Aromatic aldehydes underwent cross-aldol condensation with ketones in the presence of activated carbon supported sulfuric acid (acsa) under solvent-free conditions to afford 16 corresponding α,β-unsaturated aldol products in reaction time of 30～100 min, and the good yields from 65% to 94%. This method provides a simple, fast and clean reaction, using a small quantity of catalyst and a simple workup procedure. The catalyst could be reused. The structures of the products were characterized by IR, ¹H NMR and ¹³C NMR techniques.

Key words: solvent-free, cross-aldol condensation, acsa, ketone, aromatic aldehyde