Ex Parte Catani et al

Board of Patent Appeals and Interferences

Jul 28, 2008

10213387 (B.P.A.I. Jul. 28, 2008)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte
STEVEN J. CATANI, MARK R. HUBER, and NICHOLAS M. VERNON
__________

Appeal 2008-3326
Application 10/213,387
Technology Center 1600
__________

Decided: July 28, 2008
__________

Before TONI R. SCHEINER, ERIC GRIMES, and RICHARD M.
LEBOVITZ, Administrative Patent Judges.

GRIMES, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to a method
for recovering sucralose from a solution. The Examiner has rejected the
claims as obvious. We have jurisdiction under 35 U.S.C. § 6(b). We affirm.
BACKGROUND
“Sucralose, 4,1',6'-trichloro-4,1',6'-trideoxygalactosucrose, a
sweetener with a sweetness intensity several hundred times that of sucrose,
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Application 10/213,387

is made from sucrose by replacing the hydroxyl groups in the 4, 1', and 6'
positions with chlorine” (Spec. 1). Sucralose synthesis “approaches
typically yield a product that contains related substances in addition to
sucralose. Producing sucralose having low levels of related substances
involves a number of sequential recovery steps” (id.).
“Crystallization is widely used to recover compounds, including . . .
sucralose … by inducing the formation of crystals in a solution, followed by
separating the crystals from the remaining solution (the ‘mother liquor’)”
(id. at 1-2). “In a sequential crystallization, the sucralose crystal material
obtained at each crystallization step is dissolved in water and an additional
crystallization is performed on the solution thereby obtained. After each
subsequent crystallization, the sucralose crystals obtained will contain lower
amounts of related substances, since there are less related substances present
that could be potentially introduced into the crystals. Similarly, the mother
liquor at each stage also has a lower ratio of related substances to sucralose
than the mother liquors obtained at earlier crystallization steps.” (Id. at 2.)
The Specification discloses the “return of the mother liquor to the
same crystallization process step from which it originated is one aspect of
the current invention. . . . [A] significant portion of the mother liquor can be
recycled to increase yield and reduce related substances level in the end
product, e.g., sucralose” (id. at 3). The Specification also discloses that “up
to a certain level, the impact of related substances on yield is insignificant”
(id.).
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DISCUSSION
1. Claims 1-3, 5-10, 12-21, 23-25 and 39-42 are pending and on appeal.
Claims 1, 3, and 6 are representative and read as follows:
Claim 1: A method for recovering sucralose from a solution
comprising at least sucralose and related substances, the process comprising
the following sequential steps:
(a) providing to a crystallizer vessel a virgin aqueous solution
comprising at least sucralose and related substances;
(b) inducing the formation of sucralose crystals in the crystallizer
vessel to yield a slurry;
(c) removing a portion of the slurry;
(d) separating crystalline sucralose and a mother liquor from the
portion of the slurry;
(e) combining a portion of the mother liquor with the remaining slurry
along with an additional portion of virgin solution to produce an admixture
solution in the vessel,
wherein the ratio of the combined portion of the mother liquor to the
total mother liquor is a positive number less than or equal to 0.9933 -
0.0321x - 0.0126x2
wherein x is a number between 0 and 100 and is obtained by taking a
value provided by dividing the weight percent of related substances in the
virgin solution by the sum of the weight percent of sucralose and related
substances in the virgin solution and multiplying the value by 100; and
(f) repeating steps (b)-(d) at least once.

Claim 3: The method of claim 1, wherein said slurry is kept in a
suspended state by continuous agitation and pumping.

Claim 6: The method of claim 1, wherein said method is performed
as a process selected from the group consisting of continuous processes and
semi-continuous processes.

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3. OBVIOUSNESS
Claims 1-3, 5-10, 12-21, 23-25, and 39-42 stand rejected under 35
U.S.C. § 103 as obvious in view of Navia1 and Ault.2 The claims have been
argued in three groups: Claims 2, 5, 7-9, 12, 13, 15-17, 19, 20, 23-25, 39,
and 41 will stand or fall with claim 1; claims 10 and 18 will stand or fall
with claim 3; and claims 14, 21, 40 and 42 will stand or fall with claim 6.
37 C.F.R. § 41.37(c)(1)(vii).
The Examiner relies on Navia as disclosing “the isolation of sucralose
from a crude mixture, wherein an aqueous solution of the crude product …
is seeded with sucralose crystals … and allowed to crystallize,” and
subsequently, the “crystalline sucralose is separated and the mother liquor
can be recycled into subsequent recrystallizations ” (Ans. 3). The Examiner
finds that Navia does not teach adjusting the percentage of related
substances to a certain value (id. at 4). The Examiner relies on Ault as
disclosing that sometimes “crystallization will not occur when a solution is
cooled since the impurities present act as a protective colloid thereby
preventing crystallization of the desired product” (id.).
The Examiner concludes that the claimed process would have been
obvious to one of ordinary skill in the art “since the process steps are seen to
be taught in the prior art” (id.). The Examiner finds that “[o]ne of ordinary
skill in the art would be motivated to use these steps, especially adjusting the
percentage of related substances relative to sucralose in the slurry … since

