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The materials of catalyst supports of this study are divided
into inorganically activated γ-Al2O3 and organic polymer.
Asymmetrical compounds were adsorbed on γ-Al2O3 support and
asymmetricall modified the polymer supports, by chemical and
chemical rection, respectively. Using these catalysts,
hydrogenation methyl acetoacetate to produce asymmetric
2-methyl- hydroxybutyrate. Both the experimental results and
theoretical analysis ones indicated that the best formation of
asymmetric compound was affect by accepting of P and donating
of B electrons on the sites of Ni-P and Ni-B and induced the
mono-molecular adsorption on the active sites of catalyst .
Polymer supports are divided into straight-chain and cross-
chain, both of which were modified by chemical bonding from two
compounds which contained one and two asymmetrically active For
straight-chain asymmetrically modified catalysts of the polymer
support, the Na-compounds, temperature and time effect of
pretreatment had the best reactivity and optical yield when Na-
compouds was NaCl, 60℃and 8hr, then the effect of temperature
, time of Pd(II) ion exchange were obtained from 60℃, 18hr
which were the best choice for asymmetric hydrogenation. For
cross-chain asymmetrically modified catalysts of polymer
support, the reactivity and optical yield of hydrogenation
increased when the time of chemically asymmetricmodification
increased. The activity of the catalyst decayed for repeated
hydrogenations of MAA, and optical yield only decreased
slightly. The results of both experiment results and
theoretical model, the value n was 1 and two palladium atoms
adsorbed on the asy- metrically modified one active site of
polymer support. it means that the palladium atoms were packed
on the modified active site of polymer support in the form of
atom clusters.
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