Ex Parte Mitschke et al

Patent Trial and Appeal Board

Mar 28, 2017

13509832 (P.T.A.B. Mar. 28, 2017)

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.
13/509,832 05/15/2012 Peter Mitschke 812822 1068
95683 7590 03/30/2017
Leydig, Voit & Mayer, Ltd. (Frankfurt office)
Two Prudential Plaza, Suite 4900
180 North Stetson Avenue
Chicago, IL 60601-6731
EXAMINER
KEYS, ROSALYND ANN
ART UNIT PAPER NUMBER
1671
NOTIFICATION DATE DELIVERY MODE
03/30/2017 ELECTRONIC
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.
Notice of the Office communication was sent electronically on above-indicated "Notification Date" to the
following e-mail address(es):
chgpatent @ ley dig. com
PTOL-90A (Rev. 04/07)
UNITED STATES PATENT AND TRADEMARK OFFICE
BEFORE THE PATENT TRIAL AND APPEAL BOARD
Ex parte PETER MITSCHKE, ECKHARD SEIDEL,
THOMAS RENNER, and MARTIN ROTHAEMEL
Appeal 2016-001934
Application 13/509,832
Technology Center 1600
Before JEFFREY N. FREDMAN, RYAN H. FLAX, and
RACHEL H. TOWNSEND, Administrative Patent Judges.
FREDMAN, Administrative Patent Judge.
DECISION ON APPEAL
This is an appeal1 under 35U.S.C. § 134 involving a method of
producing dimethyl ether by catalytic dehydration of crude methanol. The
Examiner rejected the claims as obvious. We have jurisdiction under
35 U.S.C. § 6(b). We affirm.
Statement of the Case
Background
“The catalytic production of dimethyl ether (DME) from methanol by
catalytic dehydration is known for many years” (Spec. 13). “[Cjurrent
1 Appellants identify the Real Party in Interest as AIR LIQUIDE
GLOBAL E&C SOLUTIONS GERMANY GMBH (see App. Br. 1).
Appeal 2016-001934
Application 13/509,832
industrial practice consists in [sic] using pure methanol for producing
DME,” but “production of pure methanol from crude methanol involves a
great expenditure of both apparatus and energy .... Therefore, the demand
exists for quite some time to provide a practically useful process for
producing DME proceeding from crude methanol” (Spec. ^fl[ 5, 7).
The Claims
Claims 15—30 and 34 are on appeal. Claim 15 is representative and
reads as follows (emphasis added):
15. A method of producing dimethyl ether by catalytic
dehydration of crude methanol as feedstock in the gas phase,
the method comprising:
(a) providing crude methanol from methanol synthesis,
the crude methanol having a total content of carbonyl
compounds of not more than 100 wt-ppm. calculated as mass
equivalents of acetone;
(b) evaporating the crude methanol and adjusting a
reaction temperature and a reaction pressure;
(c) charging a reactor filled with dehydration catalyst
with the evaporated crude methanol with a defined space
velocity;
(d) discharging a gaseous product mixture comprising
dimethyl ether, non-reacted methanol and water; and
(e) cooling, partially condensing, and separating the
gaseous product mixture so as to provide gaseous dimethyl
ether, liquid water, and methanol as products, and recirculating
the methanol product to step (a).
The Issues
A. The Examiner rejected claims 15—22, 25—27, and 34 under 35 U.S.C.
§ 103(a) as obvious over Murai2 and Emil Supp3 (Ans. 3 4).
2 Murai et al., US 4,560,807, issued Dec. 24, 1985 (“Murai”).
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Application 13/509,832
B. The Examiner rejected claims 23, 24, and 29 under 35 U.S.C. § 103(a)
as obvious over Murai, Emil Supp, and Jun3 4 (Ans. 4—5, 6).
C. The Examiner rejected claim 28 under 35 U.S.C. § 103(a) as obvious
over Murai, Emil Supp, and Olah5 (Ans. 5).
A. 35 U.S.C. § 103(a) over Murai and Emil Supp
The Examiner finds Murai teaches
preparation of dimethyl ether comprising dehydration of
methanol wherein the methanol that is provided includes
methanol that may not necessarily be highly pure and may be
selected from a wide range of material sources as well as
methanol that is recovered from the dehydration process and
recycled in a pure state
(Ans. 3). The Examiner acknowledges that “although Murai et al. disclose
that one can use synthetic methanol and methanol that is not necessarily
highly pure, Murai et al. do not disclose the carbonyl content of the
methanol” (Ans. 4).
