TW201325723A - Catalyst recovery using aqueous hydrogen iodide and acetic acid - Google Patents

Abstract

Methods are provided for recovering catalyst values from liquids containing catalyst and tar by combining the liquids with one or more aqueous solutions containing acetic acid and/or hydrogen iodide.

Description

Catalyst recovery method using aqueous solution of hydrogen iodide and acetic acid

This invention relates to a process for recovering valuable catalysts from tar which is formed during the carbonylation of methyl acetate, dimethyl ether or a combination of the two to produce acetic anhydride. More specifically, the present invention relates to a process for recovering valuable materials which are generally not extractable from tar.

The carbonylation process for the production of acetic anhydride produces tar by-products. The formation of tar and its problems in the recovery of valuable catalysts are described, for example, in U.S. Patent Nos. 4,388,217 and 4,944,927, European Patent Application No. EP 0 087 870 and EP 0008 396, and PCT Application Publication No. 91/07372. One of the problems associated with the formation of tar, as disclosed in some of the above applications, is that tar can interfere with the recovery and reuse of the catalyst. An extraction method has been developed in which a catalyst is separated from a tar contained in an organic phase such as a methyl iodide solution into an aqueous phase. However, since many catalyst components are extremely costly, there is still a need to improve the efficiency of the method of separating the catalyst from the tar and thereby recovering the catalyst.

The present invention provides a method of recovering a catalyst from a liquid containing a catalyst and tar. In certain embodiments, the method comprises combining at least one aqueous solution comprising acetic acid and hydrogen iodide with methyl iodide under conditions effective to form an aqueous phase comprising acetic acid and hydrogen iodide and an organic phase comprising methyl iodide At least some of the catalyst is concentrated in the aqueous phase. The method further comprises: feeding a liquid containing the catalyst and tar to a main feed location on the vessel; feeding at least one aqueous solution containing acetic acid to at least one aqueous feed location on the vessel, Wherein the aqueous feed location is located longitudinally below the main feed location; recovering at least some of the organic phase from the organic phase recovery location of the vessel, wherein the organic phase recovery location is located longitudinally below the main feed location; and the aqueous phase from the vessel The recovery location recovers at least some of the aqueous phase, the aqueous recovery location being located longitudinally above the primary feed location. If desired, this embodiment can further comprise feeding at least one liquid stream comprising methyl iodide to at least one organic feed location on the vessel, the location being above the longitudinal direction of the main feed location.

In some embodiments, the method comprises reacting a liquid containing a catalyst and a tar with at least one aqueous solution containing acetic acid in the presence of hydrogen iodide and methyl iodide to effectively form an aqueous phase comprising acetic acid and hydrogen iodide. And a combination comprising an organic phase comprising methyl iodide, wherein at least some of the catalyst is concentrated into the aqueous phase, wherein the method further comprises: feeding the liquid containing the catalyst and the tar to a main feed location on the vessel; Flowing at least one liquid stream containing methyl iodide to at least one organic feed location on the vessel, the location being longitudinally above the main feed location; feeding at least one aqueous solution containing acetic acid to at least one of the vessels An aqueous feed location, the aqueous feed location being below the longitudinal direction of the main feed location; recovering at least some of the organic phase from the organic phase recovery location of the vessel, the location being below the longitudinal direction of the main feed location; and the water from the vessel The phase recovery location recovers at least some of the aqueous phase that is above the longitudinal direction of the main feed location. The aqueous stream fed to the vessel also contains hydrogen iodide, as needed.

In certain embodiments, the liquid comprising the catalyst and the tar further comprises methyl iodide, acetic acid, hydrogen iodide or any combination of two or more of the foregoing. In certain embodiments, the combination is carried out in the presence of elemental iodine. For example, package The catalyst and tar containing liquid may contain at least some of the elemental iodine fed to the reactor.

In certain embodiments, the at least one aqueous solution comprising acetic acid can comprise a first solution comprising hydrogen iodide but no acetic acid; and a second solution comprising acetic acid but no hydrogen iodide. In certain embodiments, the at least one aqueous solution comprising acetic acid comprises at least one single solution comprising hydrogen iodide and acetic acid.

In certain embodiments, the catalyst comprises at least one Group VIII metal. In certain embodiments, at least one Group VIII metal is rhodium.

In certain embodiments, the at least one aqueous phase recovery location is located longitudinally above the at least one organic feed location. In certain embodiments, at least one organic phase recovery location is located longitudinally below the at least one aqueous feed location. In certain embodiments, the container comprises a longitudinal upper third portion, a longitudinal intermediate third portion, and a longitudinal lower third portion, and at least one aqueous feed location is located in a third portion of the longitudinal direction of the container. In certain embodiments, at least one organic feed location is located in a third portion of the longitudinal direction of the container. In certain embodiments, the vessel comprises a column comprising at least one reciprocating plate agitator.

In certain embodiments, from 22.5% to 55% by weight of all of the materials fed to the container are acetic acid. In certain embodiments, from 0.5 to 10% by weight of all materials fed to the vessel are hydrogen iodide.

The present invention provides a method of separating a catalyst component from a tar by concentrating the catalyst component in an aqueous phase. And at least one kind of liquid containing catalyst and tar An aqueous solution containing acetic acid is combined in the presence of hydrogen iodide and methyl iodide under conditions effective to form an aqueous phase containing acetic acid and hydrogen iodide and an organic phase containing methyl iodide. As used throughout this application, "hydrogen iodide", "iodic acid", "hydroiodic acid" and "HI" shall be used synonymously. This method achieves more efficient catalyst recovery than a separate HI aqueous solution or a separate aqueous acetic acid solution. It has been found that combining HI aqueous solution and aqueous acetic acid with a liquid containing catalyst and tar alone allows acetic acid or HI to concentrate more of the catalyst into the aqueous phase. The combination of HI and aqueous acetic acid can be used as a primary extraction technique or as a subsequent extraction technique prior to extraction to recover hydrazine that cannot be extracted only by aqueous HI. As used throughout the application, percentages, parts or other descriptions of parts of a composition are by weight or composition ratio unless specifically stated otherwise.

Liquid containing or containing catalyst and tar

The liquid for carrying out the process of the present invention and referred to herein as "liquid containing catalyst and tar" or "liquid containing catalyst and tar" contains at least a catalyst and tar, and may contain many other components. Tar refers to a compound formed as a by-product during the carbonylation of methyl acetate and in the downstream process. Tars are described in, for example, U.S. Patent Nos. 4,388,217 and 4,944,927. The catalyst can be any effective catalyst that can be separated from the tar using the methods described herein. In certain embodiments, the catalyst comprises one or more Group VIII noble metals (ie, selected from the group consisting of iron, cobalt, nickel, ruthenium, rhodium, palladium, osmium, iridium, and platinum, or combinations thereof). In certain embodiments, the catalyst comprises one or more Group VIII noble metals (ie, selected from the group consisting of ruthenium, rhodium, palladium, osmium, iridium, or platinum, or combinations thereof). In certain embodiments, the Group VIII metal is selected from the group consisting of nickel, ruthenium, and iridium or And so on. In certain embodiments, the metal is a nickel compound. In certain embodiments, the metal is a ruthenium compound. In certain embodiments, the metal is a ruthenium compound. The metal may be present in any ionized or coordinated state, including, for example, in the form of a metal, salt or complex (e.g., a carbonyl complex).

