Preparation of titanium-containing zeolites with MEL structure from B-ZSM-11 and their characterization

Titanium-containing MEL zeolites (Ti-ZSM-11) are prepared by gas-solid reac tions between TiCl4 vapor and B-ZSM-11 precursors. XRD, FTIR, UV-Vis, B-11 and Si-29 MAS NMR techniques are used to characterize these materials. The results show that Ti atoms are incorporated into the silanol nests that wer e previously occupied by B atoms. The precursor deboronated by acid reflux possesses a large amount silanol nests and so can obtain a high concentrati on of titanium in the framework, compared to the directly calcinated precur sors. Ti-ZSM-11 zeolites are used to catalyze the epoxidation of propylene with dilute hydrogen peroxide. The results show that the catalytic activiti es are related to the physicochemical properties of these materials. (C) 20 00 Elsevier Science B.V. All rights reserved.