The Examiner finds Emil Supp teaches “a typical crude methanol
composition comprises 1 ppm wt. acetone and 820 ppm wt. methyl formate .
... It is further disclosed that methyl formate is the second key component
and acetone occurs in raw methanol in the order of a few ppm” (Ans. 4).
3 Emil Supp, How to Produce Methanol from Coal, 120, 134 (1990)
(“Emil Supp”).
4 Jun et al., US 6,740,783 Bl, issued May 25, 2004 (“Jun”).
5 Olah et al., WO 2006/113293 Al, published Oct. 26, 2006 (“Olah”).
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Application 13/509,832
The Examiner finds it obvious
that the synthetic methanol of Murai et al. comprises between 1
ppm wt. and a few ppm wt. acetone and 820 ppm wt. methyl
formate, since Emil Supp discloses that a typical crude
methanol composition comprises 1 ppm wt. acetone and 820
ppm wt. methyl formate . . . and that methyl formate is the
second key component and acetone occurs in raw methanol in
the order of a few ppm.
(Ans. 4).
The issues with respect to this rejection are:
(i) Does the evidence of record support the Examiner’s conclusion
that Murai and Emil Supp render obvious dimethyl ether production process
using a “crude methanol having a total content of carbonyl compounds of
not more than 100 wt-ppm” as required by claim 15?
(ii) If so, have Appellants presented evidence of secondary
considerations, that when weighed with the evidence of obviousness, is
sufficient to support a conclusion of non-obviousness?
Findings of Fact
1. Murai teaches “a process for producing dimethyl ether in high
purity which is extremely useful as a propellant, by efficiently separating the
reaction mixture from the vapour phase dehydration reaction of methanol
and recycling unreacted methanol to use it as the starting material” (Murai
1:7-12).
2. Murai teaches
as the recovered unreacted methanol is recycled and reused,
impurities having boiling points in between dimethyl ether and
methanol. . . gradually accumulate, and it has been found also
that the accumulation of the impurities can reach a level as high
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Application 13/509,832
as 20% or higher .... Thus, inclusion of impurities in the
dimethyl ether product is unavoidable. When this dimethyl
ether product is to be used as a propellant, it has a fatal defect
as an aerosol product in that it gives rise to an odor.
(Murai 1:66 to 2:12).
3. Murai teaches
by combining a pressurized reaction method with a specific two
step distillation process, it is possible to realize superior
reaction performance and highly efficient separation and
purification, whereby highly pure dimethyl ether can be
produced in an industrially extremely advantageous manner,
and at the same time, it is possible to recover unreacted
methanol in a pure state and recycle it to use it again as the
starting material.
(Murai 2:25—33).
4. Murai teaches “almost pure unreacted methanol is distilled as a
side stream and recovered via a methanol condenser 16 into a recovery
methanol tank 17” (Murai 4:67 to 5:2).
5. Murai teaches “by-product methanol containing substantial
amount of impurities, generated e.g. at the time of the production of a
polyester, may be employed, since byproducts attributable to such impurities
can be readily separated from dimethyl ether and the recovered methanol”
(Murai 5:32—36).
6. Table 4.1 of Emil Supp is reproduced, in part, below:
liable 4.1. Requirements for grade A and grade AA raesbanei
Characteristics Grade A Grade AA
Acetone & Aldehydes
% by wt. ssax. 0.003 0*003
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Application 13/509,832
“[P]ure methanol of a quality as defined by US Federal Grade Specification
O-M 232 which in its revision of June 5, 1975 still defines even today which
imuprities pure methanol may contain. Two different qualities — Grade A
and Grade AA — are listed in Table 4.1” (Emil Supp 134).
7. Table 3.7 of Emil Supp is reproduced below:
IfcMe 3.7. Topical erode methanol composition
Methanol
Mater
92.S3 % wt,
5.55 % wt.
Dissolved Oases
GO?
CO
ch4
Mg 4 Ar
1.05 % wt.
0.10 % wt.
0.05 X wt.
0.04 t wt.
0.35 % wt.
Light Ends
Dimethylether + C§ Hydrocarbons
Acetone
Methylforalate
Others
200 ppm wt.
1 ppm wt.
820 ppm wt.
30 ppm wt.
Heavy Ends
Cg - Cjq Hydrocarbons
Ethanol
Cj - Cg Alcohols
Others
30 ppm wt.
1200 ppm wt.
1000 ppm wt.
50 ppm wt.
“Table 3.7 shows a typical crude methanol composition as can be expected
on a catalyst with good selectivity” (Emil Supp 120).
