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 .
Response to Arguments
Applicant's 1/28/26 arguments vis-a-vis 35 U.S.C. 112, simply stating that the rejections were addressed by the 1/28/26 amendments canceling the so-rejected claims, have been fully considered and are persuasive. Said rejections are mooted by said amendments.
Applicant's 1/28/26 arguments vis-a-vis prior art rejections employing Rayner et al., US 2017/0001142 (published 1/5/17) (“Rayner”) in view of the 2015 Park et al. article (“Park”) (herein collectively “R/P”) as the primary references therefor, stating in pertinent part that employing a polar aprotic solvent(s) with the switchable ionic liquid enables a lower viscosity of the latter when comprising absorbed gas as compared to in the absence of a polar aprotic solvent, which “affords an unexpected reduction in energy costs in removing acid gases from a gaseous mixture”, have been fully considered but are not persuasive. The quoted argument, which is considered to be an assertion of unexpected results and/or criticality of employing a polar aprotic solvent(s) as claimed, cannot by itself overcome the obviousness conclusion of record, as the use/presence of a polar aprotic solvent as claimed is anticipated by Rayner, even though Rayner only renders the claim prima facie obvious overall. See MPEP 716.01(b), citing In re Kao, 639 F.3d 1057, 1068 (Fed. Cir. 2011) (stating that “Where the offered secondary consideration actually results from something other than what is both claimed and novel in the claim, there is no [requisite] nexus to the merits of the claimed invention.”) (emphasis Examiner’s). Said rejections, adjusted as necessitated by the 1/28/26 amendments, are re-asserted as proper.
Applicant's 1/28/26 arguments vis-a-vis prior art rejections over R/P further in view of the 2008 Heldebrant et al. Energy Environ. Sci. article (“Heldebrant”), simply stating that the rejections “should be reconsidered for the reasons set forth above” vis-à-vis R/P, have been fully considered but are not persuasive for the same reasons as those detailed above. Said rejections, adjusted as necessitated by the 1/28/26 amendments, are re-asserted as proper.
Information Disclosure Statement (“IDS”)
The 1/23/26 IDS fails to comply with 37 CFR 1.98(a)(3)(i) because it does not include a concise explanation of the relevance, as it is presently understood by the individual designated in 37 CFR 1.56(c) most knowledgeable about the content of the information, of each non-English-language reference listed. The IDS has been placed in the application file, but the CN106457125 reference listed therein has not been considered. Notwithstanding applicant’s statement “see US20170081604” in ‘125’s citation line/row, ‘604 was not, contrary to the requirements of 37 CFR 1.98(a)(1) and MPEP 609.04(a)I. (par. 2-3), “listed in a section separately from citations of other documents.” (i.e. ‘604 was required to be listed apart from the “Foreign Patent Documents” section, in the “U.S. “Patent Application Publications” section)1. Should applicant wish to correct this deficiency in a subsequent IDS by filing i) an English equivalent document, English translation, or concise explanation of the relevance of ‘125, and/or ii) a proper citation of ‘604, MPEP 609.05(a) states that “the date that the new IDS or correction is filed will be the date of the IDS for purposes of determining compliance with the requirements based on the time of filing of the IDS (37 CFR 1.97)."
Claim Rejections - 35 USC § 103
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 of this title, 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 set forth in Graham v. John Deere Co., 383 U.S. 1, 148 USPQ 459 (1966), that are applied 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.
This application currently names joint inventors. In considering patentability of the claims the Examiner presumes that the subject matter of the various claims was commonly owned as of the effective filing date of the claimed invention(s) absent any evidence to the contrary. Applicant is advised of the obligation under 37 CFR 1.56 to point out the inventor and effective filing dates of each claim that was not commonly owned as of the effective filing date of the later invention in order for the Examiner to consider the applicability of 35 U.S.C. 102(b)(2)(C) for any potential 35 U.S.C. 102(a)(2) prior art against the later invention.
