Indexed by:期刊论文
Date of Publication:2012-11-01
Journal:MICROPOROUS AND MESOPOROUS MATERIALS
Included Journals:SCIE、EI、Scopus
Volume:162
Page Number:105-114
ISSN No.:1387-1811
Key Words:Titanium silicalite-1; Synthesis condition; Seed; Purification method; Epoxidation of propylene
Abstract:Titanium silicalite-1 with small crystal size (small-crystal TS-1) was synthesized in a TPABr-ethylamine hydrothermal system by using the mother liquor of nano-sized TS-1 as seeds. The synthesis conditions were systematically studied, including the purification methods of the small-crystal TS-1. Si/Ti molar ratio in TS-1, amount of the added seed and the crystallization period. The as-synthesized TS-1 was characterized by X-ray powder diffraction (XRD), Fourier-transform infrared (FT-IR). Ultraviolet-visible diffuse reflectance (UV-vis), Ultraviolet Raman spectroscopy (UV-Raman), nitrogen sorption, elemental analysis, atomic force microscope (AFM) and scanning electron microscopy (SEM). The size of the TS-1 crystals formed (about 600 nm x 400 nm x 250 nm) was not significantly affected by the synthesis conditions except for the amount of added seed. The catalytic performance of the synthesized small-crystal TS-1 for the epoxidation of propylene was evaluated. The conversion of hydrogen peroxide, the selectivity of propylene oxide and the utilization of hydrogen peroxide reached 92.2%, 98.0% and 97.0%, respectively, when the mother liquor of small-crystal TS-1 was purified three times by precipitation, the Si/Ti molar ratio was 50, the seed/SiO2 weight ratio was 0.06 and the crystallization time was 48 h. (C) 2012 Elsevier Inc. All rights reserved.