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 .
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on May 26, 2026 has been entered.
Detailed Action
This office action is a response to applicant’s communication submitted May 26, 2026, wherein claim 2 is amended and new claim 63 is introduced. This application is a national stage application of PCT/US2002/059292, filed November 6, 2020, which claims benefit of provisional application 62/932038, filed November 7, 2019.
Claims 2 and 58-63 are pending in this application.
Claims 2 and 58-63 as amended are examined on the merits herein.
Withdrawn Rejections
Applicant’s amendment, submitted May 26, 2026, with respect to the rejection of claims 2 and 58-61 under 35 USC 103 for being obvious over Buchanan et al. in view of Stabel et al. in view of Akah et al. in view of Angyal et al. in view of Subramani et al., has been fully considered and found to be persuasive to remove the rejection as the claims have been amended to require that the steam be present at a specific weight ratio to the hydrocarbon. Therefore the rejection is withdrawn.
The rejection of claims 2 and 58-62 for claiming the same invention as claims 3, 4, 7, 8, and 17 of US patent 12338211 in view of Buchanan et al. in view of Dwidar et al. in view of Subramani et al. in view of Angyal et al., is withdrawn in view of the terminal disclaimer submitted May 26, 2026.
The rejection of claims 2, 58, and 60 for claiming the same invention as claims 1-8 of US patent 12312540 in view of Buchanan et al. in view of Dwidar et al. in view of Subramani et al. in view of Angyal et al., is withdrawn in view of the terminal disclaimer submitted May 26, 2026.
The rejection of claims 2 and 58-62 for claiming the same invention as claims 1, 2, 4, and 11 of US application 16/881030 in view of Buchanan et al. in view of Dwidar et al. in view of Subramani et al. in view of Angyal et al., is withdrawn in view of the terminal disclaimer submitted May 26, 2026.
The rejection of claims 2 and 58-62 for claiming the same invention as claim 33 of US application 17/595510 in view of Buchanan et al. in view of Dwidar et al. in view of Subramani et al. in view of Angyal et al., is withdrawn in view of the terminal disclaimer submitted May 26, 2026.
The following new grounds of rejection are introduced:
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.
Claims 2, 58-61, and 63 are rejected under 35 U.S.C. 103 as being unpatentable over Buchanan et al. (US pre-grant publication 2012/0238742, of record in previous action) in view of Stabel et al. (US patent 5731483, cited in PTO-1449 submitted August 24, 2022) in view of Akah et al. (Reference of record on previous action) in view of Angyal et al. (Reference of record in previous action) in view of Dwidar et al. (Reference of record in previous action) in view of Subramani et al. (US pre-grant publication 2013/0056393, of record in previous action) in view of Gal et al. (Reference included with PTO-892)
Independent claim 2 claims a process for making a cellulose ester composition comprising steps of pyrolyzing a plastic waste, feeding the resulting pyrolysis oil into a steam cracker in combination with a non-recycle hydrocarbon, processing the olefin effluent by one of several further reactions to produce butyric acid or butyric anhydride, and reacting said reactant with cellulose to produce a cellulose ester. Dependent claim 58 further specifies that the cellulose ester is cellulose acetate butyrate. As presently amended, claim 2 requires that the recycled pyoil be a specific percentage of the total hydrocarbon feedstock, and additionally that the total ratio of steam to hydrocarbons be within a specific range.
Buchanan et al. discloses a process for producing a cellulose ester comprising dissolving cellulose in an ionic liquid, and then esterifying the cellulose in the ionic liquid. (p. 1 paragraph 9) The process further comprises adding a carboxylate donor to the ionic liquid, which can include a C2-C4 straight chain carboxylic acid, from which one skilled in the art would at once envisage butyric acid, or an anhydride such as butyric anhydride. (p. 5 paragraphs 55-56, p. 7 paragraph 77) The cellulose ester can be a mixed ester, containing ester groups selected from a list including acetate and butyrate. (p. 10 paragraph 92) In particular, cellulose acetate butyrate is described as one of the mixed esters that can be produced by this process. (p. 12 paragraphs 107 and 108) Buchanan et al. does not specifically describe the source of the butyric acid or butyric anhydride.
Stabel et al. discloses a method for converting waste plastic to feed materials for steam cracking. (column 1 lines 9-25) The plastic waste is melted and fed into a reactor at high temperature, in a process that is reasonably considered to be pyrolysis and to result in pyrolysis oil. (column 2 lines 28-50) The products of this steam cracking process include propylene. (column 2 lines 25-27, column 7 example 1)
Akah et al. discloses that propylene is typically obtained as a byproduct of steam cracking of feedstocks, including feed alkanes such as ethane and propane. (p. 266 left column second paragraph, also table 1) Angyal et al. discloses that steam cracking feedstocks can be derived by mild cracking (pyrolysis) of various plastic wastes. (p. 1718 left column second paragraph) Results of the initial pyrolysis included gas, distillate, and oil. (p. 1718 left column second paragraph) The products of steam cracking included propylene. (p. 1722 table 3) Dwidar et al. discloses that butyric acid can be produced by transformation of propylene into butyraldehyde, which is then transformed into butyric acid. (p. 2 section 2)
It would therefore have been obvious to one of ordinary skill in the at the time of the invention to use pyrolysis of waste plastic and subsequent steam cracking of the resulting pyrolysis oil to produce propylene, which could then be subject to chemical conversion to butanoic acid to produce butanoic acid for use in the process described by Buchanan et al. One of ordinary skill in the art would have been motivated by Buchanan et al. to look for sources of butyric acid to use in the disclosed process, since this compound is described as a useful reactant. Note that while Stabel et al. describes propylene as a feedstock for the production of polypropylene, nothing about the disclosure would suggest that propylene produced by this process would necessarily have to be used for this specific purpose and could not be utilized to make other products, such as butyric acid, for which propylene is a known precursor.
