The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three ...The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three redution steps for the four heteropolyacids involved 2,2,2 electrons accompanied by the adition of 1,1,1 protons.A reduction mechanism has been proposed.The oxidation ability of these heteropolyacids increases with the increase of the substitution of vanadium.展开更多
In this paper,the phosphotungsten heteropoly acid catalytic membrance supported on porous titanium plate was prepared by dissolving the heteropoly acid in organic solvent then impregnating it on porous titanium plate....In this paper,the phosphotungsten heteropoly acid catalytic membrance supported on porous titanium plate was prepared by dissolving the heteropoly acid in organic solvent then impregnating it on porous titanium plate.The catalytic performance of the catalyst for synthesizing ethyl acetate was studied with self-made membrance reactor.The effects of the reaction temperature and the radio of acid to alcohol on the reaction were tested.The results show that on temperature 165℃～175℃ and n(acetic acid)/n(alcohol)=175,conversion of alcohol is 9073%,productivity of ester is 8744% and selectivity of ester is 9639%.It suggests that the catalyst may be a potential catalyst for the reaction.展开更多
Mixed oxide catalyst Cs 0 1 Fe 2Co 6BiMnMo 12 O x was prepared by the interprecipitation method,then the catalyst was calcined at different temperature.Selective oxidation of isobutene was carried out in a fixed bed r...Mixed oxide catalyst Cs 0 1 Fe 2Co 6BiMnMo 12 O x was prepared by the interprecipitation method,then the catalyst was calcined at different temperature.Selective oxidation of isobutene was carried out in a fixed bed reactor.The results showed that the catalyst has high catalytic activity.Under the optimum reaction conditions (n( C = 4)∶n(O 2)=1∶2 1∶4,space velocity=180h 1 ,T=360℃),the yield of methacrolein and methacrylic reached 80%,8%,respectively.The total yields of liquid products(methacrolein,methacrylic acid and acetic acid)reached about 90%.展开更多
The Cs0.1Cu0.2HXPVAs0.2Mo10Oy and Fe0.12HXPVAs0.3Mo11Oy catalysts were prepared by impregnation method and characterized by FT-IR and TPR.The propane oxidation on the catalysts were carried out in a continuous flow fi...The Cs0.1Cu0.2HXPVAs0.2Mo10Oy and Fe0.12HXPVAs0.3Mo11Oy catalysts were prepared by impregnation method and characterized by FT-IR and TPR.The propane oxidation on the catalysts were carried out in a continuous flow fixed-bed reactor.The result indicated that,under the conditions:V（N2）∶V（O2）∶V（C3H8）=2.2∶3.6∶1.2 θ=440℃,the catalysts performed in activity to a certain extent:over the catalyst of Cs0.1Cu0.2HXPVAs0.2Mo10Oy,the conversion for propane reach 72.92%,with a selectivity of 6.01% to acrylic acid and 2.91% to acetic acid;over Fe0.12HXPVAs0.3Mo11Oy catalyst,the conversion for propane was only 35.56%,but the selectivity for acrylic was as high as 12.15%,and acetic acid was 18.62%.The result showes that Cu could improve the conversion of propane,but could not inhibit the total oxidation product effectively,while Fe could enhance the selectivity for acrylic and acetic acid,but could not improve the conversion for propane.展开更多
文摘The redox properties of molybdovanadoarsenic heteropolyacids having keggin structure,H x[AsV nM O 12-n O 40 ]·YH 2O(n=1～4),were studied with polarography,cyclic voltammetry and XPS.It was ascertained that three redution steps for the four heteropolyacids involved 2,2,2 electrons accompanied by the adition of 1,1,1 protons.A reduction mechanism has been proposed.The oxidation ability of these heteropolyacids increases with the increase of the substitution of vanadium.
文摘In this paper,the phosphotungsten heteropoly acid catalytic membrance supported on porous titanium plate was prepared by dissolving the heteropoly acid in organic solvent then impregnating it on porous titanium plate.The catalytic performance of the catalyst for synthesizing ethyl acetate was studied with self-made membrance reactor.The effects of the reaction temperature and the radio of acid to alcohol on the reaction were tested.The results show that on temperature 165℃～175℃ and n(acetic acid)/n(alcohol)=175,conversion of alcohol is 9073%,productivity of ester is 8744% and selectivity of ester is 9639%.It suggests that the catalyst may be a potential catalyst for the reaction.
文摘Mixed oxide catalyst Cs 0 1 Fe 2Co 6BiMnMo 12 O x was prepared by the interprecipitation method,then the catalyst was calcined at different temperature.Selective oxidation of isobutene was carried out in a fixed bed reactor.The results showed that the catalyst has high catalytic activity.Under the optimum reaction conditions (n( C = 4)∶n(O 2)=1∶2 1∶4,space velocity=180h 1 ,T=360℃),the yield of methacrolein and methacrylic reached 80%,8%,respectively.The total yields of liquid products(methacrolein,methacrylic acid and acetic acid)reached about 90%.
文摘The Cs0.1Cu0.2HXPVAs0.2Mo10Oy and Fe0.12HXPVAs0.3Mo11Oy catalysts were prepared by impregnation method and characterized by FT-IR and TPR.The propane oxidation on the catalysts were carried out in a continuous flow fixed-bed reactor.The result indicated that,under the conditions:V（N2）∶V（O2）∶V（C3H8）=2.2∶3.6∶1.2 θ=440℃,the catalysts performed in activity to a certain extent:over the catalyst of Cs0.1Cu0.2HXPVAs0.2Mo10Oy,the conversion for propane reach 72.92%,with a selectivity of 6.01% to acrylic acid and 2.91% to acetic acid;over Fe0.12HXPVAs0.3Mo11Oy catalyst,the conversion for propane was only 35.56%,but the selectivity for acrylic was as high as 12.15%,and acetic acid was 18.62%.The result showes that Cu could improve the conversion of propane,but could not inhibit the total oxidation product effectively,while Fe could enhance the selectivity for acrylic and acetic acid,but could not improve the conversion for propane.
