采用离子交换法对银杏壳中果胶进行提取。通过单因素试验和正交试验探讨了提取过程中各因素对果胶得率的影响,结果表明适宜工艺条件为:离子交换树脂用量7%,p H 2.0,提取温度85℃,提取时间2h,料液比1∶20(g∶m L)。在此工艺条件下,果胶...采用离子交换法对银杏壳中果胶进行提取。通过单因素试验和正交试验探讨了提取过程中各因素对果胶得率的影响,结果表明适宜工艺条件为:离子交换树脂用量7%,p H 2.0,提取温度85℃,提取时间2h,料液比1∶20(g∶m L)。在此工艺条件下,果胶得率为4.85%。展开更多
The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adso...The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adsorption. Catalytic activities were evaluated via the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The Pt dispersion and acidity of the Pt-supported USY catalyst were influenced by the addition of the promoters. The Pt-supported catalysts promoted by Cr, Al or Zn, especially by Cr, were catalytically much more stable and exhibited much higher catalytic activity and selectivity for isomerization of n-heptane than the catalysts without the dopant. Both the conversion and selectivity are discussed in relation with the physicochemical properties of catalysts.展开更多
文摘The Pt-supported USY zeolite catalysts doped with Cr, Al or Zn were prepared by impregnation, and characterized by XRD, low temperature nitrogen physisorption, H2-chemisorption and IR spectroscopy of the pyridine adsorption. Catalytic activities were evaluated via the hydroisomerization of n-heptane with an atmospheric fixed-bed reactor. The Pt dispersion and acidity of the Pt-supported USY catalyst were influenced by the addition of the promoters. The Pt-supported catalysts promoted by Cr, Al or Zn, especially by Cr, were catalytically much more stable and exhibited much higher catalytic activity and selectivity for isomerization of n-heptane than the catalysts without the dopant. Both the conversion and selectivity are discussed in relation with the physicochemical properties of catalysts.