In considering the obviousness rejections below, the applicant should note that the person having ordinary skill in the art at the time of the effective filing date of the claimed invention has the capability of understanding the scientific and engineering principles applicable to the claimed invention. The references of record in the application reasonably reflect this level of skill.
Claims 1, 3-5, 12, and 14-19 are rejected under 35 U.S.C. 103 as being unpatentable over Rayner et al., US 2017/0001142 (published 1/5/17) (“Rayner”) in view of the 2015 Park et al. article (“Park”). Regarding claims 1, 3-5, and 12, Rayner teaches a method comprising absorbing an acid gas from a mixed gas (flue gas stream 3) by counter-currently contacting the mixed gas with a solvent system (in absorber unit 1) such as tetrabutylammonium acetate (“TBAA”) in sulfolane (viscosity @ 25oC = 10.07 cP; BP = 285oC)2 to give a lean gas 4 and an enriched solvent comprising acid gas sorbed therein (stream exiting the bottom of 1), regenerating the solvent system by flash-removing absorbed acid gas therefrom (in flash desorbers 2) to an give acid gas stream and a regenerated solvent, the latter being recycled to the (top of the) absorber 1. See Rayner at, e.g., par. 5, 124, and 142-43; Figs. 1 & 6; Table 5. While Rayner’s solvent system is a ‘conventional’ ionic liquid (see Park at, e.g., pp. 2-4 (“Liquids (ILs)” and “Conventional Ionic Liquids”); Scheme 1) rather than a switchable ionic liquid, defined per p. 6, ln. 14-17 of the specification-as-filed as “easily decomposable at moderate temperatures [to] regenerat[e] the [ionic liquid’s] precursors and releasing [ ] absorbed acid gas”, this limitation is taught by Park.
Park teaches that (conventional) ILs such as Rayner’s TBAA (see Park at, e.g., pp. 2-4 (“Liquids (ILs)” and “Conventional Ionic Liquids”); Scheme 1), as well as CO2BOLs (defined as “organic liquids consisting of an alcohol and a strong amidine or guanidine base that can chemically capture CO2 to form amidinium or guanidinium respectively”) such as DBU in conjunction with an alcohol (herein “DBU-ROH”) or TMG in conjunction with an alcohol (“TMG-ROH”), are effective in CO2 removal methods. See id. at, e.g., pp. 7-9 (“CO2-Triggered Switchable Solvents” and “CO2-Binding Organic Liquids”); Scheme 3. Given the foregoing, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify Rayner’s overall methodology by replacing its TBAA IL with a CO2BOL such as DBU-ROH or TMG-ROH as taught by Park, given Park’s teaching of the effectiveness/interchangeability of TBAA, DBU-ROH, and TMG-ROH for CO2 sorption methods (such as Rayner’s) - selecting between two or more materials or processes is an obvious choice if their equivalence for the given purpose was known in the art when the invention was made. See MPEP 2144.06 II. Further, "[a]n express suggestion to substitute one equivalent component or process for another is not necessary to render such substitution obvious." Id., citing In re Fout, 675 F.2d 297 (CCPA 1982).
Regarding claim 14, Rayner heats (i.e. to a desired T) its enriched solvent in unit 11 downstream of its absorber 1 but upstream of its flash desorbers 2; the heating is considered to also expand the enriched solvent (i.e. to a desired P) as P varies directly with T via the well-known chemical equation PV=nRT. See Rayner at, e.g., par. 142; Fig. 6.
Regarding claim 15, Rayner’s pre-desorption heating is accomplished via heat exchange with an external fluid in unit 11 (see id.); this heating is considered a “second” heating step regardless of whether a previous heating step was conducted, since the claim indicates that the “first heating step” “and/or” the “second heating step” will meet the claim.
