REMOVAL OF TEMPLATE FROM Pd/FER AND ITS CATALYTIC PERFORMANCE FOR SKELETON ISOMERIZATION OF n-BUTENE

Abstract

Abstract: HFER-CHA was prepared and modified by palladium. The template was removed by calcination in flowing air at different temperatures. The effect of palladium modification on the removal of the template was investigated, and the catalytic performance for the skeletal isomerization of n-butene was studied, and the catalyst was characterized by XRF, XRD and NH₃-TPD, etc. The results showed that the calcination temperature affected the removal efficiency and properties of the zeolite template, and palladium modification significantly reduced the removal temperature of the template in the HFER. The template could be completely removed by calcining Pd/HFER-CHA in air at 350 ℃ for 4 h. The removal of the template increases the specific surface area and pore volume of zeolites. As the calcination temperature increases, the acidity of zeoilites increases, and the catalyst activity rises. The increase in Lewis-acid is the main reason for the side reactions such as polymerization and cracking of n-butene. After the Pd/HFER-350 was continuously operated for 720 h under conditions of 350 ℃, 0.1 MPa, and a mass space velocity of 2.0 h^-1 for n-butene,the average conversion rate of n-butene was greater than 40%, and the selectivity of isobutene was greater than 90%.

Key words: FER zeolite, palladium, templates removal, n-butene, skeletal isomerization

References

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