Prosecution Insights
Last updated: April 19, 2026
Application No. 18/269,133

METHOD FOR OLIGOMERISATION IN A GAS/LIQUID REACTOR COMPRISING A CENTRAL DUCT

Non-Final OA §103
Filed
Jun 22, 2023
Examiner
NGUYEN, TAM M
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
IFP Energies Nouvelles
OA Round
3 (Non-Final)
78%
Grant Probability
Favorable
3-4
OA Rounds
2y 9m
To Grant
88%
With Interview

Examiner Intelligence

Grants 78% — above average
78%
Career Allow Rate
746 granted / 963 resolved
+12.5% vs TC avg
Moderate +11% lift
Without
With
+10.9%
Interview Lift
resolved cases with interview
Typical timeline
2y 9m
Avg Prosecution
68 currently pending
Career history
1031
Total Applications
across all art units

Statute-Specific Performance

§101
0.1%
-39.9% vs TC avg
§103
51.2%
+11.2% vs TC avg
§102
16.7%
-23.3% vs TC avg
§112
18.7%
-21.3% vs TC avg
Black line = Tech Center average estimate • Based on career data from 963 resolved cases

Office Action

§103
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 . Specification The disclosure is objected to because of the following informalities: in paragraph [0102] of the present specification described feature 15, but there is no feature 15 in any of the figures. Appropriate correction is required. 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. Claims 1-3, 5, 6, 9-10, 13-15, 19, and 20 are rejected under 35 U.S.C. 103 as being unpatentable over Xie et al. (US 5,817,902) in view of either Brown et al. (US 2005/0049447 A1) or Eugene (EP 0254277). Xie discloses a process for oligomerization of a gaseous olefin feedstock (ethylene) in a gas/liquid reactor (Fig. 1; col. 2, line 23 – col. 3, line 4; col. 4, line 6 – col. 5, line 53), comprising a vertically elongated reactor chamber, a gas injection device, a liquid injection device, and a central gas/liquid guide tube positioned along the vertical axis. The guide tube is immersed in the liquid phase (Fig. 1) and defines a central descending flow zone and an outer ascending flow zone. Gas and liquid are introduced at the upper portion of the guide tube such that the injected gas is entrained downward through the central zone and upward through the annular outer zone. Xie discloses reaction temperatures of about 100–140°C and pressures of about 2–10 MPa, overlapping the claimed ranges. Xie does not disclose a catalytic system comprising a metal precursor based on nickel, titanium, or chromium as required by claim 1. Brown discloses a process for oligomerization of ethylene using a catalyst comprising a simple divalent nickel salt (¶[0005], ¶[0007], ¶[0009]–[0010]) and teaches reaction temperatures of about 0–200°C (¶[0028]), overlapping the claimed range. The Eugene a catalyst having a metal precursor as claimed. See abstract. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Xie by employing a nickel-based oligomerization catalyst as taught by Brown because Brown/Eugene teaches such nickel catalysts are effective for ethylene oligomerization under overlapping temperature and pressure conditions. Substituting one known olefin oligomerization catalyst for another known catalyst represents a predictable substitution yielding expected results. Claims 2–3 are met by Xie’s disclosure of the positioning of gas and liquid injection devices in the upper portion of the guide tube to entrain gas downward. Claim 5, directed to flaring or tapering at the lower end of the central pipe, represents a conventional hydrodynamic optimization of draft tube geometry to improve flow transition and circulation and would have been an obvious design modification. Claim 6 is met by Xie’s disclosure of block-off plate 37 positioned beneath the guide tube outlet (col. 5, lines 28–31), which redirects flow. Claims 9–10 are directed to recirculation and heat exchange features. External heat exchange and recirculation of liquid phases are conventional in liquid-phase oligomerization systems and would have been obvious to incorporate to control reaction temperature. Claims 13–14, directed to injection orifice configuration for bubble size reduction, represent routine mixing optimization to enhance gas-liquid mass transfer. Claims 15, 19, and 20, directed to C2–C6, C2–C4, and specific olefin feedstocks, are obvious because ethylene, propylene, and butenes are conventional gaseous olefinic feedstocks for oligomerization processes. Claims 4, 7–8, 11–12, and 16–18 are rejected under 35 U.S.C. §103 as being unpatentable over Xie in view of Brown, and further in view of Hochman (US 3,737,288) and/or Zheng et al. (US 2018/0119083 A1). Xie, as modified by Brown, does not expressly disclose the specific dimensional and structural refinements recited in these dependent claims. Hochman discloses a draft tube reactor comprising a flow deflector mounted beneath the draft tube outlet and teaches dimensional relationships between the deflector and draft tube outlet, including spacing and radial extension relationships (col. 2, lines 44–65). Zheng teaches that draft tube diameter, height, and spacing relationships are routinely expressed as ratios relative to reactor dimensions to optimize circulation and hydrodynamics (¶[0045]–[0047]). Claim 4, directed to apertures over 5–10% of the lower portion of the central pipe. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Xie by having aperture over 5% to 10% of the lower part of the height of the central pipe from the lower end aperture because Zheng teaches that introducing small apertures of opening near the lower portion of a draft tube can be used to partially redistribute flow or improve circulation. Therefore, it is within the level of one skill in the art to employ such aperture in order to control flow distribution, based on predictable fluid dynamics principles. Claims 7, 8 and 16, directed to spacing of the deflector at between one and two times the equivalent diameter and to deflector diameter relative to central pipe diameter. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Xiu by providing a deflector beneath the draft tube outlet as taught by Hochman in order to improve circulation and prevent fouling. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the system of Xie by providing a deflector having a diameter at least equal to (or greater than) that of the central because Hochman teaches dimensional relationship in which the deflector outer edge extends radially beyond the draft tube outlet in order to ensure effective flow redirection. Claims 11 and 17, directed to central pipe diameter ratios relative to reactor diameter (0.2–0.9; 0.3-.8), and Claims 12 and 18, directed to height ratios relative to reactor height (0.2-.8; .03–0.7; ). It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Xie central pipe has an equivalent diameter with a ratio of the equivalent diameter of the central pipy to the inside diameter of the reactor chamber of between 0.2 and 0.9 because both Zheng and Hochman teach that the draft tube diameter is routinely selected as a fraction of the reactor diameter to control flow velocity and circulation. Therefore, A person of ordinary skill would have recognized the selecting the ratio of 0.2-0.9 falls within normal design practice and provides predictable flow outcomes. It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the process of Xiu by having the central pipe has a height with a ratio of the height of central pipe to the height of the reactor chamber of between .2 and .8 because both Zheng and Hochman teach that sizing the draft tube height as a fraction of reactor height is a routine design choice for achieving predictable circulation. Therefore, selecting a ratio of 0.2-0.8 would have been a conventional engineering practice to a person of ordinary skill. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to TAM M NGUYEN whose telephone number is (571)272-1452. The examiner can normally be reached Mon - Frid. 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, Prem C Singh can be reached on 571-273-6381. 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. /TAM M NGUYEN/ Primary Examiner, Art Unit 1771
Read full office action

