Trials@uspto.gov
`571-272-7822
`
`
`
`
`
` Paper No. 43
`Entered: March 3, 2017
`
`UNITED STATES PATENT AND TRADEMARK OFFICE
`____________
`
`BEFORE THE PATENT TRIAL AND APPEAL BOARD
`____________
`
`E. I. DU PONT DE NEMOURS AND COMPANY AND
`ARCHER-DANIELS-MIDLAND COMPANY,
`Petitioners,
`
`v.
`
`FURANIX TECHNOLOGIES B.V.,
`Patent Owner.
`____________
`
`Case IPR2015-01838
`Patent 8,865,921 B2
`____________
`
`
`
`Before TONI R. SCHEINER, SHERIDAN K. SNEDDEN and
`CHRISTOPHER G. PAULRAJ, Administrative Patent Judges.
`
`PAULRAJ, Administrative Patent Judge.
`
`
`
`FINAL WRITTEN DECISION
`35 U.S.C. § 318(a) and 37 C.F.R. § 42.73
`
`
`
`
`

`

`IPR2015-01838
`Patent 8,865,921 B2
`
`I.
`
`INTRODUCTION
`
`E. I. du Pont de Nemours and Company and Archer-Daniels-Midland
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`Company (collectively, “Petitioners”) filed a Petition (Paper 1, “Pet.”),
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`requesting institution of an inter partes review of claims 1–10 of
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`U.S. Patent No. 8,865,921 B2 (Ex. 1001, “the ’921 Patent”). Furanix
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`Technologies B.V. (“Patent Owner”) did not file a Preliminary Response.
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`We have jurisdiction under 35 U.S.C. § 314, which provides that an inter
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`partes review may not be instituted “unless . . . there is a reasonable
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`likelihood that the petitioner would prevail with respect to at least 1 of the
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`claims challenged in the petition.” We determined that the information
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`presented in the Petition demonstrated that there was a reasonable likelihood
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`that Petitioners would prevail in challenging claims 1–5 and 7–9 as
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`unpatentable under 35 U.S.C. § 103(a). Pursuant to 35 U.S.C. § 314, the
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`Board instituted trial on March 9, 2016, as to those claims of the ‘977 Patent.
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`Paper 10 (“Institution Decision”; “Inst. Dec.”). We denied Petitioners’
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`request for rehearing of our decision to deny institution as to the
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`patentability challenge for claims 6 and 10. Paper 20.
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`Following our institution, Patent Owner filed a Response to the
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`Petition. Paper 23 (“PO Resp.”). Petitioners filed a Reply to Patent
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`Owner’s Response. Paper 29 (“Reply”). An oral hearing was held on
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`November 16, 2016. The transcript of the hearing has been entered into the
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`record. Paper 42 (“Tr.”).
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`We have jurisdiction under 35 U.S.C. § 6. This Final Written
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`Decision is issued pursuant to 35 U.S.C. § 318(a) and 37 C.F.R. § 42.73.
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`Based on the record before us, we conclude that Petitioners have not
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`demonstrated by a preponderance of the evidence that claims 1–5 and 7–9 of
`
`
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`2
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`IPR2015-01838
`Patent 8,865,921 B2
`
`the ’921 Patent are unpatentable based on the obviousness challenges
`
`presented in the Petition.
`
`A.
`
`Related Proceedings.
`
`The parties have not identified any separate related matters under 42
`
`C.F.R. § 42.8(b)(2). Pet. 1; Paper 5, 1.
`
`B.
`
`The ’921 Patent (Ex. 1001)
`
`The ’921 patent issued on October 21, 2014, and claims priority to a
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`provisional application filed on October 7, 2009. See Ex. 1001, Title Page.
`
`It names Cesar Muñoz De Diego, Matheus Adrianus Dam, and Gerardus
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`Johannes Maria Gruter as the inventors. Id.
