Detailed Action
This is a Final Office action based on application 18/408,873 filed on January 10, 2024. The application is a Continuation-In-Part of application 18/369,838, with priority to provisional application 63/438,519 filed January 11, 2023.
Claims 1-36 are pending, claims 20-24 are currently withdrawn, and claims 1-19 and 25-36 have been fully considered.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 .
Status of the Rejection
The §112(b) rejection is withdrawn in response to amendment.
The §103 rejections of record are maintained.
Claim Rejections - 35 USC § 103
The text of those sections of Title 35, U.S. Code not included in this action can be found in a prior Office action.
Claims 1-10, 13-17, 19, 25-29, and 33-36 are rejected under 35 U.S.C. 103 as being unpatentable over “Overa” (Overa et al, “Enhancing acetate selectivity by coupling anodic oxidation to carbon monoxide electroreduction”, Nature Catalysis, vol 5, pg 738-745 (2022)) in view of “Kaczur 2013” (US 2013/0180863 A1 to Kaczur et al).
Regarding claim 1, Overa teaches a method comprising:
supplying a volume of carbon monoxide to a cathode area of a carbon monoxide electrolyzer to be used as a reduction substrate (pg 738, “Here, we report a CO electrolyser”; pg 739 figure 1a and caption, “reduction of CO on the Cu catalyst surface (cathode)”; pg 744 left column para 5, “Carbon monoxide gas was fed to the cathode end plate using a mass flow controller”);
generating a volume of an organic anion, in an anode area of the carbon monoxide electrolyzer, using the reduction substrate (per pg 739 figure 1a, and pg 739 left column para 1 – pg 740 left column para 2, carbon monoxide is reduced at the cathode to a mix of intermediate products including ethanol, the intermediates are transferred to the anode compartment, and the intermediates are then oxidized at the anode to form acetate and propionate ions; thus, the reduction substrate that was supplied to the cathode (carbon monoxide) is used to generate a volume of organic anion (acetate) in the anode area of the electrolyzer);
obtaining a liquid stream from the anode area of the carbon monoxide electrolyzer, wherein the liquid stream includes the volume of the organic anion and a volume of a base (pg 739 right column para 1, “electrolyser is designed to produce a concentrated liquid product stream in the anode chamber”; pg 739 figure 1d, anolyte concentration is maintained at a KOH concentration of from 1M to 9 M, i.e. the liquid stream obtained from the anode area includes a volume of base);
recycling a volume of the base to the anode area of the carbon monoxide electrolyzer to maintain a strongly alkaline anolyte in the anode area (pg 740 left column para 2, a three molar KOH solution was continually circulated through the anode area to maintain a strongly alkaline anolyte in the anode area; pg 739 figure 1d and pg 740 right column para 2, Overa varied the KOH concentration of anolyte and observed that product concentration and purity improved with increasing alkalinity up to a KOH concentration of 7 M).
Overa also contemplates combining their carbon monoxide electrolysis process with a separation and solvent/base recycle process, to produce a first stream comprising the organic anion product and a second stream comprising the potassium hydroxide recycle (discussed at pg 743 left column para 1, and illustrated in Supplementary information, pg 22, Supplementary figure 25).
However, Overa does not disclose a separation process characterized in that (i) the separation process uses a membrane for a membrane separation process; (ii) the separation process separates a volume of a cation from the liquid stream; (iii) the first stream includes a second volume of the base; (iv) the second stream includes a volume of an organic acid; (v) the volume of the organic acid includes the volume of the organic anion; and (vi) the second volume of the base includes the volume of the cation.
Kaczur 2013 is directed to a method of electrolytically reducing CO2 to formate (an organic anion), comprising:
- supplying a volume of CO2 to a cathode area of an oxocarbon electrolyzer to be used as a reduction substrate (figure 1 and para [0039], CO2 is supplied to the cathode area 110 of electrolyzer 102, where the CO2 is used a reduction substrate);
- generating a volume of an organic anion using the reduction substrate (figure 1 and para [0039], CO2 is reduced at the cathode to generate the organic anion formate);
- obtaining a liquid stream from the oxocarbon electrolyzer, wherein the liquid stream includes the volume of the organic anion and a volume of a base (figure 1 and para [0039]-[0040], cathode output 146 is sent to gas-liquid separator 150 which outputs a liquid product stream 154 which includes the organic anion (formate) and may also contain hydroxide (a base); para [0040]-[0041] pH of the product stream is monitored by pH sensor 148b, and additional base can be metered in to maintain desired pH level); and
- generating, using a separation process and from the liquid stream, a first stream and a second stream, whereby the first stream and the second stream are separate (figure 2 and para [0042]-[0046], "electrochemical acidification system 200" separates the cathode product stream into a first stream 246 comprising base, and a second stream (referred to as #260 in the text but #230 in the figure) comprising formic acid; figure 3 shows how electrolyzer unit 100 is connected to separation system 200),
wherein:
- (i) the separation process uses a membrane for a membrane separation process (figure 6 and para [0078], the separation system includes a membrane nanofiltration unit, located between the electrolysis unit and the acidification unit);
- (ii) the separation process separates a volume of a cation from the liquid stream (see figures 2 and 4, and para [0043]: the alkali cation from the alkali formate liquid stream is separated by drawing the cation across cation exchange membrane 214b into stream 246);
- (iii) the first stream includes a second volume of the base (figure 3, potassium hydroxide recycle loop 302 corresponds to claimed second volume of the base; para [0046]-[0047], [0078]);
- (iv) the second stream includes a volume of an organic acid (para [0043], "product stream 260 including an organic acid product, preferably formic acid");
- (v) the volume of the organic acid includes the volume of the organic anion (para [0042] and figures 2 and 4, the organic acid product stream is the conjugate acid formed by protonating the organic anion); and
- (vi) the second volume of the base includes the volume of the cation (para [0042]-[0046], alkali cations drawn from the liquid stream 154, across membrane 214b, into the first stream 246, combine with hydroxide ions in cathode chamber 210 to form the alkali hydroxide base in the first stream 246, which subsequently becomes part of the second volume of base 302); and
recycling a volume of base from the separation process to the electrolyzer (para [0046]-[0048], figure 3, showing the KOH / KHCO3 base stream from separation stage 200 is recycled via recycle loop 302 to electrolysis stage 100).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to incorporate, into Oveda’s method, the separation process disclosed by Kaczur 2013, because Oveda is directed to an electrolysis process forming a product stream comprising an organic anion (acetate) in aqueous base, and is motivated to combine it with a separation process for separating the anion from the base (pg 743 left column para 1, and illustrated in Supplementary information, pg 22, Supplementary figure 25); and Kaczur 2013, who is similarly directed to an electrolysis process that yields a liquid product stream, separates it into an organic anion product and an aqueous base, and recycles the base to the electrolyzer, teaches a nanofiltration and electrodialysis process which is effective to this end. The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 2, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Kaczur 2013 further teaches:
the separation process includes the membrane separation process and an acid-base separation process (separation process includes membrane nanofiltration process as described in figure 6 and para [0078], and acid-base separation process described in figure 2 and para [0042]-[0046]);
the membrane separation process generates a concentrated salt solution and separates a first portion of the base (para [0078] and figure 6, nanofiltration process generates a permeate solution of organic anion salt (formate salt) and a reject stream concentrated in potassium carbonate salt (a first portion of base); para [0158]-[0160], the nanofiltration gives a negative rejection percentage for formate, meaning the permeate solution has a higher formate concentration than the feed and therefore reads on a concentrated salt solution; para [0078], potassium hydroxide is mixed into the liquid stream immediately before membrane separation, and more potassium hydroxide is mixed into the reject stream after membrane separation, therefore the reject stream is a first portion);
the acid-base separation process generates the volume of the organic acid and a second portion of the base (para [0078], the concentrated salt stream from the membrane separation process is passed in to the acid-base separation process of figure 2; para [0042]-[0046], the acid-base separation generates H+ which displaces alkali cations from the concentrated alkali formate to form the corresponding organic acid (formic acid), and the alkali ions pass through cation exchange membrane 214b to compartment 210 where water reduction is taking place, thereby generating an alkali hydroxide solution); and
the first and second portions of base comprise the same base (the first portion of base corresponds to the reject stream derived from membrane separation; per para [0078], potassium hydroxide is mixed into the liquid stream immediately before membrane separation, and more potassium hydroxide is mixed into the reject stream after membrane separation, so that the first portion of base comprises both potassium hydroxide and potassium carbonate; para [0043], [0046], the second portion of base comprises potassium hydroxide; therefore both portions comprise the same base (potassium hydroxide)), and are combined to form the second volume of base (figure 3; para [0047], the second portion of base is directed to base recycle loop at figure 3 block 302; para [0078], the base reject stream from the membrane filtration (ie the first portion of base) is also recirculated to the block 302 of figure 3)).
