EP3250542A1 - Processes for producing acetic acid - Google Patents

Processes for producing acetic acid

Info

Publication number
EP3250542A1
EP3250542A1 EP15781530.9A EP15781530A EP3250542A1 EP 3250542 A1 EP3250542 A1 EP 3250542A1 EP 15781530 A EP15781530 A EP 15781530A EP 3250542 A1 EP3250542 A1 EP 3250542A1
Authority
EP
European Patent Office
Prior art keywords
acetic acid
concentration
reaction medium
resin
column
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Pending
Application number
EP15781530.9A
Other languages
German (de)
English (en)
French (fr)
Inventor
Sarah Lane ABREGO
Yaw-Haw LIU
Mark O. Scates
Ronald David Shaver
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Celanese International Corp
Original Assignee
Celanese International Corp
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Priority claimed from US14/694,913 external-priority patent/US9540302B2/en
Application filed by Celanese International Corp filed Critical Celanese International Corp
Publication of EP3250542A1 publication Critical patent/EP3250542A1/en
Pending legal-status Critical Current

Links

Classifications

    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/10—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction with carbon monoxide
    • C07C51/12—Preparation of carboxylic acids or their salts, halides or anhydrides by reaction with carbon monoxide on an oxygen-containing group in organic compounds, e.g. alcohols
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J39/00—Cation exchange; Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • B01J39/08—Use of material as cation exchangers; Treatment of material for improving the cation exchange properties
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/43—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation
    • C07C51/44—Separation; Purification; Stabilisation; Use of additives by change of the physical state, e.g. crystallisation by distillation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/47—Separation; Purification; Stabilisation; Use of additives by solid-liquid treatment; by chemisorption
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C51/00—Preparation of carboxylic acids or their salts, halides or anhydrides
    • C07C51/42—Separation; Purification; Stabilisation; Use of additives
    • C07C51/50—Use of additives, e.g. for stabilisation
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07C—ACYCLIC OR CARBOCYCLIC COMPOUNDS
    • C07C53/00—Saturated compounds having only one carboxyl group bound to an acyclic carbon atom or hydrogen
    • C07C53/08—Acetic acid
    • B—PERFORMING OPERATIONS; TRANSPORTING
    • B01—PHYSICAL OR CHEMICAL PROCESSES OR APPARATUS IN GENERAL
    • B01J—CHEMICAL OR PHYSICAL PROCESSES, e.g. CATALYSIS OR COLLOID CHEMISTRY; THEIR RELEVANT APPARATUS
    • B01J2208/00—Processes carried out in the presence of solid particles; Reactors therefor
    • B01J2208/00796—Details of the reactor or of the particulate material
    • B01J2208/00946—Features relating to the reactants or products
    • B01J2208/00955—Sampling of the particulate material, the reactants or the products

