A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic syn...A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic synthesis of cyclic carbonates and oxazolidinones via the cycloaddition reactions between CO_(2) and epoxides or aziridines with excellent yield and high selectivity in the absence of co-catalyst,metal and solvent.Due to the synergistic effects of hydroxyl groups and halogen anion,the cycloaddition reactions proceeded smoothly either at atmospheric pressure or room temperature.The selectivity for substituted oxazolidinones at 5-and 4-positions can be tuned via changing the reaction conditions.Finally,possible mechanisms including the activation of both CO_(2) and epoxide or aziridines were proposed based on the literatures and experimental results.展开更多
The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocataly...The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocatalytic activity of ABO 3 increases with increasing atomic number of atom B(Ti—Co) when A site atom keeps constant. It is connected with the rise of Allred Rochow electronegativity of atom B, the decrease of ABO 3 energy gap(energy defference between the filled p bands of O 2- and the unoccupied 3 d band of neighboring atom B) and the increase of the third atomic ionizaton potentials of atom B. It has been also proved that the photocatalytic activity of ABO 3 compounds increases with increasing χ AR of atom A(Ca, Cd, Pb).展开更多
The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface...The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface dispersed ceria species and crystalline CeO\-2 shows a significant enhancement on the activity. The effect of ceria species is contributed to their promoting the reduction of copper oxide species.展开更多
文摘A series of multi-hydroxyl bis-(quaternary ammonium)ionic liquids(Ils1‒7)was prepared as bifunctional catalysts for the chemical fixation of CO_(2).All these ionic liquid compounds were efficient for the catalytic synthesis of cyclic carbonates and oxazolidinones via the cycloaddition reactions between CO_(2) and epoxides or aziridines with excellent yield and high selectivity in the absence of co-catalyst,metal and solvent.Due to the synergistic effects of hydroxyl groups and halogen anion,the cycloaddition reactions proceeded smoothly either at atmospheric pressure or room temperature.The selectivity for substituted oxazolidinones at 5-and 4-positions can be tuned via changing the reaction conditions.Finally,possible mechanisms including the activation of both CO_(2) and epoxide or aziridines were proposed based on the literatures and experimental results.
文摘The perovskite(ABO 3) type oxides have a photocatalytic activity that can be characterized with decolorization of some organic dyes under irradiation of mercury lamp. The experimental results show that the photocatalytic activity of ABO 3 increases with increasing atomic number of atom B(Ti—Co) when A site atom keeps constant. It is connected with the rise of Allred Rochow electronegativity of atom B, the decrease of ABO 3 energy gap(energy defference between the filled p bands of O 2- and the unoccupied 3 d band of neighboring atom B) and the increase of the third atomic ionizaton potentials of atom B. It has been also proved that the photocatalytic activity of ABO 3 compounds increases with increasing χ AR of atom A(Ca, Cd, Pb).
文摘The catalytic activity measurement for the NO+CO reaction over CuO/CeO\-2/\%γ\%\|Al\-2O\-3 catalysts at a low\|temperature(200 ℃) shows that the activity is strongly related to ceria loading amount, and both surface dispersed ceria species and crystalline CeO\-2 shows a significant enhancement on the activity. The effect of ceria species is contributed to their promoting the reduction of copper oxide species.
