화학공학소재연구정보센터
Catalysis Letters, Vol.64, No.2-4, 239-246, 2000
Comparative study of the catalytic properties of ferrierite zeolite exchanged with alkaline earth metals in the skeletal isomerization of n-butene
Ferrierite zeolites ion exchanged with alkaline earth cations (Mg2+, Sr2+, Ba2+) were prepared and examined as catalysts for the skeletal isomerization of 1-butene. The samples were characterized by XRD, atomic absorption spectroscopy, ammonia TPD, FT-IR, BET/pore size distribution and pyridine chemisorption. The acidity studies indicated that acid strength increases in the order H+>Mg2+>Sr2+>Ba2+, therefore, the number of weak acid sites follows the opposite trend. At the same time, Bronsted acid sites associated with protons disappear and the number of Lewis acid sites increases with metal content. The presence of bulky cations like Mg2+, Sr2+, Ba2+ leads to a slight reduction of surface area and pore size. Ferrierites containing magnesium exhibit the highest isobutene yield. Lewis acid sites are responsible for improvement in catalyst stability as well as suppression of coke formation.