Process for purifying organic amines

Abstract

The present invention relates to a process for purifying an organic amine, the process comprising: (a) providing an organic amine having a normal boiling point at 1 bar in a first vessel (5), (b) charging the first vessel (5) with an inert gas, (c) heating the organic amine in the first vessel (5) to a sub-boiling temperature, the sub-boiling temperature being at least 15° C. below the normal boiling point, (d) cooling vapors from the first vessel (5) in a second vessel (20) to provide a liquid, and (e) contacting the organic amine with a resin polymer matrix, in which an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof is embedded.

Description

[Technical Field]

[0001] The present invention relates to a process for purifying organic amines by removing metal contaminants and other impurities.

[0002] Introduction Organic amines are good ligands for metal ions, and therefore, metal impurities are a common problem when producing organic amines. In electronic applications, metal and other contaminants can be a major root cause of electronic device failure. Process chemicals must contain extremely low concentrations of impurities such as metals. Based on prior art and industrial experience, single or multiple purification processes are essential to purify chemicals to achieve electronic grade standards. The associated equipment configurations are complex and difficult to use. The present invention claims a purification process that is easy to implement and allows for the production of pure organic amines.

[0003] It would be desirable to have a purification process that is easy to perform and that facilitates the production of highly pure organic amines. Summary of the Invention

[0004] The present invention relates to a process for purifying organic amines. In various embodiments, the present invention can purify organic amines to very low levels of metal ions and other contaminants. In some embodiments, the present invention advantageously provides a process for purifying organic amines that is easier to perform than conventional approaches.

[0005] In one embodiment, a process for purifying an organic amine includes: (a) providing an organic amine having a normal boiling point at 1 bar to a first vessel; (b) filling the first vessel with an inert gas; (c) heating the organic amine in the first vessel to a sub-boiling temperature, the sub-boiling temperature being at least 15° C. below the normal boiling point; (d) cooling vapors from the first vessel in a second vessel to provide a liquid; and (e) contacting the organic amine with a resin polymer matrix, wherein an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof is embedded in the resin polymer matrix. It should be noted that the present specification discloses the following aspects. [Aspect 1] 1. A process for purifying an organic amine, comprising: (a) providing the organic amine having a normal boiling point at 1 bar in a first vessel; (b) filling the first container with an inert gas; (c) heating the organic amine in the first vessel to a sub-boiling temperature, the sub-boiling temperature being at least 15° C. below the normal boiling point; (d) cooling the vapor from the first vessel in a second vessel to provide a liquid; and (e) contacting the organic amine with a resin polymer matrix, wherein the resin polymer matrix is ​​embedded with an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof. The process includes: [Aspect 2] 2. The process of embodiment 1, wherein steps (c) and (d) occur before step (e), and wherein the organic amine in step (e) is the liquid from step (d). [Aspect 3] 2. The process of aspect 1, wherein step (e) occurs before steps (a) through (d), and wherein the organic amine is provided to the first vessel in step (a) after contacting the resin polymer matrix. [Aspect 4] Aspect 4. The process of any one of aspects 1-3, wherein a minimum sub-boiling temperature is 160°C lower than the normal boiling point of the organic amine when the normal boiling point is at least 200°C; 120°C lower than the normal boiling point of the organic amine when the normal boiling point is between 150°C and 200°C; and greater than 25°C when the normal boiling point of the organic amine is less than 150°C. [Aspect 5] Aspect 5. The process of any one of aspects 1-4, wherein after the process steps are completed, the concentrations of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the organic amine are each 10 ppb or less. [Aspect 6] Aspect 6. The process of any one of aspects 1-5, wherein the water content and oxygen content in the first vessel are each less than 20 ppm. [Aspect 7] Aspect 7. The process of any one of aspects 1 to 6, wherein the resin polymer matrix comprises polyacrylate or polystyrene-divinylbenzene. [Aspect 8] Aspect 8. The process of any one of aspects 1 to 7, wherein the pore size of the resin polymer matrix is ​​in the range of 1 to 2,000 nm as determined by specific surface area of ​​the solid by gas adsorption. [Aspect 9] 9. The process of any one of aspects 1 to 8, wherein the resin polymer matrix is ​​introduced into the liquid containing the organic amine as resin beads, the beads having a size ranging from 100 to 2000 μm. [Aspect 10] 10. The process of any one of aspects 1-9, wherein the organic amine comprises highly concentrated monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, dimethylethanolamine, N-methyldiethanolamine, or aminoethyleneethanolamine.

