Jan Van Krieken et al.

Patent Trials and Appeals Board

Sep 19, 2019

14767004 - (D) (P.T.A.B. Sep. 19, 2019)

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.
14/767,004 08/11/2015 Jan VAN KRIEKEN 166970 4764
25944 7590 09/19/2019
OLIFF PLC
P.O. BOX 320850
ALEXANDRIA, VA 22320-4850
EXAMINER
MARTIN, PAUL C
ART UNIT PAPER NUMBER
1653
NOTIFICATION DATE DELIVERY MODE
09/19/2019 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):
OfficeAction25944@oliff.com
jarmstrong@oliff.com
PTOL-90A (Rev. 04/07)

UNITED STATES PATENT AND TRADEMARK OFFICE
__________

BEFORE THE PATENT TRIAL AND APPEAL BOARD
__________

Ex parte JAN VAN KRIEKEN,
ANDRÉ BANIER DE HAAN, and JAN VAN BREUGEL
__________

Appeal 2018-006911
Application 14/767,004
Technology Center 1600
__________

Before ERIC B. GRIMES, JEFFREY N. FREDMAN, and
ULRIKE W. JENKS, Administrative Patent Judges.

FREDMAN, Administrative Patent Judge.

DECISION ON APPEAL
This is an appeal1,2 under 35 U.S.C. § 134 involving claims to a
process for preparing methyl lactate. The Examiner rejected the claims as
obvious. We have jurisdiction under 35 U.S.C. § 6(b). We reverse.

1 We use the word “Appellant” to refer to “applicant” as defined in 37
C.F.R. § 1.42. Appellant identifies the Real Party in Interest as PURAC
BIOCHEM B.V. (see App. Br. 1).
2 We have considered and refer to the Specification of Aug. 11, 2015
(“Spec.”); Non-Final Action of Nov. 2, 2017 (“Non-Final Act.”); Appeal
Brief of Mar. 30, 2018 (“App. Br.”); Examiner’s Answer of May 2, 2018
(“Ans.”); and Reply Brief of June 25, 2018 (“Reply Br.”).
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Statement of the Case
Background
“Methyl lactate is a compound with many uses” including as “a
starting material for acrylic acid and other esters” (Spec. 1:4–15). “Methyl
lactate can be manufactured from lactic acid, which is obtained through
fermentation. In view of the various uses of methyl lactate, there is need in
the art for a method for manufacturing methyl lactate, which is efficient and
which provides methyl lactate in high yield” (id. 1:17–21).
The Claims
Claims 1–4, 6, and 8–20 are on appeal.3 Claim 1 is representative and
reads as follows:
1. Process for preparing methyl lactate comprising the
steps of
- providing an aqueous liquid comprising lactic acid,
methanol, and at least 5 wt.% of a dissolved chloride salt
selected from magnesium chloride, calcium chloride, and
zinc chloride,
- subjecting the aqueous liquid to an esterification step
by bringing the aqueous liquid to reaction conditions,
thereby obtaining methyl lactate, wherein
an extractant is provided to the reaction mixture
before, during, and/or after formation of methyl
lactate, and
the extractant is selected from the group of C5+
ketones, C3-C10 ethers, and C6-C10 aromatic
compounds,
- subjecting the reaction mixture to a liquid-liquid
separation step wherein an organic phase comprising methyl
lactate and extractant is separated from an aqueous phase
comprising dissolved chloride salt.

3 Claims 5 and 7 were allowed (see Ans. 67).
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The Issues
A. The Examiner rejected claims 1–4, 14, and 17–19 under 35 U.S.C.
§ 103(a) as obvious over El Paso4 and Poma5 (Ans. 3–6).
B. The Examiner rejected claims 1–4, 8–12, 14, and 17–19 under 35
U.S.C. § 103(a) as obvious over El Paso, Poma, and Van Krieken6 (Ans. 6–
9).
C. The Examiner rejected claims 1–4, 6, and 14–20 under 35 U.S.C.
§ 103(a) as obvious over El Paso, Poma, and Polarity Index (2016)7 (Ans. 9–
10).
D. The Examiner rejected claims 1–4, 13, 14, and 17–19 under 35 U.S.C.
§ 103(a) as obvious over El Paso, Poma, and Hagemayer8 (Ans. 10–11).