1 Navia et al., US 5,498,709, Mar. 12, 1996.
2 Ault, Techniques and Experiments for Organic Chemistry, Second Edition,
1976, Holbrook Press, Inc, Boston, pp. 19-27.
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Ault teaches that impurities can prevent crystallization of the product” and
that it “is well within the purview of one of ordinary skill in the art to adjust
the percentage of the related substances to an optimal level that gives
maximum recovery of sucralose” (id.).
We conclude that the Examiner has set forth a prima facie case that
claim 1 would have been obvious to the ordinary artisan. Navia discloses “a
process for producing sucralose from sucralose-6-ester” that includes
recovering the sucralose by crystallization (Navia, abstract). Navia
describes crystallization of sucralose as follows:
This aqueous solution . . . was diluted with fresh ethyl acetate.
The solution was seeded with sucralose crystals and allowed to
stand and crystallize. . . . Additional crops were obtained by
repeatedly evaporating the solvent and redissolving the syrup in
fresh ethyl acetate. . . . Additional material may be obtained in
subsequent crops or by recycle of the mother liquor into
subsequent crystallizations.

(Id. at col. 9, ll. 23-35.) Navia also describes crystallization of sucralose
from water, as follows:
The solution was concentrated to about 65% sucralose, cooled
to ambient temperature, seeded with sucralose crystals, and
allowed to crystallize while stirring over 5 days. The crystalline
slurry was concentrated slightly by vacuum distillation of water
to about 70-75% sucralose and the crystallization continued a
further 24 hours. The crystalline product was recovered by
filtration.