The catalyst and coke will be contained in the liquid material. The liquid may have any suitable composition and the composition of the liquid will depend on the source from which it is derived. In certain embodiments, a liquid system comprising a catalyst and a tar is prepared by combining tar with one or more liquids. In certain embodiments, the tar is diluted by methyl iodide. In certain embodiments, the liquid system is derived from a methyl acetate carbonylation process. "Derivative" means that the liquid comes directly from the process or from some downstream equipment associated with the process, as described below. Some example liquid components can include methyl iodide, acetic acid, water, ethylene diacetate, acetone, acetic anhydride, methanol, or a suitable combination of two or more of the foregoing. Other components include, for example, one or more of the following: an iodine-containing compound (for example, lithium iodide) and a residual compound derived from a promoter for a carbonylation reaction (e.g., a lithium compound, a chromium compound, a nitrogen-containing compound, such as a source) From the use of amine accelerators, and phosphorus compounds, such as those derived from the use of phosphine accelerators. The invention can be used in one or more particularly difficult recycling processes for catalyst metals present in very low concentrations, such as when some catalyst metal has been removed. Thus, in certain embodiments, the amount of one or more catalytic metals in the liquid containing the catalyst and tar prior to processing is less than 10%. In certain embodiments, this amount is less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In some embodiments, the amount of one or more catalytic metals prior to processing is at least 0.001%, At least 0.01% or at least 0.05%.

Tar is also present in the liquid composition. In certain embodiments, the liquid containing the catalyst and tar contains less than 30% tar. In various embodiments, the amount of tar is less than 20%, less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In certain embodiments, the amount of tar present may be from 0.5 to 20%, from 0.5 to 10% or from 0.5 to 7.5%.

In certain embodiments, at least 50% of the total liquid composition is methyl iodide and/or acetic acid. In certain embodiments, the amount is at least 60%, at least 70%, or at least 80%. In certain embodiments, this amount is from 60 to 95%. In certain embodiments, this amount is from 70 to 90%. In certain embodiments, at least 30% of the composition is methyl iodide. In certain embodiments, the amount is at least 40%, at least 50%, or at least 60%. Some other examples of the composition include methyl iodide in an amount of 30 to 90%, 35 to 80%, 40 to 70%, 45 to 65%, and 70 to 90%. In certain embodiments, at least 20% of the composition is acetic acid. In certain embodiments, the amount is at least 25%, at least 30%, or at least 40%. Some of the compositions exemplify an amount of acetic acid of 20 to 50%, 20 to 40%, 25 to 50%, 30 to 50%, 25 to 40%, 35 to 45%, and 30 to 40%.

In addition to methyl iodide, other iodine-containing compounds are also present. As used throughout this application, "iodine-containing compound" means any compound containing at least one iodine atom. Examples include methyl iodide, elemental iodine, acetyl iodide, hydrogen iodide, and lithium iodide. In some embodiments in which lithium is present, the liquid containing the catalyst and tar contains less than 20% lithium iodide. In certain embodiments, the amount of lithium iodide Less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1% or less than 0.5%. In certain embodiments, the amount of lithium iodide present is from 0.5 to 20%, from 0.5 to 10% or from 0.5 to 7.5%.

Elemental iodine may be another iodine containing compound present in certain embodiments in terms of the advantages of the presence of elemental iodine as taught by PCT Application Publication No. WO 91/07372. In certain embodiments, the catalyst and tar to liquid contain less than 15% elemental iodine. In certain embodiments, the elemental iodine amount is less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In various embodiments, the amount of elemental iodine present may range from 0.5 to 10%, from 0.5 to 7.5% or from 0.5 to 5%.

Water can also be present. In certain embodiments, the liquid containing the catalyst and tar contains less than 20% water. In certain embodiments, the amount of water is less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In certain embodiments, the amount of water present is from 0.5 to 20%, from 0.5 to 10% or from 0.5 to 7.5%. In certain embodiments, sufficient water is present to ensure that the amount of acetic anhydride is, for example, less than 0.1%, less than 0.001%, or undetectable in the composition.

Methyl acetate may also be present. However, in certain embodiments, methyl acetate can be used as a co-solvent for methyl iodide in the aqueous and organic phases, which limits the ability of such phase separations and should be limited. In certain embodiments, the amount of methyl acetate is less than 20%, less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In certain embodiments, methyl acetate is present in an amount from 0.001 to 15%, from 0.001 to 10%, from 0.001 to 7.5%, from 0.001 to 5%, or from 0.001 to 2.5%.

Methyl acetate carbonylation by-product ethylene diacetate (EDA) may also be present. In certain embodiments, the amount of EDA is less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In certain embodiments, the EDA is present in an amount from 0.001 to 20%, from 0.001 to 10%, from 0.001 to 7.5%, from 0.001 to 5%, from 0.001 to 2.5%, or from 0.001 to 1%. A by-product acetone may also be present. In certain embodiments, the amount of acetone is less than 15%, less than 10%, less than 7.5%, less than 5%, less than 3%, less than 2%, less than 1%, or less than 0.5%. In certain embodiments, the acetone is present in an amount from 0.001 to 20%, from 0.001 to 10%, from 0.001 to 7.5%, from 0.001 to 5%, from 0.001 to 2.5%, or from 0.001 to 1%.

Any combination of the above components is also within the scope of the invention. Thus, in certain embodiments, the liquid composition contains 30 to 90% methyl iodide, 15 to 50% acetic acid, 0.001 to 10% catalytic metal, 0.5 to 20% tar, 0.5 to 5% lithium iodide, 0.5 Up to 10% elemental iodine, 0.5 to 20% water. These examples may further comprise from 0.001 to 20% methyl acetate, from 0.001 to 20% acetone and from 0.001 to 20% EDA. In another embodiment, in certain embodiments, the liquid composition contains 40 to 60% methyl iodide, 20 to 40% acetic acid, 0.001 to 1% catalytic metal, 0.5 to 7.5% tar, 0.5 to 5%. Lithium iodide, 0.5 to 10% elemental iodine, 0.5 to 5% water. These examples may further comprise from 0.001 to 2.5% methyl acetate, from 0.001 to 1% acetone and from 0.001 to 1% EDA.

