JOURNAL OF CHEMICAL THERMODYNAMICS
·
2019
·
IF 2.29
Junjie Chen,Bo Jin,Guan Luo,Huihui Liu,Qingchun Zhang,Qi Huang,Rufang Peng
The thermodynamics and kinetics of the curing reactions between polyglycidyl nitrate (PGN) and toluene diisocyanate, isophorone diisocyanate, and polyaryl polymethylene isocyanate (PAPI) were studied by microcalorimetry. The reaction rate between PGN and PAPI was the fastest among the three reactions above. Three thermodynamics ( i.e. , activation enthalpy, entropy, and free energy), rate constant, and three thermokinetic parameters ( i.e. , activation energy, pre-exponential constant, and reaction order) of the curing reactions were obtained by calculating the results of the reaction between PGN and PAPI at a series of temperature from 303.15 K to 318.15 K. The linear relationship between ln k and the mole ratio of the isocyanate and hydroxyl groups was observed. The corresponding kinetic equation describing the curing reaction between PGN and PAPI was d α /d t = 10 −3.83 (1 − α ) 3.04 at 318.15 K.
研究领域:
高分子化学
·
热力学
·
反应动力学
·
功能材料
·
含能材料
✓ 已验证
DOI
高影响因子
CHINESE CHEMICAL LETTERS
·
2011
·Vol. 23
·期 1
·29-32
·
IF 0.775
Wen Hui Zhong,Ying Na Cui,Shen Min Li,Ying Ping Jia,Jing Mei Yin
The carbonylation of phenyl bromide catalyzed by Co(OAc) 2 has been investigated with PhCOPh as a sensitizer under visible light in the presence of basic additive. With strong base CH 3 ONa, PhCOOCH 3 is produced in 70% yield with 100% selectivity , the similar results are also obtained with a stronger base (CH 3 ) 3 CONa. However, with another strong base NaOH, the yield of the ester is only 40%. On the other hand, with weak base NaOAc or ( n -C 4 H 9 ) 3 N, phenyl bromide cannot be carbonylated. The results of carbonylation of the six substituted phenyl bromides suggest that the activities of o , m , p -BrC 6 H 4 CH 3 are similar to phenyl bromide, while the activities of o , m , p -BrC 6 H 4 Cl are higher with the high yields (≥93%) of the corresponding chloro-esters. In addition, the relative position of bromine and chlorine or methyl on phenyl ring has little effect on the activity of the carbonylation .
研究领域:
有机化学
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光催化
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均相催化
·
反应机理
·
绿色化学
✓ 已验证
DOI
高影响因子
CORROSION SCIENCE
·
2022
·
IF 7.72
Tianquan Liang,Zhihua Huang,Menghao Li,Wantong Xiao,Huan He,Aoping He,Xiyong Chen,Nengneng Luo
The thermochemical reaction behaviors between Y 2 O 3 and calcium-magnesium-aluminosilicate (CMAS) at 1250 °C∼1400 °C were investigated. A continuous-dense reaction layer mainly composed of Y-apatite phase quickly forms within 15 min, and its slow increasing thickness depends on the molten CMAS infiltration along the Y-apatite grain boundaries, the dissolution of the Y-apatite phase into the melt, the inhibiting effect on the CMAS penetration, and the reaction time and temperature. The CMAS crystallization occurs due to the change of chemical composition and the formation of other reaction products. The dense reaction layer shows good resistance to the molten CMAS infiltration.
