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
The examiner acknowledges Applicant’s response filed on 11/24/2025 containing remarks and amendments to the claims.
The rejections of claims 8, 9, 11, and 14 under 35 USC 112(b) are withdrawn in view of the amendments made to said claims.
Response to Arguments
Applicant's arguments (see Remarks) with respect to the rejection of claims 1, 3, 5, 7-9, 11, and 13-14 over Chang (US 4,086,262), in view of Wolf (Chem. Eng. Technol., 39: 1040-1048), have been fully considered but they are not persuasive.
On page 6, Applicant argues that the conversion of CO2 into CO over a reverse water gas shift catalyst in step (i) of the pending claims is operated at an increased pressure of 1 to 10 MPa, which has the effect of an increased CO2 conversion, and that the combination of Chang and Wolf does not teach the pressure limitation. Applicant asserts that Wolf teaches a reverse water gas shift (RWGS) reaction under “ambient pressure” only, i.e. at about 0.1 MPa (citing page 1041, right-hand column, first sentence the caption “2 Experimental Setup”). Applicant submits that there is “no hint in the combination of Chang and Wolf that working at higher pressures could be envisaged, let alone for achieving the effects of the present disclosure.”
In response, the examiner does not find the argument persuasive. While Wolf demonstrates operation of a RWGS reaction at ambient pressure in a “lab-scale” experiment (see pg. 1041, “2 Experimental Setup”), Chang suggests that the reaction may advantageously be operated at higher pressure conditions for a technical process when the RWGS is followed by a downstream FTS unit typically operating at pressure at 30 bar (3 MPa) (pg. 1046, “5. Considerations with Regard to a Technical Application of RWGS”). Although Wolf does not conduct actual experiments at higher pressures due to equipment limitations, the reference provides an estimation of the influence of pressure on the efficiency over a range of 1-30 bar (0.1-3 MPa) (see Figure 10). Therefore, Chang is considered to suggest that workable pressure conditions for the RWGS reaction include a range of 0.1-3 MPa, rather than being limited to ambient pressure. Furthermore, no evidence of criticality or unexpected results associated with the claimed pressure range has been provided. Therefore, the asserted advantage is deemed a conclusory statement lacking factual support.
On page 7, Applicant contends that neither Chang nor Wolf discloses an active and purposive cooling from a temperature of ≥500°C to a temperature of ≤350°C between an RWGS and a subsequent Fischer-Tropsch reaction.
In response, the examiner is not persuaded. As set forth in the rejection, Wolf teaches cooling the RWGS effluent downstream of the reactor which operates at temperatures between 600°C and 1000°C (pg. 1041, “2 Experimental Setup”). Chang further expressly discloses that the reaction conditions for the Fischer-Tropsch process include a temperature of from about 400°F to 1000°F, preferably from about 500°F to 850°F, i.e., about 260-454°C (col. 9, lines 51-53). Accordingly, one of ordinary skill in the art would have been motivated to operate a cooling step such that the syngas product, initially at a temperature between 600°C and 1000°C, is sufficiently cooled to a temperature suitable for the downstream Fischer-Tropsch process, e.g., about 260-454°C. The claimed range of “≤350°C” overlaps with the temperature range taught by Chang and is considered prima facie obvious.
The following is a modified prior art rejection based on the amendments made to the claims.
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.
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, 7-9, 11, 13, and 14 are rejected under 35 U.S.C. 103 as being unpatentable over Chang et al. (US 4,086,262), in view of Wolf et al. (“Syngas Production via Reverse Water-Gas Shift Reaction over a Ni-Al2O3 Catalyst: Catalyst Stability, Reaction Kinetics, and Modeling .” Chem. Eng. Technol. 2016, 39, No. 6, 1040–1048).
Regarding claim 1, Chang discloses a process for converting synthesis gas to hydrocarbon mixtures, the process comprising:
contacting synthesis gas (CO + H2) with a catalyst mixture comprising a Fischer-Tropsch catalyst and a zeolite-based catalyst to produce hydrocarbons comprising aromatics (col. 2, lines 42-53; col. 4, lines 22-29; col. 5, lines 20-31).
Chang discloses that the reaction conditions include a temperature of from about 400°F to 1000°F, preferably from about 500°F to 850°F, i.e., about 260-454°C (col. 9, lines 51-53). The claimed range of “200 to 350°C” overlaps the temperature range taught by Chang and is considered prima facie obvious. In the case where the claimed ranges “overlap or lie inside ranges disclosed by the prior art” a prima facie case of obviousness exists. MPEP 2144.05. I.
