(445e) Acid/Base Investigations of Thermally Decomposed Acetylacetonates Supported on Nanocrystalline Mgo

The surface of nanocrystalline MgO was modified by supporting various acetylacetonates (AcAcs), such as Na, Cu, Fe, and Al, in order to determine their effect on surface acidity and basicity. These catalysts were investigated using adsorption microcalorimetry of CO₂ and NH₃ in order to probe the effect of the surface species on surface basicity and acidity, respectively. For each of the AcAcs supported on the surface, a decrease in the total CO₂ adsorption was observed, indicating that the supported species bond through surface base sites present on the surface of nanocrystalline MgO. The NH₃ uptake was reduced when Na and Cu AcAcs were supported; however, the uptake was not reduced when AcAcs of the trivalent cations were used. The catalytic activities for various reactions of differing acid/base requirements were used to probe the surface. For example, the dehydrogenation of 2-propanol over FeAcAc supported on nanocrystalline MgO gave roughly a two-order of magnitude enhancement in the rate of acetone production compared to unmodified nanocrystalline MgO. All other supported AcAc catalysts showed modest improvements in selectivity toward acetone with no significant enhancement in decomposition rates. The effect of treatment temperature on catalytic activity and type of surface species will be discussed.