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 1-20 are pending as amended on 3/30/2023.
Election/Restrictions
Applicant’s election without traverse of Group II (claims 7-15), and species wherein the dissolution/recrystallization conditions are as recited in claim 11, in the reply filed on 11/12/2025 is acknowledged. Claims 1-6, 12 and 16-20 are withdrawn from further consideration pursuant to 37 CFR 1.142(b) as being drawn to a nonelected invention/species, there being no allowable generic or linking claim.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
Claim(s) 7-11 and 13-15 is/are rejected under 35 U.S.C. 103 as being unpatentable over England (US 3544622) in view of Taylor et al (US 3574727), Standard Oil Company (GB 1152575) and Zubrick (The Organic Chem Lab Survival Manual; 1988, John Wiley and Sons, pp 91-110).
As to claims 7, 8, 14 and 15, England discloses a method for the recovery of disodium salt of terephthalic acid and terephthalic acid itself from scrap PET (Col 1, lines 29-37). England discloses alkaline saponification of PET in the presence of water and ethylene glycol (solvents which are recited in instant claim 14) using sodium hydroxide (col 1, lines 44-56, which corresponds to the presently recited “subjecting” step of depolymerizing a polymer synthesized from terephthalic acid, i.e., PET), and then separating the disodium terephthalate which precipitates from the mother liquor by filtration (col 1, line 71 to col 2, line 2; which corresponds to the presently recited step of removing a diol component, because the diol component remains in the mother liquor; see col 3, lines 72-75).
England discloses converting the disodium terephthalate to terephthalic acid by dissolving in water (col 4, lines 35-37) and neutralizing with a strong acid such as hydrochloric acid (col 4, lines 49-53), and then washing with successive portions of water to remove occluded soluble salts (col 4, lines 56-59), which corresponds to the step of neutralizing the depolymerization reaction product from which diol has been removed with an acid, as recited in claim 15, and which meets the “washing” step recited in claim 7, wherein the solvent for the washing is water, as recited in claim 8. The neutralization in England’s process occurs before the washing step with successive portions of water (meeting the requirement in claim 15 of neutralizing before the washing step). England does not disclose heating or cooling the water used for the step of washing the filter cake of terephthalic acid, and therefore, one having ordinary skill in the art would have at least envisaged the use of room temperature water (i.e., 20~25 C, which falls within the range of 20 C or more to 100 C or less recited in claim 7) for carrying out England’s disclosed step of washing to remove occluded salts.
England does not disclose purifying the obtained terephthalic acid by recrystallization, and therefore, fails to teach the presently recited steps of dissolving the washed terephthalic acid and cooling the solution to recrystallize terephthalic acid.
One having ordinary skill in synthetic chemistry would have recognized that recrystallization is a common purification technique: a desired (impure) substance is dissolved in a solvent, and the solution is then cooled to a temperature at which the desired substance precipitates from the solution in the form of crystals. The crystals of desired substance can then be separated from the solvent and from impurities, which remain dissolved in the solvent, such as by filtration and washing of the desired crystals. If evidence is needed that this basic knowledge is known to one of ordinary skill in the art, see Zubrick’s Chapter on Recrystallization starting on p 91, particularly, the discussion at the top of p 92 (points 1-3) and the bottom of p 97.
Taylor discloses a process for purifying crude terephthalic acid (col 1, lines 21-22). Taylor discloses that a further reduction in impurities in recovered terephthalic acid can be realized by recrystallizing from water. Taylor discloses heating to a temperature between 240-280 C with sufficient pressure to maintain the water in a liquid state. The terephthalic acid is dissolved in the heated solution, and then subsequently cooled to room temperature so as to precipitate additionally purified terephthalic acid, which may be recovered by filtration (col 3, lines 61-73).
Standard Oil also discloses the purification of aromatic polycarboxylic acids (p 1, lines 11-16), and teaches that because terephthalic acid has low solubility in water, either large volumes of water or high temperatures are required in order for the desired terephthalic acid quantity to be put into solution (p 2, line 126 to p 3, line 4). Standard Oil provides a table showing the amounts of terephthalic acid which can be dissolved in 100 g of water at temperatures ranging from 365-522 F (i.e., 185-272 C).
Considering the level of ordinary skill in the art and the disclosures of Taylor and Standard Oil as set forth above, one would have known generally suitable conditions for the recrystallization of terephthalic acid using water as a solvent in order to remove impurities from terephthalic acid. When carrying out the recrystallization of terephthalic acid in water, the person having ordinary skill in the art would have been motivated to select an appropriate temperature for heating terephthalic acid in water (such as within a range of 185-272 C as in Standard Oil, or 240-280 C, as in Taylor) in order to dissolve the terephthalic acid in a given volume of water. The person having ordinary skill in the art would have been subsequently motivated to slowly cool the solution to any appropriate temperature at which terephthalic acid is no longer soluble in water (and at which the undesired impurities remain soluble in water) in order to precipitate/crystallize the terephthalic acid while keeping impurities dissolved in the solvent. It would have been obvious to the person having ordinary skill in the art, therefore, to have increased the degree of purity of England’s recovered terephthalic acid by dissolving the terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C (including a temperature which falls within the presently claimed range of 200-300 C), and by then slowly cooling the aqueous solution to any appropriate temperature at which terephthalic is insoluble in water (including a temperature which is 50 to 200 C lower than the dissolution temperature) in order to provide terephthalic acid crystals having an increased degree of purity.