In certain embodiments, the process for obtaining a catalyst-containing and tar-containing liquid comprises reacting at elevated pressure and temperature through the presence of methyl acetate, dimethyl ether or both with carbon monoxide in the presence of a catalyst and an iodine compound. Liquid phase carbonylation to prepare acetic anhydride, which will contain methyl acetate, dimethyl ether or both The feed mixture is continuously fed to the carbonylation reactor and the reaction mixture containing acetic anhydride is continuously removed. If desired, the reaction can be carried out in the presence of one or more inorganic or organic promoters such as one or more lithium compounds, chromium compounds, amine promoters or phosphine promoters, or combinations thereof. In certain embodiments of the process, feeding to the reactor system maintains reactants, catalysts, promoters, and methyl iodide in the reaction mixture. The remainder of the reactor contents include most of the acetic anhydride product and minor amounts of by-products such as ethylene diacetate and acetone. The reactor feed may optionally contain a solvent such as acetic acid in an amount of, for example, 5 to 40 weight percent in the reaction mixture. In certain embodiments, the feed gas system carbon monoxide may contain hydrogen.

In certain embodiments, the carbonylation process is designed to simultaneously produce acetic acid and acetic anhydride by incorporating water and/or methanol into the reactor feed, for example, as described in European Patent No. 0087870. In certain embodiments, the carbonylation process is used in the manufacture of ethylene diacetate or the simultaneous manufacture of ethylene diacetate and acetic anhydride, such as by methyl acetate and/or dimethyl ether and methyl iodide. A mixture of hydrogen and carbon monoxide is contacted, for example as described in Belgian Patent No. 839,321.

The carbonylation process can be carried out, for example, in a liquid or vapor discharge mode of operation. In certain embodiments of the liquid discharge system, the catalyst component (eg, catalyst, promoter, methyl iodide, and unreacted methyl acetate, dimethyl ether, or both) is recovered from the reactor effluent and Then ring. In some embodiments, a new metal catalyst and a new promoter are added to the catalyst re-ring. The new component may be added as an acetic acid solution as needed. In some embodiments, the iodine-containing compound may be (I _2), methyl iodide, lithium iodide, or at least partially supplemented by the addition of elemental iodine. In the vapor discharge system, many of the catalyst components remain in the reactor and, therefore, the risk of depletion of their own processes is significantly reduced.

Processing before the combination step

In certain embodiments, the catalyst and tar containing liquid can be obtained from a carbonylation process, such as continuously or intermittently via a mixture of compounds present in the system. This mixture can be removed from the reactor or from downstream equipment. For example, in the case of systems employing liquid product discharge from a reactor, the liquid can be removed from certain points in the catalyst recirculation loop. This mixture can then be used as a liquid containing catalyst and tar, or can be further processed to form a liquid containing catalyst and tar. In certain embodiments, the stream from the carbonylation process is reduced by, for example, evaporation, and then combined with one or more other liquids (eg, one or more liquids containing methyl iodide) as needed. In certain embodiments, the further processing comprises filtration. In certain embodiments, the further processing comprises stripping in a flasher, combining it with other liquids in a stirred stripping tar receiver similar to that disclosed in Example 12 of U.S. Patent No. 4,388,217, followed by filtration from stripping The material of the tar receiver and feeding it to the combining step. In certain embodiments, the liquid is combined with methyl iodide and then introduced into a combined step in a stripping tar receiver or other device. In certain embodiments, hydrogen iodide is also fed to the stripping tar receiver where the hydrogen iodide reacts with lithium acetate (if present in the stripping tar receiver feed) to form lithium iodide and acetic acid. And feeding water to the stripping tar receiver where the water reacts with the remaining acetic anhydride (if present in the stripping tar receiver feed) to form acetic acid. In some embodiments, the presence of HI in the receiver also stabilizes the catalyst and reduces catalyst precipitation and fouling at the receiver and under The potential of swimming on the wall of the device. In certain embodiments, the stripping tar receiver and the apparatus for performing the combining step are configured to transfer a portion of the HI and water self-combining steps for the combining step to the stripping tar receiver for use as stripping tar receiving HI and water source.

In certain embodiments, the elemental iodine is added during upstream processing, such as by combining it with a liquid containing the catalyst and tar prior to extraction, or during the extraction step. A method for combining elemental iodine can be found, for example, in PCT Application Publication No. 91/07372. Any effective amount of elemental iodine can be added to the system. In certain embodiments, the amount of elemental iodine present in the liquid containing the catalyst and tar is from 0.5 to 100 parts of I ₂ /mol metal catalyst (eg, when the metal catalyst is enthalpy) per mole [ Rh]). In certain embodiments, the elemental iodine is used in an amount to provide from 3 to 20 parts of I ₂ /mole metal catalyst.

Process combination step

The process comprises combining a liquid containing a catalyst and a tar with a specific amount of aqueous acetic acid in the presence of hydrogen iodide and methyl iodide to concentrate the valuable catalyst from the liquid containing the catalyst and tar into the aqueous phase. "Concentration" means a quantity of valuable catalyst that contains a relatively large weight of water compared to the organic phase. Ion catalytic species, such as those present in certain liquids containing catalysts and tars, are soluble in the methyl iodide conventionally used in the process of the present invention. However, when water is present, the ionic species will preferentially dissolve in the aqueous phase. It has been found that the simultaneous presence of HI and acetic acid in the aqueous phase will result in a higher concentration of catalyst in the aqueous phase than when HI or acetic acid is used alone. Without wishing to be bound by any particular theory, HI affects that the catalytic complex present in the organic phase is greater than that affected by acetic acid, in each case causing the catalytic complex to be converted to preferentially dissolved in the aqueous phase. In the middle One or more wrong ion species.

The liquid containing the catalyst and tar is combined with at least one aqueous solution containing acetic acid. In certain embodiments, the at least one aqueous solution also contains HI. In certain embodiments, a single aqueous solution containing both acetic acid and HI is combined with a liquid containing a catalyst and tar. In certain embodiments, at least two aqueous solutions are combined with a liquid comprising a catalyst and a tar. When two or more solutions containing both HI and acetic acid are used, at least some of the acetic acid and HI may optionally be combined in different solutions or combined in different amounts in a plurality of solutions. Similarly, the two or more solutions may be combined with the liquid containing the catalyst and tar at the same time or at different times or locations as desired. As described above, the liquid containing the catalyst and the tar may contain acetic acid, HI, water or a combination of two or more of the above before the combining step.

