Ex Parte Nisbet et al

Board of Patent Appeals and Interferences

Mar 8, 2011

12017289 (B.P.A.I. Mar. 8, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
UNITED STATES DEPARTMENT OF COMMERCE
United States Patent and Trademark Office
Address: COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
APPLICATION NO. FILING DATE FIRST NAMED INVENTOR ATTORNEY DOCKET NO. CONFIRMATION NO.
12/017,289 01/21/2008 Timothy Michael Nisbet TS1848 (US) 6104
7590 03/08/2011
Shell Oil Company
910 Louisiana
Houston, TX 77002
EXAMINER
KAHN, RACHEL
ART UNIT PAPER NUMBER
1766
MAIL DATE DELIVERY MODE
03/08/2011 PAPER
Please find below and/or attached an Office communication concerning this application or proceeding.
The time period for reply, if any, is set in the attached communication.
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte TIMOTHY MICHAEL NISBET,
GARO GARBIS VAPORCIYAN,
CORNELIS LEONARDUS MARIA VROUWENVELDER, and
PAUL WOOD
__________

Appeal 2010-011769
Application 12/017,289
Technology Center 1700
__________

Before TONI R. SCHEINER, DONALD E. ADAMS, and
JEFFREY N. FREDMAN, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL1
This is an appeal under 35 U.S.C. § 134 involving claims to a method
for preparing diaryl carbonate. We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

1 The two-month time period for filing an appeal or commencing a
civil action, as recited in 37 C.F.R. § 1.304, or for filing a request
for rehearing, as recited in 37 C.F.R. § 41.52, begins to run from
the “MAIL DATE” (paper delivery mode) or the
“NOTIFICATION DATE” (electronic delivery mode) shown on
the PTOL-90A cover letter attached to this decision.
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Statement of the Case
Background
“Diaryl carbonates are important starting materials for the production
of aromatic polycarbonates” (Spec. 1, ll. 5-6). “The present invention relates
to a process for the preparation of diaryl carbonate by reaction of an
aromatic alcohol with a dialkyl carbonate” (Spec. 1, ll. 1-3).
The Claims
Claims 1-7 and 9 are on appeal. Claim 1 is representative, and the
remaining claims have not been argued separately and therefore stand or fall
together with claim 1. 37 C.F.R. § 41.37(c)(1)(vii). Claim 1 reads as follows:
1. A process for the preparation of diaryl carbonate by
reaction of an aromatic alcohol with a dialkyl carbonate,
which dialkyl carbonate has been prepared by the reaction of
an alkanol and an alkylene carbonate, which process
comprises the following steps:
(a) passing an aromatic alcohol and a dialkyl
carbonate into a first transesterification zone to obtain a first
product stream containing diaryl carbonate, alkanol,
unconverted dialkyl carbonate and unconverted aromatic
alcohol;
(b) separating the first product stream into a diaryl
carbonate-rich product stream, an aromatic alcohol-rich
recycle stream and a second recycle stream comprising
alkanol, dialkyl carbonate and aromatic alcohol;
(c) feeding alkanol and alkylene carbonate into a
second transesterification zone to obtain a second product
stream comprising alkanediol and unconverted alkanol and
dialkyl carbonate;
(d) separating alkanediol from the second product
stream to yield an alkanediol product stream and a mixture
of dialkyl carbonate and unconverted alkanol;
(e) subjecting the mixture of dialkyl carbonate and
unconverted alkanol and the second recycle stream
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comprising alkanol, dialkyl carbonate and aromatic alcohol
to the same distillation to obtain an alkanol stream as the
lower-boiling fraction and a contaminated stream
comprising dialkyl carbonate and aromatic alcohol as the
higher-boiling fraction;
(f) recycling the alkanol stream of step e) to the
second transesterification zone; and
(g) passing the contaminated stream comprising
dialkyl carbonate and aromatic alcohol, and the aromatic
alcohol-rich recycle stream to the first transesterification
zone.

