DETAILED ACTION
STATUS OF THE APPLICATION
Receipt is acknowledged of Applicants’ Amendments and Remarks, filed 12 December 2025, in the matter of Application No. 17/946,785. Said documents have been entered on the record. The Examiner further acknowledges the following:
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Claims 54-63, 65-67, and 69-75 are pending.
Claim 54 has been amended.
Claim 75 has been newly added.
No claims have been cancelled.
Thus, claims 54-63, 65-67, and 69-75 represent all claims currently under consideration.
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and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114.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 12 December 2025 has been entered.
Information Disclosure Statement
The information disclosure statements submitted on 12 December 2025 and 2 March 2026 are in compliance with the provisions of 37 CFR 1.97. Accordingly, said documents are being considered by the Examiner.
REJECTIONS-MAINTAINED, MODIFIED, & NEW
The below rejections are modified in view of the amendments to the claims. Modifications are bolded below.
MAINTAINED, MODIFIED, & NEW Claim Rejections - 35 USC § 103 – Necessitated by Amendment
In the recent response filed 12 December 2025, Applicant’s amendment to claim 54 narrowed the previously claimed temperature range of the aging method step to 200 ºC or more to 300 ºC or less. In addition, Applicant introduced newly added independent claim 75 that incorporates every feature of previous claim 54, and further incorporates the limitation wherein the regenerated composition in a liquid medium comprises acetic acid. As a result of these claim amendments, the previous 103 rejections of claims 54-55, 60-63, 65, and 69-74 were maintained and modified using the previously cited prior art as necessitated by amendment and detailed herein. Furthermore, the previously cited prior art of Biermann et al., List et al., Myerson et al., and Wang et al. were applied to and resulted in a new 103 rejection of claim 75, as detailed herein. The previously issued claim rejections can be found on pages 3-11 of the previous Office Action mailed 12 September 2025.
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.
Claims 54-55, 60-63, 65, and 69-75 are rejected under 35 U.S.C. 103 as being unpatentable over Biermann et al. (WO 2021/121731 A1; PTO-892 of 07-24-2024; English language machine translation; hereinafter “Biermann”), in view of List et al. (U.S. Patent No. 4,340,752; IDS of 09-22-2023; hereinafter “List”), Myerson et al. (Ind. Eng. Chem. Res. 1990, 29, 2089–2093; PTO-892 of 07-24-2024; hereinafter “Myerson”), and Wang et al. (Ind. Eng. Chem. Res. 2007, 46, 7367–7377; PTO-892 of 05-21-2025; hereinafter “Wang”).
Regarding claims 54 and 75, Biermann teaches a method and a device for reprocessing waste containing mainly polyalkylene terephthalate, including polyethylene terephthalate, via a continuous depolymerization process, resulting in a reaction output consisting of disodium terephthalate and monoethylene glycol, other polymers and/or mixtures of other polymers, and/or natural substances, and/or metals (Biermann; claim 1; paragraph [0027], lines 223–227; paragraph [0031], lines 259–261; paragraph [0092], lines 831–833; English language machine translation). The described depolymerization process is also characterized by the separation of the alkylene glycol from the remaining components in a liquid medium by means of distillation (Biermann; claims 3 and 11; paragraph [0098], lines 874–875; English language machine translation). Furthermore, insoluble residues (e.g., metals and remnants of other polymers) are separated by filtration, and the terephthalic acid is purified by precipitation with sulfuric acid, washed with water, and dried (Biermann; paragraph [0119], lines 1065–1070; English language machine translation).
Biermann fails to teach (1) aging the pre-aged mixture, wherein aging comprises subjecting the pre-aged mixture to thermal cycling wherein the cycling occurs within 25 ºC and within a temperature range of from 200 ºC or more to 300 ºC or less (as recited in instant claim 54) or within a temperature range of from 150 ºC or more to 300 ºC or less (as recited in instant claim 75) to form an aged mixture; (2) separating the regenerated composition from the liquid medium in the aged mixture, wherein the regenerated diacid in the regenerated composition after aging has an average crystal size of 50 microns or more as a result of aging (as recited in instant claims 54 and 75); and (3) wherein the regenerated composition in a pre-aged mixture comprises acetic acid (as recited in instant claim 75).
Regarding points (1) and (3), List (cited in applicant’s IDS) teaches a process for the purification of crude terephthalic acid that utilizes a continuous circulation (between 5 and 100 cycles) of the crude diacid through a heater (temperature range of 195–210 ºC) and a cooler (temperature range of 180–195 ºC) that allows for control of particle size of the diacid (List; claim 6; Col. 3, lines 12–21 and Col. 3, lines 23–28). The temperature ranges recited by List overlap with the range recited in instant claim 75. Furthermore, List teaches teaches that the temperature range of the dispersion in the cycle is about 180-210 ºC List; claim 3). MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.” In addition, the skilled artisan could arrive at a range of, for example, 195 ºC to 210 ºC based on the disclosed ranges of List, and this range resides close to the range recited in instant claim 54. MPEP § 2144.05(I) states that “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close.” List further teaches that the TPA is purified in the disperse form, and suitable liquid dispersants are all liquids wherein TPA is soluble in marked quantities at an elevated temperature, particularly lower carboxylic acids, but above all acetic acid that can contain up to 10% water (List; Col. 5, lines 3-8).
Further regarding points (1) and (3), Myerson defines thermal cycling as aging of the crude terephthalic acid mixture that plays a crucial role in its optimal purification and it has been shown that crystal aging is a viable and predictable method for purifying TPA (Myerson; page 2091, final paragraph and page 2092, final paragraph). It was also found that purification occurs more rapidly in 90% acetic acid than in water at the same aging conditions (Myerson; Abstract). Myerson further teaches that rapid temperature oscillations with a large amplitude (but not so large as to cause nucleation of amorphous crystal growth) will result in the largest amount of purification, and Myerson teaches several TPA purification examples in acetic acid with about 1 ºC or less temperature oscillations (Myerson; page 2092; Col. 2, paragraph 1 and Figs. 6-11). In addition, studies demonstrated that amorphous, globular TPA particles will transform into needles when suspended in their own saturated solution at temperatures ranging from 353 to 493 K (Myerson; page 2089, Col. 1, paragraph 3). Finally, Wang teaches that aging of TPA crystals in their own saturated acetic acid solution at high temperatures (467, 477, 487, 497, and 507 K) is an effective and convenient way to increase the crystal size and decrease the impurity content (Wang; page 7375; Col. 2, paragraph 6, ‘Conclusions’). The temperature range of Myerson corresponds to 80 ºC to 220 ºC, and the temperature range of Wang corresponds to 194 ºC to 234 ºC, and these ranges overlap with the ranges disclosed by List and the ranges recited in instant claims 54 and 75. MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
Thus, the combined teachings of List, Myerson, and Wang would inform the skilled artisan of the utility of aging TPA crystals in acetic acid and would serve as motivation to incorporate these concepts to the method of Biermann.