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`The ’921 patent relates generally to methods for preparing 2, 5-furan
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`dicarboxylic acid (FDCA), or a dialkyl ester of FDCA, by contacting 5-
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`hydroxymethylfurfural (HMF), and/or derivatives thereof, with an oxygen-
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`containing gas in the presence of oxidation catalysts comprising cobalt (Co),
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`manganese (Mn), and bromine (Br) (i.e., a Co/Mn/Br catalyst), and an acetic
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`acid solvent at elevated temperatures. Id., Abstract, 1:18–26, 2:39–45. The
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`’921 patent states that “FDCA can be produced in particular from esters of
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`HMF, such as for example 5-acetoxymethylfurfural (AMF) or a mixture of
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`one or more of these compounds with HMF, such as for example from a
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`mixture of AMF and HMF.” Id. at 1:21–24. The ’921 patent further
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`discusses the use of FDCA obtained according to the process described
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`therein to prepare a dialkyl ester of 2,5-dicarboxylic acid by the reaction of
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`FDCA with a C1–C5 alkyl alcohol. Id. at 5:20–41. The ’921 patent
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`acknowledges that the esterification of FDCA was known in the prior art.
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`Id. at 5:42–58.
`
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`3
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`IPR2015-01838
`Patent 8,865,921 B2
`
`
`According to the ’921 patent, FDCA has been identified as a priority
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`chemical for establishing a “green” chemistry industry, but no commercial
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`process exists for its production. Id. at 1:34–38. The specification states
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`that FDCA, a furan derivative, is often synthesized in the laboratory from
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`HMF obtained from carbohydrate containing sources such as glucose,
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`fructose, sucrose, and starch. Id. at 1:30–43. The derivatives of HMF are
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`known to be potential and versatile fuel components and precursors for the
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`production of plastics. Id. at 1:44–46. The specification identifies prior art
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`processes for the oxidation of HMF to FDCA with a Co/Mn/Br catalyst at
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`temperatures ranging from 50 to 125oC, which resulted in low reactivity or
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`yield loss. Id. at 1:48–67, 2:1–35. The ’921 patent seeks to improve prior
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`art yields by controlling the temperature and/or pressure under which the
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`oxidation reaction occurs. Id. at 4:34–61.
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`In particular, the ’921 patent specification explains that “[t]he pressure
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`in a commercial oxidation process may vary within wide ranges,” and “is
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`determined by the solvent (e.g., acetic acid) pressure at a certain
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`temperature.” Id. at 4:34–39. Moreover, the pressure is preferably selected
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`to maintain the solvent in the liquid phase, which “means that pressures
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`between 5 and 100 bar can be used with a preference for pressures between
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`10 and 80 bar.” Id. at 4:39–43. The oxidant can be an oxygen-containing
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`gas, such as air, which “can be continuously fed to and removed from the
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`reactor,” in which case “the oxygen partial pressure will suitably be between
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`1 and 30 bar or more preferably between 1 and 10 bar.” Id. at 4:43–46, 51–
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`55. Conversely, all of the oxygen-containing gas can be supplied at the start
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`of the reaction, but this will require a significantly higher pressure. Id. at
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`4:45–51. The specification further explains that “[t]he temperature of the
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`4
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`IPR2015-01838
`Patent 8,865,921 B2
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`reaction mixture is at least 140° C., preferably from 140 and 200° C., most
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`preferably between 160 and 190° C.” Id. at 4:56–58. The specification
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`notes that “[g]ood results” were achieved at about 180°C, but cautions that
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`“[t]emperatures higher than 180° C may lead to decarboxylation and to other
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`degradation products.” Id. at 4:58–61.
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`The ’921 patent includes working examples describing experiments in
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`which the oxidation reaction was carried out with a Co/Mn/Br catalyst at an
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`air pressure ranging from 20–60 bars and temperatures ranging from 100 to
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`220°C. Id. at 6:8–11. More particularly, Example 1 describes the oxidation
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`of HMF and/or AMF at 180°C for 1 hour with 20 bar air pressure, which
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`resulted in FDCA yields of up to 78.08%. Id. at 6:34–46, Table 1. Example
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`2 provides a comparative example in which AMF oxidation was conducted
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`at 100°C and 30 bar for 2 hours, showing that FDCA yields under those
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`conditions were lower than the results obtained at higher temperature. Id. at
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`6:50–62, Table 2.
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`C. Illustrative Claims
`
`Claims 1–5 and 7–6 are challenged in this inter partes review.
`
`Independent claim 1 is illustrative, and reproduced below:
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`1. A method for the preparation of 2,5-furan dicarboxylic acid
`comprising the step of contacting a feed comprising a compound
`selected from the group consisting of 5-hydroxymethylfurfural
`(“HMF”), an ester of 5-hydroxymethylfurfural, 5-methylfurfural, 5-
`(chloromethyl)furfural, 5-methylfuroic acid, 5-(chloromethyl)furoic
`acid, 2,5-dimethylfuran and a mixture of two or more of these
`compounds with an oxygen-containing gas, in the presence of an
`oxidation catalyst comprising both Co and Mn, and further a source of
`bromine, at a temperature between 140° C and 200° C at an oxygen
`partial pressure of 1 to 10 bar, wherein a solvent or solvent mixture
`comprising acetic acid or acetic acid and water mixtures is present.
