(446a) Organotemplate-Free Beta Zeolites: From Zeolite Synthesis to Hierarchical Structure Creation

Zeolite beta is a large-pore, crystalline material that features an intergrowth of two or more polymorphs comprising a three-dimensional, 12-membered ring channel system with great potential in refinery, petrochemical, and chemical applications. During the past decade, the seed-directed organotemplate-free strategy has been successfully developed for the synthesis of beta zeolites. This presentation will focus on extending the organotemplate-free strategy to the synthesis of hierarchical beta zeolites without using organic structure-directing agents (OSDA), pore-directing agents (PDA), or mesoporous templates, which is achieved by hydrothermal desilication that is amenable for beta crystallization. Organotemplate-free creation of hierarchical structures will be demonstrated for both OSDA-free and conventional beta zeolites as parent zeolites. The resulting hierarchical beta zeolites have higher pore volumes and exhibit improved catalytic performance for the conversion of bulky molecules. They show promise for a variety of applications in which the presence of large mesopores are required to reduce diffusion limitation and coking formation.