20DETAILED 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
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 1-20 are rejected under 35 U.S.C. 103 as being unpatentable over Washburn et al. (WO 2020/197890 A1) in view of Dorsi et al. (US 2021/0122688 A1).
Washburn teaches a process for producing p-xylene by methylation of benzene and/or toluene with methanol and/or dimethyl ether in the presence of a zeolitic methylation catalyst, including MWW-type zeolites, under methylation conditions of temperature and pressure consistent with those recited in the claims (See [0089]-[0094], [0090]-[0091]).
Washburn further teaches:
operation in fixed-bed reactors, including multiple catalyst beds arranged in series ([0083]-(0084);
staged addition of methylating agent and/or aromatic feed ([0091]);
formation of water as a reaction by-product of methylation ([0031]); and
removal of water and other components from methylation effluent using conventional separation techniques, producing aromatic-rich stream ([0095]-[0096]).
Accordingly, Washburn teaches the core methylation process of claims 1, 3–5, 10–15, and 18–19, except for the specific interstage processing and recycle architecture recited in certain dependent claims.
Dorsi teaches an integrated methylation process for producing p-xylene from benzene and/or toluene with methanol and/or dimethyl ether, including:
fixed-bed methylation reactors ([0034], [0035];
operating temperatures (200–500 °C) and pressures (100–8,500 kPa) ([0031]-[0032]);
aqueous/oil phase separation of methylation effluent to remove reaction water ([0042], [0049]);
recovery of DME-rich, methanol-rich, and aromatics-rich streams ([0043]-[0047];
recycling of DME, methanol, benzene, and/or toluene to the methylation reactor ([0043], [0047], [0049], [0050]; and
heat exchange (cooling/heating) of reactor effluent prior to separation ([0078]-[0081]).
Dorsi therefore expressly teaches interstage separation, conditioning, and recycle of methylation effluent streams.
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to incorporate the effluent separation, water removal, and recycle techniques of Dorsi into the methylation process of Washburn because:
Both references are in the same field (benzene/toluene methylation to p-xylene using methanol/DME and zeolitic catalysts);
Both recognize water and unreacted methylating agent as normal products/by-products of methylation;
Removal of water and recycling of unreacted methanol/DME and aromatics are well-known process-efficiency and catalyst-protection measures; and
The modification represents a predictable combination of known process steps yielding expected benefits (improved catalyst life, improved feed utilization, reduced separation load).
Claim 2
Washburn teaches a multi-stage methylation process employing staged reactors and temperature control of methylation effluent prior to downstream handling and separation (¶¶ [0093], [0095]–[0096]). However, Washburn does not expressly quantify an interstage temperature differential.
Dorsi explicitly teaches cooling methylation effluent using heat exchangers prior to further processing, including cooling prior to separation and recycle, which necessarily results in a temperature reduction between reaction stages (¶¶ [0078]–[0081], [0034]–[0036]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to apply the effluent cooling techniques of Dorsi to the staged methylation process of to control reaction severity and catalyst performance, thereby arriving at the claimed interstage temperature reduction, which represents a result-effective variable.
Claim 3
Washburn explicitly teaches methylation reaction temperatures within 200–500 °C (¶¶ [0089]–[0091]).
Claim 4
Washburn discloses preferred methylation temperatures within sub-ranges overlapping 250–400 °C (¶¶ [0089]–[0090]).
Claim 5
Washburn teaches staged addition of methylating agent to control reaction severity and selectivity (¶ [0093]). Injection of a methylating agent at a lower temperature than the reactor bed inherently produces a temperature differential, with the specific ΔT being a result-effective variable.
Claims 6–9
Washburn teaches that methylation produces water as a by-product and that methylation effluent is subjected to separation to remove water and other components (¶¶ [0095]–[0096]).
Dorsi explicitly teaches:
cooling methylation effluent prior to separation using heat exchangers (¶¶ [0034]–[0035], [0078]–[0081]);
aqueous/oil phase separation to remove water (¶¶ [0034]–[0036]).
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 Washburn by combining these teachings to achieve predication removal of water and conditioning of efferent stream. Claims 10–15
Washburn teaches:
fixed-bed methylation reactors (¶¶ [0083]–[0084]);
pressures within 100–8,500 kPa (¶ [0091]);
zeolitic methylation catalysts including MWW-type and ZSM-5 (¶¶ [0093]–[0094]);
aromatic-to-methylating-agent molar ratios overlapping the claimed ranges (¶ [0091]).
Claims 16–17
Washburn teaches controlling aromatic-to-methylating-agent ratios during methylation (¶ [0091]).
Dorsi explicitly teaches recycling methanol, DME, benzene, and/or toluene from separation units back to the methylation reactor to maintain desired feed ratios (¶¶ [0034]–[0039], [0040]–[0042]).
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 Washburn by recycling streams as suggested by Dorsi to maintain desired ratio ratios (claimed ratio). Claims 18–19
Washburn teaches multiple catalyst beds arranged in series, either within a single reactor or in separate vessels, for methylation reactions ([0083]-[0084]).
Claim 20
Washburn teaches staged methylation reactors with downstream separation of methylation effluent ([0095]–[0096]).
Dorsi explicitly teaches:
separation of methylation effluent into aqueous and hydrocarbon phases (¶¶ [0034]–[0036]);
recovery of aromatics-rich streams (¶ [0033]);
recycle of benzene/toluene-rich streams to the methylation reactor (¶¶ [0039]–[0042], [0040]–[0041]).
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 Washburn by incorporating these known separation and recycle steps of Dorsi into the methylation process of Washburn to improve efficiency and catalyst utilization.
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.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Prem C Singh can be reached at 571-273-6381. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/TAM M NGUYEN/Primary Examiner, Art Unit 1771