`
`
`
`5
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`IPR2015-01838
`Patent 8,865,921 B2
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`Independent claim 7 is directed to the preparation of a dialkyl ester of
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`FDCA, and additionally recites the step of “esterifying the thus obtained
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`product.”
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`D. Patentability Challenges
`
`The following patentability challenges are at issue in this proceeding:
`
`References
`
`The ’732 publication,1 RU
`’177,2 and the ’318 application3
`
`The ’732 publication,
`Lewkowski,4 Oae,5 RU ’177,
`and the ’318 application
`
`Basis
`
`§ 103(a)
`
`§ 103(a)
`
`Claims challenged
`
`1–5
`
`7–9
`
`
`
`In addition to the teachings of the references, Petitioners rely upon the
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`Declarations of Kevin J. Martin, Ph.D. (Ex. 1009; Ex. 1028) in support of
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`these challenges.
`
`
`
`
`
`
`
`
`1 Grushin et al., WO 01/72732 A2, published Oct. 4, 2001 (Ex. 1002).
`2 Slavinskaya et al., USSR Patent RU-448177A1, published Oct. 30, 1974
`(Ex. 1007, with certified English translation).
`3 Lilga et al., US 2008/0103318 A1, published May 1, 2008 (Ex. 1008).
`4 Lewkowski, Synthesis, Chemistry and Applications of 5-
`Hydroxymethylfurfural and its Derivatives, ARKIVOC 2001 (i) 17–54,
`Published Online on Aug. 8, 2001 (Ex. 1005).
`5 Oae et al., A Study of the Acid Dissociation of Furan- and
`Thiophenedicarboxylic Acids and of the Alkaline Hydrolysis of Their Methyl
`Esters, SOC. JPN. 1965, 38, Aug. 1965, at 1247 (Ex. 1006).
`
`
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`6
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`IPR2015-01838
`Patent 8,865,921 B2
`
`II. DISCUSSION
`
`A. Claim Construction
`
`We interpret claims of an unexpired patent using the “broadest
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`reasonable construction in light of the specification of the patent in which
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`[they] appear[].” 37 C.F.R. § 42.100(b); Cuozzo Speed Techs., LLC v. Lee,
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`136 S. Ct. 2131, 2146 (2016). Under the broadest reasonable construction
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`standard, claim terms are given their ordinary and customary meaning, as
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`would be understood by one of ordinary skill in the art at the time of the
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`invention. In re Translogic Tech., Inc., 504 F.3d 1249, 1257 (Fed. Cir.
`
`2007). “Absent claim language carrying a narrow meaning, the PTO should
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`only limit the claim based on the specification . . . when [it] expressly
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`disclaim[s] the broader definition.” In re Bigio, 381 F.3d 1320, 1325 (Fed
`
`Cir. 2004). “Although an inventor is indeed free to define the specific terms
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`used to describe his or her invention, this must be done with reasonable
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`clarity, deliberateness, and precision.” In re Paulsen, 30 F.3d 1475, 1480
`
`(Fed. Cir. 1994).
`
`We determine that no explicit construction of any claim term is
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`necessary to resolve the issues in this case. See, e.g., Wellman, Inc. v.
`
`Eastman Chem. Co., 642 F.3d 1355, 1361 (Fed. Cir. 2011) (“[C]laim terms
`
`need only be construed ‘to the extent necessary to resolve the
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`controversy.’”) (quoting Vivid Techs., Inc. v. Am. Sci. & Eng’g, Inc.,
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`200 F.3d 795, 803 (Fed. Cir. 1999)).
`
`B. Prior Art Relied Upon
`
`Petitioners rely upon the following prior art in their challenges.
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`
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`7
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`IPR2015-01838
`Patent 8,865,921 B2
`
`
`1. The ’732 publication (Ex. 1002)
`
`The ’732 publication describes the oxidation of HMF to FDCA, and
`
`the subsequent decarbonylation to unsubstituted furan. Ex. 1002, Title,
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`2:17–20.6 The catalyst used for the oxidation process described in the ’732
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`publication “can be comprised of Co and/or Mn, and Br, and optionally
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`[zirconium,] Zr.” Id. at 6:22–24. Acetic acid is identified as a preferred
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`solvent because FDCA is insoluble in it, thereby facilitating purification. Id.