As to claim 9, modified England suggests a process according to claim 7, as set forth above. As set forth above, England discloses washing the terephthalic acid with successive portions of water to remove occluded soluble salts (col 4, lines 56-59), but does not indicate the volume or quantity of water used in the washing step. However, one would have recognized that as the quantity of water used to wash England’s solid terephthalic acid product increases, the amount of impurities (e.g., occluded soluble salts) washed away by the water increases, and therefore the degree of the purity of the desired terephthalic acid substance increases. However, one would have also understood that as the volume of water used to wash a substance increases, the efficiency (in terms of, e.g., time, consumption of water, and production wastewater) of a purification process decreases. It would have been obvious to the person having ordinary skill in the art, therefore, to have utilized any appropriate amount of water in England’s washing step in order to achieve a desired reduction in impurities balanced with a desired process efficiency, including a volume of water within the presently claimed range.
As to claims 10 and 11, modified England suggests a process according to claim 7, as set forth above, which includes a step of crystallizing terephthalic acid by dissolving terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C, including a temperature which falls within the presently claimed range of 200-300 C (or 200-220 C in claim 11). As evidenced by the table on p 3 of Standard Oil, one having ordinary skill in the art would have recognized that when dissolving terephthalic acid in water, the amount of water needed to dissolve a given quantity of terephthalic acid increases as the temperature of the water decreases. Given that the relationship between terephthalic solubility and water temperature was known in the art, it would have been well within the level of skill in the art to determine an appropriate quantity of water for dissolving a given quantity of terephthalic acid at a given water temperature.
It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out the recrystallization step in the process of modified England by selecting any appropriate dissolution water temperature at which terephthalic acid is soluble, including within the presently claimed range of 200-300 C (or 200-220 C), and by determining and utilizing any appropriate quantity of water which dissolves the desired quantity of terephthalic acid, including a quantity of water within the presently claimed range of 1-60 parts by weight (or 30-60 parts by weight) based on 1 part by weight of copolymer.
As to claim 13, England discloses that the amount of sodium hydroxide is at least stoichiometric based on the terephthalyl values to be recovered, but not in excess of about 10% over stoichiometric. England teaches that less than stoichiometric results in incomplete saponification, while more than 10% over stoichiometric results formation of undesirable degradation products which cause discoloration (col 1, lines 50-64). A stoichiometric amount of sodium hydroxide relative to 1 mole of terephthalic acid to be recovered is 2 moles of sodium hydroxide, because each terephthalic acid has two carboxylic groups, and therefore a stoichiometric amount of sodium hydroxide, as taught by England, falls within the presently claimed range of 2.3 moles or less. It would have been obvious to the person having ordinary skill in the art to have utilized 2 moles of base (sodium hydroxide) relative to 1 mole of terephthalic acid in the copolymer, as taught by England, in order to achieve complete saponification while avoiding the formation of undesirable degradation products.
Claim(s) 7-11 and 14 is/are rejected under 35 U.S.C. 103 as being unpatentable over Smuda (US 6239310) in view of Taylor et al (US 3574727), Standard Oil Company (GB 1152575) and Zubrick (The Organic Chem Lab Survival Manual; 1988, John Wiley and Sons, pp 91-110).
As to claims 7, 8 and 14, Smuda discloses heating polyethylene terephthalate (PET, i.e., a polymer synthesized from terephthalic acid) with a reagent substance in aqueous solution (col 2, lines 12-18), after which the PET is “digested” (corresponding to the presently recited “depolymerization reaction” carried out in the presence of water, as recited in claims 7 and 14), resulting in an aqueous solution of terephthalic acid salts (col 2, lines 19-21).
Smuda teaches filtering, neutralization and separation of terephthalic acid (col 2, lines 20-25 and lines 49-51), corresponding to the presently recited step of removing a diol component (i.e., by separating it from the terephthalic acid).
Smuda teaches washing the terephthalic acid with water (col 2, lines 25 and 53-54). The water used for the step of washing disclosed by Smuda corresponds to a solvent as recited in claims 7 and 8. Smuda does not disclose the use of heated water for the washing step, and therefore, at least the use of room temperature water (~25 C, which falls within the claimed range of 20-100 C) for the washing step would have been immediately envisaged by one having ordinary skill in the art.
Smuda further discloses crystallization of terephthalic acid from water (col 2, lines 26 and 54). However, Smuda fails to provide conditions for crystallization of terephthalic acid from water, and therefore, fails to teach the presently recited steps of dissolving and recrystallizing the washed terephthalic acid.
