通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选...通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选择性效应可以不同程度地活化Ti—O和Si—O键;19F MAS NMR证实了F-TS-1-M分子筛中氟元素是以Si-F和SiF62-的形式存在;29Si MAS NMR表明F-TS-1-M分子筛的骨架缺陷位和表面羟基减少, Py-FT-IR结果表明F-TS-1-M的Lewis酸性和疏水性高于F-TS-1-T、 TS-1-M和TS-1.在环己酮氨肟化的反应中表现出优异的催化性能.展开更多
In our synthetic studies toward huperzine A, a diastereoselective α′-alkylation of the α-amido-γ-methyl hexenone 4 was realized through a dianion intermediate which significantly enhanced the reactivity. Under the...In our synthetic studies toward huperzine A, a diastereoselective α′-alkylation of the α-amido-γ-methyl hexenone 4 was realized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular γ-arylation of 3 was observed, which generated 18 with bicyclo[3.3.1]nonane framework in satisfactory yield.展开更多
Phenylsulfonic acid functionalized mesoporous silica was synthesized by condensation of tetraethylorthosilicate with phenyltrimethoxysilane, and then sulfonation using 30% fuming sulfuric acid. The material was chara... Phenylsulfonic acid functionalized mesoporous silica was synthesized by condensation of tetraethylorthosilicate with phenyltrimethoxysilane, and then sulfonation using 30% fuming sulfuric acid. The material was characterized using FT-IR, DSC, XPS, TEM and N2 adsorption/desorption measurements. DSC revealed that sulfonic acid group of the catalyst was decomposed at 354.8℃, indicating that the catalyst exhibited high thermal stability. XPS showed that there existed three kinds of different silicon species on surface of the catalyst. The catalytic performance of the catalyst was evaluated using transetherification of alcohols with dimethoxymethane. It was found that among primary alcohols, the selectivities of the two long-chain alcohols for n-dedocanol and n-tetradecyl alcohol were higher than 97.0% at the conversions of 43.6% and 65.3%, respectively, while the selectivities of the short-chain alcohols except for n-hexanol were less than 90.0% at the conversions of over 80.0%. Due to steric bartier, the secondary alcohols such as /so-butanol and cyclohexanol afforded conversions of 79.4% and 60.5%, and the selectivities of the two alcohols were more than 90.0%. The sequence in conversion of the substituted phenols isas follows: p-nitrophenol>p-fluorophenol≥p-bromophenol>p-cresol>m-cresol.展开更多
CuMn mixed oxides catalysts doped with La were prepared following a co-precipitation method and used for the catalytic oxidation of toluene. Catalysts properties of the catalysts were investigated by X-ray diffraction...CuMn mixed oxides catalysts doped with La were prepared following a co-precipitation method and used for the catalytic oxidation of toluene. Catalysts properties of the catalysts were investigated by X-ray diffraction, N2 adsorption/desorption,scanning electron microscopy, H2-temperature-programmed reduction(H2-TPR), O2-temperature-programmed desorption(O2-TPD) and X-ray photoelectron spectroscopy techniques. Characterization data reveal that the phase change and decrease in crystallinity of the La-doped catalysts increase the number of oxygen vacancies. Improvements in reducibility and an increase in the amount of chemisorbed oxygen of the La-doped catalysts were also verified by H2-TPR and O2-TPD. The activity of the CuMn mixed oxides catalysts is significantly improved by the addition of a nominal amount of La. The CuMn/La-4 mol% catalyst exhibits the best catalytic activity, with a 90%conversion temperature of 255 ℃,attributed to a high Mn3+ratio, superficial chemisorbed oxygen,and high surface area. This study indicates La to be a promising dopant for Cu-Mn catalysts toward toluene oxidation.展开更多
基金The financial supports from the National Natural Science Foundation of China(Project NO.21403135)Shanxi provincial key research and development plan project(NO.201603D121018-1).
