Prosecution Insights
Last updated: April 19, 2026
Application No. 17/366,542

METHODS AND SYSTEMS FOR PROMOTING FORMATION OF CO2 CLATHRATE HYDRATES BY THE USE OF MAGNESIUM AND OTHER ACTIVE METALS

Non-Final OA §112
Filed
Jul 02, 2021
Examiner
TAYLOR, JORDAN W
Art Unit
1738
Tech Center
1700 — Chemical & Materials Engineering
Assignee
ExxonMobil
OA Round
5 (Non-Final)
68%
Grant Probability
Favorable
5-6
OA Rounds
2y 12m
To Grant
99%
With Interview

Examiner Intelligence

Grants 68% — above average
68%
Career Allow Rate
94 granted / 139 resolved
+2.6% vs TC avg
Strong +40% interview lift
Without
With
+40.4%
Interview Lift
resolved cases with interview
Typical timeline
2y 12m
Avg Prosecution
52 currently pending
Career history
191
Total Applications
across all art units

Statute-Specific Performance

§101
1.8%
-38.2% vs TC avg
§103
54.3%
+14.3% vs TC avg
§102
14.2%
-25.8% vs TC avg
§112
24.5%
-15.5% vs TC avg
Black line = Tech Center average estimate • Based on career data from 139 resolved cases