Definitions

  • Acetic acid production by carbonylation includes continuously reacting methanol and carbon monoxide in the presence of a catalyst in a reactor.
  • the reaction mixture present in the reactor comprises a transition metal, which may be a Group 9 metal, which may be iridium and/or rhodium, and may further include one or more solvents, water, various stabilizers, co- catalysts, promoters, and the like.
  • Reaction mixtures known in the art may comprise acetic acid, methyl acetate, methyl iodide, hydrogen iodide, a hydrogen iodide promoter, and the like.
  • a complex network of interdependent equilibria involving liquid acetic acid reaction components exists in the reactor, which include those directed to the formation of acetic acid, as well as those directed to the formation of various impurities which are also produced in the reactor.
  • Impurities which may be present in acetic acid include permanganate reducing compounds (PRCs) such as acetaldehyde.
  • PRCs permanganate reducing compounds
  • acetic acid processes disclosed in the art may further include various purification processes and control schemes wherein impurity formation is minimized and/or impurities produced are removed from the process or converted into product acetic acid.
  • a process comprises carbonylating at least one member selected from the group consisting of methanol, dimethyl ether, and methyl acetate in the presence of 0.1 to less than 14 wt. water, a rhodium catalyst, methyl iodide and lithium iodide, to form a reaction medium comprising acetic acid in a reactor; separating the reaction medium into a liquid recycle stream and a vapor product stream; separating the vapor product stream in up to 2 distillation columns in a primary purification train to produce a crude acid product comprising acetic acid comprising lithium cations; contacting the crude acetic acid product with a first purification resin comprising a cationic exchanger in the acid form within a first treatment device to produce an intermediate acid product; and contacting the intermediate acetic acid product with a second purification resin comprising a metal-exchanged ion exchange resin having acid cation exchange sites within a second treatment device to produce a purified
  • FIG. 1 is a schematic diagram of a process to produce acetic acid according to an embodiment
  • FIG. 2 is a schematic diagram of a series of treatment devices according to an embodiment
  • FIG. 3 is a cross-sectional view of a treatment device according to an embodiment.
  • FIG. 4 is a cross-sectional view of a sampling device according to an embodiment.
  • FIG. 5 is a block diagram showing the step for charging a treatment device column with resin according to embodiments. DETAILED DESCRIPTION
  • a mixture comprising acetic acid and/or methyl acetate may comprise acetic acid alone, methyl acetate alone, or both acetic acid and methyl acetate.
  • the percentage of exchanged active sites of the resin is based on the total exchange capacity in milliequivalents per gram (meq/g).
  • a cationic ion exchange resin having a cation exchange capacity of 2 meq/g, substitution of 2 meq/g with a silver ion constitutes 100% of the active sites being substituted with silver, 1 meq/g substitution constitutes 50% of the active sites being substituted.
  • acetic acid may be abbreviated as "AcOH";
  • methyl acetate may be abbreviated "MeAc”;
  • methyl iodide may be abbreviated as "Mel”;
  • CO carbon monoxide
  • Permanganate reducing compounds refers to oxidizable compounds which cause a fail designation of the permanganate test as is readily understood by one of skill in the art (cf. "A New System For Automatic Measurement of Permanganate Time," Laboratory Automation and Information Management, 34, 1999, 57-67).
  • Examples of permanganate reducing compounds (PRCs) include acetaldehyde, acetone, methyl ethyl ketone, butyraldehyde, crotonaldehyde, 2- ethyl crotonaldehyde, 2-ethyl butyraldehyde, and the like, and the aldol condensation products thereof.
  • an "overhead" of a distillation column refers to the lowest boiling condensable fraction which exits at the top, or proximate to the top, of the distillation column.
  • the residuum of a distillation column refers to the highest boiling fraction which exits at or near the bottom of the distillation column. It is to be understood that a residuum may be taken from just above the very bottom exit of a distillation column, for example, wherein the very bottom of the column is an unusable tar, a solid waste product, or a de minimis stream as would be readily understood by one of minimal skill in the art.
  • the overhead stream may be taken just below the upper most exit of a distillation column, for example, wherein the lowest boiling fraction is a non-condensable stream or represents a de minimis stream, as would be readily understood by one of minimal skill in the art.
  • an average residence time of a column feed stream within a column refers to the total flow rate provided to a column divided by the total unoccupied volume present in the column, unless otherwise stated.
  • treatment vessels which may be referred to as columns, have an inlet and an outlet.
  • the inside of the column also referred to herein as an inner chamber, is suitable for filling with purification resin.
  • treatment device and column are used interchangeably herein, unless otherwise indicated.
  • a treatment device and a column other than a distillation column are used interchangeably.
  • mass flow rate refers to kg/hr unless otherwise stated, and may be determined directly or calculated from volumetric measurements.
  • a total mass flow rate or a concentration of a component is qualified as being present, "if any", it is to be understood that the component may or may NOT be present in the stream above a detection limit of an appropriate analytical method as readily understood by one of minimal skill in the art.
  • a mass flow rate of a stream is "controlled" at either a specific flow rate or at a rate which is proportional to a mass flow rate of another stream, it is to be understood that such control includes varying the particular process flow stream directly, or controlling the mass flow of the particular stream by varying streams which directly affect the mass flow rate of the target stream, as readily understood by one of skill in the art. All such ratios are expressed as mass to mass weight percentages unless otherwise stated.
  • a carbonylatable reactant is any material which reacts with carbon monoxide under reaction conditions to produce acetic acid, or the intended product.
  • Carbonylatable reactants include methanol, methyl acetate, dimethyl ether, methyl formate, and the like.
  • a low water carbonylation process is defined as having a finite concentration of water in the carbonylation reactor of less than or equal to about 14 weight percent.
  • portion refers to a portion of the entire mass flow of the stream.
  • the stream may be combined with other streams (i.e., indirectly recycled), yet all of the components originally present in the stream are present after being combined.
  • a stream “derived” from another stream may include the entire stream or may include less than all of the individual components initially present in the stream.
  • a stream "derived" from a particular stream may thus include a stream which is subject to further processing or purification prior to disposition. For example, a stream which is distilled prior to being recycled is derived from the original stream.
  • limitations based on a comparison between an effect observed in the presence of a component relative to the effect observed in the absence of the same component refer to comparisons made under essentially identical conditions except the presence or absence of the identified component (e.g., essentially the same composition, essentially the same temperature, time, and other conditions).
  • Impurities present in acetic acid include various iodine containing species. Examples include alkyl iodides having from 1 to about 20 carbon atoms. The higher molecular weight alkyl iodides having more than about 6 carbons may be present at parts per billion levels in the final product. These impurities are problematic to various end uses of acetic acid and require removal according to various purity standards. Other impurities include various aldehydes and corrosion metals. These contaminants may be removed by contact of the acetic acid with a suitable purification resin at temperatures greater than about 50°C (cf. US6657078). The use of such purification resins, however, requires monitoring of both the final product and the resin itself to prevent impurities from "breaking through" the purification resin bed during production.
  • samples of the final product are readily obtainable, samples of the purification resin being employed in such purification processes are nearly impossible to obtain while the purification system is in operation. Furthermore, shutdown of such purification systems to obtain resin samples is uneconomical and often dubious.
  • a sampling device allows for both a liquid sample and a sample of the solid purification resin to be acquired and analyzed at various points along a resin bed. The ability to obtain these samples allows for improved monitoring and control over the process. These sample ports further allow for predicting when a resin will become exhausted prior to excessive amounts of impurities being present in the final product.
  • a method comprises providing a column comprising an inner chamber comprising an active purification resin located between a column inlet and a column outlet, the column further comprising one or more sample ports arranged between the column inlet and the column outlet, at least one sample port comprising a liquid sample port, a solid sample port, or both; and flowing an acetic acid stream having a first concentration of an impurity through the column at a temperature and flow rate sufficient to produce a purified acetic acid stream at the column outlet having a second concentration of the impurity, if any, which is less than the first concentration. Accordingly, the acetic acid contacts the purification resin within the column to remove impurities and purify the acetic acid.
  • the method further comprises opening at least one sample port prior to, or simultaneously with flowing the acetic acid stream through the column.
  • the impurity comprises iodine, chromium, nickel, iron, or a combination thereof.
  • the iodide may be an alkyl iodide.
  • the purification resin comprises a macroreticular, strong acid, ion exchange resin having at least about 1 percent active sites in a silver or mercury form, and/or the temperature is at least about 50°C.
  • the opening of at least one sample port may comprise obtaining a sample of the purification resin through at least one solid sample port, a liquid sample of the acetic acid stream present in the column through at least one liquid sample port, or a combination thereof, and the method further comprises determining a
  • the concentration of one or more of the impurities is
  • the impurity concentration of one or more of the samples is compared to a previously determined impurity concentration value, and a
  • the method may further comprise stopping the flow of acetic acid through the column.
  • the flow of acetic acid is stopped prior to exhaustion of essentially all of the active purification resin present in the column such that the impurity concentration in the product acetic acid does not render the acetic acid unsuitable for a particular end use.
  • a second column similar to the first column may be provided and the acetic acid flowed through and thus purified in the second column while flow through the first column has been stopped.
  • regeneration of the exhausted resin comprises removing at least a portion of the exhausted resin from the column and refilling at least a portion of the column with active purification resin.
  • at least a portion of the active resin used to refill the column comprises previously exhausted resin which has been regenerated into active purification resin.
  • at least a portion of the exhausted resin is regenerated into the active purification resin within the column.
  • a method comprises the steps of: (a) providing a column comprising an inner chamber bound by a plurality of sides radially arranged about a central axis and having an inlet end in fluid communication with, and longitudinally separated from, an outlet end through the inner chamber; (b) directing an amount of purification resin into the inner chamber sufficient to fill a portion of the inner chamber; (c) flowing an aqueous wash fluid from the outlet end through the inner chamber to the inlet end at a flow rate and for a period of time sufficient to wash and/or remove fines from the purification resin; and (d) flowing an acetic acid stream having a first concentration of an impurity through the column at a temperature and flow rate sufficient to produce a purified acetic acid stream at the column outlet having a second concentration of the impurity, if any, which is less than the first concentration.
  • the column comprises the one or more sample ports arranged between the column inlet and the column outlet, at least one sample port comprising a liquid sample port, a solid sample port, or both, and the method further comprises opening at least one sample port.
  • the aqueous wash fluid is flowed for at least 60 minutes.
  • step (c) of flowing an aqueous wash fluid through the column an amount of inert gas is directed into the column inlet to remove a portion of the wash fluid.
  • a back flush flow of acetic acid may then be flowed through the column at a flow rate and for a period of time sufficient to remove essentially all of the vapor from the inner chamber.
  • the removal of the vapor may include opening one or more of the sample ports.
  • the flow rate of the back flush flow of acetic acid is less than or equal to about 0.05 bed volumes per minute, and the period of time is less than or equal to about 30 minutes.
  • the purification resin is pneumatically directed into the inner chamber of the column by providing fluid communication between the inner chamber and a bottom outlet of a container comprising a slurry comprising the purification resin, followed by applying pressure to a headspace of the container in an amount sufficient to pneumatically transfer at least a portion of the slurry from the container into the inner chamber.
  • the inner chamber of the column and/or the headspace of the container is purged with an inert gas, e.g., nitrogen, to remove oxygen from the space (i.e., such that the space comprises less than 1 wt% oxygen) prior to charging the column with the purification resin.
  • an inert gas e.g., nitrogen
  • a process comprises carbonylating at least one member selected from the group consisting of methanol, dimethyl ether, and methyl acetate in the presence of 0.1 to less than 14 wt. water, a rhodium catalyst, methyl iodide and lithium iodide, to form a reaction medium comprising acetic acid in a reactor; separating the reaction medium into a liquid recycle stream and a vapor product stream; separating the vapor product stream in up to 2 distillation columns in a primary purification train to produce a crude acid product comprising acetic acid comprising lithium cations; contacting the crude acetic acid product with a first purification resin comprising a cationic exchanger in the acid form within a first treatment device to produce an intermediate acid product; and contacting the intermediate acetic acid product with a second purification resin comprising a metal-exchanged ion exchange resin having acid cation exchange sites within a second treatment device to produce a purified acetic acid
  • the process further comprises comparing the impurity concentration of at least one sample to a previously determined impurity concentration value, and determining if the impurity concentration of the sample indicates exhaustion of the purification resin at a point in the treatment device corresponding to the location of the sample port from which the sample was obtained.
