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
Claims 1 and 3-19 of Keyes, Timothy H., US 17/772,271 (04/27/2022) are pending, under examination on merits and are rejected.
Withdrawal of Office Action Finality
A request for continued examination of US 17/772,271 under 37 CFR 1.114, including the fee set forth in 37 CFR 1.17(e), was filed in this application after final rejection. Since this application is eligible for continued examination under 37 CFR 1.114, and the fee set forth in 37 CFR 1.17(e) has been timely paid, the finality of the previous Office action has been withdrawn pursuant to 37 CFR 1.114. Applicant's submission filed on 12/10/2025 has been entered.
Claim Interpretation and Summary
During examination, a claim must be given its broadest reasonable interpretation consistent with the specification as it would be interpreted by one of ordinary skill in the art. MPEP § 2173.01(I); § 2111.01. Under a broadest reasonable interpretation, words of the claim must be given their plain meaning, unless such meaning is inconsistent with the specification. The plain meaning of a term means the ordinary and customary meaning given to the term by those of ordinary skill in the art at the time of the invention. MPEP § 2173.01(I).
Interpretation of the Claim 1 Reaction Components and Product
Claim 1 recites the step of:
1. . . oxidizing in a reactor zone a feedstock comprising a substituted aromatic hydrocarbon in the presence of an oxidation catalyst and monocarboxylic acid solvent to form crude aromatic carboxylic acid . . .
With respect to the meaning of “substituted aromatic hydrocarbon”, the specification teaches that:
[0035] As described above, the feedstock includes a substituted aromatic hydrocarbon. Representative feedstock materials suitable for use in the processes of the disclosure include but are not limited to aromatic hydrocarbons substituted at one or more positions with at least one substituent that is oxidizable to a carboxylic acid group. In some embodiments, the positions of the substituents correspond to the positions of the carboxylic acid groups of the aromatic carboxylic acid being prepared.
Specification at page 5, [0035] (emphasis added). In view of the specification, the term “substituted aromatic hydrocarbon” is broadly and reasonably interpreted as any compound comprising at least an aromatic hydrocarbon group, such as a benzene ring, and at least a group that is oxidizable to a carboxylic acid group by way of an oxidation catalyst, where the oxidizable substituent need not be directly bonded to the aromatic hydrocarbon.
The specification does not define “oxidation catalyst”. The claim 1 term “oxidation catalyst” is broadly and reasonably interpreted as any catalyst that can oxidize a group to a carboxylic acid group.
The specification does not define or limit the solvent that is the “monocarboxylic acid solvent”.
Interpretation of the Claim Terms of “reactor zone”, “filter zone”, and “recovery zone
The claims recite the limitation of the term of “reactor zone”, “filter zone”, and/or “recovery zone”. The specification does not give definition for the term of “reactor zone”, “filter zone”, or “recovery zone”. According to their plain meanings, the term “reactor zone” is broadly and reasonably interpreted as any site/location/position where a reaction is conducted; the term “filter zone” is broadly and reasonably interpreted as any site/location/position where a filtration is conducted; the term “recovery zone” is broadly and reasonably interpreted as any site/location/position where a recovery is conducted.
Interpretation of the Claim Language of “the filter cake of a compartment becomes more compressed as the compartment rotates, so that the amount of solids forced through the filter member decreases”
Claim scope is not limited by claim language that suggests or makes optional but does not require steps to be performed, or by claim language that does not limit a claim to a particular structure. MPEP § 2111.04 (citing In Hoffer v. Microsoft Corp., 405 F.3d 1326, 1329, 74 USPQ2d 1481, 1483 (Fed. Cir. 2005). In the instant case, recitation of the language of
Claim 1 . . . the filter cake of a compartment becomes more compressed as the compartment rotates, so that the amount of solids forced through the filter member decreases . . .
does not change any the claimed active steps in the claimed process. The court noted that a "‘whereby clause in a method claim is not given weight when it simply expresses the intended result of a process step positively recited.’" Id. (quoting Minton v. Nat’l Ass’n of Securities Dealers, Inc., 336 F.3d 1373, 1381, 67 USPQ2d 1614, 1620 (Fed. Cir. 2003)). Herein, the citation of “the filter cake of a compartment becomes more compressed as the compartment rotates, so that the amount of solids forced through the filter member decreases” is not a require step , but rather simply expresses the intended result of a process step positively recited, therefore, is not given weight for patentability.
