RSC Advances
·
2017
·Vol. 7
·期 25
·15272-15277
·
IF 3.108
Yunhua Li,Juan Fu,Binghui Chen
Ni2P supported catalysts have extensively been studied for various hydrodeoxygenation (HDO) reactions. However, the main products are cyclohexane or cyclohexanol for lignin-derived compounds HDO over these catalysts. In this study, we investigate the catalytic conversion of anisole, phenol and guaiacol to benzene over Ni2P/SiO2 by probing the reaction conditions. The results show that a lower reaction temperature and higher H2 pressure favour the hydrogenation of these model chemicals to cyclohexane, whereas a higher reaction temperature and lower H2 pressure aid the generation of benzene. The cyclohexane and benzene yields are 89.8% and 96.0% at 1.5 MPa and 573 K and 0.5 MPa and 673 K, respectively. By eliminating the influence of internal and external diffusion, the low intrinsic activation energy of 58.2 kJ mol−1 is obtained, which explains the high catalytic activity. In addition, although guaiacol HDO has a low conversion due to the space steric effect of its substituents, it presents a similar reaction pathway to obtain anisole and phenol, which is dependent on reaction conditions. The long-run evaluation experiment shows that the activity and selectivity of anisole HDO to benzene changes slightly for 36 h.
研究领域:
化学工程
·
催化科学
✓ 已验证
DOI
高影响因子
ANALYTICAL AND BIOANALYTICAL CHEMISTRY
·
2022
·Vol. 414
·期 23
·6735-6741
·
IF 4.478
Wang Huaxin,Fu Ting,Ai Mimi,Liu Jinshui
A ratiometric fluorescent nanoprobe using carbon dots (CDs) and involving oxidation of terephthalic acid (TPA) induced by hydroxyl radicals (·OH) was developed for sensitively and selectively determining Fe 2+ ions. When Fe 2+ ions are added to the TPA@CDs/H 2 O 2 system, ·OH produced through the Fenton reaction oxidizes the non-fluorescent TPA to give 2-hydroxyl terephthalic acid, which fluoresces at 423 nm when excited at 286 nm. The ·OH and Fe 3+ produced quench CD fluorescence at 326 nm. The 2-hydroxyl terephthalic acid to CD fluorescence intensity ratio linearly increased as the Fe 2+ concentration increased in the range 0.5–50 μM, and the detection limit was 0.25 μM. The new assay is very selective because it involves dual-emission reverse change ratio fluorescence sensing, which can exclude matrix effects. The new nanoprobe was used to determine Fe 2+ concentrations in real water samples, and the recoveries were found to be acceptable. Graphical abstract Schematic of the ratiometric fluorometric method for determining Fe 2+ based on CDs and TPA
研究领域:
分析化学
·
环境科学
✓ 已验证
DOI
高影响因子
Polymer Chemistry
·
2021
·Vol. 12
·期 20
·3052-3059
·
IF 5.582
Lishan Li,Yiwen Li,Shuyuan Wang,Liandong Ye,Wei Zhang,Nianchen Zhou,Zhengbiao Zhang,Xiulin Zhu
The emergence of smart tubular vesicles has attracted increasing attention in the fields of life science and nanoengineering. Recent preliminary efforts have been put into fabricating kinds of smart tubular vesicles with different morphologies via the self-assembly of amphiphilic azobenzene-containing block copolymers. However, the detailed environmental effects on their self-assembly behaviors in solution remain uncharted. In this work, we carefully investigated several external factors that could influence the morphology formation and the transition of azobenzene-containing tubular vesicles, including the initial polymer concentration, the nature of common solvent, temperature, water addition rate, and irradiation with light of different wavelengths. The result showed that the morphological modulation of these tubular polymersomes was synergistically controlled by these external factors from both thermodynamics and kinetics aspects. This study could be helpful to understand and illustrate the morphology formation and modulation of smart tubular polymersomes.
