Ex Parte Braun et al

Board of Patent Appeals and Interferences

Jan 29, 2003

09113547 (B.P.A.I. Jan. 29, 2003)

The opinion in support of the decision being entered today was
not written for publication and is not binding precedent of the
Board.
Paper No. 31
UNITED STATES PATENT AND TRADEMARK OFFICE
__________
BEFORE THE BOARD OF PATENT APPEALS
AND INTERFERENCES
__________
Ex parte MAX BRAUN, KERSTIN EICHHOLZ and WERNER RUDOLPH
__________
Appeal No. 2002-0440
Application 09/113,547
___________
HEARD: JANUARY 8, 2003
___________
Before WARREN, OWENS and POTEATE, Administrative Patent Judges.
OWENS, Administrative Patent Judge.
DECISION ON APPEAL
This appeal is from the final rejection of claims 1 and 3-9,
which are all of the claims remaining in the application.
Appeal No. 2002-0440
Application 09/113,547

THE INVENTION
The appellants’ claimed invention is directed toward a
method for making a methyl or ethyl ester of trifluoroacetic acid
or chlorodifluoroacetic acid. Claim 1 is illustrative:
1. A method for preparing a methyl or ethyl ester of
trifluoroacetic acid or chlorodifluoroacetic acid, comprising:
reacting an acid chloride of trifluoroacetic acid or
chlorodifluoroacetic acid with a stoichiometric excess of methyl
or ethyl alcohol in the presence of an onium salt of the acid as
catalyst, wherein the molar ratio of alcohol to acid chloride is
selected such that two phases can form;
allowing an upper phase and a lower phase to form, one phase
being an ester phase which contains the ester in a purity,
achievable without a distillation stage, of at least 95% by
weight; and
separating said ester phase.
THE REFERENCES
Feist et al. (Feist) 5,405,991 Apr. 11, 1995
Braun et al. (Braun) 5,532,411 Jul. 2, 1996
THE REJECTION
Claims 1 and 3-9 stand rejected under 35 U.S.C. § 103 as
being unpatentable over Braun in view of Feist.
OPINION
Appeal No. 2002-0440
Application 09/113,547

Braun discloses a method for preparing a carboxylic acid
ester by reacting a carboxylic anhydride with M (Hal ) , where Mn+ - n+n
can be an onium cation and Hal is chloride, bromide or iodide,-
to produce a carboxylic acid halide (which can be the appellants’
acid chloride) and a carboxylate salt (which can be the
appellants’ onium salt), and reacting this product with an
alcohol to form the ester (col. 1, lines 64-65; col. 2, lines 7-
15; col. 3, lines 57-60). The molar ratio of alcohol to
carboxylic acid halide advantageously is between 0.9:1 and 5:1
(col. 5, lines 19-21). The onium salt can be present in a
catalytic amount (col. 5, lines 28-29). Braun teaches that the
method is particularly well suited for preparing esters of
trifluoroacetic acid or chlorodifluoroacetic acid using an
alcohol which can be methanol or ethanol (col. 5, lines 8-13).
Braun does not disclose selecting the molar ratio of alcohol
to acid chloride such that two phases can form, one of which is
an ester phase, and separating the phases. For a suggestion to1
do so the examiner relies upon Feist.
Appeal No. 2002-0440
Application 09/113,547

Feist discloses a method for making a carboxylic ester by
reacting a carboxylic acid bromide or (preferably) a carboxylic
acid chloride with an alcohol in the presence of a catalytic salt
which preferably is an onium salt (col. 2, lines 29-63; col. 3,
lines 62-63; col. 4, lines 10-11). “Advantageously, the molar
ratio of alcohol to carboxylic acid halide is between 0.9:1 and
1.1:1, or if the alcohol also serves as a solvent, up to 5:1"
(col. 3, lines 51-54). Like Braun’s method, Feist’s method is
particularly well suited for preparing esters of trifluoroacetic
acid or chlorodifluoroacetic acid using an alcohol which can be
methanol or ethanol (col. 3, lines 42-46). In Feist’s example 9,
a clear yellow solution containing methyl chlorodifluoroacetate
is produced by reacting 1.0 mole methanol with 1.0 mole
chlorodifluoroacetyl chloride. In Feist’s example 10, ethyl
chlorodifluoroacetate is produced by reacting 1.0 mole ethanol
with 1.0 mole chlorodifluoroacetyl chloride. “After addition of
0.5 mole of the acid chloride, a strong turbidity (phase
formation) was observed in the reaction solution, which upon
Appeal No. 2002-0440
Application 09/113,547