Interpretation of the Claim Language of “separate feed filtrates from different filter zones of the rotary pressure filter”
The instant claim 1 recites the claim language of “separate feed filtrates from different filter zones of the rotary pressure filter” in the follows context:
A process for manufacturing an aromatic carboxylic acid comprising
. . . . ;
filtering the solid/liquid mixture in a feed zone of a rotary pressure filter, the rotary pressure filter comprising a plurality of compartments each having a filter member, the feed zone having at least two filter zones, wherein the filtering forms a filter cake on a filter member of a compartment and the filter cake of a compartment becomes more compressed as the compartment rotates, so that the amount of solids forced through the filter member decreases,
collecting separate feed filtrates from different filter zones of the rotary pressure filter, the separate feed filtrates comprising
a first feed filtrate comprising monocarboxylic acid solvent and solids; and
a second feed filtrate separate from the first feed filtrate, . . . .
. . . ..
The specification discusses the closest information as:
[0062] Filtrate from compartments 332 is removed from the rotary pressure filter apparatus 300 through outlet pipes 336 and delivered into filter zones 364 that do not rotate with the filter drum 306. In certain embodiments, filtrate from outlet pipes 336 is collected in six filter zones, 364a, 364b, 364c, 364d, 364e, and 364f.
[0063] The circumference of the rotary pressure apparatus 300 defines a 360° work path, with each filter zone 364 associated with a portion of the work path. In the embodiment shown in FIG. 5, filtrate from compartments 332 located in a first portion of feed zone 324a will be delivered through outlet pipes 336 into filter zone 364a, and removed from the rotary pressure filter apparatus 300 through outlet piping 360a, and filtrate from compartments 332 located in a second portion of feed zone 324a will be delivered through outlet pipes 336 into filter zone 364b, and removed from the rotary pressure filter apparatus 300 through outlet piping 360b. . . ..
Specification at page 13, [0062]-[0063], emphasis added.
Consistent with the information disclosed in the specification, the claim language of “separate feed filtrates from different filter zones of the rotary pressure filter” is broadly and reasonably interpreted as different filtrates produced through filtration of the solid/liquid mixture at different filter zones of a rotary pressure filter, each of the different filtrates comprises
a first feed filtrate comprising monocarboxylic acid solvent and solids; and
a second feed filtrate comprising monocarboxylic acid solvent and solids;
the second feed filtrate being lower in solids than the first feed filtrate.
Claim Rejections - 35 USC § 103
The following is a quotation of 35 U.S.C. 103 which forms the basis for all obviousness rejections set forth in this Office action:
A patent for a claimed invention may not be obtained, notwithstanding that the claimed invention is not identically disclosed as set forth in section 102, if the differences between the claimed invention and the prior art are such that the claimed invention as a whole would have been obvious before the effective filing date of the claimed invention to a person having ordinary skill in the art to which the claimed invention pertains. Patentability shall not be negated by the manner in which the invention was made.
The factual inquiries for establishing a background for determining obviousness under 35 U.S.C. 103 are summarized as follows:
1. Determining the scope and contents of the prior art.
2. Ascertaining the differences between the prior art and the claims at issue.
3. Resolving the level of ordinary skill in the pertinent art.
4. Considering objective evidence present in the application indicating obviousness or non-obviousness.
Note: the 103 Rejections made in the previous Office action are modified by reorganizing the teachings from Larsen, Zaima and Bartos according to the claim amendment and Applicant’s arguments with Wakenman as an additional art to emphasize the motivation to collect two different filtrates.
Claims 1and 3-19 are rejected under 35 U.S.C. 103 as being unpatentable over A. Bitsch-Larsen, et al, WO2019019012A1 (published on 01/31/2019)(“Larsen”) in view of T. Bartos, et al, WO2016014830 A1 (2016)(“Bartos”); R. Wakeman, 58(2) Separation and purification technology 234-241(2007)(“Wakeman”); and F. Zaima, et al, US20100016629A1 (2010)( “Zaima”).
