Refining of crude oil consists of multiple steps, including a hydrocracking process, which converts higher boiling components of the crude mixture to lower boiling small molecules. Zeolites are traditionally used as catalysts in the hydrocracking process due to their high acidity and excellent catalytic activity. These zeolites have pores or channels within the micropore range (less than 2 nm in diameter).  The small size of these zeolite pores can inhibit free diffusion of substrates and products of the catalytic reaction within the materials and can exclude large molecules from the catalytic processes. As a result, a fraction of crude oil does not undergo hydrocracking with traditional zeolite catalysts and is rejected as vacuum residue. Introduction of mesopores (pores 2-50 nm in diameter) in the zeolite structure while still maintaining catalytic activity is necessary for hydrocracking the higher molecular weight components of the crude oil.<br/>Mesoporosity can be introduced in zeolites using hard templates during zeolite synthesis. Hard templates are materials that are not dissolved in the zeolite precursor mixture but instead provide crystallization surfaces for the growing zeolite particles, limiting the size of the zeolite crystals and occupying space between the zeolite agglomerates. Upon calcination, the hard template materials are removed, giving rise to mesopore-sized voids. Alternatively, hard templates can be encased within the zeolite crystals, yielding intramolecular mesopores. We demonstrate that a new class of inexpensive hard templates, cellulose nanocrystals and nanofibers, can be used in the synthesis of mesoporous zeolites to produce materials with excellent surface area, porositiy profiles, and catalytic activity towards large molecules.<br/>

Synthesis of mesoporous zeolites using nanocellulose as an inexpensive hard template

255th National Meeting (2018)

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