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
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 1–2 and 4–9 are rejected under 35 U.S.C. 103 as being unpatentable over Liu et al. (US 2021/0379549 A1) in view of Nagaki et al. (US 2016/0362351 A1) and Basset et al. (US 2013/0224106 A1), and further in view of Guo et al., “Direct, Nonoxidative Conversion of Methane to Ethylene, Aromatics, and Hydrogen,” Science, Vol. 344, pp. 616–619 (2014).
Regarding claim 1, Liu teaches direct nonoxidative methane conversion in a catalytic-wall reactor. Liu teaches introducing methane into a catalytic reactor and producing coke, C₂+ hydrocarbons and hydrogen, wherein the C₂+ hydrocarbons include acetylene, ethylene, ethane, benzene, toluene and naphthalene; Liu further teaches operating the reactor at about 1170–1370 K and controlling methane flow rate and temperature to regulate methane conversion and product selectivity (Liu ¶[0015]; Figs. 1, 2A–2B, 3A–3D; claims 21–31).
Liu thus teaches a methane-conversion reactor producing acetylene, ethylene and aromatic hydrocarbons and producing coke/carbon during the methane-conversion reaction, but does not expressly teach dividing the reaction unit into the claimed first and second reaction zones, supporting a metal compound on the carbon layer in the second zone, or expressly reporting the methane-conversion activation energy of the carbon layer.
Nagaki teaches a methane-conversion reactor having a preheat zone, primary reaction zone, secondary reaction zone and quench zone (Nagaki ¶[0045]; Figs. 3–8). Nagaki expressly states that nonoxidative methane conversion produces hydrogen, ethylene, ethane, acetylene and higher hydrocarbons, including benzene and naphthalene (¶[0047]). Nagaki further teaches that final product selectivity can be controlled by the residence time and temperature profile of the secondary reaction zone, and that conversion/selectivity are affected by feed composition, catalyst composition, contact time, secondary-zone temperature and secondary-zone residence time (¶¶[0193]–[0194]).
Nagaki additionally teaches staged hydrogen addition. The volumetric ratio of hydrogen to the feed/reactant mixture may be about 0.01:1–10:1, 0.1:1–5:1, or 0.5:1–2:1 (¶[0059]), and staged hydrogen addition permits control of surface-radical formation, gas-phase reactions, conversion and selectivity (¶[0060]). Nagaki specifically teaches adding a greater amount of hydrogen to the secondary reaction zone, where hydrogen increases selectivity to lighter hydrocarbons by promoting hydrocracking and hydrogenation reactions (¶[0063]).
Guo teaches direct nonoxidative methane conversion to ethylene and aromatics and explains that the reaction is initiated by catalytic generation of methyl radicals followed by gas-phase reactions (Guo, p. 616, left col. to right col.). Guo further teaches that CH₄ activation produces CHx species which form C₂Hy intermediates and subsequently benzene and naphthalene, and that methane is converted to ethylene, benzene and naphthalene under nonoxidative conditions (Guo, p. 616, right col.). Guo also teaches that noncatalytic methane pyrolysis is dominated by acetylene accompanied by high coke formation (Guo, p. 617, left col.).
Basset teaches use of metal catalysts including Ru, Ni, Fe, Cu, Co, Pd and Pt, and expressly teaches that the metal catalyst may be supported on a solid support including graphite (Basset ¶[0015]).
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 Liu’s methane-conversion reactor to include separate first and second reaction zones as taught by Nagaki, because Nagaki teaches that secondary-zone temperature and residence time may be controlled independently to control final product selectivity
It would have been further obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have modified the downstream reaction zone of Liu’s methane-conversion reactor to introduce hydrogen as taught by Nagaki, because Nagaki teaches that hydrogen may be added to the secondary reaction zone and that such hydrogen addition increases selectivity to lighter hydrocarbons by promoting hydrocracking and hydrogenation reactions (Nagaki ¶[0063]). Applying Nagaki’s hydrogen-addition teaching to Liu’s reactor would have provided a known means for promoting downstream conversion of C₂ intermediates and controlling product selectivity. Guo further establishes that high-temperature methane pyrolysis readily produces acetylene and coke, while nonoxidative methane conversion chemistry produces ethylene and aromatic hydrocarbons, thereby providing a reasonable expectation that Liu’s high-temperature methane-conversion products could be further converted in a downstream hydrogen-containing reaction zone to obtain the desired ethylene and aromatic products.