  • the process further comprises stopping the flow of acetic acid through the treatment device prior to exhaustion of essentially all of the active purification resin present in the treatment device, regenerating at least a portion of the exhausted resin and resuming flow of the acetic acid stream through the treatment device to produce the purified acetic acid stream.
  • the metal-exchanged ion exchange resin comprises at least 1% strong acid exchange sites occupied by silver.
  • the crude acid product comprises up to 10 ppm lithium.
  • separating the vapor product stream comprises: distilling the vapor product stream in a first distillation column and taking a sidedraw to yield a distilled acetic acid product; and distilling the distilled acetic acid product in a second distillation column to produce a crude acid product comprising acetic acid and lithium cations.
  • the process further comprises a step of adding a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide to the distilled acetic acid product prior to distilling the distilled acetic acid product in a second distillation column; wherein at least a portion of the potassium is removed by the cationic exchanger in the acid form.
  • the crude acetic acid product is contacted with the cationic exchanger at a temperature from 50°C to 120°C.
  • the intermediate acetic acid product is contacted with the metal-exchanged ion exchange resin at a temperature from 50°C to 85°C; or a combination thereof.
  • the intermediate acetic acid product has a lithium ion concentration of less than 50 ppb.
  • the cationic exchanger in the acid form comprises a resin of acid-form strong acid cation exchange macroreticular, macroporous or mesoporous resins.
  • the process further comprises treating the purified acetic acid product with a cationic exchange resin to recover any silver, mercury, palladium or rhodium.
  • the water concentration in the reaction medium is controlled from 0.1 to 5 wt , based on the total amount of reaction medium present.
  • the process further comprises introducing a lithium compound selected from the group consisting of lithium acetate, lithium carboxylates, lithium carbonates, lithium hydroxide, and mixtures thereof into the reactor to maintain the concentration of lithium acetate from 0.3 to 0.7 wt in the reaction medium.
  • the process further comprises maintaining the hydrogen iodide concentration from 0.1 to 1.3 wt in the reaction medium; maintaining the rhodium catalyst concentration from 300 and 3000 wppm in the reaction medium; maintaining the water concentration from 0.1 to 4.1 wt in the reaction medium; maintaining the methyl acetate concentration from 0.6 to 4.1 wt in the reaction medium; or a combination thereof.
  • the process further comprises controlling a butyl acetate concentration in the acetic acid product at 10 wppm or less without directly removing butyl acetate from the acetic acid product.
  • the butyl acetate concentration is controlled by maintaining an acetaldehyde concentration at 1500 ppm or less in the reaction medium; controlling a temperature in the reactor from 150 to 250°C; controlling a hydrogen partial pressure in the reactor from 0.3 to 2 atm; controlling a rhodium catalyst concentration from 100 to 3000 wppm in the reaction medium; or a combination thereof.
  • the process further comprises controlling an ethyl iodide concentration in the reaction medium at less than or equal to 750 wppm.
  • the propionic acid concentration in the product acetic acid is less than 250 wppm, without directly removing propionic acid from the product acetic acid, wherein ethyl iodide in the reaction medium and propionic acid in the acetic acid product are present in a weight ratio from 3: 1 to 1:2; wherein acetaldehyde and ethyl iodide are present in the reaction medium in a weight ratio from 2: 1 to 20: 1; wherein an ethanol concentration in the methanol feed into the reactor is less than 150 wppm; or a combination thereof.
  • the ethyl iodide concentration in the reaction medium is controlled by adjusting at least one of a hydrogen partial pressure in the carbonylation reactor, a methyl acetate concentration in the reaction medium, and a methyl iodide concentration in the reaction medium.
  • Processes to produce acetic acid via methanol carbonylation can be conveniently divided into three main areas: the reaction systems and processes, the light ends recovery/acetic acid product separation systems and processes, and the product acetic acid purification systems and processes.
  • Acetic acid processes suitable for purposes herein to produce the vapor from the carbonylation reactor which is subsequently distilled in the light ends column to yield an acetic acid product as a sidedraw may vary in the systems and processes, including purification streams, recycle streams, the type and number of distillation columns utilized, the various purification processes employed, and the like.
  • process 100 A process to produce acetic acid according to embodiments disclosed herein, generally indicated as process 100, is shown schematically in FIG. 1.
  • This primary purification train receives the majority of the vapor flow from the reactor and obtains acetic acid as a final product.
  • the columns of the primary purification train include the light ends column and drying column.
  • This primary purification train may exclude columns whose main function is to remove minor components such as acetaldehyde, alkanes, and propionic acid.
  • the process for producing acetic acid may generate a cation that is collected in the crude acid product. These residual cations may be difficult to remove and in the final metal-exchange guard bed may adversely replace iodides. Thus, the final product may have unacceptable levels of iodides despite using a metal exchange guard bed.
  • the present invention provides process for removing the cations.
  • the source of the cation may come from a variety promoters, co-catalysts, additives, in situ reactions, etc. For example low water and low energy processes that involve the use of a promoter such as lithium iodide, which may form in situ following the addition of lithium acetate or other compatible lithium salts to the reaction mixture.
  • process streams may contain some quantity of lithium ions.
  • the crude acid product may contain larger alkyl iodide compounds, e.g., C 10 - C 14 alkyl iodides, in addition to cations, such as lithium.
  • alkyl iodide compounds e.g., C 10 - C 14 alkyl iodides
  • ppb there may be more than 10 ppb, e.g., more than 20 ppb, more than 50 ppb, more than 100 ppb, or more than 1 ppm of C 10 - C 14 alkyl iodides.
  • These higher alkyl iodides may be in addition to the usual shorter chain length iodide impurities found in the crude acid product of an iodide promoted carbonylation process, including methyl iodide, HI, and hexyl iodide.
  • the usual iodide impurities are typically removed from the crude acid product using a metal-exchanged strong acid ion exchange resin in which the metal is silver or mercury, for example.
  • the silver or mercury in the metal-exchanged strong acid ion exchange resin may be displaced by the residual lithium, resulting in lower resin capacity and efficiency and the potential for contaminating the product with silver or mercury.
  • the cation in the crude acid product may result from the use of organic alkali salt ligands, such as organic lithium salt ligands, such as those described CN101053841 and CN1349855, the entire contents and disclosure of which are hereby incorporated by reference.
  • organic alkali salt ligands such as organic lithium salt ligands, such as those described CN101053841 and CN1349855, the entire contents and disclosure of which are hereby incorporated by reference.
  • CN101053841 describes a ligand comprising lithium acetate or lithium oxalate.
  • CN1349855 describes a bimetallic catalyst having a metal lithium organic ligand coordinating cis-dicarbonyl rhodium structure.
  • the metal lithium organic ligand may be a pyridine derivative, such as lithium pyridine-2-formate, lithium pyridine-3-formate, lithium pyridine-4-formate, lithium pyridine-3- acetate, lithium pyridine-4-acetate, or lithium pyridine-3-propionate.
  • the lithium salt component of all of these ligands are believed to generate lithium iodide in situ within the reaction medium after exposure to methyl iodide at reaction temperature and pressure in the carbonylation reactor. At least some small portion of the lithium component will entrain into the purification system.
  • purification systems according to the instant disclosure may also remove lithium formed in situ from use of these types of organic ligands.
  • Cations may also be present as a result of the use of non-lithium salts, such as through the use of bimetallic Rh chelating catalysts that have an amine functionality, such as those described in CN1640543, the entire contents and disclosure of which is hereby incorporated by reference.
  • the cation species contains N and O donor atoms and is formed from aminobenzoic acid.
  • the amine may quaternize with methyl iodide in situ within the reaction medium at reaction temperature and pressure to form a quaternary nitrogen cation.
  • the quaternary nitrogen cation similar to the lithium cation, may be carried through with the crude acid product and may be removed using the present invention prior to the metal-exchange guard beds.
  • Embodiments include low water and low energy process for producing acetic acid by the carbonylation of methanol, dimethyl ether, and/or methyl acetate in the presence of 0.1 to less than 14 wt.% water, a metal catalyst, methyl iodide and lithium iodide.
  • a low- energy process which utilizes up to 2 distillation columns in the primary purification train (e.g., a light ends column and a water removal or dehydration column without employing a third "heavy ends column) and purifies the resulting acidic acid product with a cationic exchanger in the acid form to remove residual lithium ions followed by treatment with a metal-exchanged ion exchange resin having acid cation exchange sites comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium.
  • the metal-exchanged ion exchange resin can have at least 1% of the strong acid exchange sites occupied by silver, mercury, palladium, and/or rhodium, e.g., at least 1% silver, mercury, palladium, and/or rhodium, at least 5% silver, mercury, palladium, and/or rhodium, at least 10% silver, mercury, palladium, and/or rhodium, or at least 20% silver, mercury, palladium, and/or rhodium.
  • a cation exchanger to remove lithium prior to the use of a resin having metal-exchanged strong acid cation sites, the displacement of silver, mercury, palladium and/or rhodium from the metal- exchanged sites by the lithium is reduced or eliminated for a process that utilizes up to 2 distillation columns in the primary purification train.
  • other purification systems in addition to the primary purification train may utilize distillation columns to remove impurities from reactor components, such as an aldehyde removal system in which acetaldehyde and other PRCs are removed from the methyl iodide phase before returning the methyl iodide to the reaction medium.
  • Particularly preferred processes are those utilizing a cation exchanger for removing lithium followed by a silver-exchanged cationic substrate for removing iodides.
  • the crude acid product in many cases includes organic iodides with a C 10 or more aliphatic chain length which need to be removed. Sometimes more than 10% of the iodides present, e.g., more than 30% or even more than 50%, have an organic chain length of more than 10 carbon atoms.
  • Decyl iodides and dodecyl iodides are especially prevalent in the absence of heavy ends and other finishing apparatus and are difficult to remove from the product.
  • the silver-exchanged cationic substrates of the present invention typically remove over 90% of such iodides;
  • lithium/iodide removal treatment involves contacting the crude acid product with a cation exchanger to remove 95% or more of the lithium ions followed by contacting the crude acid product with a silver-exchanged sulfonic acid functionalized macroreticular ion exchange resin, wherein the product has an organic iodide content of greater than 100 ppb prior to treatment and an organic iodide content of less than 10 ppb after contacting the resin.
  • Lithium has also been found to be entrained in the crude acid product in the absence of heavy ends and other finishing apparatus. Even in very small amounts of 10 ppb of lithium in the crude acid product may cause problem for removing iodides. Up to 10 ppm of lithium by weight of the crude acid product, e.g., up to 5 ppm, up to 1 ppm, up to 500 ppb, up to 300 ppb, or up to 100 ppb, might be present in the acid-containing crude acid product exiting the drying column of an acetic acid process, e.g., the last column in the primary purification train.
  • the stream exiting the acid-form cationic exchanger may contain less than 50 ppb lithium, e.g., less than 10 ppb, or less than 5 ppb. Such removal of the lithium can greatly extend the life of the metal-exchanged resin.
  • the process to produce acetic acid 100 comprises a reaction system which includes the carbonylation reactor 104 from which a portion of the reaction medium is continuously removed via line 113 and subject to flash or low pressure distillation in a separation system, e.g., flasher 112, employed to separate the acetic acid and other volatile components from the reaction medium and recycle the non-volatile components back into the reaction medium via stream 110.
  • the volatile components of the reaction medium are then directed overhead via line 122 into the light ends recovery/acetic acid product separation systems and processes, which begin with light ends column 124.
  • a methanol-containing feed stream 101 and a carbon monoxide- containing feed stream 102 are directed into a liquid phase reaction medium of the carbonylation reactor 104, in which the carbonylation reaction occurs in a reaction medium comprising the catalyst, water, methyl iodide, methyl acetate, acetic acid, an iodide salt, HI, and other reaction medium components.
  • the carbonylation reactor 104 may be a stirred vessel, a bubble-column type vessel, or a combination thereof, within which the reacting liquid or slurry contents are maintained at levels consistent with normal operation.
  • carbon monoxide may be continuously introduced into the reaction medium of the carbonylation reactor, including below an agitator used to stir the contents.
  • the gaseous feed preferably is thoroughly dispersed through the reacting liquid by this stirring means.
  • the reactor system may further include a number of recycle lines, wherein various components are recycled back into the reaction medium from other parts of the process, and various vapor purge lines, which may be subject to additional processing and the like.
  • a gaseous purge stream 106 may be vented from reactor 104 to a scrubber system 139 to prevent buildup of gaseous by-products and to control a carbon monoxide partial pressure and/or a total reactor pressure.
  • the reactor system may further include a pump around loop 103 to control the temperature of the reactor
  • the reaction medium comprises a metal catalyst, or a Group 9 metal catalyst, or a catalyst comprising rhodium and/or iridium. In embodiments, the reaction medium comprises a rhodium catalyst.
  • the rhodium component of the catalyst system is believed to be present in the form of a coordination compound of rhodium with a halogen component providing at least one of the ligands of such coordination compound.
  • a coordination compound of rhodium with a halogen component providing at least one of the ligands of such coordination compound.
  • carbon monoxide will coordinate with rhodium.