Regarding point (2), although List fails to expressly teach that the regenerated diacid in the aged mixture has an average crystal size of 50 microns or more as a result of the aging, List does teach that the average diameter of the terephthalic acid particles in the crude dispersion starting material is about 10 to 150 microns while the terephthalic acid particles in the treated dispersion are about 5 to 50 microns (List; Col. 3, lines 24-28). List further teaches that these numerical values can be exceeded either in the upper or lower directions, if the crystallizing effect, due to the choice of the temperature difference, the residence times, and/or the degree of dilution of the dispersion in the cycle by recycling the solvent from the evaporative crystallization, is especially high or particularly low; the desired efficiency is dependent on the degree of contamination and on the initial particle size of the crude terephthalic acid, and on the effect intended (List; Col. 6, lines 51-61). Thus, the collective teachings of List suggest that the average crystal size can be fine-tuned as a result of the aging process. This premise is further validated by Myerson and Wang. Myerson teaches the crystal growth and dissolution kinetics of TPA that suggest to the skilled artisan that the crystal size of TPA during thermal cycling in acetic acid is a well understood process that can be predictably controlled (Myerson; page 2089, Col. 2, paragraph 2; page 2090; Table 1). Wang teaches the aging of crude terephthalic acid crystals at high temperatures, and explicitly teaches that the crystal size distribution is observed to broaden with time, accompanied by a decrease in number and an increase in averaged crystal size during aging, during which substantial purification occurs (Wang; Title; Abstract). Therefore, the skilled artisan could reasonably arrive at the claimed particle size range of 50 microns or more by applying the teachings of List, Myerson, and Wang and through routine optimization of the parameters described above. MPEP § 2144.05(II) states that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”
Biermann, List, Myerson, and Wang are considered to be analogous to the claimed invention because they are in the same field of endeavor terephthalic acid purification, and furthermore Myerson and Wang teach the aging of crude terephthalic acid. Furthermore, the prior art as taught by List, Myerson, and Wang teach the benefits of thermal cycling via crystal aging and its predictable utility for controlling crystal size and purity, and is therefore reasonably pertinent to the problem faced by the inventor. Thus, the cited prior art is deemed analogous art, as described in MPEP § 2141.01(a). As such, the skilled artisan would have been sufficiently motivated to incorporate the teachings of List, Myerson, and Wang into the method of Biermann to pursue an improved method for terephthalic acid purification with a reasonable expectation of success. Such an endeavor would result in combining prior art elements according to known methods to yield predictable results, as described in MPEP § 2143(I)(A), and applying a known technique to a known device (method, or product) ready for improvement to yield predictable results as described in MPEP § 2143(I)(D).
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of Biermann to incorporate the teachings of List, Myerson, and Wang to implement a crystal aging method step wherein the pre-aged mixture comprises acetic acid to arrive at the claimed invention. The motivation to do so would permit the skilled artisan to pursue, with a reasonable expectation of success, an improved process for the purification of terephthalic acid that permits the predictable control of crystal growth through means of routine experimentation, as described above.
Regarding claim 55, Biermann describes polyalkylene terephthalate-containing waste material consisting of bottle, film, fiber, shell, automobile interior trim, and other packaging waste (paragraph [0062], lines 571–574; English language machine translation). Furthermore, the Examiner notes that the Applicants’ definition of waste material in the instant specification (paragraph [[0013]) states that “the waste material may be in the form of a textile, a fiber, a yarn, a film, a chip, etc.”
Regarding claims 60 and 61, Biermann teaches the purification of terephthalic acid as described above, which is itself an aromatic diacid (paragraph [0031], lines 259–261; English language machine translation).
Regarding claims 62 and 63, Biermann teaches the purification of terephthalic acid as described above, wherein the separated diol is monoethylene glycol, which is itself an aliphatic diol (paragraph [0078], lines 744–746; English language machine translation).
Regarding claim 65, Biermann teaches a method for depolymerizing polyethylene terephthalate, as described above, that includes a filtration step, which is a known method of clarification (paragraph [0119], lines 1065–1066; English language machine translation).
Regarding claims 69 and 70, Biermann teaches a depolymerization process characterized by the separation of the alkylene glycol (i.e., monoethylene glycol, MEG; a diol compound) from the remaining components in a liquid medium by means of distillation, a process that comprises isolating the regenerated diol from terephthalate and insoluble residues, including metals (Biermann; paragraph [0041], lines 378-379; paragraph [0071], lines 671-671-675; paragraph [0098], lines 874–875; English language machine translation). Furthermore, Biermann teaches a method for purifying terephthalic acid by means of precipitation with sulfuric acid, a type of strong acid, as described above (paragraph [0119], lines 1067–1070; English language machine translation).
Regarding claim 71, this claim describes duplicative operations that would be prima facie obvious to one of ordinary skill in the art, as defined in MPEP § 2144.04.
Regarding claims 72 and 73, Biermann teaches a method for reprocessing polyethylene terephthalate, a type of polyester, from waste material that may include other polymers as described above, including polyamide (paragraph [0023], lines 186–187; English language machine translation).
Regarding claim 74 depending from claim 71, one of ordinary skill in the art could reasonably predict that the precipitating step of a diacid conducted at two intervals, each at a different pH (as in instant claim 71), would involve the introduction of a strong acid to encourage full protonation of the diacid, thus lowering its aqueous solubility and encouraging its precipitation; the other alternative for achieving a different pH (according to instant claim 71) would involve the introduction of base, which would further increase aqueous solubility and would also form a carboxylate salt, a species that does not pertain to the claimed invention. Due to the inherent properties pertaining to the effects of pH upon the addition of strong acid to a mixture, it would be prima facie obvious to one of ordinary skill in the art to expect that a first interval of adding a strong acid to a mixture would inherently possess a higher pH than the subsequent pH following a second interval of adding a strong acid. MPEP § 2112 states that “The inherent teaching of a prior art reference, a question of fact, arises both in the context of anticipation and obviousness.”
Claims 56 and 57 are rejected under 35 U.S.C. 103 as being unpatentable over Biermann, List, Myerson, and Wang as applied to claim 54 above, and further in view of Allen et al. (US 2015/0105532 A1; IDS of 06-12-2024; hereinafter “Allen”).
The disclosures of Biermann, List, Myerson, and Wang are relied upon as set forth above. Of particular note, Biermann teaches a method for obtaining purified terephthalic acid from polyester waste material, as described above, but fails to teach the specific composition of trace metals in the polymer waste and instead refers to residual metals more broadly. List, Myerson, and Wang do not remedy this deficiency. However, Allen (cited in applicant’s IDS) teaches a method for depolymerizing polyesters that specifies the identities of commonplace residual polymerization catalysts from the original reaction that manufactured the polyester, including metal oxides and derivatives like antimony trioxide or antimony acetate (Allen; page 7, paragraph [0088]).
Biermann, List, Myerson, Wang, and Allen are considered to be analogous to the claimed invention because they are in the same general field of polyester manufacturing, including polymerization and depolymerization. Therefore, it would have been prima facie obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Biermann, List, Myerson, and Wang to incorporate the teachings of Allen that specifies antimony acetate or antimony trioxide as common residual metal catalysts from the original reaction employed to manufacture the polyester (page 7, paragraph [0088]).
