Detailed Action
This is a Non-Final Office action based on application 18/279,989 filed on 1 September 2023. The application is a 371 of PCT/ US2022/ 018580, with priority to US provisional application 63/156,583 filed 4 March 2021.
Claims 1-9, 11-15, 18, 20, 21, and 23-25 are pending and have been fully considered.
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 .
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.
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 1, 5-7, 9, 11-15, 18, and 20-21 are rejected under 35 U.S.C. 103 as being unpatentable over Wu et al (CN 104119243 A ; hereinafter, text citations attributed to Wu are taken from a machine translation of the document into English), in view of Franczyk (US 5,292,936 A) and Koberstein et al (US 4,909,916 A). Evidentiary support in the rejection of claim 18 is provided by Chinchen (US 4,177,252 A).
Regarding claim 1, Wu teaches a process for preparing iminodiacetic acid (para [0002]), the process comprising:
introducing a feed salt stream comprising disodium iminodiacetic acid (DSIDA) into a salt compartment of a two-compartment electrodialysis bipolar membrane cell comprising the salt compartment and a base compartment (para [0014], “an aqueous solution of iminodiacetic acid disalt ... is fed into a bipolar membrane electrodialysis system”; para [0041] “membrane forms an alkaline chamber (III) ... and a salt chamber (IV) ... aqueous solution of disodium iminodiacetate is introduced into the salt chamber”; figure 1 illustrates the BPED with chambers as described);
recovering a salt product stream from the salt compartment of the two-compartment bipolar membrane cell, the salt product stream comprising iminodiacetic acid (IDA) and monosodium iminodiacetic acid (MSIDA) (para [0012], “pH is controlled at 3.0~4.0 in the salt chamber to obtain a mixed solution of iminodiacetic acid monosalt and iminodiacetic acid”; para [0041], “their yield is greater than 99 %”) ;
and recovering a base product stream from the base compartment of the two-compartment bipolar membrane cell, the base product stream comprising sodium hydroxide (para [0017], “alkaline solution obtained in the alkaline chamber”; para [0041], “mass fraction of sodium hydroxide in the alkaline chamber is 8.4%”);
contacting the salt product stream with a crystallizer, thereby forming a crystallizer stream (para [0042], “After acidification, crystallize at 40°C for 2 hours”);
contacting the crystallizer stream with a filtration system, thereby forming a solid product stream comprising iminodiacetic acid and a recirculation stream (para [0042], “Filter, wash ... and dry to obtain iminodiacetic acid product with a yield of 80% and a purity of 98%”);
and wherein at least a portion of the feed salt stream comprising DSIDA is prepared by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (para [0018]-[0019], [0040]).
Wu’s method differs from the claimed method in that Wu prepares at least a portion of the feed salt stream comprising DSIDA by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile. Wu teaches that the disodium iminodiacetic acid salt (DSIDA) can be prepared from a precursor of either iminodiacetonitrile or diethanolamine, however, market conditions in China favor the use of iminodiacetonitrile as the precursor (para [0005]). Wu does not disclose preparing at least a portion of DSIDA by reacting the base product stream with diethanolamine in the presence of a catalyst.
