The reaction mechanism of ethanol dehydration over SAPO-34 zeolite is investigated by using solid-state NMR spectroscopy. SAPO-34 zeolites with different Si contents are prepared and their acidities are characterized ...The reaction mechanism of ethanol dehydration over SAPO-34 zeolite is investigated by using solid-state NMR spectroscopy. SAPO-34 zeolites with different Si contents are prepared and their acidities are characterized by NMR experiments. The higher content of stronger Brønsted acid sites is correlated to the higher Si content. The adsorption of ethanol on the Brønsted acid sites in SAPO-34 leads to the formation of frustrated Lewis pairs(FLPs). Surface ethoxy species is observed by the dehydration of the FLP sites at room temperature, which can be further converted into ethene products. The decomposing of diethyl ether over Brønsted acid sites is responsible for the formation of ethoxy species at higher reaction temperatures. Triethyloxonium ions are formed in the reaction. A plausible reaction mechanism is proposed for the dehydration of ethanol over SAPO-34.展开更多
A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust ...A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust layers can be qualitatively reflected by the adsorption/dehydration rates. The specific surface area and porosity of rust layers can be calculated by a quantitative model. The results from the present method are consistent with electrochemical tests, N2 adsorption and X-ray diffraction analysis. The method characterizes the compactness of rust layers rather than that of corrosion products removed from the metal surfaces, which is generally practiced in classic N2 adsorption method. Furthermore, the method can reflect the compactness of inner rust layers, to which N2 adsorption is unavailable. The method provides a new approach for the study of rust layers.展开更多
基金This work was supported by the National Natural Science Foundation of China (Nos.22072165,U1932218,21991092,21733013,21773296)the National Natural Science Foundation of China-Royal Society(No.22061130202)the Project of the Youth Innovation Promotion Association of the Chinese Academy of Sciences(No.2021329).
文摘The reaction mechanism of ethanol dehydration over SAPO-34 zeolite is investigated by using solid-state NMR spectroscopy. SAPO-34 zeolites with different Si contents are prepared and their acidities are characterized by NMR experiments. The higher content of stronger Brønsted acid sites is correlated to the higher Si content. The adsorption of ethanol on the Brønsted acid sites in SAPO-34 leads to the formation of frustrated Lewis pairs(FLPs). Surface ethoxy species is observed by the dehydration of the FLP sites at room temperature, which can be further converted into ethene products. The decomposing of diethyl ether over Brønsted acid sites is responsible for the formation of ethoxy species at higher reaction temperatures. Triethyloxonium ions are formed in the reaction. A plausible reaction mechanism is proposed for the dehydration of ethanol over SAPO-34.
基金the National Natural Science Foundation of China(No.51571026)。
文摘A new method for evaluating the compactness of rust layers on steels has been proposed in the present study. The method includes adsorption and dehydration process of anhydrous ethanol. The protective ability of rust layers can be qualitatively reflected by the adsorption/dehydration rates. The specific surface area and porosity of rust layers can be calculated by a quantitative model. The results from the present method are consistent with electrochemical tests, N2 adsorption and X-ray diffraction analysis. The method characterizes the compactness of rust layers rather than that of corrosion products removed from the metal surfaces, which is generally practiced in classic N2 adsorption method. Furthermore, the method can reflect the compactness of inner rust layers, to which N2 adsorption is unavailable. The method provides a new approach for the study of rust layers.