  • the rhodium component of the catalyst system may be provided by introducing into the reaction zone rhodium in the form of rhodium metal, rhodium salts such as the oxides, acetates, iodides, carbonates, hydroxides, chlorides, and the like, or other compounds that result in the formation of a coordination compound of rhodium in the reaction environment.
  • the carbonylation catalyst comprises rhodium dispersed in a liquid reaction medium or supported on an inert solid. The rhodium can be introduced into the reaction system in any of many forms, and the exact nature of the rhodium moiety within the active catalyst complex may be uncertain.
  • the catalyst concentration is maintained in the reactor in amounts from about 200 to about 5000 parts per million (ppm) by weight, based on the total weight of the reaction medium.
  • the reaction medium may further comprise a halogen-containing catalyst promoter.
  • Suitable examples include organic halides, alkyl, aryl, and substituted alkyl or aryl halides.
  • the halogen-containing catalyst promoter is present in the form of an alkyl halide in which the alkyl radical corresponds to the alkyl radical of the feed alcohol which is being carbonylated.
  • the halide promoter will include methyl halide, or methyl iodide (Mel).
  • the reaction medium comprises greater than or equal to about 5 weight percent Mel, based on the total weight of the reaction medium.
  • the reaction medium comprises greater than or equal to about 5 weight percent and less than or equal to about 50 weight percent Mel. In embodiments, the reaction medium comprises greater than or equal to about 7 weight percent, or 10 weight percent Mel, and less than or equal to about 30 weight percent, or 20 weight percent Mel based on the total weight of the reaction medium.
  • the liquid reaction medium employed may include any solvent compatible with the catalyst system and may include pure alcohols, or mixtures of the alcohol feedstock and/or the product carboxylic acid and/or esters of these two compounds.
  • the solvent utilized in the liquid reaction medium comprises acetic acid (AcOH).
  • the reaction medium comprises greater than or equal to about 50 weight percent AcOH.
  • the reaction medium comprises greater than or equal to about 50 weight percent and less than or equal to about 90 weight percent AcOH.
  • the reaction medium comprises greater than or equal to about 50 weight percent, or 60 weight percent AcOH, and less than or equal to about 80 weight percent or 70 weight percent AcOH, based on the total weight of the reaction medium.
  • the reaction medium comprises at least a finite concentration of water. In embodiments, the reaction medium comprises a detectable amount of water. In embodiments, the reaction medium comprises greater than or equal to about 0.001 weight percent water. In embodiments, the reaction medium comprises greater than or equal to about 0.001 weight percent and less than or equal to about 14 weight percent water. In embodiments, the reaction medium comprises greater than or equal to about 0.05 weight percent, or 0.1 weight percent, or 0.5 weight percent, or 1 weight percent, or 2 weight percent, or 3 weight percent, or 4 weight percent water, and less than or equal to about 10 weight percent or 5 weight percent water, based on the total weight of the reaction medium.
  • the reaction medium further comprises an ester of the carboxylic acid product and the alcohol used in the carbonylation.
  • the reaction medium comprises methyl acetate.
  • the reaction medium comprises greater than or equal to about 0.5 weight percent methyl acetate (MeAc).
  • the reaction medium comprises greater than or equal to about 1 weight percent and less than or equal to about 50 weight percent MeAc.
  • the reaction medium comprises greater than or equal to about 1.5 weight percent, or 2 weight percent, or 3 weight percent MeAc, and less than or equal to about 20 weight percent or 10 weight percent MeAc, based on the total weight of the reaction medium.
  • the reaction medium further comprises an additional iodide ion that is over and above the iodide ion that is present as hydrogen iodide.
  • the iodide ion concentration is provided by an iodide salt, or lithium iodide (Lil).
  • the reaction medium is maintained under low water concentrations wherein methyl acetate and lithium iodide are present in concentrations sufficient to act as rate promoters (cf. US5001259).
  • the iodide ion concentration in the reaction medium results from a metal iodide salt, or an iodide salt of an organic cation, or cations based on quaternary amines, phosphines, and the like.
  • the iodide is a metal salt, a Group I or Group 2 iodide salt.
  • the reaction medium comprises an alkali metal iodide, or lithium iodide.
  • the iodide concentration is over and above the iodide ion present as hydrogen iodide.
  • the reaction medium comprises an amount of an iodide salt, or lithium iodide, in an amount sufficient to produce a total iodide ion concentration greater than about 2 weight percent. In embodiments, the reaction medium comprises an amount of an iodide salt, or lithium iodide, in an amount sufficient to produce a total iodide ion concentration greater than or equal to about 2 weight percent and less than or equal to about 40 weight percent, based on the total weight of the reaction medium.
  • the reaction medium comprises greater than or equal to about 5 weight percent, or 10 weight percent, or 15 weight percent iodide ion, and less than or equal to about 30 weight percent or 20 weight percent iodide ion, based on the total weight of the reaction medium.
  • the reaction medium may further comprise hydrogen, determined according to a hydrogen partial pressure present in the reactor.
  • the partial pressure of hydrogen in the reactor is greater than or equal to about 0.7 kPa (0.1 psia), or 3.5 kPa (0.5psia), or 6.9 kPa (1 psia), and less than or equal to about 1.03 MPa (150 psia), or 689 kPa (100 psia), or 345 kPa (50 psia), or 138 kPa (20 psia).
  • the reactor temperature i.e., the temperature of the reaction medium, is greater than or equal to about 150°C. In embodiments, the reactor temperature is greater than or equal to about 150°C and less than or equal to about 250°C. In embodiments, the reactor temperature is greater than or equal to about 180° and less than or equal to about 220°C.
  • the carbon monoxide partial pressure in the reactor is greater than or equal to about 200 kPa. In embodiments, the CO partial pressure is greater than or equal to about 200 kPa and less than or equal to about 3 MPa.
  • the CO partial pressure in the reactor is greater than or equal to about the 300 kPa, or 400 kPa, or 500 kPa and less than or equal to about 2 MPa, or 1 MPa.
  • the total reactor pressure represents the combined partial pressure of all reactants, products, and by-products present therein. In embodiments, the total reactor pressure is greater than or equal to about 1 MPa and less than or equal to about 4 MPa.
  • the liquid reaction medium is drawn off from the carbonylation reactor 104 and directed into the flasher 112 having a lower pressure than is present in the reactor at a rate sufficient to maintain a constant level therein, and is introduced to the flasher 112 at a point intermediate between the top and bottom thereof.
  • the less volatile components namely the catalyst solution
  • the base stream 110 predominantly acetic acid containing the rhodium and the iodide salt along with lesser quantities of methyl acetate, methyl iodide, acetic acid and water
  • the overhead of the flasher 122 comprises largely the product acetic acid along with methyl iodide, methyl acetate, water, and PRCs.
  • a portion of the carbon monoxide along with gaseous by-products such as methane, hydrogen, carbon dioxide, and the like may also exit the top of the flasher.
  • the overhead stream from flasher 112 is directed to the light ends column 124, also referred to in the art as the stripper column, as stream 122, where distillation yields a low-boiling overhead vapor stream 126, also referred to herein as a first overhead stream 126, and a purified acetic acid product stream 128, which in embodiments is removed as a side stream.
  • the light ends column 124 further produces a high boiling residuum stream 116, which may be subject to further purification and/or may be recycled back into the reaction medium.
  • the first overhead 126 is condensed and then directed into an overhead phase separation unit 134, also referred to herein an overhead decanter.
  • the first overhead 126 comprises methyl iodide, methyl acetate, acetic acid, water, and at least one PRC.
  • the condensed first overhead stream 126 is separated into a light aqueous phase 135 comprising water, acetic acid, methyl iodide, methyl acetate, and at least one permanganate reducing compound (PRC), e.g., acetaldehyde; and a heavy phase 137 comprising methyl iodide, methyl acetate, which may also comprise at least one PRC.
  • PRC permanganate reducing compound
  • At least a portion of the heavy phase 137, at least a portion of the light phase 135, or a combination thereof is returned to the reaction medium via lines 118 and 114, respectively.
  • a portion of the light phase stream 135 may be recycled to the reaction medium in stream 114, to provide water to the reaction medium as required.
  • the heavy phase 137 is recirculated to the reactor via 118.
  • the light phase 135, the heavy phase 137, or a combination thereof is directed to one or more purification processes 108, e.g., an aldehyde removal system, via stream 142.
  • the subsequently purified stream is then returned to the process via one or more streams, collectively referred to as 155.
  • compositions of light liquid phase 135 may vary widely, some exemplary compositions are provided below in Table 1.
  • overhead decanter 134 is arranged and constructed to maintain a low interface level to prevent an excess hold up of methyl iodide.
  • specific compositions of heavy liquid phase 137 may vary widely, some ex emplary compositions are provided below in Table 2.
  • Methyl Iodide 40-98 50-95 60-85 a portion of light liquid phase 135 and/or heavy liquid phase 137 may be separated and directed to acetaldehyde or PRC removal system to recover methyl iodide and methyl acetate, while removing acetaldehyde.
  • light liquid phase 135 and/or heavy liquid phase 137 each contain PRC's and the process may include removing carbonyl impurities, such as acetaldehyde, that deteriorate the quality of the acetic acid product and may be removed in suitable impurity removal columns and absorbers as described in US Pat. Nos.
  • Carbonyl impurities such as acetaldehyde, may react with iodide catalyst promoters to form alkyl iodides, e.g., ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, etc.
  • alkyl iodides e.g., ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, etc.
  • the portion of light liquid phase 135 and/or heavy liquid phase 137 fed to the acetaldehyde or PRC removal system may vary from 1% to 99% of the mass flow of either the light liquid phase 133 and/or heavy liquid phase 134, e.g., from 1 to 50%, from 2 to 45%, from 5 to 40%, 5 to 30% or 5 to 20%. Also in some embodiments, a portion of both the light liquid phase 135 and heavy liquid phase 137 may be fed to the acetaldehyde or PRC removal system. The portion of the light liquid phase 135 not fed to the acetaldehyde or PRC removal system may be refluxed to the first column or recycled to the reactor, as described herein.
  • the portion of the heavy liquid phase 137 not fed to the acetaldehyde or PRC removal system may be recycled to the reactor. Although a portion of heavy liquid phase 137 may be refluxed to the first column, it is more desirable to return the methyl iodide enriched heavy liquid phase 137 to the reactor.
  • a portion of light liquid phase 135 and/or heavy liquid phase 137 is fed to a distillation column which enriches the overhead thereof to have acetaldehyde and methyl iodide.
  • a distillation column which enriches the overhead thereof to have acetaldehyde and methyl iodide.
  • the overhead of the second column may be enriched in acetaldehyde and methyl iodide.
  • Dimethyl ether which may be formed in-situ, may also be present in the overhead.
  • the overhead may be subject to one or more extraction stages to remove a raffinate enriched in methyl iodide and an extractant. A portion of the raffinate may be returned to the distillation column, first column, overhead decanter and/or reactor.
  • the heavy liquid phase 137 when the heavy liquid phase 137 is treated in the PRC removal system, it may be desirable to return a portion the raffinate to either the distillation column or reactor.
  • the extractant may be further distilled to remove water, which is returned to the one or more extraction stages, in which contains more methyl acetate and methyl iodide than light liquid phase 135, may also be recycled to reactor 104 and/or refluxed to first column 124.
  • Suitable purification processes include those disclosed in US6143930, US6339171, US7223883, US7223886, US8076507, US20130303800, US20130310603, US20090036710, US20090062525, US20120132515, US20130026458, US201300116470, US20130204014, US20130261334, US20130264186, or US201330281735, all of which are incorporated by reference herein.
  • acetic acid stream 128 may be subjected to further purification, such as in a drying column 130, wherein the acetic acid is collected as a column bottom and the aqueous overhead is collected in an overhead decanter 148, a portion of which may be refluxed back into the drying column 130 prior to being returned to the reactor 104.
  • Other embodiments include directing the acetic acid to a heavy ends column (cf. WO0216297), and/or contacted with one or more absorbent, adsorbent, or ion exchange resins in a resin bed or guard column 200 to remove various impurities (cf. US6657078), and the like in the product purification section of the process, as described more fully herein.
  • drying column 130 separates acetic acid sidedraw 128 into overhead stream comprised primarily of water and bottoms stream comprised primarily of acetic acid.
  • Overhead stream is cooled and condensed in a phase separation unit, e.g., decanter 148, to form a light phase and a heavy phase.
  • a portion of the light phase is refluxed and the remainder of the light phase is returned to the reactor.
  • the heavy phase which typically is an emulsion comprising water and methyl iodide, preferably is returned in its entirety to the reactor.
  • Exemplary compositions for the light phase of the drying column overhead are provided below in Table 3. TABLE 3
  • an alkali component such as KOH can be added to sidedraw 128 prior to entering the drying column 130.
  • the alkali component might also be added to the drying column 130 at the same height level as the stream 128 entering the drying column 130 or at a height above the height level height level as the stream 128 entering the drying column 130. Such addition can neutralize HI in the column.
  • the drying column bottoms stream may comprise or consists essentially of acetic acid.
  • drying column bottoms stream comprises acetic acid in an amount greater than 90 wt.%, e.g., greater than 95 wt.% or greater than 98 wt.%.
  • this stream will also be essentially anhydrous, for example, containing less than 0.15 wt.% water, e.g., less than 0.12 wt.% water or less than 0.1 wt.% water.
  • the stream may contain varying levels of impurities.
  • the crude acid product is withdrawn as a residue in drying column bottoms stream 146.
  • the crude acid product from the drying column 130 may be taken from a side stream at a position slightly above the bottom of the column 130. This side stream may be withdrawn in the liquid or vapor phase. When withdrawn in the vapor phase further condensing and cooling may be necessary prior to removing alkaline contaminants, e.g., lithium contaminants.
  • the crude acid product may be taken as a side stream from a lower part of the column, while a residue stream from the base of the drying column 130 is withdrawn and removed or recycled. This side stream contains the crude acetic acid product that is sent to cationic exchange resin to remove lithium.