Regarding claim 3, Overa in view of Kaczur 2013 renders the method of claim 2 obvious. Kaczur 2013 further teaches the acid-base separation process includes an electrodialysis process (figure 2, para [0043]-[0044]; figure 4, para [0075]).
Regarding claim 4, Overa in view of Kaczur 2013 renders the method of claim 2 obvious. Kaczur 2013 further teaches the acid-base separation process uses a bipolar membrane electrodialysis process (figure 4, para [0075]).
Regarding claim 5, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Kaczur 2013 further teaches: the acid-base separation process uses an acid-base generation process (para [0042], the acid-base separation process generates an acid and a base); the membrane separation process and the acid-base generation process generate the second volume of the base (the first portion of base (base reject stream from nanofiltration process as disclosed in para [0078]) and the second portion of base (alkaline catholyte stream from the acid-base separation process, [0042]-[0047]) are combined at the base recycle loop 302 (figure 3) to form second volume of base that is then recycled to the electrolyzer 100), and the acid-base separation process uses an organic acid removal system, which generates the second stream (figure 3, separator 200 produces a mixed stream of formic acid, potassium formate solution, and CO2, which are separated into three streams at 304d; para [0047]-[0048], organic acid removal "may include evaporation, distillation, or another suitable physical separation/concentration process", note that distillation is within the scope of "organic acid removal system" per instant specification para [0059]).
Regarding claim 6, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Kaczur 2013 further teaches the separation process comprises:
- applying the liquid stream to the membrane to produce a concentrated organic salt solution (para [0078] and figure 6, liquid stream is applied to nano-filtration membrane to produce potassium formate permeate stream; para [0158]-[0160], the nanofiltration gives a negative rejection percentage for formate, meaning the permeate has a higher formate concentration than the feed);
- acidifying the concentrated organic salt solution with a volume of generated acid to produce a volume of an organic acid and alkali metal salt solution (para [0078], potassium formate permeate stream is sent to "electrochemical acidification system 200"; figure 2, figure 4, and para [0042]-[0046], "electrochemical acidification system 200" generates hydrogen ions, which displace potassium ions in the potassium formate solution to produce formic acid (organic acid) while the displaced alkali metal ion combines with a hydroxide ion to form potassium hydroxide);
- removing the volume of the organic acid from the volume of organic acid and metal salt solution to produce a volume of a metal salt solution and the second stream (figure 2, para [0042]-[0046], the organic acid and the metal hydroxide salt solution are separated into first stream 246 comprising metal hydroxide, and a second stream (referred to as #260 in the text but #230 in the figure) comprising the organic acid); and
- applying the volume of the metal salt solution to an acid-base generator (figure 2, metal salt stream 246 is recirculated back to the acid base generator 202); wherein the acid-base generator generates the volume of generated acid prior to the acidifying step (figure 2 and para [0043], acid-based generator 202 first generates acid in anode compartment 208, and then migrates that acid across CEM 214a to central compartment 212 where the acidifying step takes place) and uses the volume of the metal salt solution to generate more of the generated acid (figure 2 and para [0046], the metal salt solution is recirculated back into electrochemical acid base generator 202 system for further acid generation).
Regarding claim 7, Overa in view of Kaczur 2013 renders the method of claim 6 obvious. Kaczur 2013 further teaches recirculating the first stream to their oxocarbon electrolyzer to maintain at least one of a pH and a conductivity of an electrolyte of the oxocarbon electrolyzer (figure 3 and para [0047], the base stream (first stream) from separation system 200 is recycled via recycle loop 302 to provide bicarbonate (base) to the electrolyzer 100; para [0039]-[0041], bicarbonate is metered into the catholyte of electrolyzer 100 for the purpose of maintaining desired pH); wherein the acid-base generator and the membrane separation process generate the first stream (figure 3 and para [0042]-[0048], electrochemical acidification system 200 generates the base stream (first stream); para [0078], the nanofiltration process generates additional base which is merged into the base stream that is recirculated to the electrolyzer). Applied to the base method of Overa, this would correspond to recirculating the first stream to Overa’s CO electrolyzer as claimed.
Regarding claim 8, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Kaczur 2013 further teaches the acid-base generator uses an electrodialysis process (figure 2, para [0043]-[0044]; figure 4, para [0075]).
Regarding claim 9, Overa in view of Kaczur 2013 renders the method of claim 6 obvious. Kaczur 2013 further teaches the acid-base generator uses a bipolar membrane electrodialysis electrolyzer (figure 4, para [0075]).
