(12) INTERNATIONAL APPLICATION PUBLISHED UNDER THE PATENT COOPERATION TREATY (PCT)
`
`<19>Worw I|||||||||||||||||||||i||||||||||||i||||||IiIIIi||||||||||||||||||||||||i||||||||||||i|||||||||
`International Bureau
`in
`(10) International Publication Number
`
`WO 2010/111288 A2
`
`Agents: REED, Carl, T. et a1.; Workman Nydegger, 60
`East South Temple, 1000 Eagle Gate Tower, Salt Lake
`City, UT 84111 (US).
`
`Designated States (unless otherwise indicated, for every
`kind ofnational protection available): AE, AG, AL, AM,
`A0, AT, AU, AZ, BA, BB, BG, BH, BR, BW, BY, BZ,
`CA, CH, CL, CN, CO, CR, CU, CZ, DE, DK, DM, DO,
`DZ, EC, EE, EG, ES, FI, GB, GD, GE, GH, GM, GT,
`HN, HR, HU, ID, IL, IN, IS, JP, KE, KG, KM, KN, KP,
`KR, KZ, LA, LC, LK, LR, LS, LT, LU, LY, MA, MD,
`ME, MG, MK, MN, MW, MX, MY, MZ, NA, NG, NI,
`NO, NZ, OM, PE, PG, PH, PL, PT, RO, RS, RU, SC, SD,
`SE, SG, SK, SL, SM, ST, SV, SY, TH, TJ, TM, TN, TR,
`TT, TZ, UA, UG, US, UZ, VC, VN, ZA, ZM, ZW.
`
`Designated States (unless otherwise indicated, for every
`kind of regional protection available): ARIPO (BW, GH,
`GM, KE, LS, MW, MZ, NA, SD, SL, SZ, TZ, UG, ZM,
`ZW), Eurasian (AM, AZ, BY, KG, KZ, MD, RU, TJ,
`TM), E1n'opean (AT, BE, BG, CH, CY, CZ, DE, DK, EE,
`ES, FI, FR, GB, GR, HR, HU, IE, IS, IT, LT, LU, LV,
`MC, MK, MT, NL, NO, PL, PT, RO, SE, SI, SK, SM,
`TR), OAPI (BF, BJ, CF, CG, CI, CM, GA, GN, GQ, GW,
`ML, MR, NE, SN, TD, TG).
`
`[Continued on nextpage]
`
`(57) Abstract: Oxidation process can include:
`introducing small droplets of liquid reaction
`mixture having oxidizable reactant, catalyst,
`and solvent
`i11to a reaction zone containing
`oxygen and diluent gas; and oxidizing the reac-
`tant with the oxygen at a suitable reaction tem-
`perature and a suitable reaction pressure to
`produce an oxidized product. The liquid reac-
`tion mixture can have an aromatic feedstock
`
`having an oxidizable substituent as the oxidiz-
`able reactant. The oxidized product can include
`an aromatic compound having at least one car-
`boxylic acid. For example, the aromatic feed-
`stock can include a benzene ring having at
`least one oxidizable alkyl substituent, furan
`hetero-ring having at least one oxidizable alkyl
`substituent, a naphthalene poly-ring having at
`lcast onc oxidizable alkyl substituent, deriva-
`tives thereof, and mixtures thereof.
`
`(43) International Publication Date
`30 September 2010 (30.09.2010)
`
`International Patent Classification:
`
`C07C 51/255 (2006.01)
`C07C 63/00 (2006.01)
`B01J19/26 (2006.01)
`
`B01] 8/00 (2006.01)
`B01J 12/00 (2006.01)
`
`International Application Number:
`PCT/US2010/028343
`
`(74)
`
`(81)
`
`International Filing Date:
`
`Filing Language:
`
`Publication Language:
`
`23 March 2010 (23.03.2010)
`
`English
`
`English
`
`Priority Data:
`61/162,406
`
`23 March 2009 (23.03.2009)
`
`US
`
`Applicant for all designated States except US): UNI-
`VERSITY OF KANSAS [US/US]; 2385 Irving Hill
`Road, Lawrence, KS 66045-7563 (US).
