Appeal 2007-0711
Reexamination 90/006,706
compound in order to improve the efficacy of the medicine per unit
quantity and to prevent drug-induced sufferings caused by adverse
reactions to the drug. For the separation of such an optical isomer
mixture, . . . the chromatographic methods known at present are of a
batch type and hence cannot avoid discontinuous and unstationary
operations, which is unsuitable for the mass processing. Further,
this chromatographic method has another defect in that since a large
amount of an eluent is necessitated and the concentration of the
intended compound in the eluate is low, much energy and
complicated steps are necessitated for the recovery.
As its objectives, Negawa instructs (Negawa, col. 1, ll. 51-58):
An object of the present invention is to provide a novel process
which can separate optical isomers and a solvent efficiently from a
large amount of a mixture comprising the optical isomers. Another
object of the present invention is to provide a process for efficiently
separating each of optical isomers and a solvent from a large amount
of a mixture comprising the optical isomers and also reusing the
recovered solvent.
To meet it objectives, Negawa teaches (Negawa, col. 1, l. 61, to col. 2, l. 14;
emphasis added):
The invention which solves the above problem relates to a
process for recovering optical isomers and a solvent in optical
resolution by introducing a liquid containing an optical isomer
mixture and an eluent into a packed bed containing packings for
optical resolution, having both ends connected to each other through
a fluid passage to be endless and circulating the liquids therein by
one-way flow, and simultaneously recovering a liquid containing one
optical isomer and a liquid containing the other optical isomer which
are separated from the packed bed, characterized by arranging an inlet
for the eluent, an outlet for a liquid (extract) containing an easily
adsorbable optical isomer, an inlet for the liquid containing an optical
isomer mixture, and an outlet for a liquid (raffinate) containing a
difficultly adsorbable optical isomer in this order in the direction of
liquid flow onto the packed bed, and recovering the solvent and
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