  • the crude acid product produced by the drying column 130 is further processed, by passing through a series of metal functionalized iodide removal ion exchange resins, prior to being stored or transported for commercial use.
  • the process for producing acetic acid further includes introducing a lithium compound into the reactor to maintain the concentration of lithium acetate in an amount from 0.3 to 0.7 wt in the reaction medium.
  • an amount of the lithium compound is introduced into the reactor to maintain the concentration of hydrogen iodide in an amount from 0.1 to 1.3 wt in the reaction medium.
  • the concentration of the rhodium catalyst is maintained in an amount from 300 to 3000 wppm in the reaction medium, the concentration of water is maintained in amount from 0.1 to 4.1 wt in the reaction medium, and the concentration of methyl acetate is maintained from 0.6 to 4.1 wt in the reaction medium, based on the total weight of the reaction medium present within the carbonylation reactor.
  • the lithium compound introduced into the reactor is selected from the group consisting of lithium acetate, lithium carboxylates, lithium carbonates, lithium hydroxide, other organic lithium salts, and mixtures thereof.
  • the lithium compound is soluble in the reaction medium.
  • lithium acetate dihydrate may be used as the source of the lithium compound.
  • Lithium acetate reacts with hydrogen iodide according to the following equilibrium reaction (I) to form lithium iodide and acetic acid:
  • Lithium acetate is thought to provide improved control of hydrogen iodide concentration relative to other acetates, such as methyl acetate, present in the reaction medium.
  • lithium acetate is a conjugate base of acetic acid and thus reactive toward hydrogen iodide via an acid - base reaction. This property is thought to result in an equilibrium of the reaction (I) which favors reaction products over and above that produced by the corresponding equilibrium of methyl acetate and hydrogen iodide. This improved equilibrium is favored by water concentrations of less than 4.1 wt in the reaction medium.
  • lithium acetate is at least three times more effective than methyl acetate in promoting methyl iodide oxidative addition to the rhodium [I] complex.
  • the concentration of lithium acetate in the reaction medium is maintained at greater than or equal to 0.3 wt.%, or greater than or equal to 0.35 wt.%, or greater than or equal to 0.4 wt.%, or greater than or equal to 0.45 wt.%, or greater than or equal to 0.5 wt.%, and/or in embodiments, the concentration of lithium acetate in the reaction medium is maintained at less than or equal to 0.7 wt.%, or less than or equal to 0.65 wt.%, or less than or equal to 0.6 wt.%, or less than or equal to 0.55 wt.%, when determined according to perchloric acid titration to a potentiometric endpoint.
  • the lithium compound may be introduced continuously or intermittently into the reaction medium. -In embodiments, the lithium compound is introduced during reactor start up. In embodiments, the lithium compound is introduced intermittently to replace entrainment losses.
  • the process may further comprise maintaining a butyl acetate concentration in the acetic acid product at 10 wppm or less without directly removing butyl acetate from the product acetic acid.
  • the butyl acetate concentration in the final acetic acid product may be maintained below 10 ppm by removing acetaldehyde from the reaction medium, e.g., removing acetaldehyde from a stream derived from the reaction medium, and/or by controlling the reaction temperature, and/or the hydrogen partial pressure, and/or the metal catalyst concentration in the reaction medium.
  • the butyl acetate concentration in the final acetic acid product is maintained by controlling one or more of the carbonylation reaction temperature from 150°C to 250°C, the hydrogen partial pressure in the carbonylation reactor at from 0.3 to 2 atm, the rhodium metal catalyst concentration in the reaction medium at from 100 to 3000 wppm, based on the total weight of the reaction medium, and/or the acetaldehyde concentration in the reaction medium at 1500 ppm or less.
  • the acetic acid product formed according to embodiments of the process disclosed herein has a butyl acetate concentration of less than or equal to 10 wppm, or less than or equal to 9 wppm, or less than or equal to 8 wppm, or less than or equal to 6 wppm, or less than or equal to 2 wppm, based on the total weight of the acetic acid product.
  • the acetic acid product is substantially free of butyl acetate, i.e., a butyl acetate concentration of less than 0.05 wppm or is non-detectable by detection means known in the art.
  • the acetic acid product may also have a propionic acid concentration of less than 250 wppm, or less than 225 ppm, or less than 200 wppm.
  • the butyl acetate concentration in the acetic acid product may be controlled by controlling the concentration of acetaldehyde in the reaction medium. While not wishing to be bound by theory, butyl acetate is thought to be a by-product caused by aldol condensation of acetaldehyde. Applicant has discovered that by maintaining the acetaldehyde concentration in the reaction medium at less than 1500 wppm, the concentration of butyl acetate in the final acetic acid product may be controlled below 10 wppm.
  • the acetaldehyde concentration in the reaction medium is maintained at less than or equal to 1500 wppm, or less than or equal to 900 wppm, or less than or equal to 500 wppm, or less than or equal to 400 wppm, based on the total weight of the reaction medium.
  • the butyl acetate concentration in the acetic acid product may be controlled by controlling the reaction temperature of the carbonylation reactor at a temperature greater than or equal to 150°C, or 180°C, and less than or equal to 250°C, or 225°C; and/or the hydrogen partial pressure in the carbonylation reactor may be controlled at greater than or equal to 0.3 atm, or 0.35 atm, or 0.4 atm, or 0.5 atm, and less than or equal to 2 atm, or 1.5 atm, or 1 atm.
  • the hydrogen partial pressure may be controlled by modifying the amount of hydrogen present in the carbon monoxide source and/or by increasing or decreasing the reactor vent flows to obtain the desired hydrogen partial pressure within the carbonylation reactor.
  • the concentration of propionic acid in the final acetic acid product may be affected by the concentration butyl acetate in the acetic acid product. Accordingly, by controlling the butyl acetate concentration in the final acetic acid product to 10 wppm or less, the concentration of propionic acid in the final acetic acid product may be controlled to less than 250 wppm, or less than 225 ppm, or less than 200 wppm. Likewise, by controlling the ethanol content in the reactor feed, which may be present as an impurity in the methanol source, the propionic acid and butyl acetate concentrations in the final acetic acid product may also be controlled.
  • the concentration of ethanol in the methanol feed to the carbonylation reactor is controlled to less than or equal to 150 wppm. In embodiments, if present, the ethanol concentration in the methanol feed to the reactor is less than or equal to 100 wppm, or 50 wppm, or 25 wppm.
  • ethyl iodide may be affected by numerous variables, including the concentration of acetaldehyde, ethyl acetate, methyl acetate and methyl iodide in the reaction medium. Additionally, ethanol content in the methanol source, hydrogen partial pressure and hydrogen content in the carbon monoxide source have been discovered to affect ethyl iodide concentration in the reaction medium and, consequently, propionic acid concentration in the final acetic acid product.
  • the concentration of ethyl iodide in the reaction medium is maintained/controlled to be less than or equal to 750 wppm, or less than or equal to 650 wppm, or less than or equal to 550 wppm, or less than or equal to 450 wppm, or less than or equal to 350 wppm.
  • the concentration of ethyl iodide in the reaction medium is maintained/controlled at greater than or equal to 1 wppm, or 5 wppm, or 10 wppm, or 20 wppm, or 25 wppm, and less than or equal to 650 wppm, or 550 wppm, or 450 wppm, or 350 wppm.
  • the propionic acid concentration in the acetic acid product may further be maintained below 250 wppm by maintaining the ethyl iodide concentration in the reaction medium at less than or equal to 750 wppm without removing propionic acid from the acetic acid product.
  • the ethyl iodide concentration in the reaction medium and propionic acid in the acetic acid product may be present in a weight ratio from 3: 1 to 1:2, or from 5:2 to 1:2, or from 2: 1 to 1:2.
  • the acetaldehyde: ethyl iodide concentration in the reaction medium is maintained at a weight ratio from 2: 1 to 20: 1, or from 15: 1 to 2: 1, or from 9: 1 to 2: 1.
  • the ethyl iodide concentration in the reaction medium may be maintained by controlling at least one of the hydrogen partial pressure, the methyl acetate concentration, the methyl iodide concentration, and/or the acetaldehyde concentration in the reaction medium.
  • the product acetic acid streams may be contaminated with halides (e.g., iodides) and lithium may be contacted with an acid-form cationic exchange resin followed by a metal-exchanged ion exchange resin having acid cation exchange sites comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium under a range of operating conditions.
  • halides e.g., iodides
  • lithium may be contacted with an acid-form cationic exchange resin followed by a metal-exchanged ion exchange resin having acid cation exchange sites comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium under a range of operating conditions.
  • the ion exchange resin compositions are provided in fixed beds. The use of fixed iodide removal beds to purify contaminated carboxylic acid streams is well documented in the art (see, for example, US Patent Nos.
  • a contaminated liquid carboxylic acid stream is contacted with the aforementioned ion exchange resin compositions, by flowing through a series of static fixed beds.
  • the lithium contaminants are removed by the cationic exchanger in the acid form.
  • the halide contaminants e.g., iodide contaminants, are then removed by reaction with the metal of the metal-exchanged ion exchange resin to form metal iodides.
  • hydrocarbon moieties e.g., methyl groups that may be associated with the iodide may esterify the carboxylic acid.
  • methyl acetate would be produced as a byproduct of the iodide removal.
  • the formation of this esterification product typically does not have a deleterious effect on the treated carboxylic acid stream.
  • Suitable acid-form cation exchangers for removing metal ion contaminants in the present invention may comprise strong acid cation exchange resins, for example strong acid macroreticular or macroporous resins, for example Amberlyst® 15 resin (DOW), Purolite C145, or Purolite CT145.
  • the resin may also be an acid-form strong acid cation exchange mesoporous resin. Chelating resins and zeolites may also be used.
  • Suitably stable ion exchange resins utilized in connection with the present invention for preparing silver or mercury-exchanged resins for iodide removal typically are of the "RS03H" type classified as “strong acid,” that is, sulfonic acid, cation exchange resins of the macroreticular (macroporous) type.
  • Particularly suitable ion exchange substrates include Amberlyst® 15, Amberlyst® 35 and Amberlyst® 36 resins (DOW) suitable for use at elevated temperatures.
  • Other stable ion exchange substrates such as zeolites may be employed, provided that the material is stable in the organic medium at the conditions of interest, that is, will not chemically decompose or release silver or mercury into the organic medium in unacceptable amounts.
  • Zeolite cationic exchange substrates are disclosed, for example, in U.S. Pat. No. 5,962,735, the disclosure of which is incorporated herein by reference.
  • the silver or mercury exchanged cationic substrate may tend to release small amounts of silver or mercury on the order of 500 ppb or less and thus the silver or mercury exchanged substrate is chemically stable under the conditions of interest. More preferably, silver losses are less than 100 ppb into the organic medium and still more preferably less than 20 ppb into the organic medium. Silver losses may be slightly higher upon start up. In any event, if so desired a bed of acid form cationic material maybe placed downstream of the silver or mercury exchange material in addition to the bed of acid form cationic material upstream of the silver or mercury exchange material, to catch any silver or mercury released.
  • the pressures during the contacting steps with the exchange resins are limited only by the physical strength of the resins.
  • the contacting is conducted at pressures ranging from 0.1 MPa to 1 MPa, e.g., from 0.1 MPa to 0.8 MPa or from 0.1 MPa to 0.5 MPa.
  • both pressure and temperature preferably may be established so that the contaminated carboxylic acid stream is processed as a liquid.
  • the temperature may range from 17°C (the freezing point of acetic acid) and 118°C (the boiling point of acetic acid).
  • the temperature of the contacting step preferably is kept low enough to minimize resin degradation.
  • the contacting is conducted at a temperature ranging from 25°C to 120°C, e.g., from 25°C to 100°C or from 50°C to 100°C.
  • Some cationic macroreticular resins typically begin significant degrading (via the mechanism of acid-catalyzed aromatic desulfonation) at temperatures of 150°C.
  • Carboxylic acids having up to 5 carbon atoms, e.g., up to 3 carbon atoms remain liquid at these temperatures.
  • the temperature during the contacting should be maintained below the degradation temperature of the resin utilized.
  • the operating temperature is kept below temperature limit of the resin, consistent with liquid phase operation and the desired kinetics for lithium and/or halide removal.
  • the configuration of the resin beds within an acetic acid purification train may vary, but the cationic exchanger should be upstream of the metal-exchanged resin.
  • the resin beds are configured after a final drying column.
  • the resin beds are configured in a position wherein the temperature of the crude acid product is low, e.g., less than 120°C or less than 100°C.
  • the stream contacting the acid-form cationic exchange resin and the stream contacting the metal-exchanged resin can be adjusted to the same or different temperatures.
  • the stream contacting the acid-form cationic exchange resin can be adjusted to a temperature of from 25°C to 120°C, e.g., 25°C to 85°C, 40°C to 70°C, e.g., 40°C to 60°C, while the stream contacting the metal-exchanged resin can be adjusted to a temperature of from 50°C to 100°C, e.g., 50°C to 85°C, 55°C to 75°C, or 60°C to 70°C.
  • lower temperature operation provides for less corrosion as compared to higher temperature operation.
  • Lower temperature operation provides for less formation of corrosion metal contaminants, which, as discussed above, may decrease overall resin life.
  • vessels advantageously need not be made from expensive corrosion-resistant metals, and lower grade metals, e.g., standard stainless steel, may be used.
  • drying column bottoms stream is first passed through cationic exchange resin bed 200 to remove lithium ions.
  • cationic exchange resin bed 200 may also remove other cations present in the stream, such as potassium, if added to drying column 130 as a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide, and corrosion metals.
  • the resulting exchanged stream e.g., an intermediate acid product may then be passed through a metal-exchanged ion exchange resin bed having acid cation exchange sites comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium to remove iodides from the stream to produce a purified product 146.
