Pore structure of aluminas derived from the alkyl derivatives of boehmite

The alkyl derivatives of boehmite (alkoxyalumoxanes; AlO(OH)1−x (OR) x ) were synthesized by the reaction of aluminum triisopropoxide in straight-chain primary alcohols at 300 °C for 2 h in an autoclave. In the present work, pore structures of aluminas obtained by calcination of the alkyl derivatives of boehmite were examined. The alumina obtained from the ethyl derivative of boehmite had a broad pore-size distribution, while the pore-size of the alumina obtained from the dodecyl derivative of boehmite distributed in a narrow range in the mesopore region. The mode pore diameter of the latter alumina increased with the increase in calcination temperature (as-syn., 39 Å; 600 °C, 54 Å; 800 °C, 58 Å; 1000 °C, 68 Å), but narrow pore-size distribution was maintained even after calcination at high temperatures.