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 .
Detailed Action
This office action is in response to applicant’s communication filed on 4/21/23.
Claims 1-12 are pending in this application and are being examined in this Office Action.
Priority
The applicant claims benefit as follows:
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Objections
Claim 1 is objected to because of the following informalities:
Claim 1 includes awkward and confusing claim language. The examiner requests the applicant clarify the wording of the claimed invention. For example, claim 1 recites “A DMF recycling method, for recycling DMF, acetic acid and water comprised in DMF stock solution used, is characterized in that, the method comprises the following steps:” The examiner recommends instead “A DMF recycling method for recycling a DMF stock solution containing DMF, acetic acid and water, comprising the following steps:“. Appropriate correction is required.
Claim Rejections – 35 USC 112.2
The following is a quotation of the second paragraph of 35 U.S.C. 112:
The specification shall conclude with one or more claims particularly pointing out and distinctly claiming the subject matter which the applicant regards as his invention.
Claims 3-4, 7-8 and 10-12 are rejected under 35 U.S.C. 112, second paragraph, as being indefinite for failing to particularly point out and distinctly claim the subject matter which applicant regards as the invention.
The claims are indefinite because of the claim language “preferably”. The specification doesn’t define the metes and bounds of "preferably", such that one would know what is included and what is excluded.
Claim 4 is indefinite because of the claim language “the amount of solute in the liquid alkali is 0.8 time to 1 time of the amount of substance of acetic acid”. It is unclear what applicant intends with the recitation ‘the amount of solute”? Is applicant referring to the molar or weight ratio of alkali to acetic acid?
Claim 12 is indefinite because of a lack of antecedent basis. Claim 12 recites “acid regulator”. However, claim 10, which claim 12 depends from, recites “acidic regulator”.
Appropriate correction is required.
Claim Rejections – 35 USC 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 of this title, 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 1-6, 8-9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (CN 108358807, pub date 8/3/2018, the English translation is used herein), in view of Li et al. (CN 108862795, pub date 11/23/2018, the English translation is used herein).
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
Wang et al. teaches a recycling method for dimethylformamide (DMF) wastewater, isolation of solid sodium acetate and recycling of the sodium acetate filtrate solution. Wang et al. exemplifies 7000 L of acidic DMF wastewater solution. 250 L of liquid alkali is added in the neutralization reaction and reacted for 2 hours. The reaction solution is then cooled and crystalized at 10 degree C for 2 hours. The crystalized mixture of sodium acetate is filtered. The filtrate which contains acidic DMF is evaporated in an evaporator at 70 – 75 degree C and a vacuum pressure of -.92 Kpa and -0.95 Kpa. DMF is distilled off from the acidic DMF solution in a distillation system in which the top temperature is 58-60 degree C and the vacuum pressure is -0.80 Kpa and -0.83 Kpa. This distilled DMF is recycled and reused. The filtrate from the sodium acetate crystallization is also recycled and reused to the decolorization kettle to dissolve the solid filtered sodium acetate, which is stirred for 1.5 hours during decolorization (paragraph 26-28 and claims)
Wang et al. goes on the exemplify the interconnectedness of the purification and recycling steps as follows: “The filtrate from the filter press enters the DMF filtrate receiving tank. The outlet of the DMF filtrate receiving tank is connected to the acidic DMF craped evaporator through a pipeline. The outlet of the acidic DMF scraped evaporator is connected to the DMF receiving tank. The outlet of the DMF receiving tank is connected to the DMF distillation system. The outlet of the DMF distillation system is connected to the finished product DMF receiving tank.” (paragraph 23)
It is reasonable to expect Wang et al.’s acidic DMF solution to contain acetic acid, which makes the solution acidic, since sodium acetate is formed when sodium hydroxide is added to neutralize the acetic acid.
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.012)
Wang et al. is deficient in that it does not teach controlling the pH, the extraction and layering step with an anti-solvent, the evaporation step of the two liquid layers made from the layering step and potassium carbonate as the alkali.