Additionally, regarding the limitation requiring that the steam cracking take place in a gas furnace, Angyal et al. discloses heating the material being pyrolyzed in a controlled gas heater. (p. 1718 right column first paragraph, also figure 1)
Furthermore regarding the limitation requiring a step of feeding the recycled pyoil into the steam cracker along with a non-recycled hydrocarbon stream, into two separate coils of the gas furnace steam cracker, it would have been obvious to one of ordinary skill in the art at the time of the invention to carry out steam cracking of multiple different feedstocks, including both recycled pyoil and nonrecycled hydrocarbons such as natural gas. One of ordinary skill in the art would have found this to be obvious because both types of feedstocks are described as being useful for steam cracking to produce light olefins in the cited art, suggesting using both feedstocks as sources of light olefins (e.g. propylene) in steam cracking. In addition, Subramani et al. discloses a catalytic cracking process wherein lighter hydrocarbon feeds such as propane are processed in one reaction zone and heavier feedstocks are processed in a different reaction zone. (p. 2 paragraph 33) Propylene is listed as one of the major products of this process. (p. 5 paragraph 78) Subramani et al. further describes the cracking process as involving steam. (p. 3 paragraph 46) Therefore it would have been further obvious to carry out both steam cracking reactions (heavier pyoil and lighter propane) in the two reaction zones of a reactor according to Subramani et al. One of ordinary skill in the art would have seen the disclosures of Stabel and Akah as suggesting that both of these feedstocks as being useful for producing propylene by steam cracking, suggesting that propylene could be manufactured from both of these sources and providing a motivation to vary out both of these steam cracking processes. Subramani et al. would further have suggested that a single apparatus having multiple reactors could have been capable of carrying out these steam cracking reactions.
Regarding the limitation that the coils in the cracker be tubular coils, both Angyal (p. 1718 section 2.2.1) and Stabel et al. (column 4 lines 19-20) disclose using tubular reactors. Regarding the limitation that the r-pyoil is present in the r-pyoil is present in an amount of 8-20% of the total combined weight of the feedstocks, it is notes that both the claimed process and the prior art describe the r-pyoil and nonrecycle hydrocarbon streams as separate streams fed into separate sections of the reactor and each cracked individually. Therefore the two feedstocks are not mixed or cracked together, and the relative amount of one feedstock being fed into one zone of the reactor does not affect the cracking of the other feedstock in the other zone. As a result it would have been obvious to one of ordinary skill in the art at the time of the invention to simply use whatever amount of each feedstock is available in each reactor zone, with no expectation that the ratio of the two would be critical.
Regarding the limitation that the steam-to-hydrocarbon ratio is between 0.35:1 and 0.55:1, Gal et al. discloses a study of operating parameters of tubular furnaces used for cracking of recycled hydrocarbons. (p. 219 left column first paragraph) The reactor being testes is a steam cracker. (p. 220 right column fifth paragraph) Steam to hydrocarbon ratio is described as a result-effective variable, with lower values leading to coke formation and reduced product yield, and higher values increasing operational cost due to energy consumption. (p. 222 section 4.2) The values found to be feasible included an upper limit of about 0.5:1 and a lower limit of about 10-20% below that, or about 0.4-0.45:1. Therefore it would have been obvious to one of ordinary skill in the art at the time of the invention to optimize the steam ratio in Stabel’s steam cracking process based on the parameters described by Gal et al., as one of ordinary skill in the art would have seen this as a result effective variable for improving the operation of a steam cracking furnace.
Regarding claim 58, as mentioned previously, Buchanan et al. specifically describes making cellulose acetate butyrate. Regarding claims 59 and 61, one of ordinary skill in the art would have found it to be obvious to use natural gas comprising for example propane as part of the feedstock, in view of the disclosure by Akah et al. that these gasses are a typical feedstock for production of propylene.
Regarding claim 60, it would furthermore have been obvious to one of ordinary skill in the art at the time of the invention to determine the appropriate amount of each feedstock to use in the steam cracking process, based on factors such as their relative cost and availability, and the desired product distribution.
Regarding claim 63, while Stabel does not specifically describe the cracking temperature, Subramani describes cracking at abroad range of 450-700 degrees C. (p. 3 paragraph 46) furthermore
Therefore the invention taken as a whole is prima facie obvious.