Claims 58 and 59 are rejected under 35 U.S.C. 103 as being unpatentable over Biermann, List, Myerson, and Wang as applied to claim 54 above, and further in view of Essaddam et al. (WO 2017/007965 A1; PTO-892 of 07-24-2024; hereinafter “Essaddam”).
The disclosures of Biermann, List, Myerson, and Wang are relied upon as set forth above. Of particular note, Biermann teaches a method for depolymerizing polyester waste material, as described above, but fails to teach the relative amounts of residual metals in the polymer waste. List, Myerson, and Wang do not remedy this deficiency.
However, Essaddam teaches a method for depolymerizing polyethylene terephthalate that specifies residual metal catalysts levels of 0.01 ppm to 250 ppm in the depolymerized material (Essaddam; page 20, paragraph [00110]). Furthermore, the value of 250 ppm can be converted to roughly equate to 0.03 wt. %. Therefore, Essaddam also teaches a residual metal catalyst amount in the range of 0 wt. % to 0.03 wt. %. The disclosed ranges read directly on those recited by claims 58 (i.e., claim 58: 0 ppm < x < 300 ppm; Essaddam: 0.01 ppm < x < 250 ppm) and 59 (i.e., claim 59: 0 wt. % < x < 0.05 wt. %; Essaddam: 0 wt. % < x < 0.03 wt. %). MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists. In the instant case, the ranges disclosed by Essaddam residue squarely within the recited ranges.
Biermann, List, Myerson, Wang, and Essaddam are considered to be analogous to the claimed invention because they are in the same field of polyester manufacturing, including polymerization and depolymerization. Therefore, it would have been prima facie obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Biermann, List, Myerson, and Wang to incorporate the teachings of Essaddam that specifies numerical ranges of residual metal catalyst in depolymerized polyester waste that is consistent with the claimed invention (page 20, paragraph [00110]).
Claims 66 and 67 are rejected under 35 U.S.C. 103 as being unpatentable over Biermann, List, Myerson, and Wang as applied to claim 54 above, and further in view of Parrott et al. (WO 2021/151071 A1; PTO-892 of 07-24-2024; hereinafter “Parrott”).
The disclosures of Biermann, List, Myerson, and Wang are relied upon as set forth above. Of particular note, Biermann teaches a method for obtaining purified terephthalic acid by depolymerizing polyester waste material, as described above, including methods to remove contaminants and impurities by filtration, but fails to teach a method of decolorizing (i.e., removing colored contaminants/impurities) the depolymerized mixture with a suitable agent such as activated charcoal. List, Myerson, and Wang do not remedy this deficiency.
However, Parrott teaches a method for depolymerizing waste plastic material that includes a contamination removal step involving the passage of the depolymerized mixture through filters and/or sorbents, including activated charcoal that aims to improve the overall purity of the recycled contents (Parrott; page 4, lines 23–26).
Biermann, List, Myerson, Wang, and Parrott are considered to be analogous to the claimed invention because they are in the related fields of polymer depolymerization and terephthalic acid purification. Therefore, it would have been prima facie obvious to someone of ordinary skill in the art before the effective filing date of the claimed invention to have modified Biermann, List, Myerson, and Wang to incorporate the teachings of Parrott that includes a contamination removal step by passage of the solvent containing the depolymerized mixture through filters and/or sorbents, including activated charcoal in order to improve the overall purity of the terephthalic acid (page 4, lines 23–26).
Based on the combined teachings of the references, the Examiner submits that a person of ordinary skill in the art would have had a reasonable expectation of success of arriving at the instantly claimed method. Therefore, the invention as a whole would have been prima facie obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, and absent a clear showing of evidence to the contrary.
Response to Arguments
Claim Rejections - 35 USC § 103
Applicant's arguments filed 12 December 2025, asserting that the combination of cited references fails to teach or suggest at least the elements of independent claims 54 and 75, have been fully considered but they are not persuasive.
Applicant introduces the claim limitations that are not addressed by Biermann, and argues the following:
“In fact, the Office Action concedes that Biermann fails to teach or suggest thermal cycling and average crystal size and relies on the teachings of List, Myerson, and Wang to cure some of these deficiencies.
List is allegedly directed to a process for the purification of terephthalic acid in which a dispersion of the terephthalic acid in a liquid dispersant such as acetic acid is continuously pumped through a cycle. (Abstract). The Office Action asserts that it would have been obvious to modify Biermann based on the teachings of List (and Wang as provided below) to develop a process for the purification of a diacid from polymer waste material that includes thermal cycling. (Office Action, Pages 5-6).
However, Applicant respectfully submits that the modification of Biermann based on the teachings of List would fail to teach or suggest the method of independent claim 54. In fact, Applicant respectfully submits that List essentially teaches away from independent claim 54. Furthermore, Applicant respectfully submits that a person of ordinary skill in the art would not have combined the teachings of Biermann and List as asserted in the Office Action, particularly to arrive at independent claim 75.
First, independent claim 54 requires that the aging comprises subjecting the pre-aged mixture to thermal cycling wherein the cycling occurs within 25 °C and within a temperature range of from 200 °C or more to 300 °C or less to form an aged mixture. However, Applicant respectfully submits that List teaches away from such a temperature range. In fact, List expressly states that "this method is uneconomical, because at above 200° C. the acetic acid is degraded by oxidation, on the one hand, and the installations are corroded, on the other hand." (Col. 1, lines 58-61). Because of such potential issues, List requires at least one temperature in the cooler to be about 180° to 195°C. (Col. 3, lines 18-21).
Meanwhile, the thermal cycling as presented within independent claim 54 occurs within a temperature range of from 200°C or more to 300°C or less, outside of the temperature range of List. Accordingly, Applicant respectfully submits that modifying the method of Biermann to utilize the cycling of List would fail to teach or suggest the method of at least independent claim 54. In addition, Applicant respectfully submits that a person of ordinary skill, upon reading the disclosure of List, would be led in a direction divergent from the path that was taken by the Applicant.”
This argument has been fully considered, but is not found to be persuasive. Regarding Applicant’s argument that List teaches away from the recited temperature range and citation of List (Col. 1, lines 58-61), the “uneconomical” method characterized by acetic acid oxidation and corrosion as recited by Applicant is in reference to the method of British Pat. No. 982,629, wherein TPA is subjected to a secondary oxidation step in acetic acid at 250 ºC (List; Col. 1, lines 54-61). In addition, List further teaches that the process cannot be operated usefully, though, at below 200 C, because the solubility of TPA is too low; a purified TPA is obtained in this case only if the crude TPA has already a very high degree of purity (List; Col. 1, lines 61-65). The Examiner maintains that the temperature ranges disclosed by List overlap with or are reasonably close to the ranges recited in claims 54 and 75 as to render them obvious to the skilled artisan, as detailed above in the modified and maintained claim rejections (List; claims 3 and 6; Col. 3, lines 12–21 and Col. 3, lines 23–28). Furthermore, both Myerson and Wang teach TPA purification methods in acetic acid at temperature ranges that correspond to both the method of List and the methods of instant claims 54 and 75 (Myerson; page 2089, Col. 1, paragraph 3; Wang; page 7375; Col. 2, paragraphs 6-7, ‘Conclusions’). See MPEP § 2144.05(I). Therefore, the claim rejections are maintained for the reasons of record and the reasons set forth above.