Regarding claim 16, while Rayner does not teach a specific example where i) the regenerated solvent releases heat to the enriched solvent (i.e. via heat exchange) and ii) a second cooling step upstream of the absorber 1, it nevertheless would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to do so. Regarding i), heat exchanging hot regenerated solvent with cold enriched solvent is a conventional prior art step; Rayner describes it as such and includes multiple examples thereof, rendering it prima facie obvious to do so. See id. at, e.g., par. 5, 85-86, and 95; Figs. 1 and 10. Regarding ii), in conducting said prima facie obvious heat exchanging, Rayner’s cooling unit 5 performs a “second cooling step” as claimed. See id. at, e.g., par. 5 and 146; Figs. 1 & 6.
Regarding claim 17, in conducting the prima facie obvious heat exchange between hot regenerated solvent and cold enriched solvent as detailed above, it further would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to conduct this heat exchange downstream of Rayner’s heating/expansion unit 11 (the arrangement -or re-arrangement- of prior art parts is a prima facie obvious variation; see MPEP 2144.04 VI.C.), and conduct an additional heating step downstream of said heat exchange but upstream of Rayner’s flash desorbers 2, as it is also prima facie obvious to duplicate prior art parts (such as Rayner’s heating/expansion unit 11) in addition to arranging them as desired. See the duplication of prior art parts has been held to be an obvious variation3.
Regarding claim 18, as this claim is regarded to merely duplicate Rayner’s absorber 1 and cooling unit 5, which would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention as detailed above4, and conduct its absorption step a second time (with a portion of its enriched solvent after a prima facie cooling in duplicated cooler 5 since gases are more soluble in cold liquids), this additional absorption step is also considered prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention - it is “well within the expected skill of the technician to operate a process continuously [or thus, repeatedly]." See, e.g., In re Dilnot, 319 F.2d 188, 138 USPQ 248, 252 (CCPA 1963) (internal citations omitted) and In re Citron, 140 USPQ 220, 222 (CCPA 1964) (affirming BPAI’s upholding of Examiner’s rejection of claims repeating prior-taught steps as obvious); MPEP 2144.04 V.E.
Regarding claim 19, as Rayner teaches that its method is appropriate for natural gas purification (see Rayner at, e.g., par. 42, 99, and 102), it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to recover natural gas hydrocarbons dissolved in Rayner’s enriched solvent, such as by duplicating Rayner’s absorber 1 and flash desorbers 2 and repeating its absorption and flashing/desorption steps as desired, the duplication of prior art parts and steps being prima facie obvious as detailed above.
Claims 6 and 11 are rejected under 35 U.S.C. 103 as being unpatentable over Rayner in view of Park (herein collectively “R/P”), further in view of the 2008 Heldebrant et al. Energy Environ. Sci. article (“Heldebrant”). Regarding claim 6, R/P5 teaches DBU-ROH and TMG-ROH, but is silent as to the specific alcohol employed.
For its part (and thereby elaborating on Park’s adapt[ation] thereof), Heldebrant employs an alcohol such as 1-hexanol (herein “HxOH”) with its DBU or TMG, stating that employing such an alcohol results in rapid CO2 sorption (“uptake of CO2 at 28oC was complete within 20 seconds”). See Heldebrant at, e.g., pp. 488-89 (“Results and discussion” “CO2 uptake” section); Figs. 1-2. As such, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to modify R/P’s overall methodology by employing, in conjunction with its DBU or TMG, HxOH as its ROH alcohol as taught (or elaborated upon) by Heldebrant, given Heldebrant’s teaching of the appropriateness and effectiveness thereof in (rapidly) sorbing CO2. MPEP 2143 I.(E) & 2144.07.
