PTAB

IPR2025-01471

Clean Chemistry Inc v. Enviro Tech Chemical Services Inc

Key Events

Petition

petition

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) at the point of use. The core claimed method involves introducing triacetin and aqueous hydrogen peroxide to water, mixing them to form a mixture, and then adding an aqueous alkali metal hydroxide to catalyze the reaction and produce PAA.

Prior Art Relied Upon: Okano (JP Publication # 2006-045147 A).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner asserted that Okano, particularly its Example 1, discloses all limitations of the challenged claims. Okano’s example details a batch process for creating a sterilizing PAA solution by first mixing triacetin (50g) and aqueous hydrogen peroxide (25g) with water (850g), and subsequently adding an alkaline aqueous solution containing sodium hydroxide. Petitioner contended this process directly maps to the sequential steps of independent claim 1. Petitioner further argued that Okano discloses or renders obvious the limitations of the dependent claims, including simultaneous or sequential introduction of reagents (claims 2-3), use of an aqueous stream and mixing vessel (claims 4-5), specific sodium hydroxide concentrations (claims 6-7), and reaction times sufficient to maximize conversion (claims 9-12). For claim 11, Petitioner calculated that the conversion percentage disclosed in Okano’s example falls within the claimed range of approximately 40.9% to 85.7%. For claims 13 and 14, Petitioner argued a POSITA would find it obvious to perform Okano's batch process on a continuous or intermittent basis to meet industrial demand for sterilization.

Prior Art Relied Upon: Okano (JP Publication # 2006-045147 A) and Withenshaw (WO 2001/046519).
Core Argument for this Ground:
- Prior Art Mapping: Petitioner argued that Okano teaches the core chemical method, while Withenshaw teaches an automated, continuous system for PAA generation that is ideal for implementing Okano’s chemistry on an industrial scale. Withenshaw’s system, which uses a batch make-up tank, pumps, and a downstream mixer for adding an alkali catalyst, explicitly discloses performing the PAA generation process on a continuous (claim 13) or intermittent (claim 14) basis.
- Motivation to Combine: A POSITA would combine Okano’s specific and effective batch chemistry with Withenshaw’s established continuous process system to achieve industrial scale, automation, and safety benefits. Both references are in the same narrow field of PAA generation. Petitioner argued a POSITA would be motivated to substitute Okano's liquid triacetin precursor for Withenshaw’s solid TAED precursor to avoid known issues with solid reagents, such as solubility and scum formation.
- Expectation of Success: Success was expected because the underlying base-catalyzed reaction is identical in both references, and Withenshaw’s system uses standard, adaptable components well-suited for Okano’s liquid reagents.

Prior Art Relied Upon: Okano (JP Publication # 2006-045147 A) and Oringer (Patent 3,432,546).
Core Argument for this Ground:
- Prior Art Mapping: This ground was asserted as an alternative argument specifically targeting claim 8, which recites performing the alkali addition step (d) simultaneously with the reagent introduction step (b). Oringer discloses a continuous reactor system where separate feed streams for the acetyl precursor, hydrogen peroxide, and alkaline catalyst are all introduced simultaneously into a mixer. Petitioner contended that implementing Okano’s chemistry using Oringer’s apparatus would result in the simultaneous mixing of all components.
- Motivation to Combine: A POSITA seeking to produce PAA continuously would look to known systems like Oringer's to implement the chemistry taught by Okano. Both references are directed to efficiently producing peracetic acid.
- Expectation of Success: Petitioner argued that modifying Oringer's apparatus to use Okano’s liquid triacetin instead of acetic anhydride would be a routine task for a POSITA, with a high expectation of successfully producing PAA.

Order of Steps: Petitioner contended that the plain language of claim 1 requires the method steps to be performed in the recited order. The argument relied on antecedent basis, noting the claim recites "providing water," then introducing reagents to "the water," then forming "a mixture," and finally adding alkali to "the mixture." This sequential language, Petitioner argued, mandates an ordered performance of the steps, which is critical to the direct mapping of Okano's sequential process.

Petitioner argued that discretionary denial would be inappropriate.
§314(a) (Fintiv): Petitioner asserted that the co-pending district court litigation is in a very early stage, with claim construction briefing just beginning and no substantive rulings or trial date set.
§325(d): Petitioner contended that denial under this section was unwarranted because the primary prior art reference, Okano, is highly material and was never submitted to or considered by the Examiner during prosecution. The prosecution history shows the Examiner only cited a parent patent to make an obviousness-type double patenting rejection.

Petitioner requested the institution of an inter partes review and the cancellation of claims 1-14 of Patent 9,363,997 as unpatentable.