Applicant argues the following:
“Second, independent claim 74 requires that the regenerated composition is provided in a liquid medium comprising acetic acid to form a pre-aged mixture. However, nowhere does Biermann disclose the use of acetic acid. While List mentions the use of acetic acid, Applicant respectfully submits that a person of ordinary skill in the art, based on the teachings of Biermann, would not modify Biermann based on the teachings of List by utilizing acetic acid.
For instance, Biermann expressly requires that the acid utilized for precipitation of the terephthalic acid be stronger than terephthalic acid. In this regard, Biermann discloses the use of sulfuric acid but fails to mention the use of any other acid. In addition, it is our understanding that sulfuric acid has a pKa1 of approximately -3 and a pKa2 of approximately 1.99. Also, it is our understanding that terephthalic acid has a pKa1 of approximately 3.54 and a pKa2 of approximately 4.46. In this regard, it is our understanding that sulfuric acid is stronger than terephthalic acid.
Meanwhile, it is our understanding that acetic acid has a pKa of approximately 4.76. Accordingly, it is our understanding that acetic acid is not stronger than terephthalic acid.
As a result, a person of ordinary skill in the art, upon considering the disclosure of Biermann, would not utilize acetic acid as required by List for precipitating the terephthalic acid therein. Accordingly, Applicant respectfully submits that a person of ordinary skill in the art, based on the teachings of Biermann, would not modify Biermann based on the teachings of List and utilize acetic acid.
Myerson is allegedly directed to the removal of 4-carboxybenzaldehype (4-CBA) from terephthalic acid (TPA) crystals in an aqueous solution or a 90% acetic acid solution. (Abstract). The Office Action utilizes Myerson for its alleged teachings regarding the average crystal size. However, Applicant respectfully submits that Myerson fails to cure the deficiencies of Biermann noted above.
Wang is allegedly directed to aging crude terephthalic acid crystals at various temperatures and measuring the contents of the contaminant 4-carboxybenzaldehyde in the solid and liquid phases. (Abstract). The Office Action utilizes Wang for its alleged teachings regarding aging crude terephthalic acid crystals at high temperatures. However, Applicant respectfully submits that Wang fails to cure the deficiencies of Biermann noted above.”
This argument has been fully considered, but is not found to be persuasive. As detailed in the maintained and modified 103 rejections above, Biermann teaches that the terephthalic acid is purified by precipitation with sulfuric acid, washed with water, and dried (Biermann; paragraph [0119], lines 1065–1070; English language machine translation). Since Biermann fails to teach a crystal aging method step, the additional teachings of List, Myerson, and Wang are relied upon because they would inform the skilled artisan of the utility of TPA crystal aging in acetic acid for means of improving TPA purity and controlling TPA crystal size, as detailed above. The Examiner submits that Applicant erroneously conflates the precipitation method step of Biermann with the crystal gaining method step of List, Myerson, and Wang. That is, the skilled artisan would recognize that the precipitation step of Biermann and the crystal aging method step of List, Myerson, and Wang are separate method steps, such that the combination of the cited prior art includes both method steps, and one does not exclude the other. Thus, the teachings of List, Myerson, and Wang could be incorporated into the method of Biermann to permit the skilled artisan to pursue an improved TPA purification method with a reasonable expectation of success. See MPEP § 2143(I)(A) and MPEP § 2143(I)(D). Therefore, the claim rejections are maintained for the reasons of record and the reasons set forth above.
MAINTAINED, MODIFIED, & NEW Claim Rejections - Double Patenting – Necessitated by Amendment
The nonstatutory double patenting rejection is based on a judicially created doctrine grounded in public policy (a policy reflected in the statute) so as to prevent the unjustified or improper timewise extension of the “right to exclude” granted by a patent and to prevent possible harassment by multiple assignees. A nonstatutory double patenting rejection is appropriate where the conflicting claims are not identical, but at least one examined application claim is not patentably distinct from the reference claim(s) because the examined application claim is either anticipated by, or would have been obvious over, the reference claim(s). See, e.g., In re Berg, 140 F.3d 1428, 46 USPQ2d 1226 (Fed. Cir. 1998); In re Goodman, 11 F.3d 1046, 29 USPQ2d 2010 (Fed. Cir. 1993); In re Longi, 759 F.2d 887, 225 USPQ 645 (Fed. Cir. 1985); In re Van Ornum, 686 F.2d 937, 214 USPQ 761 (CCPA 1982); In re Vogel, 422 F.2d 438, 164 USPQ 619 (CCPA 1970); In re Thorington, 418 F.2d 528, 163 USPQ 644 (CCPA 1969).
A timely filed terminal disclaimer in compliance with 37 CFR 1.321(c) or 1.321(d) may be used to overcome an actual or provisional rejection based on nonstatutory double patenting provided the reference application or patent either is shown to be commonly owned with the examined application, or claims an invention made as a result of activities undertaken within the scope of a joint research agreement. See MPEP § 717.02 for applications subject to examination under the first inventor to file provisions of the AIA as explained in MPEP § 2159. See MPEP § 2146 et seq. for applications not subject to examination under the first inventor to file provisions of the AIA . A terminal disclaimer must be signed in compliance with 37 CFR 1.321(b).
The filing of a terminal disclaimer by itself is not a complete reply to a nonstatutory double patenting (NSDP) rejection. A complete reply requires that the terminal disclaimer be accompanied by a reply requesting reconsideration of the prior Office action. Even where the NSDP rejection is provisional the reply must be complete. See MPEP § 804, subsection I.B.1. For a reply to a non-final Office action, see 37 CFR 1.111(a). For a reply to final Office action, see 37 CFR 1.113(c). A request for reconsideration while not provided for in 37 CFR 1.113(c) may be filed after final for consideration. See MPEP §§ 706.07(e) and 714.13.
The USPTO Internet website contains terminal disclaimer forms which may be used. Please visit www.uspto.gov/patent/patents-forms. The actual filing date of the application in which the form is filed determines what form (e.g., PTO/SB/25, PTO/SB/26, PTO/AIA /25, or PTO/AIA /26) should be used. A web-based eTerminal Disclaimer may be filled out completely online using web-screens. An eTerminal Disclaimer that meets all requirements is auto-processed and approved immediately upon submission. For more information about eTerminal Disclaimers, refer to www.uspto.gov/patents/apply/applying-online/eterminal-disclaimer.
Claims 54-63, 65-67, and 69-75 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 47-57, 62-64, and 65-69 of copending Application No. 17/946,723 in view of List (U.S. Patent No. 4,340,752; IDS of 09-22-2023), Myerson (Ind. Eng. Chem. Res. 1990, 29, 2089–2093; PTO-892 of 07-24-2024), and Wang (Ind. Eng. Chem. Res. 2007, 46, 7367–7377; PTO-892 of 05-21-2025).
