JP2016164137A - Processes for producing acetic acid - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide processes for controlling and monitoring purification systems to remove various impurities present in producing acetic acid.SOLUTION: A carbonylation process for producing acetic acid includes: separating a vapor product stream 113 from a carbonylation reactor 104 to produce a crude acid product comprising acetic acid comprising lithium cations and contacting the crude acetic acid product with a cationic exchanger in the acid form within a treatment device 200 having a plurality of sampling ports so as to produce an intermediate acid product 146; and then contacting the intermediate acetic acid product 146 with a metal-exchanged ion exchange resin having acid cation exchange sites to produce a purified acetic acid.SELECTED DRAWING: Figure 1

Description

  [0001] This application claims priority to US provisional application 62/109765, filed January 30, 2015, and claims priority benefit to US provisional application 62/141490, filed April 1, 2015. Which is a continuation-in-part of US application 14/694913 filed April 23, 2015, each of which is fully incorporated herein by reference.

  [0002] The production of acetic acid by carbonylation involves the continuous reaction of methanol and carbon monoxide in the reactor in the presence of a catalyst. The reaction mixture present in the reactor may be a Group 9 metal and includes a transition metal, which may be iridium and / or rhodium, one or more solvents, water, various stabilizers, cocatalysts, promoters. An agent or the like can be further included. Reaction mixtures known in the art can include acetic acid, methyl acetate, methyl iodide, hydrogen iodide, hydrogen iodide promoter, and the like.

  [0003] There are complex networks of interdependent equilibria involving liquid acetic acid reactants, including those directed to the formation of acetic acid and various similarly produced in the reactor. Included are those directed to the formation of impurities. Impurities that may be present in acetic acid include permanganate reducing compounds (PRC) such as acetaldehyde. Thus, the acetic acid process disclosed in the art further includes various purification processes and control schemes that minimize the formation of impurities and / or remove generated impurities from the process or convert them to product acetic acid. there is a possibility.

  [0004] Various impurities present in the production of acetic acid are difficult to remove. There is a need to control and monitor the purification system in various forms of acetic acid production processes.

  [0005] In some embodiments, the method includes, in the reactor, at least one component selected from the group consisting of methanol, dimethyl ether, and methyl acetate in an amount of 0.1 to less than 14% by weight. Carbonylation in the presence of water, rhodium catalyst, methyl iodide, and lithium iodide to form a reaction medium containing acetic acid; separating the reaction medium into a liquid recycle stream and a vapor product stream; Separating the vapor product stream in no more than two distillation columns to produce a crude acid product comprising acetic acid containing lithium cations; in the first processing unit, the crude acetic acid product is cation exchanged in acid form The intermediate acid product is contacted with a first purified resin comprising a body; and in the second processor, the intermediate acetic acid product is converted to a metal exchange having an acid cation exchange site. In contact with a second purifying resin comprising a purified ion exchange resin to produce a purified acetic acid stream, wherein the first processing unit, the second processing unit, or both are individually connected to the processing unit. Including at least one sampling port disposed through the side; through the corresponding sampling port, a first purified resin, a second purified resin, a liquid sample of acetic acid stream present in the processing apparatus, or these Obtaining a sample of the combination; and determining the concentration of impurities in the at least one sample.

  [0006] This summary is provided to introduce a selection of concepts that are further described below in the detailed description. This summary is not intended to identify key features or essential features of the claimed subject matter, but is also intended to be used as an aid in limiting the scope of the claimed subject matter. Not done.

[0007] FIG. 1 is a schematic diagram of a method for producing acetic acid according to one embodiment. [0008] FIG. 2 is a schematic diagram of a series of processing devices according to one aspect. [0009] FIG. 3 is a cross-sectional view of a processing apparatus according to one aspect. [0010] FIG. 4 is a cross-sectional view of a sampling device according to one aspect. [0011] FIG. 5 is a block diagram illustrating a process of filling a processor column with resin according to some embodiments.

  [0012] First, in the development of any such actual aspect, the developer's specifics, such as compatibility with system-related and business-related restrictions that vary from one implementation to the other. It should be noted that many implementation-specific decisions must be made to achieve the goal. Further, it will be appreciated that such development efforts can be complex and time consuming, but will still be a routine task for those skilled in the art having the benefit of this disclosure. Further, as will be apparent to those skilled in the art, the methods disclosed herein may also include components other than those listed or specifically mentioned.

  [0013] In the general description and this detailed description, each numerical value is read as once modified by the term "about" (unless it has already clearly been so modified) and then others in context. Should be read again as if not so modified unless otherwise indicated. Also, in the general description and this detailed description, it is intended that a concentration range listed or described as useful, preferred, etc. should be considered as indicating any and all concentrations within that range, including endpoints. Should be understood. For example, “range 1-10” should be read as indicating any and all possible numbers along a continuum between about 1 and about 10. Thus, if specific data points within this range are clearly identified or only related to a few specific data points, or data points within this range are not clearly identified or few We recognize and understand that any and all data points within this range should have been identified, even if not only with specific data points, and we are within this range. It should be understood that he had knowledge of the full scope and all points.

[0014] Throughout the specification, including the claims, the following terms have the indicated meanings unless otherwise indicated.
[0015] As used in the specification and claims, "near" encompasses "in". The terms and / or refer to both the inclusive “and” case and the exclusive “or” case, and are used herein for brevity. For example, a mixture comprising acetic acid and / or methyl acetate may contain acetic acid alone, methyl acetate alone, or both acetic acid and methyl acetate.

  [0016] New numbering schemes for symbols representing elements and periodic table groups used herein are used consistent with those disclosed in Chemical and Engineering News, 63 (5), 27 (1985). It is what All molecular weights are weight average unless otherwise indicated.

  [0017] All percentages are expressed as weight percent (wt%) based on the total weight of the particular composition or stream present, unless otherwise indicated. Unless otherwise indicated, the room temperature is 25 ° C. and the atmospheric pressure is 101.325 kPa.

  [0018] For purposes of the present invention, the percent of active sites replaced in the resin is based on total exchange capacity and is milliequivalents / gram (meq / g). For example, in a cation ion exchange resin having a cation exchange capacity of 2 meq / g, substitution of 2 meq / g with silver ions constitutes that 100% of the active site is substituted with silver, and substitution of 1 meq / g is It constitutes that 50% of the active sites are replaced.

[0019] For purposes in the present invention,
Acetic acid may be abbreviated as “AcOH”;
Methyl acetate may be abbreviated as “MeAc”;
Methyl iodide may be abbreviated as “MeI”; and carbon monoxide may be abbreviated as “CO].

  [0020] A permanganate reducing compound (PRC) refers to an oxidizable compound that provides an indication of failure of the permanganate salt test, as will be readily understood by those skilled in the art ("A New System For Automatic Measurement of Permanganate Time ", Laboratory Automation and Information Management, 34, 1999, 57-67). Examples of permanganate reducing compounds (PRC) include acetaldehyde, acetone, methyl ethyl ketone, butyraldehyde, crotonaldehyde, 2-ethylcrotonaldehyde, 2-ethylbutyraldehyde, and their aldol condensation products. .

  [0021] For purposes in the present invention, the "top stream" of a distillation column refers to the lowest boiling condensable fraction that is discharged at the top of the distillation column or at a location adjacent to the top. Further, the distillation column residue refers to the highest boiling fraction discharged from or near the bottom of the distillation column. Residue can be recovered from directly above the bottom outlet of the distillation column, for example where the bottom of the column is unusable tar, solid waste, or small amounts, as will be readily understood by those skilled in the art. It is a flow. Furthermore, the top stream can be recovered just below the top outlet of the distillation column, for example, where the fraction with the lowest boiling point is a non-condensable stream as will be readily understood by those skilled in the art. Or it represents a slight flow.

  [0022] The average residence time in the column of the column feed used in the present invention is the value obtained by dividing the total flow rate supplied to the column by the total amount of unoccupied volume present in the column, unless otherwise indicated. Point to.

  [0023] For purposes of the present invention, a processing vessel (sometimes referred to as a column) has an inlet and an outlet. The inside of the column (also referred to as an internal chamber in the present invention) is suitable for filling the purified resin. The terms processor and column are used interchangeably herein unless otherwise indicated. For the purposes of the present invention, columns other than processing equipment and distillation columns are used interchangeably.

  [0024] Mass flow rate as used herein refers to kg / hr unless otherwise indicated and can be determined directly or calculated from volumetric measurements. If the total mass flow rate or concentration of a component is conditioned to be present, “even if present” means that this component is detected by a suitable analytical method, as will be readily understood by those skilled in the art. It should be understood that there may be more or less in the flow than the limit.

  [0025] As used herein, those skilled in the art will readily understand when a flow mass flow rate is "controlled" to either a specific flow rate or a flow rate proportional to the mass flow rate of another flow. As such, such control may include changing the flow of a particular process flow directly or controlling the mass flow of a particular flow by changing the flow that directly affects the mass flow of the subject flow. Should be understood. All such ratios are expressed as weight / weight of mass unless otherwise indicated.

  [0026] The carbonylatable reactant used in the present invention is any material that reacts with carbon monoxide under reaction conditions to produce acetic acid or the desired product. Examples of the carbonylatable reactant include methanol, methyl acetate, dimethyl ether, methyl formate and the like.

[0027] The low water carbonylation process used in the present invention is defined as having a limited concentration of water in the carbonylation reactor of about 14 wt% or less.
[0028] As used in the present invention, when at least part of a stream is recycled or returned to other parts of the process, "part" refers to a part of the total mass flow rate of the stream. Should be understood. This stream can be mixed (i.e. indirectly recycled) with other streams, and all components originally present in the stream are present after mixing.

  [0029] In contrast, a flow “derived from” another flow may include the entire flow, or less than all of the individual components initially present in the flow. there is a possibility. Thus, a stream “derived from” a particular stream can include a stream that has been subjected to further processing or purification prior to disposal. For example, a stream distilled before recirculation is derived from the original stream.

  [0030] Unless otherwise indicated, as used herein, a restriction based on a comparison of an effect observed in the presence of one component to an effect observed in the absence of the same component is It relates to comparisons performed under substantially the same conditions (eg, substantially the same composition, substantially the same temperature, time, and other conditions) except for the presence or absence of a specified component.

  [0031] Impurities present in acetic acid include various iodine-containing species. Examples include alkyl iodides having 1 to about 20 carbon atoms. Higher molecular weight alkyl iodides having more than about 6 carbons may be present in the final product at levels of several ppb. These impurities are problematic for various end uses of acetic acid and need to be removed according to various purification standard techniques. Other impurities include various aldehydes and corrosive metals. These contaminants can be removed by contacting acetic acid with a suitable purification resin at temperatures above about 50 ° C. (see US Pat. No. 6,657,078). However, the use of such purified resins requires monitoring both the final product and the resin itself to prevent impurities from “breaking through” the purified resin bed during manufacture.

  [0032] Although a sample of the final product is readily available, a sample of purified resin used in such a purification process is almost impossible to obtain while the purification system is in operation. Furthermore, it is uneconomical and often unreliable to stop such a purification system and obtain a resin sample. However, the sampling device according to one or more aspects of the present invention allows both liquid samples and solid purified resin samples to be obtained and analyzed at various locations along the resin bed. The ability to obtain these samples allows for improved monitoring and control over the process. In addition, these sampling ports make it possible to predict when the resin will be depleted before excessive amounts of impurities are present in the final product.

  [0033] In some embodiments, the method includes an internal chamber containing an active purification resin disposed between the column inlet and the column outlet, wherein the one or more are arranged between the column inlet and the column outlet. And at least one sampling port provides a column including a liquid sampling port, a solid sampling port, or both; and an acetic acid stream having a first concentration of impurities, if present, Flowing a purified acetic acid stream having a second concentration of impurities lower than the first concentration through the column at a temperature and flow rate sufficient to produce at the column outlet. Accordingly, acetic acid is contacted with the purification resin in the column to remove impurities and purify acetic acid. In some embodiments, the method further comprises opening at least one sampling port before or simultaneously with flowing the acetic acid stream through the column. In some embodiments, the impurities include iodine, chromium, nickel, iron, or combinations thereof. In some embodiments, the iodide may be an alkyl iodide. In some embodiments, the purified resin comprises a macroreticular strong acid ion exchange resin having active sites in the form of at least about 1% silver or mercury and / or the temperature is at least about 50 ° C.

  [0034] In some embodiments, opening at least one sampling port includes purifying a sample of purified resin through at least one solid sampling port, liquid in an acetic acid stream present in the column through at least one liquid sampling port. Obtaining a sample, or combinations thereof, can be included, and the method further includes determining a concentration of impurities in the at least one sample.

  [0035] In some embodiments, the concentration of the one or more impurities is gas chromatography, high pressure liquid chromatography, atomic absorption, inductively coupled plasma spectroscopy, mass spectroscopy, X-ray fluorescence spectroscopy, or a combination thereof Find using.

  [0036] In some embodiments, the impurity concentration of one or more samples is compared to the previously determined impurity concentration value, and the impurity concentration corresponds to the position in the column corresponding to the position of the sampling port from which the sample was obtained. It is determined whether or not the consumption of the purified resin is indicated. In some embodiments, the method can further include stopping the flow of acetic acid through the column. In some embodiments, the flow of acetic acid is stopped before substantially all of the active purification resin present in the column is depleted, so that the concentration of impurities in the product acetic acid allows acetic acid to be used for certain end uses. Do not be inappropriate.

