A novel CF_3-containing building block, (Z)-ethyl 3-bromo-4,4,4-trifluoro-2-butenoate, was easily prepared from CF_3CBr_3, the former reacted with alkynes Or organozinc reagents in the presence of Pd complexes to affo...A novel CF_3-containing building block, (Z)-ethyl 3-bromo-4,4,4-trifluoro-2-butenoate, was easily prepared from CF_3CBr_3, the former reacted with alkynes Or organozinc reagents in the presence of Pd complexes to afford useful CF_3-containing intermediates in good yield.展开更多
α-(Trifluoromethyl)styrene and its derivatives have found wide applications in the fields of pharmaceuti-cals,agrochemicals,and advanced materials.They are also versatile trifluoromethyl-containing building blocks fo...α-(Trifluoromethyl)styrene and its derivatives have found wide applications in the fields of pharmaceuti-cals,agrochemicals,and advanced materials.They are also versatile trifluoromethyl-containing building blocks for the preparation of various trifluoromethyl-containing,fluorine-containing or nonfluorinated compounds.Recently,great efforts have been made to develop diverse reactions for rapidly accessing a wide range of valuable gem–difluoroalkenes and gem–difluoroalkylated compounds via defluorinative re-action or the defluorinative ipso-functionalization reaction ofα-(trifluoromethyl)styrenes,respectively.In contrast,α-(trifluoromethyl)styrenes remain notably underdeveloped with respect to their use in cycload-dition and hydroaddition reaction with retaining of three C–F bonds.This short review herein is aimed to summarize the recent progress on the cycloaddition and hydroaddition reaction including nucleophilic,radical and transition metal-catalyzed addition ofα-(trifluoromethyl)styrenes without accompanying de-fluorination.展开更多
Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The co...The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows： the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.展开更多
The rheological behavior of Cr_(2)_(3)-containing slags was investigated using a rotating cylinder viscometer and the solid fraction and phases of Cr_(2)_(3)in molten slags were also calculated and observed at differe...The rheological behavior of Cr_(2)_(3)-containing slags was investigated using a rotating cylinder viscometer and the solid fraction and phases of Cr_(2)_(3)in molten slags were also calculated and observed at different temperatures.Furthermore,the viscosities of CaO–SiO2–Cr_(2)_(3)(–10%Al2O3)slags were measured from 1703 to 1953 K and the influence of Cr_(2)_(3)content on the viscosity and rheological behavior of molten slags was investigated.The calculation revealed that the solid fraction of the molten slags varied with the Cr_(2)_(3)content and maximum temperature,and the fluid properties transitioned from Newtonian to non-Newtonian behavior when the solid fraction reached 5%.Moreover,the increase in Cr_(2)_(3)content led to an increase in the viscosity as the slags displayed Newtonian flow characteristics and a decrease in the viscosity when slags exhibited non-Newtonian flow characteristics.The viscosity results of Cr_(2)_(3)-containing slag from 1703 to 1953 K and from 1703 to 1813 K were also discussed with the morphologies.展开更多
By using a two-stage soapless emulsion polymerization, four kinds of core-shell nanoparticles have been prepared,which are composed of a polystyrene core having an average diameter of 256 nm and a poly(methyl methacry...By using a two-stage soapless emulsion polymerization, four kinds of core-shell nanoparticles have been prepared,which are composed of a polystyrene core having an average diameter of 256 nm and a poly(methyl methacrylate-co-acrylicacid) shell. The transmission electron microscopy (TEM) micrographs and the atomic force microscopy (AFM) imagesevidenced the presence of a core-shell structure. In the infrared spectra, the shift of v_(COOH) to lower wavenumber withincreasing Eu^(3+) ion content indicates that coordination between the oxygen of the carboxylic group and Eu^(3+) has occurred.The fluorescence intensity of ~5D_0-~7F_2 transition was observed to reach its maximum with a carboxyl group molar percentageof 40% in the shell and an Eu^(3+)/--COO^- molar ratio of 1:3. The fluorescence intensity ratio of ~5D_0-~7F_2 to ~5D_0-~7F_1 transition reached its maximum with an Eu^(3+)/--COO^- molar ratio of 1:3 for all the four series.展开更多
