Prosecution Insights
Last updated: April 19, 2026
Application No. 17/928,565

PROCESS FOR ACETIC ACID PRODUCTION BY REMOVING PERMANGANATE REDUCING COMPOUNDS

Final Rejection §102§103
Filed
Nov 29, 2022
Examiner
BAHTA, MEDHANIT W
Art Unit
1692
Tech Center
1600 — Biotechnology & Organic Chemistry
Assignee
Celanese International Corporation
OA Round
2 (Final)
80%
Grant Probability
Favorable
3-4
OA Rounds
2y 2m
To Grant
99%
With Interview

Examiner Intelligence

Grants 80% — above average
80%
Career Allow Rate
613 granted / 763 resolved
+20.3% vs TC avg
Strong +29% interview lift
Without
With
+28.6%
Interview Lift
resolved cases with interview
Typical timeline
2y 2m
Avg Prosecution
55 currently pending
Career history
818
Total Applications
across all art units

Statute-Specific Performance

§101
0.5%
-39.5% vs TC avg
§103
35.8%
-4.2% vs TC avg
§102
18.2%
-21.8% vs TC avg
§112
30.3%
-9.7% vs TC avg
Black line = Tech Center average estimate • Based on career data from 763 resolved cases

Office Action

§102 §103
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 . Status of the Claims The amendment filed on 12/03/2025 has been entered. Claims 1 and 10 have been amended. Claims 1-20 are currently pending, claims 13-20 are withdrawn, and claims 1-10 are under examination. Withdrawn Rejection The 112(b) rejection has been withdrawn in view of the amendment of claim 10. 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. Claims 1-3 and 5-12 are rejected under 35 U.S.C. 102(a)(1) as being anticipated by Patent application publication number US2018/0118651A1 (US’651; cited in IDS 11/29/2022). See underlined for modification. Regarding claim 1-3, US’651 teaches in Figs. 1 and 3, a process for separating acetaldehyde (PRC) from a first mixture 44, 43b comprising acetaldehyde, methyl iodide and water, the process comprising the steps of: feeding the first mixture 44, 43b to a first location of a distillation column 5, wherein the first mixture has a methanol mass composition that is less than the difference based on mass between methyl iodide and water (Example 6); distilling the first mixture into a second mixture and a lower stream 52, the second mixture being at least one stream selected from the group consisting of an overhead stream 53 and a sidedraw stream 63 being withdrawn higher than that of the first location where stream 44, 43b is fed; and withdrawing the lower stream 52 from a second location lower than the first location; wherein the first mixture is separated into the second mixture and lower stream without the supply of additional methanol; and wherein the second mixture is enriched in the at least one PRC ([0121]). The reference further exemplifies in Tables 9-13 that withdrawing the lower stream 52 from a second location lower than the first location when the lower stream 52 satisfies all the following conditions (i) to (iii) a total acetal mass composition in the lower stream 52 is not more than 0.02 wt %; (ii) a total acetal mass composition in the lower stream 52 is less than a combined mass composition of methanol and acetaldehyde in the lower stream 52; and (iii) a total acetal mass composition in the lower stream 52 is less than the methanol mass composition in the first mixture 44. Condition (i): Specifically, Tables 9-13 list specific components present in the lower stream 52, i.e. DME (dimethyl ether), AD (acetaldehyde), MeI (methyl iodide), MeOH (methanol), MA (methyl acetate), water, and AC (acetic acid). The total wt% of these components in the lower stream 52 amounts to 100 wt%, and thus acetal is not present in the lower stream 52, or is 0 wt%, reading on condition (i) not more than 0.02 wt %. Condition (ii): Tables 9-13 satisfies the condition because MeOH and AD are present in the lower stream 52 in view of the indicated wt% values, and thus the total acetal mass composition in the lower stream 52, 0 wt%, is lower than combined wt% of MeOH and AD in the lower stream 52. Condition (iii): The total mass composition in the lower stream 52 in Tables 9-13, 0 wt%, is less than the w% of MeOH in the first mixture 44. Regarding claim 5, the combined mass composition of MeOH and AD in the lower stream 52 of for condition (ii) in Tables 9-10 is 0.0446, 0.082, 0.408 and 0.984 wt%, respectively. Regarding claim 6, the MeOH mass composition for condition (iii) in the first mixture 44 of Tables 9-13 is 0.07, 0.08, 0.09, 0.99 and 0.99 wt%, respectively. Regarding claims 7-8, in Example 6 of US’651, the first mixture comprises 82.6 wt% MeI (methyl iodide), 1840 ppm (0.184 wt%) AD (acetaldehyde, PRC), 0.69 wt% water and 0.07 wt% methanol ([0235]). Regarding claim 9, US’651 discloses throughout the document distilling the first mixture using just water as an extractant. Regarding claim 10, the reference teaches the flow rate of the extractant relative to the first mixture ranging from 0.0001/100 to 100/100 ([0021]). Regarding claim 11, US’651 teaches the composition of the second mixture comprising methyl idodide, PRC and water at the amounts as instantly claimed ([0121]). Furthermore, since the reference teaches every limitation of the separation steps as instantly claimed, it is anticipated for the composition of the second mixture to be the same as instantly claimed. Regarding claim 12, US’651 teaches biphasically separating the second mixture into an aqueous phase and an organic phase ([0138]-[0140]). Response to Arguments Applicant is advised to refer to the above modified rejection to address the amended claim 1 and Applicant’s arguments. Claim Rejections - 35 USC § 103 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 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. The factual inquiries 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. Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Patent application publication number US2018/0118651A1 (US’651; cited in IDS 11/29/2022). The teachings of US’651 have been set forth above. Regarding claim 4, as indicated above, the reference teaches that in condition (i) the total acetal mass composition in the lower stream 52 is 0 wt% but fails to teach a mass composition of from 0.0001 wt% to 0.02 wt%. However, the instant specification describes the problems associated with the presence of acetal during the purification of PRCs in [0018] and [0022]: High amounts of total acetal reduce the ability to remove PRCs, resulting in ineffective processing. In one embodiment, to reduce the total acetal, the feed stream to the distillation column has a methanol mass composition that is maintained (controlled) to be less than the difference based on mass between the one or more C1-C12 alkyl iodides (in particular methyl iodide) and water in the stream. Reducing the total amount of acetal (and/or hemiacetals) may further enrich the mixture in PRC. As used herein the terms “mass composition” or “concentration” refers to the mass fraction of substance to the total mass and is generally expressed in % by mass or wt %, unless indicated otherwise. The present inventors have found that acetals formation proceeds to react one of the PRCs to form high boiling point components that tend to concentrate in (transfer to) the lower stream. The lower stream is a return stream, which refers to a stream that is returned to the process, such as returning to the reactor or an upstream distillation column or other suitable vessel. This undesirably introduces the acetal and/or hemiacetal throughout the process leading to a buildup of impurities that can deteriorate the quality of the acetic acid product. The instant specification further describes the approaches used to reduce the total acetal mass composition as described in [0019]-[0020]: In another embodiment, to reduce the total acetal the process may involve separating PRCs from the one or more C1-C12 alkyl iodides without an additional supply of methanol to the distillation column. In another embodiment, to reduce the total acetal the process may involve separating PRCs from the one or more C1-C12 alkyl iodides in the presence of acetic acid, water, methyl acetate and/or methanol. By conducting the above methods in reducing the acetal mass composition, Applicant achieved a lower stream with a total amount of acetal that satisfies at least one of conditions (i)-(iii), in which condition (i) is described in [0023] A total acetal amount in the lower stream is not more than 0.02 wt %, e.g., not more than 0.018 wt %, not more than 0.015 wt % or not more than 0.01 wt %. In one embodiment, to remove acetals formed in the column, the lower stream may have a lower amount that is not less than 0.0001 wt %, e.g., not less than 0.0005 wt % or not less than 0.001 wt %. US’651 does not explicitly recognize the problem associated with acetal in the lower stream and in the purification process of PRC overall. However, the reference describes the same methods that are described in the instant specification as approaches to reduce the acetal formation. For example, the method of US’651 involves: separating PRC from methyl iodide without an additional supply of methanol to the distillation column (see Figs. 1 and 3), separating PRC from methyl iodide in the presence of acetic acid, water, methyl acetate and methanol (see line 43 and 44). Thus, by conducting the above methods, one of ordinary skilled in art has a reasonable expectation of success in reducing the amount of acetal formation and further in achieving condition (i) a total acetal mass composition in the lower stream of 0.0001 wt % to 0.02 wt %. It would thus have been prima facie obvious to a skilled artisan before the effective filing date of the instant invention to conduct a process for separating at least one permanganate reducing compound (PRC) as claimed, wherein the total acetal mass composition for condition (i) is from 0.0001 wt % to 0.02 wt % in view of the teachings of US’651. Conclusion Claims 1-12 are rejected and no claims are allowed. Applicant's amendment necessitated the 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 the examiner should be directed to MEDHANIT W BAHTA whose telephone number is (571)270-7658. The examiner can normally be reached Monday-Friday 8am-5pm. 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, Scarlett Goon can be reached at 571-270-5241. 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. /MEDHANIT W BAHTA/Primary Examiner, Art Unit 1692
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Prosecution Timeline

Nov 29, 2022
Application Filed
Sep 04, 2025
Non-Final Rejection — §102, §103
Dec 03, 2025
Response Filed
Feb 06, 2026
Final Rejection — §102, §103 (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

3-4
Expected OA Rounds
80%
Grant Probability
99%
With Interview (+28.6%)
2y 2m
Median Time to Grant
Moderate
PTA Risk
Based on 763 resolved cases by this examiner. Grant probability derived from career allow rate.

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