An example of mesostructured zeolitic material: UL-TS-1

A new approach for the synthesis of titanium containing mesostructured zeolitic materials, UL-TS-1, that involves the use of surfactant containing amorphous mesoporous titania-silica as precursor phase is reported. UL-TS-1 was synthesized in the solid state by heating TPAOH-impregnated precursor materials at 120 degreesC for several days. Various techniques including XRD, N-2 adsorption, UV-visible, FTIR, TEM and Si-29 MAS NMR were used to monitor the physico-chemical properties of these materials as a function of crystallization time. The XRD diffractograms show broad peaks, which match those of ZSM-5 and grow in intensity as the crystallization time is increased. The increase in the percentage of crystallinity is also correlated with the corresponding variations in micropore and mesopore volumes, BET and BJH surface areas. The results indicate that the mesopore walls consist of zeolite nanocrystals. Depending on crystallization time, a range of materials from totally amorphous up to 80% crystalline is observed, while some of mesopores are preserved. The FTIR and UV-visible results also show that all titanium ions are essentially incorporated into the UL-TS-1 framework. (C) 2001 Elsevier Science B.V. All rights reserved.