`
`at 9:14–21.
`
`The ’732 publication explains further that “[f]or preparation of diacid,
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`the preferred temperatures are about 50o to 250oC, most preferentially about
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`50o to 160oC,” and “[t]he corresponding pressure is such to keep the solvent
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`mostly in the liquid phase.” Id. at 8:2–5. The ’732 publication discloses
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`examples wherein “[p]lacing HMF in reactors with acetic acid and catalyst
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`metals and having them react with air at 1000 psi (7 MPa) gave good yields
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`of FD[C]A.” Id. at 16:3–4. In Examples 38–40, “the temperature was
`
`staged – initially it was held at 75°C for 2 hrs. and then raised to 150°C for
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`two hrs,” which “gave higher yields.” Id. at 16:13–15, Table 4.
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`The ’732 publication is identified as prior art in the background
`
`section of the ’921 patent, which indicates that “[t]he maximum FDCA yield
`
`reported is 59%, obtained at 105° C.” Ex. 1001, 1:48–50.
`
`
`6 The ’732 publication uses the acronym “FDA” for 2,5-furan dicarboxylic
`acid. For the sake of consistency, we will refer to the compound as FDCA.
`We also refer herein to the page numbers added to the very bottom of the
`exhibit (e.g., “Petitioners’ Exhibit 1002, Page 2 of 23”).
`
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`8
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`IPR2015-01838
`Patent 8,865,921 B2
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`
`2. RU ’177 (Ex. 1007)
`
`RU ’177 is an “Inventor’s Certificate” issued by the former Union of
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`Soviet Socialist Republics (USSR), which also teaches a method for
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`producing FDCA. Ex. 1007, Title. Specifically, RU ’177 claims a process
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`of producing FDCA using air oxidation wherein “5-methylfurfural [5MF] is
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`subject to oxidation and mixed valance metal salts, such as a mixture of
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`cobalt acetate and manganese acetate, as well as bromine-containing
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`compounds, such as ammonium bromide, in the aliphatic carboxylic acid
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`solution are used as a catalyst.” Id. at 2, col. 4 (claim 1). RU ’177 also
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`includes a claim specifying that the “oxidation is conducted at the
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`temperature of 115–140°C and air pressure of 10–50 atm.” Id. at 2, col. 4
`
`(claim 2). RU ’177 further discloses that oxidation is “typically conducted
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`under 115-140°C and air pressure of 10-15 atm.” Id. at 1, col. 1. In
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`Example 1 of RU ’177, 5MF was reacted at 118°C and 20 atm of pressure
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`(4.26 bar pO2) for 4.5 hours and then the temperature was increased to
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`130°C and pressure increased to 30 atm (6.38 bar pO2). Id. at 2, col. 3.
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`RU ’177 states the method disclosed therein has a number of
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`advantages, i.e., “it utilizes readily available and inexpensive reagents as the
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`initial compound and catalysts [and] the method is a one-step process.” Id.
`
`at 1, col. 2.
`
`3. The ’318 application (Ex. 1008)
`
`The ’318 application also relates to a method of oxidizing HMF to
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`produce various derivatives, including FDCA. Ex. 1008 ¶ 3. More
`
`specifically, the ’318 application teaches that “[t]he starting material
`
`comprising HMF is provided into a reactor and at least one of air or O2 is
`
`provided as oxidant.” Id. ¶ 50. The ’318 application indicates that,
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`IPR2015-01838
`Patent 8,865,921 B2
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`depending upon the desired reaction rate, the pressure utilized may range
`
`from atmospheric pressure to the pressure rating of the equipment, and “[a]
`
`preferred pressure can typically be in the range of 150-500 psi.” Id.
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`“Similarly an appropriate reaction temperature can be from about 50° C to
`
`about 200° C, with a preferred range of from 100° C through about 160° C.”
`
`Id.
`
`The ’318 application states that “under particular reaction conditions,
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`HMF conversions of 100% were achieved with selectivity to FDCA as high
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`as 98% relative to all other reaction products, intermediates and
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`byproducts.” Id. ¶ 55. In Example 1, 98% FDCA selectivity was achieved
`
`using a Pt/ZrO2 catalyst under conditions of 150 psi pressure and 100°C
`
`temperature. Id. ¶¶ 67–68.
