Ex Parte Ackermann et al

Patent Trial and Appeal Board

Sep 12, 2013

11914493 (P.T.A.B. Sep. 12, 2013)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte JOCHEN ACKERMANN,
ALEXANDER MAY, UDO GROPP, HERMANN SIEGERT,
BERND VOGEL, and SOENKE BROECKER
__________

Appeal 2012-001782
Application 11/914,493
Technology Center 1600
__________

Before TONI R. SCHEINER, FRANCISCO C. PRATS, and
SUSAN L.C. MITCHELL, Administrative Patent Judges.

PRATS, Administrative Patent Judge.

DECISION ON APPEAL
This appeal1 under 35 U.S.C. § 134 involves claims to processes of
preparing esters of methacrylic acid by transesterification. The Examiner
rejected the claims as obvious.
We have jurisdiction under 35 U.S.C. § 6(b).
We affirm.

1 Appellants identify the Real Party in Interest as Evonik Roehm GmbH,
Darmstadt, Germany (App. Br. 1).
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STATEMENT OF THE CASE
Claims 1-3, 6, 7, 9-12, and 17 stand rejected and appealed (App. Br.
2). Because Appellants do not argue any of the claims separately, the claims
stand or fall together. See 37 C.F.R. § 41.37(c)(1)(vii).
Claim 1 is representative and read as follows:
A process for transesterification comprising:
A) mixing methacrylic acid with at least one ester; and
B) transferring an alcohol radical of the at least one ester to the
methacrylic acid to obtain an ester of methacrylic acid and an acid of
the at least one ester;
wherein:
B) is carried out in an apparatus comprising at least one
distillation column and at least one reactor;
the at least one ester comprises an alkyl α-hydroxycarboxylate;
and
the reaction mixture comprises at least one polymerization
inhibitor selected from the group consisting of phenothiazine,
tert-butylcatechol, hydroquinone monomethyl ether, hydroquinone,
and 4-hydroxy-2,2,6,6-tetramethylpiperidinooxyl.

The sole rejection before us for review is the Examiner’s rejection of
claims 1-3, 6, 7, 9-12, and 17 under 35 U.S.C. § 103(a) as obvious over
Imperial2 and Hardman3 (Ans. 4-12).
DISCUSSION
The Examiner found that Imperial described a transesterification
process which exemplified the use of ethyl lactate, an alkyl
α-hydroxycarboxylate as required by Appellants’ claim 1, as an alcohol-
donating ester (see Ans. 5-6). The Examiner noted, and Appellants do not

2 Imperial Chemical Industries, (hereinafter “Imperial”), GB 34l 730A
(published Jan. 22, 1931).
3 Hardman et al., U.S. Patent No. 4,458,088 (issued Jul. 3, 1984).
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dispute, that Imperial’s reaction was performed in an apparatus including at
least one distillation column and at least one reactor, as Appellants’ claim 1
also requires (see id. at 6).
The Examiner conceded, however, that Imperial “fails to teach a
methacrylic acid” as the alcohol group acceptor, as claim 1 further requires
(id. at 8). To address that deficiency, the Examiner cited Hardman as
disclosing methacrylic acid as an alcohol acceptor in a transesterification
process that also used a reactor and a distillation column (see id.). The
Examiner noted that Hardman’s process used polymerization inhibitors,
including phenothiazine, as recited in claim 1 (see id. at 9).
The Examiner urged that claim 1 would have been obvious to an
ordinary artisan based on two rationales: “[t]he first is that it would have
been obvious to substitute one known reactant in a process for another, and
the second [is] that there is a teaching suggestion, motivation to combine the
teachings of the references” (id.).
The Examiner first contended that, because both Imperial and
Hardman taught transesterification processes, and because Imperial
suggested that its process could use a “broader range of carboxylic acids” as
alcohol acceptors beyond those expressly described in the reference, “one
skilled in the art could have substituted one known element for another
element known in the art and the substitution would have yielded nothing
more than predictable results to one of ordinary skill in the art at the time of
invention” (id. at 10).
The Examiner further contended that it would have been obvious to
combine the teachings of the two references because “one would want to
minimize waste in the process and [Hardman] teaches that reagents can be
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recycled. Thus, one skilled in the art would want to reduce cost, and
minimize environmental burden by recycling reagents” (id.).
As stated in In re Oetiker, 977 F.2d 1443, 1445 (Fed. Cir. 1992):
[T]he examiner bears the initial burden . . . of presenting a
prima facie case of unpatentability. . . .
After evidence or argument is submitted by the applicant
in response, patentability is determined on the totality of the
record, by a preponderance of evidence with due consideration
to persuasiveness of argument.