Franczyk teaches the synthesis of iminodiacetic acid disodium salt by reacting sodium hydroxide with diethanolamine in the presence of a copper catalyst (col 1 ln 5-11, col 4 ln 1-68, col 5 ln 1-48). Franczyk teaches iminodiacetic acid disodium is synthesized effectively and in 95% yield by this method (col 1 ln 62 – col 2 ln 5; col 4 ln 15-17).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu, by substituting Wu’s step of preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (Wu para [0018]-[0019], [0040]) with a step of instead preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with diethanolamine (DEA) in the presence of a catalyst, based on Franczyk’s teaching that the reaction of sodium hydroxide with diethanolamine in the presence of copper catalyst is an effective synthetic route to DSIDA (col 1 ln 5-11, col 1 ln 62-col 2 ln 5, col 4 ln 1-68, col 5 ln 1-48). The simple substitution of one known element for another (i.e., one known preparation of DSIDA in place of another known preparation) is likely to be obvious when predictable results are achieved (i.e., effective synthesis of DSIDA) [MPEP § 2143(B)]. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Wu also does not teach recovering, from the filtration system, a recirculation stream which is combined with the feed salt stream prior to introduction of the feed salt stream into the bipolar electrodialysis cell
Koberstein is similarly directed to a method of working up an amino acid by: introducing a feed stream into a diluent compartment of a three chamber electrodialysis device, the feed stream comprising the amino acid as well as the sodium salt of an unreacted starting material (figure 1-2, feed stream comprising amino acid “As” and salt “MX” is introduced into the central chamber of a three chamber ED or BPED device; col 4 ln 30-32; col 5 ln 35-38; col 6 ln 47-51);
recovering a base product stream from a base compartment of the electrodialysis cell, the base product stream comprising sodium hydroxide (figure 1-2, product of chamber 2 is MOH where M is the cation introduced by the salt MX; col 3 ln 33-39; per col 5 ln 34-41, M is sodium); wherein the base product stream is recirculated to an upstream reaction (col 3 ln 33-39; col 6 ln 16-17);
recovering a product stream from the diluent chamber electrodialysis cell, the product stream comprising the amino acid (col 3 ln 23-28; col 5 ln 46-57; col 6 ln 55-64);
contacting the product stream with a crystallizer, thereby forming a crystallizer stream, and separating the crystallizer stream into a solid product stream comprising the synthetic amino acid and a recirculation stream (col 6 ln 5-15);
wherein the recirculation stream is combined with the feed salt stream prior to introduction of the feed stream into the salt compartment of the electrodialysis cell (col 3 ln 28-33, “The mother liquor which remains after the separation of the L-amino acid which was crystallized out can be recycled and subjected together with fresh solution from the racemate resolution to electrodialysis again”; col 6 ln 12-15).
Koberstein teaches that the step of recycling of the recirculation stream, by combining it with the feed salt stream prior to the introduction of the feed stream into the electrodialysis device, is beneficial because it reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Wu by recycling the recirculation stream (i.e. the mother liquor remaining from Wu’s crystallization step) into the feed stream ahead of the feed stream’s introduction into the electrodialysis device, in light of Koberstein’s teaching that, when an amino acid is purified by electrodialysis followed by crystallization, and the crystallization mother liquor is recycled by combining it with the feed stream ahead of the feed stream’s introduction into the electrodialysis device, such recycling advantageously reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
Regarding claim 5, modified Wu renders the process of claim 1 obvious and Wu further teaches the salt compartment of the two-compartment bipolar membrane cell is bounded by a bipolar membrane and a cation exchange membrane and the base compartment of the two-compartment bipolar membrane is bounded by the cation exchange membrane bounding the salt compartment and a second bipolar membrane (figure 1, each of the salt compartments IV are bounded by a bipolar membrane “BP” and a cation exchange membrane “C”, and each of the base compartments III are bounded by a bipolar membrane “BP” and the cation exchange membrane “C” of an adjacent salt compartment).
Regarding claim 6, modified Wu renders the process of claim 1 obvious and Wu further teaches the two-compartment bipolar membrane cell further comprises an anode and a cathode (para [0041], “The bipolar membrane electrodialysis system has a cathode chamber (I) with a built-in cathode and an anode chamber (II) with a built-in anode”; see compartments I and II in figure 1).
Regarding claim 7, modified Wu renders obvious the process of claim 6, and Wu further teaches applying an electric potential between the cathode and the anode of the two compartment bipolar membrane cell, thereby inducing flow of cations from DSIDA in the salt compartment through the cation exchange membrane into the base compartment of the two-compartment bipolar membrane cell (para [0021], current is passed through the cathode and anode; figure 1, Na+ ions are transported from salt compartment IV through cation exchange membrane C to base compartment III).
Regarding claim 9, modified Wu renders obvious the process of claim 1, and Wu further teaches the concentration of DSIDA in the feed stream is 16.48% (para [0040]), which falls within the claimed range of at least about 5 wt%.
Regarding claims 11-13, modified Wu renders obvious the process of claim 1, and Wu further teaches the “monosodium iminodiacetate and iminodiacetate in the salt chamber are analyzed, and ... the mass fraction of iminodiacetate in the salt chamber is 18.5%” (para [0041]). This machine-translated phrasing admits of three possible interpretations:
- (a) the mass fraction of iminodiacetic acid is 18.5 wt%,
- (b) the mass fraction of monosodium iminodiacetate is 18.5 wt%, or
- (c) the combined mass fraction of both iminodiacetate species is 18.5 wt%.
