Clean Chemistry, Inc. v. Enviro Tech Chemical Services, Inc.

1. Case Identification

• Case #: IPR2025-01471
• Patent #: 9,363,997
• Filed: September 2, 2025
• Petitioner(s): Clean Chemistry, Inc.
• Patent Owner(s): Enviro Tech Chemical Services, Inc.
• Challenged Claims: 1-14

2. Patent Overview

• Title: Methods and Compositions for the Generation of Peracetic Acid on Site at the Point-of-Use
• Brief Description: The ’997 patent discloses methods for generating non-equilibrium solutions of peracetic acid (PAA). The methods involve introducing triacetin and aqueous hydrogen peroxide to water, mixing them, and then adding an aqueous source of an alkali metal hydroxide to initiate the reaction.

3. Grounds for Unpatentability

Ground 1: Obviousness over Okano - Claims 1-7 and 9-14 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, particularly its Example 1, discloses every limitation of the challenged claims. Independent claim 1 recites a five-step method: (a) providing water, (b) introducing triacetin and aqueous hydrogen peroxide to the water, (c) mixing to form a mixture, (d) adding an alkali metal hydroxide to the mixture, and (e) forming a PAA reaction medium. Petitioner asserted that Okano’s Example 1 expressly details these steps in the same sequence: mixing 50g of triacetin and 25g of hydrogen peroxide with 850g of water, and then pouring in an aqueous solution of sodium hydroxide and stirring for 5 minutes. Petitioner further contended that Okano’s general disclosures and specific examples teach the limitations of the dependent claims, including simultaneous (claim 2) or sequential (claim 3) introduction of reagents, specific sodium hydroxide concentrations (claims 6-7), and reaction times (claims 9-10).
  • Expectation of Success: As a single-reference ground, Petitioner asserted that a person of ordinary skill in the art (POSITA) would find it obvious to practice the method disclosed in Okano, as all elements are present in that single reference.

Ground 2: Obviousness over Okano and Withenshaw - Claims 1, 4, 5, and 13-14 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 argued that Okano teaches the core chemical process as established in Ground 1, while Withenshaw teaches a system for the continuous generation of PAA. Withenshaw discloses a "Peroxyacid Delivery Process" that involves feeding water, an acetyl precursor, and hydrogen peroxide into a make-up tank, then mixing this solution with an alkaline material (sodium hydroxide) in an in-line mixer to continuously produce PAA. This combination allegedly teaches performing Okano's batch method on a continuous (claim 13) or intermittent (claim 14) basis using standard industrial equipment like aqueous streams (claim 4) and mixing tanks (claim 5), as disclosed by Withenshaw.
  • Motivation to Combine: A POSITA would combine Okano and Withenshaw to automate and scale up Okano’s laboratory-scale batch process for industrial applications. Withenshaw provides a well-suited system for implementing Okano’s chemistry continuously. Further motivation would stem from replacing Withenshaw’s solid, agglomerated acetyl precursor (TAED), which has known solubility and side-reaction issues, with Okano’s more desirable liquid triacetin precursor.
  • Expectation of Success: A POSITA would have a high expectation of success because both references are in the same field, employ the same base-catalyzed PAA generation chemistry, and the combination involves substituting a known liquid reactant for a solid one in a standard, adaptable continuous process system.

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 was presented as an alternative argument, contingent on the Patent Owner's potential interpretation that the steps of claim 1 need not be performed in order. Claim 8 recites performing step (d) (adding hydroxide) simultaneously with step (b) (adding precursors). Petitioner argued that Oringer discloses an apparatus for the continuous manufacture of PAA where reactants, including an acetyl precursor, hydrogen peroxide, and an alkaline catalyst, are simultaneously fed from separate tanks into a mixer and tubular reactor.
  • Motivation to Combine: A POSITA would be motivated to implement Okano's specific chemistry (using triacetin as the acetyl precursor) within Oringer’s established apparatus for continuous, simultaneous mixing. Both references are directed to efficiently producing PAA using similar underlying chemistry.
  • Expectation of Success: Success would be expected as the combination merely involves using Okano's preferred reactants within Oringer's known and suitable manufacturing apparatus.

4. Key Claim Construction Positions

• Petitioner asserted that the steps of claim 1 must be performed in the recited order. The argument relied on antecedent basis, where the use of definite articles like "the water" in step (b) and "the mixture" in step (d) grammatically and logically requires the prior completion of the steps that define those terms (step (a) and step (c), respectively). This construction is central to Petitioner’s primary argument that Okano’s sequential process maps directly to claim 1 and that claim 8, which recites simultaneous actions, is inconsistent with claim 1.

5. Arguments Regarding Discretionary Denial

• Petitioner argued against discretionary denial under Fintiv factors, stating that the co-pending district court litigation is in a very early stage, with no claim construction rulings issued.
• Petitioner also argued that denial under 35 U.S.C. §325(d) is inappropriate because the primary reference, Okano, is highly material and was never submitted to or considered by the Examiner during prosecution. The only reference cited by the Examiner was a parent patent used for a double-patenting rejection.

6. Relief Requested

• Petitioner requests institution of an inter partes review and cancellation of claims 1-14 of the ’997 patent as unpatentable.