“Base-acid mechanism for the citral/acetone reaction on MgyAlOxOxides

V.K. DÍEZ; J.I. DI COSIMO; C.R. APESTEGUÍA

Ancient Harvor, Genova, (Italy).

Congreso; 6th World Congress on Catalysis by Acids and Bases (ABC-6); 2009

The liquid-phase aldol condensation of citral with acetone (DMK) is catalyzed by diluted bases and forms selectively pseudoionones (PS), but the process entails concerns related to toxicity, corrosion, and disposal of spent base materials. New industrial strategies for PS synthesis demand then the replacement of liquid bases by solid catalysts. The citral/DMK reaction has been studied on Mg-Al mixed oxides (MgyAlOx), but knowledge regarding the role played by the MgyAlOx chemical composition to fulfill the requirements of acid/base site density and strength for promoting the selective PS formation at high rates, is lacking. The optimum MgyAlOx composition should improve the citral/DMK cross-aldol condensation rate at expenses of the DMK self condensation reaction. Here, we have carried out a detailed study of the citral/DMK reaction on MgO, Al2O3, and MgyAlOx with Mg/Al molar ratios of 0.11-3. The structural, textural and acid/base properties of the samples were determined by using a variety of experimental techniques and then correlated with the catalyst performance for citral/DMK reaction.