Preparation And Catalytic Property Of Pillared Montmorillonite Materials

Pillared clay is a kind of the mineral materials, which is synthesized by pillaring inorganic polycations or organic ionic groups (molecules) into clay minerals. Modified clay is a two-dimensional mineral material with large surface area, high thermal stability, strong acidity and variable pore size; therefore it is widely used in such field as petrochemical, sewerage treatment, and antibacterial materials. Ca-montmorillonite was from Xinyang, Henan province and was sodium-modified as raw material. Si and Si/Ti-pillaring agents were prepared via sol-gel method, Si/Fe, Si/Al, Fe/Al, Ni/Al, Cr/Al and Zr/Al-pillaring agents were prepared via copolymerization. Silicon and the aluminum series pillared montmorillonite were prepared via ion-exchange method under optimal conditions. The basal spacing d(001) value was considered as standard to judge the pillaring effect. In order to research the optimum conditions of cyclohexanol dehydration over catalyst pillared montmorillonite, the experiments were done under different catalyst quantity, reaction temperature and time. Fixed-bed microreactor was used to evaluate the catalytic activity of pillared montmorillonite. Pillared montmorillonite hydroxy cation size can be judged according to the value of the layer spacing formed, the maximum is Si/Al pillared montmorillonite and the minimum is Si pillared montmorillonite. When mass fraction of pillared montmorillonite to cyclohexanol was10%, after carrying the reaction for1h at190℃, the highest cyclohexene yield could be realized. The aluminum series pillared montmorillonite as the catalyst cyclohexene recoveries generally greater than the recovery of silicon series. The cracking catalytic activity of pillared montmorillonite and he basal spacing d(001) value have a certain relationship. Cr/Al pillared montmorillonite showed the highest activity; Si/Al pillared montmorillonite is on the contrary.