摘要
The mesoporous materials supported zirconium （Zr-MCM-48） and magnesium （Mg-MCM-48） with three-dimen- sional pore structures and different Zr or Mg contents were prepared via the hydrothermal method, respectively. The prepared samples were characterized by means of X-ray diffraction （XRD）, scanning electron microscope （SEM）, transmission electron microscope （TEM）, Fourier transform infrared spectroscopy （FT-IR）, NH3 temperature programmed desorption （NH3-TPD） and N2 adsorption-desorption. The XRD, TEM and N2 adsorption-desorption results suggested that M-MCM-48 （where M = Zr, Mg） samples still maintained typical cubic mesoporous framework of MCM-48, with slight decrease of specific surface areas and mesopore orders. The isomerization of n-heptane was carried out as a probe reaction at various factors including the zirconium or magnesium content, reaction time, reaction temperature and weight hourly space veloc- ity （WHSV）. Preliminary results demonstrated that the Mg-MCM-48 catalyst exhibited a higher catalytic activity with a maximum heptane conversion of 91.5% and a corresponding isomerization selectivity of 72.3% as compared to that of Zr- MCM-48. However, for catalytic stability of Mg-MCM-48 for n-heptane isomerization was poorer than Zr-MCM-48, because the Mg-MCM-48 catalyst could maintain a relatively high catalytic activity for only 130 rain, while the Zr-MCM-48 catalyst could maintain a relatively high catalytic activity for more than 190 min without any obvious decrease in performance.
The mesoporous materials supported zirconium(Zr-MCM-48) and magnesium(Mg-MCM-48) with three-dimensional pore structures and different Zr or Mg contents were prepared via the hydrothermal method, respectively. The prepared samples were characterized by means of X-ray diffraction(XRD), scanning electron microscope(SEM), transmission electron microscope(TEM), Fourier transform infrared spectroscopy(FT-IR), NH_3 temperature programmed desorption(NH_3-TPD) and N_2 adsorption-desorption. The XRD, TEM and N_2 adsorption-desorption results suggested that M-MCM-48(where M = Zr, Mg) samples still maintained typical cubic mesoporous framework of MCM-48, with slight decrease of specific surface areas and mesopore orders. The isomerization of n-heptane was carried out as a probe reaction at various factors including the zirconium or magnesium content, reaction time, reaction temperature and weight hourly space velocity(WHSV). Preliminary results demonstrated that the Mg-MCM-48 catalyst exhibited a higher catalytic activity with a maximum heptane conversion of 91.5% and a corresponding isomerization selectivity of 72.3% as compared to that of ZrMCM-48. However, the catalytic stability of Mg-MCM-48 for n-heptane isomerization was poorer than Zr-MCM-48, because the Mg-MCM-48 catalyst could maintain a relatively high catalytic activity for only 130 min, while the Zr-MCM-48 catalyst could maintain a relatively high catalytic activity for more than 190 min without any obvious decrease in performance.
基金
supported by the postdoctoral programme for chemical engineering and technology of Northeast Petroleum University
the Youth Fund of Northeast Petroleum University(grant number NEPUQN2015-1-08)
the Cultivation Fund of Northeast Petroleum University [grant number 2017PYYL-03]
the Daqing Science and Technology Plan Projects [grant number szdfy-2015-04]
the College Students’ Innovative Entrepreneurial Training Plan Projects of Heilongjiang Province [grant number 201710220030]