Wu also teaches that the pH is 3.6 (para [0041]). According to the titration curve of iminodiacetic acid / monosodium iminodiacetate (disclosed by Applicant at instant figure 4), a mixture of these two species at pH 3.6 is about 25% free acid and 75% monosodium salt.
Therefore, with respect to claims 11 and 13:
- If Wu meant that (a) the salt product stream is 18.5 wt% iminodiacetic acid, then the iminodiacetic acid content of the salt product stream is about 18.5 wt% which falls within the claimed ranges of from 2 to 20 wt% (from claim 11) and less than about 30 wt% (from claim 13).
- If Wu meant that (b) the salt product stream is 18.5 wt% monosodium iminodiacetate, then the iminodiacetic acid content of the salt product stream is about 6.2 wt% which falls within the claimed ranges of from 2 to 20 wt% (from claim 11) and less than about 30 wt% (from claim 13).
- If Wu meant that (c) the iminodiacetic free acid and monosodium salt combined formed 18.5 wt% of the salt product stream, then the iminodiacetic free acid content of the salt product stream is about 4.6 wt% which falls within the claimed ranges of from 2 to 20 wt% (from claim 11) and less than about 30 wt% (from claim 13).
With respect to claim 12:
- If Wu meant that (a) the salt product stream is 18.5 wt% iminodiacetic acid, then the monosodium iminodiacetate content of the salt product stream is about 55.5 wt% which falls within the claimed range of at least about 5 wt%.
- If Wu meant that (b) the salt product stream is 18.5 wt% monosodium iminodiacetate, then the monosodium iminodiacetate content of the salt product stream is about 18.5 wt% which falls within the claimed range of at least about 5 wt%.
- If Wu meant that (c) the iminodiacetic free acid and monosodium salt combined formed 18.5 wt% of the salt product stream, then the iminodiacetic free acid content of the salt product stream is about 13.9 wt% which falls within the claimed range of at least 5 wt%.
Examiner believes (c) is the intended reading of Wu. However, regardless which one of (a), (b), and (c) is the accurate reading of the reference, Wu’s disclosure satisfies the limitations of claims 11, 12 and 13.
Regarding claim 14, modified Wu renders obvious the process of claim 1, and Wu further teaches that the solids that are filtered out after crystallizing (i.e. the solid product stream) comprise iminodiacetic acid at a purity of 98%, which falls within the claimed range of at least about 10%.
Regarding claim 15, Wu, Franczyk, and Koberstein render obvious the process of claim 1, and Franczyk further teaches preparing the DSIDA by reacting the base product stream comprising sodium hydroxide with diethanolamine (DEA) in the presence of a catalyst comprises dehydrogenation of diethanolamine (col 4 ln 5-18, diethanolamine is converted to iminodiacetic acid with liberation of hydrogen gas), wherein the dehydrogenation reaction comprises a strong base (col 4 ln 7-8, “a 50% aqueous solution of sodium hydroxide”) and a catalyst (col 4 ln 8-9, “a Raney copper catalyst”).
Regarding claim 18, Wu, Franczyk, and Koberstein render obvious the process of claim 1, and Franczyk further teaches preparing the DSIDA by reacting the base product stream comprising sodium hydroxide with diethanolamine (DEA) in the presence of a catalyst comprises catalytic oxidation of diethanolamine (col 4 ln 5-18, diethanolamine is converted to iminodiacetic acid; this is a catalytic oxidation reaction because it is the conversion of a primary alcohol to the corresponding carboxylate (an oxidation reaction) and it relies on a catalyst), wherein the catalyst is susceptible to poisoning or deactivation by chloride (according to instant specification para [0078], any catalyst useful for such a purpose is generally susceptible to poisoning or deactivation by chloride; it is also known in the art that metallic copper catalysts in particular are susceptible to chloride poisoning (see e.g. Chinchen at col 1 ln 8-54); therefore Franczyk’s catalyst, being metallic copper, inherently possesses the property of being susceptible to poisoning or deactivation by chloride).
Regarding claim 20, modified Wu renders obvious the process of claim 1, and Wu further teaches the base product stream comprises 8.4 % NaOH (para [0041]), which falls within the claimed range of at least about 5 wt.% of a base.
Regarding claim 21, modified Wu renders obvious the process of claim 1, and Wu further teaches the solid product stream is further processed by drying to form an iminodiacetic acid wetcake (para [0042], after filtering, the crystals are washed and dried).
