CHARACTERIZATION OF ISOMORPHOUSLY SUBSTITUTED ZSM-23 AND CATALYTIC PROPERTIES IN N-BUTENE ISOMERIZATION

Pure and well crystallized Al-and Fe-ZSM-23 were synthesized by a hydr othermal method. The products were characterized by XRD, SEM, n-hexane adsorption, chemical analysis, TPD of NH3 and IR thermodesorption of pyridine. The characterization results reveal that the substitution of Al with Fe leads to a considerable decrease in the strength of the Br onsted acid sites. n-Butene isomerization over Al- and Fe-ZSM-23 has b een tested. It is shown that the lower Bronsted acidity of Fe-ZSM-23 c ompared with Al-ZSM-23 is reflected in a lower activity and higher sel ectivity in n-butene isomerization.