  • a metal-exchanged ion exchange resin bed having acid cation exchange sites comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium to remove iodides from the stream to produce a purified product 146.
  • the purification resins are shown via block 200, it should be understood that a plurality of metal- exchanged ion exchange resin beds may be used in series or parallel.
  • heat exchangers may be located before either resin bed to adjust the temperature of the stream 146 and 182 to the appropriate temperature before contacting the resin beds.
  • a crude acetic acid product may be fed to a cationic exchange resin bed from a drying column side stream.
  • Heat exchangers or condensers may be located before either resin bed to adjust the temperature of the stream to the appropriate temperature before contacting the resin beds.
  • the flow rate through the resin beds ranges from 0.1 bed volumes per hour ("BV/hr") to 50 BV/hr, e.g., 1 BV/hr to 20 BV/hr or from 6 BV/hr to 10 BV/hr.
  • a bed volume of organic medium is a volume of the medium equal to the volume occupied by the resin bed.
  • a flow rate of 1 BV/hr means that a quantity of organic liquid equal to the volume occupied by the resin bed passes through the resin bed in a one hour time period.
  • a purified acetic acid composition is obtained as a result of the resin bed treatment.
  • the purified acetic acid composition in one embodiment, comprises less than 100 wppb, iodides, e.g., less than 90 wppb, less than 50 wppb, or less than 25 wppb. In one embodiment, the purified acetic acid composition comprises less than 100 wppb lithium, e.g., less than 50 wppb, less than 20 wppb, or less than 10 wppb. In terms of ranges, the purified acetic acid composition may comprise from 0 to 100 wppb iodides, e.g., from 0 to 50 wppb; and/or from 0 to 100 wppb lithium, e.g., from 1 to 50 wppb.
  • the resin beds remove at least 25 wt of the iodides from the crude acetic acid product, e.g., at least 50 wt or at least 75 wt . In one embodiment, the resin beds remove at least 25 wt of the lithium from the crude acetic acid product, e.g., at least 50 wt or at least 75 wt .
  • the product acetic acid, or one of more intermediate of recycle streams of the process may be contacted with one or more absorbent, adsorbent, or ion exchange resins, collectively referred to herein as purification resins.
  • the acetic acid is contacted within a resin bed or guard column 200 to remove various impurities to produce the final acetic acid product.
  • Impurities removed by the purification resins may include alkyl iodides.
  • alkyl iodides comprises from 1 to about 20 carbon atoms.
  • Other impurities include various corrosion metals such as chromium, nickel, iron, and the like.
  • Suitable purification resins for purposes herein include macro reticulated, strong acid cationic exchange resins with at least one percent of their active sites converted to the silver or mercury form.
  • the amount of silver or mercury associated with the resin may be from 1 to 100% of the active sites of the resin, or about 25 percent to about 75 percent, or at least about 50 percent of the active sites may be converted to the silver or mercury form (cf. US4615806, the contents of which are fully incorporated by reference herein).
  • Other suitable examples include US5139981, which is directed to removing iodides from liquid carboxylic acid contaminated with a halide impurity by contacting the liquid halide contaminant acid with a silver (I) exchanged macroreticular resin.
  • Suitable examples of purification resins include Amberlyst(R) 15 resin (Rohm and Haas), zeolite cationic ion exchange substrates (cf. US596273), and the like.
  • Other suitable purification resins and methods include those disclosed in US5227524, US5801279, US5220058, EP0685445, and US6657078, the contents of which are fully incorporated by reference herein.
  • the acetic acid is contacted with the purification resin at a temperature of at least about 50°C, or about 60°C to about 100°C, or at temperatures greater than or equal to about 150°C depending on the type of purification resin employed.
  • the flow rate of acetic acid through the column may be from about 0.5 to about 20 bed volumes per hour (BV/hr), wherein a bed volume is defined as the volume occupied by the resin in the bed. In embodiments, the flow rate may be from about 6 to about 10 BV/hr, or about 7 to 8 BV/hr.
  • the column may comprise an anionic guard bed, comprising a pyridine or pyrrolidone resin.
  • pyridine resin refers to a polymer containing substituted or non- substituted pyridine rings or substituted or non- substituted, pyridine-containing polycondensed rings such as quinoline rings.
  • the resins may comprise a high degree of crosslinking, i.e., greater than 10 wt .
  • the substituents include those inert to the methanol carbonylation process conditions such as an alkyl group and alkoxy group.
  • Suitable examples of the insoluble, pyridine ring-containing polymers include those obtained by reaction of vinylpyridine with a divinyl monomer or by reaction of vinylpyridine with a divinyl monomer- containing vinyl monomer, such as copolymers of 4-vinylpyridine and divinylbenzene, copolymers of 2-vinylpyridine and divinylbenzene, copolymers of styrene, vinylbenzene and divinylbenzene, copolymers of vinylmethylpyridine and divinylbenzene and copolymers of vinylpyridine, methyl acrylate and ethyl diacrylate (cf. US5334755, the disclosure of which is incorporated herein by reference).
  • Suitable "pyrrolidone resin”, "pyrrolidone ring-containing polymer”, pyrrolidone polymer and the like include polymers containing substituted or non-substituted pyrrolidone rings.
  • the substituents may include those inert to the methanol carbonylation medium such as alkyl groups or alkoxy groups.
  • Examples of insoluble, pyrrolidone ring-containing polymer include those obtained by reaction of vinyl pyrrolidone with a di-vinyl monomer-containing vinyl monomer such as a co-polymer of a vinyl pyrrolidone and divinyl benzene.
  • Suitable examples of pyrrolidone polymers include those disclosed in US5466874, US5286826, US4786699, US4139688, the disclosures of which are incorporated herein by reference, and those available under the trade name of Reillex(R) from Reilley Tar and Chemical Corporation of Indianapolis, USA.
  • the nitrogen heterocyclic ring-containing polymer may be crosslinked by at least 10%, or at least 15% or 20%, and less than 50%, or 60%, or 75% to provide mechanical strength, wherein the "degree of crosslinking" refers to the content, in terms of % by weight, of the divinyl monomer or other crosslinking moiety.
  • suitable pyridine or pyrrolidone insoluble polymers include free base forms, and/or N-oxide forms, and/or quaternized forms.
  • the insoluble, pyridine or pyrrolidone ring-containing polymer may be in a bead or granular form, or a spherical form, having a particle diameter of 0.01-2 mm, or 0.1-1 mm, or 0.25-0.7 mm.
  • Commercially available pyridine-containing polymers include Reillex-425 (Reilly Tar and Chemical Corporation), KEX- 316, KeX-501 and KEX-212 (products of Koei Chemical Co., Ltd.), and the like.
  • product acetic acid is withdrawn from drying column 130 at or near the bottom of the column via stream 146 and contacted with one or more resins in column comprising the purification resin.
  • the column comprising the purification resin may be referred to as a purification column, as a guard bed assembly or column, or simply as a column. These terms are used interchangeably herein.
  • the purification or guard bed assembly is generally represented in FIG. 1 as 200.
  • the guard bed assembly 200 may comprise one or more treatment devices, e.g., column 202, and column 204, each comprising an inlet end 206 and 210, respectively, and an outlet end 208 and 212, respectively.
  • the inlets are separated from the outlets by an inner chamber 214 and 216.
  • An amount of the purification resin 218 and 220 is located within the inner chamber.
  • the acetic acid from the process, having an impurity at a first concentration 146 is directed through the inner chamber 214 and 216 in contact with the purification resin 218 and 220 at a temperature and flow rate sufficient to produce a purified acetic acid stream 222 in which the impurity is present, if at all, at a second concentration which is less than the first impurity concentration. Accordingly, the second concentration of the impurity may be zero or otherwise non-detectable.
  • the guard bed assembly may further comprise heat exchangers 224 and 226, which control the temperature at which the acetic acid contacts the purification resin.
  • the columns 202 and 204 are plug flow columns, which flow downhill with gravity from top to the bottom. However, a device which flows against gravity from a bottom inlet end to a top outlet end is also contemplated.
  • a first column 202 may comprise an outlet end 208 in direct fluid communication with an inlet end 210 of a second column 204.
  • the conduits between the various devices may be arranged such that any one of a plurality of the columns may be the first treatment device, and any of the remaining columns may be subsequently disposed in series.
  • a plurality of columns may be arranged in a parallel configuration.
  • the purification resin 218 of the first column 202 may be different than the purification resin 220 in the second column 204, and/or the temperature of the first column 202 may be different than the temperature of the second column 204, and/or a volume of the inner chamber 214 of the first column 202 may be different than a volume of the inner chamber 216 of the second column 204.
  • the column 400 comprises an inner chamber 402 bound by a plurality of sides 404 radially arranged about a central axis 406.
  • the column 400 comprises an infinite number of sides, i.e., has a circular cross-section.
  • the column 400 further comprises an inlet end 408 in fluid communication with, and longitudinally separated from, an outlet end 410 through the inner chamber 402.
  • column 400 further comprises a plurality of sampling ports 412 disposed through at least one of the sides 404.
  • the sampling ports may be solid sampling ports, liquid sampling ports, or a combination thereof.
  • each sample port 412 comprises a first open flow path 414 between a sample inlet 416 located within the inner chamber 402 and a first flow control element 418 operable between an open position (as shown in flow control element 420, e.g., a ball of a ball valve), and a closed position (as shown in flow control element 418), the flow control element being located external to the inner chamber 402, in an external environment 422.
  • the term "open flow path” refers to a flow path dimensioned and arranged to allow both liquid and solid matter to pass through it. Accordingly, the relative size of the open flow path must be determined relative to the average particle size of the solid or semi-solid material which will pass there-through.
  • the flow control element When the flow control element is in the open position, there exists fluid communication between the inner chamber 402 and the external environment 422.
  • the first flow path 414 and the second flow path 424 are each in fluid communication with an external environment 422 when the corresponding flow control element 418 and 420, respectively, is in the open position.
  • the flow control element When the flow control element is in the closed position, fluid communication between the inner chamber 402 and the external environment 422 is prevented.
  • the sample port further comprises a second flow path 424 comprising a porous element 426 disposed between the sample inlet 416 and a second flow control element 420 operable between an open position and a closed position located external to the inner chamber 402.
  • the second flow path 424 comprises a portion of the first flow path 414 between the sample inlet 416 and the first flow control element 418. Accordingly, in
  • the second flow path may be in a "T-plan” or "Y-plan” orientation off of the first flow path such that a sample exiting through the first control element 418 is taken from the same place in the inner chamber 402 as a sample exiting through the second flow control element 420.
  • the first flow path 414, the second flow path 424, or both further comprise a heat exchanger 428 located between the sample inlet 416 and the external environment 422.
  • the heat exchanger 428 may be removably attached to a portion of the flow path past the flow control element as shown. Accordingly, the heat exchanger 428, also referred to as a "sample cooler", i.e., a piece of cooled tubing in a bucket of ice water, may be utilized to acquire samples of the inner chamber 402, when the inner chamber is at an elevated temperature.
  • the first flow path 414 is located within a first conduit 430 having a first outlet end 432 equipped with a first valve 434 comprising the first flow control element 418.
  • the valve may be a ball valve, a gate valve, and/or the like.
  • the first valve is a severe service ball valve equipped with a seat flush system 436 to prevent particulate matter, e.g., the ion exchange resin located in inner chamber 402, from inhibiting closing of the valve after a sample is obtained.
  • the second flow path 424 is at least partially located within a second conduit 438 attached at an attachment point 440 to the first conduit 430, and having a second outlet end 442 equipped with a second valve 444 comprising the second flow control element 420.
  • the porous element 426 is located at or proximate to the attachment point 440, at or proximate to the second outlet end 442, or a combination thereof.
  • the porous element comprises a screen, a porous frit, a filter element, or a combination thereof, generally represented as 446.
  • the exclusion size of the element may be varied.
  • the screen or filter element 446 of the porous element 426 may be a 100 mesh screen in a first position, and a 200 mesh screen in a second downstream position, depending on the relative size of the particulate matter (e.g., the purification resin) contained within inner chamber 402.
  • the particulate matter e.g., the purification resin
  • the first open flow path 414 is dimensioned and arranged to allow both liquid 450 and solids 448 from the inner chamber 402 to flow from the sample inlet 416 through the first flow control element 418 in the open position, and into an external environment 422; and the second flow path 424 is dimensioned and arranged to allow the liquid 450 present in the inner chamber 402 to flow from the sample inlet 416 through the porous element 426, through the second flow control element 420 in the open position, and into the external environment 422, while excluding at least a portion of solids or semisolid material 448 present in the inner chamber 402 from flowing through the second flow control element 420.
  • At least a portion 456 of the first flow path 414 is located within a first conduit 430 extending into the inner chamber 402 away from an inner surface 458 of the side 404 through which the sampling port 412 is disposed, such that the sample inlet 416 is located within the inner chamber 402 spaced away from the side 404.
  • the sample inlet 416 is located at the side 404 through which the sampling port 412 is disposed.
  • the inner chamber 402 has an average inner diameter 452 determined orthogonal to the central axis 406 between opposing sides 404 which is less than 50% of an average length 454 of the inner chamber 402 determined parallel to the central axis 406 between the inlet end 408 and the outlet end 406.
  • the first conduit 430 comprises a plurality of sample inlets 416. In embodiments, all of the plurality of sample inlets of a single first conduit 430 are located coplanar with a plane 460 orthogonal to the central axis 406.
  • the sampling ports 412 are arranged longitudinally (along at least a portion of one or more sides parallel to the central axis from the inlet 408 end to the outlet end 410) at essentially equal intervals 462 along at least a portion of the side 404.
