The liquid-phase hydrogenation of methylacetoacetate using nickel-exchanged Y zeolite catalysts: Part I. Structure sensitivity

Abstract

The liquid-phase hydrogenation of methylacetoacetate (MAA) over NiNaY and NiKY zeolites to a racemic methyl 3-hydroxybutyrate (MHB) product has been studied in a stirred reactor under a constant hydrogen purge. The variation of MHB formation with time was monitored and reaction rates accurate to ±2% are reported. The effects of variations in the supported nickel metal particle sizes (in the range 16–75 nm) on the hydrogenation activity were examined by altering either the degree of nickel exchange or the temperature of reduction. It is shown that the hydrogenation of MAA at 343 K is structure-sensitive and a correlation between reaction sensitivity and particle size is presented. Data on the reaction over Ni/Si0 2 catalysts are also provided for comparison purposes. Both the zeolite and silica-based catalysts were reusable and could be stored in the reaction solvent for extended periods of time without an appreciable loss of activity.