Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H+ and the route of reaction initi...Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H+ and the route of reaction initiated the alkylation of benzene with ethylene catalyzed by [bmim]Cl/FeCl3 ionic liquid. The fact that dewatered ionic liquids have catalytic activity for the alkylation of benzene with ethylene suggests that there exists a new catalytic route. The distinctly Bronsted acid properties of 2-H in [bmim]Cl were found through FT-IR and HNMR analysis of [bmim]Cl after titration with water free KOH in alcohol solution. In addition, the chemical shifts of proton on the [bmim]Cl ring, especially 2-H, are sensitive to the change of FeCl3 content and shifted downfield when FeCl3 was added into [bmim]Cl to form ionic liquid. Thus 2-H was easy to be disengaged from imidazolium ring with formation of H+ to initiate the reaction. The isotope-substituted method was employed to prove this mechanism, through the GC-MS analysis of alkylation products of deuterated benzene with ethylene. The route of alkylation catalyzed by FeCl3 ionic liquid was found to follow the carbocation mechanism, the resource of H+ was presented and proved using HNMR analysis of ionic liquid to inspect the intensity change of 2-H. It was found that the intensity of 2-H reduced 23% after reaction showing that the H+ arising from alkylation reaction was supplied by 2-H on the imidazole ring.展开更多
Reaction of alkanones with 1-butyl-3-methylimidazolium tribromide （[Bmim]Br3） under solvent-free conditions, selectively gave the corresponding ct-bromoalkanones with excellent yields.
Reaction of activated aromatics containing phenobs, naphthol, methoxynaphthalenes,anisole etc. with 1-butyl-3-methylimidazolium tribromide （[Bmim]Br3） under solvent-free conditions, selectively gave the correspondin...Reaction of activated aromatics containing phenobs, naphthol, methoxynaphthalenes,anisole etc. with 1-butyl-3-methylimidazolium tribromide （[Bmim]Br3） under solvent-free conditions, selectively gave the corresponding monobromination products with excellent yields.展开更多
bmim]Cl/FeCl3 ionic liquids (where bmim = 1-butyl-3-methylimidazolium) were characterized by XPS (X-ray photoelectron spectroscopy), FT-IR (Fourier transform infrared spectroscopy), Raman and NMR (nuclear magnetic r...bmim]Cl/FeCl3 ionic liquids (where bmim = 1-butyl-3-methylimidazolium) were characterized by XPS (X-ray photoelectron spectroscopy), FT-IR (Fourier transform infrared spectroscopy), Raman and NMR (nuclear magnetic resonance) spectra. The results show that Fe2Cl7 and FeCl4 ions are the principal anions in acidic ionic liquids, - - whose concentrations change with the content of FeCl3 and an equilibrium exists between them. An isosbestic point existing in FT-IR spectra indicates that an interaction involving at least two species occurs and their concentrations vary with acidity. Chemical shifts of the hydrogen located in the cations of ionic liquids are sensitive to the composition of ionic liquids. The change in chemical shifts may be explained in terms of anion-cation interactions. The chemical shifts of 2-H are affected by metal halides, which shift downfield and the 2-H is more deshielded with the increase in metal halides.展开更多
Photocatalytic oxidative desulfurization of gasoline in[BMIm]Cu_2Cl_3 ionic liquid was studied.A500-W high-pressure mercury lamp was used as the light source for irradiation,nano-TiO2 was used as thephotocatalyst and ...Photocatalytic oxidative desulfurization of gasoline in[BMIm]Cu_2Cl_3 ionic liquid was studied.A500-W high-pressure mercury lamp was used as the light source for irradiation,nano-TiO2 was used as thephotocatalyst and air was introduced by a gas pump to supply O_2 as the oxidant.Influence of the ratio ofV(ionic liquid) to V(oil) and the TiO_2 addition on the desulfurization rate of gasoline was investigated.Anoxidative kinetics equation was founded.The results showed that the [BMIm]Cu2CIs ionic liquid was aneffective extractant for the desulfurization of gasoline.The appropriate TiO_2 addition was 0.05 g in 50 mLof reaction mixture.The yield of desulfurized gasoline could reach 98.2% after being subjected to reactionfor 2 h under the conditions of adopting a ratio of V(ionic liquid):V(oil)=1:4,an air flow of 100 mL/min anda TiO_2 addition dosage of 0.05 g.The kinetics reaction for photo-oxidation of gasoline was a first-orderreaction with an apparent rate constant of 1.9664 h^(-1)and a half-time of 0.3525 h.展开更多