Although the claims at issue are not identical, they are not patentably distinct from each other.
Claim 47 of the copending application teaches every limitation of instant claims 54 and 75 with the exception of (1) aging the pre-aged mixture, wherein aging comprises subjecting the pre-aged mixture to thermal cycling wherein the cycling occurs within 25 ºC and within a temperature range of from 200 ºC or more to 300 ºC or less (as recited in instant claim 54) or within a temperature range of from 150 ºC or more to 300 ºC or less (as recited in instant claim 75) to form an aged mixture; (2) separating the regenerated composition from the liquid medium in the aged mixture, wherein the regenerated diacid in the regenerated composition after aging has an average crystal size of 50 microns or more as a result of aging (as recited in instant claims 54 and 75); and (3) wherein the regenerated composition in a pre-aged mixture comprises acetic acid (as recited in instant claim 75).
These deficiencies are remedied by List, Myerson, and Wang, who teach the following.
Regarding points (1) and (3), List (cited in applicant’s IDS) teaches a process for the purification of crude terephthalic acid that utilizes a continuous circulation (between 5 and 100 cycles) of the crude diacid through a heater (temperature range of 195–210 ºC) and a cooler (temperature range of 180–195 ºC) that allows for control of particle size of the diacid (List; claim 6; Col. 3, lines 12–21 and Col. 3, lines 23–28). The temperature ranges recited by List overlap with the range recited in instant claim 75. Furthermore, List teaches teaches that the temperature range of the dispersion in the cycle is about 180-210 ºC List; claim 3). MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.” In addition, the skilled artisan could arrive at a range of, for example, 195 ºC to 210 ºC based on the disclosed ranges of List, and this range resides close to the range recited in instant claim 54. MPEP § 2144.05(I) states that “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close.” List further teaches that the TPA is purified in the disperse form, and suitable liquid dispersants are all liquids wherein TPA is soluble in marked quantities at an elevated temperature, particularly lower carboxylic acids, but above all acetic acid that can contain up to 10% water (List; Col. 5, lines 3-8).
Further regarding points (1) and (3), Myerson defines thermal cycling as aging of the crude terephthalic acid mixture that plays a crucial role in its optimal purification and it has been shown that crystal aging is a viable and predictable method for purifying TPA (Myerson; page 2091, final paragraph and page 2092, final paragraph). It was also found that purification occurs more rapidly in 90% acetic acid than in water at the same aging conditions (Myerson; Abstract). Myerson further teaches that rapid temperature oscillations with a large amplitude (but not so large as to cause nucleation of amorphous crystal growth) will result in the largest amount of purification, and Myerson teaches several TPA purification examples in acetic acid with about 1 ºC or less temperature oscillations (Myerson; page 2092; Col. 2, paragraph 1 and Figs. 6-11). In addition, studies demonstrated that amorphous, globular TPA particles will transform into needles when suspended in their own saturated solution at temperatures ranging from 353 to 493 K (Myerson; page 2089, Col. 1, paragraph 3). Finally, Wang teaches that aging of TPA crystals in their own saturated acetic acid solution at high temperatures (467, 477, 487, 497, and 507 K) is an effective and convenient way to increase the crystal size and decrease the impurity content (Wang; page 7375; Col. 2, paragraph 6, ‘Conclusions’). The temperature range of Myerson corresponds to 80 ºC to 220 ºC, and the temperature range of Wang corresponds to 194 ºC to 234 ºC, and these ranges overlap with the ranges disclosed by List and the ranges recited in instant claims 54 and 75. MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
Thus, the combined teachings of List, Myerson, and Wang would inform the skilled artisan of the utility of aging TPA crystals in acetic acid and would serve as motivation to incorporate these concepts to the method of Biermann.
Regarding point (2), although List fails to expressly teach that the regenerated diacid in the aged mixture has an average crystal size of 50 microns or more as a result of the aging, List does teach that the average diameter of the terephthalic acid particles in the crude dispersion starting material is about 10 to 150 microns while the terephthalic acid particles in the treated dispersion are about 5 to 50 microns (List; Col. 3, lines 24-28). List further teaches that these numerical values can be exceeded either in the upper or lower directions, if the crystallizing effect, due to the choice of the temperature difference, the residence times, and/or the degree of dilution of the dispersion in the cycle by recycling the solvent from the evaporative crystallization, is especially high or particularly low; the desired efficiency is dependent on the degree of contamination and on the initial particle size of the crude terephthalic acid, and on the effect intended (List; Col. 6, lines 51-61). Thus, the collective teachings of List suggest that the average crystal size can be fine-tuned as a result of the aging process. This premise is further validated by Myerson and Wang. Myerson teaches the crystal growth and dissolution kinetics of TPA that suggest to the skilled artisan that the crystal size of TPA during thermal cycling in acetic acid is a well understood process that can be predictably controlled (Myerson; page 2089, Col. 2, paragraph 2; page 2090; Table 1). Wang teaches the aging of crude terephthalic acid crystals at high temperatures, and explicitly teaches that the crystal size distribution is observed to broaden with time, accompanied by a decrease in number and an increase in averaged crystal size during aging, during which substantial purification occurs (Wang; Title; Abstract). Therefore, the skilled artisan could reasonably arrive at the claimed particle size range of 50 microns or more by applying the teachings of List, Myerson, and Wang and through routine optimization of the parameters described above. MPEP § 2144.05(II) states that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”
Copending Application No. 17/946,723, List, Myerson, and Wang are considered to be analogous to the claimed invention because they are in the same field of endeavor terephthalic acid purification, and furthermore Myerson and Wang teach the aging of crude terephthalic acid. Furthermore, the prior art as taught by List, Myerson, and Wang teach the benefits of thermal cycling via crystal aging and its predictable utility for controlling crystal size and purity, and is therefore reasonably pertinent to the problem faced by the inventor. Thus, the cited prior art is deemed analogous art, as described in MPEP § 2141.01(a). As such, the skilled artisan would have been sufficiently motivated to incorporate the teachings of List, Myerson, and Wang into the method of copending Application No. 17/946,723 to pursue an improved method for terephthalic acid purification with a reasonable expectation of success. Such an endeavor would result in combining prior art elements according to known methods to yield predictable results, as described in MPEP § 2143(I)(A), and applying a known technique to a known device (method, or product) ready for improvement to yield predictable results as described in MPEP § 2143(I)(D).
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of copending Application No. 17/946,723 to incorporate the teachings of List, Myerson, and Wang to implement a crystal aging method step wherein the pre-aged mixture comprises acetic acid to arrive at the claimed invention. The motivation to do so would permit the skilled artisan to pursue, with a reasonable expectation of success, an improved process for the purification of terephthalic acid that permits the predictable control of crystal growth through means of routine experimentation, as described above.
Claims 48–49 of the copending application teaches every limitation of instant claims 55–56.
Claims 50–51 of the copending application teaches every limitation of instant claim 57.
