Monodisperse cobalt nanoparticles with relatively high coercivities were synthesized by thermal decomposition of cobalt acetate for the application of ultra-high density magnetic recording media. Without using any red...Monodisperse cobalt nanoparticles with relatively high coercivities were synthesized by thermal decomposition of cobalt acetate for the application of ultra-high density magnetic recording media. Without using any reducing agent, Co nanoparticles of 13.9-21.3 nm in size were prepared using various protecting agents and a high boiling point solvent trioctylamine. The Co nanoparticles prepared with the mixture of oleic acid, oleylamine, and polyvinylpyrrolidone （PVP） showed clear crystalline structure of face centered cubic, and their coercivity was measured to be 27.2 kA/m. PVP was effective in controlling particle growth while hindering agglomeration between the particles. The as-prepared Co nanoparticles with a moderate coercivity can be applicable to patterned media.展开更多
Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol ...Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol with Cu（Ⅱ） chloride dihydrate in anhydrous methanol. The structures of I and Ⅱ were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Co3（C51H66N3O16）]2（OAc）, monoclinic, space group P21, a = 15.022（3）, b = 14.242（3）, c = 28.922（6） A, β = 98.944（4）°, V = 6112（2） A3, Z = 4, Dc = 1.339 g/cm^3, the final R = 0.0860 for 21906 observed reflections with I 〉 2（I）. For Ⅱ： Cu2[C24H58N4O7Cl]Cl, orthorhombic, space group P212121, a = 6.1861（13）, b = 20.838（4）, c = 28.274（6） , V = 3644.6（13） 3, Z = 4, Dc = 1.310 g/cm^3, the final R = 0.0642 for 11106 observed reflections with I 〉 2（I）. The complexes were then used to catalyze the Henry reaction and catalytic activity determined by 1H NMR.展开更多
Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results...Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results show that the purity of the product by the modified method is higher compared with that by the previous methods. A complete characterization of the as-prepared samples was performed by means of X-ray powder diffraction, IR spectroscopy, scanning electron microscope, as well as magnetic measurement. The facile and effective approach for the preparation of this compound in this study is very interesting and important because it has wide application in the field of anionic exchange reaction for the synthesis of hybrid organic-inorganic compounds.展开更多
Thin PVA/cobalt acetate composite fibers were prepared by using sol-gel processing and electrospinning technique. After calcination of the above precursor fibers, Co3O4 nanofibers with a diameter of 50-150 nm could be...Thin PVA/cobalt acetate composite fibers were prepared by using sol-gel processing and electrospinning technique. After calcination of the above precursor fibers, Co3O4 nanofibers with a diameter of 50-150 nm could be successfully obtained. The fibers were characterized by SEM, FT-IR, WAXD, respectively.展开更多
An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-c...An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）_2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）_2 were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）_2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.展开更多
基金supported by the Scientific Research Foundation for the Returned Overseas Chinese Scholars,State Education Ministrythe National Natural Science Foundation of China (No. 50774010)
文摘Monodisperse cobalt nanoparticles with relatively high coercivities were synthesized by thermal decomposition of cobalt acetate for the application of ultra-high density magnetic recording media. Without using any reducing agent, Co nanoparticles of 13.9-21.3 nm in size were prepared using various protecting agents and a high boiling point solvent trioctylamine. The Co nanoparticles prepared with the mixture of oleic acid, oleylamine, and polyvinylpyrrolidone （PVP） showed clear crystalline structure of face centered cubic, and their coercivity was measured to be 27.2 kA/m. PVP was effective in controlling particle growth while hindering agglomeration between the particles. The as-prepared Co nanoparticles with a moderate coercivity can be applicable to patterned media.
文摘Two novel L-amino alcohol coordination cobalt and copper complexes I and Ⅱ were obtained separately from the direct reaction of L-plenylglycinol with Co（Ⅱ） acetate tetrahydrate in anhydrous ethanol and L-leucinol with Cu（Ⅱ） chloride dihydrate in anhydrous methanol. The structures of I and Ⅱ were determined by single-crystal X-ray diffraction and further characterized by elemental analysis and IR. For I： [Co3（C51H66N3O16）]2（OAc）, monoclinic, space group P21, a = 15.022（3）, b = 14.242（3）, c = 28.922（6） A, β = 98.944（4）°, V = 6112（2） A3, Z = 4, Dc = 1.339 g/cm^3, the final R = 0.0860 for 21906 observed reflections with I 〉 2（I）. For Ⅱ： Cu2[C24H58N4O7Cl]Cl, orthorhombic, space group P212121, a = 6.1861（13）, b = 20.838（4）, c = 28.274（6） , V = 3644.6（13） 3, Z = 4, Dc = 1.310 g/cm^3, the final R = 0.0642 for 11106 observed reflections with I 〉 2（I）. The complexes were then used to catalyze the Henry reaction and catalytic activity determined by 1H NMR.
基金Supported by the President Fund of Xi'an Technological University,China(No.XAGDXJJ1009)
文摘Layered hydroxide metal acetate Co2（OH）3（CH3COO）·H2O with an interlayer spacing of 1.282 nm has been synthesized by a novel method which is employed in ethanol-aqueous mixed solvents media. Experiment results show that the purity of the product by the modified method is higher compared with that by the previous methods. A complete characterization of the as-prepared samples was performed by means of X-ray powder diffraction, IR spectroscopy, scanning electron microscope, as well as magnetic measurement. The facile and effective approach for the preparation of this compound in this study is very interesting and important because it has wide application in the field of anionic exchange reaction for the synthesis of hybrid organic-inorganic compounds.
文摘Thin PVA/cobalt acetate composite fibers were prepared by using sol-gel processing and electrospinning technique. After calcination of the above precursor fibers, Co3O4 nanofibers with a diameter of 50-150 nm could be successfully obtained. The fibers were characterized by SEM, FT-IR, WAXD, respectively.
文摘An attempt has been made to prepare terephthalic acid（TPA） by solvent-free oxidation of p-xylene（PX） with air over tetra（pchlorophenylporphinato） manganese chloride（T（p-Cl）PPMnCl） and cobalt acetate.The co-catalysis between T（p-Cl）PPMnCl and Co（OAc）_2 has been discovered under solvent-free conditions.TPA yield could be increased significantly when T（p-Cl）PPMnCl and Co（OAc）_2 were used together.The addition of T（p-Cl）PPMnCl into the reaction mixture over Co（OAc）_2 significantly accelerated the rate-determining step of the oxidation process of PX to TPA.The effect of temperature on reaction was also investigated.
