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

A new approach for the synthesis of titanium containing mesostructured zeol itic materials, UL-TS-1, that involves the use of surfactant containing amo rphous mesoporous titania-silica as precursor phase is reported. UL-TS-1 wa s synthesized in the solid state by heating TPAOH-impregnated precursor mat erials 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 monito r the physico-chemical properties of these materials as a function of cryst allization time. The XRD diffractograms show broad peaks, which match those of ZSM-5 and grow in intensity as the crystallization time is increased. T he increase in the percentage of crystallinity is also correlated with the corresponding variations in micropore and mesopore volumes, BET and BJH sur face 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 mesopor es are preserved. The FTIR and UV-visible results also show that all titani um ions are essentially incorporated into the UL-TS-1 framework. (C) 2001 E lsevier Science B.V. All rights reserved.