`
`4. Lewkowski (Ex. 1005)
`
`Lewkowski discusses the methods of synthesis of FDCA, and its
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`chemistry and application. Ex. 1005, 17. Lewkowski states “[t]he synthesis
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`of diethyl ester and dimethyl ester . . . have been reported.” Id. at 44.
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`Lewkowski cites Oae (Ex. 1006) for the synthesis process of dimethyl ester.
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`Id. Lewkowski discloses that the diethyl ester of FDCA has “a strong
`
`anaesthetic action similar to cocaine,” and that another ester form of
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`FDCA—dicalcium 2,5-furandicarboxylate—was shown to have antibacterial
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`activity. Id. at 45.
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`5. Oae (Ex. 1006)
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`Oae relates to the acid dissociation of furandicarboxylic acids and the
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`alkaline hydrolysis of their methyl esters. Ex 1006, 1247. Specifically,
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`Oae states that dimethyl esters of FDCA were synthesized in the following
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`manner: “Dicarboxylic acid (0.064 mol.) was refluxed with 10 ml. of
`
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`10
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`IPR2015-01838
`Patent 8,865,921 B2
`
`
`anhydrous methanol in a benzene solution with one or two drops of
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`concentrated sulfuric acid for several hours,” and “[a]fter the removal of the
`
`excess methanol, the residual dimethyl ester was recrystallized from a
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`suitable solvent several times to give the correct melting point.” Id. at
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`1249. This method yielded 68.7% dimethyl 2,5-furandicarboxylate. Id.
`
`6. Partenheimer (Ex. 1003)7
`
`Partenheimer is cited and discussed in the background section of the
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`’921 patent. Ex. 1001, 1:55–2:6. Partenheimer describes synthesis of 2,5-
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`diformylfuran and FDCA by catalytic air-oxidation of HMF. Ex. 1003, 102
`
`(Title). Specifically, Partenheimer teaches synthesis of FDCA by contacting
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`HMF in the presence of Co/Mn/Br catalysts Co, and with an air pressure of
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`70 bar at temperatures up to 125o C. Id. at 105 (Table 3).
`
`According to Partenheimer, the advantages of the oxidation process
`
`described therein are 1) “that the catalyst is composed of inexpensive,
`
`simple metal acetate salts and a source of ionic bromide (NaBr, HBr, etc.),”
`
`
`7 Partenheimer et al., Synthesis of 2, 5-Diformylfuran and Furan-2, 5-
`Dicarboxylic Acid by Catalytic Air-Oxidation of 5-Hydroxymethylfurfural.
`Unexpectedly Selective Aerobic Oxidation of Benzyl Alcohol to
`Benzaldehyde with Metal/Bromide Catalysts, 343 ADV. SYNTH. CATAL. 102–
`111, Published Online on Feb. 6, 2001 (Ex. 1003) (“Partenheimer”).
`Although Partenheimer did not form the basis for the specific patentability
`challenges upon which we instituted trial, both Petitioners and Patent Owner
`have relied upon Partenheimer’s teachings to support their respective
`arguments. See Pet. 15–16; PO Resp. 3, 8, 10, 20, 26–28; Reply 7, 10–12,
`19. We, therefore, consider Partenheimer as relevant “background” art in
`our evaluation of Petitioners’ patentability challenges. See Ariosa
`Diagnostics v. Verinata Health, Inc., 805 F.3d 1359, 1365 (Fed. Cir. 2015)
`(“Art can legitimately serve to document the knowledge that skilled artisans
`would bring to bear in reading the prior art identified as producing
`obviousness.”).
`
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`IPR2015-01838
`Patent 8,865,921 B2
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`2) “[t]he reaction times are within a few hours at easily accessible
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`temperatures,” and 3) “[t]he acetic acid solvent is inexpensive and nearly all
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`alcohols are highly soluble in it.” Id. at 106. Partenheimer teaches that the
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`reactions are performed at air pressure of 70 bar and cautions that “[t]he use
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`of high pressures and the use of dioxygen/nitrogen mixtures is potentially
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`explosive and dangerous,” and “should be performed only with adequate
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`barriers for protection.” Id. at 110.