[0006] Various embodiments of the invention are described in more detail in the detailed description that follows. [Brief explanation of the drawings]

[0007] [Figure 1] FIG. 1 is a flow diagram illustrating a process for purifying an organic amine according to one embodiment of the present invention. DETAILED DESCRIPTION OF THE INVENTION

[0008] As used throughout this specification, the following abbreviations have the following meanings, unless the context clearly dictates otherwise: BV / hr = bed volume / hour; μm = micrometer, nm = nanometer, g = gram, mg = milligram, L = liter, mL = milliliter, ppm = parts per million, ppb = parts per billion, ppt = parts per trillion, m = meters, mm = millimeters, cm = centimeters, min = minutes, s = seconds, hr = hour, °C = degree Celsius, % = percent, vol% = volume percent, wt% = weight percent.

[0009] Generally, the present invention relates to processes for purifying organic amines. Organic amines that can be purified using these processes include, but are not limited to, highly concentrated (containing less than 1% by weight, preferably less than 0.1% water) N-methylethanolamine or similar chemical structures such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, and aminoethyleneethanolamine. Near-pure amines may also be mixed together. In some embodiments, the viscosity of the organic amine to be purified ranges from 10 cP to 100 cP (as measured by ASTM D7042) and the pH value of a 0.1 mol / L aqueous solution ranges from 10 to 13 (as measured by ASTM E70). An important characteristic in characterizing organic amines for use in the processes of the present invention is their normal boiling point. As used herein, "normal boiling point" refers to the boiling point of the organic amine measured at 1 bar.

[0010] In one aspect, a process for purifying an organic amine (described herein) includes: (a) providing an organic amine having a normal boiling point at 1 bar to a first vessel; (b) filling the first vessel with an inert gas; (c) heating the organic amine in the first vessel to a sub-boiling temperature, the sub-boiling temperature being at least 15°C below the normal boiling point; (d) cooling vapor from the first vessel in a second vessel to provide a liquid; and (e) contacting the organic amine with a resin polymer matrix, wherein an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof is embedded in the resin polymer matrix. In some embodiments, steps (c) and (d) are performed before step (e), and the organic amine in step (e) is the liquid from step (d). In other words, in such embodiments, sub-boiling separation is performed before contacting with the resin polymer matrix. In other embodiments, step (e) occurs before steps (a) through (d), and the organic amine is provided to the first vessel in step (a) after contacting the resin polymer matrix. In other words, in such embodiments, contacting the resin polymer matrix occurs before subboiling separation.

[0011] In some embodiments, after the process steps are completed, the concentrations of Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn in the organic amine are each 10 ppb or less. In some embodiments, the total metal content (Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn) in the organic amine prior to the process of the present invention is a maximum of 5 ppm. In some embodiments, after the process steps are completed, the total metal content (Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn) in the organic amine is 20 ppb or less.

[0012] In some embodiments, the moisture content and oxygen content in the first container are each less than 20 ppm.

[0013] In some embodiments, the resin polymer matrix comprises polyacrylate or polystyrene-divinylbenzene. The pore size of the resin polymer matrix, in some embodiments, is in the range of 1-2,000 nm, as determined by the specific surface area of ​​the solid by gas adsorption. In some embodiments, the resin polymer matrix is ​​introduced into a liquid containing an organic amine as resin beads, the beads having a particle size in the range of 100-2000 μm.