  [0037] In some embodiments, acetic acid is flowed through the second column while providing a second column similar to the first column and stopping flow through the first column. This can be purified in the second column.

  [0038] In some embodiments, at least a portion of the depleted resin prior to resuming the flow of acetic acid stream through the column to produce a purified acetic acid stream while stopping flow to the column. Play. In some embodiments, regeneration of the spent resin includes removing at least a portion of the spent resin from the column and refilling at least a portion of the column with the active purified resin. In some embodiments, at least a portion of the active resin used to repack the column includes previously depleted resin regenerated to an active purified resin. In some embodiments, at least a portion of the depleted resin is regenerated into active purified resin within the column.

  [0039] In some embodiments, the method includes (a) coupled by a plurality of sides arranged radially about a central axis and in fluid communication with the outlet end through the internal chamber. Providing a column including an internal chamber having an inlet end longitudinally spaced therefrom; (b) delivering a sufficient amount of purified resin into the internal chamber to fill a portion of the internal chamber; ) Flowing an aqueous wash fluid from the outlet end through the internal chamber to the inlet end at a flow rate and for a time sufficient to wash and / or remove particulates from the purified resin; and (d) acetic acid having a first concentration of impurities. Flowing a stream through the column at a temperature and flow rate sufficient to produce a purified acetic acid stream having a second concentration of impurities, if any, less than the first concentration at the column outlet; Including.

  [0040] In some embodiments, the column includes one or more sampling ports arranged between the column inlet and the column outlet, wherein the at least one sampling port is a liquid sampling port, a solid sampling port, or both And the method further includes opening at least one sampling port. In some embodiments, the aqueous cleaning fluid is flowed for at least 60 minutes.

  [0041] In some embodiments, after step (c) of flowing the aqueous wash fluid through the column, a predetermined amount of inert gas is sent into the column inlet to remove a portion of the wash fluid. In some embodiments, a backwash stream of acetic acid can then be flowed through the column (from the outlet to the inlet) at a flow rate and time sufficient to remove substantially all of the vapor from the internal chamber. In some aspects, the removal of vapor may include opening one or more sampling ports. In some embodiments, the acetic acid backwash flow rate is about 0.05 bed volume / min or less, and the time is about 30 minutes or less.

  [0042] In some embodiments, the purified resin provides fluid communication between the inner chamber and the bottom outlet of the container containing the slurry containing the purified resin, and then at least a portion of the slurry is removed from the container into the inner chamber. Air is fed pneumatically into the internal chamber of the column by applying a sufficient amount of pressure to the vessel headspace to pneumatically transfer to the column.

  [0043] In some embodiments, prior to filling the column with purified resin, the internal chamber of the column and / or the headspace of the vessel is purged with an inert gas, such as nitrogen, to remove oxygen from the space. (I.e., the space contains less than 1 wt% oxygen).

  [0044] In some embodiments, the method includes, in the reactor, at least one component selected from the group consisting of methanol, dimethyl ether, and methyl acetate in an amount of 0.1 to less than 14% by weight. Carbonylation in the presence of water, rhodium catalyst, methyl iodide, and lithium iodide to form a reaction medium containing acetic acid; separating the reaction medium into a liquid recycle stream and a vapor product stream; Separating the vapor product stream in no more than two distillation columns to produce a crude acid product comprising acetic acid containing lithium cations; in the first processor, the crude acetic acid product is converted to an acid form cation exchanger. In a second processor, the intermediate acetic acid product is metal-exchanged with acid cation exchange sites in a second processor. A purified flow of acetic acid in contact with a second purifying resin comprising an ion exchange resin, wherein the first processing unit, the second processing unit, or both are individually on the processing unit side At least one sampling port disposed through the section; through the corresponding sampling port, a first purified resin, a second purified resin, a liquid sample of acetic acid stream present in the processing apparatus, or these Obtaining a sample of the combination; and determining the concentration of impurities in the at least one sample.

  [0045] In some embodiments, the method compares the impurity concentration of at least one sample with a previously determined impurity concentration value so that the impurity concentration of the sample is at the position of the sampling port from which the sample was obtained. The method further includes determining whether the purified resin is consumed at a corresponding position in the processing apparatus. In some embodiments, the method stops at least a portion of the exhausted resin by stopping the flow of acetic acid through the processor before substantially all of the active purified resin present in the processor is exhausted. And resuming the flow of acetic acid stream through the processor to produce a purified acetic acid stream.

  [0046] In some embodiments, the metal exchanged ion exchange resin comprises a strong acid exchange site occupied by at least 1% silver. In some embodiments, the crude acid product contains 10 ppm or less lithium.

  [0047] In some embodiments, separating the vapor product stream distills the vapor product stream in a first distillation column and recovers the side stream to obtain a distilled acetic acid product; Distilling the acetic acid product obtained in a second distillation column to produce a crude acid product comprising acetic acid and lithium cations. In some embodiments, the method includes a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide before distilling the distilled acetic acid product in the second distillation column. The method further comprises adding to the distilled acetic acid product; removing at least a portion of the potassium by the acid form cation exchanger.

  [0048] In some embodiments, the crude acetic acid product is contacted with a cation exchanger at a temperature of 50 ° C to 120 ° C. In some embodiments, the intermediate acetic acid product is contacted with a metal exchanged ion exchange resin at a temperature of 50 ° C. to 85 ° C .; or a combination thereof. In some embodiments, the intermediate acetic acid product has a lithium ion concentration of less than 50 ppb.

  [0049] In some embodiments, the acid form cation exchanger comprises a resin in a strong acid cation exchange macroreticular, macroporous, or mesoporous resin in acid form. In some embodiments, the method further comprises treating the purified acetic acid product with a cation exchange resin to recover silver, mercury, palladium, or rhodium. In some embodiments, the water concentration in the reaction medium is controlled to 0.1 to 5% by weight based on the total amount of reaction medium present.

  [0050] In some embodiments, the method introduces a lithium compound selected from the group consisting of lithium acetate, lithium carboxylate, lithium carbonate, lithium hydroxide, and mixtures thereof into the reactor, It further includes maintaining a concentration of 0.3-0.7 wt% lithium acetate in the reaction medium. In some embodiments, the process maintains a hydrogen iodide concentration of 0.1 to 1.3 wt% in the reaction medium; maintains a rhodium catalyst concentration of 300 to 3000 wppm in the reaction medium; Further comprising maintaining a water concentration of 0.1-4.1 wt% in the medium; maintaining a methyl acetate concentration of 0.6-4.1 wt% in the reaction medium; or a combination thereof.

  [0051] In some embodiments, the method further comprises controlling the butyl acetate concentration in the acetic acid product to 10 wppm or less without directly removing the butyl acetate from the acetic acid product. In some embodiments, the butyl acetate concentration maintains an acetaldehyde concentration of 1500 ppm or less in the reaction medium; the temperature in the reactor is controlled at 150-250 ° C .; the hydrogen partial pressure in the reactor is 0.3 Controlled by controlling the rhodium catalyst concentration in the reaction medium to 100 to 3000 wppm; or by performing a combination thereof.

  [0052] In some embodiments, the method further comprises controlling the ethyl iodide concentration in the reaction medium to 750 wppm or less. In some embodiments, the propionic acid concentration in the product acetic acid is less than 250 wppm without removing propionic acid directly from the product acetic acid; the propionic acid in the reaction medium is ethyl iodide and the propionic acid in the acetic acid product is Present in a weight ratio of 3: 1 to 1: 2; acetaldehyde and ethyl iodide are present in the reaction medium in a weight ratio of 2: 1 to 20: 1; ethanol concentration in the methanol feed stream into the reactor Is less than 150 wppm; or a combination thereof. In some embodiments, the ethyl iodide concentration in the reaction medium adjusts 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. Control by doing.

Acetic acid production system:
[0053] The process for producing acetic acid by methanol carbonylation advantageously divides into three main areas: reaction system and process; light fraction recovery / acetic acid product separation system and process; and product acetic acid purification system and process; be able to.

  [0054] An acetic acid process suitable for purposes in the present invention where steam is generated from a carbonylation reactor, which is then distilled in a light fraction column to produce the acetic acid product as a side stream, is purified It can vary in the system and process, including the flow, recycle stream, type and number of distillation columns used, various purification processes used, and the like. Examples of suitable processes include: US-3769329; US-377156; US-4039395; US-4255551; US-4615806; US-5001259; US-5026908; US-5144068; US-5233707; US Pat. No. 5,683,492; US Pat. No. 5,683,492; US Pat. No. 6,583,120; US Pat. No. 6,531,522; US Pat. US-7223883; US-7223886; US-7271293; US-7476761; US-738771; US-7855306; U US-200060247466; US-20090259072; US-2010288333; US-20120090981; US-201200780112; US-202008181; US-2013261334; US-2013281735; EP-01621420; Etc. (all the contents and disclosures of which are incorporated herein by reference). A method for producing acetic acid according to some aspects disclosed herein, generally designated as process 100, is illustrated in FIG.

  [0055] A low water, low energy process for producing acetic acid by carbonylation of methanol, including a rhodium catalyst system operated with less than 14 wt% water and using no more than two distillation columns in the main purification series Was developed. The main purification series is aimed at removing bulk components such as water, methyl acetate, methyl iodide, and hydrogen iodide from the vapor product stream from the reactor / flasher to obtain acetic acid. This main purification series receives the majority of the vapor stream from the reactor and obtains acetic acid as the final acetic acid. For example, main purification series columns include light fraction columns and dry columns. From this main purification series, columns whose primary function is to remove trace components such as acetaldehyde, alkanes, and propionic acid may be eliminated.

  [0056] The process for producing acetic acid may produce cations that accumulate in the crude acid product. These residual cations can be difficult to remove and can adversely replace iodide in the last metal exchange protection bed. Thus, the final product may have unacceptable levels of iodide despite the use of a metal exchange guard bed. The present invention provides a method for removing cations.

[0057] Sources of cations may come from various promoters, cocatalysts, additives, in situ reactions, and the like. For example, a low water, low energy process involving the use of promoters such as lithium iodide that may be formed in situ after adding lithium acetate or other compatible lithium salt to the reaction mixture. Thus, the process stream may contain some amount of lithium ions. In addition, this process uses a maximum of two distillation columns in the main purification series, and preferably the main purification does not include a column for removing heavy fraction material, so that the crude acid product is lithium-like. in addition to a cationic, larger alkyl iodide compounds, for example, may contain a C ₁₀ -C ₁₄ alkyl iodides. Sometimes more than 10%, or even more than 50% of the iodide present has an organic chain length greater than 10 carbon atoms. Thus, there may be more than 10 ppb, such as more than 20 ppb, more than 50 ppb, more than 100 ppb, or more than 1 ppm C ₁₀ -C ₁₄ alkyl iodide. In addition to the usual shorter chain length iodide impurities found in the crude acid products of iodide-promoted carbonylation processes such as methyl iodide, HI, and hexyl iodide, these higher alkyl iodides are May exist. Conventional iodide impurities are usually removed from the crude acid product using a metal exchanged strong acid ion exchange resin where the metal is, for example, silver or mercury. However, the silver or mercury in the metal-exchanged strong acid ion exchange resin is replaced by residual lithium, resulting in a lower capacity and efficiency of the resin and the possibility of contaminating the product with silver or mercury It was found that there was a possibility.

  [0058] The cations in the crude acid product are organolithium salts such as those described in CN-101053841 and CN-1349855, the contents of all of which are incorporated herein by reference. This may be due to the use of an organic alkali salt ligand such as a ligand. CN-101053841 describes a ligand containing lithium acetate or lithium oxalate. CN-1349855 describes a bimetallic catalyst having a cis-dicarbonylrhodium structure in which a metal lithium organic ligand is coordinated. Metallic lithium organic ligands 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 It may be a pyridine derivative. In fact, it is believed that all lithium salt components of these ligands generate lithium iodide in situ in the reaction medium after exposure to methyl iodide at the reaction temperature and pressure in the carbonylation reactor. At least some small proportion of the lithium component is entrained in the purification system. Thus, the purification system according to the present invention can also remove lithium formed in situ from the use of these types of organic ligands.

  [0059] The cation also uses a bimetallic Rh chelate catalyst having an amine function, such as those described in CN-1640543, the entire contents and disclosure of which are incorporated herein by reference. Possibly as a result of the use of non-lithium salts. According to CN-1604543, the cationic species contains N and O donor atoms and is formed from aminobenzoic acid. The amine can be quaternized with methyl iodide in situ in the reaction medium at the reaction temperature and pressure to form a quaternary nitrogen cation. The quaternary nitrogen cation, like the lithium cation, may be sent with the crude acid product, which can be removed using the present invention prior to the metal exchange protection bed.

  [0060] Some embodiments carbonylate methanol, dimethyl ether, and / or methyl acetate in the presence of 0.1 to less than 14 wt% water, metal catalyst, methyl iodide, and lithium iodide. Includes a low water and low energy process for producing acetic acid. In some embodiments, no more than two distillation columns (e.g., a light fraction column and a water removal or dehydration column are used without a third “heavy fraction column”) in the main purification series, The resulting acidic acid product is purified with an acid form cation exchanger to remove residual lithium ions and then an acid comprising at least one metal selected from the group consisting of silver, mercury, palladium, and rhodium Low energy process with metal exchanged ion exchange resin with cation exchange sites. The metal exchanged ion exchange resin may have at least 1% of the strong acid exchange sites occupied by silver, mercury, palladium and / or rhodium, for example at least 1% silver, mercury, palladium and / or rhodium. Having 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. It's okay. For processes using no more than two distillation columns in the main purification series by removing lithium using a cation exchanger prior to using a resin having a metal-exchanged strong acid cation site, from the metal-exchanged site by lithium Substitution, silver, mercury, palladium, and / or rhodium is reduced or eliminated. In some embodiments, in addition to the main purification series, distillation columns in other purification systems such as an acetaldehyde removal system that removes acetaldehyde and other PRCs from the methyl iodide phase prior to returning methyl iodide to the reaction medium. Can be used to remove impurities from the reactor components.

