Synthesis and characterization of the microporous titanosilicates ETS-4 and ETS-10

In the last years the interest in new zeolitic structures has increased. Some of these materials possess improved catalytic and adsorptive properties in comparison with the classical aluminosilicates. Among these materials are the AlPOs which opened new roads in the study of zeotypes. Subsequently, the study of titanium- and silicon-based molecular sieves was deepened. Among the numerous synthesized structures ETS-10 is a totally synthetic one while ETS-4 is the synthetic counterpart of the mineral zorite. In this paper a complete study is devoted to the ETS-10 and ETS-4 crystallization fields as a function of the quantities of Na2O and TiO2 in the initial gel. The influence of the initial pH on the two phases was also studied. The crystallization curves as a function of time for ETS-10 and ETS-4 with different initial Na and Ti contents were determined and analyzed. The SEM pictures allowed one to determine the morphology of the two ETS phases. Their compositions were determined by chemical analysis, and local structural characteristics were derived from NMR analysis. (C) 2002 Elsevier Science Inc. All rights reserved.