DETAILED ACTION
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 .
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.
Continued Examination Under 37 CFR 1.114
A request for continued examination under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after allowance or after an Office action under Ex Parte Quayle, 25 USPQ 74, 453 O.G. 213 (Comm'r Pat. 1935). Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, prosecution in this application has been reopened pursuant to 37 CFR 1.114. Applicant's submission filed on 29 April 2026 has been entered.
The prior Notice of Allowability is withdrawn.
Information Disclosure Statements
The Information Disclosure Statement filed on 29 April 2026 has been received and considered by the Examiner.
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.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or nonobviousness.
Claims 1-5 and 9-10 are rejected under 35 U.S.C. 103 as being unpatentable over Park et al. (KR 20130010353 A) in view of ACS (“Azeotropic Data”, Advances in Chemistry Series, Vol. 6, American Chemical Society, 1952) and Jacquet et al. (US 4,826,681). The provided English translation of Park (KR 20130010353 A) is relied upon in the analysis below; translations of Figure 3 and Table 1 are included below.
Regarding claim 1, Park teaches a continuous process for removing water from a hydrogen peroxide solution ([0001] and [0037]) , the process comprising:
a) combining a fresh non-aqueous solvent stream and an aqueous hydrogen peroxide solution stream in a mixing vessel to form a first mixture comprising the fresh non-aqueous solvent (azeotroping agent), hydrogen peroxide, and water (supplying an azeotropic agent… to hydrogen peroxide containing water; [0021], and Figure 3 shows the mixing vessel)
b) separating the first mixture into:
(i) a first stream comprising a first portion of the non-aqueous solvent and a majority of the water present in the first mixture (steam corresponding to the azeotropic composition of water and the azeotropic agent is discharged to the top of the tower; [0033]), and
(ii) a second stream comprising a majority of the hydrogen peroxide present in the first mixture, wherein the second stream comprises ~4 wt% water (Table 1; tower bottoms contains nearly all the hydrogen peroxide and 4.12% water relative to H2O2 plus H2O); and.
c) separating the first stream into a non-aqueous solvent fraction and a water fraction (In the reflux drum (17), the water layer and the azeotropic layer are separated, so the water layer is discarded and the azeotropic layer is refluxed to the top of the tower using a reflux pump; [0034]).
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Table 1 of Park, with translated column headers.
Regarding the second stream comprising a second portion of the non-aqueous solvent, while Park is silent on the amount of the non-aqueous solvent remaining in the second stream, it is reasonable to conclude that at least some of it remains in the column bottoms along with the hydrogen peroxide. In particular, because the continuous method is constantly adding the non-aqueous solvent back into the hydrogen peroxide mixture, as long as this is occurring there will be some non-aqueous solvent present in the second stream. Additionally, Park teaches that non-aqueous solvent needs to be added back into the system as it is partially consumed by being removed with the hydrogen peroxide product (Meanwhile, the hydrogen peroxide concentrated in the reboiler is discharged using a pump and processed into a product. The azeotropic agent consumed during this process is supplied through the reflux drum; [0035]-[0036]). This also means that while Park describes their method as concentrating and removing water from hydrogen peroxide, it is also a method to generate a non-aqueous hydrogen peroxide solution.
Park does not teach the non-aqueous solvent (azeotropic agent) being tert-butanol, and instead teaches that the solvent can be one of normal hexane, cyclohexane, benzene, toluene, and xylene ([0018]). However, ACS teaches that tert-butanol has similar azeotropic properties to multiple compounds that Park teaches are suitable azeotropic agents (e.g. toluene, cyclohexane, and benzene), as shown in the table below using data from ACS.
Azeotropic Agent
Boiling Point (°C)
Azeotropic Point (°C)
Azeotropic Composition (wt% H2O)
Ref. Entry a
toluene
110.7
84.1
13.5
357
tert-butanol
82.5
79.9
11.76
224
cyclohexane
80.75
68.95
9
315
benzene
80.2
69.25
8.83
295
a Entry number in Table I of “Azeotropic Data”, Advances in Chemistry Series, Vol. 6, American Chemical Society, 1952.
Furthermore, Jacquet teaches a similar azeotropic distillation process for generation of non-aqueous hydrogen peroxide solutions (column 3, lines 21-25), and Jacquet further discloses the use of alcohols with 2 to 20 carbons (col. 2, lines 3-4), which include tert-butanol (a 4 carbon alcohol), and additionally teaches that like the cyclohexane used by Park, tert-butanol also forms an azeotrope with water (column 3, lines 37-38).
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to replace the non-aqueous solvent (azeotropic agent) used by Park with the alternate non-aqueous solvent of tert-butanol, which is also known to form azeotropes with water and has been used successfully in combination with hydrogen peroxide, as taught by ACS and Jacquet. One of ordinary skill in the art would have been motivated to do so because they would have been simply replacing one azeotrope forming solvent with another.
