New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of ...New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures: molding, drying, calcination, and leaching. XRD, H2-TPR, as well as SEM technique were employed to study the physicochemical properties of the catalysts, and the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) was used as a probe to evaluate the performance of supported skeletal copper catalysts. The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 °C in air. A part of CuAl2 was oxidized to α-Al2O3, which was the main contributor to the strength of Raney-Cu/Al2O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process. The effects of reaction temperature, hydrogen pressure, LHSV, hydrogen-oil ratio, glycerol concentration, and alkaline additives on the catalytic performance were studied in water or ethanol, respectively. Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water, or 99.0% and 73.6% in the ethanol system, respectively, when the reaction was performed at a temperature of 215 °C, a H2 pressure of 3 MPa, a LHSV of 1.0 h-1, a hydrogen-oil ratio of 500, and a glycerol concentration of 20%(ethyl alcohol solution).展开更多
Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub&...Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.展开更多
以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO ...以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。展开更多
基金financially supported by the Importation and Development of High-Caliber Talents Project of Beijing Municipal Institutions(CIT&TCD20130325)the Project of Construction of Innovative Teams and Teacher Career Development for Universities and Colleges under Beijing Municipality (IDHT20180508)
文摘New supported Raney-Cu catalyst was prepared from pseudo-boehmite powder and copper aluminum alloy powder. It could be used in a continuous-flow fixed-bed reactor and it was also a good catalyst for hydrogenolysis of glycerol to propylene glycol after the two raw materials were processed by the following procedures: molding, drying, calcination, and leaching. XRD, H2-TPR, as well as SEM technique were employed to study the physicochemical properties of the catalysts, and the hydrogenolysis of glycerol to 1,2-propylene glycol (1,2-PDO) was used as a probe to evaluate the performance of supported skeletal copper catalysts. The test result indicated that CuAl2 was the main crystal phase of precursor after the dried strips were calcined at 850 °C in air. A part of CuAl2 was oxidized to α-Al2O3, which was the main contributor to the strength of Raney-Cu/Al2O3, while the remaining CuAl2 was converted to active skeletal copper after the leaching process. The effects of reaction temperature, hydrogen pressure, LHSV, hydrogen-oil ratio, glycerol concentration, and alkaline additives on the catalytic performance were studied in water or ethanol, respectively. Conversion of glycerol and selectivity of 1,2-PDO were 30.9% and 91.4% in water, or 99.0% and 73.6% in the ethanol system, respectively, when the reaction was performed at a temperature of 215 °C, a H2 pressure of 3 MPa, a LHSV of 1.0 h-1, a hydrogen-oil ratio of 500, and a glycerol concentration of 20%(ethyl alcohol solution).
文摘Silane coupling agent KH560 was used to modify the surface of nano-α-Al<sub>2</sub>O<sub>3</sub> in ethanol-aqueous solution with different proportions. The particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> was determined by nano-particle size analyzer, and the effects of nano-α-Al<sub>2</sub>O<sub>3</sub> content, ethanol-aqueous solution ratio and KH560 dosage on the dispersion and particle size of nano-α-Al<sub>2</sub>O<sub>3</sub> were investigated. The material structure before and after modification was determined by Fourier transform infrared spectroscopy (FTIR). Aqueous polyurethane resin and inorganic components are combined with modified nano-α-Al<sub>2</sub>O<sub>3</sub> dispersion to form chromium-free passivation solution. The solution is coated on the galvanized sheet, the adhesion and surface hardness are tested, the bonding strength of the coating and the surface hardness of the substrate are discussed. The corrosion resistance and surface morphology of the matrix were investigated by electrochemical test, neutral salt spray test and scanning electron microscope test. The chromium-free passivation film formed after the modification of nano-α-Al<sub>2</sub>O<sub>3</sub> increases the surface hardness of galvanized sheet by about 85%. The corrosion resistance of the film is better than that of a single polyurethane film. The results show that the surface hardness and corrosion resistance of polyurethane resin composite passivation film are significantly improved by the introduction of nano-α-Al<sub>2</sub>O<sub>3</sub>.
文摘以纳米ZrO 、微米Al O 为原料,采用无压烧结方式制备了ZTA 复相陶瓷。结果表明:nano-ZrO 的 2 2 3 2加入有利于制备细晶ZTA 复相陶瓷。此外,nano-ZrO 的加入对 Al O 陶瓷的显微结构也产生影响,ZrO 颗粒以 2 2 3 2“晶内型”和晶界型两种形式存在。合理的配方组成及制备工艺有利于 Z r O 以四方亚稳相存在。Z r O 含量为 2 23 0 w t % 时,其四方相含量可达 6 9 %,有利于应力诱导相变增韧,该 Z T A 复相陶瓷的抗弯强度、断裂韧性分别达到 604MPa、6.87MPa·m1/2。
