Method for purifying organic amine

Abstract

The present disclosure provides a method for purifying an organic amine, the method comprising: introducing a resin polymer matrix into a liquid containing at least an organic amine bonded to at least one metal element, 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, and wherein the embedded resin polymer matrix binds the at least one metal element, and removing the at least one metal element from the organic amine.

Description

Background Art

[0001] Organic amines are good ligands for metal ions, so metal impurities are a common problem in the production of organic amines. Currently, there is no reliable method for removing metal impurities from organic amines. Methods that do exist for removing metal impurities from aqueous and / or inorganic liquids leave a significant amount of metal ions in the treated liquid. An example in this regard is the use of chelating resins in treating aqueous and / or inorganic salt water. Chelating resins are typically used to selectively remove transition metals or noble metals from these liquids, while typically leaving a significant amount of metal (e.g., amounts detectable in parts per million (ppm)) in the treated liquid. Additionally, these processes are only applicable to treating wastewater, inorganic salt water, etc., and there is currently no such process for treating organic amines.

[0002] For all these reasons and more, there is a need for a method to purify organic amines. Summary of the Invention

[0003] Embodiments relate to a method for purifying an organic amine, the method comprising: introducing a resin polymer matrix into a liquid containing at least an organic amine bonded to at least one metal element, 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, and wherein the embedded resin polymer matrix binds the at least one metal element, and removing the at least one metal element from the organic amine. Detailed Description

[0004] The present disclosure relates to an organic amine purification process or method. The method requires the use of an ion exchange resin characterized by iminodiacetic acid or aminomethylphosphonic acid (or both). Iminodiacetic acid HN(CH2CO2H)2 is commonly abbreviated as IDA and is a dicarboxylic acid amine. The iminodiacetate anion can act as a tridentate ligand to form complexes with metal ions. Aminomethylphosphonic acid CH6NO3P, abbreviated as (AMPA), is a weak organic acid with a phosphonic acid group that is capable of binding different metal ions mainly through the oxygen atoms of the phosphonic acid group.

[0005] In a preferred embodiment, the ion exchange resin can be described as having a polymer matrix composed of polyacrylate or polystyrene-divinylbenzene (or a mixture of both). IDA and / or AMPA are embedded within, throughout, and / or on the polymer matrix. IDA and / or AMPA can be introduced during the formation of the polymer resin, and the resin can be formed into beads such that AMPA or IDA is embedded within and on the surface of the resin beads. AMPA or IDA can also be applied in a subsequent step after the formation of the resin matrix, resulting in only a surface coating. In a preferred embodiment, the concentration of AMPA or IDA in the resin ranges from 20 wt% to 70 wt%, and more preferably from 40 wt% to 60 wt%. Generally, using a higher concentration of AMPA or IDA results in a higher metal removal rate, but if the concentration is too high, the polymer matrix may become unstable.

[0006] The pore size of the polymer matrix can vary, with a preferred range of 1 nm to 2000 nm in one embodiment. The pore size is determined via ISO 9277:2010, i.e., by the gas adsorption method for determining the specific surface area of solids (BET method). The IDA / AMPA resin polymer matrix can be formed into beads having a particle size distribution in the range of 100 μm to 2,000 μm. Resins embedded with IDA and / or AMPA can be mixed with each other in a ratio of 100:0 to 0:100. Consistent bead sizes can be obtained by gradually filtering resin beads of uniform size through several meshes with different pore sizes.

[0007] Alternatively, anion exchange resins can also be mixed with chelating ion exchange resins embedded with IDA and / or AMPA. Two such anion exchange resins are Amberlite IRA98 (methylamine N,N,N-trimethyl hydroxide) and Amberjet9000OH (quaternary ammonium). The anion exchange resin is introduced to release hydroxyl anions (OH-). This step, i.e., the anion resin, is optional and does not reduce metal removal. Some metals in organic amines exist in the form of complexes and require chelating resins with stronger complexation strength. Additional anion resins do not and cannot directly capture complexed metals, but they can act as decomplexing agents. This mechanism of decomplexation, known in the art, releases OH- to form metal hydroxides, which can be more easily captured by the chelating resin.