The amount of acetic acid combined with the liquid containing the catalyst and tar and the amount of HI used will vary based on various process factors, including the composition of the liquid containing the catalyst and tar, and the additional methyl iodide in combination with the liquid. The amount (if any), the order in which the components are combined, and the configuration of the device in which the combination is implemented. The amount of HI can be determined, for example, by the desired pH, the amount of HI already present in the solution containing the catalyst and tar (if present), and whether it is desired to convert the acetate ion (if present) present in the liquid to acetic acid. The amount of acetic acid should be sufficient to aid separation, but should not be present in excessive amounts that would interfere with the separation of the aqueous and organic phases. In addition, the higher amount of acetic acid in the aqueous phase increases the solubility of the tar in the aqueous phase. The solubility of the catalyst is enhanced by the addition of additional acetic acid in the aqueous phase. These conditions should be considered for equilibrium.

As stated above, the one or more aqueous solutions contain acetic acid. In some embodiments The one or more aqueous solutions contain 0.5 to 80% acetic acid. In certain embodiments, the one or more aqueous solutions contain 10 to 70% acetic acid. In certain embodiments, the one or more aqueous solutions contain 10 to 50% acetic acid. In certain embodiments, the one or more aqueous solutions contain 15 to 40% acetic acid.

In certain embodiments, the one or more aqueous solutions also contain HI. In certain embodiments, the one or more aqueous solutions contain 20 to 70% HI. In certain embodiments, the one or more aqueous solutions contain 40 to 70% HI. In certain embodiments, the one or more aqueous solutions contain 30 to 60% HI. In certain embodiments, the one or more aqueous solutions contain 0.5 to 20% HI. In certain embodiments, the one or more aqueous solutions contain 10 to 20% HI. The one or more aqueous solutions may optionally contain other components that do not unduly interfere with the process functionality. For example, the aqueous solutions may contain elemental iodine. Other components present in the composition may depend on the source of water, HI, and acetic acid, and some examples of other possible components include corrosive metals, methyl acetate, acetone, or combinations thereof. Thus, in certain embodiments, one or more aqueous solutions fed to the extractor contain (or collectively if multiple streams are used) 0.5 to 30% by weight HI, 0.5 to 60% acetic acid, 20 to 98% water, and Less than 1% elemental iodine is required. In certain embodiments, the one or more aqueous solutions contain 10 to 20% HI, 15 to 40% acetic acid, 40 to 75% water, and optionally less than 1% elemental iodine. When two or more aqueous solutions are used, they may have the same or different compositions, and the above percentages may be considered as describing the combined composition of the two or more streams as desired.

The combination step is carried out in the presence of HI and methyl iodide under conditions effective to form an aqueous phase containing acetic acid and hydrogen iodide and an organic phase containing methyl iodide. As noted above, in some embodiments, at least some of the HI may have been previously Exist in one or more of the aqueous solutions. Alternatively, HI may be present due to the presence of HI in the liquid containing the catalyst and tar or may come from two locations. Similarly, in certain embodiments, at least some of the methyl iodide is present in the liquid containing the catalyst and tar. In certain embodiments, another stream containing methyl iodide is combined with a liquid containing a catalyst and tar. In certain embodiments, methyl iodide is present in both the liquid containing the catalyst and the tar and the other stream in combination therewith. When another stream containing methyl iodide is used, the stream may optionally contain other components that do not unduly affect the process function. Some examples of other components that may be present include elemental iodine, methyl acetate, water, acetic acid, and acetone.

Since acetic acid, HI, water and methyl iodide may also be used as components of the liquid containing the catalyst and tar, the amount of such present or added components may also be regarded as the proportion or percentage of the total feed in the combination step; A ratio or percentage of the liquid containing the catalyst and tar, the aqueous stream containing one or more of HI, acetic acid or both, and any stream containing methyl iodide. In certain embodiments, the total amount of HI fed to the combining step is from 0.5 to 15% of the total feed of the combined step. In certain embodiments, the total amount of HI fed is from 0.5 to 10% or from 0.5 to 5% of the total feed of the combination step. In certain embodiments, a sufficient amount of hydrogen iodide is used to bring the pH of the aqueous phase to 2 or less, and in some embodiments, less than one.

In certain embodiments, the total amount of methyl iodide fed to the combining step is from 20 to 80% of the total feed of the combined step. In certain embodiments, the total amount of methyl iodide fed is from 30 to 70% of the total feed to the combination step. In certain embodiments, this value is 35 to 65%.

In certain embodiments, the total amount of acetic acid fed to the combination step is from 0.5 to 55% of the total feed of the combined step. In certain embodiments, the total acetic acid fed The amount is 10 to 50% or 20 to 40% of the total feed of the combination step. However, in terms of acetic acid content, several factors need to be considered. In certain embodiments, it has been found that the beneficial effect of acetic acid on the recovery of the catalyst into the aqueous phase is greatly enhanced when the feed rate is greater than 20% of the total feed of the combined step. At the same time, as described above, when increasing the total amount of acetic acid fed to the combination step, it should be balanced against factors that can interfere with the maintenance of the different phases in the solution. This increase is a function of the amount of water and methyl iodide present and can be readily determined from references describing phase separation of solutions containing acetic acid, methyl iodide, and water. An example of this is E.T. Shepelev et al., Zhurnal Prikladnoi Khimii Vol. 64, No 11, P. 2441-2443, November 1991. In addition, a higher amount of acetic acid can result in tar remaining in the resulting aqueous phase in undesired amounts. Thus, in certain embodiments, the amount of acetic acid fed to the combination step is from 22.5 to 55% of the total feed, and in some embodiments, from 25 to 40%.

In certain embodiments, the combination is carried out in a batch process, for example, in a tank, column, or other container. In certain embodiments, the combination is carried out continuously, such as in a continuous extraction vessel, such as an extraction column. The container or column may optionally be provided with internals that permit mixing, such as baffles, trays, or the like. Agitating mechanisms such as one or more impellers, one or more reciprocating agitators, or both may also be utilized. In certain embodiments, the vessel is equipped with a column of at least one reciprocating agitator containing a plate. In certain embodiments, the column is a Karr Reciprocating Plate Extraction Column.

The combination is carried out under conditions effective to form an aqueous phase containing acetic acid and hydrogen iodide and an organic phase containing methyl iodide, at least some of which are concentrated In the water phase. Any valid condition can be used. In certain embodiments, the combination is in a vessel, for example, in a decanter that allows for vertical separation of different phases, or in a column, such as a tower that allows two or more streams to flow in a substantially convective manner. Performed in the column. By "substantially convective" is meant that the overall flow of the two or more streams is observed in the opposite direction due to the feed and discharge points but in the different directions of the localized regions of the flow. In certain embodiments, the liquid system containing the catalyst and tar is moved in a substantially convective manner to the aqueous stream, the stream containing methyl iodide, or both. In certain embodiments, the catalyst and tar containing liquid is fed to the column wherein both the aqueous stream and the stream containing methyl iodide are fed in a substantially convective manner. The position is determined in part by the relative density of each feed and the resulting stream. For example, in some embodiments in which the obtained aqueous phase density is less than the organic phase obtained (eg, the organic phase of the major component methyl iodide), the combination can be carried out in a container, at least a portion of which is one or more The aqueous solution is fed at a position vertically below the feed position of the liquid containing the catalyst and the tar, and the obtained aqueous phase is removed from the position above the feed position containing the catalyst and tar and the obtained organic phase is obtained. It is removed from the position of the feed position of the liquid containing the catalyst and tar vertically downward. These locations are also determined, in part, by the desired degree of convective flow, the design of the container and any container internals, and the overall flow rate of each flow.

