Ex Parte Dagle et al

Patent Trial and Appeal Board

Jan 30, 2013

11241321 (P.T.A.B. Jan. 30, 2013)

MOD PTOL-90A (Rev.06/08)

APPLICATION NO. FILING DATE FIRST NAMED INVENTOR

ATTORNEY DOCKET NO.
11/241,321 09/30/2005 Robert A. Dagle 14756-e

EXAMINER

Frank S. Roseberg
P.O. Box 29230
San Francisco, CA 94129
KEYS, ROSALYND ANN
ART UNIT PAPER NUMBER
1621
MAIL DATE DELIVERY MODE

01-30-2013 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.

UNITED STATES DEPARTMENT OF COMMERCE
U.S. Patent and Trademark Office
Address : COMMISSIONER FOR PATENTS
P.O. Box 1450
Alexandria, Virginia 22313-1450
www.uspto.gov
UNITED STATES PATENT AND TRADEMARK OFFICE
_____________________________________________________________________________________

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte ROBERT A. DAGLE, YONG WANG,
EDDIE G. BAKER, and JIANLI HU
__________

Appeal 2011-011644
Application 11/241,321
Technology Center 1600
__________

Before TONI R. SCHEINER, DEMETRA J. MILLS, and LORA M. GREEN,
Administrative Patent Judges.