The issues
A. The Examiner rejected claims 1-5 under 35 U.S.C. § 103(a) as
obvious over Inaba2,3 and Nisoli4 (Ans. 3-8).
B. The Examiner rejected claims 6, 7, and 9 under 35 U.S.C. § 103(a) as
obvious over Inaba, Nisoli and Brydson5 (Ans. 9).
A. 35 U.S.C. § 103(a) over Inaba and Nisoli
The Examiner finds that “Inaba discloses a process for the continuous
production of aromatic carbonate” (Ans. 3). The Examiner finds that
Due to the inclusion of the extra distillation column “R”
where phenol is removed from the product stream of pipe
50, Inaba fails to fulfill the instant limitation (in step “e”)
reciting that aromatic alcohol (phenol) is included in the
recycle stream (pipe 54) comprising DMC and MeOH from
step “b”. It is clear that, if distillation column R (and pipe
54) were removed, the process taught by Inaba would fulfill

2 Inaba et al., JP 9040616, published Feb. 10, 1997.
3 The Examiner provided a machine translation in the April 2,
2009, non-final rejection.
4 Nisoli et al., US 6,315,868 B1, issued Nov. 13, 2001.
5 Brydson, J., PLASTICS MATERIALS 556-559 (1999).
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the limitations of the process disclosed in instant claim 1. If
“R” and pipe 54 were removed, pipe 50 (instead of pipe 54)
would connect with pipe 43, and together they would lead to
column N. Once in N, phenol (which has a higher boiling
point than DMC) would be in the higher boiling fraction
with DMC (pipe 46), and would then be recycled with the
DMC stream, via pipe 47, back to the first transesterification
zone

(Ans. 7).
The Examiner finds that “Nisoli teaches that dimethyl carbonate is a
useful starting material in the synthesis of aromatic polycarbonates (column
1, lines 12-13). Nisoli also teaches that dimethyl carbonate is often obtained
in a mixture with methanol” (Ans. 7). The Examiner finds that “the two
compounds can often be difficult to separate by distillation (known methods
involve at least two distillation columns) . . . The method taught by Nisoli
eliminates the need for a second distillation column (along with a reboiler
and condenser), thus simplifying the process and reducing expense” (Ans.
7).
The Examiner finds it obvious to “modify Inaba by removing
distillation column R (and pipe 54) in order to take advantage of phenol's
ability to facilitate the separation of DMC and methanol” (Ans. 8). The
Examiner finds that “one of ordinary skill in the art at the time the invention
was made would have been motivated to modify the process of Inaba by
removing distillation unit R, in order to simplify the process and reduce the
expense associated with an extra distillation unit” (Ans. 8).
Appellants contend that “[a]ssuming, arguendo, that one of ordinary
skill in the art wanted to combine these references, then the teaching of the
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'868 patent would have taught that the column O could be removed by
changing column N such that it had a side draw. Then, column N could have
been operated in the same way the column in the ‘868 patent was operated”
(App. Br. 5).
Appellants contend that the “Examiner has failed to take the teachings
of the prior art as a whole, but instead has used hindsight and latched onto
specific language in the references to come to a desired conclusion” (App.
Br. 6). Appellants contend that there “are many features of the inventions
described in those references which the Examiner has opted to ignore, such
as the purity requirement of the extractive distillation agent, the method of
feeding the extractive distillation agent from the top and the mixture at the
middle of the column, and the necessity of a side draw, all taught by the ‘868
patent” (App. Br. 7).
In view of these conflicting positions, we frame the obviousness issue
before us as follows: Does the evidence of record support the Examiner’s
conclusion that the prior art renders claim 1 obvious?
Findings of Fact
1. Inaba teaches that a “method for producing an aromatic
carbonate comprises combining a previous process for producing a reaction
solution containing dimethyl carbonate from methanol as a starting raw
material, distilling and separating dimethyl carbonate from the reaction
solution and purifying it with a latter process” (Inaba abstract).
2. Figure 3 of Inaba, as annotated by the Examiner (Ans. 4), is
reproduced below:
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The annotated figure 3 shows a reaction process labeled with the reactants
and reaction products.
3. The Examiner finds that due “to the inclusion of the extra
distillation column ‘R’ where phenol is removed from the product stream of
pipe 50, Inaba fails to fulfill the instant limitation (in step ‘e’) reciting that
aromatic alcohol (phenol) is included in the recycle stream (pipe 54)
comprising DMC and MeOH from step ‘b’” (Ans. 7).
4. The Examiner finds that:
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If “R” and pipe 54 were removed, pipe 50 (instead of pipe
54) would connect with pipe 43, and together they would
lead to column N. Once in N, phenol (which has a higher
boiling point than DMC) would be in the higher boiling
fraction with DMC (pipe 46), and would then be recycled
with the DMC stream, via pipe 47, back to the first
transesterification zone.