[0061] A particularly preferred process is one that uses a cation exchanger to remove lithium, and then uses a silver exchanged cation substrate to remove iodide. Crude acid product contains organic iodides with an aliphatic chain length to C ₁₀ or higher in many cases, this has to be removed. Sometimes more than 10% of the iodide present, such as more than 30%, or even more than 50% has an organic chain length of more than 10 carbon atoms.

  [0062] In the absence of heavy fractions and other finishing equipment, decyl iodide and dodecyl iodide are particularly prevalent and these are difficult to remove from the product. The silver exchanged cationic substrate of the present invention typically removes over 90% of such iodides. Often, the crude acid product has 10 to 1000 ppb total iodide prior to processing, which makes the product unusable for iodide sensitive applications.

  [0063] In the crude acid product prior to the iodide removal process, an iodide level of 20 ppb to 1.5 ppm is normal; in contrast, the iodide removal process is preferably total iodide present. Is operated to remove at least about 95%. In a typical embodiment, the lithium / iodide removal treatment involves contacting the crude acid product with a cation exchanger to remove more than 95% of the lithium ions, and then the crude acid product is silver-exchanged sulfonic acid functional. 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 contact with the resin.

  [0064] Lithium has also been found to be entrained in the crude acid product when heavy fractions and other finishing equipment are not used. Even a very small amount of 10 ppb lithium in the crude acid product can cause problems with respect to iodide removal. In the acid-containing crude acid product discharged from the drying column of the acetic acid process, for example, the last column in the main purification series, 10 ppm or less, for example, 5 ppm or less, 1 ppm or less, 500 ppb or less, 300 ppb based on the weight of the crude acid product Less than or less than 100 ppb lithium can be present. With respect to the range, 0.01 ppm to 10 ppm, such as 0.05 ppm to 5 ppm, or 0.05 ppm to 1 ppm of lithium can be present in the crude acid product. A substantial amount of lithium can be removed by using an acid form cation exchanger prior to introducing the crude acid product into the metal exchanged resin. For example, more than 90%, such as 95% or 99% by weight of lithium in the stream can be removed by the cation exchanger. Thus, the stream discharged from the acid form cation exchanger may contain less than 50 ppb lithium, for example less than 10 ppb, or less than 5 ppb. Such removal of lithium can greatly extend the life of the metal-exchanged resin.

Reaction system and process:
[0065] As shown in FIG. 1, a process 100 for producing acetic acid includes a reaction system that includes a carbonylation reactor 104, wherein a portion of the reaction medium is continuously removed from the carbonylation reactor through line 113; The reaction medium is separated from acetic acid and other volatile components and subjected to flash or low pressure distillation in a separation system, such as flasher 112, used to recycle non-volatile components back into the reaction medium through stream 110. The volatile components of the reaction medium are then routed through overhead line 122 into the light fraction collection / acetic acid product separation system and process initiated at light fraction column 124.

  [0066] As shown in FIG. 1, a methanol-containing feed stream 101 and a carbon monoxide-containing feed stream 102 are sent into the liquid phase reaction medium of the carbonylation reactor 104 to provide catalyst, water, methyl iodide, methyl acetate, The carbonylation reaction is carried out in a reaction medium containing acetic acid, iodide salt, HI, and other reaction medium components.

  [0067] In some embodiments, the carbonylation reactor 104 may be a stirred vessel, a bubble column type vessel, or a combination thereof, in which the reaction solution or slurry content is at a level suitable for normal operation. To maintain. In some embodiments, carbon monoxide can be continuously introduced into the reaction medium of the carbonylation reactor, for example, below the stirrer used to stir the contents. The gas feed stream is preferably well dispersed throughout the reaction liquid by this stirring means. In some embodiments, the reactor system includes a plurality of recirculation lines (in which various components are recycled back into the reaction medium from other parts of the process), and various steam purge lines (further. Can be further included). As will be readily appreciated by those skilled in the art, all exhaust and other steam purge lines are connected to one or more scrubber systems 139 so that all condensable components are finally discharged before releasing the steam stream into the atmosphere. It should be understood that it is recycled back into the carbonylation reactor.

  [0068] In some embodiments, the gas purge stream 106 is discharged from the reactor 104 to the scrubber system 139 to prevent the accumulation of gaseous byproducts, carbon monoxide partial pressure and / or total reactor pressure. Can be controlled. The reactor system can further include a pump around loop 103 to control the temperature of the reactor.

  [0069] In some embodiments, the reaction medium comprises a metal catalyst, or a Group 9 metal catalyst, or a catalyst comprising rhodium and / or iridium. In some embodiments, the reaction medium includes a rhodium catalyst.

  [0070] In some embodiments, the rhodium component of the catalyst system may be present in the form of a coordination compound of rhodium and a halogen component that provides at least one ligand of the coordination compound. In addition to the coordination of rhodium and halogen, it is also believed that carbon monoxide coordinates with rhodium. In some embodiments, the rhodium component of the catalyst system may include rhodium salts such as rhodium metal, oxides, acetates, iodides, carbonates, hydroxides, chlorides, or rhodium distribution in the reaction atmosphere. Rhodium in the form of other compounds that form coordination compounds can be provided by introduction into the reaction zone. In another embodiment, the carbonylation catalyst comprises rhodium dispersed in a liquid reaction medium or supported on an inert solid. Rhodium can be introduced into the reaction system in any number of forms and the actual nature of the rhodium component within the active catalyst complex may be uncertain.

[0071] In some embodiments, the catalyst concentration in the reactor is maintained in an amount of about 200 to about 5000 ppm by weight, based on the total weight of the reaction medium.
[0072] In some embodiments, the reaction medium can further include a halogen-containing catalyst promoter. Suitable examples include organic halides, alkyls, aryls, and substituted alkyls or aryl halides. In some embodiments, the halogen-containing catalyst promoter is present in the form of an alkyl halide corresponding to the alkyl group of the feed alcohol where the alkyl group is carbonylated. Thus, in the carbonylation of methanol to acetic acid, the halide accelerator includes methyl halide or methyl iodide (MeI). In some embodiments, the reaction medium comprises about 5% or more MeI by weight based on the total weight of the reaction medium. In some embodiments, the reaction medium comprises about 5 wt% or more and about 50 wt% or less MeI. In some embodiments, the reaction medium comprises about 7 wt% or 10 wt% MeI and no more than about 30 wt% or 20 wt% MeI, based on the total weight of the reaction medium.

  [0073] In some embodiments, the liquid reaction medium used can include any solvent that is compatible with the catalyst system, such as pure alcohol, or alcohol feed and / or product carboxylic acid and / or Mention may be made of mixtures of esters of these two compounds. In some embodiments, the solvent used in the liquid reaction medium comprises acetic acid (AcOH). In some embodiments, the reaction medium comprises about 50 wt% or more AcOH. In some embodiments, the reaction medium comprises greater than or equal to about 50 wt% and less than or equal to about 90 wt% AcOH. In some embodiments, the reaction medium comprises about 50 wt% or 60 wt% or more AcOH and no more than about 80 wt% or 70 wt% AcOH, based on the total weight of the reaction medium.

  [0074] In some embodiments, the reaction medium comprises at least a limited concentration of water. In some embodiments, the reaction medium includes a detectable amount of water. In some embodiments, the reaction medium includes about 0.001% or more water by weight. In some embodiments, the reaction medium comprises about 0.001 wt% or more and about 14 wt% or less water. In some embodiments, the reaction medium is about 0.05%, or 0.1%, or 0.5%, or 1%, or 2% by weight, based on the total weight of the reaction medium. Or 3 wt%, or 4 wt% or more of water, and about 10 wt% or 5 wt% or less of water.

  [0075] In some embodiments, the reaction medium further comprises an ester of a carboxylic acid product and an alcohol used in the carbonylation. In some embodiments, the reaction medium includes methyl acetate. In some embodiments, the reaction medium comprises about 0.5 wt% or more methyl acetate (MeAc). In some embodiments, the reaction medium comprises about 1 wt% or more and about 50 wt% or less MeAc. In some embodiments, the reaction medium is about 1.5 wt%, or 2 wt%, or 3 wt% or more MeAc, based on the total weight of the reaction medium, no more than about 20 wt% or 10 wt% Of MeAc.

  [0076] In some embodiments, the reaction medium further comprises further iodide ions in addition to the iodide ions present as hydrogen iodide. In some embodiments, the iodide ion concentration is provided by an iodide salt or lithium iodide (LiI). In some embodiments, the reaction medium is maintained at a low water concentration and methyl acetate and lithium iodide are present in concentrations sufficient to function as rate enhancers (see US-5001259).

  [0077] In some embodiments, at least a portion of the iodide ion concentration in the reaction medium is a metal iodide salt, or an organic cation, or an iodide salt of a cation based on a quaternary amine, phosphine, or the like. Derived from. In some embodiments, the iodide is a metal salt, a Group 1 or Group 2 iodide salt. In some embodiments, the reaction medium comprises an alkali metal iodide or lithium iodide. In some embodiments, the iodide concentration is greater than the iodide ions present as hydrogen iodide. In some embodiments, the reaction medium includes an amount of iodide salt or lithium iodide sufficient to produce a total iodide ion concentration of greater than about 2% by weight. In some embodiments, the reaction medium comprises an amount of iodide salt or iodide sufficient to produce a total iodide ion concentration of about 2 wt% or more and about 40 wt% or less, based on the total weight of the reaction medium. Contains lithium fluoride. In some embodiments, the reaction medium is about 5 wt.%, Or 10 wt.%, Or 15 wt.% Or more iodide ions, based on the total weight of the reaction medium, and not more than about 30 wt.% Or 20 wt.%. Of iodide ions.

  [0078] In some embodiments, the reaction medium can further include hydrogen measured according to the hydrogen partial pressure present in the reactor. In some embodiments, the hydrogen partial pressure in the reactor is about 0.7 kPa (0.1 psia), or 3.5 kPa (0.5 psia), or greater than or equal to 6.9 kPa (1 psia). It is below 03 MPa (150 psia), or 689 kPa (100 psia), or 345 kPa (50 psia), or 138 kPa (20 psia).

  [0079] In some embodiments, the reactor temperature, ie, the temperature of the reaction medium, is about 150 ° C or higher. In some embodiments, the reactor temperature is about 150 ° C. or higher and about 250 ° C. or lower. In some embodiments, the reactor temperature is about 180 ° C. or higher and about 220 ° C. or lower.

  [0080] In some embodiments, the carbon monoxide partial pressure in the reactor is about 200 kPa or more. In some embodiments, the CO partial pressure is about 200 kPa or more and about 3 MPa or less. In some embodiments, the CO partial pressure in the reactor is about 300 kPa, or 400 kPa, or 500 kPa or more and about 2 MPa or 1 MPa or less. Total reactor pressure represents the sum of the partial pressures of all reactants, products and by-products present therein. In some embodiments, the total reactor pressure is about 1 MPa or more and about 4 MPa or less.

  [0081] In some embodiments, the liquid reaction medium is withdrawn from the carbonylation reactor 104 at a rate sufficient to maintain a constant level therein, resulting in a lower pressure than is present in the reactor. Is introduced into the flasher 112 at an intermediate position between its top and bottom. In the flasher, the less volatile component, ie catalyst solution, is discharged as bottom stream 110 (acetic acid containing mainly rhodium and iodide salts with smaller amounts of methyl acetate, methyl iodide, acetic acid, and water) and reacted. Recirculate back into the medium. The flasher overhead stream 122 contains primarily product acetic acid along with methyl iodide, methyl acetate, water, and PRC. Some of the carbon monoxide and gaseous by-products such as methane, hydrogen, carbon dioxide, etc. can also be discharged from the top of the flasher.

[0082]
Light fraction recovery / acetic acid product separation system and method:
[0083] In some embodiments, the overhead stream from flasher 112 is sent as stream 122 to a light fraction column 124, also referred to in the art as a stripper column, where it is distilled, in the present invention the first column. A low boiling overhead vapor stream 126, also referred to as a top stream 126, and in some embodiments a purified acetic acid product stream 128 that is removed as a side stream are produced. The light distillate column 124 further produces a high boiling residue stream 116 that can be subjected to further purification and / or can be recycled back into the reaction medium.

  [0084] In some embodiments, the first overhead stream 126 is condensed and then sent to an overhead phase separation unit 134, also referred to as an overhead decanter in the present invention. In some embodiments, the first overhead stream 126 includes methyl iodide, methyl acetate, acetic acid, water, and at least one PRC. In some embodiments, the condensed first overhead stream 126 comprises water, acetic acid, methyl iodide, methyl acetate, and at least one permanganate reducing compound (PRC), such as acetaldehyde. A light aqueous phase 135; and a heavy phase 137 containing methyl iodide, methyl acetate (which may also contain at least one PRC).

  [0085] In some embodiments, 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 through lines 118 and 114, respectively. In some embodiments, if desired, a portion of the light phase stream 135 can be recycled to the reaction medium in stream 114 to supply water to the reaction medium. In some embodiments, heavy phase 137 is recycled through 118 to the reactor.