However, Li et al. teaches the following DMF recycling method. Li et al. teaches the recycling of DMF wastewater, adjusting the pH to 2-3, by ammonia, and to 6.4-6.7 with alkaline potassium carbonate. Filtering the solution to remove insoluble compounds. Then mixing the wastewater solution with an organic solvent, such as chloroform, dichloromethane and dichloroethane, to perform a countercurrent extraction with a volume ratio of organic solvent to wastewater of 1-2 : 1. The extracted wastewater is concentrated and evaporated, with recovery of the water and salt. The organic solution extract is distilled to recover both solvent and DMF separately, along with the water and the salt recovered separately. (abstract; paragraphs 9-15, 27)
Li et al. exemplifies using 2000 l of DMF wastewater, adjusting the pH to 2 with liquid ammonia, adding 500 l of potassium carbonate until the pH was between 6.4 and 6.7. Filtering the wastewater under vacuum. The filtrate of DMF and wastewater, was extracted with chloroform in an extraction tower at 1:1 volume ratio, to give DMF containing solution of chloroform and another solution of extracted wastewater. After distillation, chloroform at 60-65 degree C was collected, then DMF was collected at a pressure of -0.095 MPa. The evaporator then further extracts the wastewater to recover water and salts separately. (example 1, paragraphs 24-27)
It would be reasonable to expect Li et al.’s pH 6.7 value would read on applicant’s pH=7 limitation in claim 6, since it is standard to round up to pH 7 from pH 6.7 when reporting pH as a single significant digit, as in pH=7, which is claimed in applicant’s claim 6.
It would be reasonable to expect that two layers are formed, with one layer being the wastewater and the other layer containing the organic solvents, such as DMF and chloroform, since extractions are done by phase separating compounds, e.g. DMF, between immiscible two layer solutions, e.g. chloroform vs water, absent evidence to the contrary. Thus with regards to applicant’s limitation in claim 1 for layering the mother liquor containing the organic solvents, which include DMF and chloroform, in the upper liquid phase from the lower layer water liquid phase, it would be reasonable to expect the less dense organic solvent layers to be in the upper liquid phase and the denser water lawyer to be in the lower liquid phase, since phase separation of liquids is dependent on the density of the solvents. It would also be obvious to recycle the lower water layer to the DMF recycling, since the art teaches DMF wastewater recycling and since the lower water layer is a water discard from DMF extraction.
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
Furthermore, it would be prima facie obvious to one of ordinary skill in the art at the time of the invention, to substitute Li et al.’s potassium carbonate for Wang et al.’s liquid alkali, since potassium carbonate is a common basic alkali, and both Li et al. and Wang et al. use the alkali to neutralize the DMF wastewater. It would also be obvious to add the alkali as a solid or liquid, since both forms of are common and are an obvious optimization step.
With regard to applicant’s evaporation step in claim 1, it would be obvious to evaporate each of the liquid phases separately and concentrate them, which can then be recycled, since the art already teaches recycling of the extracted and purified liquid solutions, and in order to reuse the valuable solvents.
With regard to applicant’s recycling of the acetate hydrate solid, it would be obvious to also recycle the acetate hydrate solids, since Wang et al. teaches the crystallization of sodium acetate and the recycling of the sodium acetate filtrate solution, and in order to reuse valuable purified sodium acetate. It would also be reasonable to expect the sodium acetate to be in the hydrate form rather than the anhydrous from, since the acetate was isolated from an aqueous mixture and not from an anhydrous solvent.
Also with regard to applicant's limitations regarding the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent, it is the position of the examiner that one of ordinary skill in the art, at the time of the invention, would through routine and normal experimentation determine the optimization of these limitations to provide the best effective variable depending on the result desired. Because the art teaches DMF, water and acetic acid in the wastewater, stirring, temperature, reaction time, amount of alkali and anti-solvent the examiner asserts that the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent are art recognized result-effective variables. Thus it would be obvious in the optimization process to optimize the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent. The applicant does not show any unusual and/or unexpected results for the limitations stated. Note that the prior art provides the same effect desired by the Applicant, the recycling of DMF from DMF wastewater.
