Boehmite, magnesium-aluminum and chromium-aluminum hydroxides prepared from the corresponding chloride solutions of aluminum, magnesium and chromium, respectively, using ammonia solution at pH similar to 9. The precipitated hydroxides subjected to thermal treatment at 450 degrees C to produce gamma-alumina and magnesium-aluminum mixed oxide and at 600 degrees C to produce chromium-aluminum mixed oxide materials. The materials characterized using Fourier transformer infrared spectroscopy, X-ray diffraction pattern, differential scanning calorimetry and BET surface analyses. The catalytic activity of these materials toward cyclohexane dehydrogenation reaction was performed in a pulse micro-catalytic reactor operated under atmospheric pressure at reaction temperature ranged from 250 to 550 degrees C. The results indicated that, chromium-aluminum oxide material which possess crystallite size, 27.0 nm and surface area 89.0 m(2)/g, is the most active material toward benzene formation (23.7%) at reaction temperature 500 degrees C. Meanwhile, magnesium-aluminum oxide is the most selective one toward benzene formation (crystallite size, 3.0 nm and surface area, 209.7 m(2)/g) as compared with the other prepared materials. (c) 2007 Elsevier B.V. All rights reserved.