In various embodiments, the feeding position of at least a portion of the one or more aqueous solutions may be within 80% of the longitudinal direction of the container, within 60% of the longitudinal direction, within one-half of the longitudinal direction, within 40% of the longitudinal direction, and below the longitudinal direction. Within one third, within 30% of the longitudinal direction or within 10% of the longitudinal direction. In certain embodiments, another organic stream is added. Adding organic streams containing methyl iodide to some In embodiments in which the obtained aqueous phase density is less than the obtained organic phase, at least a portion of the organic flow is within one-half of the longitudinal direction of the container, within 40% of the longitudinal direction, within one third of the longitudinal direction, and longitudinally. Add within 30% of the top, 20% of the top and 10% of the top.

Similarly, in various embodiments, the position at which at least a portion of the organic phase is removed from the container may be within 60% of the longitudinal direction of the container, within one-half of the longitudinal direction, within 40% of the longitudinal direction, and below the longitudinal direction. One inside, 30% inside the longitudinal direction, 20% in the longitudinal direction or 10% in the longitudinal direction. Similarly, in various embodiments, the position at which at least a portion of the aqueous phase is removed from the container may be within 60% of the longitudinal direction of the container, within one-half of the longitudinal direction, within 40% of the longitudinal direction, and above the longitudinal direction. Within 10% of the inner, longitudinal, or 20% of the longitudinal direction or 10% of the longitudinal direction.

The container layout can also be described as a percentage of the total height between different addition points of the container. In certain embodiments, the distance between the addition locations of the one or more aqueous streams is at least 10% of the height of the vessel below the point of addition of the catalyst and tar containing liquid. In other embodiments, the distance is at least 20%, at least 30%, at least 40%, at least 50%, or at least 60% of the height below the feed point of the liquid containing the catalyst and tar. Similarly, in some embodiments, the distance between the points of addition of the organic stream is at least 10% of the height of the container above the point of addition of the liquid containing the catalyst and tar. In other embodiments, this value is at least 20%, at least 30%, at least 40%, at least 50%, or at least 60% of the height above the feed point of the liquid containing the catalyst and tar.

The liquid containing the catalyst and tar can be fed at any point above the aqueous feed point (the main feed point), and if the feed contains the organic phase of methyl iodide, then Below the organic feed point.

In embodiments in which the obtained organic phase density is less than the aqueous phase, the positions described in the above three paragraphs can be inverted. That is, the main feed location of the liquid containing the catalyst and tar is below one or more aqueous feed locations and one or more organic phase recovery locations, and at one or more organic feed locations and one or more The water phase is recovered above the location. Similarly, in these embodiments, the position described above in the "one third of the longitudinal direction" may be within "the lower third of the longitudinal direction", and is described as "the height of the container above" at another position. Within 20%", it can be "within 20% of the height of the container below the other position". As used throughout this application, the description of the position of the longitudinal portion of the "upper" or "lower" side of the container means that the position is the total height of the container in the longitudinal direction from the top or bottom of the container. proportion. Therefore, the position within the "40% above" of a 100-meter-high container means no more than 40 meters from the top of the container, and the position in the "lower half" of the container means The bottom of the container does not exceed 50 meters. Similarly, the description in the present application for "positions above the longitudinal direction" or "lower longitudinal direction" for another position on the container simply means that it is tied to the container higher or lower than the other position. The height, regardless of whether it is "directly" above or below the other, or its alignment along the circumference or horizontal.

As noted above, in certain embodiments, the container may also be configured with a discharge location for transferring components of the container to an upstream device (e.g., a stripping tar receiver as described in U.S. Patent No. 4,388,217). The discharge can occur 20% in the longitudinal direction of the container, one third in the longitudinal direction, 40% in the longitudinal direction, 50% in the longitudinal direction, 60% in the longitudinal direction, 70% in the longitudinal direction, and 70% in the longitudinal direction. 70%, 60% below the longitudinal direction, 50% below the longitudinal direction, 40% below the longitudinal direction, one third of the longitudinal direction or 20% below the longitudinal direction. The height of the container depends on the feed configuration of the other feed or discharge locations and other equipment.

In some embodiments, several combinations are performed in a series of columns, other vessels, or other separation processes. For example, in some embodiments, the liquid containing the catalyst and tar has been subjected to an extraction process with an aqueous HI solution, and in a second step, combined with an aqueous solution of both HI and acetic acid. Thus, for example, in terms of the concentration of HI and acetic acid in the aqueous mixture, the subsequent extraction process can be similar to the primary extraction process.

The combination is carried out in the presence of elemental iodine, as needed. As described above, elemental iodine may be present in the liquid containing the catalyst and tar due to upstream processing. It is combined with the liquid containing the catalyst and tar during the combining step, or may be derived from a combination of the above.

Subsequent processing

As described above, the combining step results in the formation of an aqueous phase in which the catalyst has been concentrated. The catalyst is then reused in the carbonylation process. Prior to this carbonylation step, the aqueous phase can be further processed and then used, for example, to concentrate the catalyst and thereby reduce the amount of water, and then return to the process. This practice reduces the amount of anhydride decomposition caused by water, which can significantly affect the total anhydride yield of the process. The secondary benefit obtained by the use of acetic acid in the combination step is to replace a portion of the water with acetic acid in the aqueous stream obtained. This further reduces the requirement to separate the liquid from the catalyst by the amount of oil-reducing water (which can react with acetic anhydride).

The organic phase containing methyl iodide and tar can be separated, for example, by distillation and the methyl iodide recovered in the process can be reused in the combination step or His method is used in any aspect of the methyl acetate carbonylation process and related equipment. The viscous tar-methyl iodide residue can be further treated to remove any iodine or valuable catalyst present. Some examples of methods for such treatment include pyrolysis, self-solution precipitation, and adsorption deposited or not deposited on a solid support. The above examples are disclosed in U.S. Patent No. 4,476,237.

Instance

The invention is further illustrated by the following examples of the preferred embodiments thereof, which are to be construed as being limited by the scope of the invention. For Comparative Example A and Example B, all of the ruthenium concentrations and amounts in the examples set forth below are provided as the amount of ruthenium complex (Rh(CO) ₂ I ₂ ) ^- . For laboratory examples 1 to 38, the strontium concentration is based solely on hydrazine, not on the complex.