Regarding claim 11, Heldebrant employs a 1:1 molar ratio of DBU (MW = 152.24 g/mol) or TMG (MW = 115.18 g/mol) (which Heldebrant employs interchangeably with DBU, rendering it prima facie obvious to do so: MPEP 2144.06 II, citing In re Fout) with an alcohol such as HxOH (MW = 102.18 g/mol). See Heldebrant at, e.g., pp. 488-89 (“Results and discussion” “CO2 uptake” section); Figs. 1-2. For DBU-HxOH, this equates to 254.42 g total, of which ~40 wt% is HxOH and ~60 wt% is DBU. For TMG-HxOH, this equates to 189.30 g total, of which ~39 wt% is HxOH and ~61 wt% is TMG. When employing Heldebrant’s DBU-HxOH or TMG-HxOH along with R/P’s sulfolane, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to ascertain and employ an amount/concentration of sulfolane, such as that sufficient to employ DBU/TMG, HxOH, and sulfolane within the claimed concentration ranges, via routine experimentation, based upon such factors as achieving/maintaining a desirable viscosity for the overall mixture- it has been held that “where the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.” See MPEP 2144.05, citing In re Aller, 220 F.2d 454, 456 (CCPA 1955); MPEP 2143 I.(G).
Conclusion
Applicant's amendment necessitated the/any new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a). A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from Examiner should be directed to DANIEL BERNS whose telephone number is (469)295-9161. Examiner can normally be reached M-F 8:30-5:00 (Central). Examiner interviews are available via telephone, in-person, and video conferencing using a USPTO supplied web-based collaboration tool. To schedule an interview, applicant is encouraged to use the USPTO Automated Interview Request (AIR) at http://www.uspto.gov/interviewpractice. If attempts to reach Examiner by telephone are unsuccessful, Examiner’s supervisor, Anthony Zimmer can be reached at (571) 270-3591. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300. Information regarding the status of published or unpublished applications may be obtained from Patent Center. Unpublished application information in Patent Center is available to registered users. To file and manage patent submissions in Patent Center, visit: https://patentcenter.uspto.gov. Visit https://www.uspto.gov/patents/apply/patent-center for more information about Patent Center and https://www.uspto.gov/patents/docx for information about filing in DOCX format. For additional questions, contact the Electronic Business Center (EBC) at 866-217-9197 (toll-free). If you would like assistance from a USPTO Customer Service Representative, call 800-786-9199 (IN USA OR CANADA) or 571-272-1000.
/DANIEL BERNS/ February 16, 2026
Primary Examiner
Art Unit 1736
1 It is noted that ‘604 was also not previously made of record.
2 As sulfolane’s viscosity and BP values are within the claimed ranges, and sulfolane is specifically listed in claim 10’s physical solvent list, Examiner regards sulfolane as inherently and/or implicitly meeting claim 9’s dielectric constant property as well. See In re Best, 562 F.2d 1252, 1255 (CCPA 1977); MPEP 2112.01 & 2144.01. This conclusion is buttressed by the Federal Circuit’s holding that “[w]hen a chemical composition is claimed, a prima facie case of obviousness under Section 103 may be established by [the prior art’s teaching of] a
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similar composition, the presumption being that similar compositions have similar properties.” See, e.g., In re Soni, 34 USPQ2d 1684, 1687 (Fed. Cir. 1995) (internal citations omitted); Titanium Metals Corp. v. Banner, 778 F.2d 775 (Fed. Cir. 1985); MPEP 2112.01 I-II; MPEP 2144.09 I, citing In re Payne, 606 F.2d 303, 313 (CCPA 1979).
3 See In re Harza, 274 F.2d 669, 124 USPQ 378 (CCPA 1960); Petroleo Brasileiro S.A.-- Petrobras v. Comm’r of Patents and Trademarks, 2 USPQ2d 1720, 1721-22 (D.D.C. 1987) (affirming BPAI conclusion that using multiple reactors would have been obvious to one of skill in the art where the prior art teaches only a single, similar reactor); MPEP 2144.04 VI.B.-C.
4 See also fn. 2, above.
5 It is noted that Park states that its teachings of DBU-ROH and TMG-ROH are “adapted from [Heldebrant.]” See Park at, e.g., Scheme 3.