High stability zone zeolites in octane catalysts - New products from Union Carbide Corporation and Katalistiks International, Inc

The ability of zeolite cracking catalysts to moderate the research octane number and, to lesser extent, the motor octane number of FCC gasoline has been known for well over ten years. Considerable effort has been made during this period to understand the mechanism of the catalytic reactions involved. This paper discusses the following: 1) Silicon Enriched Framework Y Zeolites (SEF-Y) when compared with aluminum deficient faujasites exhibit both increased thermal and hydrothermal stability. Collapse temperatures as measured by DTA are at least 200/sup 0/C higher for the enriched framework materials. 2) The increased stability afforded by the Framework Silicon Enrichment process is believed to be due to the drastically reduced number of defects compared with dealuminated structures. 3) High Stability Zone Zeolite catalysts containing SEF-Y exhibit less non-selective cracking resulting in both improved gasoline and coke selectivity while maintaining octane levels at least as high as dealuminated species. 4) The improved selectivity is believed due to the much reduced silica/alumina and alumina ''debris'' present in the SEF-Y compared with dealuminated structures.