为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基...为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基组(augmented correlation-consistent polarized valence triple-zeta, Aug-cc-pVTZ)对该复合物的5种结构(S1′、S2、S3、S4、A)进行几何优化、频率计算;然后,引入键函数(3s3p2d1f),在包含单激发、双激发和微扰三激发的耦合簇(coupled cluster with single, double, and perturbative triple excitations, CCSD(T))方法结合Aug-cc-pVTZ的水平上计算稳定结构的分子间相互作用能,并对最稳定结构的单体谱带基线平移进行预测。结果表明,S1′为该复合物的最稳定结构,其分子间相互作用能为-3.81 kJ/mol,其能量分解中交换能占比最高为38%。此外,研究中发现了复合物的2个新的稳定结构S4、A,其分子间相互作用能分别为-2.68、-2.72 kJ/mol。单体谱带基线平移预测表明,在S1′结构中,相比于自由单体振动,复合物中CF3Cl单体的C-Cl键伸缩振动发生了红移,而CO的伸缩振动则表现为蓝移,这表明分子间卤键对分子内动力学存在显著影响。该研究结果为进一步实验测量CF3Cl-CO复合物光谱提供了理论参考。展开更多
A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a resi...A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a residual melt with a FeO concentration of 75−88 wt.%and produce Ca_(2)SiO_(4).In-situ observations suggested that the reaction was impeded in some way.Quenching experiments revealed that the initial reaction products consisted of calcium ferrite compounds and FeO−CaO melt.At the FeO−CaO melt/AFMT interface,Ca_(2)SiO_(4) particles precipitated,forming a dense Ca_(2)SiO_(4) film that significantly impeded mass transfer.Although trace amounts of Al_(2)O_(3) in AFMT temporarily enhanced mass transfer,they were insufficient to overcome this retardation effect.The decomposition reaction was far from achieving equilibrium,demonstrating a self-retardation effect.Measures must be implemented to eliminate this self-retardation effect and enhance the efficiency of reaction kinetics.展开更多
基金This work was partially supported by the National Natural Science Foundation of China.
文摘A novel CF_3-containing building block, (Z)-ethyl 3-bromo-4,4,4-trifluoro-2-butenoate, was easily prepared from CF_3CBr_3, the former reacted with alkynes Or organozinc reagents in the presence of Pd complexes to afford useful CF_3-containing intermediates in good yield.
基金support from the National Natural Science Foundation of China (No. 21472043)
文摘α-(Trifluoromethyl)styrene and its derivatives have found wide applications in the fields of pharmaceuti-cals,agrochemicals,and advanced materials.They are also versatile trifluoromethyl-containing building blocks for the preparation of various trifluoromethyl-containing,fluorine-containing or nonfluorinated compounds.Recently,great efforts have been made to develop diverse reactions for rapidly accessing a wide range of valuable gem–difluoroalkenes and gem–difluoroalkylated compounds via defluorinative re-action or the defluorinative ipso-functionalization reaction ofα-(trifluoromethyl)styrenes,respectively.In contrast,α-(trifluoromethyl)styrenes remain notably underdeveloped with respect to their use in cycload-dition and hydroaddition reaction with retaining of three C–F bonds.This short review herein is aimed to summarize the recent progress on the cycloaddition and hydroaddition reaction including nucleophilic,radical and transition metal-catalyzed addition ofα-(trifluoromethyl)styrenes without accompanying de-fluorination.
文摘Nitroalkanes react smoothly with CF_3CCl_2COCH=CHPh via Michael addition in the presence of inorganic bases such as KF/Al2O3 or K2CO3, giving fluorinecontaining γ-nitro ketones in good yields.
基金Item Sponsored by National Natural Science Foundation of China (50474037) Jiangsu Province Natural Science Foundation forUniversity of China (04BJK430022)
文摘The flux agents in common mould fluxes were fluoride and sodium oxide, which would do great harm to environments. B2O3 was selected as flux. The physical properties of B2O3-containing mould fluxes were studied. The corresponding physical properties of 37. 91% CAO-43.09% SiO2-5% Al2O3-5% MgO-2% Li20-7% B2O3 mould fluxes were as follows： the melting point was 909℃, the flowing temperature was 1 160℃, the viscosity and surface tension at 1300 ℃ were 0. 4 Pa · s and 0.32 N/m respectively, which could meet the demands for certain kinds of steels for mould fluxes in continuous casting.
基金the National Natural Science Foundation of China(No.U1960201)National Key R&D Program of China(No.2019YFC190570I)for their financial support of this research.
