Synthesis and Catalytic Performance of Large Zeolite Y Crystals

1. Introduction Zeolites have gained an irreplaceable role as catalysts in the refining industry. With a production capacity of 625·10 6 t in 2004, the fluid catalytic cracking process (FCC) represents the second most important heterogeneously catalyzed process [1]. As an active component, the catalyst of this process contains zeolite H-Y. Since a high-molecular feed is used, a detailed knowledge of the diffusion behavior of the feed molecules within the pores of zeolite Y is of interest. For several types of diffusion measurements, it is favorable or even essential to apply zeolite crystals with several microns in size. However, until now, only small crystals of high-silica zeolite Y were accessible. The first synthesis of high-silica zeolite Y with crystals of ca. 3 µm has been reported by Delprato et al. [2] and was refined by Karim et al. [3]. Here, we present further efforts in the synthesis of larger crystals of zeolite Y. As a tool to detect different diffusion behavior in small and large crystals [4, 5], the cracking of 1,3,5-triisopropylbenzene over acidic forms of the prepared Y-type zeolites was investigated.