Prosecution Insights
Last updated: April 19, 2026
Application No. 18/283,248

CATALYSTS AND METHODS FOR THE HYDRATION AND ABSORPTION OF CARBON DIOXIDE

Non-Final OA §102§103§112
Filed
Sep 21, 2023
Examiner
MCCAIG, BRIAN A
Art Unit
1772
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Air Company Holdings, Inc.
OA Round
1 (Non-Final)
80%
Grant Probability
Favorable
1-2
OA Rounds
2y 6m
To Grant
94%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
1057 granted / 1321 resolved
+15.0% vs TC avg
Moderate +14% lift
Without
With
+13.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
30 currently pending
Career history
1351
Total Applications
across all art units

Statute-Specific Performance

§101
0.8%
-39.2% vs TC avg
§103
42.9%
+2.9% vs TC avg
§102
17.1%
-22.9% vs TC avg
§112
31.3%
-8.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1321 resolved cases

Office Action

§102 §103 §112
DETAILED ACTION Notice of Pre-AIA or AIA Status This Office action is based on the 18/283,248 application filed 21 September 2023, which is being examined under the first inventor to file provisions of the AIA. Claims 1-12, 16, 23, 25-26, 28, 30, 33, and 36 are pending and have been fully considered. 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 appl icant regards as his invention. Claims 3 , 5 -6 , 8 -9 , and 23 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. Claim 3 recites “ further comprising a cation, the complex having the formula: [{(L 1 ) n Zn (L 2 ) m } w ] z [A y ] x , wherein: z is the charge of the {(L 1 ) n Zn (L 2 ) m } fragment, and is selected from 0 , -1, -2, or -3; A is a cation; x is the charge of the A cation, and is selected from+ 1 or +2; w is an integer equal to (y • x)/z; and y is an integer equal to (w • z)/x .” First, note that when z = 0, then w is a quotient with a divisor of zero, which, by definition is undefined and, consequently, indefinite. Also, note that when z = 0, y=0, which indicates that there is no cation A. Therefore, it is unclear whether claim 3 requires a cation or not. Additionally, note that w and y are defined circularly so that substitution of either one into the other yields either w = w or y = y. Consequently, the values for w and y are unknown and the metes and bounds of the claimed invention cannot be determined. Claim 5 recites “…wherein L 1 is selected from ethylenediaminetetraacetic acid (EDTA), glutaric acid, nitrilotriacetic acid,… ” However, claim 1 recites that L 1 is a…ligand . Ligands are chemical groups bound to a central atom by a coordinate bond. None of the compounds recited in instant claim 5 are ligands; rather, they are chemical compounds not bound to a central atom by a coordinate bond. Perhaps claim 5 should be amended to recite “…wherein L 1 is selected derived from ethylenediaminetetraacetic acid (EDTA), glutaric acid, nitrilotriacetic acid,… ” With respect to claim 6, said claim recites “ c is, independently at each occurrence, an integer from 0 -3…” When c is 0, then a ligand having a formula L 1B does not exist. Consequently, it is not clear if the ligand L 1 actually comprises L 1B or not. The claim appears to contain a contradiction. With respect to claim s 9 and 23 , said claim recites “…is stable at a pH from about 7 to about 16 .” The conventional range of pH is 0-14. It is not clear that a pH of 16 is possible. Claim Rejections - 35 USC § 102 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 the appropriate paragraphs of 35 U.S.C. 102 that form the basis for the rejections under this section made in this Office action: A person shall be entitled to a patent unless – (a)(1) the claimed invention was patented, described in a printed publication, or in public use, on sale , or otherwise available to the public before the effective filing date of the claimed invention. Claim(s) 1 and 3- 6 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Steinke et al (US 2011/0218320). With respect to claims 1 and 4 -5 , Steinke et al discloses “ [a] 1 l[ iter ] four-necked flask provided with stirrer bar, heating bath and water separator was initially charged with 35 g of triturated zinc oxide in 250 ml of absolute toluene . After addition of 53 g of glutaric acid , the mixture was heated to 55 o C. while stirring for 2 hours. Thereafter, it was heated to boiling, in the course of which the water of reaction was distilled off by azeotropic means under reflux, until no further water was distilled over. The toluene was distilled off, and the residue was dried at 80 o C. under high vacuum ” [paragraph 0093], which residue is zinc glutarate [see paragraph 0095: “ 12 g of zinc glutarate from example 1 were …”]. Compare the preceding to the method of the instant application [see paragraphs 0133-0134 of the published application: “ [z] inc oxide (1 equiv.) and ligand (1 equiv.) are stirred in a solvent …, optionally with heating, until complex formation is complete . The solution is optionally concentrated, and cooled to induce precipitation. A co-solvent may be added to induce precipitation. The zinc complex is collected by vacuum filtration , optionally washed, and dried under reduced pressure , with optional heating , to obtain the final product. Example 2: Synthesis of zinc glutarate ( ZnGA ) Glutaric acid (129 g, 0.98 mol) was slowly added to 1.5 L of toluene , which was heated