A. Bitsch-Larsen, et al, WO2019019012A1 (published on 01/31/2019)(“Larsen”)
Larsen teaches that terephthalic acid (TA) and other aromatic carboxylic acids may be used in the manufacture of polyesters. Larsen at page 1, Background, line 1-2.
Larsen teaches a process for manufacturing and recovering purified forms of aromatic carboxylic acids such as terephthalic acid as indicated the following Fig. 1.
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Larsen at page 4, paragraph 2, line 1-3 and Fig.1.
Larsen teaches that:
As a brief introduction, the process 100 includes a reaction zone comprising an oxidation reactor 110 configured for liquid phase oxidation of feedstock; a crystallization zone configured for forming crude aromatic carboxylic acid from the liquid phase oxidation reaction mixture， and comprising crystallization vessels 152 and 156; a solid-liquid separation device 190 configured for separating crude aromatic carboxylic acid (and oxidation by-products) from liquid.
Larsen at page 4, paragraph 2, line 3-8, emphasis added.
With regards to the reaction zone comprising a oxidation reactor 110, Larsen teaches that:
A representative type of oxidation that may be conducted in the oxidation reactor 110 is a liquid phase oxidation that comprises contacting oxygen gas and a feed material comprising an aromatic hydrocarbon having substituents oxidizable to carboxylic acid groups in a liquid phase reaction mixture. In some embodiments， the liquid phase reaction mixture comprises a monocarboxylic acid solvent and water in the presence of a catalyst composition comprising at least one heavy metal component (e.g.， Co， Mn， V， Mo， Cr， Fe， Ni， Zi， Ce， Hf， or the like， and combinations thereof) and a promoter (e.g.， halogen compounds， etc. ).
Larsen at page 6, paragraph 3, line 1-7, emphasis added.
Thus, Larsen teaches the claim 1 limitation step of:
oxidizing in a reactor zone a feedstock comprising a substituted aromatic hydrocarbon in the presence of an oxidation catalyst and monocarboxylic acid solvent to form crude aromatic carboxylic acid.
With regards to the crystallization zone, Larsen teaches that:
the crystallization process comprises sequential reductions in temperature and pressure from earlier to later stages to increase product recovery. By way of example， as shown in FIG. 1， crystallization vessels 152 and 156 may be provided in series and in fluid communication， such that product slurry from vessel 152 may be transferred to vessel 156. Cooling in the crystallization vessels may be accomplished by pressure release. One or more of the crystallization vessels may be vented， as at vents 154 and 158， to remove vapor resulting from pressure let down and generation of steam from the flashed vapor to a heat exchange means (not shown).
Larsen at page 8, paragraph 3, line 4-11, emphasis added.
Thus, Larsen teaches the claim 1 limitation step of:
cooling the reactor zone effluent to form a solid/liquid mixture comprising a solid crude aromatic carboxylic acid, a monocarboxylic acid solvent, and the oxidation catalyst.
With regards to the solid-liquid separation, Larsen teaches that:
As shown in FIG. 1, the crystallization vessel 156 is in fluid communication with a solid-liquid separation device 190. The solid-liquid separation device 190 is configured to receive a slurry of solid product from the crystallization vessel 156. In some embodiments， the solid-liquid separation device 190 is further configured to separate a crude solid product and by-products from the liquid. . . . the separation device 190 comprises a pressure filter configured for solvent exchange (e.g.， by positive displacement under pressure of mother liquor in a filter cake with wash liquid comprising water). Suitable rotary pressure filters are sold by BHS-Sonthofen and are disclosed for example, in US Pat Nos. 2,741,369， 7,807,060， US Pat. App. 20050051473， US Pat. App. 20150182890， and WO2016014830. The oxidation mother liquor resulting from the separation may exit separation device 190 in stream 191 for transfer to mother liquor drum 192. A portion of the mother liquor and， in some embodiments, a major portion of the mother liquor, may be transferred from drum 192 to oxidation reactor 110. In such a way, monocarboxylic acid solvent， water， catalyst， and/or oxidation reaction by-products dissolved and/or present as fine solid particles in the mother liquor may be returned to the liquid phase oxidation reaction.