Regarding claim 10, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Kaczur 2013 further teaches the separation process comprises:
- supplying the liquid stream to a separating area of an electrodialysis electrolyzer (figure 2, liquid stream 154 is supplied to area 212 of electrodialysis device 202);
- protonating, using a volume of a protonating species, the volume of the organic anion to generate the volume of the organic acid (para [0043], "protons are generated in the anode compartment 208 ... protons pass through the cation exchange membrane 214a into the central ion exchange compartment 212 ... protons displace the alkali metal ions (e.g., potassium ions) in the product stream 154 to acidify the stream and produce a product stream 260 including an organic acid product");
- migrating, across a cation exchange membrane, the volume of cations into a base chamber of the electrodialysis electrolyzer (para [0043], "The displaced alkali metal ions may pass through the cation exchange membrane 214b to the cathode compartment 210");
- generating a volume of hydroxide anions in a cathode area of the electrodialysis electrolyzer, whereby the volume of hydroxide anions and the volume of cations combine in the base chamber of the electrodialysis electrolyzer to generate at least a part of the second volume of the base in the cathode area of the electrodialysis electrolyzer (para [0043], "The displaced alkali metal ions ... combine with hydroxide ions (OH−) formed from water reduction at the cathode 218 to form an alkali metal hydroxide, preferably potassium hydroxide");
- obtaining at least a part of the first stream from the base chamber of the electrodialysis electrolyzer (figure 2, first stream 246 emerges from base compartment 210 of the electrodialyzer 202); and
- obtaining the second stream from the electrodialysis electrolyzer (para [0043] and figure 2, the second stream ("product stream", referred to as #260 in the text but #230 in the figure) is obtained from the electrodialysis device 202).
Regarding claim 13, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Overa further teaches:
the organic anion is one of acetate and propionate (pg 738 abstract, the organic anion is acetate; pg 739 figure 1c, a minor side product of propionate is also formed);
the base is potassium hydroxide (pg 740 left column para 2); and
the reduction substrate is carbon monoxide (pg 739 figure 1a and caption, “reduction of CO on the Cu catalyst surface (cathode)”.
Oveda does not explicitly teach that the acid is acetic or propionic acid, and the cation is sodium or potassium. However, when Oveda is modified to incorporate the separation process of Kaczur 2013, it flows naturally from the teachings of the combination that the organic acid produced by the separation will the conjugate acid of Oveda’s organic anion (i.e. acetic acid, from Oveda’s acetate), and the cation will be the cation that is present in Oveda’s base (i.e. potassium, from Oveda’s potassium hydroxide). The claimed features, wherein the acid is acetic or propionic acid and the cation is sodium or potassium, therefore cannot form a basis for patentability because they are features that would arise naturally from following the suggestion of the prior art (MPEP 2145(II); Ex parte Obiaya, 227 USPQ 58, 60 (Bd. Pat. App. & Inter. 1985)).
Regarding claim 14, Overa in view of Kaczur 2013 renders the method of claim 1 obvious. Overa further teaches the liquid stream is obtained from the anode area of the carbon monoxide electrolyzer (pg 739 right column para 1, “electrolyser is designed to produce a concentrated liquid product stream in the anode chamber”) via a first gas-liquid separator coupled to the anode area of the electrolyzer to separate oxygen gas from the liquid organic ion solution product (pg 744 right column para 2); a second liquid-gas separator is coupled to the cathode area of the electrolyzer (pg 739 figure 1a and text, the cathode is a gas diffusion electrode to which carbon monoxide is fed in gas phase, and a gas stream exiting the cathode contains CO and some reduction products; pg 740 left column para 2 and pg 744 left column para 5, the cathode output stream is passed through a cold trap to condense reduction products and thereby separate them from CO). Overa also teaches that the method further comprising recirculating the base stream to the carbon monoxide electrolyte to maintain a pH of an electrolyte of the carbon monoxide electrolyzer (pg 740 left column para 2, a 3 M KOH solution was continually circulated through the anode area to maintain a strongly alkaline anolyte in the anode area; pg 739 figure 1d and pg 740 right column para 2, Overa varied the KOH concentration of anolyte and observed that product concentration and purity improved with increasing alkalinity up to a KOH concentration of 7 M).
Kaczur 2013 further teaches the liquid stream comprising organic anion is obtained by gas-liquid separation of the catholyte stream of the oxocarbon electrolyzer (figure 1, catholyte 146 is sent to gas liquid separator 150 to obtain potassium formate liquid stream 154), and the anolyte stream of the oxocarbon electrolyzer is subjected to gas-liquid separation as well (figure 1, anolyte stream 124 is sent to gas liquid separator 128); the liquid stream is obtained from an anode area of the oxocarbon electrolyzer and the cathode area of the oxocarbon electrolyzer (figure 1 and para [0035]-[0041], liquid stream 154 is obtained by electrochemical reduction of CO2 162 at cathode area 120, coupled to electrochemical water oxidation reaction at anode area 116); the separation process is conducted by a single separator (components that carry out the separation process (shown at figure 2 #200 and figure 6) collectively constitute a single separation system); and the method further comprises recirculating the first stream to the oxocarbon electrolyzer to maintain a pH of an electrolyte of the oxocarbon electrolyzer (figure 3 and para [0047], the base stream (i.e. first stream) from separation system 200 is recycled via recycle loop 302 to provide bicarbonate (base) to the electrolyzer 100; para [0039]-[0041], bicarbonate is metered into the catholyte of electrolyzer 100 for the purpose of maintaining pH).
Regarding claim 15, Overa in view of Kaczur 2013 renders the method of claim 14 obvious. Overa further teaches the cathode is a gas phase area (pg 739 figure 1a, pg 744 left column para 5, the cathode is a Cu-catalyzed gas diffusion cathode) and the liquid stream is obtained from the anode using a gas-liquid separator (pg 744 right column para 2, “a gas-liquid separator was placed in the anode outlet”). Kaczur 2013 teaches that the anolyte stream of their oxocarbon electrolyzer is subjected to gas-liquid separation as well (figure 1, anolyte stream 124 is sent to gas liquid separator 128).
Regarding claim 16, Overa in view of Kaczur 2013 renders obvious the method of claim 1. Overa teaches generating a useful species using the carbon monoxide electrolyzer wherein the useful species is the organic acid (pg 743 left column para 1, Overa teaches electrochemical production of acetic acid).
Kaczur 2013 similarly teaches generating a useful species using their oxocarbon electrolyzer wherein (i) the useful species is the organic acid (para [0035]-[0041] the oxocarbon electrolyzer generates potassium formate; para [0038], acidic protons generated at the anode are able to cross over and interact with the catholyte, therefore at least some amount of formic acid exists in equilibrium with formate in the electrolyzer-produced liquid stream); and (ii) the second stream is a purified stream of the organic acid (para [0043] and [0078], product stream 260 is a stream of the organic acid and is purified relative to the liquid stream).
Regarding claim 17, Kaczur 2013 teaches the method of claim 1, further comprising: supplying the liquid stream to an electrodialysis electrolyzer (figure 2, liquid stream 154 is supplied to area 212 of electrodialysis device 202); and obtaining the first stream and the second stream from the electrodialysis electrolyzer (para [0043] and figure 2, the first stream 246 emerges from base compartment 210 of the electrodialyzer 202, and the second stream ("product stream", referred to as #260 in the text but #230 in the figure) is obtained from a central compartment 212); wherein a reduction substrate of the electrodialysis electrolyzer is water (para [0043], "cathode compartment 210 includes a cathode 218 suitable to reduce water and to generate an alkali metal hydroxide").