  [0086] In some embodiments, the light phase 135, the heavy phase 137, or a combination thereof is sent through stream 142 to one or more purification processes 108, such as an aldehyde removal system. The resulting purified stream is then returned to the process by one or more streams (collectively referred to as 155).

  [0087] Although the specific composition of the light liquid phase 135 can vary widely, some representative compositions are given in Table 1 below.

  [0088] In one aspect, the overhead decanter 134 is arranged and configured to maintain a low interface level to prevent excessive retention of methyl iodide. Although the specific composition of the heavy liquid phase 137 can vary widely, some representative compositions are given in Table 2 below.

  [0089] Although not shown, the light liquid phase 135 and / or a portion of the heavy liquid phase 137 are separated and sent to an acetaldehyde or PRC removal system to recover methyl iodide and methyl acetate while removing the acetaldehyde can do. As shown in Tables 1 and 2, the light liquid phase 135 and / or the heavy liquid phase 137 each contain PRC and the process removes carbonyl impurities such as acetaldehyde that degrade the quality of the acetic acid product. These are described in US Pat. Nos. 6,143,930; 6,339,171; 7,223,883; 7,223,886; 7,855,306; 7,884,237; , 889,904; and US Publication 2006/0011462; which are incorporated herein by reference in their entirety, can be removed with suitable impurity removal columns and absorbers. Carbonyl impurities such as acetaldehyde can react with iodide catalyst promoters to form alkyl iodides such as ethyl iodide, propyl iodide, butyl iodide, pentyl iodide, hexyl iodide, and the like. Also, since many impurities are derived from acetaldehyde, it is desirable to remove carbonyl impurities from the liquid light phase.

  [0090] The portion of the light liquid phase 135 and / or heavy liquid phase 137 supplied to the acetaldehyde or PRC removal system may be from 1% of the mass flow rate of either the light liquid phase 133 and / or the heavy liquid phase 134. It can be varied at 99%, for example 1-50%, 2-45%, 5-40%, 5-30%, or 5-20%. Also, in some embodiments, a portion of both the light liquid phase 135 and the heavy liquid phase 137 can be fed to the acetaldehyde or PRC removal system. The portion of the light liquid phase 135 that is not fed to the acetaldehyde or PRC removal system can be refluxed to the first column or recycled to the reactor as described herein. The portion of the heavy liquid phase 137 that is not fed to the acetaldehyde or PRC removal system can be recycled to the reactor. Although a portion of the heavy liquid phase 137 can be refluxed to the first column, it is more desirable to return the heavy liquid phase 137 enriched in methyl iodide to the reactor.

  [0003] In one embodiment, a portion of the light liquid phase 135 and / or heavy liquid phase 137 is fed to a distillation column and the overhead stream is concentrated to have acetaldehyde and methyl iodide. Depending on the configuration, there can be two separate distillation columns and the second column overhead stream can be enriched with acetaldehyde and methyl iodide. Dimethyl ether, which can be formed in-situ, can also be present in the overhead stream. The overhead stream can be subjected to one or more extraction stages to remove methyl iodide enriched raffinate and extractant. A portion of the raffinate can be returned to the distillation column, first column, overhead decanter, and / or reactor. For example, if the heavy liquid phase 137 is processed in a PRC removal system, it may be desirable to return a portion of the raffinate to either the distillation column or the reactor. Also, for example, when the light liquid phase 135 is processed in a PRC removal system, it may be desirable to return a portion of the raffinate to either the first column, the overhead decanter, or the reactor. In some embodiments, the extractant can be further distilled to remove water, which is returned to one or more extraction stages. Those containing more methyl acetate and methyl iodide than the light liquid phase 135 can also be recycled to the reactor 104 and / or refluxed to the first column 124.

  Suitable purification processes include: US-6143930; US-6339171; US-7223883; US-7223886; US-8076507; US-20130303800; US-20130310603; US-200900367710; US-201300116470; US-201303014414; US-20130261334; US-2013264186; or 2013030281735; all of which are incorporated herein by reference.

Product purification systems and processes:
[0091] In some embodiments, the acetic acid stream 128 can be subjected to further purification, such as in a drying column 130, where acetic acid is recovered as a column bottoms stream and the aqueous overhead stream is passed into the overhead decanter 148. It can be recovered and a portion of it can be refluxed back into the drying column 130 before being returned to the reactor 104. Other embodiments send acetic acid to the heavy fraction column (see WO-0216297) and / or one or more absorptions within the resin bed or protective column 200 as described more fully herein. Contact with an agent, adsorbent, or ion exchange resin to remove various impurities, etc. within the product purification section of the process (see US-6657078). As shown, the drying column 130 separates the acetic acid side stream 128 into a top stream comprising primarily water and a bottom stream comprising primarily acetic acid. The overhead stream is cooled and condensed in a phase separation unit, such as decanter 148, to form a light phase and a heavy phase. As shown, a portion of the light phase is refluxed and the remainder of the light phase is returned to the reactor. The heavy phase, usually an emulsion containing water and methyl iodide, is preferably returned entirely to the reactor. A typical composition for the light phase of the dry column overhead is given in Table 3 below.

  [0092] In some embodiments, a small amount of alkaline components, such as KOH, can be added to the side stream 128 prior to introduction into the drying column 130. In other embodiments, the alkaline component is added to the drying column 130 at the same level as the stream 128 that is introduced into the drying column 130 or at a height that is above the height level of the stream 128 that is introduced into the drying column 130. You can also. By such addition, HI in the column can be neutralized.

  [0093] In some embodiments, the drying column bottoms stream may comprise or consist essentially of acetic acid. In some embodiments, the dry column bottoms stream comprises an amount of acetic acid that is greater than 90 wt%, such as greater than 95 wt% or greater than 98 wt%. In some embodiments, the stream is also substantially anhydrous and includes, for example, less than 0.15 wt% water, such as less than 0.12 wt% water, or less than 0.1 wt% water. However, as discussed, this flow can contain various levels of impurities.

  [0094] In FIG. 1, the crude acid product is discharged as a residue in the dry column bottoms stream 146. In some embodiments, the crude acid product from the drying column 130 can be recovered from the side stream at a position slightly above the bottom of the column 130. This side stream can be discharged in the liquid or vapor phase. If discharged in the vapor phase, further condensation and cooling may be required before removing alkaline contaminants, such as lithium contaminants. For example, the crude acid product can be recovered as a side stream from the bottom portion of the column, while the residue stream is discharged from the bottom of the drying column 130 and removed or recycled. This side stream contains the crude acetic acid product and is sent to a cation exchange resin to remove lithium. This can allow the higher boiling fraction to be separated from the crude acid product in the residue stream. In some embodiments, the residue stream is discarded or purged from the process 100.

  [0095] In some embodiments, the crude acid product produced by the drying column 130 is passed through a series of metal-functionalized iodide-removing ion exchange resins prior to storage or transportation for commercial use. Further processing. In some embodiments, the process of producing acetic acid involves introducing a lithium compound into the reactor to maintain a concentration of 0.3-0.7 wt% lithium acetate in the reaction medium. In addition. In some embodiments, a predetermined amount of lithium compound is introduced into the reactor to maintain a concentration of 0.1 to 1.3 weight percent hydrogen iodide in the reaction medium. In some embodiments, based on the total weight of the reaction medium present in the carbonylation reactor, the concentration of rhodium catalyst is maintained in the reaction medium at an amount of 300-3000 wppm and the concentration of water in the reaction medium. An amount of 0.1-4.1% by weight is maintained and the concentration of methyl acetate is maintained at 0.6-4.1% by weight in the reaction medium.

  [0096] In some embodiments, the lithium compound introduced into the reactor is selected from the group consisting of lithium acetate, lithium carboxylate, lithium carbonate, lithium hydroxide, other organic lithium salts, and mixtures thereof. The In some embodiments, the lithium compound is soluble in the reaction medium. In one embodiment, lithium acetate dihydrate can be used as a source material for the lithium compound.

  [0097] Lithium acetate has the following equilibrium reaction (I):

React with hydrogen iodide to form lithium iodide and acetic acid.
[0098] Lithium acetate is believed to provide improved control of hydrogen iodide concentration over other acetates such as methyl acetate present in the reaction medium. Without being bound by theory, lithium acetate is a conjugate base of acetic acid and is therefore reactive to hydrogen iodide by an acid-base reaction. This property is believed to result in an equilibrium of reaction (I) that advantageously produces a reaction product over that produced by the corresponding equilibrium of methyl acetate and hydrogen iodide. This improved equilibrium is driven by a concentration of less than 4.1% water in the reaction medium. In addition, the relatively low volatility of lithium acetate compared to methyl acetate allows lithium acetate to be retained in the reaction medium with the exception of volatilization losses and small amounts of entrainment in the crude steam product. In contrast, the relatively high volatility of methyl acetate makes it more difficult for the material to distill into the purification series and to control the methyl acetate. Lithium acetate is much easier to hold and control during the process at a stable and low concentration of hydrogen iodide. Accordingly, a relatively small amount of lithium acetate can be used as compared to the amount of methyl acetate required to control the hydrogen iodide concentration in the reaction medium. Furthermore, lithium acetate has been found to be at least three times more effective than methyl acetate in promoting oxidative addition of methyl iodide to rhodium [I] complexes.

  [0099] In some embodiments, the concentration of lithium acetate in the reaction medium is 0.3 wt% or more, or 0.35 wt% or more, or 0, as determined by perchloric acid titration to the end of potentiometric titration. Maintained at 4 wt% or higher, or 0.45 wt% or higher, or 0.5 wt% or higher, and / or in some embodiments, the concentration of lithium acetate in the reaction medium is 0.7 wt% Or less, 0.65% by weight or less, 0.6% by weight or less, or 0.55% by weight or less.

  [0100] It has been found that excess lithium acetate in the reaction medium can adversely affect other compounds in the reaction medium and reduce productivity. Conversely, it has been found that a lithium acetate concentration in the reaction medium of less than about 0.3% by weight results in a lack of control over the hydrogen iodide concentration in the reaction medium.

  [0101] In some embodiments, the lithium compound can be introduced continuously or intermittently into the reaction medium. In some embodiments, the lithium compound is introduced during reactor startup. In some embodiments, the lithium compound is introduced intermittently to compensate for entrainment losses.

[0102] To demonstrate the promoting effect of lithium acetate in the carbonylation reactor and to determine the effect of lithium acetate on the oxidative addition of methyl iodide to the rhodium complex: Li [RhI ₂ (CO) ₂ ] A series of experiments confirmed the effect of lithium acetate on the reaction rate. A linear increase in the reaction rate correlated with an increase in lithium acetate concentration was observed. This correlation showed a primary promoting effect of the reaction between methyl iodide and Li [RhI ₂ (CO) ₂ ]. These experiments further show non-zero inhibition, which means that lithium acetate is not essential for causing the MeI-Rh (I) reaction, but lithium acetate provides a significant promoting effect even at low concentrations. Was confirmed.

  [0103] In some embodiments, the method can further comprise maintaining the butyl acetate concentration in the acetic acid product below 10 wppm without directly removing the butyl acetate from the product acetic acid. . In some embodiments, the butyl acetate concentration in the final acetic acid product is determined by removing acetaldehyde from the reaction medium, for example, by removing acetaldehyde from a stream derived from the reaction medium, and / or the reaction temperature, And / or by controlling the hydrogen partial pressure and / or the metal catalyst concentration in the reaction medium, it can be kept below 10 ppm. In some embodiments, a carbonylation reaction temperature of 150 ° C. to 250 ° C., a hydrogen partial pressure in a carbonylation reactor of 0.3 to 2 atmospheres, in a reaction medium of 100 to 3000 wppm based on the total weight of the reaction medium. The butyl acetate concentration in the final acetic acid product is maintained by controlling one or more of the rhodium metal catalyst concentration and / or acetaldehyde concentration in the reaction medium of 1500 ppm or less.

  [0104] In some embodiments, the acetic acid product formed according to some embodiments of the methods disclosed herein is 10 wppm or less, or 9 wppm or less, or 8 wppm or less, based on the total weight of the acetic acid product, Alternatively, it has a butyl acetate concentration of 6 wppm or less, or 2 wppm or less. In some embodiments, the acetic acid product is substantially free of butyl acetate, i.e., has a butyl acetate concentration of less than 0.05 wppm, or is not detectable by detection means known in the art. In some embodiments, the acetic acid product can also have a propionic acid concentration of less than 250 wppm, or less than 225 ppm, or less than 200 wppm.

  [0105] In some embodiments, the butyl acetate concentration in the acetic acid product can be controlled by controlling the concentration of acetaldehyde in the reaction medium. While not wishing to be bound by theory, it is believed that butyl acetate is a byproduct resulting from the aldol condensation of acetaldehyde. Applicants have found that by maintaining the acetaldehyde concentration in the reaction medium below 1500 wppm, the concentration of butyl acetate in the final acetic acid product can be controlled below 10 wppm. In some embodiments, the acetaldehyde concentration in the reaction medium is maintained at 1500 wppm or less, or 900 wppm or less, or 500 wppm or less, or 400 wppm or less, based on the total weight of the reaction medium.

  [0106] In some embodiments, the butyl acetate concentration in the acetic acid product is controlled by controlling the reaction temperature of the carbonylation reactor to a temperature of 150 ° C or 180 ° C or higher and 250 ° C or 225 ° C or lower. And / or the hydrogen partial pressure in the carbonylation reactor is 0.3 atmospheres, or 0.35 atmospheres, or 0.4 atmospheres, or 0.5 atmospheres or more, 2 atmospheres, or 1 .5 atm or 1 atm or less can be controlled.

