A new kind of solid acid based on heteropolyacid proved be a useful catalyst in the synthesis of cyclohexyl formate.The new catalyst HPAS/TiO2-WO3 was based on heteropolyacid supported on mixed metal oxides bymicrowav...A new kind of solid acid based on heteropolyacid proved be a useful catalyst in the synthesis of cyclohexyl formate.The new catalyst HPAS/TiO2-WO3 was based on heteropolyacid supported on mixed metal oxides bymicrowave and ultrasonic method. The catalyst was characterized through TEM,TG-DTA,and IR. Data show that catalyst is very active in synthesis reaction of cyclohexyl formate even at mild temperature. Under optimal conditions,the yield of cyclohexyl formate was about 85.4%.展开更多
By using photoacoustic calorimetry, a photoacoustic measurement system is applied to determine the Co-C bond dissociation energy of n C4H9Co(Salen)H2O, which is 116±8kJ·mol-1. This value is in agreement with...By using photoacoustic calorimetry, a photoacoustic measurement system is applied to determine the Co-C bond dissociation energy of n C4H9Co(Salen)H2O, which is 116±8kJ·mol-1. This value is in agreement with the activation enthalpy of the Co-C bond homolytic cleavage reaction that obtained by the kinetic method.展开更多
离子交换法制备的Fe-ZSM-5和K-Fe-ZSM-5分子筛,经不同温度水热处理后作为催化剂应用于N2O为氧化剂的苯一步氧化制取苯酚反应中。实验中,采用XRD、N2-吸附仪、NH3-TPD、27Al MAS NMR、FT-IR、UV-vis和H2-TPR等方法对催化剂进行表征。结...离子交换法制备的Fe-ZSM-5和K-Fe-ZSM-5分子筛,经不同温度水热处理后作为催化剂应用于N2O为氧化剂的苯一步氧化制取苯酚反应中。实验中,采用XRD、N2-吸附仪、NH3-TPD、27Al MAS NMR、FT-IR、UV-vis和H2-TPR等方法对催化剂进行表征。结果显示:离子交换制备的Fe-ZSM-5分子筛,部分Fe离子以Fe2O3形式负载于分子筛的孔道中。经水热处理,分子筛骨架脱铝导致Brnsted酸性位减少,而Fe2O3离子发生迁移形成活性Fe离子位。在苯一步氧化制苯酚反应中,N2O分子吸附于Fe离子位生成α-O。活性评价结果显示,水热处理前后,催化剂分解N2O性能不变,但苯酚选择性随水热处理温度的升高而逐渐降低。此外,K离子的引入将导致催化剂选择性的降低。展开更多
In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrosta...In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrostatic field effect on the C 1s core ionization energies of saturated molecules were evaluated,based on the topological electronegativity index TEI,the atomic electronegativity χP and the polarizability α.The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond.The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X.The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom.Further,the shielding effect ΔSi of the C 1s electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect.By introducing the ΔSi into the Slater model,a Slater-like model was obtained for calculating the C 1s core ionization energy E1,C of saturated molecules,whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C 1s core ionization energies is only 0.094eV for 81 saturated molecules.Also the cross-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99928,the average absolute error between the predicted and the experimental values is only 0.105 eV).展开更多
文摘A new kind of solid acid based on heteropolyacid proved be a useful catalyst in the synthesis of cyclohexyl formate.The new catalyst HPAS/TiO2-WO3 was based on heteropolyacid supported on mixed metal oxides bymicrowave and ultrasonic method. The catalyst was characterized through TEM,TG-DTA,and IR. Data show that catalyst is very active in synthesis reaction of cyclohexyl formate even at mild temperature. Under optimal conditions,the yield of cyclohexyl formate was about 85.4%.
文摘By using photoacoustic calorimetry, a photoacoustic measurement system is applied to determine the Co-C bond dissociation energy of n C4H9Co(Salen)H2O, which is 116±8kJ·mol-1. This value is in agreement with the activation enthalpy of the Co-C bond homolytic cleavage reaction that obtained by the kinetic method.
文摘离子交换法制备的Fe-ZSM-5和K-Fe-ZSM-5分子筛,经不同温度水热处理后作为催化剂应用于N2O为氧化剂的苯一步氧化制取苯酚反应中。实验中,采用XRD、N2-吸附仪、NH3-TPD、27Al MAS NMR、FT-IR、UV-vis和H2-TPR等方法对催化剂进行表征。结果显示:离子交换制备的Fe-ZSM-5分子筛,部分Fe离子以Fe2O3形式负载于分子筛的孔道中。经水热处理,分子筛骨架脱铝导致Brnsted酸性位减少,而Fe2O3离子发生迁移形成活性Fe离子位。在苯一步氧化制苯酚反应中,N2O分子吸附于Fe离子位生成α-O。活性评价结果显示,水热处理前后,催化剂分解N2O性能不变,但苯酚选择性随水热处理温度的升高而逐渐降低。此外,K离子的引入将导致催化剂选择性的降低。
文摘In this paper,Topological Electronegativity Index (TEI) was developed to express the relatively power of an group in a molecule to attract electrons to itself.The charge effect,the relaxation effect and the electrostatic field effect on the C 1s core ionization energies of saturated molecules were evaluated,based on the topological electronegativity index TEI,the atomic electronegativity χP and the polarizability α.The charge effect was scaled by the topological electronegativity index discrepancy between the C and X (X is atom or group) in the C-X bond.The relaxation effect (induced dipole) was scaled by the charge on the ionized carbon atom together with the polarizabiliy of the X.The electrostatic field effect was scaled by the charges on the atoms attached directly to the ionized carbon atom.Further,the shielding effect ΔSi of the C 1s electron in the saturated molecules was expressed by the charge effect and the relaxation effect together with the electrostatic field effect.By introducing the ΔSi into the Slater model,a Slater-like model was obtained for calculating the C 1s core ionization energy E1,C of saturated molecules,whose correlation coefficient r is 0.99943 and the average absolute error between the calculated and the experimental C 1s core ionization energies is only 0.094eV for 81 saturated molecules.Also the cross-correlation was tested by the leave-one-out (LOO) cross-validation method,and the obtained model has good predictive ability and stability (the correlation coefficient rcv is 0.99928,the average absolute error between the predicted and the experimental values is only 0.105 eV).
