Notice of Pre-AIA or AIA Status
The present application, filed on or after March 16, 2013, is being examined under the first inventor to file provisions of the AIA .
Response to Amendment
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Any rejections and/or objections made in the previous Office action and not repeated below are hereby withdrawn.
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a).
Claim Rejections - 35 USC § 112
Claim 14 is rejected under 35 U.S.C. 112(d) or pre-AIA 35 U.S.C. 112, 4th paragraph, as being of improper dependent form for failing to further limit the subject matter of the claim upon which it depends, or for failing to include all the limitations of the claim upon which it depends.
Claim 14 indicates the difference between the 20-40 degrees C washing and the 70-110 degrees C washing is 30-100 degrees. However, the feasible minimum difference is 70-40 = 30 degrees and the feasible maximum difference is 110-20 = 90 degrees. Therefore, claim 14 fails to further limit the subject matter of the claim upon which it depends.
Applicant may cancel the claim(s), amend the claim(s) to place the claim(s) in proper dependent form, rewrite the claim(s) in independent form, or present a sufficient showing that the dependent claim(s) complies with the statutory requirements.
Claim Rejections - 35 USC § 103
Claim(s) 7-11 and 13-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Bruson (U.S. Pat. No. 2,857,429).
Regarding Claims 7 and 8, England teaches methods of preparing terephthalic acid monomer comprising subjecting polyethylene terephthalate to a depolymerization reaction to yield disodium terephthalate, filtering to remove diol component, and acidifying to yield terephthalic acid (Example 2). During acidification, terephthalic acid precipitates, which is washed with distilled water (Col. 6, Lines 6-11), corresponding to washing with a protic polar solvent. A temperature is not specified in Example 2, which infers room temperature rinsings. England differs from the subject matter claimed in that a step of washing with aprotic polar solvent is not described.
Bruson also pertains to the isolation/purification of terephthalic acid (Col. 1, Lines 15-18). Bruson teaches it was known in the art terephthalic acid can have low solubility in various aprotic ether/ketone solvents, such that they can be used to remove isophthalic acid and other organic impurities without appreciably dissolving the terephthalic acid (Col. 2, Lines 5-15). It would have been obvious to one of ordinary skill in the art to wash the obtained terephthalic acids of England with the aprotic solvents of Bruson because doing so would facilitate the removal of organic impurities without appreciably dissolving the terephthalic acid as taught by Bruson.
Bruson teaches embodiments where organic solvent is used close to the boiling point of solvent (Col. 2, Lines 10-11) and indicates dioxane (boiling point 101.3 degrees C) is preferred (Table I; Example 1). Bruson teaches embodiments where solvent is used 10-40 times the weight of acid mixture (Claim 1). As polyethylene terephthalate is roughly 77 wt% terephthalic acid residues, the combination of references is suggestive of embodiments where roughly 10-40 / [1 / 0.77] = 7.7 to 30.8 pbw solvent relative to 1 pbw PET used. The disclosed range overlaps the range claimed. It would have been obvious to one of ordinary skill in the art to use a range within the claimed range because a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art and Bruson suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Bruson. See MPEP 2123.
Regarding Claim 9, Bruson teaches several solvents are suitable, including THF (Table 1). While not describing combinations of solvents, it is well settled that it is prima facie obvious to combine two ingredients, each of which is targeted by the prior art to be useful for the same purpose. In re Crockett, 279 F.2d 274, 126 USPQ 186 (CCPA 1960). Ex parte Quadranti, 25 USPQ2d 1071 (Bd. Pat. App. & Inter. 1992). Since Bruson teaches each solvent is suitable for the same purpose, it would have been obvious to one of ordinary skill in the art to utilize combinations of solvents comprising THF, thereby predictably affording the purification of terephthalic acid.
Regarding Claim 10, England teaches washing with water after neutralization to remove residual water soluble salts resulting from neutralization to obtain crude terephthalic acid and then drying (Col. 4, Lines 49-59). Bruson teaches treating crude acid with aprotic solvent, filtering, washing with water, and then drying (Examples). As the solids are ultimately dried at the end of Bruson’s process, it would have been obvious to one of ordinary skill in the art to omit drying after England’s water washing, thereby eliminating costs associated with heating and transfer. A crude acid mixture with residual water treated with aprotic solvent is seen to read on claim 10, which requires a mixture of aprotic polar solvent and the protic solvent used in washings.
