Abstract: The physicochemical properties of four zeolites with various pore structure and mesopore volume were characterized by XRD, BET and NH3-TPD. The hydrocracking performances of four catalysts containing zeolite Beta, ZSM-5, zeolite Y1 and Y2 respectively were investigated using n-decane as model feed. The results showed that the pore structure and acidity of zeolite strongly influenced the activity, isomerization selectivity, product distributions and reaction mechanism of n-decane hydrocracking. Zeolite Beta showed the highest activity and isomerization selectivity, followed by zeolite Y, and ZSM-5 was the least. Within the two types of zeolite Y, zeolite Y2 with larger mesopore volume showed higher isomerization selectivity. The hydrocracking of n-decane over zeolite Beta and zeolite Y catalysts was mainly β-scission of tri-branched carbonium ions, thus their products contained more branched hydrocarbons. In contrast, over ZSM-5 catalyst, most products were normal alkanes due to the β-scission of mono-branched carbonium ions.

Key words: hydrocracking, n-decane, zeolite, pore structure, acidity