DETAILED ACTION
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.
No claims have been amended.
No claims have been cancelled.
Thus, claims 54-63, 65-67, and 69-75 represent all claims currently under consideration.
MAINTAINED 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 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 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
Applicant's arguments filed 6/18/2026, asserting that the combination of cited references fails to teach or suggest at least the elements of independent claim 54, a method of obtaining a purified regenerated diacid from a depolymerization of a polyester, wherein the method includes aging a pre-aged mixture via 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 to form an aged mixture, and independent claim 75, a method incorporating the elements of claim 54 with the further limitation of a liquid medium comprising acetic acid, have been fully considered but they are not persuasive.
Applicant argues the following:
“In particular, Applicant respectfully submits that the proposed combination lacks a rational basis under 35 U.S.C. § 103 because it seeks to combine secondary references that are in direct, irreconcilable scientific conflict regarding the fundamental physics of high-temperature crystal growth. For instance, the Office Action relies on Myerson to establish the predictable utility of thermal cycling, noting that rapid temperature oscillations and fluctuations play a crucial role in driving optimal crystal purification and growth. However, the Office Action completely overlooks the explicit disclosure of Wang, which disproves and rejects Myerson’s entire thermal oscillation premise under high-temperature conditions.
In particular, Wang explicitly states that across tens of high-temperature experiments in aqueous acetic acid, the transformation of crystal shape and growth kinetics reported by Myerson was not found. Wang affirmatively concludes that the primary driving force for purification and growth is not temperature fluctuations, but rather Ostwald ripening under an operational temperature controlled to be as steady as possible to suppress oscillations. A person of ordinary skill in the art faced with these flatly contradictory directives would be left without any predictable framework; following Myerson requires introducing rapid, active thermal variations, while following Wang requires maximizing temperature stability to prevent those exact variations. Because the prior art presents mutually exclusive mechanisms for managing crystal development, Applicants respectfully submits that a person of ordinary skill in the art would have no reasonable expectation of success, exposing the Office Action’s combination as a classic example of hindsight reconstruction.”
This argument has been fully considered, but is not found to be persuasive. As detailed in the maintained rejection above, the Office Action relies on the teachings of Myerson and Wang they both teach the utility of TPA crystal aging as a means for controlling TPA crystal size and decreasing impurity content at temperatures that overlap with the ranges disclosed by List and the ranges recited in instant claims 54 and 75 (c.f., Myerson; page 2091, final paragraph and page 2092, final paragraph; Wang; page 7375; Col. 2, paragraph 6, ‘Conclusions’).
Although Wang agrees with Myerson with the mechanism of crystal purification based on crystal growth and dissolution, Wang does not agree that the driving force is very small temperature fluctuations, but is instead Ostwald ripening (Wang; page 7372, Col. 1, paragraph 5 and Col. 2, paragraph 1), as indicated by Applicant. However, the method of Wang indicates that the slurry vessel was maintained within ±0.5 K of the desired temperature by a PID controlling system shown in Figure 3 (page 7368; Col. 2, paragraph 4). These experimental conditions are similar to the method of Myerson, who teaches several TPA purification examples in acetic acid with about 1 ºC or less temperature oscillations, including amplitudes of 0.2 K, 0.4 K, and 0.6 K (Myerson; page 2092; Figs. 6-8 and 10-11). Therefore, regardless of the accepted mechanism for TPA crystal growth and purification (i.e., small temperature fluctuations as taught by Myerson or Ostwald ripening as taught by Wang), the skilled artisan would not dismiss the teachings of Myerson based on Wang because both of the disclosed methods of TPA crystal aging in acetic acid comprise small temperature fluctuations during the process. Thus, although Wang and Myerson may not agree on the underlying phenomena driving crystal growth and purification, the skilled artisan would arrive at a process comprising small thermal fluctuations based on the teaching of both Wang and Myerson with a reasonable expectation of success.
In response to Applicant’s argument that the Examiner’s conclusion of obviousness is based upon improper hindsight reasoning, it must be recognized that any judgment on obviousness is in a sense necessarily a reconstruction based upon hindsight reasoning. But so long as it takes into account only knowledge which was within the level of ordinary skill at the time the claimed invention was made, and does not include knowledge gleaned only from the applicant's disclosure, such a reconstruction is proper. See In re McLaughlin, 443 F.2d 1392, 170 USPQ 209 (CCPA 1971).
Therefore, the claim rejections are maintained for the reasons of record and the reasons set forth above.
Applicant argues the following:
“Furthermore, Applicant respectfully submits that the Office Action’s assertion that the continuous circulation loop of List can be integrated into Biermann to render the high-temperature limits of independent claim 54 obvious is legally and technically defective. Independent claim 54 explicitly requires that the thermal cycling step occur within a temperature range of 200 ºC or more to 300 ºC or less. However, List explicitly warns that operating an acetic acid-based circulation process at sustained temperatures above 200 ºC is highly uneconomical because the acetic acid solvent is degraded by oxidation, and the underlying industrial installations are severely corroded. In fact, List’s own specific inventive process is structurally bounded by a heating zone at 195 ºC to 210 ºC and a cooling zone at 180 ºC to 195 ºC.
