DETAILED ACTION
Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Upon further review, the restriction requirement made on February 04, 2026, is vacated. Claims 29-62, in their entirety, are under examination.
Objection
The specification is objected to because the title of the invention, “process,” is non-descriptive. Appropriate correction is required.
Claim Rejections - 35 USC § 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis (i.e., changing from AIA to pre-AIA ) for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 29-62 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al (CN 109956970) in view of Saudan et al US 2008/0071121 A1).
Applicants’ claimed invention is directed to a process for hydrogenation of an ester-containing substrate, comprising treating an ester-containing substrate with a base and a transition metal catalyst in the presence of molecular hydrogen, wherein the base is present in at least 30 mol% based upon the total amount of ester-containing substrate and wherein the substrate/catalyst loading is greater than or equal to 10,000/1.
Regarding claim 29, Wang discloses the hydrogenation of ester substrate using transition metal catalysts and a base in the presence of molecular hydrogen. while Wang provides the general reaction framework (abstract), Saudan teaches that useful quantities of base in such systems range from 5 to 5000 molar equivalents relative to the catalyst complex [0099].
It would have been obvious to one of ordinary skill in the art, prior to the effective filing date of the claimed invention to arrive at the present claim, at least 30 mole % base (relative to substrate) because, when operating at the claimed substrate/catalyst loading of 10,000:1, this concentration quates to 3,000 molar equivalents of base relative to the catalyst. As 3000 equivalents falls directly within the useful range disclosed by Saudan, the selection of this specific amount represents a routine optimization of known reaction parameters. A practitioner would be motivated to use these higher base levels to ensure catalyst activation and reaction stability at high industrial dilutions suggested by Saudan, yielding the expected result of efficient ester conversion.
Regarding claims 30-33, while these claims narrow the base concentration to 35% to 50 mole% corresponds to 3,500-5000 molar equivalents relative to the catalyst. This falls directly within the upper limit of the useful quantities (up to 5000 equivalents) explicitly disclosed by Saudan in paragraph [0099]. It would have been obvious to one of ordinary skill in the art, prior to the effective filing date of the claimed invention to operate at these higher concentrations to prevent catalyst deactivation or to drive the reaction equilibrium toward the desired alcohol product, especially when using the high dilution ratios suggested by Saudan. The selection of a value within a known, disclosed range is a matter of routine optimization rather than an inventive step, as the result is predictable improvement in reaction kinetics.
Regarding claims 34-36, Wang teaches Non-limiting examples of the base used in the catalytic hydrogenation of the ester compound of the present invention are sodium methoxide, sodium ethoxide, sodium isopropoxide, sodium t-butoxide, potassium methoxide, potassium ethoxide, potassium isopropoxide, potassium t-butoxide and the like. The base used can be added directly to the inner tube of the reaction vessel or dissolved in the corresponding solvent and added to the inner tube of the reaction vessel. See page 8, 4th paragraph.
Regarding claims 37-39, Wang teaches the catalytic hydrogenation of the ester compound of the present invention can be carried out without a solvent, but a solvent is preferably used. Non-limiting examples of the solvent to be used are one or a mixed solvent of one or more of organic solvents such as tetrahydrofuran, toluene, methanol, and 1,4-dioxane. See page 8, 3rd paragraph.
Regarding claims 40-44, while Wang’s specific laboratory examples in Tables 1 and 2 (original document) utilizes higher solvent concentration, the use of a solvent is a result-effective variable well-knows to those in the art. Wang uses THF, methanol and various other solvent in the process. It would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention to reduce the solvent volume to the claimed 10-100 vol% range to achieve a more concentrated reaction. Such a modification is a routine optimization aimed at increasing volumetric productivity and minimizing solvent waste in industrial applications, as suggested by the large-scale efficiency goals taught in Saudan. Since the claimed range is merely a lower dilution of the same chemical system disclosed by Wang, it represents a predictable choice among known process parameters.
Regarding claims 45 and 46 are rejected as unpatentable over Wang in view of Saudan, as Wang’s disclosed temperature (60-100 0C) and pressure (3-10 MPa) fall within the claimed ranges. These parameters optimized for ester hydrogenation, establish a prima facie of obviousness. See page 8, 2nd paragraph.
Regarding claims 47-50, while Wang suggests a catalyst loading of 0.1 to 10 mole% (corresponding to S/C ratios of 10/1 to (1000/1), Saudan explicitly directs the skill artisan toward higher industrial efficiencies. Saudan teaches that these ester hydrogenation systems are active at S/C ration of 10,000/1 and higher. It would have been obvious to arrive at the claimed loading of 20,000/1 to 100,000/1 because Saudan discloses that the useful quantities of base (up to 5,000 molar equivalents relative to the catalyst) are specifically designed to maintain activity at such high dilution. Achieving a loading of 100,000/1 is merely the logical extension of the efficiency goals taught by Saudan [0099], representing a predictable increase in turnover number based on the highly active catalytic frameworks disclosed in both references.
