Synthesis of dimethyl acetal of ketones: design of solid acid catalysts for one-pot acetalization reaction

The synthesis of dimethyl acetals of carbonyl compounds such as cyclohexatione, acetophenone, and benzophenone has successfully been carried out by the reaction between ketones and methanol using different solid acid catalysts. The strong influence of the textural properties of the catalysts such as acid amount and adsorption properties (surface area and pore volume) determine the catalytic activity. The molecular size of the reactants and products determine the acetalization ability of a particular ketone. The hydrophobicity of the various rare earth exchanged Mg-Y zeolites, K-10 montmorillonite clay, and cerium exchanged montmorillonite (which shows maximum activity) is more determinant than the number of active sites present on the catalyst. The optimum number of acidic sites as well as dehydrating ability of Cc(3+)-montmorillonite and K-10 montmorillonite clays and various rare earth exchanged Mg-Y zeolites seem to work well in shifting the equilibrium to the product side. (c) 2004 Elsevier Inc. All rights reserved.