One having ordinary skill in synthetic chemistry would have recognized that recrystallization is a common purification technique: a desired (impure) substance is dissolved in a solvent, and the solution is then cooled to a temperature at which the desired substance precipitates from the solution in the form of crystals. The crystals of desired substance can then be separated from the solvent and from impurities, which remain dissolved in the solvent, such as by filtration and washing of the desired crystals. If evidence is needed that this basic knowledge is known to one of ordinary skill in the art, see Zubrick’s Chapter on Recrystallization starting on p 91, particularly, the discussion at the top of p 92 (points 1-3) and the bottom of p 97.
Taylor discloses a process for purifying crude terephthalic acid (col 1, lines 21-22). Taylor discloses that a further reduction in impurities in recovered terephthalic acid can be realized by recrystallizing from water. Taylor discloses heating to a temperature between 240-280 C with sufficient pressure to maintain the water in a liquid state. The terephthalic acid is dissolved in the heated solution, and then subsequently cooled to room temperature so as to precipitate additionally purified terephthalic acid, which may be recovered by filtration (col 3, lines 61-73).
Standard Oil also discloses the purification of aromatic polycarboxylic acids (p 1, lines 11-16), and teaches that because terephthalic acid has low solubility in water, either large volumes of water or high temperatures are required in order for the desired terephthalic acid quantity to be put into solution (p 2, line 126 to p 3, line 4). Standard Oil provides a table showing the amounts of terephthalic acid which can be dissolved in 100 g of water at temperatures ranging from 365-522 F (i.e., 185-272 C).
Considering the level of ordinary skill in the art and the disclosures of Taylor and Standard Oil as set forth above, one would have known generally suitable conditions for the recrystallization of terephthalic acid using water as a solvent in order to remove impurities from terephthalic acid. When carrying out the recrystallization of terephthalic acid in water, the person having ordinary skill in the art would have been motivated to select an appropriate temperature for heating terephthalic acid in water (such as within a range of 185-272 C as in Standard Oil, or 240-280 C, as in Taylor) in order to dissolve the terephthalic acid in a given volume of water. The person having ordinary skill in the art would have been subsequently motivated to slowly cool the solution to any appropriate temperature at which terephthalic acid is no longer soluble in water (and at which the undesired impurities remain soluble in water) in order to precipitate/crystallize the terephthalic acid while keeping impurities dissolved in the solvent. It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out Smuda’s disclosed step of crystallizing terephthalic acid by dissolving terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C (including a temperature which falls within the presently claimed range of 200-300 C), and by then slowly cooling the aqueous solution to any appropriate temperature at which terephthalic is insoluble in water (including a temperature which is 50 to 200 C lower than the dissolution temperature) in order to provide terephthalic acid crystals having an increased degree of purity.
As to claim 9, modified Smuda suggests a process according to claim 7, as set forth above. Smuda teaches that the product is “washed with distilled water” (col 2, line 52), but does not indicate the volume or quantity of water used in the washing step. One having ordinary skill in the art would have recognized that a washing step as taught by Smuda is performed in order to remove impurities from the surface of a solid desired product. One would have recognized that as the quantity of water used to wash the solid product increases, the amount of impurity washed away by the water increases, and therefore the degree of the purity of the desired substance increases. However, one would have also understood that as the volume of water used to wash a substance increases, the efficiency (in terms of, e.g., time, consumption of water, and production wastewater) of a purification process decreases. It would have been obvious to the person having ordinary skill in the art, therefore, to have utilized any appropriate amount of water in Smuda’s washing step in order to achieve a desired reduction in impurities balanced with a desired process efficiency, including a volume of water within the presently claimed range.
As to claims 10 and 11, modified Smuda suggests a process according to claim 7, as set forth above, which includes a step of crystallizing terephthalic acid by dissolving terephthalic acid in water at any appropriate temperature within Standard Oil’s range of 185-272 C, including a temperature which falls within the presently claimed range of 200-300 C (or 200-220 C in claim 11). As evidenced by the table on p 3 of Standard Oil, one having ordinary skill in the art would have recognized that when dissolving terephthalic acid in water, the amount of water needed to dissolve a given quantity of terephthalic acid increases as the temperature of the water decreases. Given that the relationship between terephthalic solubility and water temperature is known in the art, it would have been well within the level of skill in the art to determine an appropriate quantity of water for dissolving a given quantity of terephthalic acid at a given water temperature.
It would have been obvious to the person having ordinary skill in the art, therefore, to have carried out the recrystallization step in the process of modified Smuda by selecting any appropriate dissolution water temperature at which terephthalic acid is soluble, including within the presently claimed range of 200-300 C (or 200-220 C), and by determining and utilizing any appropriate quantity of water which dissolves the desired quantity of terephthalic acid, including a quantity of water within the presently claimed range of 1-60 parts by weight (or 30-60 parts by weight) based on 1 part by weight of copolymer.
Conclusion
Any inquiry concerning this communication or earlier communications from the examiner should be directed to RACHEL KAHN whose telephone number is (571)270-7346. The examiner can normally be reached Monday to Friday, 8-5.
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/RACHEL KAHN/Primary Examiner, Art Unit 1766