Larsen at page 8, paragraph 4, line 1 to page 9, paragraph 1; emphasis added.
Thus, Larsen also teaches the claim 1 limitation step of :
filtering the solid/liquid mixture in a feed zone of a rotary pressure filter, wherein the filtering forms a filter cake on a filter member of a compartment and transferring at least a portion of the filtrate to the reactor zone as recycle.
To summarize, Larsen teaches a process for manufacturing and recovering purified forms of aromatic carboxylic acids comprises:
(i). oxidizing in a reactor zone a feedstock comprising a substituted aromatic hydrocarbon in the presence of an oxidation catalyst and monocarboxylic acid solvent to form crude aromatic carboxylic acid;
(ii). cooling the reactor zone effluent to form a solid/liquid mixture comprising a solid crude aromatic carboxylic acid, a monocarboxylic acid solvent, and minor amounts of the oxidation catalyst;
(iii). filtering the solid/liquid mixture in a feed zone of a rotary pressure filter;
(iv). transferring at least a portion of the filtrate to the reactor zone as recycle.
Difference between Larsen and the Claims
Larsen differs from the instant claim 1 in that Larsen does not teach:
(i). collecting separate feed filtrates from different filter zones of the rotary pressure filter, the separate feed filtrates comprising a first feed filtrate comprising monocarboxylic acid solvent and solids; and a second feed filtrate separate from the first feed filtrate, the second feed filtrate comprising monocarboxylic acid solvent and solids, the second feed filtrate being lower in solids than the first feed filtrate;
(ii). transferring the second feed filtrate to a catalyst recovery zone;
(ii).recovering oxidation catalyst from the second feed filtrate in the catalyst recovery zone to provide an effluent that is poor in catalyst; or
(iv).purging a portion of the effluent that is poor in catalyst
T. Bartos, et al, WO2016014830 A1 (2016)(“Bartos”)
Bartos teaches that multiple-stage separation techniques may result in higher purities of solid products, but may require substantially more investment in equipment. One highly successful method to reduce capital expenditures in a multi-stage separation is through the use of a rotary pressure filter apparatus. Rotary pressure filter apparatus have been designed to perform more than one of the steps of a multiple-stage separation technique in a single piece of equipment by progressing the material being processed through separate work zones. For example, known rotary pressure filter apparatus perform a filtration in a filter or feed zone to form a filter cake, followed by a washing of the filter cake in one or more wash zones. Bartos at page 1, [0003], line 1-9, emphasis added.
Bartos teaches a rotary pressure filter apparatus having greater capacity and improved lifespan for the filter elements. Bartos at page 2, [0006]. Per Figure 2, Bartos teaches the front view cross-section structure of the rotary pressure filter apparatus as indicated below. Bartos at Fig. 2, and page 5-6, [0023]-[0024].
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Bartos teaches that:
[0025] Referring now to FIG. 3, a plurality of compartments 132 are arranged around the outer surface or circumference of the rotary filter drum 106 and rotate with the filter drum 106. The compartments 132 each include a filter member 134 (shown in one compartment in FIG.3) adjacent the filter drum. In some embodiments the filter member comprises a filter cloth supported over a metal screen in a filter housing (not shown). In some embodiments, the filter cloth is manufactured from a polyether ether ketone (PEEK) polymer or a polyvinylidene difluoride (PVDF) polymer. Each compartment 132 also has associated with it a corresponding outlet pipe 136 which also rotates with the filter drum 106 and the compartments 118. The outlet pipes 136 are configured such that filtrate received each compartment 118 passes through its corresponding filter member 134 adjacent the filter drum 106 and into its corresponding outlet pipe 136. The outlet pipes 136 remove the filtrate from the compartments 132 and deliver the filtrate to the control head 116, where it is collected through additional piping (not shown) and removed from the rotary pressure filter apparatus 100.
Bartos at page 6, [0025], emphasis added.
