TPPR and XPS characterizations were combined to study the reaction mechanism of CO2reforming of methane to syngas over Co/γ-Al2O3 catalysts. CH4 shows a tendency to form surface carbons by deep dissociation at high t...TPPR and XPS characterizations were combined to study the reaction mechanism of CO2reforming of methane to syngas over Co/γ-Al2O3 catalysts. CH4 shows a tendency to form surface carbons by deep dissociation at high temperatures. CO2 dissociation reaction also occurs at >673K. It is believed that carbide carbons are active species to generate CO by rcacting with o atoms dissociated from CO2. In the reaction,Co(0) particles are responsible for dissociating CH4 to form active C. abstracting an O atom from CO2 molecule, and transferring O atom to C to form CO.展开更多
The reaction mechanism of ammonia with formaldehyde was investigated by using the intrinsic reaction coordinate(IRC)method on the ab initio RHF/STO-3G basis set. our results indicate that the reaction proceeds in two ...The reaction mechanism of ammonia with formaldehyde was investigated by using the intrinsic reaction coordinate(IRC)method on the ab initio RHF/STO-3G basis set. our results indicate that the reaction proceeds in two stages:the first step yields the molecular complex and the second one is the rearrangement from molecular complex to the reaction proauct.展开更多
The cycloaddition reactions between ketene or substituted ketenes and cyelopentadiene have been studied theoretically by means of the semiempirical AMI method.Three different substituted ketenes have been selected and...The cycloaddition reactions between ketene or substituted ketenes and cyelopentadiene have been studied theoretically by means of the semiempirical AMI method.Three different substituted ketenes have been selected and ten transition states,corresponding to different approach geometries have been located and characterized,The regioselectivity and stereoselectivity of the reactions are correctly predicted by the calculations and the reaction mechanisms are analyzed in terms of electronic and steric effects of the substitutents on the reacting ketene and cyc-lopentadiene.展开更多
文摘TPPR and XPS characterizations were combined to study the reaction mechanism of CO2reforming of methane to syngas over Co/γ-Al2O3 catalysts. CH4 shows a tendency to form surface carbons by deep dissociation at high temperatures. CO2 dissociation reaction also occurs at >673K. It is believed that carbide carbons are active species to generate CO by rcacting with o atoms dissociated from CO2. In the reaction,Co(0) particles are responsible for dissociating CH4 to form active C. abstracting an O atom from CO2 molecule, and transferring O atom to C to form CO.
基金This work was partly supported by the National Science Foundation of China
文摘The reaction mechanism of ammonia with formaldehyde was investigated by using the intrinsic reaction coordinate(IRC)method on the ab initio RHF/STO-3G basis set. our results indicate that the reaction proceeds in two stages:the first step yields the molecular complex and the second one is the rearrangement from molecular complex to the reaction proauct.
文摘The cycloaddition reactions between ketene or substituted ketenes and cyelopentadiene have been studied theoretically by means of the semiempirical AMI method.Three different substituted ketenes have been selected and ten transition states,corresponding to different approach geometries have been located and characterized,The regioselectivity and stereoselectivity of the reactions are correctly predicted by the calculations and the reaction mechanisms are analyzed in terms of electronic and steric effects of the substitutents on the reacting ketene and cyc-lopentadiene.