`
`Inventors; and
`Inventors/Applicants (for US only): SUBRAMANIAM,
`Bala [US/US]; 1613 Troon Lane, Lawrence, KS 66047
`(US). BUSCH, Daryle, H. [US/US]; 1492 E. 902 Road,
`Lawrence, KS 66049 (US). NIU, Fenghui [US/US]; 3717
`Elizabeth Ct, Lawence, KS 66049 (US).
`
`(54) Title: SPRAY PROCESS FOR SELECTIVE OXIDATION
`
`N <o
`
`o
`0::
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`NV
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`-1
`V-1
`V-1E
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`Petitioners‘ Exhibit 1030, Page 1 of 32
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`aV
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`-1
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`cN g
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`Petitioners' Exhibit 1030, Page 1 of 32
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`Published:
`
`— without international Search report and to be republished
`upon receipt oftlzat report (Rule 48.2(g))
`
`Petitioners‘ Exhibit 1030, Page 2 of 32
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`Petitioners' Exhibit 1030, Page 2 of 32
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`

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`WO 2010/111288
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`PCT/US2010/028343
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`SPRAY PROCESS FOR SELECTIVE OXIDATION
`
`CROSS-REFERENCE
`
`This patent application claims the benefit of U.S. provisional application
`
`61/162,406, filed on March 23, 2009, entitled “Spray Process For Selective Oxidation,”
`
`which provisional application is incorporated herein by specific reference in its entirety.
`
`This invention was made with government support under EEC-0310689 awarded
`
`by the National Science Foundation. The government has certain rights in the invention.
`
`BACKGROUND OF THE INVENTION
`
`Oxidation processes are common in industrial processes for preparing various
`
`types of substances. Selectivity towards and purity of the desired product, inherent safety
`
`and minimization of waste & environmental emissions are constant challenges that
`
`industrial oxidation processes face. As such, improvements in oxidation processes and
`
`the reaction systems that conduct the oxidation are continually being sought.
`
`The catalytic liquid-phase oxidation ofpara-xylene to terephthalic acid (hereafter,
`
`TPA) with Co/Mn/Br based catalyst, known as the Mid-Century Process, was developed
`
`in the 1950s. In 1965, a hydrogenation step to purify TPA was added to help remove 4-
`
`carboxybenzaldehyde from the reaction product through conversion to water-soluble
`
`para-methylbenzyl alcohol and crystallization.
`
`Another related reaction scheme produces crude TPA at relatively mild oxidation
`
`conditions with a metals/bromide catalyst system. The production of isophthalic or TPA
`
`from the corresponding xylenes has also been proposed using acetaldehyde as a promoter
`
`for the reaction. Since this process does not use bromine as a catalyst promoter,
`
`less
`
`exotic reactor materials are suitable. Another known process is characterized by the
`
`simultaneous oxidation of para-xylene and methyl para-toluate at mild temperature and
`
`comparatively low pressure without acetic acid solvent.
`
`However, all of these processes share a common shortcoming - an inadequate or
`
`non-optimal 02 mass transfer rate in the liquid phase. The mass transfer is accomplished
`
`in a stirred liquid phase reactor, wherein the air is vigorously bubbled through the liquid
`
`phase. The crude TPA solid produced via this process is separated and further purified in
`
`a subsequent stage to reduce the 4—carboxybenzaldehyde content. Further, roughly 5% of
`
`the acetic acid entering the liquid phase reactor is also oxidized (e.g., burned) in this
`
`process. Therefore, there still remains a need in the art to have an improved process that
`
`-1-
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`Petitioners‘ Exhibit 1030, Page 3 of 32
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`provides increased 02 mass transfer rate for the production of TPA and other oxidation
`
`reactions similar to the ones discussed above.
`
`SUMMARY
`
`Generally, the present invention meets this and other needs through providing an
`
`oxidation system and process for selective oxidation through a spray process where each
`
`droplet can function as a micro-reactor for selective oxidation of a substrate. While the
`
`reaction proceeds within the liquid droplet, some reactions may occur in the vapor or gas
`
`phase, such that the majority of reaction occurs substantially in the liquid phase of the
`
`doplets.
