Abstract:

Hβ zeolites were modified by immersion method with different phosphorus content solutions. The physicochemical properties of the samples were characterized by XRD, BET, NH3-TPD, MAS NMR techniques. The ethyl cyclohexane was used as a model compound to investigate the ring opening performance of the catalysts. The results show that modification with suitable amount of phosphorus can stabilize the framework aluminum of β zeolite, and improve the hydrothermal stability and activity. With the increase of the w(P2O5)/w(Al2O3), the relative crystallinity, specific surface area and retained acid amount were first increased and then decreased, and the reactivity and propylene yield as well. When the w(P2O5)/w(Al2O3) is 1.15, the hydrothermal stability and activity of molecular sieves achieve the optimal.

Key words: phosphorus modification, &beta, zeolite, naphthene, ring opening