Regarding Claim 11, England teaches washing with seven 300 mL portions of distilled water relative to 110 grams of polyethylene terephthalate (Example 2), equivalent to roughly 19 pbw of water relative to 1 pbw PET. A temperature is not specified in Example 2, which infers room temperature rinsings.
Regarding Claim 13, England teaches washing with water after neutralization to recover crude terephthalic acid (Example 2) and Bruson teaches further purification of crude terephthalic acid to remove organic impurities. Accordingly, the combination of references is suggestive of embodiments where washing with aprotic solvent occurs after washing with protic solvent.
Regarding Claim 14, Bruson teaches embodiments where organic solvent is used close to the boiling point of solvent (Col. 2, Lines 10-11) and indicates dioxane (boiling point 101.3 degrees C) is preferred (Table I; Example 1). A temperature is not specified in Example 2 of England, which infers room temperature rinsings. Accordingly, the combination of references suggests temperature differences of roughly 101.3-24 = 77.3 degrees C.
Regarding Claims 15-17, England teaches depolymerizing PET with sodium hydroxide base in the presence of ethylene glycol solvent, whereby after filtering to remove diol component the resulting disodium terephthalate is neutralized with an acid prior to washing (Example 2). A stoichiometric amount of hydroxide relative to terephthaloyl content in PET is used (Col. 5, Lines 49-52), equivalent to roughly 2 moles of base relative to 1 mole of PET.
Claim(s) 7-11 and 13-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Horn (U.S. Pat. No. 2,822,388) as evidenced by Essaddam (US 2017/0008826 A1).
Regarding Claims 7 and 8, England teaches methods of preparing terephthalic acid monomer comprising subjecting polyethylene terephthalate to a depolymerization reaction to yield disodium terephthalate, filtering to remove diol component, and acidifying to yield terephthalic acid (Example 2). During acidification, terephthalic acid precipitates, which is washed with distilled water (Col. 6, Lines 6-11), corresponding to washing with a protic polar solvent. A temperature is not specified in Example 2, which infers room temperature rinsings. Alternatively, England teaches boiling water (~ 100 degrees C) can be used (Col. 6, Lines 69-71). England differs from the subject matter claimed in that a step of washing with aprotic polar solvent is not described.
As evidenced by Essaddam, the depolymerization of polyethylene terephthalate gives rise to impurities such as 4-methylbenzoic acid (toluic acid) (Abstract; ¶ 84). Horn also pertains to the isolation/purification of terephthalic acid (Col. 1, Lines 18-32). Horn teaches it was known in the art acetonitrile can be used to wash crude terephthalic acids to effectively remove impurities such as toluic acid (Col. 1, Line 51 to Col. 2, Line 23). It would have been obvious to one of ordinary skill in the art to wash the obtained terephthalic acids of England with acetonitrile because doing so would facilitate the removal of organic impurities such as toluic acid as taught by Horn.
Horn teaches embodiments where boiling acetonitrile is used (Col. 1, Line 71 to Col. 2, Line 1). The boiling point of acetonitrile is roughly 82 degrees C. Horn teaches embodiments where boiling acetonitrile is used (Col. 1, Line 71 to Col. 2, Line 1). The boiling point of acetonitrile is roughly 82 degrees C. While Horn does not provide a preferred pbw range of acetonitrile relative to 1 pbw PET, Horn nonetheless notes the ability to remove impurities depends on the quantity of solvent used, whereby toluic acid can be dissolved in roughly 12.4 g per 100 g acetonitrile (Col. 1, Lines 55-65). See for instance Example 2 where multiple extractions of excess acetonitrile is used in order to effect further purification. Thus, the quantity of acetonitrile used is a known result effective variable subject to routine optimization by one of ordinary skill in the art. See MPEP 2144.05(II). Case law holds that “discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art.” See In re Boesch, 617 F.2d 272, 205 USPQ 215 (CCPA 1980). In view of this, it would have been obvious to one of ordinary skill in the art to discover workable/optimal quantities of aprotic solvent within the scope of the present claims so as to produce desired removal of impurities.
