CATALYSIS LETTERS
·
2020
·Vol. 151
·期 3
·901-908
·
IF 2.482
Wu Yuting,Yang Long,Wu Bo,Li Jie,Liu Binyao,Ke Gaili,Dong Faqin,Zhou Yong,He Huichao
It has been reported that β -MnO 2 has photocatalytic activity for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols. Nevertheless, it is hard to exclude the possibility that the oxidative-coupling of 2-naphthols is initiated by β -MnO 2 catalysis in dark due to the insufficient investigations in the related reports. In the present work, the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols with different phases MnO 2 catalysis in dark and under visible-light irradiation were systematically investigated. The results revealed that the oxidative-coupling of 2-naphthols is jointly initiated by MnO 2 catalysis and O 2 -oxidation, not by MnO 2 photocatalysis. Among the α -MnO 2 , β -MnO 2 , γ -MnO 2 and δ -MnO 2 catalysis, β -MnO 2 catalysis has the optimal performance, its selectivity for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols is close to 100%, and its catalytic capacity could be well retained after multiple using. Our findings provide comprehensive and accurate understanding the catalytic role of MnO 2 for the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols. Graphic In the present work, the oxidative-coupling of 2-naphthols into 1,1′-bi-2-naphthols was proved to be jointly initiated by MnO 2 catalysis and O 2 -oxidation, not by MnO 2 photocatalysis. β -MnO 2 has the optimal catalytic activity for the oxidative-coupling of 2-naphthols relative to α -MnO 2 , γ -MnO 2 and δ -MnO 2 .
研究领域:
催化化学
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有机合成
·
材料化学
·
物理化学
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纳米催化
✓ 已验证
DOI
高影响因子
JOURNAL OF RARE EARTHS
·
2013
·
IF 1.363
Hongzhen XIE,Guanzhong LU
Five lanthanide complexes of Ln 2 (dpdc) 2 (tpy) 2 (NO 3 ) 2 (H 2 O) 2 [Ln=La ( 1 ), Ce ( 2 ), Pr ( 3 ), Sm ( 4 ), Gd ( 5 ), H 2 dpdc=2,2’-biphenyldicarboxylic acid and tpy=2,2′:6′,2″-terpyridine] were prepared at room temperature and characterized by X-ray diffraction, FT-IR and thermo-gravimetric analysis. The results showed that complexes 1–5 were isostructural and consisted of dinuclear units [Ln 2 (dpdc) 2 (tpy) 2 (NO 3 )(H 2 O) 2 ] bridged by two dpdc 2− ligands. The dinuclear units with strong intramolecular hydrogen bonds were assembled into 2D supramolecular layers by the weak π … π staking interactions between pyridine rings of tpy. The TG analysis showed that the complexes 1 – 5 behaved higher thermal stability with no mass loss at < 320 °C. The lanthanide contraction effect and the solid state luminescence properties of complexes 1 – 5 were also investigated. The luminescence emission spectra of complexes 1 – 5 exhibited ligands emission bands and complex 3 and 4 had no typical emission in the visible region.
研究领域:
化学
·
材料科学
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产品关联
DOI
高影响因子
CHROMATOGRAPHIA
·
2019
·Vol. 82
·期 10
·1579-1583
·
IF 1.552
Lou Chunli,Zheng Mengmeng,Xu Yao,Shen Yuting,Kang Jingwu
A sensitive method was developed for detecting 2,2′-azobis(2-amidinopropane) dihydrochloride in polyvinylpyrrolidone by capillary electrophoresis with indirect UV detection. The detection sensitivity was improved significantly using the field-amplified sample injection technique. The background electrolyte was composed of 25 mM imidazole-HCl solution (pH 4.0), in which imidazole acted as the cation probe for the indirect detection at UV 214 nm. Effects of the experimental parameters including pH, the concentration of imidazole as well as the sample injection time on sample preconcentration were investigated and optimized. Under the optimized conditions, baseline separation of 2,2′-azobis(2-amidinopropane) ion with other ions in the polyvinylpyrrolidone samples was achieved within 8 min. The RSD% for the repeatability of the migration time and the peak area were determined as 0.95% and 3.47%, respectively. The limit of detection (LOD, S / N = 3) and the limit of quantitation (LOQ, S / N = 10) were determined as 1.11 × 10 −5 M and 2.77 × 10 −5 M, respectively. The measured recovery at three concentration levels was in the range of 101–104%. This method was successfully applied to detect 2,2′-azobis(2-amidinopropane) in the commercial polyvinylpyrrolidone samples.
