EFFECT OF HALOGEN ANION ON HEXANE AROMATIZATION ACTIVITY OF PT KL CATALYSTS/

Potassium salts were added to the catalyst prepared by ion exchange of KL with [Pt(NH3)4]Cl2 and the effect of their counter anion on the ac tivity and selectivity for hexane aromatization was studied. The catal yst to which KF was added showed the highest activity and selectivity for benzene formation; methylcyclopentane and hydroisomerization produ cts were negligible. Although the catalyst with KCl added also exhibit ed excellent performance, the catalysts with KBr or KI added gave rise to low hexane conversion and benzene yield. Infrared spectra of adsor bed CO revealed that the presence of the low frequency C-O stretching band is closely related to catalytic performance of the Pt/KL series c atalysts. The electron-rich Pt site formed through the interaction wit h KF or KCl may be responsible for the high activity and selectivity f or hexane aromatization.