Although Chang discloses employing a Fischer-Tropsch catalyst and a zeolite catalyst in a mixture, the reference suggests that the process first involves the reduction of carbon monoxide to hydrocarbons over the Fischer-Tropsch catalyst, followed by the conversion to higher hydrocarbons including aromatics over the zeolite catalyst (col. 2, lines 7-14; col. 4, lines 40-44; col. 5, lines 48-52). It is noted that the instant disclosure discloses an example where a mixture of a Fischer-Tropsch catalyst and a zeolite catalyst is used to carry out the conversion of syngas to hydrocarbons comprising aromatics, which correspond to steps (ii) and (iii) of claim 1 (Spec., pg. 15, lines 11-21). It is further noted that Chang and the instant disclosure use the same type of catalyst (i.e., a supported iron/cobalt catalyst and a HZSM-5 zeolite catalyst) and overlapping operating conditions (Chang: col. 4, lines 40-44, col 7, lines 59-62, col. 9, lines 51-59; Spec, pg. 9, lines 14-17, pg. 9, line 28-pg. 10, line 1; pg. 13, line 10-24). Thus, the conversion of syngas to hydrocarbons over a catalyst mixture comprising a Fischer-Tropsch catalyst and a zeolite-based catalyst taught by Chang is considered to correspond to the claimed limitations “(ii) converting CO from step (i) into C1-C6 hydrocarbons using a Fischer-Tropsch catalyst, and (iii) converting C1-C6 hydrocarbons from step (ii) into aromatics using a zeolite-based catalyst, wherein the C1-C6 hydrocarbons comprise ethylene, propylene and/or butylene.” MPEP 2112.01 I.
Chang does not teach converting CO2 into CO using a reverse water gas shift catalyst, wherein the resulting CO is used as part of the synthesis gas to be converted.
However, Wolf, drawn to a method for producing syngas via a reverse water-gas shift reaction over a Ni-Al2O3 catalyst, teaches that such syngas prepared by a reverse water-gas shift (RWGS) reaction is a known source of syngas feedstock in a Fischer-Tropsch process for producing liquid hydrocarbons (pg. 1040, “1 Introduction; see Figure 1). Wolf discloses a method comprising conducting a RWGS reaction using a Ni-Al2O3 catalyst at temperatures between 600°C and 1000°C and cooling the effluent downstream of the RWGS reactor (pg. 1041, “2 Experimental Setup”).
Therefore, before the effective filing date of the instant invention, it would have been obvious to one of ordinary skill in the art to modify Chang by carrying out a reverse water gas shift process with a catalyst to convert carbon dioxide to carbon monoxide, as taught by Wolf, because (i) Change teaches a Fischer-Tropsch process where carbon monoxide is consumed as a feedstock, (ii) Wolf teaches a reverse water gas shift process that can be used as a source of carbon monoxide for a Fischer-Tropsch process, and (iii) this merely involves application of a known prior art process to provide a source of a feedstock to another known prior art process to yield predictable results.
While Wolf demonstrates operation of a RWGS reaction at ambient pressure in a “lab-scale” experiment (see pg. 1041, “2 Experimental Setup”), the reference does not explicitly teach that the reverse water gas shift is operated at an absolute pressure of 1 to 10 MPa.
However, Wolf teaches that for a technical process, elevated pressures may be advantageous when followed by a downstream process operating at a higher pressure (e.g., 30 bar) (pg. 1046, “5 Consideration with Regard to a Technical Application of RWGS”). Although Wolf does not conduct actual experiments at higher pressures due to equipment limitations, the reference provides an estimation of the influence of pressure on the efficiency over a range of 1-30 bar (0.1-3 MPa) (see Figure 10). Therefore, Chang is considered to suggest that workable pressure conditions for the RWGS reaction include a range of 0.1-3 MPa, rather than being limited to ambient pressure. The claimed range of 1-10 MPa overlaps the pressure range suggested by Wolf and is considered prima facie obvious, in the absence of showing of criticality or unexpected results.
Chang, in view of Wolf, does not explicitly teach a cooling step in which CO produced from the RWGS process is cooled from a temperature of ≥500°C to a temperature of ≤350°C before carrying out the Fischer-Tropsch process.
However, Wolf teaches cooling the RWGS effluent downstream of the reactor which operates at temperatures between 600°C and 1000°C (pg. 1041, “2 Experimental Setup”). and Chang further expressly discloses that the reaction conditions for the Fischer-Tropsch process include a temperature of from about 400°F to 1000°F, preferably from about 500°F to 850°F, i.e., about 260-454°C (col. 9, lines 51-53). Therefore, one would have been motivated to operate a cooling step such that the syngas product, initially at a temperature between 600°C and 1000°C, is sufficiently cooled to a temperature suitable for the downstream Fischer-Tropsch process, e.g., about 260-454°C. The claimed range of “≤350°C” overlaps with the temperature range taught by Chang and is considered prima facie obvious.
Regarding claim 3, Wolf discloses conducting a RWGS reaction at temperatures between 600°C and 1000°C (pg. 1041, “2 Experimental Setup”).