研究领域:
材料科学
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无机非金属材料
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高温材料
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陶瓷涂层
·
腐蚀与防护
✓ 已验证
DOI
高影响因子
WATER RESEARCH
·
2024
·
IF 11.4
Yangmin Ren,Mingcan Cui,Yongyue Zhou,Shiyu Sun,Fengshi Guo,Junjun Ma,Zhengchang Han,Jooyoung Park,Younggyu Son,Jeehyeong Khim
Permeable reactive barrier (PRB) is an important groundwater treatment technology. However, selecting the optimal reactive material and estimating the width remain critical and challenging problems in PRB design. Machine learning (ML) has advantages in predicting evolution and tracing contaminants in temporal and spatial distribution. In this study, ML was developed to design PRB, and its feasibility was validated through experiments and a case study. ML algorithm showed a good prediction about the Freundlich equilibrium parameter (R 2 0.94 for K F , R 2 0.96 for n). After SHapley Additive exPlanation (SHAP) analysis, redefining the range of the significant impact factors (initial concentration and pH) can further improve the prediction accuracy (R 2 0.99 for K F , R 2 0.99 for n). To mitigate model bias and ensure comprehensiveness, evaluation index with expert opinions was used to determine the optimal material from candidate materials. Meanwhile, the ML algorithm was also applied to predict the width of the mass transport zone in the adsorption column. This procedure showed excellent accuracy with R 2 and root‐mean‐square‐error (RMSE) of 0.98 and 1.2, respectively. Compared with the traditional width design methodology, ML can enhance design efficiency and save experiment time. The novel approach is based on traditional design principles, and the limitations and challenges are highlighted. After further expanding the data set and optimizing the algorithm, the accuracy of ML can make up for the existing limitations and obtain wider applications.
研究领域:
环境工程
·
水文地质学
·
污染控制
·
环境修复技术
·
应用机器学习
✓ 已验证
DOI
高影响因子
Applications in Energy and Combustion Science
·
2022
·
IF 0
Bingzhi Liu,Long Zhu,Qingbo Zhu,Hao Lou,Qiang Xu,Zhandong Wang
Ozone-assisted combustion is an advanced combustion technology that is considered a promising means for the active control of combustion. Ozone addition can enhance combustion processes and extend the experimental parameters to extreme conditions. In this work, ozone-assisted low temperature oxidation of methanol and ethanol in a jet-stirred reactor (JSR) was carried out at atmospheric pressure, with a fuel initial mole fraction of 0.005, an equivalence ratio of 0.28, and in the temperature range of 330–800 K. Significant conversions of methanol and ethanol were observed in the low temperature region when ozone was added. Numerous intermediate species were analyzed and quantified by synchrotron vacuum ultraviolet photoionization mass spectrometry and gas chromatography, which are crucially important for unraveling the low temperature oxidation reaction network. The kinetic model of NUIGMech1.1 is tentatively updated to better explain the measured results, although the improvements of the C 1 –C 2 core mechanisms are difficult. Ozone addition enhances the action of the reaction channel of related radicals. Model analysis shows that the kinetics of Ö/ȮH/HȮ 2 atoms/radicals are crucial for the overall reaction progress, as well as the reaction of HȮ 2 radicals with ozone, which mainly contributes to the formation of ȮH radicals during the initial reaction stage. Inconsistency between measurements and model predictions highlights the considerable uncertainty in the C 1 -C 2 alcohols subchemistry at lower temperatures. The experimental results obtained in this work and model development will motivate further study of the low temperature oxidation chemistry of methanol and ethanol.
研究领域:
化学工程
·
燃烧化学
·
反应动力学
·
能源化学
·
大气压反应器
✓ 已验证
DOI
CATALYSIS TODAY
·
2018
·
IF 4.667
Xiaoyan Liu,Guojun Lan,Panpan Su,Lihua Qian,Tomas Ramirez Reina,Liang Wang,Ying Li,Jian Liu
The hydrogenation of levulinic acid to γ-valerolactone with water as solvent is a crucial reaction for producing fine chemicals. However, the development of highly stable catalysts is still a major challenge. Here, we prepared a Ru nanoparticles incorporated in mesoporous-carbon (Ru-MC) catalyst to achieve high stability in acidic aqueous medium. The Ru-MC showed excellent catalytic performance (12024 h −1 turnover frequency) in the hydrogenation of LA-to-GVL. Compared with Ru supported on mesoporous carbon catalyst (Ru/MC) prepared by conventional wet impregnation method, the Ru-MC showed excellent reusability (more than 6 times) and thermal stability (up to 600 °C). Based on H 2 -TPR-MS characterization, it was proposed that the incorporated structure significantly increased the interaction between Ru nanoparticles and carbon support, which effectively prevent the leaching and sintering of Ru nanoparticles and contributed to increased high reusability and thermal stability of the Ru-MC.