(Ans. 7).
5. Nisoli teaches that “[d]imethyl carbonate is useful as a starting
material in the synthesis of aromatic polycarbonates. . . . Dimethyl carbonate
is often present in a mixture with methanol” (Nisoli, col. 1, ll. 11-16).
6. Nisoli teaches that “[k]nown methods for separating a dimethyl
carbonate/methanol mixture involve at least two distillation columns.
Therefore, there exists a need for a simplified and more economical process
for separating a dimethyl carbonate/methanol mixture” (Nisoli, col. 1, ll. 55-
59).
7. Nisoli teaches that the “known process of separating dimethyl
carbonate and methanol in an extractive distillation process involves more
than one distillation column, each column having a reboiler and an overhead
condenser” (Nisoli, col. 3, ll. 61-64).
8. Nisoli teaches that it “was unexpectedly found that removal of a
side stream comprising primarily dimethyl carbonate in an extractive
distillation column obviates the need for a second distillation column having
a reboiler and an overhead condenser thus greatly simplifying the process
and reducing expense” (Nisoli, col. 3, l. 64 to col. 4, l. 2).
9. Nisoli teaches that the “extractive distillation agent used in the
distillation is a compound that does not form an azeotrope with methanol or
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dimethyl carbonate, and which boils at a higher temperature than both
methanol and dimethyl carbonate . . . phenol is even more preferred” (Nisoli,
col. 5, ll. 3-13).
Principles of Law
The question of obviousness is resolved on the basis of underlying
factual determinations including: (1) the scope and content of the prior art;
(2) the level of ordinary skill in the art; (3) the differences between the
claimed invention and the prior art; and (4) secondary considerations of
nonobviousness, if any. Graham v. John Deere Co., 383 U.S. 1, 17 (1966).
“The combination of familiar elements according to known methods
is likely to be obvious when it does no more than yield predictable results.”
KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398, 416 (2007). “If a person of
ordinary skill can implement a predictable variation, § 103 likely bars its
patentability.” Id. at 417.
Analysis
The Examiner finds that Inaba teaches a process which is identical to
that claimed except that due “to the inclusion of the extra distillation column
‘R’ where phenol is removed from the product stream of pipe 50, Inaba fails
to fulfill the instant limitation (in step ‘e’) reciting that aromatic alcohol
(phenol) is included in the recycle stream (pipe 54) comprising DMC and
MeOH from step ‘b’” (Ans. 7; FF 3).
The Examiner finds that:
If “R” and pipe 54 were removed, pipe 50 (instead of pipe
54) would connect with pipe 43, and together they would
lead to column N. Once in N, phenol (which has a higher
boiling point than DMC) would be in the higher boiling
fraction with DMC (pipe 46), and would then be recycled
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with the DMC stream, via pipe 47, back to the first
transesterification zone.

