Isomerization of hydrocarbons over Pt supported on micro-mesoporous ZSM-5

Nanosized ZSM-5 with different Si/Al ratios, possessing both micro and mesopores, were synthesized by a hydrothermal method using tetrapropyl ammonium bromide (TPABr) as a template. The synthesised materials were characterized by different characterization methods to evaluate the phase purity, particle size, morphology, textural properties and acid strength. Pt (0.5 wt%) was loaded on the calcined (at 500 °C) ZSM-5 samples and evaluated for the isomerization of n-pentane, n-hexane and light naphtha. ZSM-5 as a catalyst showed higher conversions in comparison to other prepared zeolites with different SiO2/Al2O3 ratios. In addition, the ZSM-5(5.4) catalyst exhibited considerably higher conversions under most conditions. The reaction temperature, pressure, WHSV and H2 flow are key factors for this novel isomerization. The obtained results may have a great prospective in useful applications for humankind. In addition, the mechanism of the n-pentane, n-hexane and light naphtha isomerizations over the ZSM-5 zeolites was considered by density functional theory (DFT), using the cluster modeling approach.