研究领域:
催化化学
·
绿色化学
·
生物质转化
·
纳米材料
·
能源化学
·
有机合成
✓ 已验证
DOI
高影响因子
MATERIALS & DESIGN
·
2016
·
IF 3.997
XinRong Liu,Ming Zhang,TingTing Yang,LiNa Wang,Han Zhu,ShunLi Wang,MingLiang Du
Carbon nanofibers served as nanoreactors for the design and construction of PtCo alloy carbon core-shell nanostructures with nitrogen doping (PtCo/NCNF) through a combination of electrospinning and nitrogen doping treatments. The PtCo/NCNF hybrid consists of PtCo alloy nanoparticles surrounded by a few of N-doped carbon layers , demonstrating a typical core-shell structures. The PtCo/NCNF hybrid can both served as electrode materials for electrocatalytic water splitting including hydrogen evolution reaction (HER) and oxygen evolution reaction (OER). For the HER performance, the PtCo/NCNF exhibits very small onset potential of 20 mV, an overpotential of 50 mV at a j (vs RHE) = 10 mA cm − 2 and Tafel slope of 30 mV dec − 1 . The PtCo/NCNF hybrid also exhibits high OER activity with an onset potential of 310 mV, an overpotential of 400 mV at a j of 10 mA cm − 2 and a small Tafel slope of 76 mV dec − 1 . The high catalytic activities of PtCo alloy for HER and OER originate from the 3D hierarchical structures, well-dispersed PtCo alloy, high conductivity of NCNF, protection from the carbon-encapsulated structure, and the introduction of nitrogen.
研究领域:
材料科学
·
纳米技术
·
电化学
·
能源化学
·
催化化学
·
功能材料
✓ 已验证
DOI
高影响因子
JOURNAL OF ELECTROANALYTICAL CHEMISTRY
·
2018
·
IF 3.235
Wangning Zhang,Waqar Uddin,Gang Hu,Lin Hu,Zhaohui Fang
A novel method for identification of four isomers of dihydroxynaphthalene (DHN) was reported by their different perturbation effects on a Briggs-Rauscher (BR) oscillating system. In the system, macrocyclic nickel (II) complex NiL(ClO 4 ) 2 is used as the catalyst, where the ligand L in the complex is 5,7,7,12,14,14‑hexemethyl‑1,4,8,11‑tetraazacyclotetradeca‑4,11‑diene. By putting equal amount of the same concentrations of four isomers (1,4‑dihydroxynaphthalene (1,4-DHN), 1,5‑dihydroxynaphthalene (1,5-DHN), 2,3‑dihydroxynaphthalene (2,3-DHN) and 2,7‑dihydroxynaphthalene (2,7-DHN)) into BR system, the system could or couldn't be perturbed, being reflected in quite different oscillating behaviors after addition of isomers. These four isomers were identified in their concentration range of 5.0 × 10 −6 to 2.5 × 10 −4 mol/L. An explanation of such perturbation mechanism is that, 1,4-DHN couldn't be oxidized by BR matrix, but 1,5-DHN, 2,3-DHN and 2,7-DHN could be oxidized by HOO to yield 5‑Hydrox‑1,4‑naphthoquinone, phthalic acid and 6,7‑dihydroxyperylene‑1,12‑quinone (DHPQ), respectively.
研究领域:
分析化学
·
物理化学
·
化学生物学
·
反应动力学
·
分子识别
✓ 已验证
DOI
高影响因子
ELECTROCHIMICA ACTA
·
2015
·
IF 4.504
K. Huang,K. Bi,J.C. Xu,C. Liang,S. Lin,W.J. Wang,T.Z. Yang,Y.X. Du,R. Zhang,H.J. Yang,D.Y. Fan,Y.G. Wang,M. Lei
Novel nanocomposites of spherical graphite-carbon encased tungsten carbide (GC-WC) are synthesized by solid state reaction with melamine and WO 3 as precursors under N 2 atmosphere. The diameters of the GC-WC composites range from 50 to 200 nm and the WC nanoparticles inside with an average size of ca. 15 nm distribute uniformly. The characterization results indicate that the GC-WC is composed of few layers of graphite carbon and WC nanoparticles with high crystallization and purity. Moreover, the electrocatalytic performance of GC-WC for the oxygen reduction reaction (ORR) in alkaline medium is further investigated by cyclic voltammetry (CV), rotating disk electrode (RDE) and chronoamperometry test with or without 3 M methanol. The results show that GC-WC has a considerable performance for ORR in the view of activity, stability and methanol tolerance, which may further used as proper supports for noble-metal based ORR catalysts in alkaline fuel cell . The synergetic interaction between the carbide nanoparticles and graphite carbon, which means that the surface graphite carbon layers are activated by WC nanoparticles for ORR and in turn protect inner WC from highly oxidizing environments has also been verified.