研究领域:
生命科学
·
纳米工程
·
材料科学
✓ 已验证
DOI
高影响因子
OPTICAL AND QUANTUM ELECTRONICS
·
2021
·Vol. 53
·期 10
·1-8
·
IF 2.084
Li Chunfang,Zhang Hongyan,Xue Qihao,Li Dongxiang
Azobenzene compounds have been widely used in many fields and through their response to light they can be used to regulate the properties of ordered structures. In this paper, sub-micrometer colloidal SiO 2 spheres were prepared and azobenzene groups were grafted on the surface of SiO 2 microspheres. The SiO 2 microspheres grafted with azobenzene groups could self-assemble to form photosensitive photonic crystals, whose photonic bandgaps red-shifted as irradiated by UV light due to the structure change of the azobenzene groups.
研究领域:
材料科学
·
光学
✓ 已验证
DOI
高影响因子
Metals
·
2016
·Vol. 6
·期 8
·176
·
IF 1.574
Yongli Li,Zhuan Hu,Jinqing Kan
Zinc is widely used as a negative electrode material for batteries due to its excellent electrochemical properties. Zinc is prone to corrosion and the formation of zinc dendrites cause short circuits of the battery, which leads to reduced battery capacity and shortens the battery’s life, hindering its use in weak acidic electrolytes (for example, aqueous Zn-polyaniline batteries). The effects of carboxylates (sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium valerate, disodium malonate, and disodium succinate) and their concentrations on zinc electrode performance were studied with electrochemical methods to improve the zinc electrode activity for long-life Zn-polyaniline batteries. It was found that the ability of inhibiting corrosion of the zinc electrode is better in the aqueous electrolyte containing 0.2 M disodium malonate. The charge/discharge performance of a Zn-polyaniline battery electrodeposited with polyaniline on a carbon substrate is carried out in the aqueous electrolyte. the results show that the initial discharge specific capacity of the polyaniline in the Zn-polyaniline battery is as high as 131.1 mAh·g−1, and maintains a discharge specific capacity of 114.8 mAh·g−1and a coulombic efficiency over 92% after 100 cycles at a charge/discharge current density of 1 A·g−1in the voltage range of 1.5–0.7 V.
研究领域:
电化学
·
材料科学
✓ 已验证
DOI
高影响因子
CHEMICAL ENGINEERING JOURNAL
·
2016
·
IF 5.31
Zhifei Ma,Yu Yang,Yonghai Jiang,Beidou Xi,Tianxue Yang,Xing Peng,Xinying Lian,Kun Yan,Hongliang Liu
The reactivity of potassium persulfate (PP) in the degradation of 2,4-dinitrotoluene (2,4-DNT), with when iron and carbon as activators, is investigated. Effects of pH, persulfate concentration, and ionic strength on the degradation efficiency of 2,4-DNT by persulfate are studied in batch experiments, with simulated groundwater environmental conditions of no light, neutral pH and low temperatures (15 °C). The degradation of 2,4-DNT heightens and follows the pseudo-first-order kinetic model in the system comprising Fe/AC and S 2 O 8 2− . Addition of activated carbon (AC) increases the release of Fe 2+ to activate PP. When the concentration of persulfate is 100 mg/L, the 2,4-DNT degradation is the best at an initial pH of 2. The 2,4-DNT removal efficiency increases in the order of pH 2 > pH 9 > pH 3 > pH 5 > pH 11 > pH 7 in the Fe/AC + PP system. 2,4-DNT degradation in the presence of Cl − is slower in the first 100 min, but there is no obvious difference in degradation efficiency further on. This is most likely due to persulfate activation and Fe/AC reduction in this system. Meanwhile, the presence of bicarbonate ions inhibits the degradation of 2,4-DNT. A possible mechanism is proposed based on the reasons for the degradation of 2,4-DNT in the Fe/AC + PP system. Iron–carbon micro-electrolysis promotes micronmeter-sized iron to generate Fe 2+ . This study provides the design for an advanced, refractory organic matter-based oxidation technique for improved groundwater pollution remediation.
