Hydrotalcites as Base Catalysts: Influence of the Chemical Composition and Synthesis Conditions on the Dehydrogenation of Isopropanol

Hydrotalcites with different Al/Al + Mg ratios, and prepared at different pH and different aging temperatures of the gel were used as precursors of Mg-Al mixed oxides, and their textural and physicochemical properties were determined. A complete reaction network for the isopropanol decomposition on these catalysts has been established, and it is shown that the concentration of acetone in the products cannot always be used for a direct estimation of the rate of dehydrogenation. The Al/Al + Mg ratio for which the maximum in activity is obtained depends on the base strength needed for each particular reaction. For dehydrogenation of isopropanol, this is found at Al/Al + Mg ≍ 0.25.