Regarding claim 5, Wolf teaches that water is a byproduct of the reverse water gas shift reaction and is removed during the cooling step downstream of the RWGS reactor (pg. 1041, “2 Experimental Setup”).
Regarding claim 7, Wolf discloses a catalyst comprising nickel (pg. 1041, “2 Experimental Setup”).
Regarding claim 8, Chang teaches that the Fischer-Tropsch catalyst may comprise iron or cobalt (col. 4, lines 40-44).
Regarding claim 9, Chang teaches that the zeolite-based catalyst comprises an MFI zeolite (ZSM-5), an MEL zeolite (ZSM-11), or an MTW zeolite (ZSM-12) (col. 7, lines 14-16).
Regarding claim 11, Chang, in view of Wolf, does not explicitly teach that the Fischer Tropsch step additionally produces saturated C7+ hydrocarbons. However, Chang and the instant disclosure use the same type of catalyst (i.e., a supported iron/cobalt catalyst and a HZSM-5 zeolite catalyst) and overlapping operating conditions (Chang: col. 4, lines 40-44, col 7, lines 59-62, col. 9, lines 51-59; Spec, pg. 9, lines 14-17, pg. 9, line 28-pg. 10, line 1; pg. 13, line 10-24). Thus, the Fischer-Tropsch step taught by Chang is expected to produce saturated C7+ hydrocarbons.
Regarding claim 13, Wolf is silent on having CO in the CO2 feed and thus is considered to suggest that the CO2 feed is at least substantially free of CO.
Regarding claim 14, Wolf discloses a method comprising conducting a RWGS reaction reacting CO2 and H2 over a Ni-Al2O3 catalyst at temperatures between 600°C and 1000°C to produce an effluent comprising carbon monoxide and water and cooling the effluent downstream of the RWGS reactor, where water byproduct is removed from the cooling step (pg. 1040-1041, “1 Introduction” and “2 Experimental Setup”). In the modified Chang/Wolf process, the carbon monoxide so produced in Wolf is used as feedstock in a Fischer-Tropsch process of Chang. Chang teaches that the zeolite-based catalyst comprises an MFI zeolite (ZSM-5), an MEL zeolite (ZSM-11), or an MTW zeolite (ZSM-12) (col. 7, lines 14-16).
Chang, in view of Wolf, does not explicitly teach that the Fischer Tropsch step produces saturated C8+ hydrocarbons and unsaturated hydrocarbons comprising ethylene, propylene and/or butylene. However, Chang and the instant disclosure use the same type of catalyst (i.e., a supported iron/cobalt catalyst and a HZSM-5 zeolite catalyst) and overlapping operating conditions (Chang: col. 4, lines 40-44, col 7, lines 59-62, col. 9, lines 51-59; Spec, pg. 9, lines 14-17, pg. 9, line 28-pg. 10, line 1; pg. 13, line 10-24). Thus, the Fischer-Tropsch step taught by Chang is expected to have the same or substantially the same result as the claimed invention, including the production of saturated C8+ hydrocarbons and unsaturated hydrocarbons comprising ethylene, propylene and/or butylene.
Claim 10 is rejected under 35 U.S.C. 103 as being unpatentable over Chang et al. (US 4,086,262), in view of Wolf et al. (“Syngas Production via Reverse Water-Gas Shift Reaction over a Ni-Al2O3 Catalyst: Catalyst Stability, Reaction Kinetics, and Modeling .” Chem. Eng. Technol. 2016, 39, No. 6, 1040–1048), as applied to claim 1, and further in view of Okemoto et al. (“Catalytic performance of MoO3/FAU zeolite catalysts modified by Cu for reverse water gas shift reaction.” Applied Catalysis A, General 592 (2020) 117415).
Regarding claim 10, Chang, in view of Wolf (“Chang/Wolf”), teaches the method of claim 1, as discussed above.
Chang/Wolf does not teach that another metal-modified zeolite-based catalyst is present in the reverse water gas shift reaction.
However, Okemoto teaches a Mo-Cu modified-FAU zeolite catalyst effective for a reverse water gas shift process that converts carbon dioxide to carbon monoxide (Abstract; pg. 24, “2. Experimental” and “3.1 Catalytic test for the RWGS reaction”).
Therefore, before the effective filing date of the instant invention, it would have been obvious to modify the Chang/Wolf process by including a Mo-Cu modified-FAU zeolite catalyst of Okemoto in the reverse water gas shift process, because Chang/Wolf and Okemoto both teach an effective catalyst for reverse water gas shift reaction and it is prima facie obvious to combine equivalents for the same purpose. MPEP 2144.06 I.
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 JASON Y CHONG whose telephone number is (571)431-0694. The examiner can normally be reached Monday-Friday 9:00am-5:30pm.
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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.
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/JASON Y CHONG/Examiner, Art Unit 1772
/IN SUK C BULLOCK/Supervisory Patent Examiner, Art Unit 1772