Polystyrene-supported hydroquinone （PS-HQ） is presented as an in situ polymeric cocatalyst to replace polystyrenesupported benzoquinone （PS-BQ） in the PdCl2-catalyzed acetalization of methyl acrylate with methanol...Polystyrene-supported hydroquinone （PS-HQ） is presented as an in situ polymeric cocatalyst to replace polystyrenesupported benzoquinone （PS-BQ） in the PdCl2-catalyzed acetalization of methyl acrylate with methanol in supercritical carbon dioxide （scCO2） under oxygen atmosphere. Due to deletion of H2O2 oxidation step, PS-HQ is more convenient and relatively inexpensive.展开更多
The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine ...The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.展开更多
Several Pd--SnO2/ D3520 and Pd--PbO / D3520 catalysts with Pd/ D3J20, SnO2 / D3520 and PbO / D3520 catalysts as rference were studied by means of IR and XPS. Interaction between Pd and the second metal or between meta...Several Pd--SnO2/ D3520 and Pd--PbO / D3520 catalysts with Pd/ D3J20, SnO2 / D3520 and PbO / D3520 catalysts as rference were studied by means of IR and XPS. Interaction between Pd and the second metal or between metal and support was observed. Results show that there is a strong interaction between Pd and the second metal, but there is not an obvious interaction between metal and support. The active constituent is Pd￣0. Hydrogenation activity of the catalysts is altered because of the interaction between Pd and the second,metal.The activity of the catalysts for hydrogenation has relation to outer layer valence electron density of Pd.展开更多
The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the tempe...The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the temperature range from 25 to 40℃. The polymerization rate was measured by varying the concentrations of monomer, vanadyl polyimidodiacetate, thiourea and sulfuric acid. The overall rate of polymerization was summarized asRp=2.2×10~5e^(-6.560/RT) [AN]^(1.0)[PV]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)The molecular weight of polyacrylonitrile based on the experimental data was:(?)=k 1/T [pv]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)These results indicated that the chain radicals are terminated by combination and/or disproportionation rather than chain transfer. The cooperation effect of carboxylic groups and the macromolecular field effect of polymer supporter are the characters of vanadyl polyimidodiacetate such as the case reported in early paper.展开更多
In the course of investigating the catalytic behavior of metal complexes for ring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation and selective hydrogenation of olefins experimental res...In the course of investigating the catalytic behavior of metal complexes for ring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation and selective hydrogenation of olefins experimental results time and again indicate the presence of effects of macromolecular supports - the utilization of macromolecular supports increases obviously the activity, selectivity, and stability of the catalysts and so as to increase the conversion of substrates, yields of reactions, properties of formed polymers and so on. Discussed these effects on the basis of the authors' experiments. (Author abstract) 18 Refs.展开更多
文摘Polystyrene-supported hydroquinone （PS-HQ） is presented as an in situ polymeric cocatalyst to replace polystyrenesupported benzoquinone （PS-BQ） in the PdCl2-catalyzed acetalization of methyl acrylate with methanol in supercritical carbon dioxide （scCO2） under oxygen atmosphere. Due to deletion of H2O2 oxidation step, PS-HQ is more convenient and relatively inexpensive.
基金Project supported by State Education Committee Initial Research Crams for Return Scholar and supported by NSFC No 29774012.
文摘The optical alpha-amino acids were synthesized under room temperature by alkylation of N-(diphenyl methylene) glycine t-butyl ester under polymer-supported phase transfer conditions using polymer-supported cinchonine (or quinine) alkaloids as chiral phase transfer catalysts and dichloromethane as solvent, followed by hydrolysis of the above intermediates introduced to the final products-optical alpha-amino acids. This is a new method for the asymmetric synthesis of alpha-amino acids. The influences of catalyst, temperature, substrates, and organic solvents on the chemical yield and optical purities of products were studied.
文摘Several Pd--SnO2/ D3520 and Pd--PbO / D3520 catalysts with Pd/ D3J20, SnO2 / D3520 and PbO / D3520 catalysts as rference were studied by means of IR and XPS. Interaction between Pd and the second metal or between metal and support was observed. Results show that there is a strong interaction between Pd and the second metal, but there is not an obvious interaction between metal and support. The active constituent is Pd￣0. Hydrogenation activity of the catalysts is altered because of the interaction between Pd and the second,metal.The activity of the catalysts for hydrogenation has relation to outer layer valence electron density of Pd.
文摘The present paper deals with the kinetics of polymerization of acrylonitrile (AN) initialed by the redox system of polypropylene-based vanadyi polyimidodiacetate (PV)-thiourea (TU)in aqueous sulfuric acid in the temperature range from 25 to 40℃. The polymerization rate was measured by varying the concentrations of monomer, vanadyl polyimidodiacetate, thiourea and sulfuric acid. The overall rate of polymerization was summarized asRp=2.2×10~5e^(-6.560/RT) [AN]^(1.0)[PV]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)The molecular weight of polyacrylonitrile based on the experimental data was:(?)=k 1/T [pv]^(0.50)[TU]^(1.5)[H_2SO_4]^(2.0)These results indicated that the chain radicals are terminated by combination and/or disproportionation rather than chain transfer. The cooperation effect of carboxylic groups and the macromolecular field effect of polymer supporter are the characters of vanadyl polyimidodiacetate such as the case reported in early paper.
基金The project was supported by the National Natural Science Foundation of China, "Macromolecular ligand effects of catalytic system for ring opening metathesis polymerization of dicydopentadiene" (Approval No. 29474160) & "Polymeric metal complex catalysts
文摘In the course of investigating the catalytic behavior of metal complexes for ring opening metathesis polymerization of cycloolefins, metathesis, hydroformylation and selective hydrogenation of olefins experimental results time and again indicate the presence of effects of macromolecular supports - the utilization of macromolecular supports increases obviously the activity, selectivity, and stability of the catalysts and so as to increase the conversion of substrates, yields of reactions, properties of formed polymers and so on. Discussed these effects on the basis of the authors' experiments. (Author abstract) 18 Refs.