文摘The rheological behavior of Cr_(2)_(3)-containing slags was investigated using a rotating cylinder viscometer and the solid fraction and phases of Cr_(2)_(3)in molten slags were also calculated and observed at different temperatures.Furthermore,the viscosities of CaO–SiO2–Cr_(2)_(3)(–10%Al2O3)slags were measured from 1703 to 1953 K and the influence of Cr_(2)_(3)content on the viscosity and rheological behavior of molten slags was investigated.The calculation revealed that the solid fraction of the molten slags varied with the Cr_(2)_(3)content and maximum temperature,and the fluid properties transitioned from Newtonian to non-Newtonian behavior when the solid fraction reached 5%.Moreover,the increase in Cr_(2)_(3)content led to an increase in the viscosity as the slags displayed Newtonian flow characteristics and a decrease in the viscosity when slags exhibited non-Newtonian flow characteristics.The viscosity results of Cr_(2)_(3)-containing slag from 1703 to 1953 K and from 1703 to 1813 K were also discussed with the morphologies.
基金This work was supported by the Elite Foundation of Educational Department of Guangdong Province (No. 02047).
文摘By using a two-stage soapless emulsion polymerization, four kinds of core-shell nanoparticles have been prepared,which are composed of a polystyrene core having an average diameter of 256 nm and a poly(methyl methacrylate-co-acrylicacid) shell. The transmission electron microscopy (TEM) micrographs and the atomic force microscopy (AFM) imagesevidenced the presence of a core-shell structure. In the infrared spectra, the shift of v_(COOH) to lower wavenumber withincreasing Eu^(3+) ion content indicates that coordination between the oxygen of the carboxylic group and Eu^(3+) has occurred.The fluorescence intensity of ~5D_0-~7F_2 transition was observed to reach its maximum with a carboxyl group molar percentageof 40% in the shell and an Eu^(3+)/--COO^- molar ratio of 1:3. The fluorescence intensity ratio of ~5D_0-~7F_2 to ~5D_0-~7F_1 transition reached its maximum with an Eu^(3+)/--COO^- molar ratio of 1:3 for all the four series.
文摘为了探讨复合物中分子间相互作用对单体分子动力学的影响,对CF3Cl-CO复合物中单体振动谱带基线平移进行了预测。首先,采用二阶多体微扰理论(M?ller-Plesset perturbation theory of second order, MP2)结合扩展相关一致性极化价三重ζ基组(augmented correlation-consistent polarized valence triple-zeta, Aug-cc-pVTZ)对该复合物的5种结构(S1′、S2、S3、S4、A)进行几何优化、频率计算;然后,引入键函数(3s3p2d1f),在包含单激发、双激发和微扰三激发的耦合簇(coupled cluster with single, double, and perturbative triple excitations, CCSD(T))方法结合Aug-cc-pVTZ的水平上计算稳定结构的分子间相互作用能,并对最稳定结构的单体谱带基线平移进行预测。结果表明,S1′为该复合物的最稳定结构,其分子间相互作用能为-3.81 kJ/mol,其能量分解中交换能占比最高为38%。此外,研究中发现了复合物的2个新的稳定结构S4、A,其分子间相互作用能分别为-2.68、-2.72 kJ/mol。单体谱带基线平移预测表明,在S1′结构中,相比于自由单体振动,复合物中CF3Cl单体的C-Cl键伸缩振动发生了红移,而CO的伸缩振动则表现为蓝移,这表明分子间卤键对分子内动力学存在显著影响。该研究结果为进一步实验测量CF3Cl-CO复合物光谱提供了理论参考。
基金supported by the National Natural Science Foundation of China (No.52121004)the National Science Fund for Distinguished Young Scholars (No.51825403)+2 种基金the Science and Technology Innovation Program of Hunan Province,China (No.2021RC3013)National Key R&D Program of China (No.2022YFC3901602)the Major Science and Technology Project of Gansu Province,China (No.21ZD4GD033)。
文摘A method to upgrade the iron grade in copper slag was proposed using lime to decompose Al_(2)O_(3)-containing fayalite melt(AFMT).Thermodynamic calculations indicated that adjusting the CaO/AFMT ratio can yield a residual melt with a FeO concentration of 75−88 wt.%and produce Ca_(2)SiO_(4).In-situ observations suggested that the reaction was impeded in some way.Quenching experiments revealed that the initial reaction products consisted of calcium ferrite compounds and FeO−CaO melt.At the FeO−CaO melt/AFMT interface,Ca_(2)SiO_(4) particles precipitated,forming a dense Ca_(2)SiO_(4) film that significantly impeded mass transfer.Although trace amounts of Al_(2)O_(3) in AFMT temporarily enhanced mass transfer,they were insufficient to overcome this retardation effect.The decomposition reaction was far from achieving equilibrium,demonstrating a self-retardation effect.Measures must be implemented to eliminate this self-retardation effect and enhance the efficiency of reaction kinetics.