Bartos teaches that:
[0027] In operation, a pressurized feed containing a solid-liquid mixture is introduced into the feed inlet material passageway 120a and into plenum 118 in a first zone designated as feed zone 124a. The solid-liquid mixture is distributed into compartments 132. In some embodiments, the pressure in the feed zone is maintained at about 3 bar(g) to about 7 bar(g), and in some embodiments, 5 bar(g) to 6 bar(g). As a result of the pressure differential that is maintained between the compartments 132 and the outlet pipes 136 and across the filter member 134 in the compartments, liquid of the solid-liquid mixture is forced through the filter member 134 into outlet pipes 136. Filtrate thus exits the rotary pressure apparatus 100 through outlet pipes 136. The solid components of the solid-liquid mixture remain on the filter members 134 in the form of a filter cake.
Bartos at page 6, [0027], emphasis added.
Thus Bartosteaches that a filter cake would be formed during the filtration with the rotary pressure filter apparatus.
Bartos teaches that:
[0040] The rotary pressure filter apparatus 100 may be used in a variety of separation processes. In some embodiments, the rotary pressure filter apparatus 100 is used to recover a solid product, or a liquid, or both, from a solid/liquid mixture. The solid is recovered from the apparatus as a filter cake that is formed on the filter members 134. The filtrate is recovered through outlet pipes 136. In one embodiment, the solid is a petrochemical, such as an aromatic carboxylic acid.
[0041] In one particular embodiment, the solid product is a crude terephthalic acid product and the liquid includes a solvent containing acetic acid. The crude terephthalic acid is recovered as a filter cake exiting the material passageway 120e. The solvent is recovered as filtrate exiting outlet pipes 136..
Bartos at page 10, [0040]-[0041], emphasis added.
While the Figure of Bartos indicate the rotary pressure filter apparatus have only one filtration zone in a feed zone, however, Bartos teaches that :
[0031] Those skilled in the art will appreciate that other configurations of the rotary pressure filter apparatus 100 may be used in accordance with the present invention. For example, the rotary pressure filter apparatus 100 may include multiple filtering zones and multiple wash zones.
Bartos at page 7, [0031], emphasis added.
Thus, Bartos teaches one ordinary skill that his rotary pressure filter apparatus can be modified by including multiple filtering zones and the modified rotary pressure filter apparatus can be used to recover solid crude terephthalic acid product and filtrates; which meets the claim 1 limitation of:
collecting separate feed filtrates from different filter zones of the rotary pressure filter.
R. Wakeman, 58(2) Separation and purification technology 234-241 (2007)(“Wakeman”)
Wakeman studied the influence of particle properties on filtration and teaches mechanisms of filtration as follow:
Filter media retain particles in two principal ways. When particles are predominantly larger than the sizes of the pores in the filter medium, they form a deposit on the medium surface (the filter cake). When particles are generally smaller than the pores sizes in a filter medium, deposition occurs within the internal structure of the medium (some very small particles may pass through the medium and be collected in the filtrate). This process of separation may be due to mechanical or surface chemical effects and is referred to as depth filtration and is the modus operandi of, for example, deep bed sand filters and some types of cartridge filters. In these applications the concentration of solids in the feed is usually very low, enabling particles to pass relatively unhindered into pores by following the trajectory of fluid streamlines. The principle of depth filtration is illustrated in Fig. 1a.
At the microscopic scale cake filtration is achieved by a combination of two primary mechanisms, complete blocking shown in Fig. 1b (a sieving process that occurs when the particles are larger than the pore sizes) and bridging shown in Fig. 1c. Bridging occurs when particles smaller than the pore sizes in the filter medium form a cake; this occurs particularly when the particles are at a higher concentration in the feed. Several particles then attempt to pass simultaneously into a pore at the surface of the medium, but fail to do so and form a bridge over the pore entrance. This is essentially an arch stabilised by the flow environment around a pore entrance, and can become destabilised if flow velocities or directions are changed substantially.
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Wakeman at page 236, left col. 4. Particle size and the filtration mechanism; and right col. Fig. 1.