[0008] When purifying organic amines, the process disclosed by the present invention may be characterized by using at least one ion exchange column filled with a resin containing iminodiacetic acid or resin beads embedded with aminomethylphosphonic acid. The column may be fluidly connected in series or in parallel to another ion exchange column filled with another material (i.e., resin beads embedded with aminomethylphosphonic acid or resin containing iminodiacetic acid, respectively). In one embodiment, the liquid containing the organic amine is passed through these columns at a flow rate of 1 to 30 bed volumes (BV) per hour. When used in series, either of these columns may be placed upstream of the other. Additionally, other columns may be loaded with anion exchange resins and connected upstream or downstream of the IDA and / or AMPA ion exchange columns, such that the liquid containing the organic amine is passed through this series of columns to produce a highly pure organic amine.

[0009] In another embodiment, simple mixing of the ion exchange resin with the amine liquid may also be used to purify the organic amine. Once mixed, the resin reacts with the organic amine and removes metals from them. The liquid is then filtered to separate the purified organic amine from other components in the liquid.

[0010] Most types of metals can be effectively removed using these ion exchange resins. Notably, the disclosed process removes Ca, Sr, Ba, Fe, Mn, Cu, and Zn, which are particularly difficult to remove, from the organic amine. The types of metals may also include Li, Na, K, Mg, Al, Cr, Co, Ni, Ag, Cd, Pb, Sb, Sn, Ru, Rh, and other types of metals used in electronic devices. The types of captured metal ions may also include Cs, Ga, Hg, Se, Te, Tl, V, U, Ti, Au, Hf, Ir, Pt, W, and any other metal ions that can form bonds with IDA and / or AMPA. The total metal removal rate is approximately 90%, with the iron removal rate exceeding 80%. The content of these metals can be reduced to less than 1 ppm to parts per billion (ppb) (e.g., 100 ppb), and even to the scarce level of parts per trillion (ppt). This is a great improvement over current purification technologies.

[0011] Organic amines that can be purified by using this method include, but are not limited to, highly concentrated (having less than 1 wt% water, preferably less than 0.1%) N-methylethanolamine or similar chemical structures such as monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, aminoethyl ethanolamine, etc. These nearly pure amines can also be mixed together. In a preferred embodiment, the optimal temperature for purifying the organic amine ranges from the freezing point of the liquid organic amine to a maximum of 70 °C. In the same preferred embodiment (or another), the viscosity of the organic amine to be purified is in the range of 10 cP to 100 cP (as measured by ASTM D7042), and the pH value of the 0.1 mol / L aqueous solution is in the range of 10 to 13 (as measured by ASTM E70).

[0012] Example

[0013] Example 1

[0014] In this example, the organic amine N-methylethanolamine was purified under controlled tests by using a resin embedded with iminodiacetic acid (MTS9300 from Purolite). MTS9300 is for wastewater treatment. It is not currently considered a potential treatment method for organic amines, and there are significant differences between wastewater treatment and organic amine treatment, including the number of metal types, metal concentrations, metal forms, pH values, liquid viscosities, compatibilities, etc.

[0015] As part of this purification method, the MTS9300 resin was converted to the hydrogen form. Another iminodiacetic acid resin (DS-22 from and a resin embedded with aminomethylphosphonic acid (MTS9500 and DS-21 ) were also tested, and they were all converted to the hydrogen form. Other resins were used as part of this test for comparison, including MTS9570 IRC76 and IRA98 as well as UP252 and 9000OH

[0016] Table 1. Iminodiacetic Acid and Aminomethylphosphonic Acid Resins Information on the resins used can also be seen in Tables 1 and 2 below.

[0016] Table 1. Iminodiacetic Acid and Aminomethylphosphonic Acid Resins

[0017]

[0018] Table 2. Other Ion Exchange Resins for Comparison

[0019]

[0020] Each resin was tested by taking a certain volume of each resin (100 mL in dehydrated form) and then rinsing them with 1 L of deionized water. The washed resins were then dried in vacuo at 50 °C and 10 mmHg for 24 hours. Each dried resin was then loaded into a Teflon column with an inner diameter of 50 mm and a length of 150 mm. Then, the organic amine (N-methylethanolamine) was passed through the column packed with the resin at a rate of 2 BV / hr to 10 BV / hr to effect resin water displacement. The flow rate conditions were adjusted as needed to purify an appropriate amount of the organic amine (the values shown in Table 3A). The organic amine (N-methylethanolamine) was passed through the packed column for 15 minutes, and then a sample of the purified amine was placed into a 50 mL PFA bottle. The comparative resin was tested in the same manner with the relevant formulations and flow rates shown in Table 3B.

