The consecutive condensation, dehydration and hydrogenation of acetone were studied in a lab scale trickle bed reactor. Amberlyst(R) CH28, a commercial palladium impregnated cation exchange resin catalyst was used. Acetone conversions varying from 25 to 50% were obtained at operating temperatures from 130 to 150 degreesC and acetone LHSVs from 4 to 16h(-1). The methyl isobutyl ketone (MIBK) selectivities varied between 70 and 90%. The results indicated that the condensation-dehydration rate-limiting step severely decreases with increasing conversion, causing a serious decrease in catalyst productivity at higher liquid residence times. This is attributed to the rate-inhibiting effect of the water-formed in the dehydration reaction-on the catalyst. The mesityl oxide (MSO) content in the reaction mixture was below 0.1% (mass) except at temperatures above 140 degreesC and at high condensation-dehydration rates. It was further shown that an acetone saturated catalyst bed has an 18% smaller volume than an equivalent water saturated bed. (C) 2004 Elsevier B.V. All rights reserved.