Phosphorus promoted HZSM-5 zeolites for the coupling transformation of methanol with 1-butene to propylene

Phosphorus promoted HZSM-5 zeolites (P-HZSM-5) were prepared by synthetic methods of incipient wetness impregnation and in situ synthesis, respectively. This was characterized by the means of powder X-ray diffraction (XRD), scanning electron microscopy (SEM), Brunauer–Emmett–Teller method (BET), thermogravimetry (TG), and NH₃-TPD. The P-HZSM-5 zeolite prepared by incipient wetness impregnation has a large specific surface area and pore size, and the weak acidity is remarkably increased. The catalytic activity of P-HZSM-5 for the coupling transformation of methanol with 1-butene to propylene was investigated. Under the reaction conditions of temperature at 550 °C, pressure at 0.4 MPa, space velocity at 1800 mL/(g_cat h), and mole ratio of CH₃OH/C₄H₈ at 1:1, the conversion of C₄H₈ can reach to 75.8%, and the selectivity and yield of propylene are 42.2% and 31.9%, respectively.