Principles of Law
“An essential purpose of patent examination is to fashion claims that
are precise, clear, correct, and unambiguous. Only in this way can
uncertainties of claim scope be removed, as much as possible, during the
administrative process.” In re Zletz, 893 F.2d 319, 322 (Fed. Cir. 1989).
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Application 13/509,832
Analysis
Prima facie obviousness
We begin with claim interpretation, since before a claim is properly
interpreted, its scope cannot be compared to the prior art. The specific
phrase at issue in claim 15 is “crude methanol.”
The Specification teaches that: “Pure methanol here is understood to
be a purified, largely anhydrous product of methanol synthesis” while the
“direct product of methanol synthesis, on the other hand, is referred to as
crude methanol and beside several wt-% of water also contains higher
alcohols, ethers, esters, ketones, aldehydes, hydrocarbons and dissolved
synthesis gas constituents each in trace amounts” (Spec. 1 5; emphasis
added).
However, the Specification also teaches that “[occasionally, there is
also initially effected a distillative partial separation of water, wherein the
methanol product obtained also is still referred to as crude methanol” (Spec.
| 6).6 The Specification teaches that in order to obtain “crude methanol”
with less than 100 ppm carbonyl compounds,
the distillative separation of the crude methanol is effected,
wherein the components with boiling points below that of the
methanol are separated as top product. The stabilized crude
methanol obtained as bottom product is supplied to an
intermediate container. The water content of the stabilized
6 We recognize that the ordinary meaning of the term “crude” is “existing in
a natural state and unaltered by cooking or processing” (see
https://www.merriam-webster.com/dictionary/crude, accessed Feb. 3, 2017),
but “a patentee may choose to be his own lexicographer ... as long as the
special definition of the term is clearly stated in the patent specification”.
Vitronics Corp. v. Conceptronic, Inc., 90 F.3d 1576, 1582 (Fed. Cir. 1996).
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Application 13/509,832
crude methanol is 12 wt-%, its total content of carbonyl
compounds is about 50 wt-ppm, calculated as acetone, and the
acetone content is about 30 wt-ppm. The crude methanol is
withdrawn from the intermediate container by means of a
pump.
(Spec. 128).
Thus, the Specification also refers to methanol that has undergone
distillative separation as “crude methanol” and using that distilled methanol,
the Specification teaches that “a partial conversion of the crude methanol to
DME and water is effected” (Spec. 128).
Thus, the Specification recognizes at least two different “crude
methanol” preparations: a first preparation that is the direct product of
methanol synthesis and may contain any amount of carbonyl compounds
(see Spec. 1 5); and a second preparation that was subject to distillative
separation and contains less than 100 ppm carbonyl compounds (see Spec.
128). Consistent with the usage in the Specification, we therefore interpret
the term “crude methanol” as encompassing either preparation.
Murai teaches a method of producing dimethyl ether (FF 1) where
unreacted methanol is captured, distilled, and recycled for use in a
subsequent production of dimethyl ether (FF 2—3). Murai teaches recycled
methanol contains impurities (FF 5). Murai teaches that impurities are
undesirable (FF 2) and therefore distills the methanol until it is “almost
pure” (FF 4).
We recognize, but find unpersuasive, Appellants’ contention that
“Murai suggests certain purification techniques in obtaining its DME, but
nowhere recognizes an advantage in limiting the amount of carbonyl
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Application 13/509,832
compounds, as recited in independent claims 15 and 34. Nor does [Emil]
Supp teach or suggest any benefit in limiting carbonyl compounds” (App.
Br. 4).
While Murai does not provide specific details regarding the carbonyl
content of the distilled methanol, Murai does teach use of the “almost pure”
methanol results in pure dimethyl ether (FF 4), while “crude” unpurified
methanol results in dimethyl ether with an “odor” (FF 2).
Given the overlapping steps shared by the distillation process of
producing methanol taught by Murai and the distillation process in the
Specification that resulted in “crude methanol” with less than 100 ppm
carbonyl compounds, the Examiner reasonably finds “the ordinary skilled
artisan would reasonably expect substantially pure methanol to contain a
carbonyl compound content somewhere between pure methanol and crude
methanol” (Ans. 8).
We recognize, but find unpersuasive, Appellants’ contention that
“Murai does not indicate which compound(s) should be removed from crude
methanol. Col. 5,11. 31-40. Murai instead uses pressure and distillation to
address known problems using recycle methanol of unknown quality in
DME synthesis” (App. Br. 5).
