Polyurea microcapsules containing NiCl2 were prepared by interracial polymerization between diisocyanate and water with triethylamine as a catalyst in water-in-oil emulsion system. The influence of preparation conditi...Polyurea microcapsules containing NiCl2 were prepared by interracial polymerization between diisocyanate and water with triethylamine as a catalyst in water-in-oil emulsion system. The influence of preparation conditions such as the dosage and feed mode of the catalyst, concentration of the encapsulated NiCl2, and concentration and structure of diisocyanates on the breakage of the microcapsules have been evaluated. The results show thatbreakage is strongly dependent on the rate of polymerization and stability of initial emulsion. The improved microcapsules with low breakage have been produced under the optimum conditions. Furthermore, the obtained microcapsules capsules immobilizing NiCl2 as a recyclable catalyst is successfully used in benzaldehyde reduction.展开更多
α-Ni(OH)2 was synthesized from a NiCl2 solution by electrodeposition method.In order to conduct a systematic study on the effects of experimental parameters,a series of electrolyte initial pH values,current densities...α-Ni(OH)2 was synthesized from a NiCl2 solution by electrodeposition method.In order to conduct a systematic study on the effects of experimental parameters,a series of electrolyte initial pH values,current densities,electrodeposition temperatures,and electrodeposition time were used.Cyclic voltammetry results demonstrated a side reaction of Ni^2++2e→Ni.The X-ray diffraction analysis,Fourier-transform infrared spectrum,and the color of the product showed that pureα-Ni(OH)2 could be obtained in the initial pH value range of 2−5.86,current density range of 10−25 mA/cm^2,electrodeposition temperature range of 25−35℃,and electrodeposition time range of 1.0−3.0 h.When electrodeposition temperature increased to 45℃,a mixture ofα-Ni(OH)2 and metallic Ni was obtained.A current density higher than 30 mA/cm^2 resulted in the sample with features ofβ-Ni(OH)2.A small amount of metallic Ni existed in the as-prepared sample when current density decreased to 5 mA/cm^2.A slight increase of electrolyte pH was observed with increasing initial solution pH and current density.Electrodeposition mass revealed a slight decrease with initial pH decreasing and showed an almost linear increase with current density increasing.The slope of the curve for electrodeposition mass versus electrodeposition time remained stable in the first 2.0 h and then decreased.展开更多
基金Supported by the National Natural Science Foundation of China （No.20576045）, the Opening Foundation of Zhejiang Provincial Top Key Discipline, and the Program for New Century Excellent Talents in University （No.NCET-06-740）.
文摘Polyurea microcapsules containing NiCl2 were prepared by interracial polymerization between diisocyanate and water with triethylamine as a catalyst in water-in-oil emulsion system. The influence of preparation conditions such as the dosage and feed mode of the catalyst, concentration of the encapsulated NiCl2, and concentration and structure of diisocyanates on the breakage of the microcapsules have been evaluated. The results show thatbreakage is strongly dependent on the rate of polymerization and stability of initial emulsion. The improved microcapsules with low breakage have been produced under the optimum conditions. Furthermore, the obtained microcapsules capsules immobilizing NiCl2 as a recyclable catalyst is successfully used in benzaldehyde reduction.
基金Project(U1710257)supported by the National Natural Science Foundation of China。
文摘α-Ni(OH)2 was synthesized from a NiCl2 solution by electrodeposition method.In order to conduct a systematic study on the effects of experimental parameters,a series of electrolyte initial pH values,current densities,electrodeposition temperatures,and electrodeposition time were used.Cyclic voltammetry results demonstrated a side reaction of Ni^2++2e→Ni.The X-ray diffraction analysis,Fourier-transform infrared spectrum,and the color of the product showed that pureα-Ni(OH)2 could be obtained in the initial pH value range of 2−5.86,current density range of 10−25 mA/cm^2,electrodeposition temperature range of 25−35℃,and electrodeposition time range of 1.0−3.0 h.When electrodeposition temperature increased to 45℃,a mixture ofα-Ni(OH)2 and metallic Ni was obtained.A current density higher than 30 mA/cm^2 resulted in the sample with features ofβ-Ni(OH)2.A small amount of metallic Ni existed in the as-prepared sample when current density decreased to 5 mA/cm^2.A slight increase of electrolyte pH was observed with increasing initial solution pH and current density.Electrodeposition mass revealed a slight decrease with initial pH decreasing and showed an almost linear increase with current density increasing.The slope of the curve for electrodeposition mass versus electrodeposition time remained stable in the first 2.0 h and then decreased.