Claims 52–57 of the copending application teaches every limitation of instant claims 58–63.
Claims 62–64 of the copending application teaches every limitation of instant claims 65–67.
Claims 47 and 65–69 of the copending application teaches every limitation of instant claims 69–73.
Regarding instant claim 74 depending from instant claim 71, claim 67 of the copending application teaches every limitation of instant claim 71, but fails to teach wherein a pH of a first interval is higher than the pH of a second interval.
However, one of ordinary skill in the art could reasonably predict that the precipitating step of a diacid conducted at two intervals, each at a different pH (as in instant claim 71), would involve the introduction of a strong acid to encourage full protonation of the diacid, thus lowering its aqueous solubility and encouraging its precipitation; the other alternative for achieving a different pH (according to instant claim 71) would involve the introduction of base, which would further increase aqueous solubility and would also form a carboxylate salt, a species that does not pertain to the claimed invention. Due to the inherent properties pertaining to the effects of pH upon the addition of strong acid to a mixture, it would be prima facie obvious to one of ordinary skill in the art to expect that a first interval of adding a strong acid to a mixture would inherently possess a higher pH than the subsequent pH following a second interval of adding a strong acid. MPEP § 2112 states that “The inherent teaching of a prior art reference, a question of fact, arises both in the context of anticipation and obviousness.”
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 54 and 69-75 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 8-9, 12, and 14-15 of copending Application No. 19/238,747 in view of List (U.S. Patent No. 4,340,752; IDS of 09-22-2023), Myerson (Ind. Eng. Chem. Res. 1990, 29, 2089–2093; PTO-892 of 07-24-2024), and Wang (Ind. Eng. Chem. Res. 2007, 46, 7367–7377; PTO-892 of 05-21-2025).
Although the claims at issue are not identical, they are not patentably distinct from each other.
Claim 1 of the copending application teaches every limitation of instant claims 54 and 75 with the exception of (1) aging the pre-aged mixture, wherein aging comprises subjecting the pre-aged mixture to thermal cycling wherein the cycling occurs within 25 ºC and within a temperature range of from 200 ºC or more to 300 ºC or less (as recited in instant claim 54) or within a temperature range of from 150 ºC or more to 300 ºC or less (as recited in instant claim 75) to form an aged mixture; (2) separating the regenerated composition from the liquid medium in the aged mixture, wherein the regenerated diacid in the regenerated composition after aging has an average crystal size of 50 microns or more as a result of aging (as recited in instant claims 54 and 75); and (3) wherein the regenerated composition in a pre-aged mixture comprises acetic acid (as recited in instant claim 75).
These deficiencies are remedied by List, Myerson, and Wang, who teach the following.
Regarding points (1) and (3), List (cited in applicant’s IDS) teaches a process for the purification of crude terephthalic acid that utilizes a continuous circulation (between 5 and 100 cycles) of the crude diacid through a heater (temperature range of 195–210 ºC) and a cooler (temperature range of 180–195 ºC) that allows for control of particle size of the diacid (List; claim 6; Col. 3, lines 12–21 and Col. 3, lines 23–28). The temperature ranges recited by List overlap with the range recited in instant claim 75. Furthermore, List teaches teaches that the temperature range of the dispersion in the cycle is about 180-210 ºC List; claim 3). MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.” In addition, the skilled artisan could arrive at a range of, for example, 195 ºC to 210 ºC based on the disclosed ranges of List, and this range resides close to the range recited in instant claim 54. MPEP § 2144.05(I) states that “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close.” List further teaches that the TPA is purified in the disperse form, and suitable liquid dispersants are all liquids wherein TPA is soluble in marked quantities at an elevated temperature, particularly lower carboxylic acids, but above all acetic acid that can contain up to 10% water (List; Col. 5, lines 3-8).
Further regarding points (1) and (3), Myerson defines thermal cycling as aging of the crude terephthalic acid mixture that plays a crucial role in its optimal purification and it has been shown that crystal aging is a viable and predictable method for purifying TPA (Myerson; page 2091, final paragraph and page 2092, final paragraph). It was also found that purification occurs more rapidly in 90% acetic acid than in water at the same aging conditions (Myerson; Abstract). Myerson further teaches that rapid temperature oscillations with a large amplitude (but not so large as to cause nucleation of amorphous crystal growth) will result in the largest amount of purification, and Myerson teaches several TPA purification examples in acetic acid with about 1 ºC or less temperature oscillations (Myerson; page 2092; Col. 2, paragraph 1 and Figs. 6-11). In addition, studies demonstrated that amorphous, globular TPA particles will transform into needles when suspended in their own saturated solution at temperatures ranging from 353 to 493 K (Myerson; page 2089, Col. 1, paragraph 3). Finally, Wang teaches that aging of TPA crystals in their own saturated acetic acid solution at high temperatures (467, 477, 487, 497, and 507 K) is an effective and convenient way to increase the crystal size and decrease the impurity content (Wang; page 7375; Col. 2, paragraph 6, ‘Conclusions’). The temperature range of Myerson corresponds to 80 ºC to 220 ºC, and the temperature range of Wang corresponds to 194 ºC to 234 ºC, and these ranges overlap with the ranges disclosed by List and the ranges recited in instant claims 54 and 75. MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
Thus, the combined teachings of List, Myerson, and Wang would inform the skilled artisan of the utility of aging TPA crystals in acetic acid and would serve as motivation to incorporate these concepts to the method of Biermann.
Regarding point (2), although List fails to expressly teach that the regenerated diacid in the aged mixture has an average crystal size of 50 microns or more as a result of the aging, List does teach that the average diameter of the terephthalic acid particles in the crude dispersion starting material is about 10 to 150 microns while the terephthalic acid particles in the treated dispersion are about 5 to 50 microns (List; Col. 3, lines 24-28). List further teaches that these numerical values can be exceeded either in the upper or lower directions, if the crystallizing effect, due to the choice of the temperature difference, the residence times, and/or the degree of dilution of the dispersion in the cycle by recycling the solvent from the evaporative crystallization, is especially high or particularly low; the desired efficiency is dependent on the degree of contamination and on the initial particle size of the crude terephthalic acid, and on the effect intended (List; Col. 6, lines 51-61). Thus, the collective teachings of List suggest that the average crystal size can be fine-tuned as a result of the aging process. This premise is further validated by Myerson and Wang. Myerson teaches the crystal growth and dissolution kinetics of TPA that suggest to the skilled artisan that the crystal size of TPA during thermal cycling in acetic acid is a well understood process that can be predictably controlled (Myerson; page 2089, Col. 2, paragraph 2; page 2090; Table 1). Wang teaches the aging of crude terephthalic acid crystals at high temperatures, and explicitly teaches that the crystal size distribution is observed to broaden with time, accompanied by a decrease in number and an increase in averaged crystal size during aging, during which substantial purification occurs (Wang; Title; Abstract). Therefore, the skilled artisan could reasonably arrive at the claimed particle size range of 50 microns or more by applying the teachings of List, Myerson, and Wang and through routine optimization of the parameters described above. MPEP § 2144.05(II) states that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”
Copending Application No. 19/238,747, List, Myerson, and Wang are considered to be analogous to the claimed invention because they are in the same field of endeavor terephthalic acid purification, and furthermore Myerson and Wang teach the aging of crude terephthalic acid. Furthermore, the prior art as taught by List, Myerson, and Wang teach the benefits of thermal cycling via crystal aging and its predictable utility for controlling crystal size and purity, and is therefore reasonably pertinent to the problem faced by the inventor. Thus, the cited prior art is deemed analogous art, as described in MPEP § 2141.01(a). As such, the skilled artisan would have been sufficiently motivated to incorporate the teachings of List, Myerson, and Wang into the method of copending Application No. 17/946,723 to pursue an improved method for terephthalic acid purification with a reasonable expectation of success. Such an endeavor would result in combining prior art elements according to known methods to yield predictable results, as described in MPEP § 2143(I)(A), and applying a known technique to a known device (method, or product) ready for improvement to yield predictable results as described in MPEP § 2143(I)(D).