to 60 ° C. while vigorously stirring for 1.0 hour to partially dissolve the glutaric acid. Zinc oxide (81.3 g, 1.0 mol) was added to the suspension and the mixture was stirred at 60 ° C. for an additional 4.0 hours. The light blue-purple suspension was cooled down to room temperature and filtered using a vacuum filtration system, and washed with acetone three times, resulting in a light purple powder. The powder was further dried in a vacuum oven at 60 ° C ., 20 mmHg for 24 hours, resulting in 175 g of a fluffy purple ZnGA power ”]. Note the same zinc oxide precursors, same solvents (toluene), same ligands ( glutarate ), same vacuum filtration, same drying under reduced pressure with heating in both Steinke et al and the instant application. The zinc glutarate of the reference corresponds to the formula in instant claim 1 when m is 0 and n is 1 . Glutarate corresponds to a bidentate and di-anionic L 1 ligand that is bound to zinc via oxygen atoms . With respect to claim s 3, zinc glutarate corresponds to the recited formula where z is 0 and, thus, y is 0. With respect to claim 6, note that glutarate corresponds to L 1B , wherein R 4 is H and c is 3. Claim(s) 1 , 3, and 5 -7 is/are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Bang et al ( KR 1020180060647 ) Note: in the discussion that follows, reference will be made to the WIPO machine translation of the aforementioned reference. Bang et al discloses a “ zinc dicarboxylate-based compound [that] is a reaction product of a zinc precursor and a dicarboxylic acid having 3 to 20 carbon atoms ,… the zinc precursor may be at least one compound selected from the group consisting of zinc oxide ( ZnO ), zinc sulfate (ZnSO 4 ), zinc chlorate (Zn(ClO 3 ) 2 ), zinc nitrate (Zn(NO 3 ) 2 ), zinc acetate (Zn(OAC) 2 ), and zinc hydroxide (Zn(OH) 2 ). In addition, the dicarboxylic acid having 3 to 20 carbon atoms may be at least one compound selected from the group consisting of malonic acid, glutaric acid,… ” [see page 3 of translation]. Zinc malonate, one of the aforementioned zinc dicarboxylate-based compound s corresponds to the zinc complex of instant claims 1, 3, and 6-7 where m is 0, n is 1, z is 0, R 4 is H, and c is 1. 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, 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. Claim(s) 2 and 8 - 10 is/are rejected under 35 U.S.C. 103 as being unpatentable over Steinke et al (US 2011/0218320) or Bang et al ( KR 1020180060647 ) . With respect to claims 2 and 9 -10 , since the zinc glutarate of Steinke et al and/or Bang et al is the same as the zinc complex of the instant application, it is expected, absent evidence to the contrary that the glutarate is stable under basic conditions including a pH from about 7 to about 1 4 or about 8 to about 10 . With respect to claim 8, when z is 0, y is 0 and, thus, the cation, A, may be any cation including, obviously, the alkali and alkaline earth metals recited in the instant claim. Claim(s) 1, 3-4, 11- 12, 16, 23, 33, and 36 is/are rejected under 35 U.S.C. 103 as being unpatentable over Davis et al (US 2005/0109210) alone or, alternatively, in view of Valdez et al (US 2012/0199535). With respect to claims 1 , 3-4, 11, and 33 , Davis et al discloses a method “to remove hydrogen sulphide from gases and liquids, and methods for its use….Additionally, the solution and methods of this invention can be used to remove carbon dioxide from gases and liquids, particularly in cold temperatures. Accordingly, in one aspect the invention is a solution for removing a sulphur compound or carbon dioxide from a gas or a liquid, said solution comprising: (a) sulphuric acid , at between about 0.1 to 10 percent by volume of the solution; (b) a metal , at between about 0.05 to 10 percent by weight of the solution; (c) an amine at between about 10 to 80 percent by volume of the solution; and (d) water” [paragraphs 0007-0012], wherein “ the sulphuric acid is in the form of a chelating agent ” [paragraph 0013] and “ the sulphuric acid is in the form of a chelating agent … ‘C helating agent ’ as used herein refers to a molecule that can chelate metal ions ” [paragraph 0058] and “ the metal is copper, zinc , or a mixture of copper and zinc ” [paragraph 0028] and “[t] he zinc solution may be derived from mixing solid zinc sulphate monohydrate with water or another liquid ” [paragraph 0063] . The reference further teaches “FIG. 1A shows one embodiment of the method of this invention in which a gas comprising one or more compounds that are to be removed from the gas is bubbled through a solution of the invention . Examples of the compounds that are to be removed from the gas include… carbon dioxide . As seen in FIG. 1, solution 10 is placed into a container 12 that has an entrance opening 14 and an exit opening 16. Entrance opening is fitted with a device 15, such as a one-way valve, that will prevent solution 10 from running out of container 12. The gas 18 enters container 12 through entrance opening 14 and passes through solution 10 by rising upwards because of its low density. Gas 18 exits container 12 through exit opening 16. As is apparent, the gas 18 moves through solution 10 as a series of bubbles, which increases the surface area of the interaction between solution 10 and gas 18, and causes turbulence in solution 10, both of which