Prosecution Insights
Last updated: April 19, 2026
Application No. 18/146,884

DIGLYCOLAMINE PROCESSING FOLLOWING ACID GAS REMOVAL FROM A GAS STREAM

Non-Final OA §112
Filed
Dec 27, 2022
Examiner
BERNS, DANIEL J
Art Unit
1736
Tech Center
1700 — Chemical & Materials Engineering
Assignee
Saudi Arabian Oil Company
OA Round
1 (Non-Final)
73%
Grant Probability
Favorable
1-2
OA Rounds
2y 9m
To Grant
99%
With Interview

Examiner Intelligence

Grants 73% — above average
73%
Career Allow Rate
588 granted / 808 resolved
+7.8% vs TC avg
Strong +35% interview lift
Without
With
+34.7%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
25 currently pending
Career history
833
Total Applications
across all art units

Statute-Specific Performance

§101
2.8%
-37.2% vs TC avg
§103
37.8%
-2.2% vs TC avg
§102
21.5%
-18.5% vs TC avg
§112
28.1%
-11.9% vs TC avg
Black line = Tech Center average estimate • Based on career data from 808 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 . Drawings The 12/27/22 drawings are provisionally accepted. Due to their complexity, applicant’s assistance is requested to ensure that all component labels therein are correctly identified in the specification and vice versa. 37 CFR 1.3 (courtesy required). Election/Restriction Applicant’s 8/19/25 election without traverse of Group I (claims 1-6) is acknowledged. Claims 7-19 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected Group, there being no allowable generic or linking claim. 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. The following is a quotation of 35 U.S.C. 112(d): (d) REFERENCE IN DEPENDENT FORMS.—Subject to subsection (e), a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. The following is a quotation of pre-AIA 35 U.S.C. 112, fourth paragraph: Subject to the following paragraph [i.e., the fifth paragraph of pre-AIA 35 U.S.C. 112], a claim in dependent form shall contain a reference to a claim previously set forth and then specify a further limitation of the subject matter claimed. A claim in dependent form shall be construed to incorporate by reference all the limitations of the claim to which it refers. Claims 1-6 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. A broad range or limitation together with a narrow range or limitation that falls within the broad range or limitation (in the same claim) may be considered indefinite if the resulting claim does not clearly set forth the metes and bounds of the patent protection desired. See MPEP § 2173.05(c). Here, claim 1 recites the broad recitation “introducing at least a first portion of the [bis-(2-hydroxyethoxyethyl)urea-comprising] at least partially regenerated aqueous amine solution to a reclaimer”, and the claim also recites “under thermal conditions effective to revert at least a majority of the bis-(2-hydroxyethoxyethyl)urea to diglycolamine,” which is the narrower statement of the range/limitation. (italics supplied) Claim 1 is rejected under 35 U.S.C. 112(b)/2nd par. for indefiniteness because there is a question or doubt as to whether the feature introduced by such narrower language is (a) merely exemplary of the remainder of the claim, and therefore not required, or (b) a required feature of the claims. In other words, since 1% of the at least partially regenerated aq. amine solution (“PRAAS”) qualifies as “at least a first portion” thereof, it is unreasonable to expect that processing such a small amount of the PRAAS in the reclaimer would be sufficient “to revert at least a majority of the bis-(2-hydroxyethoxyethyl)urea [contained in the at least partially regenerated aqueous amine solution] to diglycolamine” as claimed. The foregoing additionally and/or alternatively renders claim 1 rejected for indefiniteness under 35 U.S.C. 112(b)/2nd par. because the claim’s above-detailed internal inconsistency/contradiction creates confusion as to the claimed scope and how to avoid infringement thereof (MPEP 2173.02). See Trs. of Columbia Univ. v. Symantec Corp., 811 F.3d 1359, 1366-67 (Fed. Cir. 2016) (stating that an internally contradictive/inconsistent claim is indefinite and thus properly rejected as such under 35 U.S.C. 