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
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.
