Jointly published by React.Kinet.Catal.Lett. Akadémiai Kiadó, Budapest Vol. 80, No. 2, 365-373 and Kluwer Academic Publishers, Dordrecht (2003) 0133-1736/2003/US$ 20.00. © Akadémiai Kiadó, Budapest. All rights reserved. RKCL4358 EFFECT OF PRETREATMENT OF THE CATALYST AND CATALYST-MODIFIER SYSTEM IN THE ENANTIOSELECTIVE HYDROGENATION OF ISOPHORONE Éva Sípos and Antal Tungler* Department of Chemical Technology, Budapest University of Technology and Economics, H-1521 Budapest, Hungary Received June 20, 2003 In revised form August 19, 2003 Accepted August 21, 2003 Abstract The effects of the preliminary hydrogenation, the variation of the addition sequence of the components and that of the sonochemical treatment were investigated in enantioselective hydrogenation of isophorone over Pd black catalyst in the presence of chiral modifiers. Keywords: Isophorone, asymmetric catalysis, hydrogenation, palladium INTRODUCTION The hydrogenation of β-keto esters with tartaric acid modified Ni [1] and the hydrogenation of α-keto esters with cinchona alkaloids modified Pt [2] are the best-known heterogeneous chiral catalytic reactions with enantioselectivities up to 98% . In the last two decades the scope of chiral modifiers [3-9] and prochiral substrates [8-20] has broadened. In some of these reactions Pd appeared too as a catalytically active metal. According to several reports the Pd dispersion, the nature and texture of the support as well as the catalyst preparation and pre-treatment can exert significant effects on the enantioselectivity of the Pd catalysts [11]. __________________________________________ *Corresponding author. Tel.: (+36-1) 4631203; fax: (+36-1) 4631913; e-mail:atungler@mail.bme.hu