文摘通过微波辅助法制备了含氟的TS-1(F-TS-1-M),并与传统方法制备的氟改性TS-1(F-TS-1-T),微波处理的TS-1(TS-1-M)和未改性TS-1进行比较. XRD、 DR UV-Vis、 XPS表明F-TS-1-M和TS-1-M分子筛上的部分非骨架钛转变为骨架钛,这是由于微波的选择性效应可以不同程度地活化Ti—O和Si—O键;19F MAS NMR证实了F-TS-1-M分子筛中氟元素是以Si-F和SiF62-的形式存在;29Si MAS NMR表明F-TS-1-M分子筛的骨架缺陷位和表面羟基减少, Py-FT-IR结果表明F-TS-1-M的Lewis酸性和疏水性高于F-TS-1-T、 TS-1-M和TS-1.在环己酮氨肟化的反应中表现出优异的催化性能.
基金supported by the National Natural Science Foundation of China (20902101 & 21172246)
National Basic Research Program of China (973 Program) (2010CB833206)
文摘In our synthetic studies toward huperzine A, a diastereoselective α′-alkylation of the α-amido-γ-methyl hexenone 4 was realized through a dianion intermediate which significantly enhanced the reactivity. Under the attempted Heck reaction conditions, an unexpected and unprecedented palladium-catalyzed intramolecular γ-arylation of 3 was observed, which generated 18 with bicyclo[3.3.1]nonane framework in satisfactory yield.
文摘 Phenylsulfonic acid functionalized mesoporous silica was synthesized by condensation of tetraethylorthosilicate with phenyltrimethoxysilane, and then sulfonation using 30% fuming sulfuric acid. The material was characterized using FT-IR, DSC, XPS, TEM and N2 adsorption/desorption measurements. DSC revealed that sulfonic acid group of the catalyst was decomposed at 354.8℃, indicating that the catalyst exhibited high thermal stability. XPS showed that there existed three kinds of different silicon species on surface of the catalyst. The catalytic performance of the catalyst was evaluated using transetherification of alcohols with dimethoxymethane. It was found that among primary alcohols, the selectivities of the two long-chain alcohols for n-dedocanol and n-tetradecyl alcohol were higher than 97.0% at the conversions of 43.6% and 65.3%, respectively, while the selectivities of the short-chain alcohols except for n-hexanol were less than 90.0% at the conversions of over 80.0%. Due to steric bartier, the secondary alcohols such as /so-butanol and cyclohexanol afforded conversions of 79.4% and 60.5%, and the selectivities of the two alcohols were more than 90.0%. The sequence in conversion of the substituted phenols isas follows: p-nitrophenol>p-fluorophenol≥p-bromophenol>p-cresol>m-cresol.
基金supported by the National Natural Science Foundation of China(91645203,21773253)China Postdoctoral Science Foundation(2017M611002)+1 种基金Beijing Natural Science Foundation,China(2182092)Youth Innovation Promotion Association,Chinese Academy of Sciences(2018041).
基金Sichuan Provincial Science and Technology Agency(2018GZ0414)the Chengdu Science and Technology Bureau Huimin Projects(2016-HM01-00075-SF).
文摘CuMn mixed oxides catalysts doped with La were prepared following a co-precipitation method and used for the catalytic oxidation of toluene. Catalysts properties of the catalysts were investigated by X-ray diffraction, N2 adsorption/desorption,scanning electron microscopy, H2-temperature-programmed reduction(H2-TPR), O2-temperature-programmed desorption(O2-TPD) and X-ray photoelectron spectroscopy techniques. Characterization data reveal that the phase change and decrease in crystallinity of the La-doped catalysts increase the number of oxygen vacancies. Improvements in reducibility and an increase in the amount of chemisorbed oxygen of the La-doped catalysts were also verified by H2-TPR and O2-TPD. The activity of the CuMn mixed oxides catalysts is significantly improved by the addition of a nominal amount of La. The CuMn/La-4 mol% catalyst exhibits the best catalytic activity, with a 90%conversion temperature of 255 ℃,attributed to a high Mn3+ratio, superficial chemisorbed oxygen,and high surface area. This study indicates La to be a promising dopant for Cu-Mn catalysts toward toluene oxidation.