The self-condensation of acetophenone (ACP) to alpha,beta-unsaturated ketone in the liquid phase has been studied using sulfated zirconia (SZ), sulfated titania (ST) and H-beta zeolite as catalysts in the temperature range of 403-433 K. It is found that SZ and H-beta exhibit similar activity (rate of ACP conversion), which is higher than that of ST. From the TPD of NH3 it is seen that both SZ and H-beta are highly acidic and possess strong acid sites, as seen from NH3 desorption in the temperature range of 513-873 K, which are responsible for the reaction. The conversion of ACP increases with reaction time, the catalyst concentration and reaction temperature. The SZ is recycled two times to show that there is only a marginal decrease in activity on recycled catalyst with no loss in the selectivity for dypnone. (C) 2002 Elsevier Science B.V. All rights reserved.