Regarding claim 51, this claim is rendered obvious by Wang, which explicitly teaches a method for hydrogenating ester compounds using a biphenyl type tridentate ligand ruthenium complex (page 8, 3rd paragraph). Because Wang specifically identifies the use of a tridentate ligand, a ligand that binds to the metal center at three coordination sites, the structural requirement of claim 51 is clearly disclosed in the primary reference.
A person ordinary skill in the art would be motivated to use the tridentate ligands of Wang in the high loading processes suggested by Saudan because tridentate architectures often provide the enhanced thermal stability and rigidity necessary to achieve the high turnover number and S/C loading (10,000/1 to 100,000/1) recited in the preceding claims. The use of a tridentate ligand is therefore a predictable choice of a known catalytic structure to achieve the efficiency goals established by the combined prior art.
Regarding claims 52-56, Wang explicitly discloses a library of tridentate ligand (pages 2-4,6 and 7-8 original Chinese document) featuring various substitution pattern on the ligand scaffold to tune the electronic and steric properties of the ruthenium complex. These substituents include various alkyl, aryl, and functional groups intended to optimize catalytic performance. Simultaneously, Saudan teaches that the specific architecture of the ligand (whether the bidentate ligands listed on page 3 and 5 or related pincer-type ligands) is a variable that the efficiency in ester hydrogenation.
It would have been obvious to a person of ordinary skill in the art, prior to the effective filing date of the claimed invention to arrive at the specific substituted tridentate ligands of claims 52-56 because Wang provides a clear roadmap for varying these substituents within a known tridentate framework. Choosing a specific substituent from the broad verities disclosed in Wang is matter of routine experimentation aimed at maximizing the catalyst’s stability and turnover number at the high substrate/catalyst (S/C) loadings (up to 100,000/1) suggested by Saudan. Since the prior art describes these substituents as a standard means of modifying catalyst behavior, the claimed ligands represent a predictable selection from a finite number of identified possibilities with a reasonable expectation of success.
Claim 57 defines the ester substrate, where R6 and R7 are broad organic group (1-70 carbons) or form a ring. This encompasses a vast range of esters, including lactones (cyclic esters). Wang explicitly discloses the hydrogenation of various organic ester (e.g., 4-MeC6H14COOMe), which fall squarely within the R6/R7 range defined in claims. See original Chinese Document, Tables 1 and 2).
Furthermore, Saudan teaches that the catalytic system is broadly applicable to a wide variety of esters (Table III), including those where R groups part of the organic groups having 1-70 carbon atoms.
It would have been obvious to a person of ordinary skill in the art to apply the catalytic process to the substrates of claim 57 because both Wang and Saudan establish that the transition metal/base system is a versatile method for hydrogenation across a wide homologous series of esters. Selecting a substrate with 1 to 70 carbon atoms or a cyclic structure represents the use of a known reaction for its intended purpose on a predictable range of analogues compounds.
Regarding claim 58, Wang explicitly list methyl acetate, methyl benzoate, ethyl acetate, methyl levulinate as non-limiting examples of suitable substrate (page 7, last paragraph). Because these examples are standard, commercially available options, selecting then in combination with the high loading process of Saudan constitutes a predictable variation.
Regarding claim 59, while Wang does not explicitly use the term batch process, all experimental examples (e,g., Table 2,3 mmol scale) describe charging a reaction vessel with a substrate, catalyst, and base, then subjecting the mixture to hydrogen pressure for a set time (1-64 hours) before recovering the product. This sequence of operations defines a standard batch process.
Regarding claim 60, the motivation to utilize a batch process and base recycling stems from the inherent drive to improve industrial scalability and process economics. While Wang establishes the chemical transformation, a person ordinary skill in the art would find it obvious to apply batch operations as a standard engineering choice for high-pressure hydrogenations. Furthermore, since Saudan teaches the necessity of high base concentrations for catalyst activation at industrial dilutions, the motivation to recycle that excess base is a routine cost reduction strategy amid at minimizing reagent waste and maximizing volumetric productivity.
Regarding claims 61 and 62, while Wang demonstrate the reaction in batch-like laboratory settings, Saudan explicitly discusses industrial efficiency and high catalytic productivity. It would have been obvious to a person of ordinary skill in the art to conduct this reaction as a flow process (continuous flow) and to recycle the excess base, as these are standard chemical engineering techniques used to improve space-time yield and safety in high pressure hydrogenations. Transitioning from batch to flow is a routine optimization aimed at achieving consistent product quality and reducing the footprint of the reactor, while recycling the base, which Saudan teaches is necessary in high molar equivalents is a predictable cost reduction strategy to enhance the overall process economy.
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/JAFAR F PARSA/Primary Examiner, Art Unit 1692
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