A. 35 U.S.C. § 103(a) over El Paso and Poma
The Examiner finds:
El Paso Products teaches a method of preparing methyl lactate
(lactic acid methyl ester) wherein lactic acid is mixed with a
water miscible alcohol (methanol) in a esterification step then
extracted under mild heating with a water immiscible organic
solvent wherein lactic acid in the aqueous phase is transformed
into the ester of lactic acid (methyl lactate) in the organic phase
which is distilled (liquid-liquid separation step) to recover the

4 El Paso, GB 1,282,926, published July 26, 1972.
5 Poma et al; The action of neutral salts on the constants of chemical
equilibrium, in 24(1) PROCEEDINGS OF THE NATIONAL ACADEMY OF LINCEI,
CLASS OF PHYSICS, MATHEMATICS AND NATURAL REPORTS 747–754 (1915)
(English Translation).
6 Van Krieken et al., WO 2005/123647 A1, published Dec. 29, 2005.
7 Polarity Index, http://www.maro.lsu.edu/howto/solvents/Polarity%20
index.htm (2016).
8 Hagemeyer, Jr., US 2,417,748, issued Mar. 18, 1947.
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immiscible solvent and the residue distilled to yield the methyl
lactate.

(Ans. 4). The Examiner finds El Paso teaches “salts may be used as
catalysts” (id.). The Examiner acknowledges that El Paso does not teach “a
method wherein lactic acid and methanol are combined with a dissolved
chloride salt (magnesium chloride)” (id. 5).
The Examiner finds Poma teaches “the use of neutral salts (such as
magnesium chloride) in esterification reactions involving methyl alcohol
(methanol)” (Ans. 5).
The Examiner finds it obvious to use neutral salts including
magnesium chloride in the method of El Paso because “El Paso Products
teaches that any salt may be used as an esterification catalyst and Poma et at.
[sic] teaches that magnesium chloride is known to be suitable as an
esterification catalyst” (Ans. 5).
The issue with respect to this rejection is: Does a preponderance of
the evidence of record support the Examiner’s conclusion that El Paso and
Poma render the claims obvious?
Findings of Fact
1. El Paso teaches “a process for the conversion of lactic acid to
an ester of a low molecular weight alcohol. These esters have chemical and
physical properties conducive to easy recovery, purification, handling,
storage, and further processing” (El Paso 5:32–38).
2. El Paso teaches:
An acidified aqueous solution containing lactic acid . . . is
mixed with a water miscible alcohol. The resulting solution is
then extracted under mild heating with a water immiscible
organic solvent. As a result of these operations, lactic acid in
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the aqueous phase is transformed into the ester of lactic acid in
the organic phase. The organic phase is distilled to recover the
immiscible solvent. The residue from this process is then
distilled to yield the ester of lactic acid in pure form.
(El Paso 5:40–52).
3. El Paso teaches, in Example 8, that:
Technical grade lactic acid mixture, as a 44% aqueous solution
(500 grams) was mixed with ethanol (500 grams) and sulfuric
acid (96%, 50 grams) . . . and then placed in a vessel heated to
50°C. This heated solution was fed into a continuous counter-
current extractor near the top and benzene was fed into the
extractor at the bottom . . . The benzene, after entering the
extractor, flowed upward as small droplets passing through the
continuous aqueous phase which flowed slowly downward.
The aqueous phase left the extractor at the bottom. . . . The
benzene extract left the extractor from the top. . . . Water-white
ethyl lactate (92.4% pure) was obtained in about 50% yield.
(El Paso 11:128–12:39).
4. El Paso teaches, in Example 11, that the “experiment of
Example VIII was repeated using chloroform instead of benzene and using
methanol instead of ethanol. About 50% of the lactic acid was extracted as
methyl lactate. Distillation of the extract yielded water-white methyl lactate
(98.8% pure)” (El Paso 12:62–67).
5. El Paso teaches that “it is highly preferable that a small amount
of a catalyst such as an acidic or metallic catalyst be present during the
esterification reaction to enable the reaction to reach equilibrium as soon as
possible” (El Paso 6:35–40).
6. El Paso teaches regarding the catalyst that “[g]enerally 2% to
15% by weight of the total amount of the solution is sufficient” (El Paso
6:40–42).
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7. El Paso teaches that in “specialized instances, such as with
solutions of amino acids, non-acidic catalysts such as salts of copper or other
other [sic] metals may be used” (El Paso 6:59–62).
8. Poma teaches that in “order to complete the study of the action
of neutral salts on the stability of homogeneous systems containing methyl
alcohol or ethyl alcohol and different absolute amounts of water, we have
made the following experiments, in which, as usual, the acid was from
etherification of the acetic acid” (Poma 2).
9. Table 5a of Poma is reproduced below (original quality is poor)

