Preparation and characterization of different phases of aluminum trifluoride

Several phases (alpha, epsilon(z), and gamma) of aluminum fluoride were prepared from precursors such as NH4AlF4, (NH4)(3)AlF6, and beta-AlF3. 3H(2)O using various synthetic strategies. The precursors and the aluminum fluoride phases obtained were characterized by X-ray diffraction (XRD), X-ray fluorescence, scanning electron microscopy (SEM), and infrared spectra (FT-IR), The structural evolution of the precursors to the different phases of aluminum fluoride during thermal treatment was studied by dynamic XRD experiments, differential scanning calorimetry (DSC), and thermogravimetric analysis (TGA), alpha- and gamma-AlF3 phases were obtained with high BET surface areas (>120 and 30 m(2)/g, respectively). These aluminum fluorides with high BET areas are of potential interest as supports or catalysts in hydrodechlorination and fluorination reactions.