  [0107] Although a relatively high hydrogen partial pressure results in improved reaction rate, selectivity, improved catalytic activity, and reduced temperature, Applicants have found that as hydrogen partial pressure increases, such as butyl acetate It has been found that the generation of impurities also increases.

  [0108] In some embodiments, the hydrogen partial pressure changes the amount of hydrogen present in the carbon monoxide source material and / or increases or decreases the reactor effluent to increase the amount of hydrogen in the carbonylation reactor. It can be controlled by obtaining the desired hydrogen partial pressure.

  [0109] A series of experiments were conducted to show the effect of hydrogen partial pressure and acetaldehyde concentration in the reaction medium on the concentration of butyl acetate in the final acetic acid product. These experiments confirmed the correlation between the reduced butyl acetate concentration in the final acetic acid product and the relatively low acetaldehyde concentration in the reaction medium and / or the relatively low hydrogen partial pressure in the carbonylation reactor. It was. Experiments in which the acetaldehyde concentration in the reactor was maintained below 1500 ppm and the reactor hydrogen partial pressure was maintained below 0.6 atmospheres resulted in butyl acetate levels below 10 wppm in the final acetic acid product. Other experiments showed that an acetaldehyde concentration in the reactor of less than 1500 wppm and a reactor hydrogen partial pressure of 0.46 atmospheres resulted in a butyl acetate concentration of less than 8 wppm in the final acetic acid product. Similar conditions where the hydrogen partial pressure was 0.30 atmospheres gave a butyl acetate level below 6 wppm, and a hydrogen partial pressure of 0.60 atmospheres gave a butyl acetate concentration below 0.2 wppm in the final acetic acid product. It was. However, in comparative experiments where the hydrogen partial pressures were 0.4 and 0.3, respectively, but no aldehyde removal system was present and the acetaldehyde concentration in the reactor was higher than 1500 wppm, 13 wppm and 16 wppm acetic acid, respectively. A final acetic acid product having a butyl level was obtained.

  [0110] Applicants have further found that the concentration of propionic acid in the final acetic acid product can be affected by the concentration of butyl acetate in the acetic acid product. Thus, 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 can be controlled to be less than 250 wppm, or less than 225 wppm, or less than 200 wppm. In addition, the propionic acid and butyl acetate concentrations in the final acetic acid product can be controlled by controlling the content of ethanol in the reactor feed stream that may be present as an impurity in the methanol source material. In some embodiments, the concentration of ethanol in methanol fed to the carbonylation reactor is controlled to 150 wppm or less. In some embodiments, the ethanol concentration in the methanol feed to the reactor, if present, is 100 wppm, or 50 wppm, or 25 wppm or less.

  [0111] Applicants have further found that the formation of ethyl iodide can be influenced by a number of variables such as the concentration of acetaldehyde, ethyl acetate, methyl acetate, and methyl iodide in the reaction medium. It was. Furthermore, the ethanol content in the methanol source material, the hydrogen partial pressure, and the hydrogen content in the carbon monoxide source material affect the concentration of ethyl iodide in the reaction medium and consequently the propionic acid concentration in the final acetic acid product. It was found to give

  [0112] In some embodiments, the concentration of ethyl iodide in the reaction medium is maintained / controlled to be 750 wppm or less, or 650 wppm or less, or 550 wppm or less, or 450 wppm or less, or 350 wppm or less. In another embodiment, the concentration of ethyl iodide in the reaction medium is maintained / controlled at 1 wppm, or 5 wppm, or 10 wppm, or 20 wppm, or 25 wppm or more, 650 wppm, or 550 wppm, or 450 wppm, or 350 wppm or less.

  [0113] In some embodiments, the propionic acid concentration in the acetic acid product is further maintained without removing propionic acid from the acetic acid product by maintaining the ethyl iodide concentration in the reaction medium at 750 wppm or less. , Below 250 wppm.

  [0114] In some embodiments, the concentration of ethyl iodide in the reaction medium and propionic acid in the acetic acid product is from 3: 1 to 1: 2, or from 5: 2 to 1: 2, or from 2: 1 to It may be present in a weight ratio of 1: 2. In some embodiments, the acetaldehyde: ethyl iodide concentration in the reaction medium is maintained at a weight ratio of 2: 1 to 20: 1, or 15: 1 to 2: 1, or 9: 1 to 2: 1. .

  [0115] In some embodiments, the ethyl iodide concentration in the reaction medium controls at least one of hydrogen partial pressure, methyl acetate concentration in the reaction medium, methyl iodide concentration, and / or acetaldehyde concentration. Can be maintained by.

  [0116] A series of experiments conducted to determine the effects of acetaldehyde and other reaction conditions on the formation of ethyl revealed that the relationship between the acetaldehyde concentration in the reaction medium and the ethyl iodide concentration, and the ethyl iodide reactor. A relationship was shown between the concentration and the concentration of propionic acid in the final acetic acid product. In general, an ethyl iodide concentration of less than 750 wppm and an acetaldehyde concentration of less than 1500 wppm in the reaction medium resulted in a propionic acid concentration of less than 250 wppm in the acetic acid product.

Use of iodide removal bed / ion exchange resin:
[0117] In some embodiments, the product acetic acid stream may be contaminated with halide (eg, iodide) and lithium, and under a range of operating conditions, the acid form of the cation exchange resin, And a metal exchanged ion exchange resin having an acid cation exchange site comprising at least one metal selected from the group consisting of silver, mercury, palladium and rhodium. In some embodiments, the ion exchange resin composition is provided in a fixed bed. The use of fixed iodide removal beds to purify contaminated carboxylic acid streams is well documented in the art (eg, US Pat. Nos. 4,615,806; 5,653,853; 5,731,252; and 6,225,498 (all of which are incorporated herein by reference). In general, a contaminated liquid carboxylic acid stream is contacted with the ion exchange resin composition described above by flowing through a series of stationary fixed beds. Lithium contaminants are removed by the acid form cation exchanger. Next, halide contaminants, such as iodide contaminants, are removed by reacting with the metal of the ion exchanged resin that has been metal exchanged to form metal iodides. In some embodiments, a hydrocarbon group capable of associating with iodide, such as a methyl group, may be esterified with a carboxylic acid. For example, in the case of acetic acid contaminated with methyl iodide, methyl acetate is generated as a byproduct of iodide removal. The formation of this esterification product usually does not have a detrimental effect on the treated carboxylic acid stream.

  [0118] Similar iodide contamination problems may exist in acetic anhydride produced using rhodium-iodide catalyst systems. Thus, the process of the present invention can alternatively be used in the purification of crude acetic anhydride product streams.

  [0119] Cation exchangers in the acid form suitable for removing metal ion contaminants in the present invention include strong acid cation exchange resins such as strong acid macroreticular or macroporous resins such as Amberlyst® 15 resin ( DOW), Purolite C145, or Purolite CT145. The resin may also be a strong acid cation exchange mesoporous resin in acid form. Chelate resins and zeolites can also be used.

[0120] Suitable stable ion exchange resins used in connection with the present invention to produce silver or mercury exchange resins for iodide removal are typically macroreticular (macroporous) type "strong acids"", That is, of the" RSO ₃ H "type, which is classified as a sulfonic acid cation exchange resin. Particularly suitable ion exchange substrates include Amberlyst® 15, Amberlyst® 35, and Amberlyst® 36 resin (DOW) suitable for use at elevated temperatures. If the material is stable in the organic medium at the conditions of interest, i.e. does not chemically decompose or release silver or mercury into the organic medium in an unacceptable amount, other stable ion exchange substrates such as zeolites may be used. Can be used. Zeolite cation exchange substrates are disclosed, for example, in US Pat. No. 5,962,735, the disclosure of which is incorporated herein by reference.

  [0121] At temperatures above about 50 ° C, silver or mercury exchange cation substrates may have a tendency to release small amounts of silver or mercury on the order of 500 ppb or less, thus silver or mercury exchange. The substrate is chemically stable under the conditions of interest. More preferably, the silver loss is less than 100 ppb in the organic medium, and even more preferably less than 20 ppb in the organic medium. Silver loss can be slightly higher upon start-up. In any case, if desired, in addition to the bed of acid form cation material upstream of the silver or mercury exchange material, the bed of acid form cation material is located downstream of the silver or mercury exchange material, The released silver or mercury can be captured.

  [0122] The pressure during the contacting step with the exchange resin is limited only by the physical strength of the resin. In one aspect, the contacting is performed at a pressure in the range of 0.1 MPa to 1 MPa, such as 0.1 MPa to 0.8 MPa, or 0.1 MPa to 0.5 MPa. However, for reasons of convenience, both pressure and temperature can be defined so that preferably the contaminated carboxylic acid stream is treated as a liquid. Thus, for example, when operating at generally preferred atmospheric pressures based on economic considerations, the temperature can range from 17 ° C. (freezing point of acetic acid) to 118 ° C. (boiling point of acetic acid). It is within the scope of those skilled in the art to define similar ranges for product streams containing other carboxylic acid compounds. The temperature of the contacting step is preferably kept low enough to minimize resin degradation. In one aspect, the contacting is performed at a temperature in the range of 25 ° C to 120 ° C, such as 25 ° C to 100 ° C, or 50 ° C to 100 ° C. Some cationic macroreticular resins usually begin to degrade significantly (by an acid-catalyzed aromatic desulfonation mechanism) at a temperature of 150 ° C. Carboxylic acids having 5 or fewer carbon atoms, such as 3 or fewer carbon atoms, maintain a liquid state at these temperatures. Thus, the temperature during contact must be kept below the decomposition temperature of the resin used. In some embodiments, the operating temperature is maintained below the temperature limit of the resin consistent with the desired reaction kinetics for liquid phase operation and lithium and / or halide removal.

  [0123] The composition of the resin bed within the acetic acid purification series can vary widely, but the cation exchanger must be placed upstream of the metal exchanged resin. In a preferred embodiment, the resin bed is placed after the final drying column. Preferably, the resin bed is placed at a location where the temperature of the crude acid product is low, for example below 120 ° C or below 100 ° C. The stream in contact with the acid form cation exchange resin and the stream in contact with the metal exchanged resin can be adjusted to the same or different temperatures. For example, the flow in contact with the cation exchange resin in the acid form can be adjusted to a temperature of 25 ° C to 120 ° C, such as 25 ° C to 85 ° C, 40 ° C to 70 ° C, such as 40 ° C to 60 ° C, while The flow in contact with the metal exchanged resin can be adjusted to a temperature of 50 ° C to 100 ° C, such as 50 ° C to 85 ° C, 55 ° C to 75 ° C, or 60 ° C to 70 ° C. In addition to the advantages discussed above, operation at lower temperatures results in less corrosion compared to operation at higher temperatures. Operation at lower temperatures results in less formation of corrosive metal contaminants, which can reduce the overall resin life as discussed above. Also, lower operating temperatures result in less corrosion, so there is no need to form the container with an expensive corrosion-resistant metal, and lower grade metals such as standard stainless steel can be used. .

  [0124] Returning to FIG. 1, the dry column bottoms stream is first passed through a cation exchange resin bed 200 to remove lithium ions. Although one cation exchange resin bed 200 is shown, it should be understood that multiple cation exchange resin beds can be used in series or in parallel. The cation exchange bed also has other cations such as potassium present in the stream when added to the drying column 130 as a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide, and corrosion. The metal can also be removed. The resulting exchanged stream, such as an intermediate acid product, was then metal exchanged with an acid cation exchange site comprising at least one metal selected from the group consisting of silver, mercury, palladium, and rhodium. Passing through an ion exchange resin bed, iodide can be removed from the stream to produce purified product 146. Although the purified resin is indicated by block 200, it should be understood that multiple metal exchanged ion exchange resin beds can be used in series or in parallel. In addition to the resin bed, a heat exchanger (not shown) can be placed in front of either resin bed to adjust the temperature of streams 146 and 182 to an appropriate temperature before contacting the resin bed. . Similarly, the crude acetic acid product can be fed to the cation exchange resin bed from a dry column side stream. A heat exchanger or condenser can be placed in front of either resin bed to adjust the temperature of the stream to an appropriate temperature before contacting the resin bed.

  [0125] In one aspect, the flow rate through the resin bed is between 0.1 bed volume / hour (BV / hour) to 50 BV / hour, such as 1 BV / hour to 20 BV / hour, or 6 BV / hour to 10 BV / hour. It is a range. The bed volume of the organic medium is the volume of the medium equal to the volume occupied by the resin bed. A flow rate of 1 BV / hour means that an amount of organic liquid equal to the volume occupied by the resin bed passes through the resin bed in one hour.

  [0126] As a result of the resin bed treatment, a purified acetic acid composition is obtained. The purified acetic acid composition, in one aspect, comprises less than 100 wppb iodide, such as less than 90 wppb, less than 50 wppb, or less than 25 wppb. In one aspect, the purified acetic acid composition comprises less than 100 wppb lithium, such as less than 50 wppb, less than 20 wppb, or less than 10 wppb. With respect to the range, the purified acetic acid composition can include 0-100 wppb, such as 0-50 wppb iodide; and / or 0-100 wppb, such as 1-50 wppb lithium. In other embodiments, the resin bed removes at least 25%, such as at least 50%, or at least 75% by weight of iodide from the crude acetic acid product. In one aspect, the resin bed removes at least 25%, such as at least 50%, or at least 75% by weight of lithium from the crude acetic acid product.