(Id. at col. 9, ll. 37-49.) Navia also discloses that the mother liquor resulting
from crystallization of sucralose from water “may be used for recycle to
obtain additional material” (id. at col. 10, ll. 15-27).
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Ault discloses that “[o]ccasionally, crystallization will not occur when
a solution is cooled, even though it is supersaturated. The most stubborn
cases are explained in terms of impurities, or ‘tar,’ acting as a protective
colloid” (Ault, p. 27).
We agree with the Examiner that it would have been prima facie
obvious to one of ordinary skill in the art at the time the invention was made
to combine the teachings of Navia and Ault and thereby arrive at the
invention of claim 1. Navia discloses the crystallization of sucralose from
aqueous solutions and also discloses that, after a first crystallization,
additional crystallized sucralose may be obtained by recycling the mother
liquor into subsequent crystallizations. In view of this disclosure, it would
have been obvious to one of skill in the art to recycle the mother liquor into
a second sucralose solution for crystallization. Those skilled in the art
would recognize that “recycl[ing] of the mother liquor into subsequent
crystallizations” (Navia, col. 9, ll. 34-35) is a suggestion to add the mother
liquor to an additional portion of virgin solution, as recited in claim 1, i.e.,
recycle would imply that the solution is passed through the process again,
rather just re-extracted.
Navia does not teach separating only a portion of a particular
crystallized slurry and combining the remaining slurry with mother liquor
and additional virgin solution. Such a limitation would have been obvious to
the skilled artisan, however, because Navia teaches seeding aqueous
sucralose solutions with sucralose crystals before crystallization. Therefore,
it would have been obvious to those skilled in the art to retain a portion of a
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crystallized sucralose slurry and add it to the mother liquor and additional
virgin solution so as to provide a source of sucralose seed crystals.
We agree with the Examiner (Ans. 4) that adjusting the amount of
mother liquor added to the slurry and virgin solution is merely optimization
of a result-affecting variable and therefore obvious in the absence of
unexpectedly superior results.
Appellants argue that the combination of Navia and Ault does not
support a prima facie case of obviousness because the references do not
suggest return of mother liquor to the same crystallizer (App. Br. 11-15) or
the introduction of additional virgin sucralose (id. at 15). More specifically,
Appellants argue that Navia discloses only the recycling of the mother liquor
to subsequent and not previous cyrstallizations (id. at 11), and that “Navia
does not teach or suggest returning mother liquor to the same crystallizer
that produced it” (id. at 12). Appellants also argue that Ault “provides a
disincentive to return impurities to the same crystallizer that produced the
mother liquor that contains them” (id. at 13). Appellants also argue that the
“cited references … fail to teach the additional recited step of introducing
additional virgin sucralose solution to the same crystallizer vessel as that to
which the portion of mother liquor is returned” (id. at 15).
We are not persuaded by these arguments. As discussed above, those
skilled in the art would have understood Navia’s suggestion to recycle
mother liquor to subsequent crystallizations to mean combining it with
virgin solution, not merely re-extracting it, and would have considered it
obvious to retain a portion of crystallized slurry to add to the combined
mother liquor/virgin solution as a source of seed crystals. “[T]he
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‘motivation-suggestion-teaching’ test asks not merely what the references
disclose, but whether a person of ordinary skill in the art, possessed with the
understandings and knowledge reflected in the prior art, and motivated by
the general problem facing the inventor, would have been led to make the
combination recited in the claims.” In re Kahn, 441 F. 3d 977, 988 (Fed.
Cir. 2006). See also KSR Int’l Co. v. Teleflex Inc., 127 S.Ct. 1727, 1741
(2007) (The obviousness analysis “can take account of the inferences and
creative steps that a person of ordinary skill in the art would employ.”);
Dystar Textilfarben Gmbh & Co. Deutschland KG v. C.H. Patrick Co., 464
F.3d 1356, 1367 (Fed. Cir. 2006) (The “suggestion test is in actuality quite
flexible and not only permits, but requires, consideration of common
knowledge and common sense.”).
As to the claim requirement that the vessel used for the initial
crystallization is re-used in the recycling step, one of skill in the art would
recognize that the slurry portion, mother liquor, and virgin solution are
combined in a vessel and treated the same way whether the same vessel that
was used for the initial crystallization is re-used or a new vessel is used.
Appellants have not shown that re-using the same vessel for multiple
crystallizations provides unexpectedly superior results. We conclude that
one of skill in the art would have considered the claimed feature of
“combining a portion of the mother liquor with the remaining slurry along
with an additional portion of virgin solution to produce an admixture
solution in the vessel” to be obvious in view of the cited references,
considered as a whole.
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Appellants also argue that the “claims recite a specific upper limit on
the amount of mother liquor returned to the crystallizer” and that there “is no
teaching or suggestion in either Navia or Ault for such a limitation” (App.
Br. 14). Appellants further argue that “this limitation would not properly be
considered the result of mere optimization, since optimization must be with
respect to a known result-effective variable, and return of a portion of
mother liquor to the same crystallizer was not a known result effective
variable at the time of the invention” (id.).
We do not find this argument to be persuasive. As set forth above, we
conclude that combining recycled mother liquor with virgin solution for a
second crystallization would have been obvious to one of skill in the art. In
addition, Ault teaches that a high level of impurities can interfere with
crystallization. We agree with the Examiner that the concentrations of the
two components in a second crystallization would have been understood by
one of skill in the art to affect the crystallization and thus be “result effective
variables” that would be obvious to optimize. “It is not inventive to discover
