Appeal 2007-0711
Reexamination 90/006,706
optical isomers from the extract and/or raffinate thus obtained with a
simulated moving bed system such that the inlets and the outlets are
intermittently and successively moved in the direction of liquid flow
in the bed.
Negawa (patented July 18, 1995) claims to be first to employ a
simulated moving bed system to separate optical isomers (Negawa, col. 3, ll.
20-27):
The simulated moving bed system per se is well known as
described . . . . However, the simulated moving bed system has
heretofore been employed only for the production of fructose,
separation of maltose and recovery of co-enzymes and no process has
been described at all for separating optical isomers by this system.
Negawa suggests that the optical isomers of various types of
medicines can be separated using the simulated moving bed processes
(Negawa, col. 4, ll. 32-34). With regard to the solvents useful as the eluent,
i.e., the achiral liquid mobile phase composition, in simulated moving bed
processes for separation of optical isomers, Negawa teaches (Negawa, col. 4,
ll. 22-28; emphasis added):
The eluents to be fed through the inlet for an eluent include, for
example, organic solvents such as alcohols, e.g. methanol, ethanol and
isopropanol, hydrocarbons, e.g., hexane, and aqueous salt solutions
such as aqueous copper sulfate solution and aqueous perchlorate
solution. The eluent is suitably selected depending on the kind of
compounds to be optically resolved.
Negawa provides several examples of simulated moving bed processes for
separating optically active isomers all of which employ mixtures of
isopropanol and hexane as the eluent:
… 1,3-butanediol diacetate…was fed as a liquid containing an optical
isomer mixture. … [A] liquid mixture of hexane and isopropanol
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