Ex Parte Wang

Board of Patent Appeals and Interferences

Nov 15, 2011

12290757 (B.P.A.I. Nov. 15, 2011)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________

Ex parte WEI WANG
__________

Appeal 2011-007411
Application 12/290,757
Technology Center 1600
__________

Before DEMETRA J. MILLS, ERIC GRIMES, and FRANCISCO C.
PRATS, Administrative Patent Judges.

GRIMES, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 involving claims to a process
for producing acetic acid. The Examiner has rejected the claims as obvious.
We have jurisdiction under 35 U.S.C. § 6(b). We affirm.
STATEMENT OF THE CASE
The Specification discloses that in known methods, “[a]romatic iodide
compounds are removed from acetic acid by palladium-gold acetoxylation
catalysts … [which] are expensive” (Spec. 2: 16-17). The Specification
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discloses “a method for removing iodobenzene compounds from acetic acid
… [by] contacting the acetic acid with palladium supported on a
macroreticular ion-exchange resin” (Id. at 2: 22-24).
Claims 5-9 are on appeal. Claims 6-9 have not been argued separately
and therefore stand or fall with claim 5. 37 C.F.R. § 41.37(c)(1)(vii). Claim
5 reads as follows:
5. A process for producing acetic acid, said process comprising:
(a) reacting methanol and carbon monoxide in the presence of a
carbonylation catalyst, a triphenylphosphine oxide stabilizer, methyl iodide,
water and methyl acetate to produce an acetic acid stream containing an
iodobenzene compound;
(b) flashing at least a portion of the acetic acid stream into a vapor
stream comprising acetic acid, water, methanol, methyl acetate, methyl
iodide and the iodobenzene compound, and a liquid stream comprising the
catalyst and the catalyst stabilizer;
(c) subjecting the vapor stream to a distillation to produce an acetic
acid product stream comprising acetic acid and the iodobenzene compound;
and
(d) contacting the acetic acid product stream with palladium supported
on a macroreticular ion-exchange resin to remove the iodobenzene.

Issue
The Examiner has rejected claims 5-9 under 35 U.S.C. § 103(a) as
being obvious in view of Watt1 and in view of Carey,2 or Jones,3 or Fish.4
The Examiner finds that Watt discloses that “triphen[yl]phosphines were
commonly used in acetic acid processes” (Answer 4) and that “iodide by-
products are also produced in the reaction” (id.). The Examiner finds that