Claims 2 and 25 are rejected under 35 U.S.C. 103 as being unpatentable over Wu, in view of Koberstein and further in view of Jones et al (US 5,527,953 A).
Regarding claim 2, Wu teaches a process for preparing iminodiacetic acid (para [0002]), the process comprising:
introducing a feed salt stream comprising disodium iminodiacetic acid (DSIDA) into a salt compartment of a two-compartment electrodialysis bipolar membrane cell comprising the salt compartment and a base compartment (para [0014], “an aqueous solution of iminodiacetic acid disalt ... is fed into a bipolar membrane electrodialysis system”; para [0041] “membrane forms an alkaline chamber (III) ... and a salt chamber (IV) ... aqueous solution of disodium iminodiacetate is introduced into the salt chamber”; figure 1 illustrates the BPED with chambers as described);
recovering a salt product stream from the salt compartment of the two-compartment bipolar membrane cell, the salt product stream comprising iminodiacetic acid (IDA) and monosodium iminodiacetic acid (MSIDA) (para [0012], “pH is controlled at 3.0~4.0 in the salt chamber to obtain a mixed solution of iminodiacetic acid monosalt and iminodiacetic acid”; para [0041], “their yield is greater than 99 %”) ;
and recovering a base product stream from the base compartment of the two-compartment bipolar membrane cell, the base product stream comprising sodium hydroxide (para [0017], “alkaline solution obtained in the alkaline chamber”; para [0041], “mass fraction of sodium hydroxide in the alkaline chamber is 8.4%”);
contacting the salt product stream with a crystallizer, thereby forming a crystallizer stream (para [0042], “After acidification, crystallize at 40°C for 2 hours”) ;
contacting the crystallizer stream with a filtration system, thereby forming a solid product stream comprising iminodiacetic acid and a recirculation stream (para [0042], “Filter, wash ... and dry to obtain iminodiacetic acid product with a yield of 80% and a purity of 98%”).
Wu also teaches that iminodiacetic acid is used as an intermediate in the synthesis of pesticides such as glyphosate (para [0004]).
Wu does not teach recovering, from the filtration system, a recirculation stream which is combined with the feed salt stream prior to introduction of the feed salt stream into the bipolar electrodialysis cell.
Koberstein is similarly directed to a method of working up an amino acid by:
introducing a feed stream into a diluent compartment of a three chamber electrodialysis device, the feed stream comprising the amino acid as well as the sodium salt of an unreacted starting material (figure 1-2, feed stream comprising amino acid “As” and salt “MX” is introduced into the central chamber of a three chamber ED or BPED device; col 4 ln 30-32; col 5 ln 35-38; col 6 ln 47-51);
recovering a base product stream from a base compartment of the electrodialysis cell, the base product stream comprising sodium hydroxide (figure 1-2, product of chamber 2 is MOH where M is the cation introduced by the salt MX; col 3 ln 33-39; per col 5 ln 34-41, M is sodium); wherein the base product stream is recirculated to an upstream reaction (col 3 ln 33-39; col 6 ln 16-17);
recovering a product stream from the diluent chamber electrodialysis cell, the product stream comprising the amino acid (col 3 ln 23-28; col 5 ln 46-57; col 6 ln 55-64);
contacting the product stream with a crystallizer, thereby forming a crystallizer stream, and separating the crystallizer stream into a solid product stream comprising the synthetic amino acid and a recirculation stream (col 6 ln 5-15);
wherein the recirculation stream is combined with the feed salt stream prior to introduction of the feed stream into the salt compartment of the electrodialysis cell (col 3 ln 28-33, “The mother liquor which remains after the separation of the L-amino acid which was crystallized out can be recycled and subjected together with fresh solution from the racemate resolution to electrodialysis again”; col 6 ln 12-15).
Koberstein teaches that the step of recycling of the recirculation stream, by combining it with the feed salt stream prior to the introduction of the feed stream into the electrodialysis device, is beneficial because it reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Wu by recycling the recirculation stream (i.e. the mother liquor remaining from Wu’s crystallization step) into the feed stream ahead of the feed stream’s introduction into the electrodialysis device, in light of Koberstein’s teaching that, when an amino acid is purified by electrodialysis followed by crystallization, and the crystallization mother liquor is recycled by combining it with the feed stream ahead of the feed stream’s introduction into the electrodialysis device, such recycling advantageously reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
Wu does not teach wherein the process further comprises phosphonomethylating the IDA in the solid product stream.
