Prosecution Insights
Last updated: April 19, 2026
Application No. 18/577,434

ADSORPTION METHOD FOR NITRILOTRIACETIC ACID (NTA) REMOVAL FROM EDTA CONTAINING CHELANT SOLUTIONS

Non-Final OA §112
Filed
Jan 08, 2024
Examiner
PERRIN, CLARE M
Art Unit
1779
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Dow Global Technologies LLC
OA Round
1 (Non-Final)
67%
Grant Probability
Favorable
1-2
OA Rounds
2y 11m
To Grant
99%
With Interview

Examiner Intelligence

Grants 67% — above average
67%
Career Allow Rate
492 granted / 733 resolved
+2.1% vs TC avg
Strong +43% interview lift
Without
With
+42.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
44 currently pending
Career history
777
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
41.3%
+1.3% vs TC avg
§102
17.1%
-22.9% vs TC avg
§112
30.9%
-9.1% vs TC avg
Black line = Tech Center average estimate • Based on career data from 733 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 . Claim Status Claims 1-10 are pending. 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 1-10 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. With respect to claim 1, the limitations “selective removal of one or more nitrilotriacetic acid salts from an aqueous chelating agent composition” renders the claim indefinite, as it is unclear to the Examiner what the nitrilotriacetic acid salts are selectively removed with respect to. For example, “the aqueous chelating agent composition” could simply comprise the one or more nitrilotriacetic acid salts. Due to this confusion, the limitations “while retaining 95 wt.% or more of the chelating agent in the aqueous chelating agent compositions” is further unclear, as the one or more nitrilotriacetic acid salt(s) themselves are chelating agents. For the purposes of examination, the Examiner will consider the limitations to be met by a teaching of removing one or more nitriloacetic acid salt(s) with one or more adsorbents from an aqueous composition comprising the one or more nitriloacetic acid salt(s). Applicant may wish to consider amending claim 1 to recite which other chelating agents are present in the aqueous chelating agent composition in order to overcome this rejection (as was done in the 28 October 2024 claim set of corresponding European application # EP 22787073). Regarding claims 2-10, they are rejected for being dependent on a rejected base claim. Allowable Subject Matter Claims 1-10 are allowed, pending resolution of the 112(b) rejections set forth above, as none of the prior art teaches or suggests the method for selectively removing one or more nitriloacetic acid salt(s) as recited in claim 1. The Examiner would like to acknowledge the following references which are relevant to the claimed invention, but which fall short of disclosing the same: 1) Krishnan et al. (Colloids and Surfaces A, 2008, 317, 344-351, cited on the ISR), in which is disclosed a method for removing nitriloacetic acid from an aqueous composition (Abstract), comprising treating the aqueous composition with an activated carbon adsorbent derived from sawdust of rubber wood (see Abstract; Sections 2.1, 2.4), wherein the aqueous chelating agent composition comprises 0.25 and 0.50 mmol/M nitrilotriacetic acid (NTA), equivalent to 0.25 moles/L and 0.50 moles/L, or 0.25 ppm and 0.50 ppm, which is equivalent to 0.000025% and 0.00005% of the aqueous composition. Even with the Examiner’s interpretation of “the aqueous chelating agent composition” set forth in the 112(b) rejection of claim 1 above, the content of the one or more nitrilotriacetic acid salt(s) in the aqueous composition of Krishnan is several orders of magnitude lower than the lower bound of “1 to 60 wt.%, based on the total weight of the aqueous composition, of one or more chelating agents”. Krishnan also does not teach “retaining 95 wt.% or more of the chelating agents in the aqueous chelating agent compositions, as NTA is adsorbed from the aqueous composition of Krishnan and is the only chelating agent present. 2) Shan et al. (Journal of Hazardous Materials, 2015, 299, 479-485), in which is disclosed adsorption of free and nitrilotriacetic acid complexed Cd(II) on poly(1-vinylimidazole)-grafted Fe3O4@SiO2 magnetic nanoparticles (“one or more adsorbents”) (see Abstract; Sections 2.1-2.3), wherein nitrilotriacetic acid complexed Cd(II) is present in solution at 50 µg/L (see Abstract; Section 2.3), or 0.050 ppm (0.000005%). Like Krishnan, the only “chelating agent” present is NTA with complexed Cd(II); therefore, Shan also does not teach “retaining 95 wt.% or more of the chelating agents in the aqueous chelating agent compositions, as NTA is adsorbed from the aqueous composition of Shan and is the only chelating agent present. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to CLARE M PERRIN whose telephone number is (571)270-5952. The examiner can normally be reached 9AM-6PM EST M-F. 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, Bob Ramdhanie can be reached at (571) 270-3240. 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. /CLARE M. PERRIN/ Primary Examiner Art Unit 1779 /CLARE M PERRIN/Primary Examiner, Art Unit 1779 03 March 2026
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Prosecution Timeline

Jan 08, 2024
Application Filed
Mar 03, 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

1-2
Expected OA Rounds
67%
Grant Probability
99%
With Interview (+42.9%)
2y 11m
Median Time to Grant
Low
PTA Risk
Based on 733 resolved cases by this examiner. Grant probability derived from career allow rate.

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