  [0127] Thus, in some embodiments, the product acetic acid, or one or more intermediates of the process recycle stream, is purified by one or more absorbents, adsorbents, or ion exchange resins (collectively purified in the present invention). Called resin). Acetic acid is contacted in a resin bed or protective column 200 to remove various impurities and produce the final acetic acid product.

  [0128] Impurities removed by the purified resin can include alkyl iodides. In particular, the alkyl iodide contains 1 to about 20 carbon atoms. Other impurities include various corrosive metals such as chromium, nickel, iron and the like.

  [0129] Suitable purified resins for the purposes of the present invention include giant reticulated strong acid cation exchange resins in which at least 1% of their active sites have been converted to silver or mercury form. The amount of silver or mercury associated with the resin may be 1-100% of the active site of the resin, or about 25% to about 75%, or convert at least about 50% of the active site to silver or mercury form. (US-4615806: the contents of which are fully incorporated herein by reference). Another suitable example is to remove halide from liquid carboxylic acid contaminated with halide impurities by contacting the acid of the liquid halide contaminant with a silver (I) exchanged macroreticular resin. US-51399981 concerning. Preferable examples of the purified resin include Amberlyst (registered trademark) 15 resin (Rohm and Haas), zeolite cation ion exchange substrate (see US-596273), and the like. Other suitable purification resins and methods are disclosed in US-5227524, US-5801279, US-5220058, EP-0685445, and US-6657078, the contents of which are fully incorporated herein by reference. What is being done is mentioned.

  [0130] In some embodiments, acetic acid is contacted with the purified resin at a temperature of at least about 50 ° C, or from about 60 ° C to about 100 ° C, or at a temperature of about 150 ° C or higher, depending on the type of purified resin used.

  [0131] In some embodiments, the flow rate of acetic acid through the column may be from about 0.5 to about 20 bed volumes / hour (BV / hour), where the bed volume is occupied by the resin in the bed. Defined as volume. In some embodiments, the flow rate may be about 6 to about 10 BV / hour, or about 7 to 8 BV / hour.

  [0132] In some embodiments, the column can include an anionic protective bed comprising a pyridine or pyrrolidone resin. Technical terms such as “pyridine resin”, “pyridine ring-containing polymer” and “pyridine polymer” used in the present invention are substituted or unsubstituted pyridine rings, or substituted or unsubstituted pyridine-containing polycyclic condensed rings such as quinoline rings. Refers to a polymer comprising In some embodiments, the resin may have a high degree of crosslinking, i.e., greater than 10% by weight. Substituents include those inert to methanol carbonylation process conditions, such as alkyl and alkoxy groups. Preferable examples of the insoluble pyridine ring-containing polymer include those obtained by the reaction of vinylpyridine and divinyl monomer, or the reaction of vinylpyridine and divinyl monomer-containing vinyl monomer, such as a copolymer of 4-vinylpyridine and divinylbenzene, 2- And copolymers of vinyl pyridine and divinyl benzene, copolymers of styrene, vinyl benzene, and divinyl benzene, copolymers of vinyl methyl pyridine and divinyl benzene, and copolymers of vinyl pyridine, methyl acrylate, and ethyl diacrylate (US Pat. No. 5,334,755). The disclosure is incorporated herein by reference).

  [0133] Suitable "pyrrolidone resins", "pyrrolidone ring-containing polymers", pyrrolidone polymers and the like include polymers containing substituted or unsubstituted pyrrolidone rings. Substituents include those inert to the methanol carbonylation medium, such as alkyl groups or alkoxy groups. Examples of insoluble pyrrolidone ring-containing polymers include those obtained by the reaction of vinyl pyrrolidone and divinyl monomer-containing vinyl monomers, such as copolymers of vinyl pyrrolidone and divinyl benzene. Suitable examples of pyrrolidone polymers include those disclosed in US-5466874, US-5286826, US-4786699, US-4139688, the disclosures of which are incorporated herein by reference, as well as Indianapolis, And those available from Reilley Tar and Chemical Corporation in the United States under the trade name Reillex®.

  [0134] In some embodiments, the nitrogen heterocycle-containing polymer is crosslinked at least 10%, or at least 15% or 20%, less than 50%, or 60%, or less than 75% to provide mechanical strength. Here, the “degree of crosslinking” refers to the content by weight percent of divinyl monomer or other crosslinking group.

  [0135] In some embodiments, suitable pyridine or pyrrolidone insoluble polymers include the free base form, and / or the N-oxide form, and / or the quaternized form. In some embodiments, the insoluble pyridine or pyrrolidone ring-containing polymer is in the form of beads or granules having a particle size of 0.01-2 mm, or 0.1-1 mm, or 0.25-0.7 mm, or It may be in a spherical form. Commercially available pyridine-containing polymers include Reillex-425 (Reilly Tar and Chemical Corporation), KEX-316, Kex-501, and KEX-212 (product of Koei Chemical Co., Ltd.).

  [0136] In some embodiments, the product acetic acid is discharged from the drying column 130 at or near the bottom of the column by stream 146 and contacted with one or more resins in the column containing the purified resin. The column containing the purification resin used in the present invention can be referred to as a purification column, a protective bed assembly or column, or simply a column. These terms are used interchangeably in the present invention. The purification or protective floor assembly is shown generally as 200 in FIG.

  [0137] In some embodiments, as shown in FIG. 2, the protective bed assembly 200 can include one or more processing devices, such as a column 202 and a column 204, each having an inlet end (each 206 and 210) and outlet ends (208 and 212, respectively). The inlet is separated from the outlet by internal chambers 214 and 216. Predetermined amounts of purified resin 218 and 220 are placed in the internal chamber.

  [0138] Acetic acid 146 from a process having a first concentration of impurities is a purified acetic acid stream 222 present at a second concentration that is lower than the first impurity concentration, even if impurities are present therein. Is sent through the internal chambers 214 and 216 at a temperature and flow rate sufficient to produce the resin and contact the purified resins 218 and 220. Thus, the second concentration of impurities can be zero or otherwise undetectable.

  [0139] In some embodiments, the protective floor assembly can further include heat exchangers 224 and 226 that control the temperature at which acetic acid is contacted with the purified resin. In some embodiments, columns 202 and 204 are plug flow columns that flow downward by gravity from the top to the bottom. However, devices that flow against gravity from the bottom inlet end to the top outlet end are also contemplated.

  [0140] In some embodiments, the first column 202 can include an outlet end 208 that is in direct fluid communication with the inlet end 210 of the second column 204. In some embodiments, conduits can be arranged between the various devices to make any of the plurality of columns the first processing device, followed by placing any of the remaining columns in series. can do. In some embodiments, multiple columns can be arranged in a parallel configuration.

  [0141] In some embodiments, the purified resin 218 of the first column 202 can be different from the purified resin 220 in the second column 204 and / or the temperature of the first column 202 can be The temperature of the second column 204 can be different and / or the volume of the inner chamber 214 of the first column 202 can be different from the volume of the inner chamber 216 of the second column 204.

  [0142] As shown in FIG. 3, in some embodiments, the column 400 includes an internal chamber 402 that is joined by a plurality of sides 404 that are arranged radially about a central axis 406. In some embodiments, the column 400 includes an infinite number of sides, i.e., has a circular cross section. The column 400 further includes an inlet end 408 that is in fluid communication with the outlet end 410 through the inner chamber 402 and is longitudinally spaced therefrom. In some aspects, the column 400 further includes a plurality of sampling ports 412 disposed through at least one side 404. The sampling port may be a solid sampling port, a liquid sampling port, or a combination thereof.

  [0143] As shown in FIG. 4, in some embodiments, each sampling port 412 has a sample inlet 416 disposed within the inner chamber 402 and an open position (shown in the flow control member 420). A first open flow path 414 between the first flow control member 418 operable between: a ball valve ball, for example) and a closed position (shown in the flow control member 418), and flow control The member is disposed outside the internal chamber 402 within the external environment 422. The term “open channel” refers to a channel that is dimensioned and arranged to allow both liquid and solid materials to pass through it. Therefore, the relative dimensions of the open channel must be defined relative to the average particle size of the solid or semi-solid material passing through it.

  [0144] There is fluid communication between the internal chamber 402 and the external environment 422 when the flow control member is in the open position. In some aspects, the first flow path 414 and the second flow path 424 are each in fluid communication with the external environment 422 when the corresponding flow control members (respectively 418 and 420) are in the open position. ing. When the flow control member is in the closed position, fluid communication between the internal chamber 402 and the external environment 422 is prevented.

  [0145] In some embodiments, the sampling port is between the sample inlet 416 and a second flow control member 420 operable between an open position and a closed position disposed outside the internal chamber 402. And a second flow path 424 that includes a porous member 426 disposed on the surface.

  [0146] In some embodiments, the second flow path 424 includes a portion of the first flow path 414 between the sample inlet 416 and the first flow control member 418. Thus, in some aspects, the second flow path is a “T-type” or “Y-type” branch of the first flow path, and the sample discharged through the first control member 418 is It can be recovered from the same location in the internal chamber 402 as the sample discharged through the two flow control members 420.

  [0147] In some embodiments, as shown in FIG. 3, the first flow path 414, the second flow path 424, or both are disposed between the sample inlet 416 and the external environment 422. A heat exchanger 428 is further included. In some aspects, the heat exchanger 428 can be removably attached to the portion of the flow path past the flow control member, as shown. Therefore, when the internal chamber is at the elevated temperature, the sample in the internal chamber 402 can be obtained using the heat exchanger 428 (also referred to as “sample cooler”), that is, the cooling pipe in the ice water tank.

  [0148] In some aspects, the first flow path 414 is within a first conduit 430 having a first outlet end 432 with a first valve 434 that includes a first flow control member 418. Be placed. In some aspects, the valve may be a ball valve, a gate valve, or the like. In some aspects, the first valve may prevent particulate material, such as an ion exchange resin disposed within the inner chamber 402, from blocking the valve after obtaining the sample. A severe condition ball valve with a seat flush system 436.

  [0149] In some aspects, the second flow path 424 is at least partially connected at a connection location 440 to the first conduit 430 and includes a second flow control member 420. Is disposed within a second conduit 438 having a second outlet end 442 with a second valve 444. In some aspects, the porous member 426 is disposed at or near the connection location 440, at or near the second outlet end 442, or a combination thereof. In some embodiments, the porous member comprises a screen, a porous frit, a filter element, or a combination thereof, generally designated as 446. In some embodiments, when multiple porous members are used, the exclusion size of the member can be varied. For example, in some embodiments, depending on the relative dimensions of the particulate material (eg, purified resin) contained within the interior chamber 402, the screen or filter element 446 of the porous member 426 is 100 mesh in the first position. The screen can be a 200 mesh screen at the second downstream location.

  [0150] In some embodiments, the first open flow path 414 allows both liquid 450 and solid 448 from the internal chamber 402 to pass through the first flow control member 418 in an open position from the sample inlet 416. Sized and arranged to allow flow into environment 422; second flow path 424 allows liquid 450 present in internal chamber 402 to pass from sample inlet 416 through porous member 426 and in an open position. While allowing the second flow control member 420 to flow into the external environment 422, at least a portion of the solid or semi-solid material 448 present in the internal chamber 402 causes the second flow control member 420 to flow. Dimension and arrange to eliminate flow through.

  [0151] In some embodiments, at least a portion 456 of the first flow path 414 extends through the inner chamber 402 away from the inner surface 458 of the side 404 through which the sampling port 412 is disposed. In the first conduit 430, so that the sample inlet 416 is spaced from the side 404 and placed in the inner chamber 402.

[0152] As shown in FIG. 3, in some embodiments, the sample inlet 416 is disposed on the side 404 through which the sampling port 412 is disposed.
[0153] In some aspects, the inner chamber 402 is measured between the opposite sides 404 perpendicular to the central axis 406 and parallel to the central axis 406 between the inlet end 408 and the outlet end 406. It has an average inner diameter 452 that is less than 50% of the average length 454 of the inner chamber 402 being measured. In some aspects, the first conduit 430 includes a plurality of sample inlets 416. In some aspects, the plurality of sample inlets of a single first conduit 430 are all coplanar with the plane 460 orthogonal to the central axis 406.

  [0154] In some aspects, the sampling port 412 has an inlet end along at least a portion of the side 404 and longitudinally (along at least a portion of one or more sides parallel to the central axis). 408 to outlet end 410) are arranged at substantially equal intervals 462.

  [0155] In some embodiments, the method includes at least one according to any or a combination of the embodiments disclosed herein, wherein the inner chamber 402 includes an amount of purified resin 448 that at least partially fills the inner chamber 402. Providing a column 400 according to any or a combination of the aspects disclosed herein, preferably including a plurality of sampling ports 412. A stream 464 to be purified, such as an acetic acid stream and / or intermediate product stream having one or more impurities at a first concentration, is then purified liquid stream 466, such as a second lower than the first concentration. At a temperature and flow rate sufficient to produce a purified acetic acid stream and / or an intermediate product stream having a concentration of impurities, it is passed through the column from the inlet end 408 through the internal chamber 402 to contact the purified resin 448, and then Send through exit end 410.

[0156] In some embodiments, the purified resin 448 comprises a giant reticulated strong acid ion exchange resin, wherein at least about 1% of the active site of the resin has been converted to silver or mercury form and the temperature is at least about 50 ° C. There, the silver or mercury exchanged ion exchange resin is effective to remove at least about 90% by weight of C ₁ -C ₂₀ organic iodide acetate stream.