[0014] The process of the present invention includes a subboiling step. The subboiling step involves heating the organic amine to a temperature at least 15°C below the normal boiling point of the organic amine. The minimum temperature used for the subboiling step depends on the normal boiling point and melting point of the organic amine (e.g., the subboiling temperature must clearly be higher than the temperature at which the liquid organic amine can crystallize). In some embodiments, if the normal boiling point of the organic amine is at least 200°C, the minimum subboiling temperature is 160°C below the normal boiling point. In some embodiments, if the normal boiling point of the organic amine is between 150°C and 200°C, the minimum subboiling temperature is 120°C below the normal boiling point. In some embodiments, if the normal boiling point of the organic amine is less than 150°C, the minimum subboiling temperature is greater than 25°C. In some embodiments, if the normal boiling point of the organic amine is at least 200°C, the minimum subboiling temperature is 160°C below the normal boiling point. When the normal boiling point of the organic amine is 150°C to 200°C, the minimum sub-boiling temperature is 120°C lower than the normal boiling point, and when the normal boiling point of the organic amine is less than 150°C, the minimum sub-boiling temperature is greater than 25°C.

[0015] Turning to one embodiment of the sub-boiling process, an organic amine is provided in a first vessel. The first vessel is then filled with an inert gas, such as nitrogen or argon. The purity of the inert gas is at least 99.999%. As the inert gas flows into the first vessel, it must be passed through a gas filter to remove particles and dust to maintain gas purity. Additionally, the moisture and oxygen content are controlled to less than 20 ppm using techniques known to those skilled in the art based on the teachings herein. The contents of the first vessel are then heated to a temperature not exceeding a sub-boiling temperature, which is 15°C below the normal boiling point of the organic amine. Heating the organic amine in the first vessel generates vapor. The vapor flows from the first vessel through a pipe or other conduit to a second vessel. In the second vessel, the vapor is allowed to cool and condense into a liquid. For the organic amines contemplated herein, in some embodiments, the temperature of the liquid in the second vessel must be kept below 20°C. Thus, a sub-boiling procedure, in some embodiments, includes: (a) providing an organic amine to a first vessel; (b) filling the first vessel with an inert gas; (c) heating the organic amine in the first vessel to a sub-boiling temperature, the sub-boiling temperature being at least 15° C. below the normal boiling point of the organic amine; and (d) cooling vapor from the first vessel in a second vessel to provide a liquid.

[0016] If the organic amine was not contacted with a resin polymer matrix prior to subboiling, the purified organic amine may be recovered for use. If the organic amine was not passed through a resin polymer matrix, the organic amine from the second vessel in the subboiling step may be carried forward to the resin polymer matrix procedure as further described herein.

[0017] Contacting an organic amine with a resin polymer matrix involves the use of ion exchange resins featuring iminodiacetic acid or aminomethylphosphonic acid (or both). Iminodiacetic acid HN(CH2CO2H)2, often abbreviated as IDA, is a dicarboxylic amine. The iminodiacetic acid anion functions as a tridentate ligand and can form complexes with metal ions. Aminomethylphosphonic acid, CH6NO3P, abbreviated as (Aminomethylphosphonic acid, AMPA), is a weak organic acid with a phosphonic acid group that can bind to different metal ions primarily through the oxygen atom of the phosphonic acid group.

[0018] In a preferred embodiment, the ion exchange resin can be described as a polymer matrix composed of polyacrylate or polystyrene-divinylbenzene (or a mixture of the two). IDA and / or AMPA are embedded within, throughout, and / or on this polymer matrix. IDA and / or AMPA can be introduced during the formation of the polymer resin, which can be formed into beads to yield AMPA or IDA embedded inside and on the surface of the resin beads. Alternatively, AMPA or IDA can be applied in a subsequent step after the resin matrix is ​​formed to yield only a surface coating. In a preferred embodiment, the concentration of AMPA or IDA in the resin ranges from 20% to 70% by weight, more preferably from 40% to 60% by weight. Generally, higher concentrations of AMPA or IDA utilized result in higher metal removal rates, but if the concentration is too high, the polymer matrix may become unstable.

