A growing environmental concern is leading the chemical industry to develop environmentally benign products and processes. alpha,beta-Unsaturated carbonyl compounds are important intermediates, however, their synthesis requires several steps and produces toxic wastes. The catalytic behavior of a Mg,Al-mixed oxide, derived from thermal decomposition of a hydrotalcite and an X zeolite exchanged with cesium and impregnated with cesium species was studied using the aldol condensation reaction between glyceraldehyde acetonide and acetone producing the corresponding alpha,beta-unsaturated carbonyl compound. These catalysts were active for the studied reaction. The product distribution has shown that besides the principle product, other compounds obtained from different aldol reactions were observed. The rehydration of the Mg,Al-mixed oxide generated a catalyst that was selective to the condensation product of glyceraldehyde acetonide and acetone. The decrease of reaction temperature favored the formation of the main product over the Mg,Al-mixed oxide sample. (c) 2005 Elsevier B.V. All rights reserved.