INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
·
2023
·
IF 4.2
Yiyun Wang,Xinli Li,Zhi Chen,Kai Ma,Congming Tang
This work reported the coupling reaction of lactic acid (LA) to produce pyruvic acid (PyA) and propionic acid (PA) simultaneously over defect-rich MoS2 nanosheets. The process intensification linked to dehydrogenation of LA and hydrodeoxygenation of LA brings about the advantage that is not supplied additionally with oxygen and hydrogen, achieving a green and safe route. The defected structure is characterized by high-resolution transmission electron microscopy (HRTEM) and positron annihilation lifetime spectroscopy (PALS), which promotes the catalytic performance for the coupling reaction of LA. To fully understand the importance of the defected structure, the catalytic performance of defect-free MoS2 is also evaluated. It is found that the PyA/PA ratio is less than 1 and acetaldehyde selectivity is relatively high, suggesting that the produced hydrogen from the dehydrogenation of LA is insufficient for hydrodeoxygenation of LA over defect-free MoS2, and the difference of hydrogen comes from the side reactions of decarbonylation and decarboxylation of LA. Unlike the defect-free MoS2, the dehydrogenation of LA over the defect-rich MoS2 can provide sufficient hydrogen for hydrodeoxygenation of LA, so that the side reactions are drastically weakened. The widened interplanar spacing can fully expose the defect and the LA reactant molecule is more accessible to defective sites, which can endow a better catalytic activity. Surface hydrophilicity can improve adsorption and transfer, and better activity is observed over the defect-rich MoS2 and widened defect-rich MoS2. At 300 °C and a LA LHSV of 2.6 h–1 under an inert atmosphere, the catalyst offers a satisfactory total selectivity to pyruvic acid and propionic acid of about 85%, and the molar ratio of pyruvic acid/propionic acid is 1.1.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
·
2021
·
IF 11.236
Xiaoxue Pan,Junyan Wei,Mengting Zou,Jing Chen,Ruijuan Qu,Zunyao Wang
We systemically investigated the transformation behavior of 2,4-dichlorophenol (24-DCP) in seven different reaction systems including KMnO 4 , heat/PS, O 3 , UV, Fenton, NaClO and K 2 FeO 4 treatment. The results revealed that complete removal of 24-DCP could be reached in minutes, especially for Fe(VI), KMnO 4 , NaClO, Fenton and O 3 system. A total of 41 products were identified by LC-MS, and 10 of them were validated using commercial and self-synthesized standards. Hydroxyl substitution and coupling reactions were commonly observed in the studied systems. Meanwhile, extra routes such as sulfate substitution, (de)chlorination and direct oxidation were also involved for certain oxidation methods. Comparisons showed that a high degree of chlorination (>90%) occurred for NaClO system, while coupling products accounted for ~45% of the removed 24-DCP under PS oxidation. Moreover, low mineralization degree together with high aquatic toxicity was attributed to the occurrence of coupling reaction, which was possibly related to the redox potential of the main oxidative species. Considering the low abundance of coupling products and the gentle reaction condition, UV irradiation is a better option for 24-DCP removal in water and wastewaters. These findings can deepen our understanding on the transformation process of 24-DCP and provide some useful information for the environmental elimination of substituted phenols.
研究领域:
环境科学
·
化学
✓ 已验证
DOI
高影响因子
APPLIED SURFACE SCIENCE
·
2024
·
IF 6.3
Songhao Yu,Guifen Tian,Liduan Li,Fei Wang,Kefeng Wang,Junyu Lei,Haijun Hao,Qinghong Xu
TpFO-PA, a novel spherical hollow mesoporous polyamide, was firstly synthesized by the reaction among 1,3,5-tris(4-aminophenyl)benzene (TAPB), furylamine and oxalyl chloride in using silica-gel nanoparticle as hard template, and the composite Cu(I)@TpFO-PA with high catalytic activities in C-N coupling reactions between (hetero)aryl bromide and (hetero)aryl amines under mild conditions was prepared basing on presence of N in the framework. A maximum activity of the catalyst with yield of C-N coupling product were about 311.9 g (product) /mol Cu(I) ·h and 95 % respectively, and the activity could be maintained at least 5 times after the catalyst was reused. The composite Cu(I)@TpFO-PA is a few heterogeneous catalysts reported in catalyzing coupling reaction between aromatic amines and brominated aromatic compounds.