[0019] The pore size of the polymer matrix can vary, in one embodiment having a preferred range of 1 to 2000 nanometers. This pore size is determined by ISO 9277:2010, "The Determination of the Specific Surface Area of ​​Solids by Gas Adsorption" (BET method). The IDA / AMPA resin polymer matrix may be formed into beads with a particle size distribution ranging from 100 to 2,000 micrometers. IDA and / or AMPA-embedded resins can be mixed together in ratios of 100:0 to 0:100. Consistent bead sizes can be obtained by progressively filtering uniformly sized resin beads using several meshes with different pore sizes.

[0020] In addition, anionic ion exchange resins can also be mixed with chelating ion exchange resins embedded with IDA and / or AMPA. Two such anionic ion exchange resins are Amberlite IRA98 (methanaminium N,N,N-trimethylhydroxide) and Amberjet 9000OH (quaternary ammonium). The anionic ion exchange resin is introduced to release hydroxyl anions (OH-). This step using anionic resins is optional and does not reduce metal removal. Some metals in organic amines exist in complex form and require a chelating resin with stronger complexing strength. The additional anionic resin cannot directly capture the complexed metals but can function as a decomplexing agent. In this decomplexation mechanism known in the art, OH- is released to form metal hydroxides, which may be easier to capture by the chelating resin.

[0021] When purifying organic amines, the processes disclosed herein may feature the use of at least one ion exchange column packed with resin containing iminodiacetic acid or resin beads embedded with aminomethylphosphonic acid. This column may be fluidly connected in series or parallel with another ion exchange column packed with other materials (i.e., resin embedded with aminomethylphosphonic acid or resin containing iminodiacetic acid, respectively). A liquid containing the organic amine is passed through these columns, in one embodiment, at a flow rate of 1 to 30 bed volumes (BV) per hour. When used together in series, either of these columns may be positioned upstream of the other. In addition, another column may be loaded with an anion ion exchange resin and connected upstream or downstream of the IDA and / or AMPA ion exchange column, allowing the liquid containing the organic amine to be passed through the series of columns to produce highly pure organic amines. As used herein, "BV" means bed volume and refers to the volume of liquid that would come into contact with an equivalent volume of hydrated, wet-mixed bed of ion exchange resin. For example, if a 120 mL hydrated wet mixed bed of ion exchange resin is used, 1 BV means that 120 mL of organic amine contacts the mixed bed of ion exchange resin. "BV / hr" is calculated by dividing the flow rate (in mL / hr) by the bed volume (in mL).

[0022] In another embodiment, organic amines can be purified using a simple mixture of an ion exchange resin and an organic amine liquid. Once mixed, the resin reacts with the organic amine, allowing the metals to be removed from the resin. The liquid is then filtered to separate the purified organic amine from other components in the liquid.

[0023] Generally, the process temperature during the step of contacting the organic amine with the resin polymer matrix can be, for example, in one embodiment, 0° C. to 100° C., in another embodiment, 10° C. to 60° C., and in yet another embodiment, 20° C. to 40° C. If the temperature exceeds 100° C., the resin will be damaged, and if the temperature is lower than the freezing point of the organic amine, the organic amine to be treated will not be able to flow.

