One-step synthesis of methyl isobutyl ketone from acetone and hydrogen over Pd/(Nb2O5/SiO2) catalysts

The surface-phase oxides of niobia on silica substrate ((Nb2O5/SiO2), NS(x) ) were prepared and characterized. Such oxides were used as supports for pa lladium catalysts. The one-step synthesis of methyl isobutyl ketone (MIBK) from acetone and hydrogen in liquid phase was also investigated over Pd/NS( x) catalysts, Experimental results indicate that these catalysts were effec tive for the formation of MIBK; since little of the parallel by-product of isopropanol (IPA) was formed, these catalysts reached selectivities of 88-9 2% MIBK and 2-3% IPA at 30-35% conversion. The reactivity of Pd/NS(x) decli ned obviously with an increase of water content that accumulated in a semi- batch reaction system. The water could be partially expelled and the deacti vation of catalysts could be improved by using a fixed bed continuous Row r eaction system. (C) 2001 Elsevier Science B.V. All rights reserved.