  [0157] In some embodiments, the purified resin 448 is disposed within the inner chamber 402 within a plurality of zones 468 and 470 (the first zone 468 being disposed between the inlet end 408 and the second zone 470). And the second zone 470 is located between the first zone 468 and the outlet end 410). In some embodiments, the purified resin in the first zone 468 is the same as the purified resin in the second zone 470. In another aspect, the purified resin in the first zone 468 is different from the purified resin in the second zone 470. In some embodiments, the purified resin in the first zone 468 is an unfunctionalized macroreticular strong acid ion exchange resin and the purified resin in the second zone 470 is at least about 1% of the active site of the resin. Includes a giant reticulated strong acid ion exchange resin that has been converted to silver or mercury form.

  [0158] In some aspects, a method according to one or more aspects disclosed herein includes a first flow control for a time sufficient to obtain a sample comprising liquid 450 and purified resin 448 from a first sampling port. Sufficient time to manipulate the member 418 from the closed position to the open position and then return the first flow control member 418 to the closed position and / or obtain a sample containing the liquid 450 from the first sampling port; The method further includes operating the second flow control member 420 from the closed position to the open position, and then returning the second flow control member 420 to the closed position.

  [0159] In some embodiments, the method can further include analyzing one or more samples to determine one or more concentrations of the one or more impurities at the corresponding sampling port. In some embodiments, the method further includes attaching a heat exchanger at the outlet of the sampling port prior to operating the valve to obtain a sample having a reduced temperature relative to the temperature of the internal chamber. be able to. In some embodiments, the method can further include providing a plurality of columns in which the outlet end of the first column is in direct fluid communication with the inlet end of the second column.

Purification column operation and monitoring:
[0160] In some embodiments, the sample obtained from the sampling port may include a sample of purified resin present in the column, a liquid sample of the acetic acid stream present in the column, or both. By arranging a plurality of sampling ports, it is possible to obtain samples at different positions in the resin bed.

[0161] A sampling port can also be placed in close proximity to the final purified acetic acid stream produced by the column.
[0162] Measurement of the level of impurities present in a sample necessarily depends on the type of sample being analyzed. Liquid samples may be analyzed by gas chromatography (GC) analysis, high pressure liquid chromatography (HPLC) analysis, which includes normal phase, reverse phase, ion exclusion, ion pair, size exclusion, ion It should be understood to include exchange and ion chromatography methods readily understood by those skilled in the art. Any form of suitable detection device can be used. In addition, the resin sample can be extracted and / or digested to allow any of various chromatographic methods and / or analyzed by wet chemical methods, atomic absorption spectrometry, and the like. Can include inductively coupled plasma (ICP) analysis, mass spectral analysis, ICP-MS, and the like. In one aspect, the resin sample can be analyzed using X-ray fluorescence as is readily understood by those skilled in the art.

  [0163] In some embodiments, the sample is halogen, or iodide (I) and / or various transition metals from Groups 3-12, or acetic acid production such as Fe, Cr, and / or Ni. Can also be analyzed for the presence of metals or groups (which may include silver and / or mercury) to which the active site of the resin has been converted.

  [0164] In some embodiments, a combination of sampling port use and analysis can be used to control column operation, including monitoring the column's ability to remove impurities, It can include diverting the column in the stream before the impurity retention or removal characteristics are depleted.

  [0165] In some embodiments, the impurity concentration of the sample can be compared to the previously determined impurity concentration value to indicate whether the purified resin is functioning or has begun to wear out. This information can be combined with the position of the sampling port to indicate the consumption of the purified resin at a position in the column corresponding to the position of the sampling port from which the sample was obtained, depending on the impurity concentration of the sample.

  [0166] In some embodiments, the resin is exhausted when it can no longer be purified to an acceptable level of acetic acid. In some embodiments, the purified resin is when the acetic acid contacted with the resin has an iodide concentration greater than 100 wt ppb, an Fe, Cr, and / or Ni concentration greater than 500 wt ppb, or a combination thereof. Is considered “depleted”.

  [0167] Further, in some embodiments, resin samples containing about 10% or more by weight of impurities are also considered exhausted for purposes of the present invention. However, it should be understood that these levels merely reflect current requirements for the product acetic acid, and any such levels can be used. Furthermore, the level used and the impurities analyzed (measured) therefor can differ from iodides and corrosive metals, depending on the flow in which the column is located.

  [0168] In some embodiments, flow through a particular column is stopped and / or preferred by indicating a depleted column defined by a final purified acetic acid sample having an impurity profile greater than an acceptable level. Can be bypassed through a simple column.

  [0169] In some embodiments, the course of impurities throughout the column can be used to determine the rate at which the column becomes depleted, and thus can be used to predict life expectancy or otherwise The use of the column during the process can be controlled. In one aspect, the flow is stopped or otherwise bypassed by determining that the spent resin is close to the end of the column but not yet in the final purified acetic acid. Thus, it is possible to exchange the resin and / or regenerate the resin.

  [0170] In some embodiments, once the flow of acetic acid through the column is stopped, the resin can be regenerated. In some embodiments, regeneration of the spent resin includes removing at least a portion of the spent resin from the column and refilling at least a portion of the column with the active purified resin. In some embodiments, at least a portion of the active resin used to repack the column includes previously depleted resin regenerated to an active purified resin. In some embodiments, at least a portion of the spent resin is regenerated into active purified resin in the column (also referred to as in-situ regeneration). Resin regeneration depends on the resin and the type of impurities to be removed. The regeneration process can include contacting the resin with a suitable solvent, reagent, or the like.

Packing resin into the column:
[0171] As shown in FIG. 5, in some embodiments, a method or process 500 includes providing a column (502) according to any or combination of the disclosed embodiments including an internal chamber. The process includes a column including one or more sampling ports (at least one sampling port includes a liquid sampling port, a solid sampling port, or both) arranged between a column inlet and a column outlet, and at least one Opening the sampling port can further be included (505).

  [0172] Next, the method or process includes delivering a sufficient amount of purified resin into the inner chamber to fill a portion of the inner chamber (504). In some embodiments, filling the column includes opening at least one sampling port. In some embodiments, the sampling port can be used to clean the resin to remove vapor from the resin and to purge the internal chamber with an inert gas, such as during resin filling.

  [0173] In some embodiments, the resin is placed in the column in dry or wet form, either by manually transferring the resin into the top of the column or by pumping the slurry into the column. can do. In some embodiments, the resin can be supplied as a slurry in a container such as a liquid containment bag, tank lorry, or tank railcar, and can be pneumatically transferred into the column. Thus, in some embodiments, the bottom outlet of the vessel containing the slurry containing the purified resin is in fluid communication with the internal chamber. Next, an amount of pressure sufficient to pneumatically transfer at least a portion of the slurry from the container into the internal chamber is applied to the container headspace (506).

  [0174] In some embodiments, after the resin is pneumatically transferred into the column by pumping or pressurizing the container, additional water or other solvent is added to the container and the transfer process is repeated to repeat the resin flow. It can be ensured that substantially everything is transferred. In some embodiments, the column and / or vessel is purged with nitrogen or other inert gas to remove oxygen before and / or during resin transfer (508).

  [0175] In some embodiments, the resin can then be backwashed (510) with a cleaning fluid, typically water or other solvent, to remove particulates, foreign matter, and manufacturing results. Washing continues for at least 60 minutes (518). This backwash water can be sent to waste or recirculated if appropriate. The wash time may be 1 hour or more at relatively high flow rates, ensuring that the resin is evenly dispersed in the column and preventing pockets in the resin. Next, pressure is applied to the top of the column using nitrogen or the like (512), and the resin is maintained by maintaining pressure until gas is ejected from the column outlet, indicating that substantially all of the cleaning liquid has been removed. The cleaning liquid can be removed from

  [0176] The resin can then be backwashed once more with acetic acid this time (514). In some embodiments, the acid backwash is performed at a relatively slow rate and uses an acid flow rate into the bottom of the column of less than 0.05 bed volume / minute or less than 0.04 bed volume / minute (516). . Backwashing can be performed until all of the vapor present in the column is replaced by the liquid. In some embodiments, at least a portion of the vapor is removed through one or more open sampling ports. In some embodiments, only a portion of the internal chamber is first filled with resin to swell the resin, which in some embodiments is greater than 40% when the resin is exchanged from water to acetic acid. It may be.

  [0177] Once the resin is backwashed, the acetic acid stream having the first impurity concentration is sufficient to produce a purified acetic acid stream having a second impurity concentration at the outlet end that is lower than the first impurity concentration. The column can be put into service by sending it from the inlet end to the outlet end at a suitable purification temperature and flow rate.

[0178] Various aspects are contemplated, as will be apparent from the drawings and specification set forth above.
E1. (A) including an internal chamber containing an active purification resin disposed between the column inlet and the column outlet, further comprising one or more sampling ports arranged between the column inlet and the column outlet, wherein at least one sampling The mouth provides a processor column that includes a liquid sampling port, a solid sampling port, or both; and (b) an acetic acid stream having a first concentration of impurities, if present, lower than the first concentration. Flowing a purified acetic acid stream having a second concentration of impurities through the column at a temperature and flow rate sufficient to produce at the column outlet;
A method involving that.

E2. The method of aspect E1, further comprising opening at least one sampling port.
E3. The method of embodiment E1 or E2, wherein the impurity comprises iodine, chromium, nickel, iron, or a combination thereof.

E4. The method of any of embodiments E1-E3, wherein the purified resin comprises a macroreticular strong acid ion exchange resin having at least about 1% active sites in silver or mercury form.
E5. The method of any of embodiments E1-E4, wherein the temperature is at least about 50 ° C.

  E6. Obtaining a sample of purified resin through at least one solid sampling port, a liquid sample of acetic acid stream present in the column through at least one liquid sampling port, or a combination thereof to determine the concentration of impurities in at least one sample The method of any of embodiments E1-E5, further comprising:

  E7. The method of aspect E6, wherein the concentration of impurities is determined using gas chromatography, high pressure liquid chromatography, atomic absorption, inductively coupled plasma spectroscopy, mass spectroscopy, X-ray fluorescence spectroscopy, or a combination thereof.

  E8. Comparing the impurity concentration value of at least one sample with the previously determined impurity concentration value, the impurity concentration of the sample indicates the consumption of the purified resin at the position in the column corresponding to the position of the sampling port from which the sample was obtained. The method of aspect E6 or E7, further comprising determining whether or not.

E9. The method of any of embodiments E1-E8, further comprising stopping the flow of acetic acid through the column.
E10. The method of any of embodiments E1-E9, wherein the flow of acetic acid is stopped before substantially all of the active purification resin present in the column is depleted.

  E11. A second column is provided that includes an internal chamber containing an active purification resin disposed between the second column inlet and the second column outlet, and an acetic acid stream having a first concentration of impurities is present. Flowing a purified acetic acid stream having a second concentration of impurities, if any, lower than the first concentration, at a temperature and flow rate sufficient to produce at the second column outlet; The method of any of aspects E1-E10, further comprising.

E12. The method of any of embodiments E1-E11, further comprising regenerating at least a portion of the spent resin and resuming the flow of acetic acid through the column to produce a purified acetic acid stream.
E13. The method of embodiment E12, wherein regeneration of the spent resin comprises removing at least a portion of the consumed resin from the column and refilling at least a portion of the column with the active purified resin.

E14. The method of embodiment E12 or E13, wherein at least a portion of the active resin used to repack the column comprises a previously depleted resin regenerated to an active purified resin.
E15. The method of any of embodiments E12-E14, wherein at least a portion of the consumed resin is regenerated into an active purified resin within the column.

E16. (A) connected by a plurality of sides arranged radially around a central axis, in fluid communication with the outlet end through the internal chamber and longitudinally spaced therefrom; Providing a processing equipment column comprising an internal chamber having;
(B) sending an amount of purified resin sufficient to fill a portion of the internal chamber into the internal chamber;
(C) flowing an aqueous wash fluid from the outlet end through the internal chamber to the inlet end at a flow rate and time sufficient to wash and / or remove particulates from the purified resin; and (d) a first concentration of impurities. Flowing an acetic acid stream having a temperature and flow rate sufficient to produce a purified acetic acid stream having a second concentration of impurities lower than the first concentration, if any, at the column outlet;
A method involving that.

  E17. The column includes one or more sampling ports arranged between the column inlet and the column outlet, the at least one sampling port including a liquid sampling port, a solid sampling port, or both, and opening at least one sampling port The method of aspect E16, further comprising:

E18. The method of embodiment E16 or E17, wherein the aqueous cleaning fluid is allowed to flow for at least 60 minutes.
E19. Any of embodiments E16-E18, further comprising, after step (c), delivering a predetermined amount of inert gas into the column inlet in an amount and pressure sufficient to obtain a flow of inert gas through the outlet end. the method of.

  E20. The method of any of embodiments E16-E19, further comprising sending a backwash flow of acetic acid into the outlet end at a flow rate and time sufficient to remove substantially all of the vapor from the internal chamber.

E21. The method of embodiment E20, wherein the back flow of acetic acid is about 0.05 bed volume / min or less and this time is about 30 min or less.
E22. Sending the purified resin into the inner chamber provides fluid communication between the inner chamber and the bottom outlet of the container containing the slurry containing the purified resin; and at least a portion of the slurry is pneumatically transferred from the container into the inner chamber. Applying a sufficient amount of pressure to the headspace of the vessel to transfer; the method of any of embodiments E16-E21.

