PTAB

IPR2015-01838

Ei Du Pont De Nemous Co v. Furanix Technologies BV

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Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Method for the Preparation of 2,5-Furandicarboxylic Acid and for the Preparation of the Dialkyl Ester of 2,5-Furandicarboxylic Acid
  • Brief Description: The ’921 patent discloses a method for preparing 2,5-furandicarboxylic acid (FDCA) or its dialkyl ester. The method involves the liquid-phase catalytic oxidation of a furan-based derivative, such as 5-hydroxymethylfurfural (HMF), using an oxygen-containing gas in the presence of a cobalt, manganese, and bromine catalyst system within specific temperature and pressure ranges.

3. Grounds for Unpatentability

Ground 1: Claims 1-5 are obvious over the '732 publication, alone or in combination with RU '177 and the '318 publication.

  • Prior Art Relied Upon: '732 publication (WO 01/072732), RU '177 (USSR Patent Publication 448177A1), and '318 publication (Application # 2008/0103318).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that the '732 publication, which is admitted prior art in the ’921 patent, teaches the core of the claimed invention. It discloses oxidizing HMF to FDCA using a Co/Mn/Br/Zr catalyst in an acetic acid solvent. The '732 publication's preferred temperature range (up to 160°C) overlaps with the claimed range (140-200°C), and its exemplified oxygen partial pressure (~14.5 bar) is close to the claimed upper limit of 10 bar.
    • Motivation to Combine: The '732 publication expressly motivates a person of ordinary skill in the art (POSITA) to optimize reaction parameters, including temperature and pressure, to maximize yield. Petitioner contended that a POSITA would combine this teaching with RU '177 and the '318 publication, which disclose similar oxidation processes for furan derivatives at lower oxygen partial pressures (e.g., 2.1 to 6.4 bar in RU '177), well within the claimed 1-10 bar range. The motivation would be to optimize the process and reduce operational costs associated with high-pressure systems.
    • Expectation of Success: Because the prior art references describe analogous chemical reactions with the same class of starting materials, catalysts, and solvents to produce the same end product, a POSITA would have a reasonable expectation of success in applying the lower pressure conditions of RU '177 to the process of the '732 publication.

Ground 2: Claims 6 and 10 are obvious over the '732 publication in view of the '018 patent.

  • Prior Art Relied Upon: '732 publication (WO 01/072732) and '018 patent (Patent 8,558,018).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground targets dependent claim 6, which specifies the starting material is an ester of HMF. While the '732 publication teaches the base oxidation process, it uses HMF as the starting material. The '018 patent explicitly discloses processes for oxidizing HMF ester derivatives to form FDCA precursors using a similar Co/Mn/Br catalyst system.
    • Motivation to Combine: The '018 patent provides a clear motivation, explaining that using an HMF ester derivative offers significant advantages over using HMF directly, including easier purification and better solubility. A POSITA seeking to improve the '732 process would be motivated by '018's teachings to substitute the HMF starting feed with a more advantageous HMF ester.
    • Expectation of Success: Given that the '018 patent teaches the oxidation of the specific claimed reactant class (HMF esters) to produce the same final product (FDCA) under similar catalytic conditions, a POSITA would have a high expectation of successfully implementing this substitution in the '732 process.

Ground 3: Claims 1-4 are obvious over Partenheimer in view of the '732 publication and the '018 patent.

  • Prior Art Relied Upon: Partenheimer (a 2001 journal article), '732 publication (WO 01/072732), and '018 patent (Patent 8,558,018).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that Partenheimer alone discloses all elements of claim 1. It describes producing FDCA by oxidizing HMF with air using a Co/Mn/Br catalyst in acetic acid. The disclosed reaction conditions—temperature up to 125°C and oxygen partial pressure of ~14.5 bar—are close to the claimed ranges.
    • Motivation to Combine: Partenheimer explicitly states that "yield increases with...temperature," providing a direct motivation for a POSITA to increase the reaction temperature from 125°C into the claimed 140-200°C range to improve results. This is reinforced by similar teachings in the '732 publication. The '018 patent further teaches conducting such oxidations at pressures that overlap the claimed 1-10 bar range, motivating the adjustment of Partenheimer's pressure.
    • Expectation of Success: A POSITA would have a high expectation of success, as Partenheimer's own data and statements suggest that increasing temperature is a routine and predictable way to optimize the yield of FDCA.
  • Additional Grounds: Petitioner asserted additional obviousness challenges, including that claims 7-9 are obvious over the '732 publication in view of Applicants' Admitted Prior Art and publications like Lewkowski or Oae, which establish the known practice of esterifying FDCA. Petitioner also argued that claim 1 is obvious over RU '177 alone.

4. Key Claim Construction Positions

  • "comprising": Petitioner argued that this transitional phrase, used for the method steps and catalyst composition, should be given its ordinary open-ended meaning. This construction means that prior art processes that include additional steps or catalyst components still meet the claim limitations, as long as they contain all the recited elements.
  • "at an oxygen partial pressure of 1 to 10 bar": Petitioner argued this phrase should be interpreted to mean "about 1 to about 10 bar" and encompass values close to the stated range. This construction is supported by the patent's own examples (disclosing 10.5 bar) and is critical to their argument that prior art pressures like ~14.5 bar are close enough to render the claimed range obvious.

5. Relief Requested

  • Petitioner requests the institution of an inter partes review and the cancellation of claims 1-10 of the ’921 patent as unpatentable under 35 U.S.C. §103.