On the structural, acidic and catalytic properties of zeolite SUZ-4

Highly crystalline SUZ-4 zeolite was synthesized and its acidic and catalyt ic properties were investigated using FTIR spectroscopy and n-hexane conver sion. Based on the analysis of the published crystallographic data, it is c oncluded that SUZ-4 zeolite has a three-dimensional pore system that includ es ten-membered ring channels parallel to unit cell c-axis which are inters ected by two arrays of eight-membered ring channels running in the plane [0 01]. Experimental results reported here support this conclusion. About 45% of acid sites (bridging hydroxyls) are located in the large channels of SUZ -4 zeolite, while the remaining sites occupy positions in nonplanar double eight-membered rings. The bridging hydroxyls in SUZ-4 zeolite are more acce ssible for guest molecules (n-hexane and isobutane) than those in ferrierit e. Both zeolites show similar strength of acid sites and have similar proto lytic cracking activity. The hydrogen transfer activity of ferrierite is ob served to be higher than that of the SUZ-4 zeolite. These results indicate that SUZ-4 zeolite has potential as a catalyst and may display unusual shap e selective properties in comparison with other zeolites.