[0024] FIG. 1 illustrates a process for purifying an organic amine according to one embodiment of the present invention. In the embodiment illustrated in FIG. 1, the process includes a sub-boiling step followed by an ion-exchange step (contacting with a resin polymer matrix). As noted above, in other embodiments, the ion-exchange step (contacting with a resin polymer matrix) may be performed first, followed by the sub-boiling step. Turning to the operation of the embodiment illustrated in FIG. 1, the organic amine is charged into the sub-boiling vessel 5 at the material inlet 10. The sub-boiling vessel 5 is then filled with an inert gas, such as nitrogen and / or argon. In some embodiments, the purity of the inert gas is at least 99.999%. The inert gas is passed through a gas filter 15 to remove particles and dust and keep the inert gas clean. The moisture and oxygen contents within the vessel are each controlled to be less than 20 ppm. The organic amine in the sub-boiling vessel 5 is heated to the sub-boiling temperature of the organic amine, which is at least 15° C. below the normal boiling point of the organic amine. In some embodiments, if the organic amine has a normal boiling point of at least 200°C, the minimum sub-boiling temperature is 160°C lower than the normal boiling point. If the organic amine has a normal boiling point of 150°C to 200°C, the minimum sub-boiling temperature is 120°C lower than the normal boiling point. If the organic amine has a normal boiling point of less than 150°C, the minimum sub-boiling temperature is greater than 25°C. In some embodiments, the pressure in the sub-boiling vessel 5 can be under vacuum or at ambient pressure. In some embodiments, the pressure can be higher than ambient pressure, for example, due to the pressure of the gas inlet. The sub-boiling vessel is equipped with a pressure release valve to prevent pressure buildup (e.g., for safety) using a gas filter to prevent particles from entering the air when pressure (gas) is released from the sub-boiling vessel 5. Heating the organic amine in the sub-boiling vessel generates vapor, which then flows into the cooling vessel 20. In the cooling vessel 20, the vapor condenses into a liquid after natural cooling. In some embodiments, the temperature in the cooling vessel is maintained below 60°C. From the cooling vessel 20, the organic amine may be pumped through an ion exchange column 25 to further reduce the metal content.The ion exchange column is packed with a resin polymer matrix embedded with an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof, as described above. The flow rate of the organic amine through the ion exchange column is, in some embodiments, 50 bed volumes / hour or less. Upon exiting the ion exchange column 25, the purified organic amine may be stored in a storage tank 30.

[0025] In some embodiments, the entire system, including sub-boiling vessel 5, cooling vessel 20, ion exchange column 25, storage tank 30, and all connecting pipelines, is fabricated from SAE 316L grade stainless steel using electroplating, or from ultra-high purity perfluoroalkoxyalkane (PFA) or polytetrafluoroethylene (PTFE) polymers. Optionally, in some embodiments, such construction materials may be heat-resistant materials capable of withstanding temperatures exceeding 250°C, with their inner surfaces coated with ultra-high purity PFA or PTFE having a coating thickness of at least 2 mm.

[0026] In one typical embodiment, after the above process (subboiling and ion exchange), the target metal level of the organic amine is less than 20 ppb (parts per billion) when the feed solvent contains typical metal levels. The resulting organic amine contains significantly lower levels of metal and non-metal ion contaminants. Metal contaminants can include, for example, Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn. The concentration of each of these metal contaminants can be 10 ppb or less in various embodiments, and 5 ppb or less in other embodiments. Thus, organic amines obtained using the process of the present invention can be useful in applications requiring ultra-high purity products, such as pharmaceutical and electronic material manufacturing, particularly in semiconductor fabrication processes. Achieving ultra-high purity products requires high metal removal rates. In some embodiments, the process of the present invention advantageously achieves a metal removal efficiency of greater than 80% for the total of the above-listed metals from the organic amine ether fed to the process. In some embodiments, the process of the present invention advantageously provides a metal removal efficiency of greater than 90% for the combined total of the above-listed metals from the organic amine fed to the process. In some embodiments, the process of the present invention advantageously provides a metal removal efficiency of greater than 95% for the combined total of the above-listed metals from the organic amine fed to the process.