研究领域:
分析化学
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制药工程
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产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2021
·
IF 2.694
Qing Yi,Wei-Peng Chen,Xiang-yang Zhang,Yan-Yang Wu,Bin Wu,Kui Chen,Li-Jun Ji
The isobaric vapor–liquid equilibrium (VLE) data of 2-phenylethanol (2-PE) + 2-ethylphenol (2-EP), 1-phenyl-2-propanol (1,2-PP) + 2-ethylphenol (2-EP), 2-phenylethanol (2-PE) + 1-phenyl-2-propanol (1,2-PP) and 2-phenyl-1-propanol (2,1-PP) + 2-ethylphenol (2-EP) were measured by a modified Rose type still under 101.3 kPa. Both the Fredenslund test and Redlich–Kister area test were employed to verify the consistency of the experimental data. Besides, the experimental isobaric VLE data were correlated by Wilson, nonrandom two-liquid, and universal quasi-chemical models, and the corresponding parameters were obtained accordingly. All three models showed good agreement with the experimental data, and among which the Wilson model performed slightly better than the others.
研究领域:
化学工程
·
物理化学
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DOI
高影响因子
JOURNAL OF DAIRY SCIENCE
·
2023
·
IF 3.5
Yanmei Xi,Sana Ikram,Tong Zhao,Yiwei Shao,Ruirui Liu,Fuhang Song,Baoguo Sun,Nasi Ai
ABSTRACT Flavor sensation is one of the most prevalent characteristics of food industries and an important consumer preference regulator of dairy products. So far, many volatile compounds have been identified, and their molecular mechanisms conferring overall flavor formation have been reported extensively. However, little is known about the critical flavor compound of a specific sensory experience in terms of oxidized off-flavor perception. Therefore, the present study aimed to compare the variation in sensory qualities and volatile flavors in full-fat UHT milk (FFM) and low-fat UHT milk (LFM) samples under different natural storage conditions (0, 4, 18, 25, 30, or 37°C for 15 and 30 d) and determine the main component causing flavor deterioration in the FFM and LFM samples using sensory evaluation, electronic nose, and headspace solid-phase microextraction-gas chromatography-mass spectrometry (HS-SPME-GC-MS). In addition, the Pearson correlation between the volatile flavor components and oxidative off-flavors was analyzed and validated by sensory reconstitution studies. Compared with the LFM samples, the FFM samples showed a higher degree of quality deterioration with increased storage temperature. Methyl ketones of odd carbon chains (i.e., 2-heptanone, 2-nonanone, 2-undecanone, 2-tridecanone, and 2-pentadecanone) reached a maximum content in the FFM37 samples over 30 d storage. The combined results of the Pearson correlation and sensory recombination study indicated that 2-heptanone, 2-nonanone, and 2-undecanone conferred off-flavor perception. Overall, the present study results provide potential target components for detecting and developing high-quality dairy products and lay a foundation for specific sensory flavor compound exploration in the food industry.
研究领域:
食品科学
·
感官评价
·
分析化学
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产品关联
DOI
PubMed
高影响因子
MATERIALS AND STRUCTURES
·
2023
·Vol. 56
·期 1
·1-15
·
IF 3.8
Song Yufeng,Zhang Yi,Shen Siyi,Pan Chenyu,Yan Dongming,Wang Zhiguang,Wang Su,Ruan Shaoqin
This study aims to explore the effects of different Ca(OH) 2 contents on the mechanical performance and corrosion behaviors of steel in Calcium sulfoaluminate (CSA) cement, where compressive strength, corrosion potentials of reinforcements, corrosion current density, pH of pore solution as well as mortar resistivity of CSA/Ca(OH) 2 mortar were researched, and the corrosion behaviors were further interpreted by the clarification of hydration phases through microstructural analyses. The initial results highlighted the positive effects of using adequate Ca(OH) 2 (~ 6%) in CSA mortar in terms of strength, yet its excessive addition could delay the subsequent hydration reaction of CSA. Meanwhile, with an increased quantity of Ca(OH) 2 , the amount of some hydration phases, such as Al(OH) 3 reduced, resulting from their reaction with Ca(OH) 2 . Finally, the corrosion current density increased with the reduced mortar resistivity when the reinforcement in CSA/Ca(OH) 2 system was corroded, and their relationship was also provided in this study.