increase the efficiency of removal of the desired compounds from gas 18 ” [paragraphs 0097 and 0098]. It is obvious to one of ordinary skill in the art that the combination of (a) and (b) above results in the formation of, say, zinc sul ph ate, which is exemplified by the discussion of the same in paragraph 0063. The aforementioned zinc sulphate corresponds to the zinc complex of instant claim 11, where sulfate is the at least one ligand coordinated to zinc. Zinc sulfate also corresponds to the zinc complex of the formula of instant claim s 1 , 3-4, 16, and 36 where m is 0; n is 1; z is 0; L 1 is the aforementioned sulfate, which is bidentate and di-anionic and is bound to zinc through oxygen. The container 12 corresponds to the apparatus of instant claim 33. Alternatively, Valdez et al, which is concerned with “[a] system … that substantially increases the efficiency of CO 2 capture and removal …” [abstract] , discloses “ FIG. 5 illustrates some examples of zinc-containing aza -macrocyclic ligands demonstrated to catalyze the carbon dioxide hydration reaction … The metal ion 501 depicted in these examples is zinc (II) ” [paragraph 0064], wherein the carbon dioxide hydration reaction “ yield [s] water-soluble bicarbonate ” [paragraph 0058]. center 0 0 0 In one embodiment, the zinc-containing aza -macrocyclic ligand may be C 10-18 -N-Cyclen Zinc [paragraph 0041 & Figure 6] , wherein the cyclen is a di -anionic, tetra dentate ligand corresponding to L 1 in the instant claim s 1 and 16 . The catalyst comprising the zinc-containing aza -macrocyclic ligand corresponds to the formulas in claims 1 , 3, 16, and 36 when m is 0 or 1 , n is 1 , and z is 0 . At the time of the effective filing date of the instant application, it would have been obvious to one of ordinary skill in the art to modify the teaching of the metal and chelating agent of Davis et al with the zinc ligand of Valdez et al because 1) " [i] t is prima facie obvious to combine two compositions each of which is taught by the prior art to be useful for the same purpose, in order to form a third composition to be used for the very same purpose....[T]he idea of combining them flows logically from their having been individually taught in the prior art." In re Kerkhoven , 626 F.2d 846, 850, 205 USPQ 1069, 1072 ; and 2) the system of Valdez et al “… substantially increases the efficiency of CO 2 capture and removal over current state of the art methods by positioning the catalyst within an optimal distance from the air-liquid interface ” [paragraph 0031]. Therefore, the invention as a whole would have been prima facie obvious. With respect to claim 12, it is well known that zinc sulfate is very soluble in water (e.g., 57.7 g/100 mL H 2 O at 20 o C). Therefore, it is expected that the zinc solution of Valdez et al is homogeneous. With respect to claim 23, Davis et al discloses “[t] he pH of the resultant solution will generally be between 8 and 12 , but can be adjusted to almost any pH. The inventors have determined that the solution is very efficient at removing hydrogen sulphide when the pH is adjusted to be above 8 and most efficient in the 10 to 11 range ” [paragraph 0093]. Allowable Subject Matter Claims 25-26, 28, and 30 are objected to as being dependent upon a rejected base claim, but would be allowable if rewritten in independent form including all of the limitations of the base claim and any intervening claims. The following is a statement of reasons for the indication of allowable subject matter: With respect to claim 25, note than both Davis et al and Valdez et al disclose a method conducted under basic pH (i.e., 7-14) . Valdez further teaches “[a] s illustrated in the above reactions (Equations 1 and 2), in water with an approximately neutral pH value, the catalyst will increase the conversion of CO 2 into carbonic acid (H 2 CO 3 ). In a basic solution , the catalyst will increase the reaction rate of converting CO 2 into bicarbonate (HCO 3 - ). This formation of HCO 3 - in a basic solution occurs in an irreversible fashion, eliminating the possibility of regenerating any CO 2 gas ” [paragraph 0059]. Consequently, it does not appear that releasing gaseous carbon dioxide is possible with the process(es) of Davis et al and/or Valdez et al. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to FILLIN "Examiner name" \* MERGEFORMAT BRIAN A MCCAIG whose telephone number is FILLIN "Phone number" \* MERGEFORMAT (571)270-5548 . The examiner can normally be reached FILLIN "Work Schedule?" \* MERGEFORMAT Monday to Friday 8 to 4:30 Mountain Time . 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, FILLIN "SPE Name?" \* MERGEFORMAT In Suk Bullock can be reached at FILLIN "SPE Phone?" \* MERGEFORMAT 571-272-5954 . 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. /BRIAN A MCCAIG/ Primary Examiner, Art Unit 1772 5 March 2026
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Prosecution Timeline

Sep 21, 2023
Application Filed
Mar 05, 2026
Non-Final Rejection — §102, §103, §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

1-2
Expected OA Rounds
80%
Grant Probability
94%
With Interview (+13.6%)
2y 6m
Median Time to Grant
Low
PTA Risk
Based on 1321 resolved cases by this examiner. Grant probability derived from career allow rate.

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