Influence of the acid-base properties of solid catalysts derived from hydrotalcite-like compounds on the condensation of formaldehyde and acetaldehyde

The vapor-phase aldol condensation of formaldehyde with acetaldehyde was st udied using various oxide mixtures obtained in situ from hydrotalcite-like materials as catalysts. All samples exhibited catalytic activity, but the s electivity to both the aldol condensation and the acrolein formation is gov erned by the balance of acidic and basic properties. The oxides containing Mg and Al or Co and Al showed a high selectivity to aldol condensation (90% at 300 degrees C) as well as to cross-condensation (80% at 300 degrees C). The effects of both the reaction variables (temperature, mole ratio of rea gents) and the catalyst variables (nature of cations, nature of anions) wer e studied. (C) 1999 Elsevier Science B.V. All rights reserved.