Regarding claim 19, Kaczur 2013 teaches the method of claim 1, further comprising: recirculating the first stream to the oxocarbon electrolyzer to maintain a pH of an electrolyte of the oxocarbon electrolyzer (figure 3 and para [0047], the base stream (first stream) from separation system 200 is recycled via recycle loop 302 to provide bicarbonate (base) to the electrolyzer 100; para [0039]-[0041], bicarbonate is metered into the catholyte of electrolyzer 100 for the purpose of maintaining desired pH); and recirculating, while generating the first stream and the second stream, a third stream to the oxocarbon electrolyzer to maintain at least one of a pH and a conductivity of the electrolyte, wherein the third stream was generated in a prior iteration of the separation process (figure 3, a third stream comprising CO2 gas generated by separator 200, said CO2 gas stream is recirculated to "CO2 collection and distribution", then metered into base recycle loop to react with KOH yielding KHCO3 (potassium bicarbonate); para [0039]-[0041], bicarbonate is metered into the catholyte of electrolyzer 100 for the purpose of maintaining desired pH).
Regarding claim 25, Overa teaches a method comprising:
supplying a volume of carbon monoxide to a cathode area of a carbon monoxide electrolyzer to be used as a reduction substrate (pg 738, “Here, we report a CO electrolyser”; pg 739 figure 1a and caption, “reduction of CO on the Cu catalyst surface (cathode)”; pg 744 left column para 5, “Carbon monoxide gas was fed to the cathode end plate using a mass flow controller”);
generating a volume of an organic anion, in an anode area of the carbon monoxide electrolyzer, using the reduction substrate (per pg 739 figure 1a, and pg 739 left column para 1 – pg 740 left column para 2, carbon monoxide is reduced at the cathode to a mix of intermediate products including ethanol, the intermediates are transferred to the anode compartment, and the intermediates are then oxidized at the anode to form acetate and propionate ions; thus, the reduction substrate that was supplied to the cathode (carbon monoxide) is used to generate a volume of organic anion (acetate) in the anode area of the electrolyzer);
obtaining a liquid stream from the anode area of the carbon monoxide electrolyzer, wherein the liquid stream includes the volume of the organic anion and a volume of a base (pg 739 right column para 1, “electrolyser is designed to produce a concentrated liquid product stream in the anode chamber”; pg 739 figure 1d, anolyte concentration is maintained at a KOH concentration of from 1M to 9 M, i.e. the liquid stream obtained from the anode area includes a volume of base); and
recycling a volume of the base to the anode area of the carbon monoxide electrolyzer to maintain a strongly alkaline anolyte in the anode area (pg 740 left column para 2, a three molar KOH solution was continually circulated through the anode area to maintain a strongly alkaline anolyte in the anode area; pg 739 figure 1d and pg 740 right column para 2, Overa varied the KOH concentration of anolyte and observed that product concentration and purity improved with increasing alkalinity up to a KOH concentration of 7 M).
Overa also contemplates combining their carbon monoxide electrolysis process with a separation and solvent/base recycle process, to produce a first stream comprising the organic anion product and a second stream comprising the potassium hydroxide recycle (discussed at pg 743 left column para 1, and illustrated in Supplementary information, pg 22, Supplementary figure 25).
However, Overa does not disclose a separation process characterized in that (i) the separation process uses a bipolar membrane electrodialysis process; (ii) the separation process separates a volume of a cation from the liquid stream; (iii) the first stream includes a second volume of the base; (iv) the second stream includes a volume of an organic acid; (v) the volume of the organic acid includes the volume of the organic anion; and (vi) the second volume of the base includes the volume of the cation.
Kaczur 2013 is directed to a method of electrolytically reducing CO2 to formate (an organic anion), comprising:
- supplying a volume of CO2 to a cathode area of an oxocarbon electrolyzer to be used as a reduction substrate (figure 1 and para [0039], CO2 is supplied to the cathode area 110 of electrolyzer 102, where the CO2 is used a reduction substrate);
- generating a volume of an organic anion using the reduction substrate (figure 1 and para [0039], CO2 is reduced at the cathode to generate the organic anion formate);
- obtaining a liquid stream from the oxocarbon electrolyzer, wherein the liquid stream includes the volume of the organic anion and a volume of a base (figure 1 and para [0039]-[0040], cathode output 146 is sent to gas-liquid separator 150 which outputs a liquid product stream 154 which includes the organic anion (formate) and may also contain hydroxide (a base); para [0040]-[0041] pH of the product stream is monitored by pH sensor 148b, and additional base can be metered in to maintain desired pH level); and
- generating, using a separation process and from the liquid stream, a first stream and a second stream, whereby the first stream and the second stream are separate (figure 2 and para [0042]-[0046], "electrochemical acidification system 200" separates the cathode product stream into a first stream 246 comprising base, and a second stream (referred to as #260 in the text but #230 in the figure) comprising formic acid; figure 3 shows how electrolyzer unit 100 is connected to separation system 200),
wherein:
- (i) the separation process uses a bipolar membrane electrodialysis process (figure 4, para [0075]);
- (ii) the separation process separates a volume of a cation from the liquid stream (see figures 2 and 4, and para [0043]: the alkali cation from the alkali formate liquid stream is separated by drawing the cation across cation exchange membrane 214b into stream 246);
- (iii) the first stream includes a second volume of the base (para [0046], "cathode exit stream 246 ... includes an alkali metal hydroxide (such as potassium hydroxide where the product steam 154 includes potassium formate)");
- (iv) the second stream includes a volume of an organic acid (para [0043], "product stream 260 including an organic acid product, preferably formic acid");
- (v) the volume of the organic acid includes the volume of the organic anion (para [0042] and figures 2 and 4, the organic acid product stream is the conjugate acid formed by protonating the organic anion); and
- (vi) the second volume of the base includes the volume of the cation (para [0042]-[0046], alkali cations drawn from the liquid stream 154, across membrane 214b, into the first stream 246, combine with hydroxide ions in cathode chamber 210 to form the alkali hydroxide base in the first stream 246); and
recycling a volume of base from the separation process to the electrolyzer (para [0046]-[0048], figure 3, showing the KOH / KHCO3 base stream from separation stage 200 is recycled to electrolysis stage 100).