Prosecution Timeline

Jun 22, 2023
Application Filed
Mar 08, 2025
Non-Final Rejection — §103
May 31, 2025
Response Filed
Sep 05, 2025
Final Rejection — §103
Sep 26, 2025
Response after Non-Final Action
Feb 23, 2026
Non-Final Rejection — §103 (current)

Precedent Cases

Applications granted by this same examiner with similar technology

Patent 12595428
PROCESS FOR DEPOLYMERIZATION OF SOLID MIXED PLASTIC
2y 5m to grant Granted Apr 07, 2026
Patent 12589376
CATALYTIC REACTOR FOR CRACKING WAX IN WASTE PLASTIC PROLYSIS PROCESS, CATALYTIC COMPOSITION FOR CRACKING WAX IN WASTE PLASTIC PYROLYSIS PROCESS, AND PRODUCTION METHOD THEREOF
2y 5m to grant Granted Mar 31, 2026
Patent 12589362
SUPPORT, ZEOLITE MEMBRANE COMPLEX, METHOD OF PRODUCING ZEOLITE MEMBRANE COMPLEX, AND SEPARATION METHOD
2y 5m to grant Granted Mar 31, 2026
Patent 12584070
METALLIC BASED HYDROCARBON PYROLYSIS
2y 5m to grant Granted Mar 24, 2026
Patent 12570588
DISTILLATE HYDROCRACKING PROCESS WITH A REVERSE ISOMERIZATION STEP TO INCREASE A CONCENTRATION OF N-PARAFFINS
2y 5m to grant Granted Mar 10, 2026
Study what changed to get past this examiner. Based on 5 most recent grants.

AI Strategy Recommendation

Get an AI-powered prosecution strategy using examiner precedents, rejection analysis, and claim mapping.
Powered by AI — typically takes 5-10 seconds

Prosecution Projections

3-4
Expected OA Rounds
78%
Grant Probability
88%
With Interview (+10.9%)
2y 9m
Median Time to Grant
High
PTA Risk
Based on 963 resolved cases by this examiner. Grant probability derived from career allow rate.

Sign in with your work email

Enter your email to receive a magic link. No password needed.

Personal email addresses (Gmail, Yahoo, etc.) are not accepted.

Free tier: 3 strategy analyses per month