It would have been further obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have supported a known hydrogenation-active metal such as Pd, Pt, Ni or Fe on the carbonaceous layer in the downstream reaction zone, because Basset expressly teaches these metals supported on a carbon material such as graphite (Basset ¶[0015]), thereby providing a supported catalytic metal at the reaction surface.
Claim 1 has been amended to require that the carbon layer has a methane-conversion activation energy of 300–380 kJ/mol.
The applied references do not expressly report this numerical property. However, the claimed activation energy is a kinetic property of the carbon layer, rather than a separately added structural component or independently selected reactor operating condition.
Liu forms coke/carbon during substantially the same direct nonoxidative methane-conversion chemistry while producing acetylene, ethylene and aromatic hydrocarbons at about 1170–1370o K. Liu further teaches controlling temperature and methane flow to regulate conversion and selectivity. Nagaki likewise teaches nonoxidative methane conversion at high temperature and expressly recognizes acetylene, ethylene and aromatic hydrocarbons as products (¶[0047]).
The present specification itself establishes that activation energy is determined by measuring methane reactivity of the already-formed carbon layer and applying an Arrhenius analysis. Experimental Example 1 reports activation energies of approximately 325.6, 364.3 and 372.8 kJ/mol for different portions of the carbon layer (present specification ¶¶[0089]–[0091]; Fig. 3).
Because the prior art forms a carbon/coke layer by substantially the same nonoxidative methane-conversion chemistry under substantially overlapping high-temperature conditions, the resulting carbon layer would reasonably be expected to possess the corresponding methane-conversion kinetic characteristics. Recitation of an unreported property of an otherwise substantially identical material does not patentably distinguish the material absent evidence that the prior-art material is materially different. See In re Best, 562 F.2d 1252, 1255, 195 USPQ 430, 433–34 (CCPA 1977); In re Spada, 911 F.2d 705, 708, 15 USPQ2d 1655, 1657–58 (Fed. Cir. 1990).
Regarding claim 2, Liu expressly teaches coke formation during direct methane conversion and identifies coke as one of the products produced together with C₂+ hydrocarbons and hydrogen (Liu claims 21–24; Figs. 2A and 3D). Thus, Liu teaches or suggests the claimed coke/carbon layer formed by the nonoxidative methane-conversion reaction.
Regarding claim 4, Basset expressly teaches metal catalysts comprising ruthenium, nickel, iron, copper, cobalt, palladium and platinum, including several metals recited in claim 4, and teaches that such catalysts can be supported on graphite (Basset ¶[0015]).
Regarding claim 5, Nagaki teaches adding hydrogen to the methane-containing reactant mixture and expressly teaches a volumetric ratio of hydrogen to the feed/reactant mixture of about 0.01:1–10:1, 0.1:1–5:1, or 0.5:1–2:1 (Nagaki ¶[0059]), which overlaps the claimed H₂/CH₄ ratio of 1.1–5.0. Nagaki teaches that hydrogen addition controls surface-radical formation, gas-phase reactions, conversion and selectivity and may be staged through the reactor (¶¶[0060]–[0063]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have selected an overlapping hydrogen-to-methane ratio to obtain the conversion and product selectivity expressly taught by Nagaki.
Regarding claim 6, Nagaki teaches a catalyzed reaction-zone temperature of about 900–1150°C, which lies within the claimed 900–1300°C range (Nagaki ¶[0214]). Nagaki further teaches a primary-zone pressure of about 0.1–40 bar, 1–20 bar, or 2–10 bar (¶¶[0098]–[0099]). Thus, Nagaki expressly teaches operating conditions overlapping both the claimed temperature and the claimed pressure of 10 bar or less.
Regarding claim 7, Nagaki teaches adding hydrogen to the secondary reaction zone at approximately the secondary-zone temperature, e.g., about 700–1300°C (¶[0063]), which overlaps the claimed 30–900°C range. Nagaki further teaches a total reactor pressure of about 0.1–40 bar, 1–20 bar, or 2–10 bar, and expressly teaches controlling the pressure of each zone to achieve desired conversion and/or selectivity (¶¶[0176]–[0177]).
