Stable Bulky Particles Formed by TS-1 Zeolite Nanocrystals in the Presence of H2O2

Bulky particles of TS-1 zeolite (larger than 20 pm) are successfully collected by simple filtration after crystallization of TS-1 zeolite in the presence of H2O2. Bulky TS-1 (B-TS-1) has good stability under both ultrasonic conditions and in recycling of the catalyst. Nitrogen isotherms show that B-TS-1 has a larger mesopore volume (0.55 cm(3) g(-1)) than conventional TS-1 nanocrystals (N-TS-1; less than 300 nm) obtained from high-speed centrifugation (0.28 cm(3) g(-1)). In catalytic hydroxylation of phenol with H2O2, both fresh (25%) and recycled B-TS-1 (24%) show similar high activities to N-TS-1 (28%). B-TS-1 was further characterized by X-ray diffraction, scanning electron microscopy, transmission electron microscopy, UV/Vis spectroscopy, and other techniques. The results suggest that bulky particles of B-TS-1 were formed by strong interactions of the nanocrystals with each other in the synthesis of TS-1 zeolite. Such unique structural features might be responsible for the high stability of the bulky particles, large mesopore volume, and high catalytic activities in phenol hydroxylation, as well as the collection of B-TS-1 from a simple filtration route.