Table 5a shows a formulation with water, methanol, and magnesium
chloride in an acetic acid etherification reaction (see Poma 2–3).
10. Poma teaches “that the action exerted by the accelerator neutral
salts on individual speed etherification and hydrolysis, as may be inferred
from the changes of the corresponding reaction constants k1 and k2, it is,
generally, the greater the higher the affinity for the water of neutral salts
used” (Poma 9).
Principles of Law
A prima facie case for obviousness “requires a suggestion of all
limitations in a claim,” CFMT, Inc. v. Yieldup Int’l Corp., 349 F.3d 1333,
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1342 (Fed. Cir. 2003) and “a reason that would have prompted a person of
ordinary skill in the relevant field to combine the elements in the way the
claimed new invention does.” KSR Int’l Co. v. Teleflex Inc., 550 U.S. 398,
418 (2007).
Analysis
Appellant contends that
the Examiner has not met his burden of presenting a prima facie
case of obviousness at least because (1) the Examiner’s
assertions that El Paso teaches that any salt may be used as a
catalyst (specifically an esterification catalyst) overstates El
Paso’s teaching and/or is based on mere speculation that is not
supported by the evidence of record, and (ii) one skilled in the
art would not have interpreted Poma as disclosing or suggesting
that the neutral salts (such as magnesium chloride) described
therein are “catalysts” (i.e., effective to enable the equilibrium
to be reached as soon as possible).
(App. Br. 11). Appellant also contends “the art does not suggest that neutral
salts selected from magnesium chloride, calcium chloride, and zinc chloride
are materials known to be suitable for an intended use as a catalyst for an
esterification reaction and thus proposed modification lacks a rational
underpinning to support the legal conclusion of obviousness” (id.).
The Examiner responds that El Paso teaches “any catalyst may be
used during the esterification reaction to enable the reaction to reach
equilibrium as soon as possible, wherein salts may be used as catalysts”
(Ans. 13). The Examiner also contends that the “Poma reference clearly
performs an experiment involving the presence and absence of the neutral
salt MgCl2” (id.).
We agree with Appellant because the Examiner overstates the
teachings of both El Paso and Poma. El Paso does teach the use of metallic
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catalysts during esterification reactions (FF 5) but only teaches the use of
metal salts in the context of amino acid solutions (FF 7). Thus, El Paso
provides no generic suggestion of metal salts as catalysts of esterification
reactions, including esterification of lactic acid into methyl lactate.
Poma has a table that includes magnesium chloride (FF 9) and
discusses neutral salts and etherification of acetic acid (FF 8) as well as
“accelerator neutral salts” (FF 10). However, the evidence in Poma does not
persuasively suggest any reason why magnesium chloride, calcium chloride,
or zinc chloride should be included in a reaction involving the esterification
of lactic acid into methyl lactate.
While the Examiner is correct that non-preferred embodiments may
be used to support obviousness, and that preferred embodiments do not teach
away (see Ans. 16), the Examiner has provided no persuasive reason to
select the salt of Poma for use in the esterification reaction of El Paso. “We
must still be careful not to allow hindsight reconstruction of references to
reach the claimed invention without any explanation as to how or why the
references would be combined to produce the claimed invention.”
Innogenetics, N.V. v. Abbott Labs., 512 F.3d 1363, 1374 n.3 (Fed. Cir.
2008).
Conclusion of Law
A preponderance of the evidence of record does not support the
Examiner’s conclusion that El Paso and Poma render the claims obvious.
B.-D. 35 U.S.C. § 103(a)
Having reversed the obviousness rejection of claim 1 over El Paso and
Poma for the reasons given above, we also find that the further combinations
with Van Krieken, Polarity Index (2016), and Hagemeyer do not suggest the
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use of the recited metal chloride salts and therefore do not render the
rejected claims obvious for the same reasons.

CONCLUSION
In summary:
Claim(s) Rejected Basis Affirmed Reversed
1–4, 14, 17–19  § 103(a) El
Paso, Poma
  1–4, 14, 17–19 
1–4, 8–12, 14, 17–19  § 103(a) El
Paso, Poma,
Van Krieken
  1–4, 8–12, 14, 17–19 
1–4, 6, 14–20 § 103(a) El
Paso, Poma,
Polarity Index
(2016)
  1–4, 6, 14–20
1–4, 13, 14, 17–19 § 103(a) El
Paso, Poma,
Hagemayer
  1–4, 13, 14, 17–19
Overall Outcome     1–4, 6, 8–20 

REVERSED