Reaction chemistry related to FCC gasoline quality

The cracking of n-hexane on different zeolites has been studied. Catalytic experiments at 1 atm were carried out in a continuous fixed bed reactor. By means of measuring the initial rates for the cracking of n-hexane over two series zeolites, Y and Beta, a correlation between the Broensted acid sites and the initial rates has been found. The initiation steps of n-hexane cracking occur on the Broensted acid sites, Lewis acid sites being inactive for these steps. Acid site density and acid site strength of zeolite determine the activity of n-hexane cracking. The role of acid site density predominates in most cases, however, the acid site strength also plays an important role in some instances. Similar intrinsic catalytic activities of different zeolites have been found. The effects of zeolite structure, acid site density, and reaction temperature on the mechanism of n-hexane cracking and "cracking chain length" have also been studied.