One-step methyl isobutyl ketone synthesis from acetone and hydrogen using Amberlyst CH28

The consecutive condensation, dehydration and hydrogenation of acetone were studied in a lab scale trickle bed reactor. Amberlyst^® 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 °C and acetone LHSVs from 4 to 16 h⁻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 °C 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.