[0027] It is also desirable that the purity change of the organic amine after undergoing a process according to some embodiments of the present invention be as low as possible, as measured by conventional methods such as GC-FID. For example, in some embodiments, the purity change of the organic amine is zero percent (%) or at a level below the detection limit of the detection instrument (e.g., close to zero, e.g., 0.0001%, depending on the selection of the GC detector, column, and other measurement conditions). In other embodiments, the purity change of the organic amine after ion exchange treatment is, for example, less than 0.05% in one embodiment, and less than 0.01% in another embodiment. [Example]

[0028] Some embodiments of the present invention will now be described in detail in the following examples. However, the following examples are presented to further illustrate the invention and should not be construed as limiting the scope of the claims. Unless otherwise indicated, all parts and percentages are by weight.

[0029] Various terms and designations used in the Inventive Examples ("IE") and Comparative Examples ("CE") are explained as follows: "DVB" stands for divinylbenzene. "BV / hr" stands for bed volume / hr.

[0030] The various raw materials or components used in the examples are described as follows: N-methylethanolamine (NMEA), commercially available from The Dow Chemical Company. N-methyldiethanolamine (MDEA), commercially available from The Dow Chemical Company.

[0031] PUROMET MTS9300H is an iminodiacetic acid chelating resin commercially available from Purolite. PUROMET MTS9500H is an aminomethylphosphonic acid chelating resin commercially available from Purolite. Further details about these ion exchange resins are provided in Table 1.

[0032] [Table 1]

[0033] In the present embodiment, the sub-boiling step is performed first, and the entire system, including the sub-boiling vessel, cooling vessel, ion exchange column, bottle, and connecting pipeline, are all made of perfluoroalkoxyalkane (PFA) material.

[0034] The sub-boiling vessel has a volume of 4 liters. A heating bowl is placed under the sub-boiling vessel to heat the material inside the vessel. The sub-boiling vessel, along with the heating bowl, is placed inside a glove box filled with ultra-high purity argon (assay 99.999%) to control oxygen and moisture to <5 ppm. Particle control is at Class 100 cleanroom level. The pressure is approximately 1.5 bar.

[0035] Examples 1 to 3 (IE1 to IE3) of the present invention and Comparative Examples 1 to 3 (CE1 to CE3) NMEA is evaluated in Examples 1 to 3 of the present invention and Comparative Examples 1 to 3. NMEA has a normal boiling point of 156°C and a purity of over 99.0%. Comparative Example 1 is NMEA that has not been subjected to subboiling or ion exchange.

[0036] In the present invention, 3 liters of NMEA is added to a sub-boiling vessel. The NMEA is heated to a sub-boiling temperature of 70-90°C. As a result of heating, vapor forms in the sub-boiling vessel and flows out of the top of the sub-boiling vessel into a 4-liter cooling vessel maintained at a temperature of 20°C or less. In the cooling vessel, the vapor condenses into a liquid. For the present invention, examples 1-3 are collected from the cooling vessel and tested for purity, metal content, and water content. Water content is measured using Karl Fischer titration in accordance with ASTM E203. Metal concentrations in the solvent samples are analyzed by conventional equipment, such as an ICP-MS (inductively coupled plasma mass spectrometry) instrument available from Agilent Technology, and the analytical results are listed in the table below. The original metal levels (concentrations) and metal element ratios vary depending on the lot of the supplied solvent. Purity is measured by GC (gas chromatography). Purity is calculated by dividing the peak area of ​​the major component (100% minus the sum of all impurities, including water) by the sum of all peak areas.

[0037] Inventive Example 3 is passed through an ion exchange column as follows. The ion exchange column has a volume of 100 milliliters. 10 milliliters of the ion exchange resins shown in Table 1 are packed into the ion exchange column, using 50% of each resin. The flow rate of the subboiled organic amine is 6 bed volumes / hour for Inventive Example 3. Comparative Example 2 is NMEA, but from a different lot than Comparative Example 1. Comparative Example 3 is Comparative Example 2 passed through the ion exchange column in the same manner as Example 3, but without the subboiling step. After passing through the ion exchange column, the organic amine is collected in a sample bottle, and its purity, water content, and metal content are measured as described above.

