Phosphorous Modified High Silica ZSM-5 Spherical Catalyst and Its Reaction on Methanol to Propylene

Phosphorous modified high silica ZSM-5 catalysts were synthesized by infusion method. XRD BET and NH₃-TPD results showed that phosphorous compounds were loaded uniformly on the surface of catalyst and de-aluminated pore surface was observed. The strong acids of phosphorous modified catalyst decreased and the weak acids increased. It also revealed from the results of methanol to propylene reaction that the phosphorous compounds in high silica ZSM-5 catalysts could suppress the hydrogen transfer reaction and increase the propylene selectivity. But the activity of catalysts would decrease rapidly when the phosphorous was over-loaded.