Office Action

§112
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 . Examiner’s Note Multiple attempts to contact the Applicant’s Attorney Joseph Snyder (#39381) were made in order to expedite prosecution with an Examiner’s amendment however not reply was received by Examiner from Applicant within 72 hours and this action was instead mailed. Continued Examination Under 37 CFR 1.114 A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/19/2025 has been entered. Response to Amendment The amendment filed on 12/19/2025 has been entered. Claims 1-3, 6, 10, 18, 25-27, 33, 35-36, and 107-114 are pending in the application. Applicant’s Amendment is supported in the instant specification in at least [0051], [0059], and [0084]-[0085]. However, Applicant’s amendment has introduced 112(b) rejections that are outlined in detail below. The affidavit under 37 CFR 1.132 filed 12/19/2025 is insufficient to overcome the rejection of claim 1 based upon the rejection of Sonoda as set forth in the last Office action because: the Declarant Dr. Vaibhav Bahadur states in par. 5-7 that the prior art Sonoda does not teach or suggest clathrate hydrate formation and that the purpose of the aluminum powder in Sonoda is for being a contrast agent and not for forming CO2 clathrate hydrates. However, this is unconvincing because the process as claimed was substantially similar to the process of Sonoda, as described in the previous rejection of 10/10/2025. It has been detailed numerous times by the Examiner Sonoda describes hydrate formation occurring under certain conditions and states, with experiments under production states showing carbon dioxide hydrate being observed ([0009] and [0026]). The declarant states in Par. 8-11 that the order of mixing in Sonoda would quickly form passivated oxide layers rendering the aluminum powder inert such that gas bubbles would not be expected to form at or near the gas-liquid interface. Declarant states “in our studies, we have seen clear evidence that aluminum oxide (solely by itself) has no influence on hydrate formation.” However, while Examiner agrees with the scientific principles behind this comment, Declarant has not provided data supporting this statement. The instant specification, to the best of Examiner’s knowledge, does not include a comparison experiment performing the method of Sonoda, or a comparable method, where the aluminum powder is added directly to water and the process is shown to be inoperable. No experimental control experiments of this sort appear to be provided in the instant specification. Examiner notes the testing of anodized aluminum (i.e. aluminum with a passivated oxide surface) in table 2 ([0086]) supports aluminum surface passivation leading to no nucleation, however this test was carried out according to the process of Example 2 ([0084]) which is in line with the currently claimed method. Accordingly, a control experiment where the order of aluminum powder is reversed (i.e. added to water prior to applying pressurizing clathrate hydrate conditions) appears to be lacking. To be of probative value, statements need to be supported by factual proof and Applicant arguments cannot takes the place of evidence. See MPEP 716.01(c). Declarant states in Pg. 13-15 the claims require sparging CO2 through the liquid while Sonoda does not teach or suggest sparging. Declarant states the sparging is functionally directed to enhancing nucleation by increasing the number of available gas-liquid interfaces. Declarant states experimental data and discussion present in the application show that the reactive metal substrate actively generates hydrogen bubbles at the interface and these bubbles promote nucleation of CO2 clathrate hydrates. However, as Examiner previously presented, Sonoda is not relied on to teach sparging CO2 through solution, but rather the prior art Mettler is. The fact that the inventor has recognized another advantage which would flow naturally from following the suggestion of the prior art cannot be the basis for patentability when the differences would otherwise be obvious. See Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985). Additionally, one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981); In re Merck & Co., 800 F.2d 1091, 231 USPQ 375 (Fed. Cir. 1986). Response to Arguments Applicant’s arguments, see Pg. 5-8, filed 12/19/2025, with respect to Claim 1 have been fully considered and are persuasive. In particular, Applicant’s arguments regarding the order of adding the metal after establishing nucleation conditions at or near a gas-liquid or liquid interface are not fairly taught in the prior art. Further, the formation of passivated surfaces on the reactive metal nucleation substrate when adding the reactive metal nucleation substrate directly to water in the absence of clathrate hydrate formation conditions is convincing. The 35 USC § 103 of 10/10/2025 has been withdrawn. Claim Rejections - 35 USC § 112 The following is a quotation of 35 U.S.C. 112(b): (b) CONCLUSION.—The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the inventor or a joint inventor regards as the invention. The following is a quotation of 35 U.S.C. 112 (pre-AIA ), second paragraph: The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention. Claims 1-3, 6, 10, 18, 25-27, 33, 35-36, 107-114 are rejected under 35 U.S.C. 112(b) or 35 U.S.C. 112 (pre-AIA ), second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which the inventor or a joint inventor (or for applications subject to pre-AIA 35 U.S.C. 112, the applicant), regards as the invention. Regarding claim 1, line 5 recites the limitation "the gas-liquid interface" however there is insufficient antecedent basis for this limitation in the claim. While gaseous CO2 and a liquid comprising water are previously introduced in the claim, these do not necessarily generate a “gas-liquid interface” such that the limitation is provided sufficient basis. Regarding claim 1, line 6, the phrase “substantially simultaneously” is a relative term which renders the claim indefinite. The term “substantially” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. To the best of Examiner’s knowledge, the instant specification does not include the word “substantially” and accordingly a skilled artisan viewing the limitation would not know the metes and bounds of the limitation, nor how to add a reactive metal nucleation substrate at or near a gas-liquid interface such that the addition is “substantially simultaneously”. The term “simultaneously” is supported in the instant specification, with sufficient description in at least [0059]. Regarding claim 110, line 6, the phrase “substantially simultaneously” is a relative term which renders the claim indefinite. The term “substantially” is not defined by the claim, the specification does not provide a standard for ascertaining the requisite degree, and one of ordinary skill in the art would not be reasonably apprised of the scope of the invention. To the best of Examiner’s knowledge, the instant specification does not include the word “substantially” and accordingly a skilled artisan viewing the limitation would not know the metes and bounds of the limitation, nor how to add a reactive metal nucleation substrate at or near . The term “simultaneously” is supported in the instant specification, with sufficient description in at least [0059]. Claims 2-3, 6, 10, 18, 25-27, 33, 35-36, 107-109, and 111-112 all depend from claim 1 and thus, are also rendered indefinite. Claims 113-114 all depend from claim 110 and thus, are also rendered indefinite. Allowable Subject Matter Claims 1-3, 6, 10, 18, 25-27, 33, 35-36, 107-114 are allowed pending the Examiner’s Amendment above. REASONS FOR ALLOWANCE The following is an examiner’s statement of reasons for allowance:. The closest prior art reading on the instant invention identified by the Examiner during search is Sonoda et al. (JP3609047B2; English Descr.). Sonoda teaches a method of generating carbon dioxide clathrate hydrates (0008-0010) by contacting gaseous or liquid carbon dioxide (L in Figure 1) with seawater (W in Figure 1) and powdered aluminum (claimed reactive metal nucleation substrate that is a Group XIII metal) and subjecting the materials to conditions to produce carbon dioxide clathrate hydrates. See paragraphs 0022-0026. Sonoda teaches aluminum powder is mixed in one of seawater and carbon dioxide forming an interface prior to pressurizing the mixture ([0014], [0025]). While the prior art does disclose contacting liquid carbon dioxide and seawater with aluminum powder, Sonoda does not teach or suggest the aluminum powder is introduced at a gas-liquid interface after establishing clathrate hydrate nucleation condition. Sonoda exclusively teaches mixing the components prior to pressurizing and there is no teaching or suggestion in Sonoda for a skilled artisan to try otherwise. Regarding claim 110, the same logic is true for Sonoda failing to disclose adding alumina powder at a liquid interface after establishing clathrate hydrate nucleation conditions. For this reason, the process of Sonoda is not substantially similar to the instant invention and the limitation is considered to be novel and nonobvious. Other relevant prior art identified during search include the following: Mettler et al. (US20180229178A1): Mettler teaches a process for forming and sequestering CO2 clathrates that includes providing a CO2-rich stream to an aqueous solution under temperature and pressure conditions suitable to form hydrates (Abstract; [0006]-[0007]; [0043]). Mettler further teaches that the gas feed inlet for introducing CO2 bubbles into the reactor is done with a sparger or an arrangement of a plurality of small nozzles ([0045]-[0047]). Mettler further teaches control of the gas feed, including of its temperature and pressure, is considered well-known in the art ([0047]). While this reference discloses sparging CO2 through a system that provides CO2 clathrates, it does not teach nor suggest that a reactive metal nucleation substrate is added at a gas-liquid or liquid interface after establishing hydrate nucleation conditions. For these reasons, Mettler et al. does not remedy the deficiencies of Sonoda et al. Li et al. (J. Coll. Int. Sci. 2005, 283, 223-230): Li teaches a method of submerging iron rods into water solutions prior to reducing the temperature to initiate hydrate growth (Title; Pg. 225, 3.1-3.2; Fig. 2-3). While this reference discloses submerging metal rods at a liquid interface, it does not teach nor suggest that liquid contains CO2 to form a gas-liquid interface, nor does it teach or suggest the metal rod is submerged after establishing nucleation conditions. For these reasons, Li et al. does not remedy the deficiencies of Sonoda et al. Tabe et al. (J. Cryst. Growth 2000, 220, 180-184): Tabe teaches a process for initiating massive CO2 clathrate growth at a high-polar-energy surface, where Tabe teaches a polar surface, including glass, copper, and stainless-steel, are submerged at a liquid CO2 interface to initiate clathrate formation (Title; Fig. 1; Pg. 181, 2. Experimental Procedure; Pg. 183, left and right col.). While this reference discloses forming CO2 clathrates at a liquid CO2-polar-energy surface area material, it does not teach nor suggest that the polar-energy surface area material is added after establishing clathrate hydrate nucleation conditions, teaching exclusively that the experimental setup was pressurized after contacting the polar-energy surface area material with the liquid CO2 (Pg. 181, left col.). For these reasons, Tabe et al. does not remedy the deficiencies of Sonoda et al. Spencer (US6235091); Spencer teaches a process for generating CO2 clathrates and selectively separating them from a multi-component gaseous stream, where nucleated water that has been pressurized is fed to a reactor containing metal oxides to promote formation of CO2 clathrates or hydrates (Title; Col. 4, lines, 22-53; col. 6, lines 5-16). While this reference discloses feeding pressurized nucleated water containing CO2 to a reactor containing a metal oxide, it does not teach or suggest the metal is an element or an alloy, exclusively teaching oxide forms of metals (see col. 6, lines 5-16). As the metal identity (element/alloy vs. oxide) is important to bubble formation and subsequent clathrate hydrate formation, a skilled artisan viewing the teaching of Spencer would conclude only oxides are operable and therefore have no motivation or expectation of success in substituting the metal oxide for the element/alloy as claimed in the instant invention. For these reasons, Spencer et al. does not remedy the deficiencies of Sonoda et al. Any comments considered necessary by applicant must be submitted no later than the payment of the issue fee and, to avoid processing delays, should preferably accompany the issue fee. Such submissions should be clearly labeled “Comments on Statement of Reasons for Allowance.” Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to Jordan Wayne Taylor whose telephone number is (571)272-9895. The examiner can normally be reached Monday - Friday, 7:30 AM - 5 PM EST; Second Fridays Off. 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 the examiner by telephone are unsuccessful, the examiner’s supervisor, Sally A. Merkling can be reached on (571)272-6297. 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. /J.W.T./Examiner, Art Unit 1738 /SALLY A MERKLING/SPE, Art Unit 1738
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Prosecution Timeline

Jul 02, 2021
Application Filed
Jul 01, 2024
Non-Final Rejection — §112
Oct 10, 2024
Response Filed
Oct 24, 2024
Final Rejection — §112
Feb 05, 2025
Request for Continued Examination
Feb 06, 2025
Response after Non-Final Action
Jun 02, 2025
Non-Final Rejection — §112
Aug 14, 2025
Response Filed
Oct 02, 2025
Final Rejection — §112
Dec 19, 2025
Request for Continued Examination
Dec 19, 2025
Response after Non-Final Action
Dec 23, 2025
Response after Non-Final Action
Mar 19, 2026
Non-Final Rejection — §112 (current)

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Study what changed to get past this examiner. Based on 5 most recent grants.

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Prosecution Projections

5-6
Expected OA Rounds
68%
Grant Probability
99%
With Interview (+40.4%)
2y 12m
Median Time to Grant
High
PTA Risk
Based on 139 resolved cases by this examiner. Grant probability derived from career allow rate.

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