Direct Synthesis of Methyl Isobutyl Ketone by Reductive Aldol Condensation. III. Kinetics

Abstract

Abstract The kinetics of the direct catalytic conversion of acetone and hydrogen into methyl isobutyl ketone (MIBK) were investigated in the liquid phase using palladium–zirconium phosphate as a catalyst. Kinetic studies on the conversion of acetone into mesityl oxide (4-methyl-3-pentene-2-one) and its hydrogenation were separately carried out using the same catalyst. It was found that the direct reaction proceeded via a sequence of processes: mesityl oxide was first formed by condensation of acetone on acid sites of the catalyst and MIBK was then produced by hydrogenation of the mesityl oxide on palladium metal in the catalyst. Moreover, the experimental results were well interpreted by assuming that the condensation of acetone was controlled by a surface reaction between the acetone molecules adsorbed on the catalyst surface and that the rate of hydrogenation of mesityl oxide was determined by a surface reaction between dissociated hydrogen atoms and adsorbed mesityl oxide molecules.