SYNTHESIS, CHARACTERIZATION, AND CATALYTIC ACTIVITY OF TI-MCM-41 STRUCTURES

摘要

Ti-containing MCM-41 mesoporous materials with regular 35 Angstrom pore diameters have been obtained by direct synthesis. The OH/SiO2 ratio and alkali metal cation content are important variables to prepare good materials. By means of IR spectroscopy, XRD, N-2 and Ar adsorption, thermal analysis, DR-SW and EXAFS-XANES techniques, it has been shown that samples with MCM-41 structure were prepared, Ti is in framework positions and no extraframework TiO2 was detected. The materials prepared are selective catalysts for oxidation of different types of olefins. The intrinsic activity of Ti-MCM-41 is lower than Ti-Beta and TS-1 when using H2O2 as oxidant. When using tertbutyl hydroperoxide the activity of Ti-MCM-41 is closer to that of Ti-Beta and much higher than for TS-1. Ti-MCM-41 has a clear advantage over the other Ti zeolites in the oxidation of large organic molecules of interest for production of fine chemicals. (C) 1995 Academic Press, Inc. [References: 59]