  E23. Prior to delivering purified resin into the internal chamber, the internal chamber, the container headspace, or both are purged with a predetermined amount of inert gas so that the internal chamber and / or the headspace contains less than 1 wt% oxygen. The method of any of aspects E16-E22, further comprising:

  E24. The impurities include iodine, chromium, nickel, iron, or combinations thereof; the purified resin includes at least about 1% of a giant reticulated strong acid ion exchange resin having active sites in the form of silver or mercury; the temperature is at least about 50 The method of any one of embodiments E16 to E23, wherein the method is; or a combination thereof.

  E25. The impurities include iodine, chromium, nickel, iron, or combinations thereof; the purified resin includes at least about 1% of a giant reticulated strong acid ion exchange resin having active sites in the form of silver or mercury; the temperature is at least about 50 The method of any one of embodiments E16 to E23, wherein the method is; or a combination thereof.

  E26. The method of any of aspects E1-E15, according to any of aspects E16-E25, wherein providing a column comprising an internal chamber comprising an active purification resin disposed between the column inlet and the column outlet.

E27. In the reactor, at least one component selected from the group consisting of methanol, dimethyl ether, and methyl acetate is added to 0.1 to less than 14% by weight of water, rhodium catalyst, methyl iodide, and lithium iodide. Carbonylation in the presence to form a reaction medium comprising acetic acid;
Separating the reaction medium into a liquid recycle stream and a vapor product stream;
Separating the vapor product stream in no more than two distillation columns in the main purification series to produce a crude acid product comprising acetic acid containing lithium cations;
In the first processor, the crude acetic acid product is contacted with an acid form cation exchanger to produce an intermediate acid product; and in the second processor, the intermediate acetic acid product is converted to an acid cation. Contacting with a metal exchanged ion exchange resin having an exchange site to produce a purified stream of acetic acid;
Wherein the first processing device, the second processing device, or both are in accordance with any of aspects E1-E15.

E28. In the reactor, at least one component selected from the group consisting of methanol, dimethyl ether, and methyl acetate is added to 0.1 to less than 14% by weight of water, rhodium catalyst, methyl iodide, and lithium iodide. Carbonylation in the presence to form a reaction medium comprising acetic acid;
Separating the reaction medium into a liquid recycle stream and a vapor product stream;
Separating the vapor product stream in no more than two distillation columns in the main purification series to produce a crude acid product comprising acetic acid containing lithium cations;
In the first processor, the crude acetic acid product is contacted with a first purified resin containing an acid form of the cation exchanger to produce an intermediate acid product; and in the second processor, the intermediate The acetic acid product is contacted with a second purification resin comprising a metal exchanged ion exchange resin having an acid cation exchange site to produce a purified acetic acid stream, wherein the first treatment device, the second The processing device, or both, individually includes at least one sampling port disposed through the side of the processing device;
Through a corresponding sampling port, obtain a sample of the first purified resin, the second purified resin, a liquid sample of acetic acid stream, or a combination thereof present in the processing apparatus; and the concentration of impurities in the at least one sample Seeking
A method involving that.

  E29. The impurity concentration of at least one sample is compared with the previously determined impurity concentration value, and the purified resin is consumed at a position in the processing apparatus corresponding to the position of the sampling port from which the sample impurity concentration was obtained. The method of aspect E27 or E28, further comprising: determining whether or not

  E30. Before substantially all of the active purified resin present in the processor is consumed, the flow of acetic acid through the processor is stopped and at least a portion of the consumed resin is regenerated according to any of aspects E16-E26. And the method of any of embodiments E27-E29, further comprising resuming the flow of acetic acid stream through the processor to produce a purified acetic acid stream.

E31. The method of any of embodiments E27-E30, wherein the metal exchanged ion exchange resin comprises a strong acid exchange site occupied by at least 1% silver.
E32. The method of any of embodiments E27-E31, wherein the crude acid product comprises 10 ppm or less lithium.

E33. Separating the steam product stream,
Distilling the vapor product stream in a first distillation column and collecting a side stream to obtain a distilled acetic acid product; and distilling the distilled acetic acid product in a second distillation column to produce acetic acid And a crude acid product comprising a lithium cation;
The method of any of aspects E27 to E32.

  E34. Adding a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide to the distilled acetic acid product before distilling the distilled acetic acid product in the second distillation column; The process of any of embodiments E27-E33, wherein at least a portion of the potassium is removed by the cation exchanger in acid form.

E35. The method of any of embodiments E27-E34, wherein the crude acetic acid product is contacted with the cation exchanger at a temperature of 50 ° C. to 120 ° C.
E36. The method of any of embodiments E27-E35, wherein the intermediate acetic acid product is contacted with an ion exchange resin that has been metal exchanged at a temperature of 50 ° C. to 85 ° C .; or a combination thereof.

E37. The method of any of embodiments E27-E36, wherein the intermediate acetic acid product has a lithium ion concentration of less than 50 ppb.
E38. The method of any of embodiments E27-E37, wherein the acid form cation exchanger comprises a resin of an acid form strong acid cation exchange macroreticular, macroporous, or mesoporous resin.

E39. The method of any of embodiments E27-E38, further comprising treating the purified acetic acid product with a cation exchange resin to recover silver, mercury, palladium, or rhodium.
E40. The method of any of embodiments E27 to E39, wherein the water concentration in the reaction medium is controlled to 0.1 to 5% by weight, based on the total amount of reaction medium present.

  E41. A lithium compound selected from the group consisting of lithium acetate, lithium carboxylate, lithium carbonate, lithium hydroxide, and mixtures thereof is introduced into the reactor to provide 0.3-0.7 wt% in the reaction medium. The method of any of embodiments E27-E40, further comprising maintaining a concentration of lithium acetate.

E42. Maintaining a hydrogen iodide concentration of 0.1 to 1.3% by weight in the reaction medium;
Maintaining a rhodium catalyst concentration of 300-3000 wppm in the reaction medium;
Maintaining a water concentration of 0.1-4.1% by weight in the reaction medium;
Maintaining a methyl acetate concentration of 0.6-4.1% by weight in the reaction medium;
Or a combination thereof;
The method of aspect E41, further comprising:

  E43. The method of any of embodiments E27-E42, further comprising controlling the butyl acetate concentration in the acetic acid product to 10 wppm or less without directly removing butyl acetate from the acetic acid product.

E44. The method of embodiment E43, wherein the butyl acetate concentration is controlled by maintaining an acetaldehyde concentration of 1500 ppm or less in the reaction medium.
E45. The method of embodiment E43 or E44, wherein the butyl acetate concentration is controlled by controlling the temperature in the reactor to 150-250 ° C.

E46. The method of any of embodiments E43-E45, wherein the butyl acetate concentration is controlled by controlling the hydrogen partial pressure in the reactor to 0.3-2 atm.
E47. The method of any of embodiments E43-E45, wherein the butyl acetate concentration is controlled by controlling the rhodium catalyst concentration in the reaction medium to 100-3000 wppm.

E48. The method of any of embodiments E27 to E47, further comprising controlling the ethyl iodide concentration in the reaction medium to 750 wppm or less.
E49. The method of embodiment E48, wherein the propionic acid concentration in the product acetic acid is less than 250 wppm without directly removing the propionic acid from the product acetic acid.

E50. The process of embodiment E48 or E49, wherein the ethyl iodide in the reaction medium and the propionic acid in the acetic acid product are present in a weight ratio of 3: 1 to 1: 2.
E51. The method of any of embodiments E48 through E50, wherein the acetaldehyde and ethyl iodide are present in the reaction medium in a weight ratio of 2: 1 to 20: 1.

E52. The method of any of embodiments E48-E51, wherein the ethanol concentration in the methanol feed stream into the reactor is less than 150 wppm; or a combination thereof.
E53. Embodiment E48 wherein 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. Any method of -E52.

  [0179] While several aspects have been shown and described in detail in the drawings and the foregoing description, this should be considered illustrative and not limiting in nature, and only some aspects are shown and described. It is understood that all changes and modifications within the spirit of some embodiments are required to be protected. As used in the above description, terms such as “ideally”, “desirably”, “preferred”, “preferably”, “preferred”, “more preferable”, or “representative” The use may be more desirable or characteristic of the features so described, but may not be essential, and the manner in which it is missing is defined by the following claims. It may be intended to be within the scope of the invention. In reading the claims, the use of words such as “one”, “one”, “at least one”, or “at least part” specifically refers to the contrary in the claims. Unless indicated, it is not intended that the claims be limited to only one item. Where the words “at least part” and / or “part” are used, this matter may include part and / or whole matter, unless specifically stated to the contrary.

Claims (20)

In the reactor, at least one component selected from the group consisting of methanol, dimethyl ether, and methyl acetate is added to 0.1 to less than 14% by weight of water, rhodium catalyst, methyl iodide, and lithium iodide. Carbonylation in the presence to form a reaction medium comprising acetic acid;
Separating the reaction medium into a liquid recycle stream and a vapor product stream;
Separating the vapor product stream in no more than two distillation columns in the main purification series to produce a crude acid product comprising acetic acid containing lithium cations;
In the first processor, the crude acetic acid product is contacted with a first purified resin containing an acid form of the cation exchanger to produce an intermediate acid product; and in the second processor, the intermediate The acetic acid product is contacted with a second purification resin comprising a metal exchanged ion exchange resin having an acid cation exchange site to produce a purified acetic acid stream, wherein the first treatment device, the second The processing device, or both, individually includes at least one sampling port disposed through the side of the processing device;
Through a corresponding sampling port, obtain a sample of the first purified resin, the second purified resin, a liquid sample of acetic acid stream, or a combination thereof present in the processing apparatus; and the concentration of impurities in the at least one sample Seeking
A method involving that.   The impurity concentration of at least one sample is compared with the previously determined impurity concentration value, and the purified resin is consumed at a position in the processing apparatus corresponding to the position of the sampling port from which the sample impurity concentration was obtained. The method of claim 1, further comprising: determining whether or not   Before substantially all of the active purified resin present in the processor is depleted, the flow of acetic acid through the processor is stopped, at least a portion of the depleted resin is regenerated, and the acetic acid flow through the processor is 3. The method of claim 2, further comprising resuming the flow of water to produce a purified acetic acid stream.   The method of claim 1, wherein the crude acid product comprises 10 ppm or less lithium. Separating the steam product stream,
Distilling the vapor product stream in a first distillation column and collecting a side stream to obtain a distilled acetic acid product; and distilling the distilled acetic acid product in a second distillation column to produce acetic acid And a crude acid product comprising a lithium cation;
The method of claim 1, comprising:   Adding a potassium salt selected from the group consisting of potassium acetate, potassium carbonate, and potassium hydroxide to the distilled acetic acid product before distilling the distilled acetic acid product in the second distillation column; The method of claim 1, wherein at least a portion of the potassium is removed by the acid form cation exchanger.   The process of claim 1, wherein the crude acetic acid product is contacted with the cation exchanger at a temperature of 50C to 120C.   The method of claim 1, wherein the intermediate acetic acid product is contacted with a metal exchanged ion exchange resin at a temperature of 50 ° C. to 85 ° C .; or a combination thereof.   The method of claim 1, wherein the intermediate acetic acid product has a lithium ion concentration of less than 50 ppb.   The method of claim 1, wherein the acid form cation exchanger comprises a resin of a strong acid cation exchange macroreticular, macroporous, or mesoporous resin in acid form.   The method of claim 1, wherein the metal exchanged ion exchange resin comprises a strong acid exchange site occupied by at least 1% silver.   The method of claim 1, further comprising treating the purified acetic acid product with a cation exchange resin to recover silver, mercury, palladium, or rhodium.   The process according to claim 1, wherein the water concentration in the reaction medium is controlled to 0.1 to 5% by weight, based on the total amount of reaction medium present.   A lithium compound selected from the group consisting of lithium acetate, lithium carboxylate, lithium carbonate, lithium hydroxide, and mixtures thereof is introduced into the reactor to provide 0.3-0.7 wt% in the reaction medium. The method of claim 1, further comprising maintaining a concentration of lithium acetate. Maintaining a hydrogen iodide concentration of 0.1 to 1.3% by weight in the reaction medium;
Maintaining a rhodium catalyst concentration of 300-3000 wppm in the reaction medium;
Maintaining a water concentration of 0.1-4.1% by weight in the reaction medium;
Maintaining a methyl acetate concentration of 0.6-4.1% by weight in the reaction medium;
Or a combination thereof;
15. The method of claim 14, further comprising:   The method of claim 1, further comprising controlling the butyl acetate concentration in the acetic acid product to 10 wppm or less without directly removing butyl acetate from the acetic acid product. Maintaining an acetaldehyde concentration of 1500 ppm or less in the reaction medium;
Controlling the temperature in the reactor to 150-250 ° C;
Controlling the hydrogen partial pressure in the reactor to 0.3-2 atm;
Controlling the rhodium catalyst concentration in the reaction medium to 100-3000 wppm;
Or a combination thereof;
17. The method of claim 16, wherein the method controls butyl acetate concentration.   The method of claim 1, further comprising controlling the ethyl iodide concentration in the reaction medium to 750 wppm or less. The propionic acid concentration in the product acetic acid is less than 250 wppm without directly removing the propionic acid from the product acetic acid;
Ethyl iodide in the reaction medium and propionic acid in the acetic acid product are present in a weight ratio of 3: 1 to 1: 2.
In the reaction medium, acetaldehyde and ethyl iodide are present in a weight ratio of 2: 1 to 20: 1;
The ethanol concentration in the methanol feed stream into the reactor is less than 150 wppm;
The method of claim 18, which is alternatively a combination thereof.   Controlling the ethyl iodide concentration in the reaction medium 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. 19. The method according to 19.

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