It would have been obvious to a person having ordinary skill in the art before the effective filing date of the claimed invention to incorporate, into Oveda’s method, the nanofiltration / electrodialysis separation process of Kaczur 2013, because Oveda is directed to an electrolysis process forming a product stream comprising an organic anion (acetate) in aqueous base, and is motivated to combine it with a separation process for separating the anion from the base (pg 743 left column para 1, and illustrated in Supplementary information, pg 22, Supplementary figure 25); and Kaczur 2013, who is similarly directed to an electrolysis process that yields a liquid product stream, separates it into an organic anion product and an aqueous base, and recycles the base to the electrolyzer, teaches a nanofiltration and electrodialysis process which is effective to this end. The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 26, Overa and Kaczur 2013 render the method of claim 25 obvious, and Kaczur 2013 further teaches:
the separation process includes a membrane separation process and an acid-base separation process (separation process includes nanofiltration process as described in figure 6 and para [0078], and acid-base separation process described in figure 2 and para [0042]-[0046]);
the membrane separation process generates a concentrated salt solution (para [0078] and figure 6, nanofiltration process generates a permeate solution of organic anion salt (formate salt) and a reject stream concentrated in potassium carbonate salt; para [0158]-[0160], the nanofiltration gives a negative rejection percentage for formate, meaning the permeate has a higher formate concentration than the feed);
the acid-base separation process generates the volume of the organic acid (para [0042]-[0046]); and
the membrane separation process and the acid-base separation process each generate the second volume of the base (para [0078], reject stream from the membrane separation process is sent to block 302 where it is merged into the first stream comprising second volume of base; figure 3, the catholyte stream of the acid-base separation process is split, with a portion being recirculated into the acid-base separation process (shown in more detail in figure 2) and a portion being diverted to block 302 where it forms a portion of the second base in the first stream; therefore the nanofiltration process and the acid-base separation process each generate a stream comprising a portion of the second volume of base).
Regarding claim 27, Overa and Kaczur 2013 render the method of claim 25 obvious, and Kaczur 2013 further teaches the separation process comprises:
applying the liquid stream to a membrane separator to produce a concentrated organic salt solution (para [0078] and figure 6, liquid stream is applied to a nanofiltration membrane to produce potassium formate permeate stream; para [0158]-[0160], the nanofiltration gives a negative rejection percentage for formate, meaning the permeate has a higher formate concentration than the feed);
acidifying the concentrated organic salt solution with a volume of generated acid to produce a volume of an organic acid and alkali metal salt solution (para [0078], potassium formate permeate stream is sent to "electrochemical acidification system 200"; figure 2, figure 4, and para [0042]-[0046], "electrochemical acidification system 200" generates hydrogen ions, which displace potassium ions in the potassium formate solution to produce formic acid (organic acid) while the displaced alkali metal ion combines with a hydroxide ion to form potassium hydroxide);
removing the volume of the organic acid from the volume of organic acid and metal salt solution to produce a volume of a metal salt solution and the second stream (figure 2, para [0042]-[0046], the organic acid and the metal hydroxide salt solution are separated into first stream 246 comprising metal hydroxide, and a second stream (referred to as #260 in the text but #230 in the figure) comprising the organic acid); and
applying the volume of the metal salt solution to an acid-base generator (figure 2, metal salt stream 246 is recirculated back to the acid base generator 202); wherein the acid-base generator generates the volume of generated acid prior to the acidifying step (figure 2 and para [0043], acid-based generator 202 first generates acid in anode compartment 208, and then migrates that acid across CEM 214a to central compartment 212 where the acidifying step takes place) and uses the volume of the metal salt solution to generate more of the generated acid (figure 2 and para [0046], the metal salt solution is recirculated back into electrochemical acid base generator 202 system for further acid generation).
Regarding claim 28, Overa and Kaczur 2013 render the method of claim 25 obvious. Overa teaches recycling a volume of the base to the anode area of the carbon monoxide electrolyzer to maintain a strongly alkaline anolyte in the anode area (pg 740 left column para 2, a three molar KOH solution was continually circulated through the anode area to maintain a strongly alkaline anolyte in the anode area; pg 739 figure 1d and pg 740 right column para 2, Overa varied the KOH concentration of anolyte and observed that product concentration and purity improved with increasing alkalinity up to a KOH concentration of 7 M). Overa also contemplates combining their carbon monoxide electrolysis process with a separation and solvent/base recycle process, to produce a first stream comprising the organic anion product and a second stream comprising the potassium hydroxide recycle (discussed at pg 743 left column para 1, and illustrated in Supplementary information, pg 22, Supplementary figure 25).
Kaczur 2013 teaches their first stream is the separation process output stream that comprises the base, and further teaches recirculating the first stream to their oxocarbon electrolyzer to maintain at least one of a pH and a conductivity of an electrolyte of the oxocarbon electrolyzer (figure 3 and para [0047], the base stream (first stream) from separation system 200 is recycled via recycle loop 302 to provide bicarbonate (base) to the electrolyzer 100; para [0039]-[0041], bicarbonate is metered into the catholyte of electrolyzer 100 for the purpose of maintaining desired pH).
Regarding claim 29, Overa and Kaczur 2013 render the method of claim 25 obvious, and Kaczur 2013 further teaches the separation process further comprises:
supplying the liquid stream to a separating area of an electrodialysis electrolyzer (figure 2, liquid stream 154 is supplied to area 212 of electrodialysis device 202);
protonating, using a volume of a protonating species, the volume of the organic anion to generate the volume of the organic acid (para [0043], "protons are generated in the anode compartment 208 ... protons pass through the cation exchange membrane 214a into the central ion exchange compartment 212 ... protons displace the alkali metal ions (e.g., potassium ions) in the product stream 154 to acidify the stream and produce a product stream 260 including an organic acid product");
migrating, across a cation exchange membrane, the volume of cations into a base chamber of the electrodialysis electrolyzer (para [0043], "The displaced alkali metal ions may pass through the cation exchange membrane 214b to the cathode compartment 210");
generating a volume of hydroxide anions in a cathode area of the electrodialysis electrolyzer, whereby the volume of hydroxide anions and the volume of cations combine in the base chamber of the electrodialysis electrolyzer to generate at least a part of the second volume of the base in the cathode area of the electrodialysis electrolyzer (para [0043], "The displaced alkali metal ions ... combine with hydroxide ions (OH−) formed from water reduction at the cathode 218 to form an alkali metal hydroxide, preferably potassium hydroxide");
obtaining at least a part of the first stream from the base chamber of the electrodialysis electrolyzer (figure 2, first stream 246 emerges from base compartment 210 of the electrodialyzer 202); and
obtaining the second stream from the acid chamber of the electrodialysis electrolyzer (para [0043] and figure 2, the second stream ("product stream", referred to as #260 in the text but #230 in the figure) is obtained from the electrodialysis device 202; as shown in figure 4, the product stream is obtained from the acid chamber of a two-compartment (acid/base) bipolar electrodialysis stack).
Regarding claim 33, Overa and Kaczur 2013 render the method of claim 1 obvious. Kaczur 2013 further teaches the membrane separation process at least partially separates the volume of organic anion and the volume of the base (para [0078], “The nano-filtration system is preferably utilized to separate alkali metal formate (e.g., potassium formate) from bicarbonate leaving the electrolyzer system 100 (e.g., stream 154)”).
Regarding claim 34, Overa and Kaczur 2013 render the method of claim 1 obvious. Kaczur 2013 further teaches the membrane separation process comprises nanofiltration (para [0078]).
Regarding claim 35, Overa and Kaczur 2013 render the method of claim 1 obvious. Kaczur 2013 further teaches the membrane separation process generates a concentrated salt solution (para [0078] and figure 6, the nanofiltration process generates a permeate solution of organic anion salt (formate salt) and a reject stream concentrated in potassium carbonate salt (a first portion of base); para [0158]-[0160], the nanofiltration gives a negative rejection percentage for formate, meaning the permeate solution has a higher concentration of formate salt than the feed solution, and therefore reads on a concentrated salt solution).