Accordingly, Nagaki teaches overlapping secondary-zone temperature and pressure ranges.
Regarding claim 8, Nagaki expressly teaches a reactor GHSV of about 1,000–500,000 h⁻¹, alternatively 1,500–100,000 h⁻¹, 2,000–50,000 h⁻¹, or 4,000–25,000 h⁻¹, and teaches selecting GHSV to obtain desired conversion and/or selectivity (Nagaki ¶[0181]). These ranges overlap the claimed 1,000–6,000 h⁻¹.
Accordingly, selection of the claimed overlapping GHSV would have been obvious.
Regarding claim 9, Nagaki expressly teaches that the reactor may be characterized by a weight hourly space velocity (WHSV) of about 1,000–500,000 h⁻¹, alternatively about 1,500–100,000 h⁻¹, about 2,000–50,000 h⁻¹, or about 4,000–25,000 h⁻¹, and further teaches that the WHSV may be selected to achieve a desired conversion and/or selectivity (Nagaki ¶[0182]).
It would have been obvious to one having ordinary skill in the art before the effective filing date of the claimed invention to have operated the second reaction zone of the modified Liu reactor at an effective WHSV, including the claimed WHSV range, because Nagaki expressly teaches WHSV as a reactor operating parameter affecting conversion and product selectivity.
Response to Arguments
Applicant argues that the prior rejection merely identifies claim elements in separate references without providing an adequate reason why one having ordinary skill would have combined Liu, Nagaki, Basset and Guo.
The argument has been considered but is not persuasive. The rejection has been clarified above. Liu teaches direct nonoxidative methane conversion producing coke, acetylene, ethylene and aromatic hydrocarbons. Nagaki expressly teaches separating methane conversion into primary and secondary reaction zones, and further teaches that secondary-zone residence time and temperature control final product selectivity (Nagaki ¶¶[0193]–[0194]). Nagaki additionally teaches staged hydrogen addition, including greater hydrogen addition to the secondary zone to promote hydrogenation reactions and increase lighter-hydrocarbon selectivity (¶[0063]). Thus, the modification is not based merely on the separate existence of individual claim elements; Nagaki provides an express technical reason for using separate reaction zones and controlling downstream hydrogenation conditions.
Guo further establishes that high-temperature methane pyrolysis produces acetylene and coke, whereas nonoxidative methane chemistry is known to yield ethylene and aromatic hydrocarbons (Guo, pp. 616–617). Basset provides the known use of hydrogenation-active metals, including Pd, Pt, Ni and Fe, supported on carbonaceous graphite (Basset ¶[0015]). Accordingly, the cited teachings provide both a reason to make the proposed modifications and a reasonable expectation of obtaining the predictable methane-conversion products.
Applicant further argues that the cited references do not disclose or suggest the amended limitation that the carbon layer has a methane-conversion activation energy of 300–380 kJ/mol is not persuasive. The rejection instead relies on the principle that an unreported property does not distinguish an otherwise identical or substantially identical material produced by an identical or substantially identical process. The present specification itself confirms that the activation energy is a measured kinetic property of the carbon layer after formation; Experimental Example 1 measures methane reactivity of the layer and obtains activation energies of about 325.6, 364.3 and 372.8 kJ/mol (Specification ¶¶[0089]–[0091]; Fig. 3). Liu and Nagaki form carbon/coke during substantially the same high-temperature nonoxidative methane-conversion chemistry and under overlapping conditions. Therefore, the Office has a reasonable basis for concluding that the resulting prior-art carbon layer possesses corresponding methane-conversion kinetic properties. Under In re Best and In re Spada, where the claimed and prior-art materials appear identical or substantially identical or are produced by substantially identical processes, Applicant bears the burden of establishing that the prior-art material does not possess the claimed property.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). 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 TAM M NGUYEN whose telephone number is (571)272-1452. The examiner can normally be reached Mon - Frid.
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/TAM M NGUYEN/Primary Examiner, Art Unit 1771
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