(713b) Vapor-Phase Strategy to Pillaring of Two-Dimensional Zeolite
Two-dimensional (2D) layered zeolites are new expression forms of 3D zeolite frameworks. They can be pillared to form more open porous structures with increased access of reactants that are too big for the micropores of zeolites. The current pillaring procedure, however, requires intercalation of pillar precursors by dispersing 2D zeolite in an alkoxide liquid and then hydrolysis of entrapped alkoxide to form inorganic oxide pillars in an aqueous alkaline solution. Both steps use excess solvents, generate much waste and require for multiple synthesis/separation steps. Here we report a vapor phase pillarization (VPP) process to produce pillared zeolites from 2D layered zeolite structure. The VPP process has ~100% efficiency in alkoxide usage in the intercalation step, requires for less (and even zero) water addition in the hydrolysis step, does not need separation for product recovery, and generates no liquid waste. Furthermore, synthesis of pillared zeolites via the VPP process can be accomplished within a single apparatus in one-time operation. The pillared zeolite prepared by the VPP method preserved zeolitic layer structure as well as acidity, and showed enhancement in catalytic alkylation of mesitylene with benzyl alcohol compared to 2D layered zeolite without pillarization treatment.