Additionally merely modifying process conditions such as temperature, time and concentration are not a patentable modification, absent a showing of criticality. In re Aller, 220 F.2d 454, 105 U.S.P.Q. 233 (C.C.P.A. 1955). Generally, differences in concentrations will not support the patentability of subject matter encompassed by the prior art. Such formulations are results-effective variables which can be optimized. In in re Boesch, 617 F.2d 272,276, 205 USPQ 215, 219 (CCPA 1980), it was held that "discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art." Further, in In re Alter, 220 F. 2d454, 456, 105 USPQ 233,235 (CCPA 1955) the courts maintained that: "Where the general condition of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."
Claim Rejections – 35 USC 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 of this title, 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 1-9 and 12 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (CN 108358807, pub date 8/3/2018, the English translation is used herein), in view of Li et al. (CN 108862795, pub date 11/23/2018, the English translation is used herein), further in view of Hu et al. (CN 106831472, pub date 6/13/2017, the English translation is used herein),
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
Wang et al. teaches a recycling method for dimethylformamide (DMF) wastewater, isolation of solid sodium acetate and recycling of the sodium acetate filtrate solution. Wang et al. exemplifies 7000 L of acidic DMF wastewater solution. 250 L of liquid alkali is added in the neutralization reaction and reacted for 2 hours. The reaction solution is then cooled and crystalized at 10 degree C for 2 hours. The crystalized mixture of sodium acetate is filtered. The filtrate which contains acidic DMF is evaporated in an evaporator at 70 – 75 degree C and a vacuum pressure of -.92 Kpa and -0.95 Kpa. DMF is distilled off from the acidic DMF solution in a distillation system in which the top temperature is 58-60 degree C and the vacuum pressure is -0.80 Kpa and -0.83 Kpa. This distilled DMF is recycled and reused. The filtrate from the sodium acetate crystallization is also recycled and reused to the decolorization kettle to dissolve the solid filtered sodium acetate, which is stirred for 1.5 hours during decolorization (paragraph 26-28 and claims)
Wang et al. goes on the exemplify the interconnectedness of the purification and recycling steps as follows: “The filtrate from the filter press enters the DMF filtrate receiving tank. The outlet of the DMF filtrate receiving tank is connected to the acidic DMF craped evaporator through a pipeline. The outlet of the acidic DMF scraped evaporator is connected to the DMF receiving tank. The outlet of the DMF receiving tank is connected to the DMF distillation system. The outlet of the DMF distillation system is connected to the finished product DMF receiving tank.” (paragraph 23)
It is reasonable to expect Wang et al.’s acidic DMF solution to contain acetic acid, which makes the solution acidic, since sodium acetate is formed when sodium hydroxide is added to neutralize the acetic acid.
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.012)
Wang et al. is deficient in that it does not teach controlling the pH, the extraction and layering step with an anti-solvent, the evaporation step of the two liquid layers made from the layering step and potassium carbonate as the alkali.
However, Li et al. teaches the following DMF recycling method. Li et al. teaches the recycling of DMF wastewater, adjusting the pH to 2-3, by ammonia, and to 6.4-6.7 with alkaline potassium carbonate. Filtering the solution to remove insoluble compounds. Then mixing the wastewater solution with an organic solvent, such as chloroform, dichloromethane and dichloroethane, to perform a countercurrent extraction with a volume ratio of organic solvent to wastewater of 1-2 : 1. The extracted wastewater is concentrated and evaporated, with recovery of the water and salt. The organic solution extract is distilled to recover both solvent and DMF separately, along with the water and the salt recovered separately. (abstract; paragraphs 9-15, 27)
Li et al. exemplifies using 2000 l of DMF wastewater, adjusting the pH to 2 with liquid ammonia, adding 500 l of potassium carbonate until the pH was between 6.4 and 6.7. Filtering the wastewater under vacuum. The filtrate of DMF and wastewater, was extracted with chloroform in an extraction tower at 1:1 volume ratio, to give DMF containing solution of chloroform and another solution of extracted wastewater. After distillation, chloroform at 60-65 degree C was collected, then DMF was collected at a pressure of -0.095 MPa. The evaporator then further extracts the wastewater to recover water and salts separately. (example 1, paragraphs 24-27)
It would be reasonable to expect Li et al.’s pH 6.7 value would read on applicant’s pH=7 limitation in claim 6, since it is standard to round up to pH 7 from pH 6.7 when reporting pH as a single significant digit, as in pH=7, which is claimed in applicant’s claim 6.