Regarding Claim 10, England teaches washing with water after neutralization to remove residual water soluble salts resulting from neutralization to obtain crude terephthalic acid and then drying (Col. 4, Lines 49-59). Horn teaches treating crude acid with aprotic solvent and filtering (Col. 1, Lines 65-70; Examples), whereby drying/removal of volatile acetonitrile is implied. As the solids are ultimately dried at the end of Horn’s process, it would have been obvious to one of ordinary skill in the art to omit drying after England’s water washing, thereby eliminating costs associated with heating and transfer. A crude acid mixture with residual water treated with aprotic solvent is seen to read on claim 10, which requires a mixture of aprotic polar solvent and the protic solvent used in washings.
Regarding Claim 11, England teaches washing with seven 300 mL portions of distilled water relative to 110 grams of polyethylene terephthalate (Example 2), equivalent to roughly 19 pbw of water relative to 1 pbw PET. A temperature is not specified in Example 2, which infers room temperature rinsings.
Regarding Claim 13, England teaches washing with water after neutralization to recover crude terephthalic acid (Example 2) and Horn teaches further purification of crude terephthalic acid to remove organic impurities. Accordingly, the combination of references is suggestive of embodiments where washing with aprotic solvent occurs after washing with protic solvent.
Regarding Claim 14, Horn teaches embodiments where boiling acetonitrile is used (Col. 1, Line 71 to Col. 2, Line 1). The boiling point of acetonitrile is roughly 82 degrees C. A temperature is not specified in Example 2 of England, which infers room temperature rinsings. Accordingly, the combination of references suggests temperature differences of roughly 82-24 = 58 degrees C.
Regarding Claims 15-17, England teaches depolymerizing PET with sodium hydroxide base in the presence of ethylene glycol solvent, whereby after filtering to remove diol component the resulting disodium terephthalate is neutralized with an acid prior to washing (Example 2). A stoichiometric amount of hydroxide relative to terephthaloyl content in PET is used (Col. 5, Lines 49-52), equivalent to roughly 2 moles of base relative to 1 mole of PET.
Claim(s) 7, 8, 10, 11 and 13-17 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (U.S. Pat. No. 3,544,622) in view of Hetzel (U.S. Pat. No. 3,043,870).
Regarding Claims 7, 8, and 10, England teaches methods of preparing terephthalic acid monomer comprising subjecting polyethylene terephthalate to a depolymerization reaction to yield disodium terephthalate, filtering to remove diol component, and acidifying to yield terephthalic acid (Example 2). During acidification, terephthalic acid precipitates, which is washed with distilled water (Col. 6, Lines 6-11), corresponding to washing with a protic polar solvent. A temperature is not specified in Example 2, which infers room temperature rinsings. England differs from the subject matter claimed in that a step of washing with aprotic polar solvent is not described.
Hetzel also pertains to the isolation/purification of terephthalic acid (Col. 1, Lines 10-13). Hetzel teaches it was known mixtures of alcohol and aprotic alkyl aryl ketone is capable of dissolving isophthalic acid impurities while leaving terephthalic acid behind undissolved (Col. 1, Lines 34-71). Minor amounts of water can be present (Col. 1, Lines 38-39). It would have been obvious to one of ordinary skill in the art to wash the obtained terephthalic acids of England with the aprotic solvents of Hetzel because doing so would facilitate the removal of organic impurities without appreciably dissolving the terephthalic acid as taught by Hetzel.
Hetzel teaches employing the solvents at 125-250 degrees F (Col. 2, Lines 5-8), equivalent to roughly 52-121 degrees C. Hetzel teaches using solvent at 5-30 times the weight of crude TPA (Col. 1, Lines 68 to Col. 2, Line 4). As polyethylene terephthalate is roughly 77 wt% terephthalic acid residues, the combination of references is suggestive of embodiments where roughly 5-30 / [1 / 0.77] = 3.9 to 23.1 pbw solvent relative to 1 pbw PET used. The disclosed ranges overlap the ranges claimed. It would have been obvious to one of ordinary skill in the art to use a range within the claimed range because a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art and Hetzel suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of Hetzel. See MPEP 2123.