(Ans. 7; FF 4).
Nisoli teaches, in a method of separation of DMC and methanol using
phenol, that “[k]nown methods for separating a dimethyl carbonate/methanol
mixture involve at least two distillation columns. Therefore, there exists a
need for a simplified and more economical process for separating a dimethyl
carbonate/methanol mixture” (Nisoli, col. 1, ll. 55-59; FF 5-6). Nisoli
teaches that it “was unexpectedly found that removal of a side stream
comprising primarily dimethyl carbonate in an extractive distillation column
obviates the need for a second distillation column having a reboiler and an
overhead condenser thus greatly simplifying the process and reducing
expense” (Nisoli, col. 3, l. 64 to col. 4, l. 2; FF 7).
Applying the KSR standard of obviousness to the findings of fact, we
agree with the Examiner that it would have been obvious to modify Inaba’s
process to remove the second distillation column for separation of methanol
and DMC and use a side draw for DMC as taught by Nisoli since Nisoli
teaches that this would result in a simplified and more economical process
(FF 5-8). Such a combination is merely a “predictable use of prior art
elements according to their established functions.” KSR, 550 U.S. at 417.
Appellants contend that “[a]ssuming, arguendo, that one of ordinary
skill in the art wanted to combine these references, then the teaching of the
'868 patent would have taught that the column O could be removed by
changing column N such that it had a side draw. Then, column N could have
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been operated in the same way the column in the ‘868 patent was operated”
(App. Br. 5).
We are not persuaded. Unlike columns R and N, which function to
distill and separate methanol and DMC, column O functions to separate
DMC and ethylene carbonate (see FF 2). Thus, to apply Nisoli’s teaching to
simplify the process of DMC separation from methanol by reducing the
number of columns from two to one and remove DMC with a side draw to
Inaba, the ordinary artisan would have reasonably removed one of the
columns which functioned to perform this process. The columns which
separate DMC and methanol in Inaba are columns R and N. The Examiner
reasonably explains that removal of column R would be motivated by the
improved efficiencies expected by Nisoli.
Appellants’ suggestion to remove column O is inconsistent with the
teachings of Nisoli, since column O separates ethylene carbonate from DMC
and recycles the DMC back to the earlier zone (see FF 2).
Appellants contend that the “Examiner has failed to take the teachings
of the prior art as a whole, but instead has used hindsight and latched onto
specific language in the references to come to a desired conclusion” (App.
Br. 6).
While we are fully aware that hindsight bias often plagues
determinations of obviousness, Graham v. John Deere Co., 383 U.S. at 36,
we are also mindful that the Supreme Court has clearly stated that the
“combination of familiar elements according to known methods is likely to
be obvious when it does no more than yield predictable results,” KSR, 550
U.S. at 401. The KSR reasoning is applicable here, where Nisoli expressly
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motivates the removal of one of the distillation columns involved in
separating methanol and DMC and the ordinary artisan would reasonably
find removal of column R obvious for improved efficiency and reduced cost
(FF 1-8).
Appellants contend that there “are many features of the inventions
described in those references which the Examiner has opted to ignore, such
as the purity requirement of the extractive distillation agent, the method of
feeding the extractive distillation agent from the top and the mixture at the
middle of the column, and the necessity of a side draw, all taught by the ‘868
patent” (App. Br. 7).
We are not persuaded. There are no limitations in claim 1 regarding
the purity of the extractive distillation agent, the method of feeding the
extractive distillation agent or the necessity of a side draw. “[L]imitations
are not to be read into the claims from the specification.” In re Van Geuns,
988 F.2d 1181, 1184 (Fed. Cir. 1993) (citing In re Zletz, 893 F.2d at 321).
To the extent that Appellants argument is that Nisoli performs a
different method than that of Inaba, we remain unpersuaded, since it is the
combination of references based on the suggestion of the prior art which
renders the claims obvious, not the entire disclosure of each reference. In
the instant case, Nisoli expressly teaches that it “was unexpectedly found
that removal of a side stream comprising primarily dimethyl carbonate in an
extractive distillation column obviates the need for a second distillation
column having a reboiler and an overhead condenser thus greatly
simplifying the process and reducing expense” (Nisoli, col. 3, l. 64 to col. 4,
l. 2; FF 8). This is a reasonably specific motivation which provides reasons
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for the ordinary artisan to remove the second distillation column in Inaba
which distilled dimethyl carbonate and methanol and use a side draw to
improve costs and simplify the process.
Conclusion of Law
The evidence of record supports the Examiner’s conclusion that the
prior art renders claim 1 obvious.
B. 35 U.S.C. § 103(a) over Inaba, Nisoli, and Brydson
The Examiner finds it obvious “to prepare the polycarbonate taught by
Inaba/Nisoli using Bisphenol A, as taught by Brydson, in order to prepare
the only polycarbonate of major commercial importance” (Ans. 9).
The Examiner provides sound fact-based reasoning for combining the
method of Brydson with that of Inaba and Nisoli (see Ans. 9). We adopt the
fact finding and analysis of the Examiner as our own. Appellants argue the
underlying obviousness rejection over Inaba and Nisoli, but Appellants do
not identify any material defect in the Examiner’s reasoning for combining
Brydson with Inaba and Nisoli. Since Appellants only argue the underlying
rejection which we affirmed above, we affirm this rejection for the reasons
stated by the Examiner.
SUMMARY
In summary, we affirm the rejection of claim 1 under 35 U.S.C. §
103(a) as obvious over Inaba and Nisoli. Pursuant to 37 C.F.R. §
41.37(c)(1)(vii)(2006), we also affirm the rejection of claims 2-5, as these
claims were not argued separately.
We affirm the rejection of claims 6, 7, and 9 under 35 U.S.C. § 103(a)
as obvious over Inaba, Nisoli, and Brydson.
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No time period for taking any subsequent action in connection with
this appeal may be extended under 37 C.F.R. § 1.136(a)(1).

AFFIRMED

alw

SHELL OIL COMPANY
910 LOUISIANA
HOUSTON, TX 77002