It would be reasonable to expect that two layers are formed, with one layer being the wastewater and the other layer containing the organic solvents, such as DMF and chloroform, since extractions are done by phase separating compounds, e.g. DMF, between immiscible two layer solutions, e.g. chloroform vs water, absent evidence to the contrary. Thus with regards to applicant’s limitation in claim 1 for layering the mother liquor containing the organic solvents, which include DMF and chloroform, in the upper liquid phase from the lower layer water liquid phase, it would be reasonable to expect the less dense organic solvent layers to be in the upper liquid phase and the denser water lawyer to be in the lower liquid phase, since phase separation of liquids is dependent on the density of the solvents. It would also be obvious to recycle the lower water layer to the DMF recycling, since the art teaches DMF wastewater recycling and since the lower water layer is a water discard from DMF extraction.
Wang et al. and Li et al. are also deficient in that it does not teach applicant’s anti-solvent of benzene for the extraction in claim 7. Instead, Li et al. teaches the chlorinated solvents, such as chloroform and dichloromethane, are used for the extraction.
Hu et al. teaches a DMF recycling system that separately recover inorganic salts, DMF and the extraction agent. Acid or alkali is added to neutralize the DMF solution to make it neutral, in which salt is generated. An organic extractant such as petroleum ether, dichloromethane or benzene is added to the solution to leach DMF from the waste liquid, then filtering off a solid. This DMF extractant mixture is distilled to separately obtain the organic extractant and DMF. The mass ratio of organic extractant to the liquid is 5-20 : 1. After adding the organic extractant, a layered mixture of solvent and solid is obtained, which is filtered to remove the salt solids and an organic extractant-DMF mixture. (paragraph 4, 13-16, examples and claims)
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
Thus, it would be prima facie obvious to one of ordinary skill in the art at the time of the invention, to substitute Hu et al.’s organic solvent extractant, benzene, with Li et al.’s chlorinated organic solvent extractants, chloroform and dichloromethane, since these extractants are taught to extract DMF from the wastewater, and especially to avoid the use of chlorinated solvents. Thus since Hu et al. teaches the use of dichloromethane and benzene and Li et al. teaches the use of dichloromethane and chloroform, the art teaches the equivalency of using dichloromethane, benzene and chloroform as extractants (or as an anti-solvent in claim 7), for DMF recovery. The examiner notes that applicant’s anti-solvent is used as a solvent to extract DMF (see claim 1).
In other words, it would be obvious to use Hu et al.’s benzene extractant (applicant’s anti-solvent in claim 7), instead of Li et al.’s dichloromethane and chloroform. Thus, at the time of instant invention, a person of ordinary skill in the art would have been motivated to substitute Li et al.’s dichloromethane and chloroform with Hu et al.’s benzene, with a reasonable expectation of success for extraction of DMF from wastewater. Note that an express suggestion to substitute one equivalent component or process for another is not necessary to render such substitution obvious. In re Fout, 675 F.2d 297, 213 USPQ 532 (CCPA 1982).
Furthermore, it would be prima facie obvious to one of ordinary skill in the art at the time of the invention, to substitute Li et al.’s potassium carbonate for Wang et al.’s liquid alkali, since potassium carbonate is a common basic alkali, and both Li et al. and Wang et al. use the alkali to neutralize the DMF wastewater. It would also be obvious to add the alkali as a solid or liquid, since both forms of are common and are an obvious optimization step.