  • a process comprise providing a column 400 according to any one or combination of embodiments disclosed herein comprising at least one, preferably a plurality of sampling ports 412 according to any one or combination of embodiments disclosed herein wherein the inner chamber 402 comprises an amount of a purification resin 448 at least partially filling the inner chamber 402.
  • the stream to be purified 464 e.g., an acetic acid stream and/or an intermediate production stream, having one or more impurities at a first concentration is then directed through the column from the inlet end 408 through the inner chamber 402 contacting the purification resin 448 then through the outlet end 410 at a temperature and flow rate sufficient to produce a purified liquid stream 466, e.g., a purified acetic acid stream and/or an intermediate production stream, having an impurity at a second concentration which is less than the first concentration.
  • a purified liquid stream 466 e.g., a purified acetic acid stream and/or an intermediate production stream, having an impurity at a second concentration which is less than the first concentration.
  • the purification resin 448 comprises a macroreticular, strong acid, ion exchange resin wherein at least about 1 percent of the active sites of the resin have been converted to the silver or mercury form; wherein the temperature is at least about 50°C, and wherein the silver or mercury exchanged ion exchange resin is effective to remove at least about 90 percent by weight of Ci-C2o organic iodides in the acetic acid stream.
  • the purification resin 448 is present within the inner chamber 402 in a plurality of bands 468 and 470, a first band 468 located between the inlet end 408 and the second band 470, and the second band 470 located between the first band 468 and the outlet end 410.
  • the purification resin in the first band 468 is the same as the purification resin in the second band 470.
  • the purification resin in the first band 468 is different than the purification resin in the second band 470.
  • the purification resin in the first band 468 is a non-functionalized macroreticular, strong acid, ion exchange resin and the purification resin in the second band 470 comprises a macroreticular, strong acid, ion exchange resin wherein at least about 1 percent of the active sites of the resin have been converted to the silver or mercury form.
  • a process according to one or more embodiments disclosed herein further comprises operating a first flow control element 418 from a closed positon to an open position for a period of time sufficient to obtain a sample comprising liquid 450 and purification resin 448 from a first sampling port and then returning the first flow control element 418 back to a closed position, and/or operating a second flow control element 420 from a closed positon to an open position for a period of time sufficient to obtain a sample comprising liquid 450 from a first sampling port and then returning the second flow control element 420 back to the closed position.
  • the process may further comprise analyzing one or more of the samples to determine one or more concentrations of one or more impurities at the corresponding sampling port.
  • the process may further comprise attaching a heat exchanger to an outlet of the sampling port prior to operating the valve to obtain a sample having a reduced temperature relative to the temperature of the inner chamber.
  • the process may further comprise providing a plurality of the columns wherein an outlet end of a first column is in direct fluid communication with an inlet end of a second column.
  • samples obtained from the sampling ports may include a sample of the purification resin present in the column, a liquid sample of the acetic acid stream present in the column, or both.
  • the arrangement of the sampling ports allows for samples to be obtained at discrete points through the resin bed.
  • a sampling port may also be located proximate to the final purified acetic acid stream produced by the column.
  • Liquid samples may be amenable to gas chromatographic (GC) analysis, high pressure liquid chromatography (HPLC) analysis, which is to be understood to include normal phase, reverse phase, ion exclusion, ion pair, size exclusion, ion exchange, and ion chromatographic techniques readily understood by one having minimal skill in the art. Any form of suitable detector may be employed.
  • GC gas chromatographic
  • HPLC high pressure liquid chromatography
  • resin samples may be extracted and/or digested to allow for any of the various chromatographic techniques, and/or may be analyzed via wet chemical techniques, atomic absorption analysis, which may include inductively coupled plasma (ICP) analysis, mass spectral analysis, ICP-MS and/or the like.
  • the resin samples may be analyzed using X-ray fluorescence techniques, as are readily understood by one of minimal skill in the art.
  • the samples may be analyzed for halogens, or iodide (I) and/or for various transition metals from Groups 3 to 12, or corrosion metals typical of acetic acid production such as Fe, Cr, and/or Ni, and may also be analyzed for the presence of the metal or moiety with which the active sites of the resin were converted, which may include silver and/or mercury.
  • halogens or iodide (I) and/or for various transition metals from Groups 3 to 12, or corrosion metals typical of acetic acid production such as Fe, Cr, and/or Ni
  • a combination of utilizing the sampling ports and analysis may be used to control column operation, which may include monitoring the ability of the column to remove impurities and diverting flow around the column prior to the impurity retention or removal characteristics of the column being exhausted.
  • an impurity concentration of a sample may be compared a previously determined impurity concentration value which indicates whether or not the purification resin is functioning or has become exhausted. This information may be combined with the location of the sample port such that the impurity concentration of the sample indicates exhaustion of the purification resin at a point in the column corresponding to the location of the sample port from which the sample was obtained.
  • a resin is exhausted when it is in longer capable of purifying the acetic acid to an acceptable level.
  • a purification resin is considered "exhausted" when the acetic acid which has contacted this resin has an iodide concentration above 100 ppb by weight, a Fe, Cr, and/or Ni concentration above 500 ppb by weight, or a combination thereof.
  • a resin sample containing greater than or equal to about 10 weight percent of the impurity is also considered to be exhausted for purposes herein.
  • these levels merely reflect current requirements for product acetic acid, and any such levels may be used.
  • the levels used and the impurities analyzed for (determined) may be different than iodide and corrosion metals, depending of the stream in which the column is placed.
  • an indication of an exhausted column may result in flow through the particular column being stopped and/or diverted though a suitable column.
  • the progression of the impurities through the column may be used to determine the rate at which the column is becoming exhausted, and thus may be used to predict the life expectancy or otherwise control the use of the column in the process
  • a determination of exhausted resin proximate to the end of the column, but not yet in the final purified acetic acid may be utilized to stop or otherwise divert flow around the column to allow for resin replacement and/or resin regeneration.
  • the resin may be regenerated.
  • the regeneration of the exhausted resin comprises removing at least a portion of the exhausted resin from the column and refilling at least a portion of the column with active purification resin.
  • at least a portion of the active resin used to refill the column comprises previously exhausted resin which has been regenerated into active purification resin.
  • at least a portion of the exhausted resin is regenerated into the active purification resin within the column, also referred to as in-situ regeneration. Regeneration of the resin depends on the type of resin and the impurities being removed. Regeneration processes may include contacting the resin with suitable solvents, reagents, and/or the like.
  • a method or process 500 comprises the steps of providing a column according to any one or combination of embodiments disclosed herein comprising an inner chamber 502.
  • the process may further include a column comprising one or more sample ports arranged between the column inlet and the column outlet, at least one sample port comprising a liquid sample port, a solid sample port, or both, and opening at least one sample port 505.
  • the method or process includes directing an amount of purification resin into the inner chamber sufficient to fill a portion of the inner chamber 504.
  • filling the column comprises opening at least one sample port.
  • the sample ports may be used to wash the resin, to remove vapor from the resin, to purge the inner chamber with inert gas during charging of the resin, and/or the like.
  • the resin may be place into the column in a dry or wet form by either manually transferring the resin into the top of the column or pumping a slurry into the column.
  • the resin may be supplied as a slurry in a container, such as liquid tote, a tank truck, or tanker rail car, and pneumatically transferred into the column.
  • a bottom outlet of a container comprising a slurry comprising the purification resin is put into fluid communication with the inner chamber.
  • a pressure is then applied to a headspace of the container in an amount sufficient to pneumatically transfer at least a portion of the slurry from the container into the inner chamber 506.
  • the resin may then be backwashed 510 with a wash fluid, typically water or another solvent to remove fines, foreign matter, and artifacts of production.
  • a wash fluid typically water or another solvent to remove fines, foreign matter, and artifacts of production.
  • the wash may persist for at least 60 minutes 518. This backwash may be sent to waste or otherwise recycled as may be appropriate. Washing times may be an hour or more, at relatively high flow rates to ensure even dispersion of the resin within the column and to prevent pockets in the resin.
  • the wash may then be removed from the resin by applying pressure to the top of the column 512 using nitrogen or the like, and maintaining the pressure until the gas blows through the column outlet, indicating that essentially all of the wash has been removed.
  • the resin may then once again be back flushed only this time with acetic acid 514.
  • the acid back flush is conducted at a relatively slow rate, with a flow rate of acid into the base of the column of less than 0.05 or less than 0.04 bed volumes per minute 516.
  • the back flush may be conducted until all of the vapor present within the column has been displaced by liquid.
  • at least some of the vapor is removed through one or more open sample ports.
  • only a portion of the inner chamber is initially filled with resin to allow for swelling of the resin, which in embodiments may be as much as 40% or more when the resin is exchanged from water to acetic acid.
  • the column may be put into use by directing the flow of acetic acid having the first impurity concentration from the inlet end to the outlet end at a purification temperature and flow rate sufficient to produce a purified acetic acid stream having a second impurity concentration at the outlet end which is less than the first impurity concentration 520.
  • a) providing a treatment device column comprising an inner chamber comprising an active purification resin located between a column inlet and a column outlet, the column further comprising one or more sample ports arranged between the column inlet and the column outlet, at least one sample port comprising a liquid sample port, a solid sample port, or both;
  • exhausted resin comprises removing at least a portion of the exhausted resin from the column and refilling at least a portion of the column with active purification resin.
  • a treatment device column comprising an inner chamber bound by a plurality of sides radially arranged about a central axis and having an inlet end in fluid communication with, and longitudinally separated from, an outlet end through the inner chamber;
  • directing the purification resin into the inner chamber comprises providing fluid communication between the inner chamber and a bottom outlet of a container comprising a slurry comprising the purification resin; and applying a pressure to a headspace of the container in an amount sufficient to pneumatically transfer at least a portion of the slurry from the container into the inner chamber.
  • impurity comprises iodine, chromium, nickel, iron, or a combination thereof; wherein the purification resin comprises a macroreticular, strong acid, ion exchange resin having at least about 1 percent active sites in a silver or mercury form;
  • the temperature is at least about 50°C, or a combination thereof.
  • impurity comprises iodine, chromium, nickel, iron, or a combination thereof; wherein the purification resin comprises a macroreticular, strong acid, ion exchange resin having at least about 1 percent active sites in a silver or mercury form; wherein the temperature is at least about 50° C, or a combination thereof.
  • E27 A process comprising carbonylating at least one member selected from the group consisting of methanol, dimethyl ether, and methyl acetate in the presence of 0.1 to less than 14 wt.% water, a rhodium catalyst, methyl iodide and lithium iodide, to form a reaction medium comprising acetic acid in a reactor;
  • reaction medium comprising acetic acid in a reactor; separating the reaction medium into a liquid recycle stream and a vapor product stream;
  • a second purification resin comprising a metal-exchanged ion exchange resin having acid cation exchange sites within a second treatment device to produce a purified acetic acid stream, the first treatment device, the second treatment device, or both individually comprising at least one sampling port disposed through a side of the treatment device;
  • the process according to embodiment E27 or E28 further comprising comparing the impurity concentration of at least one sample to a previously determined impurity concentration value, and determining if the impurity concentration of the sample indicates exhaustion of the purification resin at a point in the treatment device corresponding to the location of the sample port from which the sample was obtained.
  • E30 The process according to any one of embodiments E27 to E29, further comprising stopping the flow of acetic acid through the treatment device prior to exhaustion of essentially all of the active purification resin present in the treatment device, regenerating at least a portion of the exhausted resin according to any one of embodiments E16 to E26, and resuming flow of the acetic acid stream through the treatment device to produce the purified acetic acid stream.
  • E36 The process according to any one of embodiments E27 to E35,wherein the intermediate acetic acid product is contacted with the metal-exchanged ion exchange resin at a temperature from 50°C to 85°C; or a combination thereof.
  • E37 The process according to any one of embodiments E27 to E36, wherein the intermediate acetic acid product has a lithium ion concentration of less than 50 ppb.
  • concentration in the reaction medium is controlled from 0.1 to 5 wt , based on the total amount of reaction medium present.
  • lithium compound selected from the group consisting of lithium acetate, lithium carboxylates, lithium carbonates, lithium hydroxide, and mixtures thereof into the reactor to maintain the concentration of lithium acetate from 0.3 to 0.7 wt in the reaction medium.
  • concentration in the methanol feed into the reactor is less than 150 wppm; or a