Response to Arguments
Applicant’s arguments, submitted May 26, 2026, with respect to the above grounds of rejection, have been fully considered and not found to be persuasive to remove the rejections. Applicant argues that the cited references do not disclose all of the elements of the present claims. In particular, Applicant points to the fact that Subramani et al. describes a reactor that is not a steam cracking reactor. To support this argument, Applicant states that the steam is used only to strip hydrocarbons from the spent catalyst. Firstly, it is noted that while Subramani describes using steam for stripping spent catalyst, (p. 1 paragraph 9) steam is also present during the reaction itself. (p. 1 paragraphs 5-7) Furthermore, in the rejection as it stands, Subramani is relied upon not for the disclosure of steam cracking, but merely for teaching the concept that different feedstocks can be processed separately in different zones of the same reactor, rather than being mixed together and processed in a single coil. Even if the specifics of the reactors used by Subramani differ from those described by Stabel and Angyal, for example, the general concept that a reactor can have different zones used for processing different feedstocks would be expected by one of ordinary skill in the art to be applicable to a variety of different reactor types.
Regarding the newly introduced limitations specifying the relative amounts of recycle and nonrecycle hydrocarbons, and the steam-to-hydrocarbon ratio, Applicant argues that one of ordinary skill in the art would not have arrived at these values. However, as discussed in the presently pending rejection, Gal discloses that the steam to hydrocarbon ratio is a result effective variable and that the preferred range would be likely to fall within the scope of the claimed range.
While the prior art does not disclose any particular guidance as to the relative amounts of the recycle and nonrecycle hydrocarbons used in the process, it is important to note, that while the entirety of the method is technically described by a single claim, it is not actually a single process. Rather the claim involves performing two separate processes at once. One process involves pyrolyzing plastic waste and then steam cracking the resulting pyrolysis oil to produce propylene, while the other involves steam cracking some other hydrocarbon not derived from recycled plastic to produce propylene. While the process then involves combining the two portions of propylene, converting the propylene to butyric anhydride, and using the butyric anhydride to acylate cellulose, these are normal, routine, conventional steps that are clearly obvious over the cited art. None of Applicant’s arguments would dispute the assertion that, given a source of propylene, it would be obvious to use it as a feedstock for an acylating agent to ultimately produce cellulose butyrate.
Since the recycle content and nonrecycle content are two separate streams treated in two separate coils of the reactor, they have nothing to do with one another until the cracking process is finished and the (substantially identical) propylene products are combined. Therefore the relative amounts of the two feedstocks would be decided by other factors, such as the availability of each feedstock, and not any particular property of the two reactions run in parallel. Therefore it would have been obvious to determine the appropriate amounts of each feedstock based on extrinsic factors such as the relative availability and cost of each feedstock.
More generally, Applicant points to the number of references cited and argues that this is indicative of hindsight reconstruction. However, this is a mischaracterization of patent law. According to MPEP 2145(V), “Reliance on a large number of references in a rejection does not, without more, weigh against the obviousness of the claimed invention.” In the present case, claim 2 as it is currently pending has been assembled from a large number of elements already known in the art.(“e.g. two separate and unrelated methods for making propylene, the concept of including multiple reaction zones in a single reactor, chemical conversion of propylene into butanoic acid, and chemical acylation or cellulose. One cannot produce a patentable claim by simply stringing together enough known inventions in a more or less predictable manner to produce a claim that cannot be rejected without citing a large number of references, and then arguing that the number of references needed invalidates the rejection.
Regarding the disclosure of Subramani, Applicant argues that Subramani describes a fluid catalytic cracking apparatus that is fundamentally different from the steam cracking apparatus described by Stabel, Akah, and Angyal. Subramani’s apparatus could therefore not reasonably be combined with existing steam cracking apparatuses. While this is true of the disclosure of Subramani as a whole, the element cited in the rejection of claim 2 is simply the fact that Subramani et al. describes a reactor having two different reaction chambers designed to process two different product streams, rather than a single chamber in which all product streams are combined. This element of Subramani’s reactor design is not dependent on the specifics of the FCC process as described by Applicant. One of ordinary skill in the art could take the insight that a reactor can have multiple reaction zones to accommodate multiple feedstock streams and apply it to any reactor that would reasonably be expected to handle multiple different product streams. In this case, the fact that steam cracking is known to be used to treat both recycled pyrolysis oil and nonrecycle light hydrocarbons in order to produce propylene is an analogous situation that would call for a similar solution, such as a steam cracking apparatus having separate reaction zones for cracking pyrolysis oil and light nonrecycle hydrocarbons. Implementing this feature would not necessitate changing the entire design of the reactor to carry out FCC instead of steam cracking.
For all of these reasons the rejection is deemed proper and maintained.
Conclusion
No claims are allowed in this action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to ANDREA OLSON whose telephone number is (571)272-9051. The examiner can normally be reached M-F 6am-3:00pm.
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/ANDREA OLSON/ Primary Examiner, Art Unit 1693 7/9/2026
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