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 .
Election/Restrictions
Applicant’s election without traverse of restriction/requirement in the reply filed on 1/6/2026 is acknowledged.
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 1-12 are rejected under 35 U.S.C. 103 as being unpatentable over CN 103160310 A (hereinafter “CN ’310”) in view of Noe (US 2010/0270213 A1) (hereinafter “Noe”).
CN ’310 teaches a composite solvent system for separation of aromatic hydrocarbons from hydrocarbon mixtures, including refinery streams (e.g., naphtha, reformate). CN ’310 discloses solvent systems comprising:
a main solvent selected from sulfolane, N-formylmorpholine (NFM), dimethyl sulfoxide (DMSO), or glycols;
a co-solvent selected from N-methylpyrrolidone (NMP) or dimethylformamide (DMF); and
an optional modifier (e.g., ethylene glycol or polyethylene glycol).
CN ’310 teaches that combining such solvents improves aromatics selectivity and solubility relative to conventional single-solvent systems and is suitable for aromatics separation in refinery operations. CN ’310 further teaches solvent-to-feed ratios and operating conditions within conventional extraction practice.
Noe teaches extractive distillation of aromatics from non-aromatic hydrocarbons using aromatic-selective solvents, including sulfolane (tetramethylene sulfone) and other solvents alone or in combination, such as DMSO, NMP, NFM, and glycols. Noe explicitly teaches:
extractive distillation columns for separating benzene, toluene, and xylenes from paraffinic/naphthenic hydrocarbons;
solvent-to-feed ratios ranging from about 1:1 to about 20:1;
operating temperatures spanning ranges that include about 125 °C to about 150 °C; and
that solvent selection and operating conditions are adjusted to achieve desired separation efficiency.
Although neither CN ’310 nor Noe explicitly quantifies octane-to-benzene relative volatility under the exact test conditions recited in claim 1, relative volatility between aromatic and non-aromatic hydrocarbons is a recognized measure of separation performance in extractive distillation, and temperature, feed composition, and solvent-to-feed ratio are known result-effective variables affecting such performance.
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 CN ’310 by combining the aromatics separation of CN’310 and Noe’s teaching of extractive distillation using those solvents under overlapping operating conditions, to evaluate and optimize the known solvent systems under different feed compositions, temperatures, and solvent-to-feed ratios to achieve improved separation performance relative to sulfolane, including the performance recited in claim 1.
The limitation “consisting essentially of” does not patentably distinguish the claim because any additional components disclosed in the references (e.g., modifiers or water used as process aids) are not shown to materially affect the basic and novel characteristics of the solvent mixture, namely its use for aromatics separation and associated separation performance.
Claim 2 (relative amounts of first and second solvents): CN ’310 teaches solvent composition ranges in which a main solvent is present in a majority amount and a co-solvent is present in a lesser amount, overlapping the claimed ranges. Selection of specific proportions would have been a matter of routine optimization.
Claim 3 (first solvent selected from DMSO, DFP, DMS, EMS): CN ’310 explicitly teaches DMSO as a main solvent for aromatics separation. Selection among known alternative solvents within the same class would have been obvious.
Claim 4 (second solvent selected from TMSO, GBL, furanone, NFM, DVL, NMP, propylene carbonate, DES, 3-MS): CN ’310 teaches NMP and NFM as co-solvents. Noe further teaches sulfolane derivatives and related solvents used in extractive distillation. Selection from these known solvents would have been obvious.
Claim 5 (additives): CN ’310 teaches optional modifiers (e.g., glycols), and Noe teaches use of water or other process aids. The use of additives such as stabilizers or inhibitors in solvent systems is well known.
Claim 6 (specific solvent combinations and ranges): These recite particular combinations and proportions of known solvents taught by CN ’310. Selecting specific combinations and ranges from among known options would have been obvious as a matter of routine experimentation.
Claim 7 recites a solvent mixture for extractive distillation consisting essentially of a base solvent (including sulfolane, NMP, NFM, DMF, glycols), first and second co-solvents, and optional additives, with improved separation performance relative to the base solvent.
CN ’310 teaches base solvents including sulfolane, NFM, DMSO, and glycols, with co-solvents such as NMP. Noe teaches extractive distillation using those same solvents, alone or in combination, under overlapping operating conditions.
Claims 8–12, which further limit solvent ratios, solvent selections, and additives, are unpatentable for the same reasons discussed above: the solvent species and their use in extractive distillation are taught by the references, and selection of specific ratios, combinations, and additives represents routine optimization of known systems.
CN ’310 provides the solvent identities and combinations suitable for aromatics separation, while Noe provides the extractive distillation context and teaches operating those solvents under conditions overlapping those recited in the claims.
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 CN ’310 in the extractive distillation processes taught by Noe, with a reasonable expectation of success, because both references address the same problem of separating aromatic hydrocarbons from non-aromatics in refinery streams. Optimizing performance metrics such as relative volatility by adjusting known result-effective variables would have been obvious.
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