Jones teaches phosphonomethylating iminodiacetic acid to yield N-phosphonomethyliminodiacetic acid (col 1 ln 44-59). Particularly Jones teaches that their method benefits from the provision of iminodiacetic acid in its acid form, rather than as its alkali salt form (col 1 ln 37-43, col 2 ln 3-6). Jones teaches that the preparation of N-phosphonomethyliminodiacetic acid is useful because this compound is an intermediate in the manufacture of the herbicide N-phosphonomethylglycine (col 1 ln 10-13) also known as glyphosate.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu’s method of purifying iminodiacetic acid, by appending to Wu’s method, a step of phosphonomethylating the iminodiacetic acid to form N-phosphonomethyliminodiacetic acid, as taught in Jones, based on Jones’ teaching that N-phosphonomethyliminodiacetic acid is a compound that is useful as a precursor to the industrially important herbicide N-phosphonomethylglycine (col 1 ln 10-13).
Regarding claim 25, Wu in view of Koberstein and Jones renders obvious the process of claim 2, and Jones further teaches phosphonomethylating the iminodacetic acid in the solid product stream forms N-(phosphonomethyl)iminodiacetic acid (PMIDA) (col 1 ln 44 - col 2 ln 2). Jones teaches that the PMIDA is useful in a process for preparing N-(phosphonomethyl)glycine (glyphosate) (col 1 ln 10-13).
Wu, Koberstein, Jones do not disclose a specific process for preparing glyphosate.
However, it would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to use the PMIDA, prepared by the method of Wu, Koberstein, and Jones, in a process for preparing glyphosate, based on Jones’s teaching that PMIDA is useful in a process for preparing glyphosate (col 1 ln 10-13).
Claim 3 is rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Franczyk, Koberstein, and Jones.
Regarding claim 3, Wu teaches a process for preparing iminodiacetic acid (para [0002]), the process comprising:
introducing a feed salt stream comprising disodium iminodiacetic acid (DSIDA) into a salt compartment of a two-compartment electrodialysis bipolar membrane cell comprising the salt compartment and a base compartment (para [0014], “an aqueous solution of iminodiacetic acid disalt ... is fed into a bipolar membrane electrodialysis system”; para [0041] “membrane forms an alkaline chamber (III) ... and a salt chamber (IV) ... aqueous solution of disodium iminodiacetate is introduced into the salt chamber”; figure 1 illustrates the BPED with chambers as described);
recovering a salt product stream from the salt compartment of the two-compartment bipolar membrane cell, the salt product stream comprising iminodiacetic acid (IDA) and monosodium iminodiacetic acid (MSIDA) (para [0012], “pH is controlled at 3.0~4.0 in the salt chamber to obtain a mixed solution of iminodiacetic acid monosalt and iminodiacetic acid”; para [0041], “their yield is greater than 99 %”) ;
and recovering a base product stream from the base compartment of the two-compartment bipolar membrane cell, the base product stream comprising sodium hydroxide (para [0017], “alkaline solution obtained in the alkaline chamber”; para [0041], “mass fraction of sodium hydroxide in the alkaline chamber is 8.4%”);
contacting the salt product stream with a crystallizer, thereby forming a crystallizer stream (para [0042], “After acidification, crystallize at 40°C for 2 hours”) ;
contacting the crystallizer stream with a filtration system, thereby forming a solid product stream comprising iminodiacetic acid and a recirculation stream (para [0042], “Filter, wash ... and dry to obtain iminodiacetic acid product with a yield of 80% and a purity of 98%”)
and wherein at least a portion of the feed salt stream comprising DSIDA is prepared by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (para [0018]-[0019], [0040]).
Wu also teaches that iminodiacetic acid is used as an intermediate in the synthesis of pesticides such as glyphosate (para [0004]).
Wu’s method differs from the claimed method in that Wu prepares at least a portion of the feed salt stream comprising DSIDA by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile. Wu teaches that the disodium iminodiacetic acid salt (DSIDA) can be prepared from a precursor of either iminodiacetonitrile or diethanolamine, however, market conditions in China at the time of Wu’s invention favored the use of iminodiacetonitrile as the precursor (para [0005]). Wu does not disclose preparing at least a portion of DSIDA by reacting the base product stream with diethanolamine in the presence of a catalyst.
