Construction of HZSM-5 Zeolite in Medium Containing Fluoride Ion and Its Performance in the Conversion of Methanol to Propylene

In this research, HZSM-5 zeolite was made in medium containing fluoride ions, and its performance in the process of methanol to propylene conversion was investigated. Potassium fluoride was used as the supplying material for this ion. Physical-chemical properties of catalysts were determined by using XRD, FESEM, N2 adsorption/desorption and NH3-TPD analysis. The XRD pattern confirmed the formation of crystalline structure associated with zeolite HZSM-5 in potassium fluoride-synthesized zeolite (F-HZSM-5 specimen). FESEM images of F-HZSM-5 zeolite showed a change in morphology and an increase in particles size compared to the reference sample HZSM-5. Results of the NH3-TPD analysis showed a reduction in the concentration of total acid sites in the F-HZSM-5 zeolite. The activity of the samples in a fixed-bed reactor and in the same operating conditions was investigated. The F-HZSM-5 catalyst showed less lifetime in comparison with the reference sample. However, this catalyst over a period of 10 days had an average selectivity of propylene and a propylene/ethylene ratio of 41.8 and 10.9, respectively.