Regarding claim 36, Overa and Kaczur 2013 render the method of claim 26 obvious. Kaczur 2013 further teaches the membrane separation process comprises nanofiltration (para [0078]).
Claims 11, 12, and 30 are rejected under 35 U.S.C. 103 as being unpatentable over Overa and Kaczur 2013 as applied to claims 10 and 29 above, in further view of Oda et al (US 2,829,095 A).
Regarding claim 11, Overa and Kaczur 2013 render obvious the method of claim 10. Kaczur 2013, in teaching the separation device, discloses a two-compartment electrodialysis electrolyzer comprising acid chamber(s) and base chamber(s) (figure 4), wherein an anode area is isolated from an acid chamber by a bipolar membrane (figure 4, the anode area (leftmost chamber) is separated from the central acid compartment (compartment that receives potassium formate and outputs formic acid) by a bipolar membrane) and a cathode area is isolated from a base chamber by another bipolar membrane (figure 4, the cathode area (rightmost chamber) is separated from the more central base compartment (compartment that receives DI water or KOH, and outputs KOH solution) by a second bipolar membrane). Kaczur 2013 does not teach their electrodialysis electrolyzer is arranged as a three compartment electrodialysis device having acid chamber(s), base chamber(s), separating chamber(s) positioned between the acid and base chamber(s).
Oda teaches an electrodialysis electrolyzer which is useful for converting an anion to its conjugate acid (col 1 ln 15-42). Oda's device is a three-chamber electrodialyzer comprising a separating chamber, an acid chamber, and a base chamber (figure 1, separating chambers 4, acid chambers 5, and base chambers 6; col 1 ln 50 - col 2 ln 2), wherein an anode area of the electrodialysis electrolyzer is isolated from the acid chamber of the electrodialysis electrolyzer by a first bipolar membrane (figure 1, the rightmost of the bipolar membranes 2 separates anode chamber 8 from each of the acid chambers 5); the separating area of the electrodialysis electrolyzer is located between the acid chamber of the electrodialysis electrolyzer and the base chamber of the electrodialysis electrolyzer (figure 1, each separating area 4 is between a corresponding acid chamber 5 and base chamber 6); and the cathode area of the electrodialysis electrolyzer is isolated from the base chamber of the electrodialysis electrolyzer by a second bipolar exchange membrane (figure 1, the leftmost of the bipolar membranes 2 separates cathode chamber 7 from each of the base chambers 6). Oda teaches that their electrodialysis electrolyzer is effective to convert an organic anion to its conjugate acid (col 4 ln 53-75, in Example 2 Oda converts sodium acetate to acetic acid).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify Overa and Kaczur 2013 by using, as the electrodialysis electrolyzer in the separation system, a three-compartment bipolar electrodialyzer as disclosed in Oda, because Overa is directed to forming and purifying acetate; Kaczur 2013 teaches the use of electrodialysis to isolate an organic acid from a stream comprising its alkali conjugate base (in Kaczur 2013’s case, it is formic acid potassium formate), and Oda teaches that their electrodialyzer arrangement is effective for isolating an organic acid from the corresponding alkali salt (col 4 ln 53-75, Oda demonstrates effective separation of acetic acid from a solution of sodium acetate). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 12, Overa and Kaczur 2013 render the method of claim 10 obvious. Kaczur 2013, in teaching the separation process, discloses a two-compartment electrodialysis electrolyzer comprising acid chamber(s) and base chamber(s) (figure 4; para [0075]), wherein the protonating step occurs in an acid chamber (figure 4, protonating of formate to formic takes place in the acid compartment of a two-compartment bipolar electrodialyzer) and the second stream is obtained from the acid chamber of the electrodialysis electrolyzer (figure 4, formic acid stream is obtained from the same chamber that the protonating took place in). Kaczur 2013 does not teach their electrodialysis electroyzer has a separating chamber that is separated from the acid chamber by an anion exchange membrane, or that the supplying step involves supplying the liquid stream to the separating chamber; Kaczur 2013 supplies their liquid stream directly to the acid chamber (figure 4).
Oda teaches an electrodialysis electrolyzer which is useful for converting an organic anion to its conjugate acid (col 1 ln 15-42; col 4 ln 54-75). Oda's device is a three-chamber electrodialyzer comprising a separating chamber, an acid chamber, and a base chamber (figure 1, separating chambers 4, acid chambers 5, and base chambers 6; col 1 ln 50 - col 2 ln 2), wherein a step of protonating of the anion step occurs in an acid chamber of the electrodialysis electrolyzer (col 2 ln 3-49); the acid chamber is separated from a separating chamber of the electrodialysis electrolyzer by an anion exchange membrane (figure 1, acid chambers 5 are separated from neighboring separating chambers 4 by anion excahgne membranes 1; col 1 ln 50-72); a step of supplying the anion involves supplying a liquid stream containing the anion to the separating chamber (col 1 ln 56-60; col 4 ln 55-65, sodium acetate solution is supplied to the separating chamber); and a stream comprising the organic acid is obtained from the acid chamber of the electrodialysis electrolyzer (col 4 ln 65-75, acetic acid is obtained from the acid chamber). Oda teaches that their electrodialysis electrolyzer is effective to convert an organic anion to its conjugate acid (col 4 ln 53-75, Oda converts sodium acetate to acetic acid).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify Overa and Kaczur 2013 by using by using, as the electrodialysis electrolyzer in the separation system, a three-compartment bipolar electrodialyzer as disclosed in Oda, because Overa is directed to forming and purifying acetate; Kaczur 2013 teaches the use of electrodialysis to isolate an organic acid from a stream comprising its alkali conjugate base (in Kaczur 2013’s case, it is formic acid potassium formate); and Oda teaches that their electrodialyzer arrangement is effective for isolating an organic acid from the corresponding alkali salt (col 4 ln 53-75, Oda demonstrates effective separation of acetic acid from a solution of sodium acetate). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Regarding claim 30, Overa and Kaczur 2013 render obvious the method of claim 29, with Kaczur 2013 further teaching protonating of the volume of the organic anion occurs in an acid chamber of the electrodialysis device, and obtaining the second stream from the acid chamber (as shown in figure 4, the liquid stream comprising the organic anion is fed right into the acid chamber of a two-compartment (acid/base) bipolar electrodialysis stack, and the product stream is obtained from the same chamber). Kaczur 2013 does not teach migrating the volume of the organic anion across an anion exchange membrane, into an acid chamber of the electrodialysis electrolyzer.