Comparison example A

Will contain an average concentration of 72 parts of methyl iodide, 5 parts of acetone, 244 parts of methyl acetate, 377 parts of acetic acid, 643 parts of acetic anhydride, 10 parts of ethylene diacetate (EDA), 11 parts of lithium iodide, 21 parts of lithium acetate (LiOAc), 5.3 parts of rhodium and 75 parts of tar catalyst-tar solution were processed in a flasher, filter and continuous convection fractionation column arranged in a manner similar to that described in Example 12 of U.S. Patent No. 4,388,217. The filtration flow from the stripping tar receiver to the position above the midpoint of the extractor is modeled as containing 1113 parts of methyl iodide, 1 part of acetone, 28 parts of methyl acetate, 40 parts of water, 6.6 parts of hydrazine, 503 parts. The average concentration of acetic acid, 8 parts EDA, 76 parts lithium iodide, 49 parts iodine and 95 parts tar. The flow from the midpoint of the continuous extractor and re-twisting to the stripping tar receiver is modeled as containing 182 parts of methyl iodide, 1 part of acetone, 1.2 parts of hydrazine, 4 parts of acetic acid. The average concentration of methyl ester, 88 parts water, 91 parts acetic acid, 1 part EDA, 20 parts lithium iodide, 13 parts HI, 15 parts iodine and 20 parts tar. The methyl iodide stream fed to the upper portion (above the feed point of the stripping tar receiver) contained an average concentration of 240 parts methyl iodide, 0.2 parts methyl acetate and 0.3 parts water. An aqueous HI solution containing 375 parts water, 58 parts HI, and 1 part iodine was fed to the lower portion of the extractor (below the feed point of the stripping tar receiver).

The overhead stream comprising primarily the aqueous phase containing acetic acid and most of the valuable catalyst and the underflow stream comprising primarily the organic methyl iodide phase containing tar are each continuously removed from the extractor. The overhead stream contained an average concentration of 215 parts of methyl iodide, 14 parts of methyl acetate, 379 parts of water, 438 parts of acetic acid, 55 parts of lithium iodide, 58 parts of HI, 5.3 parts of Rh, and 31 parts of iodine. The extractor bottoms stream contained an average concentration of 802 parts of methyl iodide, 3 parts of methyl acetate, 7 parts of EDA, 6 parts of iodine, 0.2 parts of Rh, and 74 parts of tar.

The enthalpy extraction efficiency of this system can be described as the sum of the enthalpy in the bottoms stream divided by the sum of the bottoms stream and the top stream (ie, the total output of the system). This amount is 5.3 ÷ (5.3 + 0.2) = 0.96 or 96%.

Instance B

The operation is similar to the process of Comparative Example 1. The catalyst-tar solution contains 52 parts of methyl iodide, 2 parts of acetone, 219 parts of methyl acetate, 335 parts of acetic acid, 647 parts of Ac ₂ O, 3 parts of EDA, 11 parts of lithium iodide, 22 parts of lithium acetate, 4.3 parts of Rh And 73 parts of tar. The filtered stream from the stripping tar receiver to the extraction column contains 990 parts methyl iodide, 1 part acetone, 25 parts methyl acetate, 148 parts water, 435 parts acetic acid, 4 parts EDA, 68 parts lithium iodide The average concentration of 45 parts of elemental iodine, 91 parts of tar and 6.3 parts of Rh. A stream containing 239 parts of methyl iodide, 1 part of methyl acetate and 0.2 parts of water was fed to the upper part of the extractor. The stream obtained from the midpoint of the continuous extractor was modeled to contain 84 parts of methyl iodide, 3 parts of methyl acetate, 197 parts of water, 20 parts of acetic acid, 1 part of EDA, 20 parts of lithium iodide, and 11 parts of HI (100%). The average concentration of hydrogen iodide), 13 parts of iodine and 18 minutes of tar. An aqueous solution containing an average concentration of 252 parts of water, 123 parts of acetic acid, 57 parts of HI, and 1 part of iodine was fed to the lower portion of the extractor.

The top stream of the extractor contained 361 parts of methyl iodide, 220 parts of water, 686 parts of acetic acid, 68 parts of lithium iodide, 71 parts of HI, 30 parts of iodine, 13 parts of tar, and 5.1 parts of Rh. The extractor bottoms stream contains 694 parts of methyl iodide, 1 part of methyl acetate, 10 parts of acetic acid, 4 parts of EDA, 0.1 part of Rh, 1 part of iodine and 47 parts of tar.

The extraction efficiency of this system was 5.1 ÷ (5.1 + 0.1) = 0.98 or 98%.

Laboratory extraction: Examples 1 to 38 Examples 1 to 17

A non-aqueous (methyl iodide) bottoms stream was obtained from an extraction process similar to that described in Comparative Example A. The tar stream obtained from the bottom of the organic phase column contained 91.9% methyl iodide, 6.8% tar, 52 ppm Rh, 0.5% I ₂ , 0.4% methyl acetate, 0.1% EDA and 0.04% acetic acid.

This tar stream (40 ml) was subjected to four batches of extraction by a mixture of HI, acetic acid and water (40 ml each). The mixture was shaken in a separatory funnel for two minutes and the layers were separated for at least two minutes. The bottom layer is contacted with a new aqueous mixture for subsequent extraction. This process was repeated to perform a total of four extractions of the bottom (organic) layer. A portion (5 ml) of the bottom layer was collected and sampled only after the first extraction. Analyze the radon concentration and tar concentration of the sample.

The mass balance in the 17 experiments was in the range of 97.6 to 98.5%. Yu Yu The amount is in the range of 65 to 108%. The tar quality margin is in the range of 66 to 86%. The ruthenium extraction is calculated as the cumulative amount of ruthenium measured in the aqueous layer compared to the amount of ruthenium measured in the tar stream at the beginning. The tar extraction in the aqueous stream was calculated in the same manner. The 17 experimental lines were designed to measure the effects of HI, acetic acid and water concentrations on hydrazine extraction and tar extraction. The HI concentration varies from 5 to 20%. The concentration of acetic acid varies from 0 to 60%. The water concentration varies from 20 to 95%. The hydrazine extraction is in the range of 6 to 72%. The tar extraction is in the range of 1 to 27%.

Table 1A lists the compositions of the aqueous streams used in these examples alone. Table 1B lists the composition of the total combined aqueous organic phase of each extraction and the enthalpy and tar extraction efficiency. The weight percentages in Table 1B were adjusted to show a 3% tar solution concentration and a 63% methyl iodine concentration.