研究领域:
建筑材料学
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腐蚀科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL AND ENGINEERING DATA
·
2013
·
IF 2.004
Chao Guo,Shaoyun Chen,Yongchun Zhang
Solubility measurements of carbon dioxide (CO2) in aqueous 2-(2-aminoethylamino)ethanol (AEEA, 15 wt %), AEEA + N-methyldiethanolamine (MDEA, 5, 10 wt %), and AEEA + 2-amino-2-methyl-1-propanol (AMP, 5, 10 wt %) solutions as CO2 absorbents were performed at CO2 partial pressure from (0.8 to 800) kPa and temperatures of (303, 313, and 323) K. With increasing the MDEA/AMP amount to AEEA, CO2 loading of the absorbents decreased, while the absorption rate increased. At low CO2 partial pressure (< 30 kPa), the loading of AEEA + AMP was higher than that of AEEA + MDEA, while at high CO2 partial pressure (> 100 kPa), the loading of AEEA + AMP was lower than that of AEEA + MDEA at the same concentration. Furthermore, the absorption rate was in the order AEEA + AMP > AEEA + MDEA > AEEA.
研究领域:
化学工程
·
环境科学
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产品关联
DOI
高影响因子
APPLIED PHYSICS A-MATERIALS SCIENCE & PROCESSING
·
2018
·Vol. 124
·期 7
·1-11
·
IF 1.604
Yao Hanyu,Shen Honglie,Tang Quntao,Yang Nannan,Zhai Zihao,Li Yufang
NaY(WO 4 ) 2 : Er 3+ phosphors with various doping concentrations of [Er 3+ ]/([Er 3+ ]+[Y 3+ ]) (0, 5, 7, 10, 12, 15%) were successfully synthesized by high-temperature solid-state reaction. X-ray diffraction (XRD) measurement demonstrated the presence of tetragonal-phase NaY(WO 4 ) 2 phosphors and Fourier transform infrared (FT-IR) spectra showed a strong υ 3 stretching vibration mode of WO 4 2− , indicating the good crystallization of the phosphors. Well-crystallized phosphors showed a fine morphology with particle sizes of 0.8–10 µm by scanning electron microscope (SEM). Under excitation of 980 nm laser, Er 3+ -doped phosphors exhibited strong green emissions centered at 527 and 549 nm in addition to a 665 nm emission band in the red region, which were assigned to the 2 H 11/2 , 4 S 3/2 → 4 I 15/2 and 4 F 9/2 → 4 I 15/2 transitions, respectively. When the doping concentration was 10%, the intensities of green and red emissions reached their maximum values, stronger than that in 5% Er 3+ doped one by 13 times. The double-logarithm plot of the upconversion (UC) emission intensity to the excitation power for different Er 3+ doping concentrations depicted that at least two infrared photons were involved for every emitted green and red photon. UC emission intensity changing with temperature displayed different trends for the phosphors with different Er 3+ concentrations. The enhancement for green emission band centered on 549 nm could reach 50 times at 30 K in sample with 5% Er 3+ concentration. Under excitation by 355 nm laser, all the phosphors showed a strong PL emission band at 430 nm, while green luminescence band locating from 540 to 570 nm was only observed in 7, 10, and 12% Er 3+ -doped phosphors, which was ascribed to 4 S 3/2 → 4 I 15/2 transition.
研究领域:
材料科学
·
光学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF SOLID STATE CHEMISTRY
·
2018
·
IF 2.179
Yun-Xiang Ma,Ya-Ping Gong,Chun-li Hu,Jiang-Gao Mao,Fang Kong
Three new d 10 transition metal selenites containing PO 4 tetrahedron, namely, Cd 7 (HPO 4 ) 2 (PO 4 ) 2 (SeO 3 ) 2 ( 1 ), Cd 6 (PO 4 ) 1.34 (SeO 3 ) 4.66 ( 2 ) and Zn 3 (HPO 4 )(SeO 3 ) 2 (H 2 O) ( 3 ), have been synthesized by hydrothermal reaction . They feature three different structural types. Compound 1 exhibits a novel 3D network composed of 3D cadmium selenite open framework with phosphate groups filled in the 1D helical tunnels. The structure of compound 2 displays a new 3D framework consisted of 2D cadmium oxide layers bridged by SeO 3 and PO 4 groups. Compound 3 is isostructural with the reported solids of Co 3 (SeO 3 ) 3-x (PO 3 OH) x (H 2 O) when x is equal to 1.0. Its structure could be viewed as a 3D zinc oxide open skeleton with SeO 3 and HPO 4 polyhedra attached on the wall of the tunnels. They represent the only examples in metal selenite phosphates in addition to the above cobalt compounds. Optical diffuse reflectance spectra revealed that these solids are insulators, which are consistent with the results of band structure computations based on DFT algorithm.
