Prosecution Insights
Last updated: April 19, 2026
Application No. 18/690,348

Xylene Isomer Separation Processes

Non-Final OA §103
Filed
Mar 08, 2024
Examiner
VASISTH, VISHAL V
Art Unit
1771
Tech Center
1700 — Chemical & Materials Engineering
Assignee
ExxonMobil
OA Round
1 (Non-Final)
72%
Grant Probability
Favorable
1-2
OA Rounds
2y 6m
To Grant
99%
With Interview

Examiner Intelligence

Grants 72% — above average
72%
Career Allow Rate
966 granted / 1337 resolved
+7.3% vs TC avg
Strong +33% interview lift
Without
With
+33.3%
Interview Lift
resolved cases with interview
Typical timeline
2y 6m
Avg Prosecution
51 currently pending
Career history
1388
Total Applications
across all art units

Statute-Specific Performance

§101
0.9%
-39.1% vs TC avg
§103
50.1%
+10.1% vs TC avg
§102
15.9%
-24.1% vs TC avg
§112
11.4%
-28.6% vs TC avg
Black line = Tech Center average estimate • Based on career data from 1337 resolved cases

Office Action

§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 . Claim Rejections - 35 USC § 103 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. Claims 1-24 are rejected under 35 U.S.C. 103 as being unpatentable over Pilliod et al., International Publication No. WO/2012/058106 (hereinafter referred to as Pilliod) in view of Corradi, US Patent Application Publication No. 2013/0158330 (hereinafter referred to as Corradi). Regarding claims 1-4 and 6-24, Pilliod discloses a process for the production of purified xylene whereby a feed comprising C8+ aromatics is first fractionated into a first stream comprising paraxylene and metaxylene and a second stream comprising orthoxylene and C9+ aromatics. The orthoxylene and the C9+ aromatics are further fractioned in fractionator (16). The paraxylene is recovered and implicitly separated from metaxylene in paraxylene recovery unit (12) of figure 2. Crystallization or selective adsorption is used to separated paraxylene (see Claims 1-15; Para. [0007] and [0030]- [0038] and see Figure 2). Pilliod discloses all the limitations discussed above but does not explicitly disclose a third and fourth stream comprising p-xylene and m-xylene respectively as recited in claims 1 and 21. Corradi discloses a process for separating para-xylene from a plurality of xylene isomers, wherein the process introduces at a first feed point a first mixed xylene stream comprising a plurality of xylene isomers into a first adsorptive separation unit to produce a first para-xylene enriched stream and a first raffinate stream, and introduces a second mixed xylene stream comprising a plurality of xylene isomers into a second adsorptive separation unit to produce a second raffinate stream. The process feeds both the first raffinate stream and the second raffinate stream into a raffinate column. The process further introduces an extract stream from the second adsorptive separation unit into a first input of a split extract column comprising an internal partition defining a first distillation zone and a second distillation zone wherein the fractional distillation column, further comprising: a first plurality of distillation trays disposed in said first distillation zone; a second plurality of distillation trays disposed in said second distillation zone; and wherein at least four distillation trays are disposed between said first input port and said top portion of said partition (see Abstract and see Claims 10-16). Corradi further discloses the para-xylene isomers are then separated from the C8 isomer admixture using a simulated countercurrent moving-bed (SMB) adsorptive separation unit. This simulation is performed using established commercial technology wherein an adsorbent, commonly a solid zeolitic material, is held in place in one or more cylindrical adsorbent chambers. The positions at which the streams involved in the process enter and leave the chamber(s) are slowly shifted along the height of the chamber(s). Normally there are at least four streams (feed, desorbent, extract and raffinate) employed in this procedure and the location at which the feed and desorbent streams enter the chamber and the extract and raffinate streams leave the chamber are simultaneously shifted in the same direction at set intervals in a step-wise manner. Each shift in location of these transfer points delivers or removes liquid from a different bed within the chamber (Para. [0016]). It would have been obvious to one of ordinary skill in the art at the time of the invention to use the process and apparatus of Corradi in the process of Pilliod combining prior art elements according to known methods to yield predictable results. Regarding claim 5, Pilliod/Corradi disclose all the limitations discussed above but do not explicitly disclose the specific limitations of claim 5. This is common knowledge to one of ordinary skill in the art at the time of the invention. It is known a better separation between the close boiling components a tray-based distillation column having more separation trays. Likewise, when the aim is a better separation between the meta-xylene and the para-xylene on the one hand and ortho-xylene on the other hand the skilled person would know how to operate the column, for example by using a high reflux. Separation between meta-xylene and para-xylene is also obvious. Also, the feed streams can arise from several sources as has been indicated in paragraph [0007] of Pilliod. The skilled person would, based on this document know that isomerization and recycling are common steps in the field, which are obvious in the absence of an effect related to them. Conclusion Any inquiry concerning this communication or earlier communications from the examiner should be directed to VISHAL V VASISTH whose telephone number is (571)270-3716. The examiner can normally be reached M-F 9:00-4:30 and 7:00-10:00p. 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, Prem Singh can be reached at 5712726381. 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. /VISHAL V VASISTH/Primary Examiner, Art Unit 1771
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Prosecution Timeline

Mar 08, 2024
Application Filed
Feb 18, 2026
Non-Final Rejection — §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

1-2
Expected OA Rounds
72%
Grant Probability
99%
With Interview (+33.3%)
2y 6m
Median Time to Grant
Low
PTA Risk
Based on 1337 resolved cases by this examiner. Grant probability derived from career allow rate.

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