The data show that acetic acid increases the strontium extraction regardless of the HI concentration. The same applies to tar extraction, but to a lesser extent. Comparative Examples 1 and 2 and Examples 3 and 5, Examples 8 and 9, Example 10 and Example 11, and Examples 12 and 13 and Examples 14 and 17 demonstrate the benefits of acetic acid.

Examples 18 to 29

Different but similar experiments used a tar stream obtained from two enthalpy extraction column processes that were continually operated from tar. Each extraction process was operated in a manner similar to that described in Comparative Example A above, but with the exception that the bottom stream of the organic phase from the first extraction process was fed to the previously stirred tank and then fed to the second extraction. No other material is fed to the stirred tank, so the feed to the second extraction stage feed has the same composition as the bottoms stream from the first column extraction. The feed system of the HI and methyl iodide aqueous solution to the second extraction is the same as the first time. The bottom stream of the second column has a composition of 94.0% methyl iodide, 5.0% tar, 27 ppm Rh, 0.5% I ₂ , 0.1% methyl acetate and 0.1% EDA.

This bottoms stream (30 ml) was subjected to four batches of extraction by a mixture of HI, acetic acid and water (40 ml each). The mixture was shaken in a separatory funnel for two minutes and the layers were separated for at least two minutes. The bottom layer is contacted with a new aqueous mixture for subsequent extraction. This process was repeated to perform a total of four extractions of the bottom (organic) layer. Collect each top layer and sample. Analyze the radon concentration and tar concentration of the sample.

The mass balance in the 12 experiments ranged from 96.3 to 98.6%. The mass balance is in the range of 64 to 137%. The tar mass balance is in the range of 61 to 90%. The ruthenium extraction is calculated as the cumulative amount of ruthenium recovered in the aqueous layer compared to the amount of ruthenium present in the tar stream. Extraction of tar into the aqueous stream is calculated in the same manner. The 12 experimental lines were designed to measure the effects of HI, acetic acid and water concentrations on hydrazine extraction and tar extraction. The HI concentration varies from 5 to 20%. The acetic acid concentration varies from 0 to 70%. The water concentration varies from 10 to 95%. The hydrazine extraction is in the range of 0 to 105%. The tar extraction is in the range of 2 to 49%.

Table 2A lists the composition of the aqueous streams used in these examples alone. Table 2B lists the composition of the total combined aqueous-organic phase and the enthalpy and tar extraction efficiency for each extraction. The weight percentages in Table 2B were adjusted to show a 3% tar solution concentration and a 57% methyl iodine concentration.

The data confirms that the addition of acetic acid increases the hydrazine extraction regardless of the HI concentration, even though the tar has been processed by two continuous extractors with HI feed. Also. The same applies to tar extraction, but to a lesser extent. Comparison of Examples 18 to 22 confirmed that when the HI concentration was low (5% in Table 2A; 2% in Table 2B), high concentration of acetic acid (70% in Table 2A; 28% in Table 2B) was favorable. . Comparison of Examples 26 to 30 confirmed that when the HI concentration was high (20% in Table 2A; 8% in Table 2B), acetic acid remained favorable only at high concentrations but decreased in critical value (especially 35 in Table 2A). % and higher, 14% and higher in Table 2B).

Comparative Example 18 and Example 26 demonstrate that for such streams that have been previously extracted by two HIs, when acetic acid is absent, the hydrazine is substantially non-extractable regardless of the HI concentration. Comparative Example 20 and Example 28 and Example 22 and Example 23 demonstrate that HI is beneficial when acetic acid is present. The HI concentration only has an effect on tar extraction at very high acetic acid concentrations.

High acetic acid concentrations result in a decrease in the quality of the organic layer. There was no significant effect before the acetic acid concentration was as high as 35% (Table 2A), but when the acetic acid concentration was above 35% (Table 2A), the mass of the organic layer was significantly reduced after four extractions.

Figure 1 graphically shows this data and shows the importance of HI and acetic acid concentration. As shown, increasing the acetic acid concentration (x-axis) increases the enthalpy extraction efficiency (y-axis). However, this increase is more pronounced with increasing acetic acid concentration and higher HI concentration (square data points) at lower acetic acid concentrations than for lower HI concentrations (diamond data points). This sharp increase can be readily appreciated by comparing Table 2B data for all samples with 8% HI (Examples 26 through 29) or comparing all samples with 6% HI (Examples 24 through 25).

Examples 30 to 38

The stream collected from the methyl acetate carbonylation reactor is at 95 ° C and 7 torr Distilled under pressure. The concentrated sample was diluted with acetic acid and methyl iodide to contain 78.7% methyl iodide, 15.6% acetic acid, 5.6% tar, and 713 ppm Rh.

This tar stream (100 g) was subjected to up to four batches of extraction by a mixture of HI, acetic acid and water (100 g each). The mixture was shaken in a separatory funnel for two minutes and the layers were separated for at least two minutes. Collect the bottom layer. Collect the top layer and sample. The bottom layer was returned to the separatory funnel for the next partial extraction with the same new extractant. A portion (5 ml) of the bottom layer was collected and sampled after each extraction and the amount of extractant adjusted accordingly. Analyze the radon concentration and tar concentration of the sample.

The mass balance in the nine experiments ranged from 95.9 to 98.1%. The remaining amount is in the range of 45 to 96%. The tar balance is in the range of 30 to 44%. The ruthenium extraction is calculated as the cumulative amount of ruthenium recovered in the aqueous layer compared to the amount of ruthenium present in the tar stream. The tar extraction is calculated in the same manner. The nine experimental lines were designed to measure the effects of HI, acetic acid and water concentrations on hydrazine extraction and tar extraction. The HI concentration varies from 0 to 15%. The acetic acid concentration varies from 0 to 75%. The water concentration varies from 25 to 100%. The hydrazine extraction is in the range of 13 to 96%. The tar extraction after the first extraction is in the range of 2 to 11%. The tar extraction after the first extraction was not measured.

Table 3A lists the compositions of the aqueous streams used in these examples alone. Table 3B lists the composition of the total combined aqueous and organic phases of each extraction and the enthalpy and tar extraction efficiency. The weight percentages in Table 3B were adjusted to show a 3% tar solution concentration and a 39% methyl iodine concentration. All samples were based on a series of four extractions, but are additionally illustrated in Table 3B.

The data shows that the addition of acetic acid to HI increases the extraction of hydrazine regardless of the HI concentration. The same applies to tar extraction, but to a lesser extent. Examples 30 to 32 were compared to each other and Examples 33 to 38 were compared to each other to confirm the benefit of acetic acid. Comparative Example 30 and Example 33, Example 31 and Example 35, and Example 32 and Example 37 confirm The benefit of HI. Combining HI with acetic acid in an aqueous stream is extremely advantageous for hydrazine extraction.