`
`In one embodiment, an oxidation process can include: introducing small droplets
`
`of a liquid reaction mixture having an oxidizable reactant, a catalyst, and a solvent into a
`
`gaseous reaction zone containing oxygen and a diluent gas; and oxidizing the reactant
`
`with the oxygen at a suitable reaction temperature and a suitable reaction pressure to
`
`produce an oxidized product. The liquid reaction mixture can have an aromatic feedstock
`
`having an oxidizable substituent as the oxidizable reactant. The oxidized product can
`
`include an aromatic compound having at least one carboxylic acid. For example, the
`
`aromatic feedstock can include a benzene ring having at least one oxidizable alkyl
`
`substituent,
`
`furan hetero-ring having at
`
`least one oxidizable alkyl
`
`substituent, a
`
`naphthalene poly-ring having at least one oxidizable alkyl substituent, derivatives thereof,
`
`and mixtures thereof Examples of the aromatic feedstock include para-xylene, meta-
`
`xylene, ortho-xylene, pseua’0—cumene, 3-chloro-meta-xylene, 2,6-dimethylnaphthalene,
`
`1,5-dimethylnaphthalene, 2,7- dimethylnaphthalene, 5-hydroxymethylfurfural, furfural, 5-
`
`forinylfurfural, and mixtures thereof as well as similar compounds or derivatives thereof
`
`In one embodiment, the aromatic feedstock can include para-xylene (p-xylene)
`
`and the oxidized aromatic compound product having at least one carboxylic acid can
`
`include terephthalic acid.
`
`Alternatively,
`
`the aromatic feedstock can include 5-
`
`h_vdroxymethylfurfural and the oxidized product is an aromatic compound having at least
`
`one carboxylic acid includes furan-2,5-dicarboxylic acid.
`
`In one embodiment, the oxidized product precipitates from the droplets as a
`
`substantially pure solid material.
`
`In one embodiment,
`
`the aromatic feedstock includes a partially-oxidized
`
`derivative of at least one member selected from the group consisting of p-toluic acid
`
`(PTA), p-tolualdehyde (p-Ta), p-hydroxymethyl benzoic acid,
`
`terephthaldehyde, 4-
`
`-2-
`
`Petitioners‘ Exhibit 1030, Page 4 of 32
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`

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`carboxybenzaldehyde
`
`(4-CBA), p-methylbenzyl
`
`alcohol,
`
`5-hydroxymethylfuran-2-
`
`carboxylic acid, 2,5-diformylfuran, furfural-5-carboxylic acid, and mixtures thereof.
`
`In one embodiment,
`
`the catalyst can include solvent-soluble compositions of
`
`palladium, platinum, cobalt, manganese, vanadium,
`
`titanium,
`
`tin, antimony, bismuth,
`
`molybdenum, and mixtures thereof.
`
`In one embodiment, the catalyst can further include a co-catalyst dissolved in the
`
`liquid reaction mixture. For example, the co-catalyst can include manganese, bromine, or
`
`hydrogen bromide.
`
`In one embodiment, the solvent includes acetic acid. Optionally, the acetic acid
`
`contains about 0.1 to 10 % water by weight or volume.
`
`In one embodiment, the diluent gas is inert. For example, the diluents gas can
`
`include nitrogen, carbon dioxide or a noble gas.
`
`In one embodiment, an oxidation intermediate of the oxidizable reactant is added
`
`to the liquid reaction mixture. For example, the oxidation intermediate is selected from
`
`the group consisting of p—toluic acid, p—tolualdehyde, p—hydroxymethyl benzoic acid,
`
`terephthaldehyde, 4-carboxybenzaldehyde, p-methylbenzyl alcohol, derivatives thereof,
`
`and mixtures thereof.