With regard to applicant’s evaporation step in claim 1, it would be obvious to evaporate each of the liquid phases separately and concentrate them, which can then be recycled, since the art already teaches recycling of the extracted and purified liquid solutions, and in order to reuse the valuable solvents.
With regard to applicant’s recycling of the acetate hydrate solid, it would be obvious to also recycle the acetate hydrate solids, since Wang et al. teaches the crystallization of sodium acetate and the recycling of the sodium acetate filtrate solution, and in order to reuse valuable purified sodium acetate. It would also be reasonable to expect the sodium acetate to be in the hydrate form rather than the anhydrous from, since the acetate was isolated from an aqueous mixture and not from an anhydrous solvent.
Also with regard to applicant's limitations regarding the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent, it is the position of the examiner that one of ordinary skill in the art, at the time of the invention, would through routine and normal experimentation determine the optimization of these limitations to provide the best effective variable depending on the result desired. Because the art teaches DMF, water and acetic acid in the wastewater, stirring, temperature, reaction time, amount of alkali and anti-solvent the examiner asserts that the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent are art recognized result-effective variables. Thus it would be obvious in the optimization process to optimize the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent. The applicant does not show any unusual and/or unexpected results for the limitations stated. Note that the prior art provides the same effect desired by the Applicant, the recycling of DMF from DMF wastewater.
Additionally merely modifying process conditions such as temperature, time and concentration are not a patentable modification, absent a showing of criticality. In re Aller, 220 F.2d 454, 105 U.S.P.Q. 233 (C.C.P.A. 1955). Generally, differences in concentrations will not support the patentability of subject matter encompassed by the prior art. Such formulations are results-effective variables which can be optimized. In in re Boesch, 617 F.2d 272,276, 205 USPQ 215, 219 (CCPA 1980), it was held that "discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art." Further, in In re Alter, 220 F. 2d454, 456, 105 USPQ 233,235 (CCPA 1955) the courts maintained that: "Where the general condition of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."
Claim Rejections – 35 USC 103
In the event the determination of the status of the application as subject to AIA 35 U.S.C. 102 and 103 (or as subject to pre-AIA 35 U.S.C. 102 and 103) is incorrect, any correction of the statutory basis for the rejection will not be considered a new ground of rejection if the prior art relied upon, and the rationale supporting the rejection, would be the same under either status.
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 of this title, 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 1-6 and 8-12 are rejected under 35 U.S.C. 103 as being unpatentable over Wang et al. (CN 108358807, pub date 8/3/2018, the English translation is used herein), in view of Li et al. (CN 108862795, pub date 11/23/2018, the English translation is used herein), further in view of Wu et al. (CN 110639354, pub date 1/3/2020, the English translation is used herein),
Determination of the Scope and Content of the Prior Art
(MPEP §2141.01)
Wang et al. teaches a recycling method for dimethylformamide (DMF) wastewater, isolation of solid sodium acetate and recycling of the sodium acetate filtrate solution. Wang et al. exemplifies 7000 L of acidic DMF wastewater solution. 250 L of liquid alkali is added in the neutralization reaction and reacted for 2 hours. The reaction solution is then cooled and crystalized at 10 degree C for 2 hours. The crystalized mixture of sodium acetate is filtered. The filtrate which contains acidic DMF is evaporated in an evaporator at 70 – 75 degree C and a vacuum pressure of -.92 Kpa and -0.95 Kpa. DMF is distilled off from the acidic DMF solution in a distillation system in which the top temperature is 58-60 degree C and the vacuum pressure is -0.80 Kpa and -0.83 Kpa. This distilled DMF is recycled and reused. The filtrate from the sodium acetate crystallization is also recycled and reused to the decolorization kettle to dissolve the solid filtered sodium acetate, which is stirred for 1.5 hours during decolorization (paragraph 26-28 and claims)
Wang et al. goes on the exemplify the interconnectedness of the purification and recycling steps as follows: “The filtrate from the filter press enters the DMF filtrate receiving tank. The outlet of the DMF filtrate receiving tank is connected to the acidic DMF craped evaporator through a pipeline. The outlet of the acidic DMF scraped evaporator is connected to the DMF receiving tank. The outlet of the DMF receiving tank is connected to the DMF distillation system. The outlet of the DMF distillation system is connected to the finished product DMF receiving tank.” (paragraph 23)
It is reasonable to expect Wang et al.’s acidic DMF solution to contain acetic acid, which makes the solution acidic, since sodium acetate is formed when sodium hydroxide is added to neutralize the acetic acid.