SCHEINER, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal under 35 U.S.C. § 134 from the final rejection of
claims 28-43, 46-49, 51, and 52 directed to a process for producing dimethyl
ether. The claims have been rejected as obvious. We have jurisdiction
under 35 U.S.C. § 6(b).
We affirm.
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STATEMENT OF THE CASE
Claims 28-43, 46-49, 51, and 52 are pending and on appeal. Claims
1-27, 44, 45, and 50 have been canceled (App. Br. 2).
Appellants do not provide separate arguments for the claims with the
exception of 30. Accordingly, we select independent claim 28 and claim 30
as representative for purposes of deciding this appeal, and the remaining
claims will stand or fall accordingly. 37 C.F.R. § 41.37(c)(1)(vii). Claims
28 and 30 are as follows:
28. A process for producing dimethyl ether comprising:
reacting syngas in contact with a hybrid catalyst in a microchannel
reactor at a temperature from about 200º C to about 400º C with a contact
time of from about 25 milliseconds to less than about 1 second; and
converting more than about 60% of CO in the syngas to dimethyl ether and
methanol.
30. The process of claim 28, wherein there is no liquid holdup
inside the microchannel reactor.
The Examiner relies on the following evidence:
Grady et al. US 5,821,111 Oct. 13, 1998
Wegeng et al. US 5,811,062 Sep. 22, 1998
Shikada et al. US 6,562,306 B1 May 13, 2003
Tonkovich et al. US 6,616,909 B1 Sep. 9, 2003
Appellants rely on the following additional evidence:
Declaration of Dr. Anna Lee Tonkovich, submitted under the provisions of
37 C.F.R. § 1.132, dated December 27, 2010 (“Decl.”).
The claims stand rejected under 35 U.S.C. § 103(a) as unpatentable
over Shikada, Tonkovich, Grady, and Wegeng.
ISSUES
The Examiner finds that the Shikada patent discloses a method of
manufacturing dimethyl ether (DME) from syngas (a mixture of carbon
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monoxide and hydrogen, or carbon monoxide, hydrogen, and carbon
dioxide) in a thermal reaction using a hybrid methanol-synthesis, methanol-
dehydration catalyst, wherein the carbon monoxide conversion rate is 35%
or more. The Examiner concedes that the Shikada patent’s reaction
proceeds in a slurry-bed reactor, rather than a microchannel reactor.
However, the Examiner finds that the Tonkovich patent teaches that
performing the reaction in a microchannel reactor provides an “enhanced
production rate of thermal chemical reactions . . . as well as suppress[es] the
formation of undesirable byproducts” (id. at 5-6) in “reactions includ[ing]
dehydration, methanol synthesis and water gas shift” (id. at 6), “which are
the types of reactions that take place in the process taught by Shikada” (id. at
9).
The Examiner concludes that it would have been obvious for one of
ordinary skill in the art to use the Tonkovich patent’s microchannel reactor
to carry out “the thermal chemical reaction of Shikada . . . as this would
allow one to produce the dimethyl ether . . . at an enhanced production rate,
while suppressing undesirable byproducts by using short contact times”
(Ans. 6) of “about 25 milliseconds to less than about 1 second” (id. at 5).
Appellants contend that the Shikada patent teaches that “the reaction
must occur in the slurry phase” (App. Br. 4), and “at the time of the
invention . . . it would not have been known if the slurry phase process of
Shikada could be conducted in a microchannel” (id. at 4-5). Appellants
contend that “there is no reason to have believed that, even if conducted in a
microchannel at the claimed contact times, Shikada’s slurry-phase process
would have succeeded to obtain the claimed levels of conversion” (id. at 5).
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In addition, Appellants contend that “the reaction of syngas to DME
in a microchannel [unexpectedly] results in superior selectivity” (App. Br.
5), “as compared with a conventional slurry bed process” (id.).
The issues raised by this appeal are as follows:
Does the preponderance of the evidence support the Examiner’s
conclusion that it would have been obvious to produce dimethyl ether in a
microchannel reactor, given the teachings of Shikada and Tonkovich?
If so, have Appellants provided evidence of unexpected results that
outweighs the evidence supporting the prima facie case of obviousness?
FINDINGS OF FACT
1. The Shikada patent discloses a method of manufacturing
dimethyl ether from syngas (carbon monoxide and hydrogen) in a slurry bed
reactor, using a variety of hybrid catalysts, including a methanol-synthesis,
methanol-dehydration catalyst (Shikada, col. 7, ll. 61-62; col. 9, ll. 6-35).
The catalysts are in particulate form, and suspended in a solvent for reaction
with the syngas (see e.g., col. 2, l. 34 - col. 3, l. 48).
2. The Shikada patent further teaches that “dimethyl ether
synthesis is a significantly exothermic reaction” (Shikada, col. 53, ll. 33-34).
3. The Tonkovich patent teaches that “the intrinsic kinetics of a
thermal chemical reaction can be much faster than the heat transfer rate
between the reaction vessel and the thermal sink, source or environment,
[thus] the actual rate of product production . . . is slower than the intrinsic
rate” (Tonkovich, col. 1, ll. 29-34), i.e., “the rate at which products could
theoretically be formed at the catalyst surface” (id. at col. 1, ll. 34-36). The
Tonkovich patent teaches that “[l]imited production rates may result from
longer residence time which is typically seconds to minutes in conventional
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thermal chemical reaction vessels” (id. at col. 1, ll. 37-39). Moreover, “[i]n
the case of exothermic reactions, low rates of heat removal may promote
undesired side reactions, or cause thermal hot spots or thermal runaway in
the reactor” (id. at col. 5, ll. 25-27).
4. The Tonkovich patent discloses a microchannel reactor with
multiple reaction chambers, multiple porous catalyst inserts and multiple
heat exchangers (Tonkovich, col. 10, ll. 8-51; Figs. 6, 7) that, unlike
conventional reactors, “permit[s] realization of theoretical or near theoretical
reaction kinetics” for “catalytic thermal chemical reactions” (id. at col. 3, ll.
5-8). The heat exchange capacity of the microchannel reactor is “such that,
at steady state, the catalyst is maintained within a temperature range that
reduces the formation of at least one undesirable chemical reaction product”
(id. at col. 4, ll. 15-18). In addition, the heat exchange capacity of the
microchannel reactor permits a contact time of less than about 0.3 seconds,
thereby reducing the formation of undesirable chemical products that “can
result from secondary reactions or slow parallel reactions” (id. at col. 4, ll.
18-23).
5. The Tonkovich patent teaches that the microchannel reactor is
suitable for methanol synthesis reactions, dehydration reactions, etc., using
hybrid catalysts (Tonkovich, col. 11, ll. 12-30). These are the same types of
reactions and catalysts involved in the Shikada patent’s DME synthesis, but
in this case, the hybrid catalyst is not in the form of particles suspended in a
slurry. Rather, in the Tonkovich patent, “a preferred catalyst has a porous
support, a solution deposited interfacial layer thereon, and a catalyst material
on the interfacial layer” (Tonkovich, col. 5, l. 66 - col. 6, l. 1; compare FF1).
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6. According to the Declaration of Dr. Anna Tonkovich, the
Examples and Table 2 of the Specification “show improved results for the
synthesis of DME including substantially improved selectivity to the desired
product (as shown as lower selectivity to the undesired carbon dioxide) as
compared to a conventional slurry process” (Decl. ¶ 5). Dr. Tonkovich
declares that “this is a surprising and superior result for the [claimed process
. . . as compared to a slurry process such as in the [Shikada] '306 patent”
(id.). Dr. Tonkovich further declares that she “do[es] not believe that the
[Tonkovich] '909 patent predicts substantially improved selectivity as
compared to a slurry phase process because a slurry process is well known
as a means for limiting reaction isotherms and should be quite isothermal”
(id.).
7. Table 2 of the Specification is as follows:

(Specification, Table 2.)
8. Wegeng teaches that a “microchannel reactor is preferably used
for reactions that do not require materials or solid that would clog the
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microchannels and that do not produce material or solids that would clog the
microchannels” (Wegeng, col. 10, ll. 31-34).
DISCUSSION
We agree with the Examiner’s rationale and conclusion that it would
have been obvious to produce dimethyl ether in a microchannel reactor,
given the teachings of the prior art.
We are not persuaded otherwise by Appellants’ contention that the
Shikada patent’s production of dimethyl ether “must occur in the slurry
phase” (App. Br. 4), and “there is no suggestion in any of the cited
references that Shikada’s slurry phase process would have had a reasonable
expectation of success when carried out at short contact times in a
microchannel reactor” (id. at 5). As discussed above, the Tonkovich patent
teaches that the microchannel reactor is suitable for methanol synthesis and
dehydration, the same types of exothermic reactions, using the same types of
hybrid catalysts, as in the Shikada patent’s reactions, but on catalyst-coated
porous solid supports, rather than in a slurry phase (FFs 1, 4, 5).
To the extent Appellants contend that “there is no reason to have
believed that, even if conducted in a microchannel at the claimed contact
times, Shikada’s slurry-phase process would have succeeded to obtain the
claimed levels of conversion” (App. Br. 5), we disagree. The Tonkovich
patent teaches that the use of the microchannel reactor allows production at
near theoretical reaction kinetics (FF4), and Appellants have not explained
why one would not have expected optimal conversion of carbon monoxide
under such conditions.
Appellants further contend that “[n]one of the cited references
describe[s] a technique for carrying out a slurry phase process in a
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microchannel” (App. Br. 5). Appellants contend that Wegeng “teach[es]
away from reactions such as slurry phase processes that would contain solid
particles that could clog a microchannel” (id.).
This argument is not persuasive. Wegeng teaches that microchannel
reactors are appropriate for reactions that don’t involve materials or solids
that would clog the microchannels and that don’t produce material or solids
that would clog the microchannels (FF8). The Examiner concludes that it
would have been obvious to carry out a DME synthesis reaction in a
microchannel reactor, not that it would have been obvious to carry out a
slurry phase process in a microchannel reactor. One of ordinary skill in the
art would understand that Shikada’s solvent suspended catalyst particles
would not be used in a microchannel reactor like that disclosed in the
Tonkovich patent. The catalysts in a microchannel reactor are coated onto
porous supports that are inserted in the reactor in the path of the reactants -
carbon monoxide and hydrogen, in the case of DME synthesis from syngas
(FFs 1, 4, 5). Appellants have not established that materials or solids that
could clog the microchannel reactor are formed during DME synthesis from
syngas.
Finally, Appellants argue that the use of the microchannel reactor
provides a surprising and unexpected degree of selectivity as compared to a
conventional slurry process (App. Br. 5; Decl. ¶ 5), and moreover, this
improved selectivity is also unexpected in view of the Tonkovich patent
because “a slurry process is well known as a means for limiting reaction
exotherms and should be quite isothermal” (Decl. ¶ 5; FF6).
This argument is not persuasive. Contact time is also a factor in
selectivity, and the Tonkovich patent explains that the shorter reaction time
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made possible by the microchannel reactor suppresses undesirable products
of secondary reactions or slow parallel reactions (FF4). Therefore, we agree
with the Examiner that the results shown in the Examples and Table 2 of the
Specification, and discussed in Dr. Tonkovich’s declaration would not have
been unexpected, given the teachings of the Tonkovich patent.
CONCLUSION
The evidence of record supports the Examiner’s conclusion that it
would have been obvious for one of ordinary skill in the art to produce
dimethyl ether in a microchannel reactor, given the teachings of the prior art
relied on. Appellants have not provided evidence of unexpected results
sufficient to outweigh the evidence supporting the prima facie case of
obviousness.
Accordingly, we affirm the rejection of claims 28 and 30 as
unpatentable over Shikada, Tonkovich, Grady, and Wegeng. Claims 29, 31-
43, 46-49, 51, and 52 have not been argued separately and therefore fall with
claim 28. 37 C.F.R. § 41.37(c)(1)(vii).
SUMMARY
The rejection of claims 28-43, 46-49, 51, and 52 under 35 U.S.C.
§ 103(a) is affirmed.

Appeal 2011-011644
Application 11/241,321

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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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