Because List’s crystallization cycle functionally requires cooling the crude dispersion down to a sub-200 ºC range to achieve its target particle size control, List explicitly teaches away from a thermal cycling process conducted exclusively above 200 ºC. Applicant respectfully submits that if a person of ordinary skill in the art was to force the entirety of List’s continuous loop to operate within the 200 ºC to 300 ºC parameters of claim 54, they would systematically destroy the solvent and compromise the equipment. Applicant respectfully submits that List therefore provides a definitive teaching away that defeats the Office Action’s prima facie case.”
These arguments have been fully considered, but are 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 ºC, 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 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:
“Also, the Office Action maintains that the alkaline precipitation step of Biermann and the crystal aging step of the secondary references are separate processing operations that can simply be appended to one another without conflict. This rationale fails to address the chemical reality of the combined matrix and ignores the explicit requirements of the base reference. Biermann explicitly dictates a streamlined continuous reaction flow where the target terephthalic acid must be purified through a rapid, single-instance precipitation step driven by the addition of an acid that is strictly stronger than terephthalic acid, specifically disclosing sulfuric acid.
In direct contrast, List, Myerson, and Wang describe long-term, multi-hour crystal aging and growth kinetics designed specifically for crude solid particles suspended in a saturated weak lower carboxylic acid or acetic acid dispersant matrix. As noted in the record, acetic acid is a weak acid that is completely incapable of serving as the stronger precipitating acid demanded by Biermann’s process chemistry. A person of ordinary skill in the art following the exact high-throughput layout of Biermann would have no reason to fundamentally stall their continuous stream to insert a slow, multi-hour thermal aging loop requiring a completely different, weaker organic solvent matrix. Applicant respectfully submits that stacking these discordant method steps together disrupts the continuous flow of the primary reference, Biermann, confirming that the combination is born entirely from the Office Action’s impermissible hindsight using the Applicant’s own disclosure as a blueprint.”
This argument has been fully considered, but is not found to be persuasive. Both Biermann and List teach continuous processes for the depolymerization of polyethylene terephthalate (Biermann; Abstract, claim 1, English language machine translation; List; Abstract, claim 1). Furthermore, Biermann explicitly teaches that the crude product solution is freed from impurities in an intermediate “purification” step prior to a subsequent “TPA precipitation” step wherein the sulfuric acid is added (0119; English language machine translation). Since Biermann fails to teach a crystal aging method step but does suggest a “purification” method step immediately prior to precipitation with sulfuric acid, 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. 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.
Applicant argues the following:
“Finally, Applicant respectfully submits that the Office Action’s contention that the precipitation step of Biermann and the crystal aging step of List, Myerson, and Wang are separate, fully compatible operations misconstrues the continuous engineering architecture of the primary reference. Biermann is strictly directed to an integrated, high-throughput continuous process. In Biermann’s method, water is continuously injected during depolymerization to directly yield a flowable, low-viscosity saturated aqueous solution of disodium terephthalate, which is then continuously pumped downstream for immediate mechanical filtration and subsequent precipitation.
Conversely, independent claim 75 structurally requires providing the regenerated composition in a liquid medium comprising acetic acid. Forcing a completely separate, weak organic acid solvent loop, like the acetic acid slurry specified in List and Myerson, into Biermann’s continuous aqueous line would fundamentally disrupt the established solubility parameters, ruin the stream viscosity, and directly violate Biermann’s core command that no further reactive constituents be added to the reaction mixture. Because introducing an incompatible acetic acid phase requires breaking the continuity and fluid mechanics of the Biermann’s aqueous stream, Applicant respectfully submits that a person of ordinary skill in the art would have no rational engineering motivation to combine these discordant processes, thereby also fully confirming the patentable distinctness of independent claim 75.”
This argument has been fully considered, but is not found to be persuasive. Since both Biermann and List teach continuous processes (Biermann; Abstract, claim 1, English language machine translation; List; Abstract, claim 1), the argument that the teachings of List, Myerson, and Wang would disrupt the continuous process of Biermann is not persuasive. Furthermore, List teaches that the crude terephthalic acid is purified in a disperse form that utilizes a continuous circulation, may contain up to 10% water, and must fulfill various conditions, including that they are to be capable of being circulated by pumping and must not form sediments in pipelines (List; claim 6; Col. 3, lines 12–28; Col. 5, lines 3-23). Although Biermann does teach that no further reactive constituents be added to the reaction mixture as argued by Applicant, Biermann does teach that a solvent for dissolving solid components is added to the reaction mixture during and/or after the depolymerization (Biermann; claim 1, 0029; English language machine translation). Since List, Myerson, and Wang teach aqueous acetic acid as an optimal solvent for improving TPA purity and controlling TPA crystal size, as detailed above, the skilled artisan would be sufficiently motivated to incorporate these teachings into the method of Biermann 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 Claim Rejections - Double Patenting
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 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 6/18/2026, 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 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, the provisional nonstatutory double patenting rejections of claims 54 and 69-75 over claims 1, 8-9, 12, and 14-15 of copending Application No. 19/238,747 in view of List, Myerson, and Wang, and the nonstatutory double patenting rejections of claims 54-63 and 69-75 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 on record of the previous Office Action dated 3/19/2026 are hereby maintained.
The Examiner notes that filing a terminal disclaimer will ameliorate these double patenting rejections.
Conclusion
No claims are allowed.
Applicant’s amendment under 37 CFR 1.97(c) with the fee set forth in 37 CFR 1.17(p) on 6/18/2026 necessitated and prompted the maintained 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 extension fee 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.
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/D.R./Examiner, Art Unit 1692
/AMY C BONAPARTE/Primary Examiner, Art Unit 1692
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