研究领域:
环境科学
·
化学工程
✓ 已验证
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2017
·
IF 2.323
Hai Liu,Xuemin Yu,Peng Cui,Midong Shi,Kun Xin,Yingmin Yu,Qingsong Li
Liquid–liquid equilibria provide fundamental data for designing and simulating a proper extraction process. The aim of this work is to extract cyclohexanone from wastewater using appropriate solvents. Liquid–liquid equilibrium experimental results were measured for water + cyclohexanone + benzene or methyl isobutyl carbinol ternary systems at 303.15 and 323.15 K under 101.3 kPa. The distribution ratios as well as selectivity values were calculated according to the experimental data to assess the extracting behaviors of the selected solvents. The selectivity value has a slight decrease with the increasing temperature from 303.15 to 323.15 K, which indicates that temperature has an adverse effect and the low temperature is more suitable for extraction. Besides, the consistency and reliability of the obtained experimental results were ascertained by applying both the Hand and Bachman equations. The obtained experimental tie-line data fitted well with the nonrandom two-liquid and universal quasichemical activity coefficient models, yielding root-mean-square deviation (rmsd) values as low as 0.17 and 0.16 for the two models, respectively.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Tao Chen,Tingting Ye,Jie Zhu,Guoqing Li,Zhe Chen,Menglin Xie,Yu Zhou,Jun Wang
Metal-free carbon materials have attracted growing attention in terms of green and sustainable catalysis processes that could avoid potential metal leaching but usually suffered from inferior activity to metal-loaded counterparts. In this work, we constructed an efficient carbon catalyst via hydrothermal carbonization of biomass-derived feedstock glucose under relatively low temperature (180 °C). The resultant carbon material possessing abundant surface oxygen species effectively catalyzed the benzene hydroxylation with dioxygen (O 2 ), a desirable but very difficult alternative process for producing the important bulk chemical phenol . A considerably high phenol yield of 13.1% was achieved within 4 h, a reaction time much shorter than all the previous metal-free catalysts and even shorter than most efficient metal-based catalysts. The fast reaction is determined by the formation of small-sized primary carbon particles with the abundant surface oxygen species, for which the adsorption enhancing effect in the media of this heterogeneous process was experimentally evidenced.
研究领域:
催化化学
·
绿色化学
✓ 已验证
DOI
高影响因子
RSC Advances
·
2017
·Vol. 7
·期 21
·12805-12811
·
IF 3.108
Chunfeng Mao,Rongxiang Zhao,Xiuping Li,Xiaohan Gao
A series of deep eutectic solvents (DESs) of ChCl/XCF3SO3H (X from 1.0 to 2.0) were synthesized by stirring a mixture of choline chloride (ChCl) and trifluoromethanesulfonic acid (CF3SO3H) at room temperature. The DESs were characterized by Fourier transform infrared (FT-IR) and 1H nuclear magnetic resonance (1H NMR). The oxidative desulfurization of model oil was investigated using ChCl/1.5CF3SO3H as a catalyst and extraction agent, and H2O2 as the oxidant. Some reaction parameters such as type of DES, molar ratio of CF3SO3H and ChCl in DESs, H2O2 dose, reaction temperature, DES dose and type of sulfur compound were investigated. Under the optimum conditions, the removal rate of dibenzothiophene (DBT) and 4,6-dimethyldibenzothiophene (4,6-DMDBT) can reach up to 98.65% and 96.8%, respectively. After five recycling runs, the removal rate of DBT can still reach 97.16%.