the optimum or workable ranges by routine experimentation.” In re Geisler,
116 F.3d 1465, 1470 (Fed. Cir. 1997).
With regard to dependent claim 3, Appellants argue that this claim
recites “that the slurry is kept in a suspended state by continuous agitation
and pumping” and that neither of the cited references “discloses or suggests
that crystallization of sucralose may be effected, with good purity and yield
as provided by the present invention, under these conditions” (App. Br. 14).
We do not find this argument to be persuasive. As set forth above,
Navia discloses that a sucralose solution was “cooled to ambient
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temperature, seeded with sucralose crystals, and allowed to crystallize while
stirring over 5 days” to form a slurry (Navia, col. 9, ll. 43-45; emphasis
added). Thus, Navia discloses cystallization of a slurry kept in a suspended
state by continuous agitation. While Navia does not teach pumping the
slurry while it crystallizes, we agree with the Examiner (Ans. 4) that Navia’s
teaching of stirring would have suggested this limitation as a matter of
routine optimization of the disclosed process.
With regard to claim 6, Appellants argue that neither of the cited
references discloses or suggests “a continuous or semi-continuous process”
as recited in the claim (App. Br. 14).
We do not find this argument to be persuasive. The Specification
defines a “semi-continuous process” as “a procedure in which a fixed
amount of materials are introduced into a process, and the products obtained
from this fixed amount of input are recovered prior to the addition of more
input material” (Spec., para. 0034).
As set forth above, that Navia suggests carrying out a first
crystallization reaction in a vessel, then carrying out a second crystallization
reaction in the same vessel that includes recycled mother liquor, virgin
solution, and reserved slurry. The process suggested by the prior art
reasonably appears to be a “semi-continuous process” as that term is defined
in the Specification.
Appellants further argue (App. Br. 16-17) that they have provided a
showing of unexpected results in the Huber Declaration (included in the
Evidence Appendix attached to the Appeal Brief). In particular, Appellants
argue that the Huber Declaration provides evidence that the “return of a
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portion of sucralose mother liquor from a given crystallizer back to that
same crystallizer results in a higher product yield (with maintenance of the
same level of product purity) than when it is routed to crystallizers either
earlier or later in the process” (App. Br. 16).
We are not persuaded by Appellants’ argument of unexpected results.
The Huber Declaration describes a computer model of a continuous
sucralose crystallization process that includes four crystallizers (Huber Decl.
¶¶ 4-6). Mr. Huber states that, according to the model, a four-step
crystallization process produces a higher yield when a portion of the mother
liquor in the second and third crystallizations is returned to the crystallizer
from which it originated rather than being routed to the preceding
crystallizer (id. ¶ 7).
Mr Huber states that “[s]uch a step, which necessarily involves adding
impurities back to the crystallizer in which those same impurities were
previously separated form the product being purified, is, in [his] opinion,
highly counterintuitive” (id.).
Appellants’ evidence is not sufficient to overcome the Examiner’s
prima facie case of obviousness. It may be true that the prior art references
provide no reason to expect that, in a sequential crystallization process, the
return of a portion of mother liquor to the crystallizer from which it
originated, as compared with routing that portion of mother liquor to the
preceding crystallizer, would improve the final product yield, as shown in
the Huber Declaration. The results shown in the Declaration therefore might
be unexpected based on the prior art.
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However, this showing does not overcome the obviousness rejection
because the process described in the Huber declaration is not the process
defined by the claims on appeal. First, the instant claims require that the
amount of mother liquor returned to the same crystallizer be determined
based on the amount of “related substances” and sucralose in the virgin
solution. Appellants have not pointed to any basis for concluding that the
computer modeling experiment described in the Huber Declaration included
the calculation, based on the amount of “related substances” required by the
instant claims.
“Although it is well settled that comparative test data showing an
unexpected result will rebut a prima facie case of obviousness, the
comparative testing must be between the claimed invention and the closest
prior art.” In re Fenn, 639 F.2d 762, 765 (CCPA 1981) (emphasis added).
Appellants have not shown that the data in the Huber Declaration represents
a comparison of the process defined by the claims on appeal with the prior
art.
In addition, the claims on appeal are not limited to a sequential
crystallization process. “Claims which are broad enough to read on obvious
subject matter are unpatentable even though they also read on nonobvious
subject matter.” In re Lintner, 458 F.2d 1013, 1015 (CCPA 1972). See also
In re Muchmore, 433 F.2d 824, 826 (CCPA 1970) (claim held “too broad in
the sense of section 103, since it reads on both obvious and unobvious
subject matter").
In the instant case, those skilled in the art would expect, based on
Navia, that recycling mother liquor to the crystallization vessel and adding
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more virgin solution to the vessel would enhance the yield obtained from the
total quantity of virgin solution that was crystallized. Thus, the instant
claims encompass the prior art process, suggested by Navia, of a repeated
crystallization process in one vessel. Appellants have not shown any
unexpected results for the one-vessel process suggested by the prior art and
encompassed by the claims. Thus, the claims encompass obvious subject
matter. In other words, the evidence of unexpected results is not
commensurate in scope with the claimed invention. See In re Dill, 604 F.2d
1356, 1361 (CCPA 1979) (“The evidence presented to rebut a prima facie
case of obviousness must be commensurate in scope with the claims to
which it pertains.”).
SUMMARY
The Examiner’s rejection is supported by the preponderance of the
evidence of record. We therefore affirm the rejection of claims 1-3, 5-10,
12-21, 23-25 and 39-42 under 35 U.S.C. § 103.
No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a).

AFFIRMED

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