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

Ti-containing MCM-41 mesoporous materials with regular 35 Angstrom por e diameters have been obtained by direct synthesis. The OH/SiO2 ratio and alkali metal cation content are important variables to prepare goo d 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 p ositions and no extraframework TiO2 was detected. The materials prepar ed 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 w hen using H2O2 as oxidant. When using tertbutyl hydroperoxide the acti vity of Ti-MCM-41 is closer to that of Ti-Beta and much higher than fo r 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.