研究领域:
材料科学
·
纳米科技
·
电化学
·
能源材料
·
催化化学
✓ 已验证
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2020
·Vol. 36
·期 5
·816-820
·
IF 1.063
Chu Ning,Xu Shuping,Xu Weiqing
Two different kinds of configurations of 1,4-bis[2-(4-pyridyl)ethenyl]-benzene( trans -bpeb and cis -bpeb) were achieved, and a bpeb dimer was synthesized in dimethyl sulfoxide(DMSO). Compared with the previous work that synthesized the bpeb dimer or polymer in crystal with a template agent needed, the reaction occurred in a solution phase in the present method. A hand-held ultraviolet lamp(365 nm) with the power of 12 W and the Watt density of 0.35 mW/cm 2 can realize the photodimerization of bpeb, instead of the high-power mercury lamp in most previous studies. Unlike other 2+2 cycloaddition in liquid state using catalysts even noble metals, no catalysts were required here, which is cost-saving. Only the trans -pbeb can start the cycloaddition and the formation of the close J-aggregations of trans -pbeb in DMSO is a precondition for explaining the 2+2 photodimerization. The productivity for the 2+2 cycloaddition product was achieved as 55.6%.
研究领域:
有机化学
·
光化学
·
超分子化学
·
材料化学
·
合成方法学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS B-ENVIRONMENTAL
·
2020
·
IF 16.683
Hongguan Li,Jing Wang,Ruijuan Qi,Yongfeng Hu,Jing Zhang,Hongbin Zhao,Jiujun Zhang,Yufeng Zhao
Charge and spin manipulations of electrons are considered to be of great significance in boosting the catalytic activity of M N C electrocatalysts. However, to the best of our knowledge, most current studies focus only on the charge engineering, the interplay between spin and charge is not well understood, and the simultaneous manipulation of both charge and spin remains challenging. Herein, we show that the cooperative interplay between charge itineration and spin-polarization of electrons has a profound impact on the catalytic behavior through density functional theory (DFT) calculations for the first time. Following this concept, we report a Fe-Ni atomic pair as a superior bifunctional catalyst for high performance ORR and OER, with a very small potential difference (ΔE) of 0.691 V. We confirm that the coexistence of Fe 3d itinerant charge and moderate spin polarization (magnetic moment: 1.48 μ B ) is responsible for the superior functional catalytic activity for the Fe Ni atomic pairs.
研究领域:
电催化
·
材料化学
·
物理化学
·
纳米催化
·
能源材料
·
计算化学
✓ 已验证
DOI
高影响因子
JOURNAL OF ALLOYS AND COMPOUNDS
·
2018
·
IF 3.779
Hui Wang,Houzhen Chen,Hongjiao Wang,Lei Wu,Qixing Wu,Zhongkuan Luo,Fang Wang
The electrochemical performance of the lithium−oxygen (Li−O 2 ) batteries largely depends on the material and architecture of the catalytic cathode. In this paper, to avoid the parasitic reactions of carbon and binder with discharge products and reaction intermediates, we proposed an effective design of a free-standing catalytic cathode for Li−O 2 batteries. The FeCo 2 O 4 @Ni electrode consists of FeCo 2 O 4 nanosheets grown directly on nickel (Ni) foam. The resultant hierarchical macroporous/mesoporous structure provides sufficient space for the insoluble discharge product Li 2 O 2 and catalytically active sites for oxygen reduction reaction (ORR) and oxygen evolution reaction (OER). Consequently, the carbon- and binder-free self-supporting electrode has demonstrated a high discharge capacity with relatively low charge overvoltage and a better cycle performance than the corresponding carbon-based electrodes.
研究领域:
电化学
·
能源材料
·
纳米材料
·
电催化
·
储能技术
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）