Ascertainment of the Difference Between Scope the Prior Art and the Claims
(MPEP §2141.012)
Wang et al. is deficient in that it does not teach controlling the pH, the extraction and layering step with an anti-solvent, the evaporation step of the two liquid layers made from the layering step and potassium carbonate as the alkali.
However, Li et al. teaches the following DMF recycling method. Li et al. teaches the recycling of DMF wastewater, adjusting the pH to 2-3, by ammonia, and to 6.4-6.7 with alkaline potassium carbonate. Filtering the solution to remove insoluble compounds. Then mixing the wastewater solution with an organic solvent, such as chloroform, dichloromethane and dichloroethane, to perform a countercurrent extraction with a volume ratio of organic solvent to wastewater of 1-2 : 1. The extracted wastewater is concentrated and evaporated, with recovery of the water and salt. The organic solution extract is distilled to recover both solvent and DMF separately, along with the water and the salt recovered separately. (abstract; paragraphs 9-15, 27)
Li et al. exemplifies using 2000 l of DMF wastewater, adjusting the pH to 2 with liquid ammonia, adding 500 l of potassium carbonate until the pH was between 6.4 and 6.7. Filtering the wastewater under vacuum. The filtrate of DMF and wastewater, was extracted with chloroform in an extraction tower at 1:1 volume ratio, to give DMF containing solution of chloroform and another solution of extracted wastewater. After distillation, chloroform at 60-65 degree C was collected, then DMF was collected at a pressure of -0.095 MPa. The evaporator then further extracts the wastewater to recover water and salts separately. (example 1, paragraphs 24-27)
It would be reasonable to expect Li et al.’s pH 6.7 value would read on applicant’s pH=7 limitation in claim 6, since it is standard to round up to pH 7 from pH 6.7 when reporting pH as a single significant digit, as in pH=7, which is claimed in applicant’s claim 6.
It would be reasonable to expect that two layers are formed, with one layer being the wastewater and the other layer containing the organic solvents, such as DMF and chloroform, since extractions are done by phase separating compounds, e.g. DMF, between immiscible two layer solutions, e.g. chloroform vs water, absent evidence to the contrary. Thus with regards to applicant’s limitation in claim 1 for layering the mother liquor containing the organic solvents, which include DMF and chloroform, in the upper liquid phase from the lower layer water liquid phase, it would be reasonable to expect the less dense organic solvent layers to be in the upper liquid phase and the denser water lawyer to be in the lower liquid phase, since phase separation of liquids is dependent on the density of the solvents. It would also be obvious to recycle the lower water layer to the DMF recycling, since the art teaches DMF wastewater recycling and since the lower water layer is a water discard from DMF extraction.
Wang et al. and Li et al. are also deficient in that it does not teach applicant’s acid regulator of sulfuric acid, and pH adjustment to pH 6-8, in claims 10 and 11. Instead Li et al. teaches pH adjustment to pH 6.4 - 6.7.