`
`In one embodiment,
`
`the liquid reaction mixture in the small droplet form is
`
`contacted with the oxygen at from about 100 to about 300 °C. Also, the process can
`
`include preheating the liquid reaction mixture or the gaseous reaction zone to 100-300 °C
`
`prior to the liquid reaction mixture being sprayed into contact with the oxygen-containing
`
`gas.
`
`In one embodiment, the liquid reaction mixture droplet is contacted with the
`
`oxygen for a time period of about 0.1 second to about 60 minutes.
`
`In one embodiment, the reaction pressure is in a range of about 1 to about 100
`
`atmospheres.
`
`In one embodiment, the reaction pressure is chosen such that the reaction mixture,
`
`dominated by the solvent, begins to boil if the droplet temperature rises (due to heat
`
`evolved by the reaction) and attains a certain temperature. However, when the reaction
`
`mixture begins to boil, the latent heat of evaporation is removed from the droplet causing
`
`it to cool. In this manner, the droplet temperature can be self-controlling and stable.
`
`In one embodiment, the process can include spraying the reaction mixture through
`
`a nozzle to form the fine mist spray in the reaction zone containing the gaseous oxidant.
`
`The nozzle can be a single fluid-type nozzle that sprays a fine mist into an oxygen-
`
`-3-
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`containing gas. Optionally, a gas, with or without oxygen, can be combined with the
`
`reaction mixture and sprayed through the nozzle with the reaction mixture.
`
`In one embodiment, oxidation or combustion of the solvent or other oxidizable
`
`components (e. g., not oxidizable reactant) to CO or CO2 is avoided or decreased. This
`
`can be obtained by minimizing the temperature gradients in the reactor, the pressure and
`
`by minimizing the residence time of the droplets in the reactor.
`
`In this manner,
`
`combustion of the solvent or other oxidizable components to form CO or CO2 is
`
`substantially decreased.
`
`In one embodiment, the small droplets are from 0.1 micron to about 1 mm in
`
`average diameter. Also, the small droplets can be a fine mist of droplets.
`
`In one embodiment, an oxidation reaction system can include: a liquid reaction
`
`mixture having an oxidizable reactant, a catalyst, and a solvent, an oxidizing gas having
`
`oxygen and a diluent gas, a reaction vessel configured for retaining the oxidizing gas in a
`
`gaseous reaction zone, and a sprayer system having a nozzle configured for spraying
`
`small droplets of the liquid reaction mixture into the reaction zone.
`
`The various components of the liquid reaction mixture can be individually
`
`supplied to the sprayer system for combination into the liquid reaction mixture and being
`
`sprayed into the reactor, or can be supplied (and optionally stored) premixed or partly
`
`premixed and partly as individual components.
`
`In like fashion, the oxidizing gas can be
`
`supplied to the reaction zone as a premix of one or more oxygen-containing gases with
`
`one or more diluent gases, or as separate oxygen-containing gas and diluent gas flows, or
`
`as individually-introduced, discrete gases.
`
`In one embodiment,
`
`the reaction vessel can include a collection member
`
`configured for collecting an oxidized product that precipitates as a solid from the reaction
`
`zone or from the liquid droplets.
`
`In one embodiment, the reaction vessel can include a temperature control system
`
`configured for obtaining a reaction temperature being at from about 100 to about 300 °C.
`
`For example, the temperature control system can be configured to maintain a substantially
`
`uniform temperature throughout the reaction vessel.
`
`In one embodiment, the reaction vessel can include a pressure control system
`
`configured to maintain pressure in the reaction vessel at from about I to about 100
`
`atmospheres.
`
`-4-
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`DESCRIPTION OF THE FIGURES
`
`Figure 1
`
`is a schematic diagram of an embodiment of an oxidation reaction
`
`system.
`
`Figure 2A is a graph of a temperature profile obtained with an oxidation reaction
`
`system having substantially uniform temperature across a cross-sectional profile of the
`
`reaction vessel.
`
`Figure 2B is a graph of a temperature profile obtained with an oxidation reaction
`
`system having non-uniform temperature or a high temperature gradient across a cross-
`
`sectional profile of the reaction vessel.