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Figure 3 of Park shown an apparatus for operation of the continuous process for producing dried hydrogen peroxide; the apparatus labels have been replaced with English machine translations.
Regarding claim 2, modified Park teaches the continuous process of claim 1, and further teaches recycling at least a portion of the non-aqueous solvent fraction of the first stream into the fresh aqueous solvent stream of step a) (an azeotropic agent is supplied to the reflux drum… steam corresponding to the azeotropic composition of water and the azeotropic agent is discharged to the top of the tower. The discharged steam is condensed in the condenser and discharged into the reflux drum…the azeotropic layer is refluxed to the top of the tower using a reflux pump; [0032]-[0034] and Figure 3).
Regarding claim 3, modified Park teaches the continuous process of claim 1, and the additional limitations of the instant claim describe merely the dilution of the recovered non-aqueous hydrogen peroxide solution with non-aqueous solvent recovered from the process. Park teaches that the non-aqueous fraction of the first stream is recovered and can be reused ([0019]-[0020], but does not specifically teach mixing it with the second stream to form a second mixture.
However, Jacquet teaches that it will sometimes be necessary to dilute the second stream of recovered hydrogen peroxide with additional solvent in order to control the hydrogen peroxide concentration (column 4, lines 18-22). Dilution will necessarily lower the concentration in the mixture created from the second stream.
Therefore, it would have been obvious to one of ordinary skill in the art, before the effective filing date of the claimed invention, to combine at least a portion of the non-aqueous solvent fraction of the first stream with the second stream of modified Park to form a second mixture comprising the non-aqueous solvent and hydrogen peroxide, where the hydrogen peroxide is present in a lower concentration in the second mixture than in the second stream, as taught by Jacquet. One of ordinary skill would have been motivated to do so because Jacquet teaches that dilution of the second stream is sometimes desired and can be accomplished with any miscible solvent, while Park teaches that this recovered non-aqueous solvent fraction of the first stream, which is a miscible solvent, can be reused.
Regarding claim 4, modified Park teaches the continuous process of claim 1, wherein step b) of separating the first mixture into the first stream and the second stream comprises an azeotropic distillation of the first mixture to provide the first stream as an overhead fraction and the second stream as a bottom fraction in the distillation process (concentrated hydrogen peroxide exists in the reboiler, and a concentration gradient or temperature gradient is formed from the bottom of the distillation section to the top of the recovery section, and steam corresponding to the azeotropic composition of water and the azeotropic agent is discharged to the top of the tower; [0033] and Figure 3).
Regarding claim 5, modified Park teaches the continuous process of claim 4, wherein the azeotropic distillation is conducted under vacuum (a vacuum was applied to maintain a low temperature at the bottom of the tower; [0018]).
Regarding claim 9, modified Park teaches the continuous process of claim 1, wherein the second stream comprises ~4% water (Table 1), which means that the concentration of the non-aqueous solvent in the first mixture was greater than or equal to a concentration required to do so. When modified by the teaching of ACS and Jacquet, the non-aqueous solvent will be tert-butanol, as analyzed above.
Furthermore, one of ordinary skill in the art would recognize that the more non-aqueous solvent (azeotropic agent) that is present the more water that can be carried away in the distillate (first stream), as these compounds travel together in the azeotrope.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to use an amount of tert-butanol as the azeotropic agent/non-aqueous solvent in the first mixture as required to dry the hydrogen peroxide to the desired extent, including into the range of 2% to 5 % water, as required by the instant claim.
Regarding claim 10, modified Park teaches the continuous process of claim 1 where the ratio of non-aqueous solvent (azeotropic agent) to water in the process is 9214:1468 (Table 1), or 6.3:1 , which is close to a ratio of 6:1 that would meet the limitations of the instant claim. Furthermore, one of ordinary skill in the art would recognize that the more non-aqueous solvent (azeotropic agent) that is present the more water that can be carried away in the distillate, though doing so would require more time, energy, and resource usage.
Therefore, it would have been obvious to one of ordinary skill in the art before the effective filing date of the claimed invention to optimize by routine experimentation the ratio of tert-butanol to water in the first mixture used in the method of modified Park, including to ratios of non-aqueous solvent to water recited in the instant claim. One of ordinary skill in the art would have been motivated to do so in order dry the hydrogen peroxide to the desired extent, while balancing costs of additional non-aqueous solvent and time and resources required to distill off more liquids.
It is also noted that the courts have found that “where 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.” In re Aller, 220 F.2d 454, 456, 105 USPQ 233, 235 (CCPA 1955). See MPEP 2144.05 II. Therefore, the claimed ratios of tert-butanol to water merely represent an obvious variant and/or routine optimization of the values of the cited prior art.
Conclusion
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/NICHOLAS A. PIRO/Assistant Examiner, Art Unit 1738
/PAUL A WARTALOWICZ/Primary Examiner, Art Unit 1735
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