Acid-base Properties of Silica-aluminas - Use of 1-butanol Dehydration As a Test Reaction

1-Butanol dehydration was performed as a test reaction for acid-base characterization on a series of silica-aluminas covering the whole composition range (0-100% Al2O3). Alumina-rich samples (80-100% Al2O3) dehydrate 1-butanol to 1-butene and dibutylether. Silica-aluminas with 5-70% Al2O3 dehydrate 1-butanol to 1-butene which directly isomerizes to cis- and trans-2-butenes. The acid-base properties were also investigated by ammonia and carbon dioxide TPD and FT-IR spectroscopy of adsorbed pyridine, in parallel with another test reaction, 4-methyl-2-pentanol dehydration. The acidity-basicity profiles are discussed as a function of alumina content (nature, strength and amount of sites). A very good correlation between the results of test reactions and acid-base characterization methods is observed. Our study confirms previous results obtained on another series of silica-aluminas, but, in addition, the usefulness of the rapid and simple TPD method and 1-butanol dehydration as a test reaction is revealed.