`
`DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS
`
`Generally, the present invention is related to a system and method that employs a
`
`novel spray process for selective oxidation reactions, such as those that are catalyzed
`
`homogeneously. The spray process is configured to produce a high number of small
`
`droplets, where the droplets function as micro-reactors and the reaction substantially
`
`occurs within the droplets. However,
`
`it may be possible for some of the oxidation
`
`reaction to occur in the vapor or gas phase outside of the droplet. Also, in embodiments
`
`where the solvent is included at the base of the reactor as a bulk liquid, some oxidation
`
`may occur in the bulk liquid solvent. That is, the oxidation reaction occurs substantially
`
`within the small droplets in which the temperature rise due to heat of reaction may be
`
`controlled by evaporative cooling. The temperature can be controlled within a pressure
`
`range so that the yield losses to undesired byproducts can be minimized. For example,
`
`the system and method can be used in a novel spray process for selective oxidations
`
`including p-xylene oxidation to produce terephthalic acid as well as related oxidation
`
`reactions. Additionally, other reactants can be used in the oxidation process in order to
`
`produce desired products. Moreover, the system and process may be useful in other
`
`reactions other than oxidation reactions.
`
`In addition to oxidation, the reactions that can be performed with the system and
`
`methods described herein can include liquid phase ozonolysis, hydrogenation reactions,
`
`carbonylation reactions, and syngas reactions. Such reaction types are known and one
`
`skilled in the art can select reagents that can be prepared into a reaction mixture that can
`
`be sprayed into a mist of small droplets for the reaction medium. These reactions can
`
`have significant improvements in yield and purity when gas-liquid mass transfer is a rate-
`
`limiting step. Syngas is a gas mixture of carbon monoxide and hydrogen, which can be
`
`produced from coal through pyrolysis to coke, followed by an exothermic reaction that
`
`-5-
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`forms carbon monoxide and then produces hydrogen from reacting carbon monoxide with
`
`water vapor.
`
`For ozonolysis, the substrate can be an alkene or alkyne with ozone cleaving the
`
`substrate to produce a alcohols, aldehydes, ketones, or carboxylic acids. Hydrogenation
`
`can include substrates that have unsaturated alkyl groups that are hydrogenated by adding
`
`a pair of hydrogens in place of a double bond. Carbonylation includes reactions that
`
`introduce a carbon doubled bonded to oxygen from carbon monoxide into an organic or
`
`inorganic substrate (e.g., hydroformylation and Reppe chemistry).
`
`Accordingly, a novel system and process is disclosed herein that can be used to
`
`perform homogeneous catalytic O2 oxidations.
`
`The novel system and process can
`
`overcome O2 availability limitations in the liquid phase that have limited the effectiveness
`
`and yield of prior processes, such as the Mid-Century proces.
`
`The O2 availability
`
`limitation has been overcome by configuring the system to spray the liquid phase
`
`(containing the substrate and catalyst dissolved in a solvent) as small droplets that each
`
`serve as rnicro—reactors, and where each droplet has a small enough size that allows for
`
`sufficient oxygen permeation throughout the droplet. The novel system and process can
`
`be used to oxidize various types of oxidizable substrates. The oxidizable substrates can
`
`include oxidizable moieties that can by oxidized by oxygen.
`
`One skilled in the art will appreciate that the inventive system and process can be
`
`used beyond the context of oxidation of a liquid substrate. As such, the system and
`
`process can be used for any liquid phase (e. g., in a small droplet) homogeneous catalytic
`
`reactions invoving a gaseous reactant (e.g., oxygen) wherein the gas-liquid mass transfer
`
`is rate-limiting. The small size of the droplets significantly improves the gas-liquid mass
`
`transfer rate and thereby improves the available molecular oxygen for oxidation.
`
`Accordingly,
`
`the system and process using small droplet reactors can improve the
`
`availability of gaseous O2, and thereby improve the reaction process compared to bulk
`
`liquid oxidation or large liquid volume oxidation.
