PTAB

IPR2025-01472

Clean Chemistry Inc v. Enviro Tech Chemical Services Inc

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Key Events
Petition
petition

1. Case Identification

2. Patent Overview

  • Title: Methods and Compositions for the Generation of Peracetic Acid on Site at the Point-of-Use
  • Brief Description: The ’449 patent describes methods for generating non-equilibrium solutions of peracetic acid (PAA) by reacting a hydrogen peroxide-triacetin solution with an aqueous source of an alkali metal hydroxide in water.

3. Grounds for Unpatentability

Ground 1: Obviousness over Okano - Claims 1-7 and 9-22 are obvious over Okano.

  • Prior Art Relied Upon: Okano (JP 2006-045147 A).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Okano, a reference not considered during prosecution, discloses all limitations of the challenged claims. Okano’s Example 1 teaches a method of preparing a sterilizing cleaner by mixing triacetin and hydrogen peroxide with water, and then adding an alkaline aqueous solution (sodium hydroxide) to form a mixture, which generates a non-equilibrium PAA solution. Petitioner contended that Okano’s disclosure of a premixed “first composition” containing triacetin and hydrogen peroxide with limited water content for stability meets the claimed limitation of “introducing a hydrogen peroxide-triacetin solution.” Petitioner further argued that dependent claims are obvious because Okano teaches the claimed component ratios, concentrations, reaction times, and process parameters (e.g., use in a continuous or intermittent basis for industrial cleaning, and stabilization with acid).

Ground 2: Obviousness over Okano and Withenshaw - Claims 1, 4-5, 14-16, and 18 are obvious over Okano in view of Withenshaw.

  • Prior Art Relied Upon: Okano (JP 2006-045147 A) and Withenshaw (WO 2001/046519).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner asserted that this combination renders the claims obvious by implementing Okano’s batch chemistry using Withenshaw’s disclosed continuous process system. Withenshaw teaches a “Peroxyacid Delivery Process” for the continuous, on-site generation of PAA. The system uses a batch make-up tank fed with water, an acetyl-precursor, and hydrogen peroxide, which is then mixed with an alkaline material in a tubular reactor. This combination explicitly teaches performing the steps on a continuous basis (claim 14), in a mixing tank (claim 5), using an aqueous stream (claim 4), for immediate point-of-use application (claims 16 and 18).
    • Motivation to Combine: A POSITA would combine Okano’s preferred triacetin-based chemistry with Withenshaw’s continuous generation system to automate and scale up the PAA production process. This combination would achieve desirable industrial features taught by Withenshaw, such as improved safety, low capital cost, short residence time, and the benefits of on-site generation for the applications described in Okano.
    • Expectation of Success: A POSITA would have a reasonable expectation of success because both references are directed to the same alkaline-catalyzed reaction to produce PAA and employ standard, well-established chemical process equipment. Substituting Okano’s liquid triacetin solution for Withenshaw’s solid acetyl-precursor (TAED) would be a simple modification.

Ground 3: Obviousness over Okano and Oringer - Claim 8 is obvious over Okano in view of Oringer.

  • Prior Art Relied Upon: Okano (JP 2006-045147 A) and Oringer (Patent 3,432,546).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground specifically addresses claim 8, which requires that step (d) (adding the alkali hydroxide) is performed simultaneously with step (b) (introducing the hydrogen peroxide-triacetin solution). Petitioner argued that while this contradicts the required step order of claim 1, if the claim is considered valid, the combination with Oringer renders it obvious. Oringer discloses a method and apparatus for the continuous manufacture of PAA using a tubular reactor where reagent feed streams, including an alkaline catalyst, are simultaneously introduced into a mixer with a water feed stream.
    • Motivation to Combine: A POSITA seeking to implement Okano’s chemistry in a continuous process would look to analogous systems like Oringer. Oringer provides a well-known apparatus for continuously producing PAA that involves simultaneous mixing of reagents, directly suggesting the limitation of claim 8.
    • Expectation of Success: A POSITA would have a high expectation of success in implementing Okano’s chemistry in Oringer’s system, as both use standard reactants and well-established chemical engineering principles for generating PAA.

4. Key Claim Construction Positions

  • Method Steps Must Be Performed in Order: Petitioner argued that for claim 1, the language requires the steps to be performed in the recited order (a through e). This is based on antecedent basis, where each subsequent step refers to a product of a prior step (e.g., step (c) mixes “the hydrogen peroxide-triacetin solution” from step (b) with “the water” from step (a) to form “a mixture,” which is then acted upon in step (d)). Petitioner contended that claim 8, which recites performing step (d) simultaneously with step (b), cannot be reconciled with the plain language of claim 1.

5. Arguments Regarding Discretionary Denial

  • Petitioner argued against discretionary denial under §314(a) and §325(d). It was asserted that this is the first IPR filed against the ’449 patent and that the co-pending district court litigation is in its earliest stages, with no claim construction rulings issued. Furthermore, Petitioner argued that the petition raises new invalidity questions because it relies primarily on Okano, a prior art reference that was not considered by the Examiner during the original prosecution and is not cumulative of the art of record.

6. Relief Requested

  • Petitioner requests institution of an inter partes review and cancellation of claims 1-22 of Patent 8,546,449 as unpatentable under 35 U.S.C. §103.