The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relati...The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.展开更多
New 3 -oxo-benzoisothiazoline-2-acetamide 1, 1-dioxides (IIa-b) ware synthesizedand whose reaction with alkoxides was studied. The reaction results indicated that differentproducts were obtained owing to the different...New 3 -oxo-benzoisothiazoline-2-acetamide 1, 1-dioxides (IIa-b) ware synthesizedand whose reaction with alkoxides was studied. The reaction results indicated that differentproducts were obtained owing to the different time of reaction with alkoxides展开更多
Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy ) with 0.5equimolar chiral diol in THF (tetrahydrofuran) a...Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy ) with 0.5equimolar chiral diol in THF (tetrahydrofuran) at -78℃ at room temperature. All the complexes were characterized by elemental analysis, IR and MS spectra.展开更多
Tantalum(Ⅴ)propoxide(Ta(OPrn)5),isopropoxide(Ta(OPr i )5)and butoxide(Ta(OBu n )5)were synthesized by electro- chemical reactions of corresponding alcohol at sacrificial tantalum anode in the presence of tetraethylam...Tantalum(Ⅴ)propoxide(Ta(OPrn)5),isopropoxide(Ta(OPr i )5)and butoxide(Ta(OBu n )5)were synthesized by electro- chemical reactions of corresponding alcohol at sacrificial tantalum anode in the presence of tetraethylammonium chloride as a conductive additive.The pure products were isolated by reduced pressure distillation under 5 kPa.The crystal of Ta(OPri)5 was obtained by recrystallization from hexane at-10℃.These samples were characterized by Fourier transform infrared spectra(FT-IR), Raman spectra,nuclear magnetic resonance spectra(NMR),TG/DTA and ICP-MS.The results show that direct electrochemical synthesis of metal alkoxides has a high current efficiency and electrolysis yield.These alkoxides have a high purity of 99.97%and can be directly used as the precursor of Ta2O5 films.展开更多
The preparation of yttria-stabilised zirconia (YSZ) sol and the mechanismsof sol formation and sol-gel transition have been studied. The YSZ sol was prepared viacontrolled hydration of propanol zirconia alkoxide doped...The preparation of yttria-stabilised zirconia (YSZ) sol and the mechanismsof sol formation and sol-gel transition have been studied. The YSZ sol was prepared viacontrolled hydration of propanol zirconia alkoxide doped with yttrium nitrite. The sol formation process and gelling time are affected by many parameters such as water content,acetic acid content and the amount of propanol. The stability of the sol can be greatlyimproved by adding appropriate polymer.展开更多
The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in abso...The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in absolute ethanol in the presence of a conductive additives. The anodic behaviour of Ti electrode in ethanol was investigated by using cyclic voltammetry（CV）. These metal alkoxides were characterized by FTIR spectra. The results show that direct electrochemical synthesis of metal alkoxides have a high current efficiency and electrolysis yield. These alkoxides have a high purity and can be directly used as the precursor of nanosize oxides prepared by sol-gel procedure. The anodic behaviour of Ti electrode in alcohol is markedly the feature of the pitting corrosion. The passivation of Ti anode would occur in the presence of trace water.展开更多
文摘The structural characteristics of different alkoxides of Y. Ba and Cu are studied with quantum chemi-cal CNDO /2 calculations. The relative hydrolysis rate coefficients k_M of them are obtained according tothe relationship between frontier orbitals and organic chemical reactions. Based on the above results. properexperimental conditions for the preparation of homogeneous ultra-purity. submicro high-T_cYBa_2Cu_3O_(7-δ) superconducting powders are proposed.
文摘New 3 -oxo-benzoisothiazoline-2-acetamide 1, 1-dioxides (IIa-b) ware synthesizedand whose reaction with alkoxides was studied. The reaction results indicated that differentproducts were obtained owing to the different time of reaction with alkoxides
文摘Three new chiral binuclear organolanthanide alkoxides containing cyclopentadienyl ligand have been synthesised by the reaction of Cp3Ln (Cp=C5H5; Ln=Yb, Y, Dy ) with 0.5equimolar chiral diol in THF (tetrahydrofuran) at -78℃ at room temperature. All the complexes were characterized by elemental analysis, IR and MS spectra.
基金Project(2007AA03Z425)supported by the Hi-tech Research and Development Program of ChinaProject(50404011)supported by the National Natural Science Foundation of China
文摘Tantalum(Ⅴ)propoxide(Ta(OPrn)5),isopropoxide(Ta(OPr i )5)and butoxide(Ta(OBu n )5)were synthesized by electro- chemical reactions of corresponding alcohol at sacrificial tantalum anode in the presence of tetraethylammonium chloride as a conductive additive.The pure products were isolated by reduced pressure distillation under 5 kPa.The crystal of Ta(OPri)5 was obtained by recrystallization from hexane at-10℃.These samples were characterized by Fourier transform infrared spectra(FT-IR), Raman spectra,nuclear magnetic resonance spectra(NMR),TG/DTA and ICP-MS.The results show that direct electrochemical synthesis of metal alkoxides has a high current efficiency and electrolysis yield.These alkoxides have a high purity of 99.97%and can be directly used as the precursor of Ta2O5 films.
文摘The preparation of yttria-stabilised zirconia (YSZ) sol and the mechanismsof sol formation and sol-gel transition have been studied. The YSZ sol was prepared viacontrolled hydration of propanol zirconia alkoxide doped with yttrium nitrite. The sol formation process and gelling time are affected by many parameters such as water content,acetic acid content and the amount of propanol. The stability of the sol can be greatlyimproved by adding appropriate polymer.
文摘The direct electrochemical synthesis of metal alkoxides [Ti（OEt）4, Ti（OPr-i）4, Ti（OBu）4, Ti（OEt）2（acac）, Cu（OEt）2, Cu（OBu）2, Mg（OEt）2 and Ni（OEt）2] were studied by anode dissolution of metals in absolute ethanol in the presence of a conductive additives. The anodic behaviour of Ti electrode in ethanol was investigated by using cyclic voltammetry（CV）. These metal alkoxides were characterized by FTIR spectra. The results show that direct electrochemical synthesis of metal alkoxides have a high current efficiency and electrolysis yield. These alkoxides have a high purity and can be directly used as the precursor of nanosize oxides prepared by sol-gel procedure. The anodic behaviour of Ti electrode in alcohol is markedly the feature of the pitting corrosion. The passivation of Ti anode would occur in the presence of trace water.