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of copending Application No. 19/238,747 to incorporate the teachings of List, Myerson, and Wang to implement a crystal aging method step wherein the pre-aged mixture comprises acetic acid to arrive at the claimed invention. The motivation to do so would permit the skilled artisan to pursue, with a reasonable expectation of success, an improved process for the purification of terephthalic acid that permits the predictable control of crystal growth through means of routine experimentation, as described above.
Claims 1 and 8 of the copending application teaches every limitation of instant claim 69.
Claim 9 of the copending application teaches every limitation of instant claim 70.
Claim 12 of the copending application teaches every limitation of instant claim 71.
Claims 14-15 of the copending application teaches every limitation of instant claims 72-73.
Regarding instant claim 74 depending from instant claim 71, claim 12 of the copending application teaches every limitation of instant claim 71, but fails to teach wherein a pH of a first interval is higher than the pH of a second interval.
However, one of ordinary skill in the art could reasonably predict that the precipitating step of a diacid conducted at two intervals, each at a different pH (as in instant claim 71), would involve the introduction of a strong acid to encourage full protonation of the diacid, thus lowering its aqueous solubility and encouraging its precipitation; the other alternative for achieving a different pH (according to instant claim 71) would involve the introduction of base, which would further increase aqueous solubility and would also form a carboxylate salt, a species that does not pertain to the claimed invention. Due to the inherent properties pertaining to the effects of pH upon the addition of strong acid to a mixture, it would be prima facie obvious to one of ordinary skill in the art to expect that a first interval of adding a strong acid to a mixture would inherently possess a higher pH than the subsequent pH following a second interval of adding a strong acid. MPEP § 2112 states that “The inherent teaching of a prior art reference, a question of fact, arises both in the context of anticipation and obviousness.”
This is a provisional nonstatutory double patenting rejection because the patentably indistinct claims have not in fact been patented.
Claims 54-63 and 69-75 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-4, 7-8, 10-13, and 16-21 of U.S. Patent No. 12,331,157 B2 in view of List (U.S. Patent No. 4,340,752; IDS of 09-22-2023), Myerson (Ind. Eng. Chem. Res. 1990, 29, 2089–2093; PTO-892 of 07-24-2024), and Wang (Ind. Eng. Chem. Res. 2007, 46, 7367–7377; PTO-892 of 05-21-2025).
Although the claims at issue are not identical, they are not patentably distinct from each other.
Claims 1 and 16 of U.S. Patent No. 12,331,157 B2 teaches every limitation of instant claims 54 and 75 with the exception of (1) aging the pre-aged mixture, wherein aging comprises subjecting the pre-aged mixture to thermal cycling wherein the cycling occurs within 25 ºC and within a temperature range of from 200 ºC or more to 300 ºC or less (as recited in instant claim 54) or within a temperature range of from 150 ºC or more to 300 ºC or less (as recited in instant claim 75) to form an aged mixture; (2) separating the regenerated composition from the liquid medium in the aged mixture, wherein the regenerated diacid in the regenerated composition after aging has an average crystal size of 50 microns or more as a result of aging (as recited in instant claims 54 and 75); and (3) wherein the regenerated composition in a pre-aged mixture comprises acetic acid (as recited in instant claim 75).
These deficiencies are remedied by List, Myerson, and Wang, who teach the following.
Regarding points (1) and (3), List (cited in applicant’s IDS) teaches a process for the purification of crude terephthalic acid that utilizes a continuous circulation (between 5 and 100 cycles) of the crude diacid through a heater (temperature range of 195–210 ºC) and a cooler (temperature range of 180–195 ºC) that allows for control of particle size of the diacid (List; claim 6; Col. 3, lines 12–21 and Col. 3, lines 23–28). The temperature ranges recited by List overlap with the range recited in instant claim 75. Furthermore, List teaches teaches that the temperature range of the dispersion in the cycle is about 180-210 ºC List; claim 3). MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.” In addition, the skilled artisan could arrive at a range of, for example, 195 ºC to 210 ºC based on the disclosed ranges of List, and this range resides close to the range recited in instant claim 54. MPEP § 2144.05(I) states that “a prima facie case of obviousness exists where the claimed ranges or amounts do not overlap with the prior art but are merely close.” List further teaches that the TPA is purified in the disperse form, and suitable liquid dispersants are all liquids wherein TPA is soluble in marked quantities at an elevated temperature, particularly lower carboxylic acids, but above all acetic acid that can contain up to 10% water (List; Col. 5, lines 3-8).
Further regarding points (1) and (3), Myerson defines thermal cycling as aging of the crude terephthalic acid mixture that plays a crucial role in its optimal purification and it has been shown that crystal aging is a viable and predictable method for purifying TPA (Myerson; page 2091, final paragraph and page 2092, final paragraph). It was also found that purification occurs more rapidly in 90% acetic acid than in water at the same aging conditions (Myerson; Abstract). Myerson further teaches that rapid temperature oscillations with a large amplitude (but not so large as to cause nucleation of amorphous crystal growth) will result in the largest amount of purification, and Myerson teaches several TPA purification examples in acetic acid with about 1 ºC or less temperature oscillations (Myerson; page 2092; Col. 2, paragraph 1 and Figs. 6-11). In addition, studies demonstrated that amorphous, globular TPA particles will transform into needles when suspended in their own saturated solution at temperatures ranging from 353 to 493 K (Myerson; page 2089, Col. 1, paragraph 3). Finally, Wang teaches that aging of TPA crystals in their own saturated acetic acid solution at high temperatures (467, 477, 487, 497, and 507 K) is an effective and convenient way to increase the crystal size and decrease the impurity content (Wang; page 7375; Col. 2, paragraph 6, ‘Conclusions’). The temperature range of Myerson corresponds to 80 ºC to 220 ºC, and the temperature range of Wang corresponds to 194 ºC to 234 ºC, and these ranges overlap with the ranges disclosed by List and the ranges recited in instant claims 54 and 75. MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
Thus, the combined teachings of List, Myerson, and Wang would inform the skilled artisan of the utility of aging TPA crystals in acetic acid and would serve as motivation to incorporate these concepts to the method of Biermann.