Wu et al. teaches a DMF wastewater recovery and recycling system, in which sequential washing by alkali, acid and clear water is used to remove impurities, DMF and other low-boiling matter. After pH adjustment, the discharged acid solution and the alkali solution are returned to the DMF wastewater recovery system. The invention includes an alkali washing step and an acid washing step. The alkali washing solution can be a 5-32% sodium hydroxide aqueous solution, and the acid washing solution can be a 5-30% sulfuric acid or hydrochloric acid aqueous solution. (page 7, 4th paragraph; claims)
Finding of Prima Facie Obviousness Rationale and Motivation
(MPEP §2142-2143)
Therefore it would be prima facie obvious to one of ordinary skill in the art at the time of the invention, to use Wu et al.’s sulfuric acid and sodium hydroxide for pH adjustment, especially since both Wang et al. and Li et al. teach the need for neutralization of the DMF wastewater and Li teaches pH adjustment to pH 6.4 - 6.7, which is a neutral pH. Using the common acid and base, such as sulfuric acid and sodium hydroxide to neutralize the DMF wastewater is an obvious optimization step.
Furthermore, it would be prima facie obvious to one of ordinary skill in the art at the time of the invention, to substitute Li et al.’s potassium carbonate for Wang et al.’s liquid alkali, since potassium carbonate is a common basic alkali, and both Li et al. and Wang et al. use the alkali to neutralize the DMF wastewater. It would also be obvious to add the alkali as a solid or liquid, since both forms of are common and are an obvious optimization step.
With regard to applicant’s evaporation step in claim 1, it would be obvious to evaporate each of the liquid phases separately and concentrate them, which can then be recycled, since the art already teaches recycling of the extracted and purified liquid solutions, and in order to reuse the valuable solvents.
With regard to applicant’s recycling of the acetate hydrate solid, it would be obvious to also recycle the acetate hydrate solids, since Wang et al. teaches the crystallization of sodium acetate and the recycling of the sodium acetate filtrate solution, and in order to reuse valuable purified sodium acetate. It would also be reasonable to expect the sodium acetate to be in the hydrate form rather than the anhydrous from, since the acetate was isolated from an aqueous mixture and not from an anhydrous solvent.
Also with regard to applicant's limitations regarding the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent, it is the position of the examiner that one of ordinary skill in the art, at the time of the invention, would through routine and normal experimentation determine the optimization of these limitations to provide the best effective variable depending on the result desired. Because the art teaches DMF, water and acetic acid in the wastewater, stirring, temperature, reaction time, amount of alkali and anti-solvent the examiner asserts that the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent are art recognized result-effective variables. Thus it would be obvious in the optimization process to optimize the % mass content, temperature, stirring rate, reaction and stirring time, amount of solid/liquid alkali and anti-solvent. The applicant does not show any unusual and/or unexpected results for the limitations stated. Note that the prior art provides the same effect desired by the Applicant, the recycling of DMF from DMF wastewater.
Additionally merely modifying process conditions such as temperature, time and concentration are not a patentable modification, absent a showing of criticality. In re Aller, 220 F.2d 454, 105 U.S.P.Q. 233 (C.C.P.A. 1955). Generally, differences in concentrations will not support the patentability of subject matter encompassed by the prior art. Such formulations are results-effective variables which can be optimized. In in re Boesch, 617 F.2d 272,276, 205 USPQ 215, 219 (CCPA 1980), it was held that "discovery of an optimum value of a result effective variable in a known process is ordinarily within the skill of the art." Further, in In re Alter, 220 F. 2d454, 456, 105 USPQ 233,235 (CCPA 1955) the courts maintained that: "Where the general condition of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation."
Conclusion
No claims are allowed.
Any inquiry concerning this communication or earlier communications from the examiner should be directed to Jennifer Cho Sawyer whose telephone number is (571) 270 1690. The examiner can normally be reached on Monday-Friday 9 AM - 6 PM PST.
If attempts to reach the examiner by telephone are unsuccessful, the examiner's supervisor, Renee Claytor can be reached on (571) 272-8394. The fax phone number for the organization where this application or proceeding is assigned is 571-274-1690.
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Jennifer Cho Sawyer
Patent Examiner
Art Unit: 1691
/RENEE CLAYTOR/Supervisory Patent Examiner, Art Unit 1691