`
`Improvements are also obtained from
`
`faster reaction times and tighter temperature control. The advantages of the novel system
`
`and process include high throughput,
`
`less waste, higher product purity, and improved
`
`safety as well as others.
`
`The system and process are operated in a manner to avoid combustion of the
`
`solvent for the oxidizable reactant. The system can be controlled within a pressure range
`
`to have a selected temperature range of operation that reduces the likelihood of solvent
`
`being burned. Further, the system can be operated with the solvent for the oxidizable
`
`-6-
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`reactant being in equilibrium with its vapor at the reactor pressure and temperature.
`
`In
`
`this manner, the solvent in the droplets remains substantially as a saturated liquid in the
`
`reactor with little if any evaporation.
`
`If the solvent in the liquid droplets evaporates
`
`substantially, the homogeneous catalyst may precipitate, which reduces the effectiveness
`
`of the system and process. To maintain the solvent as a saturated liquid, the spray
`
`solution must be preheated to the reactor temperature prior to spraying. Further, the
`
`reactor pressure is maintained such that the temperature of the droplets do not exceed the
`
`boiling point of the solvent at that pressure.
`
`The system and process can include spraying a liquid solvent containing
`
`dissolved oxidizable reactant and catalyst as fine droplets (e. g., as a mist) into a chamber
`
`containing 02 in an inert background gas. The droplets can be formed as small as
`
`possible from a spray nozzle, such as a nebulizer, mister, or the like. The smaller droplets
`
`containing the reactant result in an increased interfacial surface area of contact between
`
`the liquid droplets and gaseous 02. The increased interfacial surface area can lead to
`
`improved reaction rates and product quality (e. g., yield and purity). Also, the droplets are
`
`sufficiently small such that the O2 penetrates the entire volume of the droplets by
`
`diffusion and is available at stoichiometric amounts throughout the droplet for the
`
`selective oxidation to proceed to the desired product.
`
`In one embodiment, the system and process can be used to oxidize an oxidizable
`
`reactant without the use of a catalyst. Accordingly, non-catalytic oxidation processes
`
`using gaseous 02 as an oxidant can be performed in the system described herein.
`
`In another embodiment, the system and method increase the interfacial mass
`
`transfer area between the liquid phase and 02 by spraying the reaction mixture as fine
`
`droplets into a gas having an excess of molecular oxygen.
`
`In contrast to previous
`
`oxidation systems and methods, the present invention provides the liquid phase as the
`
`dispersed phase and the gas phase as the continuous phase. Previous oxidation systems
`
`utilized liquid as the continuous phase with gas being the dispersed phase that is bubbled
`
`through the liquid. Accordingly, the novel system and method operate in an opposite
`
`manner from the previous systems and methods (eg., Mid-Century process).
`
`In other
`
`terms, the system and method of the invention can include an oxygen gas phase as a fixed
`
`phase or batch phase. Correspondingly, the liquid droplets that are sprayed into the
`
`oxygen-containing gas environment (e. g., gaseous reaction zone) are dispersed or added
`
`continuously in the form of a spray or mist.
`
`-7-
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`Petitioners‘ Exhibit 1030, Page 9 of 32
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`The small reactant droplets or mist can provide an environment (e. g., droplet) for
`
`oxidation to occur that is several hundred microns or less in diameter. If the surrounding
`
`molecular oxygen is able to instantly penetrate the droplet (i.e., if the O2 diffusion time
`
`scale (Rp2[D5) is shorter than the kinetic time scale), then the oxidation can progress
`
`substantially uniformly throughout the droplet. The nearly uniform oxidation can allow
`
`the product to develop at high purity. For example, the high conversion rate of p-xylene
`
`to TPA allows the TPA product to form and precipitate out of the droplet at relatively
`
`high purity. Note that De is the diffusivity of O2 in the solvent reaction mixture and R1, is
`
`the radius of the droplet.
`
`In contrast, if the droplet size is “large”, the oxygen diffusion
`
`time scale (R132/De) would be much longer than the kinetic time scale.