`
`C. Level of Ordinary Skill in the Art
`
`Petitioners’ expert Dr. Martin opines that “one of ordinary skill in the
`
`art of oxidation of aromatic compounds, such as furan based compounds, is
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`a person with a doctorate degree in chemistry and/or chemical engineering
`
`and having at least 5 years of experience in oxidation catalysis and chemical
`
`process development.” Ex. 1009 ¶ 14. Patent Owner contends that a person
`
`of ordinary skill in the art (“POSA” or “skilled artisan”) for the ’921 patent
`
`would have had “at least a bachelor’s degree in chemistry or chemical
`
`engineering, having worked in the field of chemical process development for
`
`at least five years and having experience in the preparation of furan
`
`compounds from biomass and in the catalysis of oxidation of furan
`
`compounds for a similar period.” PO Resp. 14 (citing Ex. 2003 ¶ 44). In its
`
`Reply, Petitioners contend that Patent Owner’s proposed level of skill in the
`
`art places too many limitations, “whereas Petitioner’s hypothetical POSA –
`
`as defined by Dr. Martin – would have the knowledge and experience to
`
`understand that catalyst concentration is a result-effective variable that
`
`impacts yield.” Reply 2 (citing Ex. 1028 ¶ 7).
`
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`Patent 8,865,921 B2
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`
`Although we do not discern a significant difference between the
`
`qualifications for a skilled artisan proposed by the parties, we determine that
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`Patent Owner’s proposed level of skill in the art is more appropriate for our
`
`analysis. Specifically, we determine that a skilled artisan need not have a
`
`doctorate degree. Patent Owner’s expert, Dr. Wayne P. Schammell, Ph.D.,
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`states that in his experience “individuals working in the field often have BS
`
`or MS degrees with relevant experience in the field.” Ex. 2003 ¶ 44. At his
`
`deposition, Dr. Martin acknowledged that a chemist with a master’s degree
`
`could be a skilled artisan “with appropriate experience,” and that one with a
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`bachelor’s degree that focuses on organic chemistry and at least 10 years of
`
`experience could also be a skilled artisan. Ex. 1027, 112:21–114:1. We
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`have also taken into account the level of skill in the art that is reflected in the
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`prior art references themselves. See Okajima v. Bourdeau, 261 F.3d 1350,
`
`135 (Fed. Cir. 2001). With regard to Petitioners’ contention as to whether a
`
`skilled artisan would have the knowledge and experience to understand
`
`whether a catalyst concentration is a result-effective variable (Reply 2), we
`
`determine that issue is more appropriately considered as part of the
`
`substance of the obviousness analysis rather than our determination of the
`
`appropriate skill level for the ’921 patent.
`
`D. Analysis of Petitioners’ Patentability Challenges
`
`Petitioners contend that claims 1–5 are obvious based on the teachings
`
`of the ’732 publication in combination with RU ’177 and the ’318
`
`application. Pet. 27–40. Petitioners additionally contend that claims 7–9 are
`
`obvious over the combination of the ’732 publication, RU ’177, and the ’318
`
`application in further view of Lewkowski and Oae. Id. at 45–49.
`
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`13
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`IPR2015-01838
`Patent 8,865,921 B2
`
`
`Independent claim 1 requires the preparation of FDCA by contacting a
`
`feed comprising HMF, or certain derivatives of HMF, with an oxygen-
`
`containing gas in the presence of a Co/Mn/Br oxidation catalyst, and an
`
`acetic acid-based solvent or solvent mixture, at a temperature between 140oC
`
`and 200oC, and at an oxygen partial pressure (pO2) of 1 to 10 bar. Ex. 1001,
`
`7:60–8:6. Independent claim 7 recites the same process of claim 1, and
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`further recites the additional step of “esterifying the thus obtained product”
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`in order to produce a dialkyl ester of FDCA. Id. at 9:1–14. We focus our
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`analysis on these independent claims.
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`In our Institution Decision, we determined that Petitioners
`
`demonstrated a reasonable likelihood of prevailing with respect to these
`
`obviousness challenges based on the preliminary record at the time and
`
`instituted trial on that basis. Inst. Dec. 13–15, 18–19. We have now
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`reconsidered the arguments and evidence presented with the Petition, along
`
`with the additional arguments and evidence presented with Patent Owner’s
`
`Response and Petitioners’ Reply, under the preponderance of the evidence
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`standard applicable to Final Written Decisions in an inter partes review. 35
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`U.S.C. § 316(e).
