CHEMICAL COMMUNICATIONS
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2011
·Vol. 48
·期 14
·2024-2026
·
IF 5.787
Jian Gao,Qing-Wen Song,Liang-Nian He,Zhen-Zhen Yang,Xiao-Yong Dou
An iron(III)-catalyzed three-component coupling reaction of alkynes, CH2Cl2 and amines was developed for facile synthesis of propargylamines. Preliminary mechanism investigation using in situFT-IR reveals that the crucial Fe-acetylide intermediate could be formed through C–H bond activation of alkynes thanks to cooperative effect of FeCl3 and 1,1,3,3-tetramethylguanidine.
研究领域:
有机化学
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催化化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
APPLIED CATALYSIS A-GENERAL
·
2021
·
IF 5.706
Wei Sun,Shijie Shao,Jun Pan,Yangyang Wang,Hangqi Xia,Xiaohui Gao,Hao Zhang,Qiguang Dai,Li Wang,Xingyi Wang
Ce-Ti-Zr mixed oxide catalysts prepared by sol-gel method were used in catalytic combustion of CH 2 Cl 2 . The characterization reveals that the incorporation of Ce and Zr into TiO 2 anatase or Ti and Zr into CeO 2 fluorite promotes hydroxyl groups, Lewis acidity and surface oxygen through the formation of Ti-O-Zr, Ti-O-Ce and Ce-O-Zr species. Ce-Ti-Zr catalysts show high activity for CH 2 Cl 2 oxidation with the rate of 5.66 × 10 −3 –6.45 × 10 −3 μmol s −1 m −2 at 250 °C and high stability for 50 h. The substitution of surface oxygen for Cl maintains the availability of Ti-OH and thus promotes Cl removal as HCl, which is verified by a great increase in the stable activity of physically closely contacted mixture of separated CeO 2 and TiO 2 or Ti 9 Zr 1 particles. In situ FT-IR shows that CH 2 Cl 2 interacts with Ti-OH to form -O-CH 2 -O-, which is quickly rearranged into formate. Finally, formate is oxidized with surface oxygen into CO or CO 2 .
研究领域:
催化
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环境科学
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材料科学
✓ 已验证
产品关联
DOI
高影响因子
ANALYTICAL CHEMISTRY
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2019
·
IF 6.35
Jingyun Huang,Bo Yang,Jinian Shu,Zuojian Zhang,Zhen Li,Kui Jiang
Excited-state CH2Cl2-induced associative ionization (AI) is a newly developed ionization method that is very effective for oxygenated organics. However, this method is not widely known. In this study, an unprecedented ionization efficiency and ultrafast reaction rate of AI toward nitro compounds were observed. The ionization efficiencies of o-nitrotoluene (o-NT), m-nitrotoluene (m-NT), and nitrobenzene (NB) were as high as (28 ± 3)%, (27 ± 2)%, and (13 ± 1)%, respectively (∼1–3 ions for every 10 molecules). The measured reaction rate coefficients of these nitroaromatics were (0.5–1.3) × 10–7 molecule–1 cm3 s–1 (∼300 K). These unusual rate coefficients indicated strong long-range interactions between the two neutral reactants, which was regarded as a key factor leading to the ultrahigh ionization efficiency. The detection sensitivities of the nitroaromatics, (1.01–2.16) × 104 counts pptv–1 in 10 s acquisition time, were obtained by an AI time-of-flight mass spectrometer (AI-TOFMS). These experimental results not only provide new insight into the AI reaction but also reveal an excellent ionization method that can improve the detection sensitivity of nitroaromatics to an unprecedented degree.
研究领域:
化学
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分析化学
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物理化学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
RSC Advances
·
2014
·Vol. 4
·期 49
·25933-25939
·
IF 3.708
Qingfeng Liu,Yansen Zhang,Zhiguo Zhang,Tongxin Liu,Lei Shi,Guisheng Zhang
This paper describes a highly efficient and facile transformation of substituted oxazolidin-2-ones to methylene-bridged 3,3′-bis(oxazolidin-2-one) derivatives in a mixture solvent of CH2Cl2 (DCM) and N,N-dimethylformamide (DMF) in the presence of NaH at ambient temperature. Isotopic labeling experiments indicated that the C of the bridged methylene group was derived from CH2Cl2 instead of DMF and other unknown substances in the NaH reagent (60% dispersion in mineral oil).