研究领域:
无机化学
·
材料科学
·
固体化学
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产品关联
DOI
高影响因子
CHEMICAL RESEARCH IN CHINESE UNIVERSITIES
·
2014
·Vol. 30
·期 5
·731-737
·
IF 1.119
Ma Jingwei,Kan Hong,Ma Yinghui,Men Lihui,Pi Zifeng,Liu Zhiqiang,Liu Zhongying
Ultra performance liquid chromatographic-electrospray ionization-mass spectrometry(UPLC-ESI-MS) was used to investigate the potential interaction between selected ingredients of Aconitum and fritillary. The efflux ratios of 14-benzoylmesaconine(BM), 14-benzoylaconine(BC), 14-benzoylhypaconine(BH), mesaconitine(MA), aconitine( AC) and hypaconitine(HA) was 11.16, 12.53, 11.69, 12.8, 11.03 and 6.15, respectively, and the secretion of them was inhibited by Verapamil, which means they are the substrates of permeability-glycoprotein(P-gp). The transport of Aconitum alkaloids extract through a Caco-2 cell monolayer was determined in the absence and presence of fritillary extract. And the fritillary extract increased the absorption of Aconitum alkaloids. Peimine(PE) and peiminine( PEN) in fritillary increased the absorption of pure Aconitum alkaloids. The transport of digoxin was respectively enhanced by PE and PEN, which means they are the inhibitors of P-gp. PEN showed more effective inhibition than PE at the same concentration. The in vitro data suggest that the compounds such as fritillary present in alkaloids were able to inhibit the P-gp activity and lead modifying the transport of alkaloids.
研究领域:
药理学
·
中药学
·
生物化学
✓ 已验证
产品关联
DOI
高影响因子
JOURNAL OF CHEMICAL SCIENCES
·
2024
·Vol. 136
·期 1
·1-9
·
IF 1.7
Zhang Mingyu,Yan Dong,Xu Rui,Tang Yuqi,Xu Shuangping,Qu Yanqing,Xu Jingyu,Du Boyu,Jia Hongge
A new rhodium complex [Rh(cod)(TTT) 2 ] was synthesized by [Rh(cod)Cl] 2 as a precursor, and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TTT) as a ligand. Its structure was verified by 1 H and 13 C NMR. The results indicate that the complex shows high activity in phenylacetylene polymerization. It was applied to the polymerization of phenylacetylene with a yield of 45.0% and Mw = 2.26×10 5 at ultra-low rhodium feed ratio ([Rh.]/[M.]=1/60000). Graphical abstract A new rhodium complex [Rh(cod)(TTT) 2 ] was synthesized by [Rh(cod)Cl] 2 as a precursor, and 4,4',4''-(1,3,5-triazine-2,4,6-triyl)trianiline (TTT) as a ligand. It was applied to the polymerization of phenylacetylene with a yield of 45.0% and Mw = 2.26×10 5 at ultra-low rhodium feed ratio ([Rh.]/[M.]=1/60000
研究领域:
无机化学
·
有机金属化学
·
高分子化学
·
催化
✓ 已验证
DOI
高影响因子
CATALYSIS LETTERS
·
2023
·Vol. 154
·期 2
·524-531
·
IF 2.8
Liu Yunyi,Zhao Dongmei,Tang Wanjun,Li Tingcheng,You Qingliang,Xie Guangyong
Vanadium-chromium composite oxides have held much interest due to their distinctive catalytic properties, which depend on their morphology and crystal structure. During the hydrothermal synthesis, reducing agents play an important role in controlling the morphology and the crystal structure of vanadium-chromium oxides. In this work, nanocrystalline chromium vanadate (CrVO 4 ) were prepared by a simple one-pot hydrothermal method based on the reaction between V 2 O 5 and CrO 3 . Three different CrVO 4 crystal structures, including orthorhombic CrVO 4 , monoclinic CrVO 4 , and mixed-phased-CrVO 4 were obtained by using different reducing agents. X-ray diffraction (XRD), scanning electron microscopy (SEM) and transmission electron microscopy (TEM) studies revealed that nanocrystalline monoclinic CrVO 4 was obtained using tartaric acid as the reducing agent. Catalytic properties of nanostructured CrVO 4 were investigated for the vapor phase ammoxidation of 2-chlorotoluene to 2-chlorobenzonitrile. The monoclinic CrVO 4 nanostructures exhibited excellent catalytic performance due to the proper distribution of V-O-Cr bond. It was one of the most efficient binary catalysts for such vapor phase ammoxidation processes to the best of our knowledge, and may have great potential for the ammoxidation of halogen-substituted toluenes. Graphical Monoclinic CrVO 4 nanostructures are controllably prepared by hydrothermal process using tartaric acid as reductant and exhibit excellent catalytic performance for ammoxidation of 2-chlorotoluene.
研究领域:
材料科学
·
纳米技术
·
催化
·
无机化学
·
化学合成
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）