Síntese de silicogermanatos zeolíticos empregando compostos amônio quaternários como direcionadores de estrutura

Abstract

Zeolites are one class of molecular sieves with cristalline structure and may have different compositions for the replacement of Si by another element. In the case of silicogermanates, Si atoms were replaced by Ge in the structural network and are denominated zeotypes. In this study, results were obtained of the silicogermanate zeolites synthesis using different strategies. One of these is the use of organic compounds that can act as structure direct agent. In the present study, it was used three different compounds with C/N+ = 6, 15 and 13; being two of these novel compounds for use in zeolite synthesis. The compounds were evaluated for resistance to ion exchange and in zeolites synthesis using different compositions that primarily include the use of silicon and germanium and boron in some tests. Some syntheses were carried out in basic medium and others in the hydrofluoric medium. For characterization of organic compounds were used the Nuclear Magnetic Resonance techniques (NMR), Infrared spectroscopy (IR) and chemical analysis for CHN. Some procedures were also performed with the combined use of an organic and an inorganic driver, in this case LiOH. The zeolites synthesis products were characterized by Diffraction X-ray (XRD), Thermogravimetry analysis (TGA), chemical analysis by CHN, chemical analysis by Inductively plasma atomic emission spectroscopy (ICP-AES), Infrared Spectroscopy (IR) and Scanning electron microscope (SEM) and Energy Dispersive Spectroscopy (EDS). With the use of the N,N,N-Trimethyl-2-adamantammonium iodide - (3SDA(I)1), known in zeolite synthesis, it was possible to synthesize a silicogermanate with STT type structure.