the course of the reaction the formation of two phases was noted”
(col. 6, lines 15-16). “The upper phase contained over 96% of
the desired propyl chlorodifluoroacetate in addition to
pyridinium salts. The lower phase contained the catalyst salt as
its principal component in addition to traces of the product”
(col. 6, lines 19-23). The phases were separated (col. 6,
line 24).
The examiner argues that because phase formation occurred in
Feist’s example 10 at a 2:1 mole ratio of alcohol to acid
chloride during the preparation of ethyl chlorodifluoroacetate,
one of ordinary skill in the art reasonably would have expected
phase formation to take place at that excess alcohol ratio in
Feist’s example 9 during the preparation of methyl
chlorodifluoroacetate (answer, page 5).
Feist adds chlorodifluoroacetyl chloride dropwise to an
alcohol/pyridinium chlorodifluoroacetate mixture in each of
examples 9, 10 and 11. In example 9, wherein the alcohol is
methanol, no phase formation is reported. In example 10, wherein
Appeal No. 2002-0440
Application 09/113,547

alcohol. In example 11, wherein the alcohol is n-propanol, Feist
reports formation of two phases during the course of the
n-propanol/chlorodifluoroacetyl chloride reaction, and Feist
separates the phases. Thus, as the carbon number of the alcohol
goes from 1 to 3, the examples go from 1) no reported phase
formation to 2) “strong turbidity (phase formation)” to
3) formation of two phases followed by separation of the phases.
For a prima facie case of obviousness to be established,
the teachings from the prior art itself must appear to have
suggested the claimed subject matter to one of ordinary skill in
the art. See In re Rinehart, 531 F.2d 1048, 1051, 189 USPQ 143,
147 (CCPA 1976).
The examiner has not provided evidence or technical
reasoning which shows that Feist’s disclosure that “strong
turbidity (phase formation)” occurs at a 2:1 ratio of ethanol to
chlorodifluoroacetyl chloride in example 10, and Feist’s lack of
a similar disclosure in example 9, wherein the alcohol is
methanol, would have led one of ordinary skill in the art to
Appeal No. 2002-0440
Application 09/113,547

Also, the examiner has not provided evidence or technical
reasoning which shows that Feist’s disclosure that there is phase
formation and separation of the phases in example 11 prior to
distillation, wherein the alcohol is n-propanol, but that there
is only “strong turbidity (phase formation)” in example 10,
wherein the alcohol is ethanol and the entire reaction product is
distilled, would have indicated to one of ordinary skill in the
art that the strong turbidity in example 10 is sufficient phase
formation for such a person to separate the phases before
distillation rather than distilling the entire reaction product
as did Feist. Likewise, the examiner has not established that
the teaching of forming “strong turbidity (phase formation)” in
Feist’s example 10 would have led one of ordinary skill in the
art to separate, as argued by the examiner (answer, pages 4-5
and 7), the phases in Braun’s example 11 (which is the same as
Feist’s example 1) wherein the alcohol is 2,2,2-trifluoroethanol.
For the above reasons we conclude that the examiner has not
carried the burden of establishing a prima facie case of
Appeal No. 2002-0440
Application 09/113,547

DECISION
The rejection of claims 1 and 3-9 under 35 U.S.C. § 103 over
Braun in view of Feist is reversed.
REVERSED
)
CHARLES F. WARREN )
Administrative Patent Judge )
)
)
) BOARD OF PATENT
TERRY J. OWENS )
Administrative Patent Judge ) APPEALS AND
)
) INTERFERENCES
)
LINDA R. POTEATE )
Administrative Patent Judge )

TJO/ki
Appeal No. 2002-0440
Application 09/113,547

Crowell & Moring, LLP
P.O. Box 14300
Washington, DC 20044-4300