`
`In this latter
`
`suboptimal scenario, the TPA formation and precipitation commence from the outer shell
`
`of the droplet, progressing toward the inner core of the droplet. Once the solid forms near
`
`the outer layer of the droplet, the O2 diffusion to the inner core can be hindered, and
`
`incomplete oxidation can result leading to a less pure TPA product, contaminated by
`
`intermediates. Thus, smaller droplets favor the production of purer product.
`
`In order to control the reaction as described herein, the size of the droplets can be
`
`controlled. The droplets can be formed as a fine mist of individual small droplets (e.g.,
`
`about 10 microns to about 100 microns), as fine droplets (e. g., about 100 microns to about
`
`300 microns), to light droplets (e.g., about 300 microns to about 1,000 microns), as well
`
`as larger droplets. However, smaller droplets are preferred as described herein. A “mist”
`
`is considered to be a plurality of small droplets or droplets of a size commensurate with
`
`this invention, and can be formed with an atomizing nozzle.
`
`The system and process described herein can reduce the amount of solvent (e. g.,
`
`acetic acid) that is combusted/oxidized in the reaction, and therefore reduce side-products
`
`that are formed as a consequence of the burning of acetic acid. Although the surface area
`
`between acetic acid and O2 is increased, the burning is not mass transfer controlled but
`
`depends on the contact time between the acetic acid and oxygen.
`
`This contact time is
`
`significantly reduced in the spray process compared to the conventional process (i.e.,
`
`Mid-Century process) as the acetic acid can also be continuously removed during the
`
`spray process with minimal holdup in the reactor.
`
`The exothermic oxidation reactions can lead to the temperature rise of reaction
`
`mixture, and thereby lead to solvent burning if the conditions of the macroscopic reactor
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`are not properly controlled. The adiabatic temperature increase (ATM) in the reaction
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`mixture for total combustion of the oxidizable reactant (e. g., p-xylene) can be estimated
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`-3-
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`Petitioners' Exhibit 1030, Page 10 of 32
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`following standard calculation procedures.
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`It was found that the ATM values increases
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`with pressure and the maximum temperature attained represents the boiling point of the
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`solvent (e.g., acetic acid) at that pressure. The latent heat of vaporization provides enough
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`heat capacity to absorb the heat of reaction and maintain the temperature at the phase
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`change temperature (e.g., boiling temperature) without causing the reaction mixture to
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`completely evaporate. As such,
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`the operating pressure can be selected to limit the
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`adiabatic temperature increase and prevent the temperature from increasing to or above a
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`level where solvent burning is minimized. Higher operating pressure can lead to higher
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`boiling points for the solvent, which in turn can cause the solvent to burn and produce
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`side products. It was also found through calculations that the maximum local temperature
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`of every single droplet in which reaction occurs again reaches the solvent boiling point at
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`the given pressure.
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`In the commercial Mid-Century process, the 02 mass transfer rate in the liquid
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`phase is accomplished in a stirred liquid phase reactor, wherein the air is vigorously
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`bubbled through the liquid phase. The crude TPA solid produced via this process is
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`separated and further purified in a subsequent stage to reduce the 4-carboxybenzaldehyde
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`content (the intermediate oxidation product which is the main impurity). Further, roughly
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`5% of the acetic acid entering the reactor is also oxidized (burned) in this process. Since
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`the purity of the solid TPA product and effectiveness of the oxidation reaction can depend
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`on the interfacial area, and thereby, droplet size, smaller droplets of reactant suspended in
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`the gas having 02 can significantly improve the oxidative reaction and product yield and
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`purity. For example, smaller droplets lead to purer TPA products and higher TPA yields.
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`Figure 1 shows a diagram of an embodiment of an oxidation system 100 that can
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`be used in the spray oxidation processes described herein. The oxidation system 100, as
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`shown in Figure 1, is configured for p-xylene oxidation to TPA; however, the system 100
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`can be used for any oxidation as described herein.