Landscapes

  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Engineering & Computer Science (AREA)
  • Oil, Petroleum & Natural Gas (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Crystallography & Structural Chemistry (AREA)
  • Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
EP15781530.9A 2015-01-30 2015-10-02 Processes for producing acetic acid Pending EP3250542A1 (en)

Applications Claiming Priority (4)

Application Number Priority Date Filing Date Title
US201562109765P 2015-01-30 2015-01-30
US201562141490P 2015-04-01 2015-04-01
US14/694,913 US9540302B2 (en) 2015-04-01 2015-04-23 Processes for producing acetic acid
PCT/US2015/053884 WO2016122728A1 (en) 2015-01-30 2015-10-02 Processes for producing acetic acid

Publications (1)

Publication Number Publication Date
EP3250542A1 true EP3250542A1 (en) 2017-12-06

Family

ID=54330071

Family Applications (1)

Application Number Title Priority Date Filing Date
EP15781530.9A Pending EP3250542A1 (en) 2015-01-30 2015-10-02 Processes for producing acetic acid

Country Status (8)

Country Link
EP (1) EP3250542A1 (es)
KR (1) KR102493740B1 (es)
CN (1) CN107207392B (es)
MX (1) MX2017009867A (es)
MY (1) MY181742A (es)
SA (1) SA517381989B1 (es)
SG (1) SG11201706008YA (es)
WO (1) WO2016122728A1 (es)

Families Citing this family (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US10550058B2 (en) 2017-03-08 2020-02-04 Daicel Corporation Method for producing acetic acid
ES2817406T3 (es) * 2017-03-08 2021-04-07 Daicel Corp Método para la producción de ácido acético
US10457622B2 (en) 2017-03-08 2019-10-29 Daicel Corporation Method for producing acetic acid
US10428005B2 (en) 2017-03-22 2019-10-01 Daicel Corporation Method for producing acetic acid
US10584087B2 (en) * 2018-03-23 2020-03-10 Lyondellbasell Acetyls, Llc Removal of permanganate reducing compounds from intermediate GAA process streams
WO2019183541A1 (en) * 2018-03-23 2019-09-26 Lyondellbasell Acetyls, Llc Improved method for purification of gaa

Family Cites Families (66)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US783871A (en) 1904-11-19 1905-02-28 Edward Lawson Tension device.
US3769329A (en) 1970-03-12 1973-10-30 Monsanto Co Production of carboxylic acids and esters
BE791577A (fr) 1971-11-19 1973-05-17 Monsanto Co Purification de courants d'acide carboxylique
US4039395A (en) 1975-08-11 1977-08-02 Monsanto Company Purification of acetic acid
US4139688A (en) 1977-06-24 1979-02-13 Gaf Corporation Preparation of insoluble polyvinylpyrrolidone
US4255591A (en) 1978-11-20 1981-03-10 Monsanto Company Carbonylation process
US5144068A (en) 1984-05-03 1992-09-01 Hoechst Celanese Corporation Methanol carbonylation process
US5001259A (en) 1984-05-03 1991-03-19 Hoechst Celanese Corporation Methanol carbonylation process
US5026908A (en) 1984-05-03 1991-06-25 Hoechst Celanese Corporation Methanol carbonylation process
CA1228867A (en) 1984-05-03 1987-11-03 G. Paull Torrence Methanol carbonylation process
US4615806B1 (en) 1985-03-07 1994-05-03 Hoechst Co American Removal of iodide compounds from non-aqueous organic media
DE3532747A1 (de) 1985-09-13 1987-03-26 Basf Ag Verfahren zur herstellung von polyvinylpyrrolidon
US5139981A (en) 1987-06-24 1992-08-18 Union Carbide Chemicals & Plastics Technology Corporation Process for preparing silver(I)-exchanged resins
US5237097A (en) 1990-02-09 1993-08-17 Quantum Chemical Corporation Catalytic carbonylation process
GB9023634D0 (en) 1990-10-31 1990-12-12 British Petroleum Co Plc Process for purifying acetic acid and/or acetic anhydride
US5220058A (en) 1991-09-30 1993-06-15 Union Carbide Chemicals & Plastics Technology Corporation Iodide removal process
GB9120902D0 (en) 1991-10-02 1991-11-13 Bp Chem Int Ltd Purification process
GB9122168D0 (en) * 1991-10-18 1991-11-27 Bp Chem Int Ltd Process
US5334755A (en) 1992-04-24 1994-08-02 Chiyoda Corporation Process for the production of acetic acid from methanol and carbon monoxide using supported rhodium catalyst
GB9211671D0 (en) 1992-06-02 1992-07-15 Bp Chem Int Ltd Process
US5281359A (en) 1992-08-31 1994-01-25 Hoechst Celanese Corporation Polymeric carbonylation catalyst system
US5286826A (en) 1993-03-05 1994-02-15 Isp Investments Inc. Process for making highly crosslinked polyvinylpyrrolidone having a low swell volume
JP3377555B2 (ja) 1993-05-31 2003-02-17 ダイセル化学工業株式会社 カルボニル化反応生成物に含有されるヨウ素化合物の除去方法
DE69500905T2 (de) 1994-05-31 1998-02-12 Eastman Chem Co Verfahren zur Entfernung von Jod enthaltenden Verbindungen aus Essigsäure
JP3332594B2 (ja) 1994-08-12 2002-10-07 ダイセル化学工業株式会社 酢酸の精製方法
DE19519197A1 (de) 1995-05-24 1996-11-28 Linde Ag Verfahren zum Rückgewinnen von Kohlenmonoxid aus einem wenigstens Kohlenmonoxid, Stickstoff und Wasserstoff enthaltenden Purgegas der Essigsäuresynthese
CN1092179C (zh) 1995-10-27 2002-10-09 赫希斯特人造丝公司 除去腐蚀金属以改善羰基化催化剂溶液生产率的方法
JP3281258B2 (ja) * 1996-04-26 2002-05-13 ダイセル化学工業株式会社 有機媒質中に含まれるヨウ素化合物を除去する際の運転方法
US6339171B1 (en) 1996-10-18 2002-01-15 Celanese International Corporation Removal or reduction of permanganate reducing compounds and alkyl iodides from a carbonylation process stream
IN192600B (es) 1996-10-18 2004-05-08 Hoechst Celanese Corp
US5831120A (en) 1996-11-19 1998-11-03 Watson; Derrick John Process for the production of acetic acid
US5962735A (en) 1998-03-06 1999-10-05 Uop Llc Method for treating an organic liquid contaminated with an iodide compound
GB9819079D0 (en) 1998-09-03 1998-10-28 Bp Chem Int Ltd Carbonylation process
US6225498B1 (en) 2000-03-24 2001-05-01 Celanese International Corporation Method of removing organic iodides from organic media
US6627770B1 (en) 2000-08-24 2003-09-30 Celanese International Corporation Method and apparatus for sequesting entrained and volatile catalyst species in a carbonylation process
CN1117628C (zh) 2000-10-24 2003-08-13 中国科学院化学研究所 均相甲醇羰基化反应双金属催化剂及其制法
US6657078B2 (en) * 2001-02-07 2003-12-02 Celanese International Corporation Low energy carbonylation process
US7671193B2 (en) 2001-03-14 2010-03-02 Daicel Chemical Industries, Ltd. Method for adjusting the degree of substitution with acetyl group of cellulose acetate
JP2004131389A (ja) 2002-10-08 2004-04-30 Daicel Chem Ind Ltd カルボン酸の製造方法及び製造システム
CN1270825C (zh) 2004-01-09 2006-08-23 中国科学院化学研究所 一种正负离子型双金属催化剂及制备方法和应用
US7223886B2 (en) 2004-03-02 2007-05-29 Celanese International Corporation Removal of permanganate reducing compounds from methanol carbonylation process stream
US7208624B2 (en) 2004-03-02 2007-04-24 Celanese International Corporation Process for producing acetic acid
US7223883B2 (en) 2004-03-02 2007-05-29 Celanese International Corporation Removal of permanganate reducing compounds from methanol carbonylation process stream
US7271293B2 (en) 2004-03-02 2007-09-18 Celanese International Corporation Control method for process of removing permanganate reducing compounds from methanol carbonylation process
JP5075336B2 (ja) 2004-12-20 2012-11-21 株式会社ダイセル 酢酸の製造方法
US7855306B2 (en) 2005-04-28 2010-12-21 Celanese International Corporation Process for the production of acetic acid
US7678940B2 (en) 2005-07-14 2010-03-16 Daicel Chemical Industries, Ltd. Process for producing carboxylic acid
CN100411738C (zh) 2006-04-10 2008-08-20 中国科学院化学研究所 有机金属锂盐为配体的铑催化剂
JP4995522B2 (ja) 2006-09-25 2012-08-08 千代田化工建設株式会社 有機酸からのヨウ素化合物除去方法
US7884237B2 (en) 2008-11-07 2011-02-08 Celanese International Corp. Methanol carbonylation with improved aldehyde removal
CN102804245A (zh) 2009-06-15 2012-11-28 松下电器产业株式会社 等离子显示面板的驱动方法和等离子显示装置
JP5461099B2 (ja) 2009-08-05 2014-04-02 株式会社ダイセル 新規な露出結晶面を有するルチル型二酸化チタンナノ粒子とその製造方法
US20130026458A1 (en) 2010-04-16 2013-01-31 Daicel Corporation Crosslinkable composition
CN105111067B (zh) 2010-05-18 2018-02-06 国际人造丝公司 通过除去高锰酸盐还原化合物纯化乙酸物流的方法
KR101747484B1 (ko) 2010-07-26 2017-06-14 주식회사 다이셀 아세트산의 제조 방법
CN102399140B (zh) * 2010-09-17 2015-04-15 联仕(上海)电子化学材料有限公司 一种超纯电子级醋酸的生产方法
US8394988B2 (en) 2010-09-28 2013-03-12 Celanese International Corporation Production of acetic acid with high conversion rate
EP2628720B1 (en) 2010-10-06 2018-11-07 Daicel Corporation Acetic acid production method
US9056825B2 (en) 2010-10-13 2015-06-16 Celanese International Corporation Process for recovering halogen promoters and removing permanganate reducing compounds
EP2629091B1 (en) 2010-10-13 2019-03-20 Daicel Corporation Separating agent for chromatography and method for the production thereof
JP5914358B2 (ja) 2010-12-15 2016-05-11 株式会社ダイセル 酢酸の製造方法
CN103370300B (zh) 2010-12-15 2016-07-06 株式会社大赛璐 乙酸的制备方法
CN103370297B (zh) 2010-12-15 2015-10-07 株式会社大赛璐 乙酸的制备方法
MY162807A (en) 2010-12-24 2017-07-14 Daicel Corp Acetic acid production method
TWI547477B (zh) 2012-03-14 2016-09-01 大賽璐股份有限公司 醋酸之製造方法
AR094541A1 (es) * 2013-01-25 2015-08-12 Daicel Corp Procedimiento para producir ácido carboxílico

Non-Patent Citations (2)

* Cited by examiner, † Cited by third party
Title
None *
See also references of WO2016122728A1 *

Also Published As

Publication number Publication date
SG11201706008YA (en) 2017-08-30
KR102493740B1 (ko) 2023-01-30
CN107207392A (zh) 2017-09-26
KR20170110656A (ko) 2017-10-11
MY181742A (en) 2021-01-06
MX2017009867A (es) 2017-11-15
WO2016122728A1 (en) 2016-08-04
SA517381989B1 (ar) 2021-11-02
CN107207392B (zh) 2021-06-08

Similar Documents

Publication Publication Date Title
WO2016122728A1 (en) Processes for producing acetic acid
JP6034478B2 (ja) 酢酸の製造方法
US9487464B2 (en) Processes for producing acetic acid
US9540303B2 (en) Processes for producing acetic acid
US9561994B2 (en) Processes for producing acetic acid
US10899696B2 (en) Processes for purifying acetic acid and hydrating anhydride
EP3277654B1 (en) Processes for producing acetic acid
EP3250545B1 (en) Processes for producing acetic acid
EP3374342B1 (en) Processes for producing acetic acid
JP6034477B2 (ja) 酢酸の製造方法
EP3218105B1 (en) Processes for improving acetic acid yield by removing iron
CA2566795A1 (en) Process for the removal of catalytic metals and promoter metals from carbonylation process streams

Legal Events

Date Code Title Description
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: THE INTERNATIONAL PUBLICATION HAS BEEN MADE

PUAI Public reference made under article 153(3) epc to a published international application that has entered the european phase

Free format text: ORIGINAL CODE: 0009012

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: REQUEST FOR EXAMINATION WAS MADE

17P Request for examination filed

Effective date: 20170830

AK Designated contracting states

Kind code of ref document: A1

Designated state(s): AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR

AX Request for extension of the european patent

Extension state: BA ME

DAV Request for validation of the european patent (deleted)
DAX Request for extension of the european patent (deleted)
STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

17Q First examination report despatched

Effective date: 20200327

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS

STAA Information on the status of an ep patent application or granted ep patent

Free format text: STATUS: EXAMINATION IS IN PROGRESS