Res. Chem. Intermed.
, Vol. 30, No. 9, pp. 889–901 (2004)
Also available online - www.vsppub.com
Enantio-differentiating hydrogenation of methyl
acetoacetate over modiﬁed nickel catalysts: effects of nickel
dispersion on the enantio-selectivity of catalysts
DONGHYUN JO, JAE SUNG LEE and KYUNG HEE LEE
Department of Chemical Engineering, Pohang University of Science and Technology (POSTECH),
San 31 Hyoja-Dong, Pohang 790-784, South Korea
Received 21 May 2004; accepted 9 June 2004
Abstract—Enantio-differentiating hydrogenation of methyl acetoacetate was performed over the
supported nickel catalysts modiﬁed by the solution of (R,R)-tartaric acid or (S)-malic acid and
NaBr. The reduction temperature of supported nickel was the most important factor determining the
enantio-selectivity of catalysts. The reduction temperature changed the nickel dispersion, by which
the quantity and coverage of modiﬁer adsorption were varied. The enantio-selectivity of modiﬁers
both (R,R)-tartaric acid and (S)-malic acid were compared at various reduction temperatures. (R,R)-
tartaric acid with two hydroxyl groups in a molecule showed an optimum coverage on the nickel
surface that gave the maximum ee value. The maximum ee value was 72% at the reduction temperature
of 973 K. In contrast, (S)-malic acid with one hydroxyl group in a molecule showed a monotonous
decrease in ee and decreasing amounts of adsorbed modiﬁer with increasing reduction temperatures.
Keywords: Enantio-differentiating hydrogenation; tartaric acid; malic acid; methyl acetoacetate.
The synthesis of optically pure chemicals is a very important step in pharmaceutical,
agricultural and ﬁne chemical processes [1, 2]. Various methods are used to
obtain optically active compounds such as chiral resolution, chiral transformation,
intermolecular chiral transfer and chiral multiplication. Among these methods,
chiral multiplication can be achieved only by chiral catalysis . As a large amount
of chiral molecules can be produced in one active site, chiral catalysis is a cheap
and environment-friendly process.
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