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`The system 100 can include a reaction mixture reservoir 102, an oxygen reservoir
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`104, and a diluent gas reservoir 106 in fluid communication with a reactor 108, such as
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`through fluid pathways 110. Fluid pathways 110 are shows by the tubes that connect the
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`various components together, such as for example, reaction mixture reservoir 102 is
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`fluidly coupled to a pump 114, splitter 118, heater and junction 116 before being passed
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`through the nozzle 128. Optionally, a second gas reservoir 107 having an oxygen or
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`diluents gas can be included that can be in fluid communication with the reactor 108. The
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`fluid pathways 110 can include one or more valves 112, pumps 114, junctions 116, and
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`-9-
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`Petitioners' Exhibit 1030, Page 11 of 32
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`splitters 118 to allow fluid flow through the fluid pathways 110. Accordingly,
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`the
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`arrangement can be configured to provide for selectively transferring a reaction mixture,
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`oxygen gas, oxygen-containing gas, inert gas, and one or more diluent gases to the reactor
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`108 so that an oxidation reaction can be performed as described.
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`Additionally, the oxidation system 100 can include a computing system 120 that
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`can be operably coupled with any of the components of the oxidation system 100.
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`Accordingly, each component, such as the valves 112 and/or pumps 114 can receive
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`instructions from the computing system 120 with regard to fluid flow through the fluid
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`pathways 110. General communication between the computing system 120 and oxidation
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`system components 100 is represented by the dashed-line box around the oxidation
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`system 100. The computing system 120 can be any type of computing system ranging
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`from personal-type computers to industrial
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`scale computing systems.
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`Also,
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`the
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`computing system can include a storage medium, such as a disk drive, that can store
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`computer-executable instructions (e. g., software) for performing the oxidation reactions
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`and controlling the oxidation system 100 components.
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`The fluid pathway 110 that fluidly couples the reaction mixture reservoir 102
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`may include a heater 122 as shown. The heater 122 can pre-heat the reaction mixture to a
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`desired temperature before being introduced into the reactor 108. While not shown, the
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`fluid pathway 110 that fluidly couples any of the gas reservoirs can similarly include a
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`heater to heat the gases to a temperature before being introduced into the reactor 108.
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`Any of the heaters 122 can be operably coupled with the computing system 120 so that
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`the computing system 120 can provide operation instructions to the heater 122, and/or the
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`heater 122 can provide operation data back to the computing system 120. Thus, the
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`heaters
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`122,
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`as well
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`as
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`any of the
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`components,
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`can be outfitted with data
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`transmitters/receivers (not shown) as well as control modules (not shown).
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`The fluid pathways 110 can be fluidly coupled with one or more nozzles 128
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`that are configured to spray the reaction mixture (and optionally including the oxygen-
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`containing and diluent gases from 104 and 106 and/or the gases from reservoir 107, if
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`nozzles 128 are employed for injecting both gases and liquids or a mixture of gases and
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`liquids) into the reactor 108.
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`The nozzles 128 in any such arrangements can be
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`configured to provide liquid droplets of the reaction mixture at an appropriately small size
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`that allows for the oxidation reaction to occur with limited evaporation of the solvent.
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`The nozzles 128 can spray the reaction mixture into a plurality of droplets within a size
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`range that is desired. While Figure 1 shows the nozzle 128 to be pointed downward, the
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`-10-
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`nozzle 128 in fact can be in any orientation and a plurality of nozzles 128 can be
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`configured into any arrangement.
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`Similarly,
`
`the droplets may be formed by other
`
`methods such as ultrasound to break up a jet of the spray solution.
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`The reactor 108 can include a tray 130 that is configured to receive the
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`oxidation product. As the oxidation product is formed, it can fall out of the droplets, such
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`as by precipitation, and land on the tray 130. Also, the tray 130 can be a mesh, filter, and
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`membrane or have holes that allow liquid to pass through and retain the oxidation
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`product. Any type of tray 130 that can catch the oxidation product can be included in the
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`reactor 108.
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`The reactor 108 can be outfitted with a temperature controller 124 that
`
`is
`
`operably coupled with the computing system 120 and can receive temperature
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`instructions therefrom in order to change the temperature of the reactor 108. As such, the
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`temperature controller 124 can