The catalytic cracking of n-pentane was performed with HY, modified HY, NiHY, ZSM-5 adn ZSM-11 zeolite catalysts.
HY zeolites were modified to have different Si/Al ratios through dealumination process using $H_4EDTA$, $SiCl_4$ and steam. ZSM-5 catalysts with different Si/Al ratios were also employed.
To characterize these catalysts, amine titration, TPD and XRD experiments were performed. The fraction of strong acid sites was increased as the extent of dealumination was increased.
When the dealumination was greatly progressed by $SiCl_4$($SiO_2$/$Al_2O_3$=312, 455) and steam($SiO_2$/$Al_2O_3$=12.1, 12.4), the HY zeolites showed an increase in acidity but a decrease in total number of acid sites and also a rapid deactivation by coking.
The reaction network of n-pentane cracking was proposed using the initial selectivities. The reaction networks indicated that the disproportionation reaction was main reation in HY zeolite while direct cracking in ZSM-5 catalyst.