AL(2)O(3) materials were obtained by calcination of boehmite samples of varying crystallinity at 600 degrees C. Boehmites were obtained from Al-2(SO4)(3)(.)18H(2)O or AlCl3 under hydrothermal conditions and autogenous pressure at different synthesis temperatures (T-s = 40, 140 and 180 degrees C), and were studied by XRD, IR(Py), DTA and TGA. It was found that Ts is closely related to the physicochemical properties of boehmites, and thus of gamma-Al2O3. Increased amounts of sulfur were detected in gamma-Al2O3 for lower T, using aluminum sulfate. Less-crystalline boehmites were obtained when using aluminum sulfate compared to aluminum chloride. While only Lewis acidity was found in gamma-Al2O3 materials produced from aluminum chloride, aluminum sulfate produced both Lewis and Bronsted acidity, with the Bronsted/Lewis ratio depending on the crystallite size. (c) 2005 Elsevier B.V. All rights reserved.