Ex parte Takanohashi et al.

Board of Patent Appeals and Interferences

Feb 27, 1998

08002513 (B.P.A.I. Feb. 27, 1998)

Application for patent filed January 8, 1993. 1
According to appellants, this application is a continuation of
Application 07/866,092, filed April 6, 1992; which is a
continuation of Application 07/723,653, filed June 26, 1991;
which is a continuation of Application 07/204,527, filed June
8, 1988; all abandoned.
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THIS OPINION WAS NOT WRITTEN FOR PUBLICATION
The opinion in support of the decision being entered
today (1) was not written for publication in a law
journal and (2) is not binding precedent of the Board.
Paper No. 78
UNITED STATES PATENT AND TRADEMARK OFFICE
________________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
________________
Ex parte KUNIO TAKANOHASHI, MITSUTAKA TANAKA
and TORU YAMANO
________________
Appeal No. 95-0334
Application 08/002,5131
________________
HEARD: February 6, 1998
________________
Before KIMLIN, JOHN D. SMITH and CAROFF, Administrative Patent
Judges.
KIMLIN, Administrative Patent Judge.
DECISION ON APPEAL
Appeal No. 95-0334
Application 08/002,513
-2-
This is an appeal from the final rejection of claims 1
and 3-6, all the claims remaining in the present application.
Claim 1 is illustrative:
1. A method of preparing L-ascorbic acid, which
comprises allowing an acid to act on 2-keto-L-gulonic acid in
a mixed solvent consisting essentially of an inert organic
solvent and an aliphatic ketone in the presence of water and a
surfactant wherein the volume of the aliphatic ketone in the
mixed solvent is in a range of 0.02 to 0.3 relative to the
volume of the inert organic solvent, and wherein the amount of
water is 1.5 to 3.5 times as much in molar ratio relative to
2-keto-L-gulonic acid, and the amount of the acid is 0.5 to 2
times as much in molar ratio relative to 2-keto-L-gulonic
acid.
The examiner relies upon the following references as
evidence of obviousness:
Bassford, Jr. et al. (Bassford) 2,462,251 Feb. 22, 1949
Tanaka et al. (Japanese '217) 43-009217 Apr. 16, 1968
(Japanese Patent Publication)
Fujiwara et al. (Fujiwara) 48-15931 May 28, 1973
(Japanese Patent Application)
Appellants' claimed invention is directed to a method of
preparing L-ascorbic acid. The method entails reacting acid
with 2-keto-L-gulonic acid (GA) in a reaction medium
consisting essentially of an inert organic solvent, water, a
surfactant and an aliphatic ketone, such as acetone.
According to appellants, the presence of an aliphatic ketone
in the reaction medium allows for L-ascorbic acid to be made
Appeal No. 95-0334
Application 08/002,513
-3-
in yields comparable to prior art methods wherein diacetone-2-
keto-L-gulonic acid (DAGA) is used as the starting material.
Appealed claims 1 and 3-6 stand rejected under 35 U.S.C.
§ 103 as being unpatentable over Fujiwara in view of Bassford
and Japanese '217.
Upon thorough review of the opposing arguments presented
by appellants and the examiner, we concur with appellants that
the examiner has failed to establish a prima facie case of
obviousness for the claimed subject matter. Accordingly, we
will not sustain the examiner's rejection.
The examiner recognizes that Fujiwara discloses making
L-ascorbic acid from either DAGA or GA, but without an
aliphatic ketone being present in the starting reaction
medium. To remedy this deficiency in Fujiwara, the examiner
relies upon the disclosures of Bassford and Japanese '217.
Bassford teaches that when L-ascorbic acid is prepared from
DAGA, a ketone, such as acetone, is liberated and dissolves in
the solvent layer, thereby facilitating its removal from the
reaction medium. Japanese '217 incorporates acetone in a
reaction medium comprising DAGA to dissolve intermediate ester
compounds. Based on the disclosures of Bassford and Japanese
'217, the examiner concludes that it would have been obvious
Appeal No. 95-0334
Application 08/002,513
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for one of ordinary skill in the art to add acetone to the
reaction medium of Fujiwara.
We agree with appellants that neither Bassford nor
Japanese '217 would have provided the requisite motivation to
add an aliphatic ketone, such as acetone, in the claimed
process of using GA as the starting material for making L-
ascorbic acid. Like appellants, we find that Bassford
provides a "teaching away" for doing so. Bassford teaches
that the solvent forms a separate layer above the reaction
medium, and it is into such solvent layer that the ketone is
dissolved upon formation in the reaction medium. Since
Bassford teaches that the dissolution of the ketone in the
solvent layer facilitates its removal from the reaction
medium, we concur with appellants that the teaching of
Bassford would not have motivated one of ordinary skill in the
art to add such a component, acetone, to the reaction medium.
Concerning Japanese '217, this reference is directed to
the use of DAGA, not appellants' GA, as the starting material
for preparing L-ascorbic acid. While Japanese '217 adds
acetone to the reaction medium for dissolving intermediate
ester compounds formed by the reaction of DAGA and acid, the
examiner has not established on this record that similar ester
Appeal No. 95-0334
Application 08/002,513
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intermediates are formed during appellants' reaction of GA and
acid. In the absence of any teaching or suggestion in the
prior art that similar, intermediate ester compounds are
formed during the reaction of GA and acid, there would have
been no motivation for one of ordinary skill in the art to
incorporate acetone in the reaction medium. Furthermore, as
argued by appellants, Japanese '217 adds a C -C aliphatic6 10
alcohol or C -C alicyclic alcohol to the reaction medium, and5 6
the present claim language "consisting essentially of"
precludes the presence of such alcohols in the claimed
reaction medium. We note that the examiner has not rebutted
appellants' argument pertaining to the "consisting essentially
of" language.
In our view, the examiner's underlying rationale for the
conclusion of obviousness is more an explanation, with the
benefit of appellants' specification disclosure, why
appellants' process achieves an improved yield of L-ascorbic
acid, than why it would have been obvious for one of ordinary
skill in the art to employ an aliphatic ketone in the starting
reaction medium of the claimed process. Manifestly, this
approach necessitates the use of impermissible hindsight.
Appeal No. 95-0334
Application 08/002,513
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In conclusion, based on the foregoing, the examiner's
decision rejecting the appealed claims is reversed.
REVERSED
MARC L. CAROFF )
Administrative Patent Judge )
)
)
)
EDWARD C. KIMLIN ) BOARD OF PATENT
Administrative Patent Judge ) APPEALS AND
) INTERFERENCES
)
)
JOHN D. SMITH )
Administrative Patent Judge )
Appeal No. 95-0334
Application 08/002,513
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