Formation of high octane gasoline by zeolite cracking catalysts

A survey is presented of the effects of operational changes on gasoline octane number. Following the survey, data are presented to show that the new Octacat catalyst developed by Davison Research catalytically enhances gasoline octanes under any given set of operational conditions by increasng the concentration of aromatics and olefins in this fraction. Higher yields of gasoline and light olefins (mainly butenes) and lower yields of coke are also realized. These shifts are believed to be a result of a change in Lewis/Bronsted acid site ratio and acid site density, which acts to reduce catalyst H/sub 2/ transfer rates and overall cracking rates. Work is continuing to better define the mechanism of these selectivity changes.