According to the filtration mechanism taught by Wakeman, one ordinary skill would be appraised that at least two different feed filtrates would be obtained when use a rotary pressure filter apparatus to filter a solid-liquid mixture:
(i). during the process of formation of a filter cake and or “Bridging” , some solids that have a size smaller than the pore of filter cloth would pass through the filter cloth with the liquid; which results in a filtrate having higher concentration of the small size solid product;
(ii). once the filter cake and/or “Bridging” is formed, most of the product solids including those having a smaller sizes would be captured by the filter cake and/or “Bridging”, which results in a filtrate having lower concentration of the small size solid and the main ingredients of the filtrate is catalyst and solvent .
F. Zaima, et al, US20100016629A1 (2010)( “Zaima”)
Zaima teaches that:
[0002] Generally, terephthalic acid is produced through liquid-phase oxidation reaction of a p-phenylene compound (e.g., p-xylene) in acetic acid serving as a solvent in the presence of a catalyst (e.g., cobalt or manganese), or in the presence of a catalyst together with a promoter (e.g., a bromine compound or acetaldehyde). A slurry containing crude terephthalic acid produced through such liquid-phase oxidation reaction is generally subjected to crystallization at ambient pressure and lowered temperature, followed by solid-liquid separation.
[0003] A mother liquor recovered through the solid-liquid separation contains catalyst-derived useful catalyst components such as heavy metal ions and bromide ions, and an industrial process requires recycling of these catalyst components for reduction of production cost. In the most convenient recycling method, the mother liquor is returned, as it is, to and reused in the reaction system. However, as has been known, since the mother liquor contains, for example, various organic impurities by-produced through liquid-phase oxidation reaction, and inorganic impurities derived from corrosion of an employed apparatus, when the mother liquor is reused as it is in the reaction system, the concentration of these impurities is gradually increased in the reaction system, and an increase in impurity concentration beyond a predetermined level adversely affects liquid-phase oxidation reaction. For example, in the case of production of terephthalic acid, the mother liquor is generally returned to the reaction system in a proportion of 70 to 98%, and the remaining portion (2 to 30%) of the mother liquor (i.e., a portion of the mother liquor which is not reused in the reaction system) is fed to a step of recovering acetic acid serving as a solvent. In view of the foregoing, various methods have been proposed for recovering catalyst components from the mother liquor fed to such an acetic acid recovery step, and reusing the catalyst components.
Zaima at page 1, [0002]-[0003], emphasis added.
Zaima clearly teaches one ordinary skilled artisan to recovery catalyst components from the mother liquor formed from solid-liquid separation of an oxidation reaction mixture for preparation of terephthalic acid.
Zaima teaches a method of recovering the catalyst from a mother liquor through a series of the following steps:
an adsorption step including regulating the ratio “amount by mole of bromide ions in the mother liquor/total amount by mole of heavy metal ions in the mother liquor” to 0.6 to 3, and then exposing the mother liquor to a pyridine-ring-containing chelate resin which has been heated to 35 to 140° C., so that the resin adsorbs catalyst-derived heavy metal ions and bromide ions, and also adsorbs a carboxylic acid mixture which has been by-produced through the liquid-phase oxidation reaction (hereinafter the carboxylic acid mixture will be referred to as a “by-produced carboxylic acid mixture”),
an elution step (A) of exposing hydrous acetic acid having a water content of 1 to 15 mass % to the pyridine-ring-containing chelate resin which has undergone the adsorption step, thereby yielding an eluate containing the by-produced carboxylic acid mixture,
an elution step (B) of exposing water or hydrous acetic acid having a water content of 20 mass % or more to the pyridine-ring-containing chelate resin which has undergone the elution step (A), thereby yielding an eluate containing catalyst-derived heavy metal ions and bromide ions, and
a displacement step of exposing hydrous acetic acid having a water content of 1 to 15 mass % to the pyridine-ring-containing chelate resin which has undergone the elution step (B), serving as a displacement liquid, thereby regenerating the resin.
Zaima at page 2, right col. [0026]-[0030], emphasis added. The Zaima method comprising:
(i). transferring a feed filtrate to a catalyst recovery zone;
(ii).recovering oxidation catalyst from the feed filtrate in the catalyst recovery zone to provide an effluent that is poor in catalyst.