1 Watt, US 6,686,500 B1, Feb. 3, 2004
2 Carey et al., US 6,197,997 B1, Mar. 6, 2001
3 Jones et al., US 5,344,976, Sept. 6, 1994
4 Fish et al., US 5,220,058, June 15, 1993
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Carey discloses a “process for removing iodide compounds from a liquid
carboxylic acid … obtained from the Group VIII noble metal catalyzed,
alkyl iodide co-catalyzed carbonylation of alcohols and/or their reactive
derivatives” (id. at 5). The Examiner finds that Carey discloses that
removing the iodide compound “comprises contacting the liquid carboxylic
acid … with a metal loaded ion-exchange resin … wherein the metal is one
or more of the metals silver, palladium or mercury” and the ion-exchange
resin can be a macroreticular ion-exchange resin (id.). The Examiner
concludes that “based on the above [cited references], the claimed process
step to remove iodide byproducts is known, well within the purview of those
of ordinary skill, and thus, prima facie obvious” (id. at 6). The Examiner
reasons that although the cited references “do not explicitly teach the
removal of iodobenzene, as instantly claimed, the removal of this particular
byproduct would be inherent in the process[ ] of Carey” (id.).
Appellant argues that the claimed process would not have been
obvious because none of the cited references recognize iodobenzene as an
impurity and therefore, it would not have been obvious to use palladium
supported on a macroreticular ion-exchange resin to remove it (Appeal Br.
3).
The issue presented is: Does the evidence of record support the
Examiner’s conclusion that it would have obvious to contact an acetic acid
product stream from Watt’s carbonylation process with palladium supported
on a macroreticular ion-exchange resin and thereby remove iodobenzene?
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Findings of Fact
1. Watt discloses “a process for the production of acetic acid by
reacting carbon monoxide with methanol … in a liquid reaction composition
comprising an iridium carbonylation catalyst, methyl iodide, methyl acetate,
water and acetic acid … [and] a monodentate phosphine oxide compound”
(Watt, abstract).
2. Watt discloses that a “preferred monodentate phosphine oxide
compound … is triphenylphosphine oxide” (id. at col. 3, ll. 23-24).
3. Watt discloses that the “acetic acid product may be recovered from
the liquid reaction composition by withdrawing vapour and/or liquid from
the carbonylation reactor and recovering acetic acid from the withdrawn
material” (id. at col. 5, ll. 23-26).
4. Watt discloses that the “main liquid by-product from carbonylation
of methanol to acetic acid is propionic acid. It’s [sic] precursors (ethyl
iodide and ethyl acetate) are also formed.” (Id. at col. 6, ll. 15-17.)
5. Carey discloses that a problem associated with acetic acid
produced from
the Group VIII noble metal catalysed, alkyl iodide co-catalysed
carbonylation of alcohols … [is that] the acetic acid and/or
acetic anhydride frequently contains small amounts of iodide
impurities.… [T]hese compounds … probably comprise a
mixture of methyl iodide and other higher alkyl iodides, HI and
iodide salts.
(Id. at col. 2, ll. 30-40.)
6. Carey discloses that these
impurities are particularly troublesome since they can poison
many of the catalysts which are employed in subsequent
chemical conversions of the acetic acid and/or acetic anhydride.
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A case in point is the catalysts used to prepare vinyl acetate
from ethylene and acetic acid which are extremely sensitive to
iodide impurities.
(Id. at col. 2, ll. 41-46.)
7. Carey discloses
a process for removing iodide compounds from a liquid
carboxylic acid and/or carboxylic anhydride obtained from the
Group VIII noble metal catalysed, alkyl iodide co-catalysed
carbonylation of alcohols and/or their reactive derivatives
which process comprises contacting the liquid carboxylic acid
and/or carboxylic acid anhydride with a metal loaded ion-
exchange resin … wherein the metal is one or more of the
metals silver, palladium or mercury.
(Id. at col. 2, ll. 48-56.)
8. Carey discloses that the “ion-exchange resin may be any suitable
resin. It may be, for example, an ion-exchange gel resin, a macroreticular
ion-exchange resin or indeed any other resin which experiences a volume
change upon changing the nature of its solvent environment.” (Id. at col. 1,
ll. 44-47.)
Analysis
Claim 5 is directed to a process for producing acetic acid that
comprises, among other things, (a) reacting methanol and carbon monoxide
in the presence of a carbonylation catalyst, a triphenylphosphine oxide
stabilizer, methyl iodide, water, and methyl acetate to produce an acetic acid
stream containing an iodobenzene compound, (b) flashing part of the acetic
acid stream into a vapor stream and a liquid stream, (c) subjecting the vapor
stream to a distillation to produce an acetic acid stream, and (d) contacting
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the acetic acid stream with palladium supported on a macroreticular ion-
exchange resin to remove iodobenzene.
The Examiner finds, and Appellant does not dispute, that Watt
discloses the claimed process for producing acetic acid, with the exception
that Watt does not disclose the presence of iodobenzene in the acetic acid
product stream or the use of “palladium supported on a macroreticular ion-
exchange resin to remove the iodobenzene.” Since Watt’s carbonylation
reaction includes the same reactants as those required for claim 5, however,
it is reasonable to conclude that iodobenzene is also produced by Watt’s
process, whether or not its presence was recognized or disclosed.
Carey discloses the use of palladium-loaded macroreticular ion-
exchange resin for removing iodide compounds from product streams of
carbonylation reactions. Thus, it would have been obvious to use Carey’s
palladium-loaded macroreticular ion-exchange resin for removing iodide
compounds from an acetic acid product stream produced using Watt’s
process, in order to avoid poisoning catalysts used in subsequent chemical
conversions of the acetic acid. It is reasonable to conclude that using
Carey’s palladium-loaded macroreticular ion-exchange resin to remove
iodide compounds from Watt’s acetic acid product stream would inherently
remove iodobenzene (an iodide compound) from Watt’s acetic acid product
stream.
Appellant argues that the process of claim 5 would not have been
obvious in view of the cited references because Carey only discloses the
removal of C1-C10 alkyl iodides, not iodobenzene (Appeal Br. 3-4).
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This argument is not persuasive. The removal of iodobenzene from
an acetic acid product stream reasonably appears to be the inherent result of
a prior art process. In accordance with In re Woodruff, “discovering and
claiming a new benefit of an old process cannot render the process again
patentable.” 919 F. 2d 1575, 1578 (Fed. Cir. 1990).
Appellant also argues that Carey discloses that “the ion-exchange
resin used for removing alkyl iodide can be any suitable resin … and the
metals can be any metals of Groups I to VIII of the Periodic Table” (Appeal
Br. 3-4).
This argument is also not persuasive. Carey specifically suggests
using a “metal loaded ion exchange resin … wherein the metal is one or
more of the metals silver, palladium or mercury” (FF 7) and the resin is
either an ion-exchange gel resin and a macroreticular ion-exchange resin
(FF 8). Thus, the combination of a macroreticular ion-exchange resin with
palladium would have been an obvious choice from among the limited
preferences expressed by Carey.
Conclusion of Law
The evidence of record supports the Examiner’s conclusion that it
would have obvious to contact an acetic acid product stream from Watt’s
carbonylation process with palladium supported on a macroreticular ion-
exchange resin and thereby remove iodobenzene.
SUMMARY
We affirm the rejection of claims 5-9 under 35 U.S.C. § 103(a).
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TIME PERIOD FOR RESPONSE
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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