Oda teaches an electrodialysis electrolyzer which is useful for converting an organic anion to its conjugate acid (col 1 ln 15-42; col 4 ln 54-75). Oda's device is a three-chamber electrodialyzer comprising a separating chamber, an acid chamber, and a base chamber (figure 1, separating chambers 4, acid chambers 5, and base chambers 6; col 1 ln 50 - col 2 ln 2), wherein a step of protonating of the anion step occurs in an acid chamber of the electrodialysis electrolyzer (col 2 ln 3-49); the acid chamber is separated from a separating chamber of the electrodialysis electrolyzer by an anion exchange membrane (figure 1, acid chambers 5 are separated from neighboring separating chambers 4 by anion exchange membranes 1; col 1 ln 50-72); a step of supplying the anion involves supplying a liquid stream containing the anion to the separating chamber and migrating the anion across an anion exchange membrane to the acid chamber (col 1 ln 56-60; col 4 ln 55-65, sodium acetate solution is supplied to the separating chamber, and the acetate migrates into the acid chamber which is separated from the separating chamber by an anion exchange membrane); and a stream comprising the organic acid is obtained from the acid chamber of the electrodialysis electrolyzer (col 4 ln 65-75, acetic acid is obtained from the acid chamber). Oda teaches that their electrodialysis electrolyzer is effective to convert an organic anion to its conjugate acid (col 4 ln 53-75, in Example 2 Oda converts sodium acetate to acetic acid).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify Overa and Kaczur 2013 by using, as the electrodialysis electrolyzer in the separation system of Kaczur 2013, a three-compartment bipolar electrodialyzer as disclosed in Oda, because Overa is directed to forming and purifying acetate; Kaczur 2013 teaches the use of electrodialysis to isolate an organic acid from a stream comprising its alkali conjugate base (in Kaczur 2013’s case, it is formic acid potassium formate); and Oda teaches that their electrodialyzer arrangement is effective for isolating an organic acid from the corresponding alkali salt (col 4 ln 53-75, Oda demonstrates effective separation of acetic acid from a solution of sodium acetate). The claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Claim 18 is rejected under 35 U.S.C. 103 as being unpatentable over Oveda and Kaczur 2013 as applied to claim 17 above, and further in view of Mani et al (US 6,221,225 B1).
Regarding claim 18, Oveda and Kaczur 2013 redner obvious the method of claim 17. Oveda teaches that a volume of dihydrogen is generated in a cathode area of the electrolyzer (pg 739 figure 1b); Kaczur 2013, too, teaches that a volume of dihydrogen is generated in a cathode area of their oxocarbon electrolyzer (para [0039]). However, Oveda and Kaczur 2013 do not teach supplying the volume of dihydrogen to an anode area of the electrodialysis electrolyzer, whereby the first stream and the second stream are generated by the electrodialysis electrolyzer using the volume of dihydrogen as an oxidation substrate.
Mani is directed to a process for separating organic acids by way of an electrodialysis electrolyzer (col 1 ln 8-16, 41-50). Mani's process is similar to Kaczur 2013's separation sub-process, in that base is generated at a cathode chamber of the electrodialyzer, acid is generated at an anode chamber, the conjugate base salt of the organic acid is fed into the electrodialyzer, and protons displace the counterion of the organic anion to yield the organic acid (see Mani at col 4 ln 39-61; figure 3, H+ is generated at chamber A', OH− is generated at chamber B, salt MX is fed into salt chamber S/A, protons disclose the metal ion M, producing first stream from chamber B comprising base (MOH), and second stream from chamber S/A comprising the acid HX). Furthermore, Mani teaches that dihydrogen gas generated at the cathode is collected and supplied to the anode area of the electrodialyzer, whereby the electrodialysis electrolyzer uses the volume of dihydrogen as an oxidation substrate (figure 3; col 6 ln 59 - col 7 ln 22). Mani teaches that capturing the generated hydrogen from a cathode and feeding it to the anode can improve efficiency and reduce the amount of electrical power required for electrodialytic water splitting (col 6 ln 59-65).
It would have been obvious to a person having ordinary skill in the art at the time of the invention to modify Oveda and Kaczur 2013 by capturing the hydrogen gas stream, which Oveda and Kaczur 2013 are generating at the electrolysis cathode, and directing the hydrogen gas to the anode chamber of the electrodialysis electrolyzer as taught in Mani, in order to make efficient use of side products and reduce the power consumption of the electrochemical system (Mani at col 6 ln 59-65). Furthermore, the claimed limitations are obvious because all the claimed elements were known in the prior art and one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Claims 31 and 32 are rejected under 35 U.S.C. 103 as being unpatentable over Oveda and Kaczur 2013 as applied to claims 6 and 27, in further view of "Kaczur 2017" (US 2017/0121831 A1 to Kaczur et al).
Regarding claims 31 and 32, Oveda and Kaczur 2013 render obvious the methods of claims 6 and 27 respectively, but, the acid-base generator in Kaczur 2013's separation process is a water splitting electrolyzer (para [0042]-[0046]). Kaczur 2013 does not disclose the acid-base generator includes a chlor-alkali reactor.
Kaczur 2017 is similarly directed to a method of electrochemically converting carbon dioxide to an organic acid, the method comprising:
supplying a volume of oxocarbon to a cathode area of an oxocarbon electrolyzer, and reducing the oxocarbon to generate a volume of an organic anion (figure 6, CO2 source 680 (an oxocarbon) is fed into the reduction half (i.e. the cathode area) of electrolyzer 610, where the CO2 is reduced to formate (an organic anion), which is further converted to oxalate (another organic anion) at reactor 620);
obtaining a basic liquid stream including the volume of the organic anion and a volume of a base (figure 6, at 620, NaOH is added to the stream and formate condenses to oxalate, yielding a basic stream comprising sodium oxalate; para [0070]-[0073]); and
generating, using a separation process and from the liquid stream, a first stream comprising the conjugate acid of the organic anion, and a second stream comprising the base (figure 6, the sodium oxalate is directed into electrochemical acidification unit 630 where it is separated into oxalic acid and sodium hydroxide; para [0071]; alternatively, the anion can be formate and the acid can be formic acid, per para [0076]);
wherein the separation process includes acidifying the organic salt solution with a volume of generated acid to produce a volume of an organic acid and alkali metal salt solution (para [0018]-[0020], separation process can comprise reacting sodium oxalate with hydrochloric acid to produce oxalic acid and sodium chloride; para [0071]);
separating the organic acid from the metal salt (para [0019]), and recycling the metal salt to the acid base generator to generate more acid (para [0020]), wherein in one embodiment the acid-base generator comprises a water electrolyzer (embodiment of figures 1A and 2A, acid-base generator 140 electrolyzes water to H2 and O2), and in an alternative embodiment the acid-base generator comprises a chlor-alkali generator (para [0020], the sodium chloride is electrolyzed to chlorine in a chlor-alkali cell, then the chlorine is reacted with hydrogen gas to regenerate hydrochloric acid; figure 6, electrochemical acidification unit 630 separates oxalic acid from NaOH while also performing chlor-alkali electrolysis).