Regarding point (2), although List fails to expressly teach that the regenerated diacid in the aged mixture has an average crystal size of 50 microns or more as a result of the aging, List does teach that the average diameter of the terephthalic acid particles in the crude dispersion starting material is about 10 to 150 microns while the terephthalic acid particles in the treated dispersion are about 5 to 50 microns (List; Col. 3, lines 24-28). List further teaches that these numerical values can be exceeded either in the upper or lower directions, if the crystallizing effect, due to the choice of the temperature difference, the residence times, and/or the degree of dilution of the dispersion in the cycle by recycling the solvent from the evaporative crystallization, is especially high or particularly low; the desired efficiency is dependent on the degree of contamination and on the initial particle size of the crude terephthalic acid, and on the effect intended (List; Col. 6, lines 51-61). Thus, the collective teachings of List suggest that the average crystal size can be fine-tuned as a result of the aging process. This premise is further validated by Myerson and Wang. Myerson teaches the crystal growth and dissolution kinetics of TPA that suggest to the skilled artisan that the crystal size of TPA during thermal cycling in acetic acid is a well understood process that can be predictably controlled (Myerson; page 2089, Col. 2, paragraph 2; page 2090; Table 1). Wang teaches the aging of crude terephthalic acid crystals at high temperatures, and explicitly teaches that the crystal size distribution is observed to broaden with time, accompanied by a decrease in number and an increase in averaged crystal size during aging, during which substantial purification occurs (Wang; Title; Abstract). Therefore, the skilled artisan could reasonably arrive at the claimed particle size range of 50 microns or more by applying the teachings of List, Myerson, and Wang and through routine optimization of the parameters described above. MPEP § 2144.05(II) states that “[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation.”
U.S. Patent No. 12,331,157 B2, List, Myerson, and Wang are considered to be analogous to the claimed invention because they are in the same field of endeavor terephthalic acid purification, and furthermore Myerson and Wang teach the aging of crude terephthalic acid. Furthermore, the prior art as taught by List, Myerson, and Wang teach the benefits of thermal cycling via crystal aging and its predictable utility for controlling crystal size and purity, and is therefore reasonably pertinent to the problem faced by the inventor. Thus, the cited prior art is deemed analogous art, as described in MPEP § 2141.01(a). As such, the skilled artisan would have been sufficiently motivated to incorporate the teachings of List, Myerson, and Wang into the method of U.S. Patent No. 12,331,157 B2 to pursue an improved method for terephthalic acid purification with a reasonable expectation of success. Such an endeavor would result in combining prior art elements according to known methods to yield predictable results, as described in MPEP § 2143(I)(A), and applying a known technique to a known device (method, or product) ready for improvement to yield predictable results as described in MPEP § 2143(I)(D).
Therefore, it would have been prima facie obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to have modified the method of U.S. Patent No. 12,331,157 B2 to incorporate the teachings of List, Myerson, and Wang to implement a crystal aging method step wherein the pre-aged mixture comprises acetic acid to arrive at the claimed invention. The motivation to do so would permit the skilled artisan to pursue, with a reasonable expectation of success, an improved process for the purification of terephthalic acid that permits the predictable control of crystal growth through means of routine experimentation, as described above.
Claim 15 of U.S. Patent No. 12,331,157 B2 teaches every limitation of instant claim 55.
Claims 2-3 of U.S. Patent No. 12,331,157 B2 teach every limitation of instant claim 56.
Claim 4 of U.S. Patent No. 12,331,157 B2 teaches every limitation of instant claim 57.
Regarding instant claim 58, Claim 7 of U.S. Patent No. 12,331,157 B2 teaches wherein the catalyst is present in the regenerated composition in an amount of from greater than 10 ppm to 300 ppm. This range overlaps significantly with the range recited in the instant claim. MPEP § 2144.05(I) states that “[i]n the case where the claimed ranges ‘overlap or lie inside ranges disclosed by the prior art’ a prima facie case of obviousness exists.”
Claim 8 of U.S. Patent No. 12,331,157 B2 teaches every limitation of instant claim 59.
Claims 10-13 of U.S. Patent No. 12,331,157 B2 teach every limitation of instant claims 60-63.
Claims 1 and 16-17 of U.S. Patent No. 12,331,157 B2 teach every limitation of instant claim 69.
Claims 18-21 of U.S. Patent No. 12,331,157 B2 teach every limitation of instant claims 70-73.
Regarding instant claim 74 depending from instant claim 71, claim 19 of U.S. Patent No. 12,331,157 B2 teaches every limitation of instant claim 71, but fails to teach wherein a pH of a first interval is higher than the pH of a second interval.
However, one of ordinary skill in the art could reasonably predict that the precipitating step of a diacid conducted at two intervals, each at a different pH (as in instant claim 71), would involve the introduction of a strong acid to encourage full protonation of the diacid, thus lowering its aqueous solubility and encouraging its precipitation; the other alternative for achieving a different pH (according to instant claim 71) would involve the introduction of base, which would further increase aqueous solubility and would also form a carboxylate salt, a species that does not pertain to the claimed invention. Due to the inherent properties pertaining to the effects of pH upon the addition of strong acid to a mixture, it would be prima facie obvious to one of ordinary skill in the art to expect that a first interval of adding a strong acid to a mixture would inherently possess a higher pH than the subsequent pH following a second interval of adding a strong acid. MPEP § 2112 states that “The inherent teaching of a prior art reference, a question of fact, arises both in the context of anticipation and obviousness.”
Response to Arguments
Claim Rejections – Double Patenting
Applicant's remarks filed 12 December 2025, stating that Applicant will submit a terminal disclaimer, if in fact necessary, to overcome the rejection at such time that the pending claims are otherwise found in condition for allowance, is acknowledged. In view of the maintained, modified, and new 103 rejections described herein, the provisional nonstatutory double patenting rejections of claims 54-63, 65-67, and 69-75 over claims 47-57, 62-64, and 65-69 of copending U.S. Application No. 17/946,723 are hereby maintained.
Furthermore, as a result of a new search necessitated by Applicant’s amendments, new double patenting rejections have been applied, wherein claims 54 and 69-75 are provisionally rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1, 8-9, 12, and 14-15 of copending Application No. 19/238,747 in view of List, Myerson, and Wang, and claims 54-63 and 69-75 are rejected on the ground of nonstatutory double patenting as being unpatentable over claims 1-4, 7-8, 10-13, and 16-21 of U.S. Patent No. 12,331,157 B2 in view of List, Myerson, and Wang, as detailed above.
The Examiner notes that filing a terminal disclaimer will ameliorate these double patenting rejections.
Conclusion
Any inquiry concerning this communication or earlier communications from the Examiner should be directed to Derek Rhoades whose telephone number is (703)-756-5321. The Examiner can normally be reached Monday–Thursday, 7:30 am–5:00 pm EST; Friday, 7:30 am–4:00 pm EST.
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/D.R./Examiner, Art Unit 1692
/AMY C BONAPARTE/Primary Examiner, Art Unit 1692