(569cn) Non-Destructive Routes to Increased Active Site Accessibility in Zeolite Y

Faujasite zeolites are widely used catalysts for catalytic cracking and reforming reactions. Sodalite cages contain 60% of the active sites in a faujasite zeolite, but are inaccessible to the majority of reagents due to narrow pore openings. Recently some studies have shown a new method to open these sodalite cages which enlarges the opening and makes the cage accessible to larger molecules, but the methods used also cause a loss of crystallinity, and a decrease of total acid sites of the catalyst. New and robust methods of opening the sodalite cages to make those active sites accessible to reagents non-destructively are crucial for improved conversion and selectivity. In this presentation, we will show how ammonium fluoride etching of zeolite Y makes the previously inaccessible sodalite cages accessible to larger molecules. We will assess how this process affects the crystallinity of the prepared sample by X-ray diffraction, the quantity of acid sites by ¹H MAS NMR, and the catalyst framework by ²⁷Al MAS NMR and ²⁹Si MAS NMR. By comparing the prepared sample to a standard Zeolite Y, we will address how the modification affects both the acid site distribution and the overall zeolite structure.