However, because Murai and the Specification both use distillation
processes to obtain methanol, and the Specification teaches that distillation
results in methanol with less than 100 ppm carbonyl compounds, and
because the Specification demonstrates that the metes and bounds of “crude
methanol” are very broad (see Spec. ]Hf 5, 28), we think the burden of
demonstrating that the “almost pure” methanol of Murai does not satisfy the
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Application 13/509,832
requirements of claim 15 is properly placed on Appellants. See In re Best,
562 F.2d 1252, 1255 (CCPA 1977) (“Where, as here, the claimed and prior
art products are identical or substantially identical, or are produced by
identical or substantially identical processes, the PTO can require an
applicant to prove that the prior art products do not necessarily or inherently
possess the characteristics of his claimed product.”).
Appellants provide no evidence that Murai’s distilled methanol fails
to satisfy the requirement for having less than 100 ppm carbonyl
compounds. The Examiner cites Emil Supp to demonstrate that while
“crude” methanol has around 820 ppm carbonyl compounds (FF 7),
methanol subjected to purification processes results in about 0.003% (i.e. 30
ppm) carbonyl compound (FF 6) and the Specification also teaches that
methanol subject to distillation processes results in less than 100 ppm
carbonyl compounds (Spec. 128).
Secondary Considerations
Appellants contend “the present specification demonstrates
unexpected and superior results for using crude methanol with the carbonyl
compound characteristics recited in the claims. Namely, the present
application shows that using crude methanol, but limiting its carbonyl
content, surprisingly] avoids by-product and build-up problems” (App. Br.
5—6). In particular, Appellants contend:
Example 7 shows that undesired side reactions, taking place at
excessive acetone concentrations in the crude methanol,
distinctly decreased the BET surface and the pore volume of the
catalyst. | [0036]. Examples 5 and 6 show 100 unknown
byproducts for 2000 ppm of MEK, but no such complications
for crude methanol containing 1000 ppm ethanol, 280 ppm
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Application 13/509,832
isopropanol, 280 ppm sec-butanol, and 200 ppm hexane.
[0032] though [0035]. Moreover, crude methanols with 100
wt-ppm or less of acetone (1 [0030]) or 60 wt-ppm MEK
(1 [0034]), both carbonyl compounds, surprisingly avoids these
problems.
(App. Br. 6). Appellants contend: “Nor, as the Office suggests ... is there
any requirement that the evidence provided in the specification ‘compare the
closest prior art’ to establish unexpected results” (App. Br. 7).
We do not find this argument persuasive. While it is certainly true
that the Specification need not provide a comparison to the closest prior art,
when relying on comparative tests to rebut a prima facie case of
obviousness, there is a requirement to compare the asserted results with the
closest prior art to demonstrate that the result is unexpected. “Moreover, an
applicant relying on comparative tests to rebut a prima facie case of
obviousness must compare his claimed invention to the closest prior art.” In
re De Blauwe, 736 F.2d 699, 705 (Fed. Cir. 1984).
In this case, the asserted unexpected results were not compared with
the closest prior art of Murai. See In re Baxter Travenol Labs., 952 F.2d
388, 392 (Fed. Cir. 1991) (“when unexpected results are used as evidence of
nonobviousness, the results must be shown to be unexpected compared with
the closest prior art.”). Nor do Appellants explain whether the results of
Example 6 include the impurities relevant in Murai or whether the impurities
present were other components present in neither Murai nor the claimed
“crude methanol.”
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Application 13/509,832
Conclusion of Law
(i) The evidence of record supports the Examiner’s conclusion that
Murai and Emil Supp render obvious dimethyl ether production process
using a “crude methanol having a total content of carbonyl compounds of
not more than 100 wt-ppm” as required by claim 15.
(ii) Appellants have not presented evidence of secondary
considerations, that when weighed with the evidence of obviousness, is
sufficient to support a conclusion of non-obviousness.
B.-C. 35 U.S.C. § 103(a)
Appellants do not separately argue the rejections further relying upon
Jun and Olah. Having affirmed the rejection of claim 15 over Murai and
Emil Supp for the reasons given above, we also affirm the further rejections
over Jun and Olah for the reasons given by the Examiner (see Ans. 4—6).
SUMMARY
In summary, we affirm the rejection of claim 15 under 35 U.S.C.
§ 103(a) as obvious over Murai and Emil Supp. Claims 16—22, 25—27, and
34 fall with claim 15.
We affirm the rejection of claims 23, 24, and 29 under 35 U.S.C.
§ 103(a) as obvious over Murai, Emil Supp, and Jun.
We affirm the rejection of claim 28 under 35 U.S.C. § 103(a) as
obvious over Murai, Emil Supp, and Olah.
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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