Franczyk teaches the synthesis of iminodiacetic acid disodium salt by reacting sodium hydroxide with diethanolamine in the presence of a copper catalyst (col 1 ln 5-11, col 4 ln 1-68, col 5 ln 1-48). Franczyk teaches iminodiacetic acid disodium is synthesized effectively and in 95% yield by this method (col 1 ln 62 – col 2 ln 5; col 4 ln 15-17).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu, by substituting Wu’s step of preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (Wu para [0018]-[0019], [0040]) with a step of instead preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with diethanolamine (DEA) in the presence of a catalyst, based on Franczyk’s teaching that the reaction of sodium hydroxide with diethanolamine in the presence of copper catalyst is an effective synthetic route to DSIDA (col 1 ln 5-11, col 1 ln 62-col 2 ln 5, col 4 ln 1-68, col 5 ln 1-48). The simple substitution of one known element for another (i.e., one known preparation of DSIDA in place of another known preparation) is likely to be obvious when predictable results are achieved (i.e., effective synthesis of DSIDA) [MPEP § 2143(B)]. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Wu does not teach recovering, from the filtration system, a recirculation stream which is combined with the feed salt stream prior to introduction of the feed salt stream into the bipolar electrodialysis cell.
Koberstein is similarly directed to a method of working up an amino acid by:
introducing a feed stream into a diluent compartment of a three chamber electrodialysis device, the feed stream comprising the amino acid as well as the sodium salt of an unreacted starting material (figure 1-2, feed stream comprising amino acid “As” and salt “MX” is introduced into the central chamber of a three chamber ED or BPED device; col 4 ln 30-32; col 5 ln 35-38; col 6 ln 47-51);
recovering a base product stream from a base compartment of the electrodialysis cell, the base product stream comprising sodium hydroxide (figure 1-2, product of chamber 2 is MOH where M is the cation introduced by the salt MX; col 3 ln 33-39; per col 5 ln 34-41, M is sodium); wherein the base product stream is recirculated to an upstream reaction (col 3 ln 33-39; col 6 ln 16-17);
recovering a product stream from the diluent chamber electrodialysis cell, the product stream comprising the amino acid (col 3 ln 23-28; col 5 ln 46-57; col 6 ln 55-64);
contacting the product stream with a crystallizer, thereby forming a crystallizer stream, and separating the crystallizer stream into a solid product stream comprising the synthetic amino acid and a recirculation stream (col 6 ln 5-15);
wherein the recirculation stream is combined with the feed salt stream prior to introduction of the feed stream into the salt compartment of the electrodialysis cell (col 3 ln 28-33, “The mother liquor which remains after the separation of the L-amino acid which was crystallized out can be recycled and subjected together with fresh solution from the racemate resolution to electrodialysis again”; col 6 ln 12-15).
Koberstein teaches that the step of recycling of the recirculation stream, by combining it with the feed salt stream prior to the introduction of the feed stream into the electrodialysis device, is beneficial because it reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify the method of Wu by recycling the recirculation stream (i.e. the mother liquor remaining from Wu’s crystallization step) into the feed stream ahead of the feed stream’s introduction into the electrodialysis device, in light of Koberstein’s teaching that, when an amino acid is purified by electrodialysis followed by crystallization, and the crystallization mother liquor is recycled by combining it with the feed stream ahead of the feed stream’s introduction into the electrodialysis device, such recycling advantageously reduces material loss and decreases the amount of wastewater which must be disposed of (col 3 ln 28-33, 51-59).
Wu also does not teach wherein the process further comprises phosphonomethylating the IDA in the solid product stream.
Jones teaches phosphonomethylating iminodiacetic acid to yield N-phosphonomethyliminodiacetic acid (col 1 ln 44-59). Particularly Jones teaches that their method benefits from the provision of iminodiacetic acid in its acid form, rather than as its alkali salt form (col 1 ln 37-43, col 2 ln 3-6). Jones teaches that the preparation of N-phosphonomethyliminodiacetic acid is useful because this compound is an intermediate in the manufacture of the herbicide N-phosphonomethylglycine (col 1 ln 10-13), also known as glyphosate.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu’s method of purifying iminodiacetic acid, by appending to Wu’s method, a step of phosphonomethylating the iminodiacetic acid to form N-phosphonomethyliminodiacetic acid, as taught in Jones, based on Jones’ teaching that N-phosphonomethyliminodiacetic acid is a compound that is useful as a precursor to the herbicide N-phosphonomethylglycine (col 1 ln 10-13).
