PTAB

IPR2018-01768

Hubei Grand Life Science and Technology Co., Ltd. v. Vitaworks IP, LLC

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1. Case Identification

2. Patent Overview

  • Title: Process for Producing Taurine
  • Brief Description: The ’890 patent discloses a process for producing taurine via the ammonolysis of alkali isethionate. The purported novelty lies in conducting the reaction in the presence of its known byproducts, alkali ditaurinate or alkali tritaurinate, to allegedly inhibit further byproduct formation and increase overall taurine yield.

3. Grounds for Unpatentability

Ground I: Claims 1 and 3-10 are obvious over Liu 2013 in view of DD 023

  • Prior Art Relied Upon: Liu 2013 (a journal article titled "Process Design of Taurine Ammonolysis") and DD 023 (a 1985 German patent).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Liu 2013 discloses all elements of the claimed process. Liu describes producing taurine via ammonolysis of sodium isethionate, followed by neutralization with sulfuric acid and solid-liquid separation—mapping directly to steps (b), (c), and (d) of claim 1. For step (a), Liu teaches that after initial taurine separation, the remaining "mother liquor" contains byproducts, including sodium ditaurinate. Liu explicitly states that this mother liquor can be recycled to "participate again in ammonolysis," and if the sodium ditaurinate is "fed again into the ammonolysis reaction, the yield of taurine would increase." This, Petitioner asserted, is a direct teaching of mixing alkali isethionate with a solution of alkali ditaurinate before ammonolysis. DD 023 was cited to corroborate that ditaurinate and tritaurinate are well-known, inherent byproducts of this specific reaction. Dependent claims are also taught, as Liu discloses using sulfuric acid (claim 4), sodium hydroxide as a catalyst (claim 6), and achieving yields up to 95% (claims 7, 9, and 10).
    • Motivation to Combine: A Person of Ordinary Skill in the Art (POSA) would combine these references to solve the known problem of improving taurine yield, the same objective stated in the ’890 patent. Liu provides a clear motivation by teaching that recycling the ditaurinate-containing mother liquor is a method to increase the overall process yield.
    • Expectation of Success: A POSA would have a high expectation of success. The ammonolysis process is well-established. Petitioner contended that applying Le Châtelier's Principle—predicting that adding a byproduct (ditaurinate) to the starting materials will drive the reaction equilibrium toward the desired product (taurinate)—is basic, predictable chemistry. Liu's own disclosure of achieving a 95% yield confirms the viability and predictability of this approach.

Ground II: Claims 1 and 3-10 are obvious over Wu 2004 in view of DD 023 and Liu 2013

  • Prior Art Relied Upon: Wu 2004 (a journal article titled "Optimization on Ammonolysis in Manufacturing Method of Taurine"), DD 023 (a 1985 German patent), and Liu 2013 (a 2013 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: Petitioner argued that Wu 2004 provides an even stronger teaching than Liu. Wu discloses the same ammonolysis process and identifies ditaurinate as a byproduct of a "side reaction." Wu expressly teaches that after taurine separation, the resulting byproducts, "consisting primarily of [ditaurinate]," can be "fed again into the ammonolysis system," causing the total yield of taurine to "very well increase" to over 97%. This teaches the core inventive concept. Wu also discloses using sodium carbonate as a catalyst (claim 6) and sulfuric acid for neutralization (claim 4). DD 023 was again used to confirm the identity of the byproducts, while Liu was added to supplement teachings on the cyclic nature of the process.
    • Motivation to Combine: The motivation is clear: process optimization. A POSA seeking to maximize taurine yield would be directly motivated by Wu's explicit disclosure that recycling ditaurinate can increase the yield to over 97%, along with Wu's experimental data showing how to optimize reaction conditions.
    • Expectation of Success: A POSA would have reasonably expected success because Wu not only suggests the method but quantifies the successful outcome, with yields (up to 97.6%) that meet and exceed those recited in dependent claims 7, 9, and 10. The combination represents a straightforward application of disclosed optimization techniques.

Ground III: Claims 1 and 3-10 are obvious over Chen in view of DD 023 and Wu 2004

  • Prior Art Relied Upon: Chen (Application # 2014/0121405), DD 023 (a 1985 German patent), and Wu 2004 (a 2004 journal article).
  • Core Argument for this Ground:
    • Prior Art Mapping: This ground was framed to overcome the prosecution history, where the Examiner had relied on Chen. Petitioner argued that Chen discloses two cyclic processes for taurine synthesis that both include the fundamental ammonolysis of sodium isethionate step. In these cyclic processes, mother liquor is recycled. Petitioner contended that a POSA would know this recycled liquor inherently contains the ammonolysis byproducts (ditaurinate and tritaurinate, confirmed by DD 023). While Chen teaches recycling, Wu provides the explicit teaching of why and how to do so for yield optimization. Wu's disclosure that recycling ditaurinate boosts yield to >97% provides the missing piece that the Patent Owner argued was absent from Chen alone.
    • Motivation to Combine: A POSA would be motivated to improve the cyclic processes taught in Chen by applying the specific optimization strategies disclosed in Wu. Since Chen's process already involves recycling, applying Wu's teachings on what is in the recycled liquor and why its reuse is beneficial would be a logical and predictable step for process improvement.
    • Expectation of Success: A POSA would have a high expectation of success in combining the teachings. The combination amounts to applying a known optimization technique (recycling specific byproducts, per Wu) to a known process framework (the cyclic synthesis in Chen) to achieve a predictable result (improved yield).

4. Relief Requested

  • Petitioner requested institution of an inter partes review and cancellation of claims 1 and 3-10 of Patent 9,573,890 as unpatentable.