TUD-1-Encapsulated HY Zeolite: A New Hierarchical Microporous/Mesoporous Composite with Extraordinary Performance in Benzylation Reactions

A new composite material consisting of amorphous TUD-1 encapsulating crystalline zeolite Y was synthesized. Samples with different HY zeolite loadings (10, 20, 40, and 60wt%) were prepared, and the resulting solid products were characterized with elemental analysis, XRD, N-2 physisorption, (27)AlMAS NMR, IR, pyridine adsorption in combination with FTIR, temperature-programmed desorption of ammonia, HRSEM, and HRTEM. Characterization data confirm the presence of a thin layer of the mesoporous TUD-1 phase with a thickness of 30-100nm surrounding the zeolite crystals. The catalytic performance of the composite was studied in the Friedel-Crafts benzylation of benzene with benzyl alcohol at 353K. The catalytic activity of the HY/TUD-1 composite was higher than that of HY zeolite, whereas the composite showed a much slower rate of deactivation. The improved performance of the composite is related to beneficial changes in the acidity of the HY crystal through chemical interactions with TUD-1.