Appeal No. 2001-0697 Page 6
Application No. 09/125,033
select the elements from the cited prior art references for combination in the
manner claimed.’” Ecolochem, Inc. v. Southern Calif. Edison Co., 227 F.3d
1361, 1375, 56 USPQ2d 1065, 1075 (Fed. Cir. 2000) (quoting In re Rouffet, 149
F.3d 1350, 1357, 47 USPQ2d 1453, 1456 (Fed. Cir. 1998)).
Having considered the record, we agree with Appellants that the cited
references do not provide the required motivation to substitute a sodium- or
calcium-containing base (e.g., sodium hydroxide or calcium hydroxide) for the
ammonia used in Walkup’s process. Walkup discloses that the yield of lactic
acid ester is “limited by the conversion of ammonium lactate to lactic acid and
NH3.” Column 6, lines 40-41. This conversion can be shifted toward the
products “with the removal or reaction of the NH3 that is released from the
ammonium lactate. The CO2 effectively does this by reacting with NH3.
Surprisingly, the CO2 in solution also provides sufficient acidity to catalyze the
formation of the ester.” Column 6, lines 41-48.
Walkup also speculates that “[a] possible explanation of the mechanism of
CO2 in the above process may stem from CO2 and aqueous NH3 forming a rather
unstable compound (ammonium bicarbonate, NH4HCO3). . . . Further,
ammonium lactate itself is rather unstable as evidenced by the odor of NH3 over
heated, concentrated ammonium lactate solutions. Excess CO2 at pressure in
the process of the invention probably makes the ammonium bicarbona te more
stable at higher temperatures, and shifts the equilibrium toward the ammonium
bicarbonate salt. . . . Thus, the more stable bicarbonate plus excess CO2 may be
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