112(b)/2nd par.), and Multilayer Stretch Cling Film Holdings, Inc. v. Berry Plastics Corp., 831 F.3d 1350, 1362 (Fed. Cir. 2016) (citing Columbia v. Symantec). Applicant is hereby advised that, as independent claim 1 is rejected for deficiencies under 35 USC 112(b)/2nd par., all claims depending therefrom also contain such deficiencies and are likewise rejected (unless the deficiencies are resolved by the dependent claim’s own limitations) - cure thereof is required for any and all claims affected even if any such claim were otherwise found allowable. See, e.g., In re Jolly, 172 F.2d 566, 567 (CCPA 1949) (holding that dependent claims of indefinite claims are thusly indefinite), and Ex parte Kristensen, 10 USPQ2d 1701, 1702-04 (BPAI 1989) (same); 35 USC 112(d)/4th par. Potentially Allowable Subject Matter Claims 1-6 do not suffer from deficiencies under 35 U.S.C. 101 and are not anticipated or rendered prima facie obvious by the prior art. Regarding claim 1, the most pertinent prior art of record appears to be Critchfield et al., US 5,861,051 (1999) (“Critchfield”). Critchfield discloses a method comprising contacting a mixed gas 11 comprising CO2 and/or H2S acid gas with an aq. amine solution 12/13 comprising diglycolamine (“DGA”, aka 2-(2-aminoethoxy)ethanol) in an absorber 10 (see Critchfield at, e.g., col. 2, ln. 64-66 and col. 4, ln. 40-45; Fig. 1), absorbing at least some acid gas into the solution to give an acid-laden solution 16 (see id. at, e.g., col. 4, ln. 45-49; Fig. 1), liberating at least some absorbed acid gas 24 in desorber/regenerator 20 to give a PRAAS portion 26 (see id. at, e.g., col. 4, ln. 49-57; Fig. 1), sending a first portion 28 of PRAAS to a second regenerator 30 -which may be a flash unit or steam stripping column (the latter operating under thermal conditions)- to give further-regenerated aq. amine solution 32, which is thereafter recycled to absorber 10 via line 12 (see id. at, e.g., col. 4, ln. 62 to col. 5, ln. 3; Fig. 1); a second PRAAS portion 27 is recycled back to absorber 10 via line 12/13 without further purification (see id. at, e.g., col. 4, ln. 56-61; Fig. 1). Critchfield states that while DGA is known to degrade/convert to bis-(2-hydroxyethoxyethyl)urea (“BHEEU”) on contact with CO2 (see id. at, e.g., col. 4, ln. 14-18), and is converted back to DGA via a reclamation step of thermally-assisted hydrolysis and distillation (see id. at, e.g., col. 3, ln. 28 to col. 4, ln. 8), Critchfield discloses that its invention’s “improvement over the prior art” involves “keeping [DGA] under a certain range of concentration [such that] carbon dioxide can be removed effectively and without need for reclamation.” See id. at, e.g., col. 4, ln. 14-34. As such, Critchfield’s method does not include the claimed “introducing… to a reclaimer… to diglycolamine” step; even if Critchfield could be read to disclose such a step in its discussion of overall prior art methods, Critchfield does not appear to teach or suggest that prior art reclaimers are “heated with a steam input that is in indirect contact with the at least [PRAAS] and cooled with at least a [DGA] stream that is introduced directly into the at least [PRAAS] in the reclaimer” as claim 1 requires. Further, modifying Critchfield to include such a step (esp. being heated and cooled as claimed) would materially alter Critchfield’s principle of operation (which purposely omits such a step) and proceed contrary to Critchfield’s prior art wisdom; this connotes non-obviousness. MPEP 2143.01 VI & 2145 X.D.3. Conclusion 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/ November 21, 2025 Primary Examiner Art Unit 1736
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Prosecution Timeline

Dec 27, 2022
Application Filed
Nov 21, 2025
Non-Final Rejection — §112 (current)

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Prosecution Projections

1-2
Expected OA Rounds
73%
Grant Probability
99%
With Interview (+34.7%)
2y 9m
Median Time to Grant
Low
PTA Risk
Based on 808 resolved cases by this examiner. Grant probability derived from career allow rate.

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