[0038] The measured values ​​of purity, water content, and metal content are shown in Table 2.

[0039] [Table 2]

[0040] As shown in Table 2, the examples of the present invention contain much less metal than the comparative example without the subboiling step. The removal rates of most metals in the examples of the present invention are over 80%. However, the removal rates of Ca and Ni in Examples 1 and 2 of the present invention are lower than the removal rates of other metals. However, when the ion exchange step was added in Example 3 of the present invention, the removal rates of Ca and Ni increased significantly.

[0041] Example 4 (IE4) and Comparative Example 4 (CE4) DMEA is evaluated in Inventive Example 4 and Comparative Example 4. DMEA has a normal boiling point of 243°C and a purity of greater than 99.0%. Comparative Example 1 is DMEA that has not been subjected to subboiling or ion exchange.

[0042] For Inventive Example 4, 3 liters of DMEA is added to a sub-boiling vessel. The DMEA is heated to a sub-boiling temperature of 90°C. As a result of heating, vapor forms in the sub-boiling vessel and flows out the top of the sub-boiling vessel into a 4 liter cooling vessel maintained at a temperature of 20°C or less. In the cooling vessel, the vapor condenses to a liquid. For Inventive Example 4, a sample is withdrawn from the cooling vessel and tested for metals content using the techniques described above.

[0043] The measured metal content is shown in Table 3.

[0044] [Table 3] As shown in Table 3, the sub-boiling process removed over 96% of the metal content from the DMEA.

Claims

1. 1. A manufacturing process for purifying an organic amine, comprising: (a) providing the organic amine having a normal boiling point at 1 bar in a first vessel; (b) filling the first container with an inert gas; (c) heating the organic amine in the first vessel to a sub-boiling temperature, the sub-boiling temperature being at least 15° C. below the normal boiling point; (d) cooling the vapor from the first vessel in a second vessel to provide a liquid; (e) contacting the organic amine with a resin polymer matrix having embedded therein an amino compound selected from (i) iminodiacetic acid, or (ii) iminodiacetic acid and aminomethylphosphonic acid; manufacturing process, including

2. 10. The manufacturing process of claim 1, wherein steps (c) and (d) occur before step (e), and the organic amine in step (e) is the liquid from step (d).

3. 10. The manufacturing process of claim 1, wherein step (e) occurs before steps (a) through (d), and wherein the organic amine is provided to the first vessel in step (a) after contacting the resin polymer matrix.

4. 4. The process of claim 1, wherein the minimum sub-boiling temperature is 160°C lower than the normal boiling point of the organic amine when the normal boiling point is at least 200°C, 120°C lower than the normal boiling point of the organic amine when the normal boiling point is between 150°C and 200°C, and greater than 25°C when the normal boiling point of the organic amine is less than 150°C.

5. 5. The manufacturing process of claim 1, wherein after the manufacturing process step is completed, the organic amine contains Na, K, Ca, Al, Fe, Ni, Zn, Cu, Cr, and Sn at a concentration of 10 ppb or less each.

6. A manufacturing process described in any one of claims 1 to 5, wherein the water content and oxygen content in the first container after filling with the inert gas in step (b) are each less than 20 ppm.

7. The manufacturing process of any one of claims 1 to 6, wherein the resin polymer matrix comprises polyacrylate or polystyrene-divinylbenzene.

8. 8. The manufacturing process of any one of claims 1 to 7, wherein the pore size of the resin polymer matrix is ​​in the range of 1 to 2,000 nm as determined by the specific surface area of ​​the solid by gas adsorption.

9. 9. The manufacturing process according to any one of claims 1 to 8, wherein the resin polymer matrix is ​​introduced into the liquid containing the organic amine as resin beads, the particle size of the beads being in the range of 100 to 2000 μm.

10. 10. The process of any one of claims 1 to 9, wherein the organic amine comprises highly concentrated monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, dimethylethanolamine, N-methyldiethanolamine, or aminoethyleneethanolamine.

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