Synthesis and characterization of titanosilicate materials

Recent developments in the use of titanosilicate materials as redox catalysts and ion exchangers have indicated that these materials contain important Ti-O-Si linkages; variations in the coordination number of the Ti(IV) ion influences the unique acid-base properties of these materials. A clear understanding of the molecular assembly pathway and reaction conditions that control the formation of these materials is necessary for the development and optimization of new titanosilicate materials. A systematic investigation into the synthesis of titanosilicate materials using sol-gel, solid-state and hydrothermal methods was conducted to understand the parameters that influence the formation of these materials. These syntheses were monitored by systematic analysis of the intermediate phases and materials formed using powder X-ray diffraction and 29Si MAS NMR spectroscopy. These investigations have led to the discovery of a novel method of synthesizing catalytically active titanosilicate materials. This method provides an avenue for homogeneous incorporation of titanium into the silicate framework without the formation of extra-framework titanium sites such as TiO₂ or alkali titanate phases, and with a Ti:Si ratio higher than is obtainable by other methods. The synthesis and 29Si MAS NMR spectra for a number of titanosilicate materials, such as, the catalysts ETS-4, ETS-10, ETS-14, TS-1, JDF-L1, the ion exchange materials HK₃Ti₄O₄ (SiO ₄)₃· 4H₂O, Na₂Ti₂O ₃SiO₄· 2H₂O and the synthetic analogues of the titanosilicate minerals natisite, titanite, narsarsukite, nenadkevichite, penkvilksite and fresnoite are reported.