The influence of several anions on Fe-based Fischer-Tropsch catalyst, used in the synthesis of light olefins from synthesis gas, was studied. The results indicated that the addition of anions resulted in the reduction...The influence of several anions on Fe-based Fischer-Tropsch catalyst, used in the synthesis of light olefins from synthesis gas, was studied. The results indicated that the addition of anions resulted in the reduction of catalytic activity. When the anion content in the catalyst was 500 ppm, the influence of different anions on the catalysis activity was as follows： S^2- 〉Cl^-〉SO4^2-〉NO3. The addition of S^2- improved the selectivity of total hydrocarbons in the products, and Cl^- reduced this selectivity but increased the olefin content in the total hydrocarbons at the same time. When the contents of S^2- and Clin the catalyst were less than 50 ppm, their influence could be ignored. The XRD results indicated that the addition of anions reduced the contents of α-Fe and FeaC, which were the active components in the catalyst.展开更多
The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperatur...The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperature of NMR experiment varies from 243 K to 283 K. After ethyl diazoacetate and styrene are added into the catalytic system, the process that the OTf - leaves from the central metal is observed from the change of the 19 F NMR spectra. Owing to the weakly coordinating behavior, trifluoromethanesulfonate ion can be easily removed from the central metal and replaced by substrates to form the reactive intermediate during the reaction. So that the catalytic reactivity can be improved greatly when the silver trifluoromethanesulfonate is added to the catalytic system.展开更多
The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon t...The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.展开更多
文摘The influence of several anions on Fe-based Fischer-Tropsch catalyst, used in the synthesis of light olefins from synthesis gas, was studied. The results indicated that the addition of anions resulted in the reduction of catalytic activity. When the anion content in the catalyst was 500 ppm, the influence of different anions on the catalysis activity was as follows： S^2- 〉Cl^-〉SO4^2-〉NO3. The addition of S^2- improved the selectivity of total hydrocarbons in the products, and Cl^- reduced this selectivity but increased the olefin content in the total hydrocarbons at the same time. When the contents of S^2- and Clin the catalyst were less than 50 ppm, their influence could be ignored. The XRD results indicated that the addition of anions reduced the contents of α-Fe and FeaC, which were the active components in the catalyst.
文摘The role of trifluoromethanesulfonate ion (OTf -) in asymmetric cyclopropanation of styrene catalyzed by ruthenium complex of chiral N, P ligand is investigated by in situ variable temperature 19 F NMR. The temperature of NMR experiment varies from 243 K to 283 K. After ethyl diazoacetate and styrene are added into the catalytic system, the process that the OTf - leaves from the central metal is observed from the change of the 19 F NMR spectra. Owing to the weakly coordinating behavior, trifluoromethanesulfonate ion can be easily removed from the central metal and replaced by substrates to form the reactive intermediate during the reaction. So that the catalytic reactivity can be improved greatly when the silver trifluoromethanesulfonate is added to the catalytic system.
基金Project(2018YFC1900304)supported by the National Key R&D Program of ChinaProject(2018SK2026)supported by the Key R&D Program of Hunan Province,ChinaProject(2017SK2420)supported by the Science and Technology of Hunan Province,China。
文摘The corrosion behaviors and electrochemical properties of Q235 A steel in the treated water containing corrosive halide anions(F-, Cl-) have been investigated with corrosion tests of static coupon and dynamic coupon testing, electrochemical measurement of open-circuit potential and linear sweep voltammetry. The results reveal that the existence of F-and Cl-ions in the simulated treated water accelerate the corrosion rate of Q235 A steel. The corrosion rate reaches maximum with F-concentration of 50 mg/L, Cl-concentration of 200 mg/L, respectively. However, Q235 A steel would passivate when an applied potential is added to the system. Meanwhile, the initiating passive potential becomes positive with F-, Cl-concentration increasing. There is a little influence of F-, Cl-concentration on the initiating passivation current density. Therefore, it is necessary to control F-, Cl-concentration in the treated water when it is recycled by the pipelines made of Q235 A steel.