Appellants’ arguments do not persuade us that a preponderance of the
evidence fails to support the Examiner’s conclusion of obviousness as to
claim 1.
Claim 1 recites a transesterification process in which methacrylic acid
and at least one ester are mixed together as the initial reactants. The mixing
must be performed under conditions that result in transfer of an alcohol
radical from the initial reactant ester to the methacrylic acid, ultimately
producing an ester of methacrylic acid, as well as resulting in conversion of
the initial reactant ester to an acid.
Claim 1 requires the alcohol transfer to be performed in an apparatus
that has at least one distillation column and at least one reactor. Claim 1
requires the initial reactant ester to include an alkyl α-hydroxycarboxylate.
Claim 1 further requires the reaction mixture to include at least one
polymerization inhibitor which can be phenothiazine, among other
compounds.
As the Examiner found, Imperial describes a transesterification
process which uses ethyl lactate, an ester which is undisputedly an alkyl
α-hydroxycarboxylate encompassed by claim 1, as an alcohol donor to acetic
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acid, to produce ethyl acetate and lactic acid (see Imperial p. 1, ll. 64-74).
Appellants do not dispute the Examiner’s characterization of Imperial as
using a reactor and distillation column in its process, as claim 1 requires.
While Imperial does not describe methacrylic acid as an alcohol group
acceptor, as the Examiner found, Imperial explicitly states that its method
has broader applicability to carboxylic acids beyond those exemplified:
Although the above examples are limited to reactions
between ethyl acetate and formic acid, ethyl propionate and
acetic acid, ethyl lactate and acetic acid, and diethyl carbonate
and acetic acid, our invention is of general application for the
interchange between alkyl esters of carboxylic acids and
carboxylic acids, and includes reactions at room temperature
as well as those in which heat is applied.