研究领域:
化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2022
·Vol. 12
·期 10
·1170
·
IF 4.501
Zongyang Liu,Jie Li,Yuan Tan,Luyao Guo,Yunjie Ding
The direct conversion of biomass-derived ethanol to high-valued-added chemicals has attracted widespread attention recently due to the great economic and environmental advantages. In the present study, the conversion of bioethanol through the Guerbet coupling process was studied in a fixed-bed reactor for MgAlOxand ZnAlOxmixed-oxides supported Cu catalysts. From the results, Cu adding into the system greatly enhance the dehydrogenation of ethanol and increase the H-transfer in the course of Guerbet coupling process. Simultaneously, the porous mixed-oxides provide the acid-base property of the catalysts for intermediate transformation. Notably, for Cu/MgAlOx, the main product of ethanol conversion is butanol, but for Cu/ZnAlOx, the primary product is ethyl acetate. Characterizations such as X-ray diffraction (XRD), high-resolution transmission electron microscopy (HRTEM), X-ray photoelectron spectroscopy (XPS), in situ diffuse reflectance infrared Fourier transform spectroscopy (DRIFTS) and CO2temperature programmed desorption (TPD) were carried out to evaluate the structure and property of the catalysts. In combination with the catalytic performances with the characterization results, the synergistic catalytic effect between metal sites and acid-base sites were elaborated.Keywords:Cu catalyst;mixed-oxide;bioethanol;Guerbet coupling;butanol
研究领域:
催化化学
·
可再生资源化学
✓ 已验证
产品关联
DOI
高影响因子
Nanoscale
·
2017
·Vol. 9
·期 10
·3568-3575
·
IF 7.367
Hong Zhi Zhang,Rong Sheng Li,Peng Fei Gao,Ni Wang,Gang Lei,Cheng Zhi Huang,Jian Wang
Gold nanorods (GNRs) have opened up promising applications based on their reshaping, due to the fact that a tiny change in shape or size could directly lead to optical changes. Herein, we report chemical reshaping of GNRs induced by the coupling reaction between Au, ferric chloride and thiourea. In the coupling reaction, Fe3+ oxidizes the GNRs to yield Au(I), which complexes with the thiourea ligand, lowering the Gibbs free energy of the gold species and promoting the reaction equilibrium to enable the chemical reshaping of the GNRs. This coupling reaction process was monitored using a light-scattering dark-field microscopy (DFM) imaging technique and scanning electron microscopy (SEM). The light scattering underwent a colour change from bright red to yellow and finally to green, and the GNRs underwent a morphological change from rod-shaped to fusiform and finally to spherical, which is somewhat different from the results of other chemical etching processes of GNRs. It is believed that the coupling reaction induced chemical reshaping of GNRs not only provides an alternative way to monitor the coupling reaction, but also offers a facile way to obtain a desirable GNR morphology, which is important for the preparation of fusiform nanostructures.
研究领域:
纳米材料科学
·
光学成像
·
化学动力学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Journal of Materials Chemistry A
·
2024
·
IF 10.7
Rui Li,Yingdan Ye,Yibin Zhang,Huaiyuan Zhao,Weichen Du,Zhaoyin Hou
Dehydrogenation of cyclohexanol to cyclohexanone is a vital step in manufacturing nylon; however, this endothermic reaction is unfavourable at low temperatures. In this work, a high-entropy oxide (Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO) was synthesized from a well-structured Cu0.75Zn0.15Mg7.1Al1Sc1(OH)20CO3 layered double hydroxide. Characterization results disclosed that Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO possesses a large specific surface area (157 m2 g−1), enhanced basicity and high Cu dispersion in the framework of HEO (74.0%). The reduced Cu0.75Zn0.15Mg7.1Al1Sc1O11-HEO catalyst was highly active and stable in the dehydrogenation of cyclohexanol compared with Cu-based catalysts prepared using binary, ternary, and quaternary mixed metal oxides. More interestingly, the conversion of cyclohexanol could be enhanced when acetone was used as the solvent and/or hydrogen acceptor. Thus, it was confirmed that the addition of acetone can enhance the yield of cyclohexanone and simultaneously result in the hydrogenation of acetone to isopropanol.