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 separation process of Kaczur's 2013 disclosure by incorporating, from Kaczur's 2017 disclosure, the feature of wherein the acid-base generator is a chlor-alkali generator, because Kaczur 2013’s separation process differs only in that they use a water splitting electrolyzer as the acid-base generator, and Kaczur 2017, which is similarly directed to electrolytically generating an organic anion and then converting the organic anion to its conjugate acid by way of an electrochemical acid-base generator, teaches that either a water-splitting electrolyzer or a chlor-alkali generator is appropriate to use as the acid-base generator. The claimed limitations are obvious because all the claimed elements were known in the prior art, one skilled in the art could have combined the elements as claimed by known methods with no change in their respective functions, one would reasonably anticipate the method of modified Kaczur 2013 to be operable based on Kaczur 2017's disclosure, and the combination yielded nothing more than predictable results [MPEP 2143(A)].
Response to Arguments
Applicant's arguments (see Remarks pg 12-24 filed 22 December 2025), with respect to the §103 rejection based on Overa and Kaczur 2013, have been fully considered but they are not persuasive.
Applicant argues (Remarks pg 14-15) that Overa does not disclose the claimed feature of obtaining, from the anode area of the CO electrolyzer, a liquid stream comprising a volume of base, subjecting the liquid stream to a separation process that yields a second volume of base, and recycling the second volume of base to the anode area of the CO electrolyzer. Applicant points out that the second volume of base which Overa feeds into their CO electrolyzer is not base that was separated from the first volume. Applicant notes that, in the disclosure of Kaczur 2013, the first volume of base (which is subjected to separation to yield a second volume of base) is obtained from the cathode side of Kaczur 2013’s electrolysis cell, rather than the anode side as claimed. Applicant thereby argues that the applied references do not teach the claimed subject matter.
Applicant’s argument is unpersuasive because one cannot show nonobviousness by attacking references individually where the rejections are based on combinations of references. The test for obviousness is not whether the features of a secondary reference may be bodily incorporated into the structure of the primary reference; nor is it that the claimed invention must be expressly suggested in any one or all of the references. Rather, the test is what the combined teachings of the references would have suggested to those of ordinary skill in the art. See In re Keller, 642 F.2d 413, 208 USPQ 871 (CCPA 1981).
Overa obtains, from the anode side of their cell, a product stream comprising the organic anion product and a first volume of base, and suggests it would be desirable to separate the two to isolate the desired organic product. Kaczur 2013 discloses the recited separation process for taking, from an electrolysis device, a liquid stream comprising an organic anion and a first volume of base; separating them; and recycling a second volume of base from the separation process back to the electrolysis cell. Each feature of the claim is taught by one reference or the other, and the combined teachings of the references suggest the combination that would result in the claimed subject matter. Therefore rejection under §103 is warranted.
Applicant furthermore argues (Remarks pg 15) that it would not be obvious to incorporate Kaczur 2013’s separation process into the method of Overa because Overa teaches a different separation scheme. Applicant argues that Overa’s disclosure of one separation process constitutes a teaching away from different separation processes.
This argument is unpersuasive because a reference does not teach away when it
merely expresses a general preference for an alternative invention but does not criticize, discredit or otherwise discourage investigation into the invention claimed (MPEP 2145(X)(D)(1)).
Applicant furthermore argues (Remarks pg 16) that, if the second volume of base were recycled as suggested in Kaczur 2013, but delivered to the anode compartment of Overa’s cell, then the performance of Overa’s method would be impaired, because Overa’s synthesis of acetate requires the base concentration of the electrolysis cell anolyte to be precisely controlled, and the recycled base stream would have a poorly controlled base concentration.
This argument is unpersuasive because Overa shows that the base concentration of the anolyte does not need to be precisely controlled (Supplementary pg 10 figure S9, showing the electrolysis is operable for anolyte base concentrations ranging from 1 M to 9 M). The argument is also unpersuasive because Kaczur 2013 discloses a way the base concentration of the base entering the electrolyzer could be controlled (para [0039]-[0041]).
Applicant furthermore argues (Remarks pg 16-17) that the technical problem faced by the inventor is a different one than that faced by Overa, and therefore Applicant’s reasons for combining electrolysis with membrane separation are not relevant to Overa.
In response, note that the reasons why we find it obvious to modify Overa in view of Kaczur 2013 were drawn from the content of the references themselves, not from the content of Applicant’s disclosure. The reason or motivation to modify the reference may often suggest what the inventor has done, but for a different purpose or to solve a different problem. It is not necessary that the prior art suggest the combination to achieve the same advantage or result discovered by applicant. See, e.g., In re Kahn, 441 F.3d 977, 987, 78 USPQ2d 1329, 1336 (Fed. Cir. 2006).
Applicant argues (Remarks pg 17-19) that claim 2 is distinguished from the applied references by the recitation that the membrane separation process separates a first portion of the base, the acid-base separation separates a second portion of the base, and the first and second portions comprise the same base. Applicant argues that this feature is not met because Kaczur 2013’s membrane separation process produces potassium carbonate base, and their acid-base separation produces potassium hydroxide.
In response note that the base stream obtained at Kaczur’s membrane nanofiltration step is an aqueous potassium carbonate stream, to which potassium hydroxide was added both upstream and downstream of the filter (para [0078]). It should also be recognized that, Kaczur’s nanofiltration is being performed at pH ~11 (para [0158]-[0162]), a pH where it is well known that aqueous potassium carbonate is a buffer which exists in dynamic equilibrium with KOH and KHCO3
K
2
C
O
3
+
H
2
O
↔
K
H
C
O
3
+
K
O
H
Returning to the claim language, note that the claim does not require the first portion of base to be the same as the second portion of base, rather what it requires is that the first portion of base comprise a same base species as the second portion of base. Kaczur 2013 reads on the broadest reasonable interpretation of the claim language, despite the fact that Kaczur’s first base portion is different in composition than Kaczur’s second base portion, because Kaczur’s first and second base portions both comprise potassium hydroxide.
Applicant argues (Remarks pg 19-21) that the rejection of claims 6 and 27 is improper, because the prior art element that Examiner mapped onto claim 6’s “alkali metal salt” is potassium hydroxide. Applicant argues that a person working in the context of acid base chemistry would not call potassium hydroxide a salt, and would not consider the electrodialytic separation of potassium from formic acid to be a removal of a salt from an organic acid.
Applicant’s argument is unpersuasive because claims are treated according to their broadest reasonable interpretation in light of the specification. Examiner recognize that the instant specification considers alkali halide salts to be exemplary alkali metal salts (instant para [0059]). Potassium hydroxide is not an alkali halide. However, although the claims are interpreted in light of the specification, limitations from the specification are not read into the claims. See In re Van Geuns, 988 F.2d 1181, 26 USPQ2d 1057 (Fed. Cir. 1993). Potassium hydroxide is a salt of an alkali metal cation, so it reasonably reads on “alkali metal salt” (note that the instant disclosure itself calls potassium hydroxide an alkali metal salt at [0058]).
Conclusion
THIS ACTION IS MADE FINAL. Applicant is reminded of the extension of time policy as set forth in 37 CFR 1.136(a).
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/ANDREW KOLTONOW/Examiner, Art Unit 1795
/LUAN V VAN/Supervisory Patent Examiner, Art Unit 1795