研究领域:
有机化学
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药物化学
✓ 已验证
产品关联
DOI
高影响因子
Catalysts
·
2024
·Vol. 14
·期 12
·886
·
IF 3.8
Zhiyong Fang,Xiangyu Song
In the study presented herein, a series of TiO2-supported Ru catalysts were prepared through over-impregnation with different amounts of H2O2and applied to the catalytic combustion of dichloromethane (DCM). The experimental results show that the optimal (1 H2O2)-Ru@TiO2catalyst sample yields 90% DCM conversion at 301 °C, which is 40 °C lower than the temperature required by the (0 H2O2)-Ru@TiO2catalyst. This good activity is related to its high number of acid sites (especially Brønsted acid sites), an appropriate amount of uniformly dispersed RuO2particles, and strong interaction between RuO2and the TiO2support. In addition, excessive H2O2leads to the growth and phase segregation of RuO2, which weakens the interaction between RuO2and the TiO2support and decreases catalytic activity. Moreover, H2O2addition also contributes to the stability of catalysts, which possibly results from the re-dispersion of RuO2on the TiO2support during the reaction.
研究领域:
环境科学
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催化化学
✓ 已验证
产品关联
DOI
高影响因子
THIN SOLID FILMS
·
2014
·
IF 1.867
Zhongshi Xu,Qi Kang,Tingting Cai,Tingting Huang,Ping Zhang,Dazhong Shen
In this work, the adsorption kinetics of 1,2-dichloroethane (DCE) on [Cu(C 24 H 22 N 4 O 3 )]·CH 2 Cl 2 metal-organic framework (Cu-MOF) film were monitored in real time by a quartz crystal microbalance technique. It is shown that the adsorption process follows closely the pseudo-second-order kinetic model. With increasing amount of DCE added, the adsorption rate constant decreases while the initial adsorption rate increases. More than half of DCE adsorbed on Cu-MOF film is reversible with respect to the concentration dilution in gas phase. The adsorption isotherms are fitted well by the Langmuir model. The pre-adsorbed N 2 at atmospheric pressure on Cu-MOF film reduces slightly the adsorption rate constant, equilibrium constant and capacity of DCE. The adsorption rates at vapor pressure of DCE are 1.2–1.8 times of those in the presence of N 2 at atmospheric pressure. With increasing film thickness, the adsorption rate constant and mass adsorbed per unit film mass decreased. For DCE adsorbed at its vapor pressure (25 °C) on Cu-MOF film with thickness of 0.251, 0.589 and 1.19 μm, the adsorption equilibrium constants are 716.5, 695.5 and 649.2 L/mol, and the saturation adsorption capacities are 6.537, 5.742 and 5.193 mmol/g, respectively. With increasing temperature, the adsorption rate constant increases, but the mass of DCE adsorbed on the adsorption equilibrium constant and capacity decreases.
研究领域:
材料科学
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化学工程
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物理化学
✓ 已验证
产品关联
DOI
高影响因子
ANALYST
·
2019
·Vol. 144
·期 16
·4897-4907
·
IF 4.019
Rui-Qian Zhang,Zhan-Qing Liu,Yan-Ling Luo,Feng Xu,Ya-Shao Chen
Novel nanocomposites consisting of polystyrene-block-polybutadienyl polyhexamethylene dicarbamate-block-polystyrene (PS-b-HTPB5-b-PS) and multiwalled carbon nanotubes (MWCNTs) were designed and prepared via noncovalent interactions. Scanning electron microscopy and transmission electron microscopy observations showed that segregated networks of MWCNTs were formed due to the cladding of PS-b-HTPB5-b-PS, presenting a parallel-arranged topology of the MWCNTs in a continuous PS-b-HTPB5-b-PS phase, which improved the dispersibility of the MWCNTs. The nanocomposites were fabricated into vapor sensing elements to detect CH2Cl2 vapor in the environment, exhibiting excellent responsive sensitivity, reproducibility and a low limit of detection (LOD) of 1 ppm when exposed to CH2Cl2 vapor. The chain extension of HTPB overcame the fragility and improved the tenacity of the thin films, and the responsivity was optimized by adjusting the content of the MWCNTs and the length of the PS chains. The newly developed conductive composites can be applied as a promising vapor sensor to accurately monitor CH2Cl2 vapor in the environment.
