The amorphous and crystalline mixed 25,50 and 75 wt.%Al2O3-ZrO2 composites were prepared by means of sol-gel method using aluminum iso-propoxide and zirconyl nitrate precursors. Physicochemical properties were determined using XRD, BET, NH3-TPD, TGA, SEM, and Ft-IR spectroscopy. Catalytic activity and selectivity were investigated for the dehydration of 2-octanol and 1,2-dipheny1-2-propanol (DPP). Al75Zr25 composite is more selective than other forms for the conversion of 2-octanol. The selectivity of DPP for 1-alkene formation was increased over Al25Zr75 catalyst. The crystalline 50 wt.% catalyst dehydrated tertiary alcohol (DPP) selectively in the presence of 2-octanol. The amorphous 50 wt.% catalyst dehydrated DPP predominately to 1-alkene isomer. The crystalline catalyst favored the formation of E-2-alkene. (C) 2011 Elsevier B.V. All rights reserved.