issue and potential threat to global ecology and human health. However, advanced technologies for efficient venlafaxine degradation remain underdeveloped. Herein, we propose to use chloride-mediated electrochemical degradation to efficiently remove venlafaxine in aqueous media. The degradation rate of venlafaxine can be significantly increased when Cl − is added to the conventional electrochemical degradation process. It is found the Cl − can convert to Cl ⋅ , which selectively attacks benzene ring and accelerates its opening, thus leading to the improved degradation and mineralization performance of venlafaxine. Based on the analysis of reactive species and degradation intermediates, the degradation pathways with and without Cl − were proposed. Toxicity test demonstrates that the toxic oxidation products formed during venlafaxine degradation could be completely mineralized in the chloride-mediated electrochemical degradation process. This work demonstrates the chloride-mediated advanced oxidation technology may be a promising way to degrade venlafaxine, which may also apply to other emerging antidepressants contained benzene ring, thus paving a new route for the removal of organic pollutants.
研究领域:
环境科学
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药理学
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化学工程
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DOI
高影响因子
Journal of the American Chemical Society
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2014
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IF 11.444
Xibin Pang,Wei Chang,Chuncheng Chen,Hongwei Ji,Wanhong Ma,Jincai Zhao
The molecules O2 and H2O dominate the cleavage of aromatic sp2 C–C bonds, a crucial step in the degradation of aromatic pollutants in aqueous TiO2 photocatalysis, but their precise roles in this process have remained elusive. This can be attributed to the complex oxidative species involved and to a lack of available models for reactions with a high yield of direct products. Here, we used oxygen-18 isotope labeled O2 and H2O to observe the aromatic ring-opening reaction of the model compound 3,5-di-tert-butylcatechol (DTBC), which was mediated by TiO2 photocatalysis in an aqueous acetonitrile solution. By analyzing the primary intermediate products (∼75% yield), especially the seven-membered ring anhydrides that were formed, we obtained direct evidence for the oxygen atom of dioxygen insertion into a C–C bond of the aromatic ring. This indicates that molecular oxygen is the ultimate ring-opening agent in TiO2 photocatalysis and that it undergoes single O atom incorporation rather than the previously proposed molecular oxygen 1,2-addition processes. The ratio of intradiol to extradiol products depends on the particle size of TiO2 catalysts used, which suggests that the O2 activation is correlated with the available coordination sites on the TiO2 surface in the photocatalytic cleavage of the aromatic ring.
研究领域:
环境科学
·
化学
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DOI
高影响因子
PROGRESS IN ORGANIC COATINGS
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2022
·
IF 6.206
Yun Feng,Wei Qu,Yuzhang Wu,Jingpeng Zhang,Limin Peng
Melamine–formaldehyde (MF) resin-impregnated paper-decorated panels are prone to surface cracking, which can be reduced by changing the brittle structure of the MF resin. To increase the curing degree and toughness of the resin, a hexamethylene diisocyanate trimer blocked with methyl ethyl ketoxime (ME-HDI-tri) was used as a temperature-responsive crosslinker. This latent crosslinking agent only worked above 120 °C, which prevented it from participating in cross-linking reactions during the preparation of the impregnated paper. The chemical structures of the modified MF resins (ME-HDI-tri-MF) were characterized by Fourier-transform infrared (FTIR) spectroscopy. The curing behaviors of the MF resins were characterized by thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical thermal analysis (DMTA). Impregnated paper was prepared with ME-HDI-tri-MF, and its tensile strength and elongation at break were tested. Blockboard was prepared with ME-HDI-tri-MF, and its cracking and corrosion resistance were tested. The absorption peak of the methylene chain was observed in the FTIR spectrum of ME-HDI-tri-MF after curing, which indicated that ME-HDI-tri participated in the curing reaction of the MF resin. With the addition of ME-HDI-tri 5 %, the curing temperature of the MF resin decreased from 142 °C to 130 °C, and the ultimate tensile stress and elongation at break of the modified impregnated paper increased by 97.70 % and 86.25 %, respectively. The cracking and corrosion resistance of the decorated panel prepared with ME-HDI-tri-MF were also improved. After adding 3 % ME-HDI-tri, the surface cracking of the decorated panels was prevented, which extended the service life and broadened the application range of the decorated panels.
研究领域:
材料科学
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化学工程
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DOI
高影响因子
危险品化学品经营许可证（带存储）