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`As an initial matter, we comment on Petitioners’ attempts to apply the
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`“prima facie” burden-shifting framework typically applied during patent
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`examination to argue obviousness in this proceeding. See, e.g., Pet. 8
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`(“Thus, the claims of the ’921 patent are prima facie rendered obvious in
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`view of the ’732 publication because there is no evidence that reducing the
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`oxygen partial pressure by 4.5 bar[] is critical to the methods or process of
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`oxidizing HMF to FDCA.”); id. at 50 (asserting that “[a] prima facie case of
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`obviousness exists where the claimed ranges and prior art ranges do not
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`overlap but are close enough that one skilled in the art would have expected
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`them to have the same properties”) (citing MPEP § 2144.05); Reply 9
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`(arguing that “[t]his overlap [in temperature] alone supports a finding of a
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`prima facie case of obviousness.”); id. at 14–15 (“Because the claimed
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`ranges ‘overlap or lie inside ranges disclosed by the prior art,’ a prima facie
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`case of obviousness exists.”). Based on the prior art’s disclosure of broader
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`or overlapping ranges, Petitioners seek to shift the burden to Patent Owner to
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`rebut their alleged prima facie case by showing “criticality” with the claimed
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`ranges. See, e.g., Reply 9, 13, 21–23. The Federal Circuit has stated,
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`however, that such a “burden-shifting framework does not apply in the
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`adjudicatory context of an [inter partes review].” In re Magnum Oil Tools
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`Int'l, Ltd., 829 F.3d 1364, 1375 (Fed. Cir. 2016). Rather, “[i]n an inter
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`partes review, the burden of persuasion is on the petitioner to prove
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`‘unpatentability by a preponderance of the evidence,’ 35 U.S.C. § 316(e),
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`and that burden never shifts to the patentee.” Dynamic Drinkware, LLC v.
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`Nat'l Graphics, Inc., 800 F.3d 1375, 1378 (Fed. Cir. 2015) (citation
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`omitted).
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`Taking Petitioners’ burden of persuasion into account, we find that the
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`evidence fails to show it would have been obvious to adjust both the
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`temperature and pO2 in the processes taught by the prior art to within the
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`claimed ranges as a matter of routine optimization. We have also considered
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`Patent Owner’s “objective evidence” concerning unexpected results,
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`satisfaction of a long-felt but unmet need, and copying, but find that
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`evidence to be less probative in supporting a conclusion of non-obviousness.
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`Nonetheless, based upon our consideration of the record as a whole, we
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`determine that Petitioners have not established the unpatentability of claims
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`1–5 and 7–9 by a preponderance of the evidence. We address these issues
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`separately in further detail below.
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`1. Optimization of Temperature to Between 140° and 200°C
`and Oxygen Partial Pressure to Between 1 and 10 Bar
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`Although the prior art disclosed processes with broader or overlapping
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`temperature or pressure ranges, none of the references relied upon by
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`Petitioners expressly taught a process in which HMF or its derivatives were
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`oxidized to FDCA using a Co/Mn/Br catalyst at a reaction temperature of
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`between 140°C and 200°C while also maintaining the pO2 between 1 and 10
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`bar as required by the challenged claims of the ’921 patent. Petitioners,
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`therefore, rely upon an “optimization” rationale to assert that the claimed
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`invention would have been obvious. See, e.g., Pet. 9 (“[V]ariations in
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`temperature and pressure are nothing more than the optimization of
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`oxidation conditions explicitly suggested by the ’732 publication . . .
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`Conducting routine experimentation to determine optimal or workable
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`ranges that produce expected results is suggested to one of ordinary skill in
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`the art by the ’732 publication.”).
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`It is well-established that “where the general conditions of a claim are
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`disclosed in the prior art, it is not inventive to discover the optimum or
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`workable ranges by routine experimentation.” In re Aller, 220 F.2d 454, 456
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`(CCPA 1955). However, the parameter to be optimized must have been
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`recognized by those skilled in the art to be a “result-effective variable.” In
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`re Antonie, 559 F.2d 618, 620 (CCPA 1977). “While the absence of any
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`disclosure regarding the relationship between the variable and the affected
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`property may preclude a finding that the variable is result-effective, the prior
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`art need not provide the exact method of optimization for the variable to be
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`result-effective.” In re Applied Materials, Inc., 692 F.3d 1289, 1297 (Fed.
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`Cir. 2012). Rather, “[a] recognition in the prior art that a property is affected
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`by the variable is sufficient to find the variable result-effective.” Id.