Figure 2 graphically presents the data in Table 3B and again shows the individual effects of HI and acetic acid concentration. As shown, increasing the acetic acid concentration (x-axis) increases the extraction efficiency of y- for both samples without HI (diamond data points) and samples with 8% HI (square data points) (y- axis). As shown, the extraction efficiency at 84% acetic acid concentration and no HI was 84%, while the same extraction efficiency was obtained at 8% acetic acid and 8% HI (compare Examples 30 and 37 in Table 3B). It is worth noting that the extraction of Example 38 (45% acetic acid concentration) resulted in the miscibility of the aqueous and organic phases to the extent that sufficient organic phase could not be retained after three extractions and had the highest undesired tar concentration in the aqueous phase. . These results demonstrate the benefit of using both low concentrations of HI and acetic acid (rather than higher acetic acid concentrations) for efficient hydrazine extraction and pumping excess tar into the recovered aqueous phase.

The present invention has been described in detail with reference to the preferred embodiments thereof, and it is understood that changes and modifications may be made within the spirit and scope of the invention.

Figure 1 is a graph showing the extraction efficiency of ruthenium obtained using an aqueous solution having different concentrations of acetic acid and hydrogen iodide. The data is presented in Table 2B. The acetic acid concentration of the composition is shown on the x-axis. The extraction efficiency of ruthenium is shown on the y-axis. The diamond data points represent a solution having a hydrogen iodide concentration of 2%. The square data points represent solutions having a hydrogen iodide concentration greater than 4%.

Figure 2 is a graph showing the percentage of catalyst extraction obtained in a laboratory separation of a liquid containing a catalyst and tar. The data is presented in Table 3B. The x-axis represents the percentage of acetic acid in the total composition. The extraction efficiency of ruthenium is shown on the y-axis. The square data points show the percent extraction efficiency at which the composition contains 8% hydrogen iodide extracted from the amount of acetic acid shown on the x-axis. The diamond data points show the percent extraction at a hydrogen iodide concentration of 0%.

Claims (23)

A method for recovering a catalyst from a liquid containing a catalyst and a tar, the method comprising: reacting a liquid comprising a catalyst and a tar with at least one aqueous solution comprising acetic acid, hydrogen iodide and methyl iodide to effectively form an acetic acid and iodine Combining the aqueous phase of hydrogen and the organic phase comprising methyl iodide, wherein at least some of the catalyst is concentrated into the aqueous phase, wherein the method further comprises: feeding the liquid comprising the catalyst and the tar to the Feeding at least one aqueous solution comprising hydrogen iodide and acetic acid to at least one aqueous feed location on the vessel at a primary feed location on the vessel, the aqueous feed location being below the longitudinal direction of the primary feed location Retrieving at least some of the organic phase from the organic phase recovery location of the vessel, the organic phase recovery location being vertically below the primary feed location, and recovering at least some of the aqueous phase from the aqueous phase recovery location of the vessel, The aqueous recovery location is above the longitudinal direction of the main feed location. The method of claim 1, wherein the method further comprises feeding at least one liquid stream comprising methyl iodide to at least one organic feed location on the vessel, the at least one organic feed location being at the primary feed location Vertically above. A method for recovering a catalyst from a liquid containing a catalyst and a tar, the method comprising: reacting the liquid containing the catalyst and the tar with at least one aqueous solution containing acetic acid in the presence of hydrogen iodide and methyl iodide, thereby effectively forming Under the condition of an aqueous phase containing acetic acid and hydrogen iodide and an organic phase containing methyl iodide a combination, wherein at least some of the catalyst is concentrated into the aqueous phase, wherein the method further comprises: feeding the catalyst-containing and tar-containing liquid to a main feed location on the vessel, at least one comprising methyl iodide The liquid stream is fed to at least one organic feed location on the vessel, the at least one organic feed location being longitudinally above the primary feed location, and the at least one aqueous solution comprising acetic acid is fed to the vessel at least An aqueous feed location, the aqueous feed location being vertically below the main feed location, at least some of the organic phase being recovered from the organic phase recovery location of the vessel, the organic phase recovery location being at the primary feed location Downstream of the longitudinal direction, and recovering at least some of the aqueous phase from the aqueous phase recovery location of the vessel, the aqueous phase recovery location being longitudinally above the primary feed location. The method of claim 3, wherein the aqueous stream further comprises hydrogen iodide. The method of any one of claims 1 to 4, wherein the liquid comprising the catalyst and the tar previously further comprises methyl iodide. The method of claim 5, wherein the liquid comprising the catalyst and the tar previously further comprises hydrogen iodide. The method of claim 5, wherein the liquid comprising the catalyst and the tar previously further comprises acetic acid. The method of claim 5, wherein the liquid comprising the catalyst and the tar previously further comprises hydrogen iodide and acetic acid. The method of any one of claims 1 to 4, wherein the catalyst and the tar are included The liquid previously further contains acetic acid. The method of claim 8, wherein the liquid comprising the catalyst and the tar previously further comprises hydrogen iodide. The method of any one of claims 1 to 4, wherein the combination is carried out in the presence of elemental iodine. The method of claim 11, wherein the liquid comprising the catalyst and the tar comprises at least some of the elemental iodine. The method of any one of claims 1 to 4, wherein the at least one aqueous solution comprising acetic acid comprises at least: a first solution comprising hydrogen iodide but no acetic acid; and a second solution comprising acetic acid but no iodine Hydrogen. The method of any one of claims 1 to 4, wherein the at least one aqueous solution comprising acetic acid comprises at least one single solution comprising hydrogen iodide and acetic acid. The method of any one of claims 1 to 4, wherein the catalyst comprises at least one Group VIII metal. The method of claim 15 wherein at least one of the Group VIII metals is rhodium. The method of any one of claims 1 to 4, wherein the at least one aqueous phase recovery location is located longitudinally above the at least one organic feed location. The method of any one of claims 1 to 4, wherein the at least one organic phase recovery location is located vertically below the at least one aqueous feed location. The method of any one of claims 1 to 4, wherein the container comprises one third of the longitudinal direction, one third of the longitudinal direction, and one third of the longitudinal direction, and the at least one aqueous feed position is located in the container Within one third of the longitudinal direction. The method of claim 3 or 4, wherein the container comprises one third of the longitudinal direction, one third of the longitudinal direction, and one third of the longitudinal direction, and the at least one organic feed position is located above the longitudinal direction of the container Within one third. The method of any one of claims 1 to 4, wherein the vessel comprises a column comprising at least one reciprocating plate agitator. The method of any one of claims 1 to 4, wherein from 22.5% to 55% by weight of all of the materials fed to the container are acetic acid. The method of any one of claims 1 to 4, wherein 0.5 to 10% by weight of all materials fed to the container are hydrogen iodide.