研究领域:
材料科学
·
传感器技术
✓ 已验证
产品关联
DOI
PubMed
高影响因子
INDUSTRIAL & ENGINEERING CHEMISTRY RESEARCH
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2020
·
IF 3.573
Lirong Lv,Sheng Wang,Ya Ding,Lei Zhang,Yang Gao,Shudong Wang
In this study, the divergent behaviors were elucidated for CH2Cl2 and CH3Br oxidation over TiO2 and Ru/TiO2. Possible reaction mechanisms were elucidated. It was concluded that the adsorption and activation of halogenated volatile organic compounds were strongly dependent on the hard–soft acid–base theory.
研究领域:
化学
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催化反应
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环境科学
✓ 已验证
产品关联
DOI
高影响因子
WATER RESEARCH
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2024
·
IF 11.4
Yurong Wu,Guangliang Liu,Xiaoquan Liu,Yuxiang Mao,Yingying Guo,Yanwei Liu,Liuchao Zhu,Yongguang Yin,Yong Cai,Guibin Jiang
Ethylmercury (EtHg), similar to methylmercury (MeHg), is highly neurotoxic and bioaccumulative. Although recent studies suggested its occurrence in natural soils and sediments, the common propylation derivatization for EtHg analysis might generate EtHg artifacts, potentially leading to its overestimation in environmental samples. Furthermore, the extensive environmental prevalence of EtHg remains unverified, keeping its importance largely uncertain. This study investigated the formation of EtHg artifacts during propylation derivatization, evaluating artifacts formation and recoveries under different extraction methods with real samples, and confirmed the widespread occurrence of EtHg in Chinese wetlands. EtHg artifacts were obviously present during the propylation derivatization and strongly dependent on the levels of Hg 2+ (0.1–10 ng) in the derivatization solution (R² = 0.99), accounting for 1.38–2.14% of Hg 2+ . CuSO 4 -HNO 3 CH 2 Cl 2 extraction (effectively removing Hg 2+ ) combined with propylation derivatization offers excellent recovery (81–86%) and low artifacts (< LOD: 1.98 × 10 −4 ng/g) for EtHg measurement in soils/sediments, with results aligning with those from online solid phase extraction-high performance liquid chromatography-inductively coupled plasma mass spectrometry (R 2 = 0.99). Additionally, we observed the occurrence of EtHg in soil and sediment samples across 14 Chinese wetlands, with concentrations varying from 6.08 to 171 pg/g, similar to MeHg concentrations at some sites. EtHg positively correlates with MeHg, total Hg, and total organic carbon across all samples, indicating a possible biological formation. These findings help better understand and predict the prevalence of EtHg in wetlands and its key role in environmental Hg cycle.
研究领域:
环境科学
·
分析化学
·
生态毒理学
✓ 已验证
产品关联
DOI
PubMed
高影响因子
Surface Topography-Metrology and Properties
·
2020
·Vol. 8
·期 4
·045009
·
IF 1.613
Bo Lin,Wen-Xu He,Li-Wang Jiang,Zeng-Tian Li,Hua-Ying Wang,Ying-Xuan Wu,Fu-An He,Hui-Jun Wu
The hierarchically-micro/nanoscale rough surface structure and the high surface hydrophilicity are two necessary factors to construct the superhydrophilic-underwater superoleophobic materials for oil-water separation. In this work, an effective method on the fabrication of the superhydrophilic-underwater superoleophobic sponges was developed, in which the mixture of the Fe3O4 nanoparticles or (and) the SiO2 nanoparticles, the chitosan, the polyvinyl alcohol, and the glutaraldehyde was coated on the polymeric sponge by dip-coating to obtain the surface-modified sponges possessing the rough superhydrophilic-underwater superoleophobic surface. The structure of the surface-modified sponges were investigated by TGA, FTIR, WAXD, XPS, SEM, two-dimensional EDS element mapping as well as VSM, and the underwater superoleophobicity of the surface-modified sponges was proved by CH2Cl2 contact angle measurement. Furthermore, the resultant surface-modified sponges exhibited good oil-water separation ability by adsorption and filtration.
研究领域:
材料科学
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化学工程
·
环境科学
✓ 已验证
DOI
高影响因子
危险品化学品经营许可证（带存储）