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`Moreover, where multiple result-effective variables are combined,
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`“[e]vidence that the variables interacted in an unpredictable or unexpected
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`way could render the combination nonobvious.” Id. at 1298 (citing KSR
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`Int’l Co. v. Teleflex Inc., 550 U.S. 398, 421 (2007)). Applying these
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`principles, we find that Petitioners have not demonstrated that it would have
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`been a matter of routine experimentation to optimize the reaction
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`temperature and pO2 as result-effective variables.
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`Petitioners contend that “the ’732 publication suggested to a person of
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`ordinary skill in the art to vary residence time, temperature and pressure to
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`within the claimed ranges, in order to maximize yield.” Pet. 9. Petitioners
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`assert that the ’732 publication discloses oxidation of HMF to FDCA with
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`Co/Mn/Br or Co/Mn/Zr/Br catalysts at a temperature range of about 50° to
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`250°C, most preferentially about 50° to 160°C, with a corresponding
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`pressure that keeps the acetic acid solvent mainly in the liquid phase. Id. at
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`30–31 (citing Ex. 1002, 7:2–5, 4:37–41, 15:7–9; Ex. 1009 ¶¶ 20, 86). In
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`particular, Petitioners point to the general disclosure that “[f]or preparation
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`of diacid, the preferred temperatures are about 50° to 250°C, most
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`preferentially about 50° to 160°C,” and that “[t]he corresponding pressure
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`is such to keep the solvent mostly in the liquid phase.” Id. at 9 (citing Ex.
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`1002, 7:2–7). Petitioners also point to the examples in the ’732 publication
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`showing reactions of HMF to FDCA at 150oC and at an air pressure of 1000
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`psi. Id. at 31 (citing Ex. 1002, 15–16; Ex. 1009 ¶ 20). As noted by
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`Petitioners, 1000 psi air pressure converts to approximately 14.5 bar pO2
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`when calculated using ~21% oxygen in air, and to 13.8 bar pO2 when
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`calculated using 20% oxygen in air. Id. at 33–34. Petitioners contend that
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`there is no evidence of a “patentable distinction (i.e., criticality) between the
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`claimed pO2 value 1–10 bar (properly construed up to 10.5 bar) and the prior
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`art 13.8 bar pO2 practiced in the ’732 publication, especially since the ’732
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`publication relies on reaction pressures for the same reason proffered by the
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`’921 patent,” i.e., “pressure of the reaction mixture is preferably selected
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`such that the solvent is mainly in the liquid phase.” Id. at 34 (citing Ex.
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`1001, 4:39–41).
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`Patent Owner argues that “[t]he cited prior art describes inefficient,
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`non-commercially viable processes and does not teach or suggest the
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`combination of temperature, oxygen partial pressure and catalyst operating
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`parameters of the ‘921 patent’s invention.” PO Resp. 1. With respect to the
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`’732 publication in particular, Patent Owner asserts that “the ‘732
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`publication’s process is done at higher pressure and the oxidation of HMF is
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`outside the temperature range recited in” the claims. Id. at 15. We are
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`persuaded by Patent Owner’s arguments and supporting evidence. Although
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`the ’732 publication teaches broadly a preferred temperature range of about
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`50° to 250°C (most preferentially about 50° to 160°C), it does not suggest
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`specifically keeping the temperature within the narrower range recited in
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`claims 1 and 7 (between 140 and 200°C) while also maintaining pO2
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`between 1 and 10 bar. The ’732 publication also teaches that “[t]he
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`preferred time of the reaction is determined by the temperature, pressure and
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`catalyst concentration such that a maximum yield of diacid is obtained.” Ex.
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`1002, 7:5–7. The reference also states that Table 4 “illustrates that
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`increasing catalyst concentrations at a given temperature and time, nearly
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`always increased the [FDCA] yield.” Id. at 15:9–11. However, contrary to
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`Petitioners’ optimization rationale, we find nothing in the ’732 publication
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`or the other cited prior art to suggest that adjusting both reaction temperature
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`and pO2 in the process could have predictably affected FDCA yields.
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`With respect to the claimed oxygen partial pressure range, we find
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`that the disclosure in the ’732 publication that “corresponding pressure is
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`such to keep the solvent mostly in the liquid phase” (see Ex. 1002, 7:4–5)
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`would not have led the skilled artisan to optimize pO2 to within the