Catalytic condensation of aromatic aldehydes with acetone on activated Mg-Al mixed oxides

Abstract The factors affecting the aldol condensation of some model aromatic aldehydes (benzaldehyde, the three isomers of F-benzaldehyde and 2-naphthaldeyde) with acetone have been investigated using heterogeneous catalysts obtained by the calcination of hydrotalcite-type (HT) precursors at 773 K for 8 h, followed by rehydration at room temperature for 7 h under a flow of N 2 saturated with water vapour. At 273 K the main product was the β-hydroxy-ketone, while at 318 K it mainly dehydrated to the corresponding trans -arylideneacetone, with small amounts ( cis -arylideneacetone, 1,3-diarylideneacetone and 4-hydroxy-4-methyl-2-pentanone. High reaction times favoured the formation of trans -…