Research On The Preparation And Catalytic Performance Of M-MCM-48 (M=Mo,Al) Catalyst For N-Heptane Hydroisomerization

Mesoporous material MCM-48 has a three-dimensional cubic Ia3d mesostructure,high surface area,large pore volume,and single pore distribution,which can allow larger molecules or groups to enter their pores and effectively prevent pore blockage.However,pure silicon MCM-48 lacks active sites,weak acidity sites,and poor stability,which seriously limits its application in catalytic reactions.Therefore,it has important research value to the introduction of active components into the surface or skeleton of pure silicon MCM-48 to synthesize modified MCM-48 with strong acidity and high catalytic activity.In current paper,M-MCM-48?M=Mo,Al?catalysts were synthesized by in-situ doping method.The catalytic performance of M-MCM-48?M=Mo,Al?catalyst was investigated by using n-heptane isomerization as a probe.The effects of metal doping amount,reaction temperature and reaction time on the performance of isomerization of n-heptane were investigated in detail.The catalytic activity of Al-MCM-48 catalyst is higher than Mo-MCM-48 catalyst according to experimental results.The conversion of n-heptane and the selectivity of iso-heptane of Al-MCM-48 were 34.16%and 67.47%,respectively.In current paper,Ni/M-MCM-48?M=Mo,Al?bi-functional catalyst was prepared by impregnation method with metal Ni as active component.The catalytic performance of Ni/M-MCM-48?M=Mo,Al?catalyst was investigated by using n-heptane isomerization as a probe.The catalytic activity of Ni/Al-MCM-48 catalyst is higher than Ni/Mo-MCM-48catalyst according to experimental results.The influences of preparation conditions,reduction conditions and reaction conditions on the performance of n-heptane isomerization reaction were investigate.As results show that the catalytic performance of Ni/Al-MCM-48 catalyst reached the optimum when the metal load is 2%,the calcination temperature is 400 ^oC,the reduction temperature is 400 ^oC,the reduction time is 180 min,the reaction temperature is240 ^oC,and the reaction time is 140 min and the weight hourly space velocity is 6.8 h^-1.The conversion of n-heptane and the selectivity of iso-heptane were 44.89%and 86.45%,respectively.