文摘Up to now the mechanism of Friedel-Crafts reactions catalyzed by ionic liquid have not been fully understood, while carbocation mechanism was assumed. It was found that the source of H+ and the route of reaction initiated the alkylation of benzene with ethylene catalyzed by [bmim]Cl/FeCl3 ionic liquid. The fact that dewatered ionic liquids have catalytic activity for the alkylation of benzene with ethylene suggests that there exists a new catalytic route. The distinctly Bronsted acid properties of 2-H in [bmim]Cl were found through FT-IR and HNMR analysis of [bmim]Cl after titration with water free KOH in alcohol solution. In addition, the chemical shifts of proton on the [bmim]Cl ring, especially 2-H, are sensitive to the change of FeCl3 content and shifted downfield when FeCl3 was added into [bmim]Cl to form ionic liquid. Thus 2-H was easy to be disengaged from imidazolium ring with formation of H+ to initiate the reaction. The isotope-substituted method was employed to prove this mechanism, through the GC-MS analysis of alkylation products of deuterated benzene with ethylene. The route of alkylation catalyzed by FeCl3 ionic liquid was found to follow the carbocation mechanism, the resource of H+ was presented and proved using HNMR analysis of ionic liquid to inspect the intensity change of 2-H. It was found that the intensity of 2-H reduced 23% after reaction showing that the H+ arising from alkylation reaction was supplied by 2-H on the imidazole ring.
文摘Reaction of alkanones with 1-butyl-3-methylimidazolium tribromide （[Bmim]Br3） under solvent-free conditions, selectively gave the corresponding ct-bromoalkanones with excellent yields.
文摘Reaction of activated aromatics containing phenobs, naphthol, methoxynaphthalenes,anisole etc. with 1-butyl-3-methylimidazolium tribromide （[Bmim]Br3） under solvent-free conditions, selectively gave the corresponding monobromination products with excellent yields.
文摘bmim]Cl/FeCl3 ionic liquids (where bmim = 1-butyl-3-methylimidazolium) were characterized by XPS (X-ray photoelectron spectroscopy), FT-IR (Fourier transform infrared spectroscopy), Raman and NMR (nuclear magnetic resonance) spectra. The results show that Fe2Cl7 and FeCl4 ions are the principal anions in acidic ionic liquids, - - whose concentrations change with the content of FeCl3 and an equilibrium exists between them. An isosbestic point existing in FT-IR spectra indicates that an interaction involving at least two species occurs and their concentrations vary with acidity. Chemical shifts of the hydrogen located in the cations of ionic liquids are sensitive to the composition of ionic liquids. The change in chemical shifts may be explained in terms of anion-cation interactions. The chemical shifts of 2-H are affected by metal halides, which shift downfield and the 2-H is more deshielded with the increase in metal halides.
基金the Research Foundation of Hebei Province Education Department(2007440)
文摘Photocatalytic oxidative desulfurization of gasoline in[BMIm]Cu_2Cl_3 ionic liquid was studied.A500-W high-pressure mercury lamp was used as the light source for irradiation,nano-TiO2 was used as thephotocatalyst and air was introduced by a gas pump to supply O_2 as the oxidant.Influence of the ratio ofV(ionic liquid) to V(oil) and the TiO_2 addition on the desulfurization rate of gasoline was investigated.Anoxidative kinetics equation was founded.The results showed that the [BMIm]Cu2CIs ionic liquid was aneffective extractant for the desulfurization of gasoline.The appropriate TiO_2 addition was 0.05 g in 50 mLof reaction mixture.The yield of desulfurized gasoline could reach 98.2% after being subjected to reactionfor 2 h under the conditions of adopting a ratio of V(ionic liquid):V(oil)=1:4,an air flow of 100 mL/min anda TiO_2 addition dosage of 0.05 g.The kinetics reaction for photo-oxidation of gasoline was a first-orderreaction with an apparent rate constant of 1.9664 h^(-1)and a half-time of 0.3525 h.