研究领域:
化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
ENZYME AND MICROBIAL TECHNOLOGY
·
2017
·
IF 2.502
Ren-Chao Zheng,Xiao-Ling Tang,Hui Suo,Li-Lin Feng,Xiao Liu,Jian Yang,Yu-Guo Zheng
Tyrosine phenol-lyase (TPL) catalyzes the reversible cleavage of l -tyrosine to phenol, pyruvate and ammonia. When pyrocatechol is substituted for phenol, l -dihydroxyphenylalanine ( l -DOPA) is produced. The TPL-catalyzed route was regarded as the most economic process for l -DOPA production. In this study, a novel TPL from Fusobacterium nucleatum ( Fn -TPL) was successfully overexpressed in Escherichia coli and screened for l -DOPA synthesis with a specific activity of 2.69 U mg −1 . Fn -TPL was found to be a tetramer, and the optimal temperature and pH for α, β-elimination of l -tyrosine was 60 °C and pH 8.5, respectively. The enzyme showed broad substrate specificity toward natural and synthetic l -amino acids. Kinetic analysis suggested that the k cat / K m value for l -tyrosine decomposition was much higher than that for l -DOPA decomposition, while Fn -TPL exhibited similar catalytic efficiency for synthesis of l -tyrosine and l -DOPA. With whole cells of recombinant E. coli as biocatalyst, l -DOPA yield reached 110 g L −1 with a pyrocatechol conversion of 95%, which was comparable to the reported highest level. The results demonstrated the great potential of Fn -TPL for industrial production of l -DOPA.
研究领域:
生物化学
·
酶学
·
微生物学
✓ 已验证
DOI
高影响因子
JOURNAL OF HAZARDOUS MATERIALS
·
2020
·
IF 9.038
Qing Zheng,Nannan Wu,Ruijuan Qu,Gadah Albasher,Wanming Cao,Beibei Li,Nouf Alsultan,Zunyao Wang
4- tert -butylphenol (4-tBP) is a phenolic endocrine disrupting chemical that has attracted great attention due to its wide occurrence, environmental persistence, and possible toxic effects. In this study, we systematically investigated the transformation of 4-tBP in ferrate (VI) oxidation process. The second-order reaction rate constant ( k app ) of Fe(VI) with 4-tBP decreases with solution pH, and the k app value was determined as 295 M −1 ·s −1 at pH 8.0. The removal efficiency of 4-tBP was slightly decreased by Mg 2+ and HCO 3 – , while accelerated at varying degrees by the presence of Cu 2+ and humic acid. Product analysis revealed that 4-tBP was mainly transformed into hydroxylation products, benzene-ring cleavage products, dimers and higher polymerization products via oxygen atom transfer, ring-opening of the benzene ring and radical coupling reaction. Furthermore, initial reactions of 4-tBP were rationalized by theoretical analysis of atom partial charges, frontier electron densities, and spin densities. Nearly complete removal of 4-tBP (20 μM) was achieved after 5 min of reaction in both ultrapure water and natural waters, demonstrating the feasibility of this Fe(VI) oxidation method in treating phenols-contaminated waters.
研究领域:
环境科学
·
化学动力学
✓ 已验证
DOI
PubMed
高影响因子
FUEL
·
2018
·
IF 4.908
Wenwu Zhou,Yanan Zhang,Xiujuan Tao,Yasong Zhou,Qiang Wei,Sijia Ding
The effects of gallium (Ga) modification on mesoporous Al 2 O 3 (MA) were studied, focusing on the morphology changes of the active phases and the application as catalyst support for catalytic performances for dibenzothiophene (DBT) hydrodesulfurization (HDS). MA samples with wide mesopore size distribution (MA-W), double mesopore size distribution (MA-D) and single mesopore size distribution (MA-S) were synthesized from the boehmite sol–gel via a hydrothermal synthesis method. The synthesized MA-S sample was modified with Ga 2 O 3 , and the corresponding sulfide NiMo supported catalysts were prepared. The as-synthesized samples were characterized by XRD, N 2 physisorption, NH 3 -TPD, H 2 -TPR, HRTEM and XPS. Superior catalytic performance was observed over the NiMo/MA-S-2Ga catalyst due to the moderate interaction between the active metals and the supports; the superior morphology for Ni promoted MoS 2 crystals, the highest sulfidation degree, the largest proportion of the NiMoS phase and the enhanced hydrogenation activity caused by the introduction of Ga species.
研究领域:
催化材料
·
化学工程
·
能源化学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）