Prosecution Insights
Last updated: April 19, 2026
Application No. 18/561,836

DISTILLATION PROCESS WITH A LAVAL NOZZLE

Final Rejection §103§112
Filed
Nov 17, 2023
Examiner
ROBINSON, RENEE E
Art Unit
1772
Tech Center
1700 — Chemical & Materials Engineering
Assignee
BASF Corporation
OA Round
2 (Final)
74%
Grant Probability
Favorable
3-4
OA Rounds
2y 11m
To Grant
97%
With Interview

Examiner Intelligence

Grants 74% — above average
74%
Career Allow Rate
759 granted / 1029 resolved
+8.8% vs TC avg
Strong +24% interview lift
Without
With
+23.5%
Interview Lift
resolved cases with interview
Typical timeline
2y 11m
Avg Prosecution
35 currently pending
Career history
1064
Total Applications
across all art units

Statute-Specific Performance

§101
0.4%
-39.6% vs TC avg
§103
43.3%
+3.3% vs TC avg
§102
14.9%
-25.1% vs TC avg
§112
29.2%
-10.8% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1029 resolved cases

Office Action

§103 §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 . Response to Amendment Amendments to the abstract and to claim 11 are noted. The amendment overcomes the objection to the abstract and some, but not all, of the claim rejections under 35 USC 112(b). Response to Arguments Applicant's arguments filed 29 August 2025 have been fully considered but they are not persuasive. Applicant argues that de Faria neither discloses the claimed pump nor provides any rational basis to add one, but rather teaches away from such modification based on the process being designed to avoid additional energy-consuming equipment. This argument is not found persuasive. Applicant’s argument is conclusory and provides no additional supporting rationale that the inclusion of a pump in de Faria’s recycle line would add such sufficient additional cost as to be counter to the processing objectives. The office maintains the position that inclusion of a pump on the recycle line is an obvious modification to the process of de Faria by a person of ordinary skill in the art in determining optimum flow of the fluid in the recycle loop to the distillation column. As noted in the previous office action, this is the only difference between the claimed invention and the cited prior art. Given that pumps are well-known pieces of equipment used for the purpose of providing the driving force to transport a liquid from one operation to the next, the office maintains the position that implementing a pump in the recycle loop of de Faria would be obvious to and require nothing more than routine experimentation for a person of ordinary skill in the art. The presence of a pump in the recycle loop as claimed is not considered to provide a patentably distinguishing feature over the cited prior art. Applicant further argues that the office’s assertion that pumps are well-known is insufficient and requests evidence to support the statement. The office notes that Applicant has not specifically pointed out the supposed errors in the examiner’s action, e.g., stating why the noticed fact is not considered to be common knowledge or well-known in the art. A mere request by the Applicant that the examiner provide documentary evidence is not a proper traversal. However, as a curtesy to Applicant and for the sake of compact prosecution, the office is providing evidence which supports the noticed fact. Refer to Perry’s Chemical Engineers’ Handbook: p. 10-24 – 10-28, describing pumps (in particular, on p. 10-24: “A pump or compressor is a physical contrivance that is used to deliver fluids from one location to another through conduits”). 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. Claim 11 is 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 11 states “where at least a part of the condensation stream is condensed” (emphasis added). Given that recitation of “at least a part” includes all of the condensation stream, it is unclear how the process proceeds if all of the condensed stream is condensed in the condenser, i.e., such embodiment would entail no material being passed to the de Laval nozzle. Claim Rejections - 35 USC § 103 The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action. Claims 8-11 and 14 are rejected under 35 U.S.C. 103 as being unpatentable over de Faria et al (“Novel ethylene oxide production with improved sustainability: Loss prevention via supersonic separator and carbon capture”). Regarding claim 8, de Faria discloses a process for at least partially separating a light boiling component from a mixture containing the light boiling component and a heavy boiling component comprising (see 1.1; Fig. 2): a) feeding the mixture into a distillation column T-101 and withdrawing a distillate stream enriched in the light boiling component from the top section of the distillation column and withdrawing a bottom stream enriched in the heavy boiling component from the bottom section of the distillation column; b) transferring at least part of the distillate stream as a condensation stream to a condensation device (V-103, E-116, SS) wherein the condensation stream is at least partially condensed and recycled to the top section of the distillation column (to feed line, which is depicted as entering in the top half of the column). The condensation device comprises a de Laval nozzle having a throat, a converging zone before the throat, and a diverging zone after the throat, the condensation stream being passed into the converging zone of the de Laval nozzle, the condensation stream being accelerated to sonic speed while passing the throat, and being expanded in the diverging zone to supersonic speed, thereby at least part of the condensation stream is condensed to form a liquid recycle stream (see 1.1). de Faria does not explicitly disclose the recycle stream being passed through a pump to the top section of the distillation column. However, insofar as pumps are well-known pieces of equipment used for the purpose of providing the driving force to transport a liquid from one operation to the next, implementing a pump in the recycle loop of de Faria would be obvious to a person of ordinary skill in the art and require nothing more than routine experimentation. The presence of a pump in the recycle loop as claimed is not considered to provide a patentably distinguishing feature over the cited prior art. Regarding claim 9, de Faria discloses wherein the condensation stream is passed through a pressure-reducing device before entering the converging zone of the de Laval nozzle (see Fig. 2; 2.3; Table 1). Regarding claim 10, de Faria discloses wherein the condensation stream leaving the de Laval nozzle is passed through a pressure-reducing device (see Fig. 2; Table 1). Regarding claim 11, de Faria discloses wherein the condensation stream is passed through a condenser (flash drum V-104) where at least part of the condensation stream is condensed to form a first liquid recycle stream before the non-condensed part of the condensation stream enters the converging zone of the de Laval nozzle (see Fig. 2; 2.3). Regarding claim 14, de Faria discloses wherein the condensation stream is swirled before being passed into the converging zone of the de Laval nozzle (see 1.1; Fig. 1(a)). Allowable Subject Matter Claims 12 and 13 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: the condensation arrangements encompassed by claims 12 and 13, where the condensation stream is split up and one portion thereof is sent to the de Laval nozzle, while the other portion is sent to either a condenser and recycled or to a second de Laval nozzle and passed through the pump and recycled, respectively, is not taught or suggested by de Faria, the closest prior art. Nor does there appear to be any teaching or suggestion in the prior art which would lead a person of ordinary skill to modify de Faria in such a way as to arrive at either or the claimed embodiments encompassed by claims 12 and 13. Conclusion THIS ACTION IS MADE FINAL. 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 RENEE ROBINSON whose telephone number is (571)270-7371. The examiner can normally be reached Monday - Thursday 8:00a-5:00p and Friday 8:00a-2:00p. 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, In Suk Bullock can be reached at (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. /Renee Robinson/Primary Examiner, Art Unit 1772
Read full office action

Prosecution Timeline

Nov 17, 2023
Application Filed
Aug 01, 2025
Non-Final Rejection — §103, §112
Aug 29, 2025
Response Filed
Oct 03, 2025
Final Rejection — §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

3-4
Expected OA Rounds
74%
Grant Probability
97%
With Interview (+23.5%)
2y 11m
Median Time to Grant
Moderate
PTA Risk
Based on 1029 resolved cases by this examiner. Grant probability derived from career allow rate.

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