While Zaima does not specify, however, one ordinary skilled artisan would be appraised that there is a step of “purging the effluent that is poor in catalyst” between step (2) and step (3) in the Zaima method, which meets the claim limitation of “purging a portion of the effluent that is poor in catalyst”.
Thus, Zaima teaches claim 1 limitation of:
transferring the feed filtrate to a catalyst recovery zone;
recovering oxidation catalyst from feed filtrate in the catalyst recovery zone to provide an effluent that is poor in catalyst; and
purging a portion of the effluent that is poor in catalyst
Claims 1, 3-19 are Obvious
It would have been prima facie obvious for one skilled artisan to arrive at the instantly claimed invention based on the teachings from Larsen, Zaima, Bartos and Wakeman with a reasonable expectation of success before the effective filing date of the claimed invention.
One ordinary skilled artisan seeking to significant throughput of terephthalic acid is motivated to modify the Bartos apparatus by including multiple filtering zones and use the modified apparatus as the solid-liquid separation device 190 in the Larsen method to filter the Larsen’s solid/liquid mixture. One ordinary skilled artisan is motivated to do so with a reasonable of success because:
(i). Bartos teaches that his rotary pressure filter apparatus having greater capacity and improved lifespan for the filter elements;
(ii). Bartos teaches that his rotary pressure filter apparatus can be used to filter a mixture of crude terephthalic acid product and a liquid containing acetic acid;
(iii). Bartos teaches that his rotary pressure filter apparatus can be modified by including multiple filtering zones; and
(iv) having multiple filtering zones in a rotary pressure filter apparatus can enhance filtration throughput of the apparatus.
As mentioned above that at least two different feed filtrates would be obtained at each of the filtration zones during using a rotary pressure filter apparatus to filter a solid-liquid mixture:
(i). a first filtrate containing high concentration of the product solid that have sizes smaller than the pore size of the filter cloth, which is collected before a filter cake (and or “Bridging”) is formed;
(ii). a second filtrate containing lower concentration of the product solid that have sizes smaller than the pore size of the filter cloth, which is collected after the filter cake (and or “Bridging”) is formed.
Given the first filtrates have higher concentration of the product solid, one ordinary skill is motivated to collected the first filtrates from different filtration zones and transfer at least a portion of the collections to the reactor zone as taught by Larsen.
Given the main ingredients of the second filtrates are catalyst and solvent, one ordinary skill is also motivated to further modify the proposed method by including a step of recovery of the catalyst in the second feed filtrates by transferring the second feed filtrates to a catalyst recovery zone with the method taught by Zaima. One ordinary skill is motivated to do so with a reasonable of success because Zaima teaches that through recovery of the catalyst can reduce of production cost.
Over all, the prior arts methods teach each and every limitation of claim 1, therefore, claim 1 is obvious.
Claim 3 is obvious because one ordinary skill is motivated to cycle at least a portion of the recovered catalyst to the reactor zone.
Claims 4-5 are obvious because one ordinary skill is motivated to adjust the amount of filtrates based on the comparative sizes of the solid particles and pores of filter cloth. "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. MPEP 2144.05.II. Herein, neither the prior art nor the application provides any evidence the claimed volume ratio is critical for the claimed method. On the contrary, the specification discloses that “In certain embodiments, the ratio of the volume of the first feed filtrate (collected in filter zone 364a) to the second feed filtrate (collected in filter zone 364b) is in the range of 1:20 to 3:1, or 1:10 to 3:1, or 1:5 to 3:1, or 1:20 to 2.5:1, or 1:20 to 2:1, or 1:10 to 2.5:1, or 1:5 to 2:1”.
Claim 6 is obvious because as mentioned above that once a filter cake is formed almost of the solids including those having a size smaller would be captured by the filter cake, resulting in the second filtrates contain less amount and the first filtrates contain predominant amount of the solid of the whole filtration. Regarding to the claimed concentration, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. MPEP 2144.05.II. Herein, neither the prior art nor the application provides any evidence the claimed precent amount is critical for the claimed method. Further, one ordinary skill has a motivation to adjust the pore size of the filter cloth to increase the filtration efficacy thus arrive at the claimed concentration.