研究领域:
化学工程
·
催化科学
✓ 已验证
产品关联
DOI
高影响因子
TALANTA
·
2024
·
IF 5.6
Lichen Gou,Ling Li,Siqi Wei,Yunfei Tian,Xiandeng Hou,Li Wu
Herein, the surface-enhanced Raman scattering (SERS) platform was combined with an azo coupling reaction and an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes for the detection of histamine. The praseodymium oxide on aluminum alloy was successfully synthesized by the rare-earth-salt-solution boiling bath method and modified by stearic acid. Its surface exhibits a water contact angle (WCA) of 125.0°. Through the azo derivatization reaction with 3-amino-5-mercapto-1,2,4-triazole (AMTA) diazonium salts, histamine can be converted into the derivatization product with higher Raman activity. The mixture of the derivatization product and β-cyclodextrin-modified Ag nanoparticles (β-CD-AgNPs) were dropped onto the surface of an aluminum alloy covered with a hydrophobic layer of praseodymium oxide and stearic acid complexes, and dried for SERS measurement. The intensity ratio between the SERS peaks at 1246 cm −1 and 1104 cm −1 (I 1246 /I 1104 ) of the derivatization product was used for the quantification of histamine. Under the selected conditions, the limit of detection (LOD) and the limit of quantification (LOQ) for this method were 7.2 nM (S/N = 3) and 24 nM (S/N = 10), respectively. The relative standard deviation (RSD) of this method for the determination of 1 μM histamine was 6.1 % (n = 20). The method was also successfully used for the determination of histamine in fish samples with recoveries ranging from 92 % to 111 %. The present method is simple, sensitive, reliable, and may provide a new approach for preparing the composite hydrophobic layer that can enhance SERS signals through hydrophobic condensation effect. Meanwhile, it may have a promising future in the determination of small molecular compounds containing an imidazole ring.
研究领域:
分析化学
·
食品科学
·
生物医学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
HIGH PERFORMANCE POLYMERS
·
2014
·
IF 1.09
Yewei Xu,Yi Sun,Yonglin Lei,Jichuan Huo,Lin Zhang
Poly(N-arylenebenzimidazole ketone ketone pyridine)s have been prepared via N–C coupling reaction that removed the N–H sites from the novel bis(benzimidazoyl) derivatives with activated aromatic difluorides in sulfolane. The reaction was carried out at 210°C in the presence of anhydrous potassium carbonate. The structures of the polymers were characterized by means of Fourier transform infrared and proton nuclear magnetic resonance spectroscopies and elemental analysis. All resulting polymers showed essentially amorphous patterns. Differential scanning calorimetry and thermogravimetric measurements showed that the polymers had high glass transition temperatures (>179°C), good thermostability, and high decomposition temperatures (>401°C). These novel polymers also showed easy solubility.
研究领域:
高分子化学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
Journal of Cleaner Production
·
2018
·
IF 5.651
JiaKai Mao,Jia Li,Zhengming Xu
The wider application of lithium ion batteries brings more production of spent ones to be recovered. There is a pyrometallurgical treatment by getting negative and positive materials burning together. The paper provides theoretical analysis and support for the feasibility of the treatment. Positive material graphite's burning and pyrolysis of negative material lithium cobalt oxide can make up as a coupling reaction, decreasing the decomposition temperature of lithium cobalt oxide from 1426 K to 1173 K. From the point view of crystal structure, the stronger attraction of graphite to oxygen than lithium and cobalt make oxygen octahedrons insides lithium cobalt oxide unstable to break down. We definite the phenomenon as the oxygen octahedrons collapsing model. Coupling reaction theory and crystal structure analysis indicate that graphite does promote the pyrolysis of lithium cobalt oxide. The study can guide industrial application to recover lithium ion batteries whose structure is similar to oxygen octahedrons at a comparatively low temperature.