Claim 23 is rejected under 35 U.S.C. 103 as being unpatentable over Wu, Franczyk, and Koberstein, as applied to claim 21 above, in further view of Jones.
Regarding claim 23, Wu in view of Franczyk and Koberstein renders the process of claim 21 obvious. Wu, Franczyk, and Koberstein do not teach the iminodiacetic acid wetcake is used in a process for preparing N-(phosphonomethyl)iminodiacetic acid (PMIDA).
Jones teaches using iminodiacetic acid in a process for preparing N-(phosphonomethyl)iminodiacetic acid (PMIDA) (col 1 ln 44-59). Particularly Jones teaches that their method benefits from the provision of iminodiacetic acid in its acid form, rather than as its alkali salt form (col 1 ln 37-43, col 2 ln 3-6). Jones teaches that the preparation of N-phosphonomethyliminodiacetic acid is useful because this compound is an intermediate in the manufacture of the herbicide N-phosphonomethylglycine (col 1 ln 10-13), also known as glyphosate.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu’s method of purifying iminodiacetic acid, by appending to Wu’s method a step of phosphonomethylating the iminodiacetic acid to form N-phosphonomethyliminodiacetic acid, as taught in Jones, based on Jones’ teaching that N-phosphonomethyliminodiacetic acid is a compound that has industrial utility as a precursor to the herbicide N-phosphonomethylglycine (col 1 ln 10-13).
Claim 4 is rejected under 35 U.S.C. 103 as being unpatentable over Wu in view of Franczyk.
Regarding claim 4, Wu teaches a process for preparing iminodiacetic acid (para [0002]), the process comprising:
introducing a feed salt stream comprising disodium iminodiacetic acid (DSIDA) into a salt compartment of a two-compartment electrodialysis bipolar membrane cell comprising the salt compartment and a base compartment (para [0014], “an aqueous solution of iminodiacetic acid disalt ... is fed into a bipolar membrane electrodialysis system”; para [0041] “membrane forms an alkaline chamber (III) ... and a salt chamber (IV) ... aqueous solution of disodium iminodiacetate is introduced into the salt chamber”; figure 1 illustrates the BPED with chambers as described);
recovering a salt product stream from the salt compartment of the two-compartment bipolar membrane cell, the salt product stream comprising iminodiacetic acid (IDA) and monosodium iminodiacetic acid (MSIDA) (para [0012], “pH is controlled at 3.0~4.0 in the salt chamber to obtain a mixed solution of iminodiacetic acid monosalt and iminodiacetic acid”; para [0041], “their yield is greater than 99 %”) ;
and recovering a base product stream from the base compartment of the two-compartment bipolar membrane cell, the base product stream comprising sodium hydroxide (para [0017], “alkaline solution obtained in the alkaline chamber”; para [0041], “mass fraction of sodium hydroxide in the alkaline chamber is 8.4%”);
contacting the salt product stream with a crystallizer, thereby forming a crystallizer stream (para [0042], “After acidification, crystallize at 40°C for 2 hours”) ;
contacting the crystallizer stream with a filtration system, thereby forming a solid product stream comprising iminodiacetic acid and a recirculation stream (para [0042], “Filter, wash ... and dry to obtain iminodiacetic acid product with a yield of 80% and a purity of 98%”);
wherein the base product stream is essentially chloride (Cl-) free (para [0038]-[0042], the only disclosed constituents of the base stream are sodium hydroxide and water, and no chlorine-containing species is introduced at any point of Wu’s method).
and wherein at least a portion of the feed salt stream comprising DSIDA is prepared by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (para [0018]-[0019], [0040]).
Wu’s method differs from the claimed method in that Wu prepares at least a portion of the feed salt stream comprising DSIDA by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile. Wu teaches that the disodium iminodiacetic acid salt (DSIDA) can be prepared from a precursor of either iminodiacetonitrile or diethanolamine, however, market conditions in China at the time of Wu’s invention favored the use of iminodiacetonitrile as the precursor (para [0005]). Wu does not disclose preparing at least a portion of DSIDA by reacting the base product stream with diethanolamine in the presence of a catalyst.