Regarding Claim 11, England teaches washing with seven 300 mL portions of distilled water relative to 110 grams of polyethylene terephthalate (Example 2), equivalent to roughly 19 pbw of water relative to 1 pbw PET. A temperature is not specified in Example 2, which infers room temperature rinsings.
Regarding Claim 13, England teaches washing with water after neutralization to recover crude terephthalic acid (Example 2) and Hetzel teaches further purification of crude terephthalic acid to remove organic impurities. Accordingly, the combination of references is suggestive of embodiments where washing with aprotic solvent occurs after washing with protic solvent.
Regarding Claim 14, Hetzel teaches employing the solvents at 125-250 degrees F (Col. 2, Lines 5-8), equivalent to roughly 52-121 degrees C. A temperature is not specified in Example 2 of England, which infers room temperature rinsings. Accordingly, the combination of references suggests temperature differences of roughly [52 to 121] - 24 = 28 to 97 degrees C. The range overlaps the range claimed. It would have been obvious to one of ordinary skill in the art to use a range within the claimed range because a reference may be relied upon for all that it would have reasonably suggested to one having ordinary skill the art and the prior art suggests the claimed range. A person of ordinary skill would be motivated to use the claimed amount, based on the teachings of the prior art. See MPEP 2123.
Regarding Claims 15-17, England teaches depolymerizing PET with sodium hydroxide base in the presence of ethylene glycol solvent, whereby after filtering to remove diol component the resulting disodium terephthalate is neutralized with an acid prior to washing (Example 2). A stoichiometric amount of hydroxide relative to terephthaloyl content in PET is used (Col. 5, Lines 49-52), equivalent to roughly 2 moles of base relative to 1 mole of PET.
Response to Arguments
Applicant's arguments filed 3/19/2026 have been fully considered but they are not persuasive.
Applicant generally argues the claims as amended distinguish the claims from the prior art. This is not found persuasive for reasons set forth above.
Applicant alleges unexpected results, namely the washing protocol yields TPA with isophthalic acid content of 0 mol%. This is not found persuasive.
Bruson teaches it was already well known (at least since 1958) that washing with aprotic solvent is an effective means of removing isophthalic acid impurities from terephthalic acid. See also newly cited Hetzel. Applicant’s observations lack significance to the extent that they can be regarded as unexpected.
Even arguendo such results were unexpected, the claims at issue are not commensurate in scope with the evidence offered in support of unexpected results. The data only corresponds with terephthalic acid, but there appears to be no indication the monomer composition obtained is pure terephthalic acid with 0 mol% IPA within the claims. The data only illustrates water and either THF or acetonitrile in contrast to the more generic “washing solvent containing an aprotic solvent” and “protic polar solvent”.
Conclusion
Applicant's amendment necessitated the new ground(s) of rejection presented in this Office action. Accordingly, THIS ACTION IS MADE FINAL. See MPEP § 706.07(a). Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
A shortened statutory period for reply to this final action is set to expire THREE MONTHS from the mailing date of this action. In the event a first reply is filed within TWO MONTHS of the mailing date of this final action and the advisory action is not mailed until after the end of the THREE-MONTH shortened statutory period, then the shortened statutory period will expire on the date the advisory action is mailed, and any nonprovisional extension fee (37 CFR 1.17(a)) pursuant to 37 CFR 1.136(a) will be calculated from the mailing date of the advisory action. In no event, however, will the statutory period for reply expire later than SIX MONTHS from the mailing date of this final action.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to STEPHEN E RIETH whose telephone number is (571)272-6274. The examiner can normally be reached Monday - Friday, 8AM-4PM Mountain Standard Time.
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If attempts to reach the examiner by telephone are unsuccessful, the examiner’s supervisor, Curtis Mayes can be reached at (571)272-1234. The fax phone number for the organization where this application or proceeding is assigned is 571-273-8300.
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/STEPHEN E RIETH/Primary Examiner, Art Unit 1759
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