研究领域:
冶金学
·
材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF LUMINESCENCE
·
2024
·
IF 3.3
Ziting Yuan,Zhiping Shi,Xi Nian,Bingbing Li,Kai Li,Liqiong Liao
Ellagic acid (EA), a natural polyphenol, features a highly organized planar structure with an extensive sp 2 carbon-conjugated area, making it favorable for light energy absorption and fluorescent emission. However, this planar structure can easily aggregate through π-π stacking, leading to aggregation-caused quenching of fluorescence. In this research, aniline-doped ellagic acid (EAAn 2 ) was successfully synthesized via a C-N coupling reaction to address this issue. The fluorescence properties of EAAn 2 in various organic solvents were thoroughly investigated. Compared to EA, EAAn 2 exhibited a red shift in fluorescence emission, primarily revealing yellow fluorescence instead of the green fluorescence of EA. Moreover, the fluorescence intensity and the concentration at which aggregation-caused quenching occurs for EAAn 2 were substantially improved due to the two grafted aniline molecules. EAAn 2 was utilized as a molecular fluorescent probe in DMSO to detect three kinds of metal ions: alkali and alkaline-earth metal ions, transition metal ions, and post-transition metal ions, using EA as a control. It was found that the combination of EAAn 2 with these metal ions exhibited stronger fluorescence intensity than EA and effectively resisted the blue shift in fluorescence emission due to aniline doping. Based on these results, Mg 2 ⁺ ions could be clearly distinguished from other alkali and alkaline-earth metal ions by differences in their fluorescence emission, as could Cr 2 ⁺ ions among transition metals. This research effectively enhances the fluorescence properties of EA through C-N coupling and demonstrates its greater potential in the detection of metal ions, providing fundamental and valuable information for future fluorescent applications.
研究领域:
化学
·
材料科学
·
分析化学
✓ 已验证
产品关联
DOI
高影响因子
CATALYSIS COMMUNICATIONS
·
2017
·
IF 3.33
Xi Zheng,Jiping Ma,Min Wang,Song Shi,Zhiqiang Sun,Jie Xu
Coupling reaction of cyclohexyl hydroperoxide (CHHP) decomposition and cyclohexane oxidation in the process of catalytic decomposition of CHHP was identified via cyclopentane instead of cyclohexane used as solvent. A method was established to evaluate this coupling reaction. Based on this method, it can be accurately distinguished the product of cyclohexanol and cyclohexanone (K/A oil) derived from whether decomposition of CHHP or oxidation of cyclohexane. The established method is of great significance to the further study of the coupling reaction.
研究领域:
化学工程
·
催化化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF COLLOID AND INTERFACE SCIENCE
·
2024
·
IF 9.4
Yifei Ye,Yuanyuan Cui,Li Yang,Jiaxu Zhang,Jianmin Sun
A novel external-skeleton B-containing ionic liquid modified SBA-15 catalyst BBN-Imi-SBA-15-I (BBN denotes borabicyclo[3.3.1]nonane, Imi represents imidazolium ionic liquid) was successfully constructed by a post-modification method for efficiently catalyzing CO 2 -epoxide coupling reaction under both metal- and solvent-free conditions. 5BBN-Imi-SBA-15-I (5 refers to the molar ratio of Si to B), thanks to its synergistic effects of Lewis acid, weak base sites from tertiary amine and quaternary ammonium, hydrogen bond group and nucleophilic group, displayed good catalytic activity with 97 % product yield and 99 % selectivity at 100 °C, 2 MPa in the absence of cocatalyst. The obtained catalyst demonstrated good recyclability during six consecutive catalytic runs, also presented generality for various mono-substitute epoxides. Through in-situ NH 3 diffuse reflectance infrared Fourier transform spectroscopy (NH 3 -DRIFTS) characterization, the Lewis acidity of organo-boron was verified. Besides, kinetics research also proved the positive effect of multiple active components on efficient catalysis under milder conditions over SiO 2 -based metal-free catalysts.
研究领域:
材料科学
·
催化化学
✓ 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）