Franczyk teaches the synthesis of iminodiacetic acid disodium salt by reacting sodium hydroxide with diethanolamine in the presence of a copper catalyst (col 1 ln 5-11, col 4 ln 1-68, col 5 ln 1-48). Franczyk teaches iminodiacetic acid disodium is synthesized effectively and in 95% yield by this method (col 1 ln 62 – col 2 ln 5; col 4 ln 15-17).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu, by substituting Wu’s step of preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with iminodiacetonitrile (Wu para [0018]-[0019], [0040]) with a step of instead preparing disodium iminodiacetate (DSIDA) by reacting the base product stream comprising sodium hydroxide with diethanolamine (DEA) in the presence of a catalyst, based on Franczyk’s teaching that the reaction of sodium hydroxide with diethanolamine in the presence of copper catalyst is an effective synthetic route to DSIDA (col 1 ln 5-11, col 1 ln 62-col 2 ln 5, col 4 ln 1-68, col 5 ln 1-48). The simple substitution of one known element for another (i.e., one known preparation of DSIDA in place of another known preparation) is likely to be obvious when predictable results are achieved (i.e., effective synthesis of DSIDA) [MPEP § 2143(B)]. The selection of a known material, which is based upon its suitability for the intended use, is within the ambit of one of ordinary skill in the art [MPEP § 2144.07].
Claims 8 and 24 are rejected under 35 U.S.C. 103 as being unpatentable over modified Wu as applied to claim 1 above, in further view of Casanova et al (WO 2019/236814 A1).
Regarding claim 8, modified Wu renders the process of claim 1 obvious, but is silent with respect to the current efficiency of the electrodialysis cell.
Casanova is similarly directed to a bipolar electrodialysis method for of converting disodium imidodiacetate to imidodiacetic acid (para [0108]-[0115]). Casanova teaches that it is desirable for the method to have a sufficiently high current efficiency (para [0003]-[0005], [0041]), and that by selection of suitable reaction conditions, they achieve a current density based on the transport of the DSIDA cation to the base compartment in the range of 85 to 99% (para [0094], “from about 85% to about 99%”; pg 29 Table 4, the current efficiencies based on Na+ transport for examples 1, 2, and 3 respectively were 90%, 89%, and 89%; para [0146], “current efficiency of this experiment was 87%”), which falls within the claimed range of at least about 80%.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu by operating the bipolar electrodialysis cell at a current efficiency of at least about 80%, based on Casanova’s teaching that the bipolar electrodialysis of disodium iminodiacetate can be operated at current efficiencies of from 85% to 99% (para [0094], [0146], pg 29 Table 4) and that it is desirable to do so (para [0003]-[0005]).
Regarding claim 24, modified Wu renders obvious the process of claim 1 wherein the base product stream comprises NaOH. Wu is silent with respect to the specific power usage of the electrodialysis cell.
Casanova is similarly directed to a bipolar electrodialysis method for of converting disodium imidodiacetate to imidodiacetic acid (para [0108]-[0115]) with concomitant production of a base product stream comprising NaOH (para [0086], [0104], [0117]). Casanova teaches that by selection of suitable reaction conditions, they achieve a specific power usage of 0.084, 0.090, or 0.094 kWh/mol NaOH (Examples 1, 2, and 3 respectively, as disclosed at pg 29 Table 4), which falls within the claimed range of less than about 3000 kWh per Ton base ((0.084 kWh/mol NaOH) * (40 g / mol)-1 * (0.907 * 106 g/Ton = 1900 kWh / Ton; likewise, 0.090 kWh/mol NaOH = 2040 kWh / Ton; likewise, 0.094 kWh/mol NaOH = 2130 kWh/Ton) current density based on the transport of the DSIDA cation to the base compartment in the range of 85 to 99% (para [0094], “from about 85% to about 99%”; pg 29 Table 4, the current efficiencies based on Na+ transport for examples 1, 2, and 3 respectively were 90%, 89%, and 89%; para [0146], “current efficiency of this experiment was 87%”), which falls within the claimed range of at least about 80%.
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to modify Wu by operating the bipolar electrodialysis cell at a specific power usage of less than 3000 kWh/Ton base, based on Casanova’s teaching of that the bipolar electrodialysis of disodium iminodiacetate can be operated at specific power usage of 0.084-0.094 kWh/mol NaOH = 1900-2130 kWh/Ton NaOH. An obvious motivation for operating Wu’s method at a power usage of 3000 kWh/Ton base or less would have been to minimize power usage.
Conclusion
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/ANDREW KOLTONOW/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795
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