Claim 7 is obvious because Larsen teaches that the solid/liquid mixture is transferred to the rotary pressure filter from a crystallization zone in which the aromatic carboxylic acid is crystallized.
Claims 8-9 are obvious because Bartos teaches filtering operation forms a filter cake, and washing the filter cake in a first wash zone with a wash fluid to form a first wash filtrate. See Bartos at page 7, [0028]. With regards to the claimed ratio of the volume of the wash filtrate to the first feed filtrate, "[W]here the general conditions of a claim are disclosed in the prior art, it is not inventive to discover the optimum or workable ranges by routine experimentation. MPEP 2144.05.II.
Claim 10 is obvious because one ordinary skill is also motivated to transfer some portion of the first wash filtrate to the reactor zone as recycle because the first wash filtrate containing product, catalyst and/or unreacted starting material.
Claim 11, 16 are obvious because one ordinary skill is motivated directly transferring at least portion of the first feed filtrate to the reactor zone as recycle given Larsen teaches to transfer some portion of the first feed filtrate to the reactor zone.
Claims 12-13 and 17 are obvious because Larsen teaches to transfer some portion of the feed filtrate to the reactor zone through drum 192 as indicated in Figure 1.
Claims 14-15 and 19 are obvious because:
(i). Larsen teaches that his method is used to manufacture of pure forms of terephthalic acid. See Larsen at page 6, paragraph 1, the last two line; which is emphasized by Larsen claim 12;
(ii). Larsen also teaches that the liquid feed material in Figure 1 comprise an aqueous acetic acid solution (e.g., containing about 70 to about 95 wt. % acetic acid). See Larsen at page 7, paragraph 1, line 1-3.
Therefore, one ordinary skill seeking pure terephthalic acid is motivated to utilize acetic acid as solvent to prepare pure terephthalic acid with the proposed method, therefore, claims 14-15 and 19 are obvious.
Applicant’s Argument
Applicant’s argument on Larsen & Zaima is not addressed separately given the rejection above is based on a combination of Larsen, Zaima and Bartos.
Applicant argues on the ground that neither Zaima nor Bartos teaches to collect two different filtrates from different zones of the rotary pressure filter apparatus. See Response to Zaima& Bartos at page 10-13 of the Remarks filed on 11/25/2025. These argument has been fully considered but not persuasive because:
(i). as mentioned in the rejection above that Bartos teaches that his rotary pressure filter apparatus can be modified by including multiple filtering zones, therefore, one ordinary skill is motivated to modify Bartos’s apparatus by including multiple filtering zones, use the modified apparatus as the solid-liquid separation device 190 in the Larsen method to filter the Larsen’s solid/liquid mixture and collect the filtrates produced in different filtrate zone;
(ii). according to the filtration mechanism taught by Wakeman, one ordinary skill would be appraised that at least two different feed filtrates would be obtained when use a rotary pressure filter apparatus to filter a solid-liquid mixture:
(1). at the first stage of the filtration during which a filter cake is not formed yet, some small size solid product would be forced pass through the filter cloth pore as the filtration is conducted under high pressure, therefore, the resulted filtrate contains higher concentration of small size solid product; and
(2) at the second stage of the filtration wherein the filter cake formed and compressed by the high pressure, solid product including small size solid product would be filtered by the compressed filter cake, therefore, the resulted filtrate contains catalyst, solvent, unreacted starting material.
Given the first filtrates have higher concentration of small size solid product, catalyst, solvent/unreacted starting material, one ordinary skill is motivated to recycle at least some portion of it to the reactor; given the main ingredients of the second filtrates are catalyst and solvent, one ordinary skill is motivated to recycle the catalyst from the second filtrates.
Thus, the methods taught by Larsen, Zaima and Bartos meets each and every limitation of the claimed invention, therefore, the claimed invention is obvious over the arts.
Conclusion
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/FRANK S. HOU/Examiner, Art Unit 1692
/ALEXANDER R PAGANO/Primary Examiner, Art Unit 1692