(Id. at p. 1, ll. 83-92 (emphasis added).)
Moreover, as the Examiner further found, Hardman discloses that it
was desirable to produce alkyl esters of methacrylic acid, including ethyl
esters, by a transesterification process (see Hardman, col. 7, ll. 50-63; see
also id. at col. 3, l. 30, through col. 4, l. 6 (describing general reaction
scheme)). As the Examiner noted, Hardman’s process includes product
removal by distillation so as to drive the reaction equilibrium toward product
formation (see id. at col. 4, ll. 4-14). As the Examiner further noted,
Hardman describes using a polymerization inhibitor, such as phenothiazine,
in the reaction to prevent polymerization of the acid (see id. at col. 6, ll. 7-
20).
Because, as taught in Imperial, ethyl lactate was known in the prior art
to be a suitable alcohol donor to a variety of carboxylic acids in
transesterification reactions, and because, as taught in Hardman, it was
known to be desirable to prepare ethyl esters of methacrylic acid by
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transesterification reactions, we agree with the Examiner that an ordinary
artisan would have been prompted to mix methacrylic acid and ethyl lactate
and thereby transfer the ethyl alcohol moiety from the lactic acid ester to the
methacrylic acid to produce the methacrylic acid ethyl ester, resulting in the
transfer reaction required by claim 1. Given Hardman’s teaching of
including phenothiazine in the reaction mixture to avoid polymerization, we
further agree that it would have been obvious to include phenothiazine in the
reaction, as claim 1 also requires.
Thus, as the rationale for combining the references’ teachings would
have been derived from the disclosures of references as discussed above, we
are not persuaded that an ordinary artisan lacked a reason to combine the
references’ teachings in the manner posited, nor are we persuaded that the
artisan would have arrived at the claimed process only through improper
hindsight, as Appellants argue (see App. Br. 6-7; see also Reply Br. 2-3).
We note Appellants’ argument regarding the differences between the
acetic acid alcohol acceptor in Imperial, which is not unsaturated, and the
fact that Hardman’s methacrylic acid is unsaturated (see App. Br. 6-7; see
also Reply Br. 2). While these facts may demonstrate that the processes of
Imperial and Hardman are different from the claimed process, as the
Supreme Court has pointed out, “the mere existence of differences between
the prior art and an invention does not establish the invention’s
nonobviousness.” Dann v. Johnston, 425 U.S. 219, 230 (1976).
Moreover, Appellants direct us to no clear or specific evidence in the
cited references suggesting that an ordinary artisan would have expected
ethyl lactate and methacrylic acid to be incompatible transesterification
partners. To the contrary, as noted above, Imperial expressly states that
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ethyl lactate can be partnered with other carboxylic acids, and Hardman
discloses the suitability of methacrylic acid as an ethyl alcohol acceptor in
transesterification reactions. Appellants’ arguments (see Reply Br. 2) do
not, therefore, persuade us that the cited references would have failed to
provide a reasonable expectation of success in partnering ethyl lactate and
methacrylic acid in a transesterification reaction.
Regarding Appellants’ argument that the claimed process produces
results superior to prior art processes, as our reviewing court has pointed out,
“[m]ere improvement in properties does not always suffice to show
unexpected results. . . . [W]hen an applicant demonstrates substantially
improved results . . . and states that the results were unexpected, this should
suffice to establish unexpected results in the absence of evidence to the
contrary.” In re Soni, 54 F.3d 746, 751 (Fed. Cir. 1995).
Moreover, “when unexpected results are used as evidence of
nonobviousness, the results must be shown to be unexpected compared with
the closest prior art.” In re Baxter-Travenol Labs., 952 F.2d 388, 392 (Fed.
Cir. 1991).
Thus, we acknowledge Appellants’ argument that the claimed process
includes advantages with respect to simplicity, cost (including low energy
demand), low by-product formation, high reaction selectivity, high yield,
and execution on an industrial scale (see App. Br. 5-6 (citing Spec. 1-2); see
also Reply Br. 1-2). We also acknowledge the data presented in the
Specification regarding the selectivity of reactions encompassed by claim 1
(see Spec. 15-18).
However, Appellants do not direct us, in either the Appeal Brief or the
Reply Brief, to any clear or specific direct comparison between a process
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encompassed by claim 1 and a close prior art process, for example a process
as described in either Imperial or Hardman. Nor have Appellants directed us
to any clear or specific statement, in either the Appeal Brief, Reply Brief,
Specification, or elsewhere in the record, suggesting that, based on such a
comparison, the asserted improvements in cost, yield, selectivity, etc., were
substantial to such an extent that an ordinary artisan would have considered
them unexpected.
Thus, for the foregoing reasons, Appellants’ arguments do not
persuade us that the Examiner failed to make out a prima facie case of
obviousness as to claim 1, nor are we persuaded that the Examiner erred in
finding that Appellants’ evidence of secondary considerations was not
sufficient to outweigh the evidence of prima facie obviousness.
We therefore affirm the Examiner’s rejection of claim 1 as obvious
over Imperial and Hardman, and the remaining claims fall with claim 1. See
37 C.F.R. § 41.37(c)(1)(vii).

TIME PERIOD
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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