[0021] Table 3A. Resin Formulations and Flow Rate Conditions

[0022]

[0023] Table 3B. Comparative Resin Formulations and Flow Rate Conditions

[0024]

[0025] The metal concentration in the purified N-methylethanolamine sample was then analyzed by inductively coupled plasma mass spectrometry (ICP-MS). The standard methods for these ICP-MS tests were used and performed in triplicate. The results of the ICP-MS tests can be seen in Tables 4 - 8 below. It should be noted that the metal concentration and metal element ratio before purification varied depending on the batch of N-methylethanolamine used in each test. The same differences between batches will be found in any other type of organic amine tested, and the batch information can be seen in Tables 3A and 3B.

[0026] Table 4. Evaluation Results

[0027]

[0028] Table 5. Evaluation Results (Example 5)

[0029] Item Original Value Example 5 Li 0.01 0 Na 9.7 0.67 Mg 0.59 0.16 Al 0.26 0.33 K 31.5 1.46 Ca 56 4.57 Cr 0.19 0.12 Mn 0.46 0.24 Fe 15.4 3.05 Co 0.01 0.01 Ni 0.36 0.28 Cu 7.16 0.81 Zn 14.1 3.55 Sr 0.03 0.02 Ru 0.01 0.01 Rh 0.01 0.02 Pd 0.05 0.14 Ag 0.02 0.12 Cd 0.05 0.03 Sn 0.14 0.38 Sb 0.08 0.05 Ba 0.02 0.02 Pb 0.08 0.05 Total Metals 136 16.1 Removal Rate 88.2％ Iron Removal Rate 80.2％

[0030] Table 6. Evaluation Results (Comparative Examples 1 and 2)

[0031] Item Original Value Comparative Example 1 Comparative Example 2 Li 0.38 0.03 0 Na 119 18.3 2.89 Mg 4.9 1.00 0.10 Al 5.1 1.00 0.60 K 10 0 0.68 Ca 92 4.00 1.25 Cr 0.51 0.86 1.71 Mn 6.92 5.40 6.30 Fe 137 119 95 Co <0.1 0 0 Ni 0.51 0 0.00 Cu 5.6 6.00 4.22 Sr 0.12 0.05 0.05 Ru 0 0 0 Rh 0.02 0 0 Pd 0.07 0 0 Ag 0.11 0.00 0 Cd 0.19 0.06 0 Sn 0.50 0 0 Sb 0.11 0.08 6.28 Ba <0.1 1.01 0 Pb 0.72 0.10 0 Total Metals 384 157 119 Removal Rate 59.1％ 68.9％ Iron Removal Rate 13.1％ 30.7％

[0032] Table 7. Evaluation Results (Comparative Example 3)

[0033] Item Original Value Comparative Example 3 Li 0 0 Na 1.41 0.80 Mg 0.73 0.18 Al 0.60 0.47 K 37 1.06 Ca 7.20 14.7 Cr 0 1.14 Mn 0 0 Fe 1.29 3.18 Co 0 0 Ni 0.16 0 Cu 42 16.0 Zn 5.50 0.70 Sr 0 0.70 Ru 0 0 Rh 0 0 Pd 0 0 Ag 0 0 Cd 0 0 Sb 0 9.0 Ba 0 0 Pb 0 0 Total Metals 96 48 Removal Rate 50.0％ Iron Removal Rate Increase

[0034] Table 8. Evaluation Results (Comparative Example 4)

[0035] Item Original Value Comparative Example 4 Li 0.72 0 Na 356 40 Mg 220 24 Al 686 22 K 146 41 Ca 1789 483 Cr 5.2 1.30 Mn 257 25 Fe 136 84 Co 0.44 0.12 Ni 4.9 0.90 Cu 18 5.80 Sr 3.0 0.90 Ag 0.1 0 Cd 0 0 Sn 22 7.00 Ba 3.2 0.19 Pb 89 1.90 Total Metals 4170 936 Removal Rate 77.5％ Iron Removal Rate 38.2％

[0036] As shown above, iminodiacetic acid resin ( MTS9300) and aminomethylphosphonic acid resin ( MTS9500) or their mixtures can effectively remove various metals from N-methylethanolamine. For most of the tested embodiments, the total metal removal rate is far higher than 90%. Iron (a particularly difficult ion to remove) can be reduced by more than 80% by the method disclosed in the present invention. Tested comparative chelating resins such as MTS9570 can remove at most 77.5% of the total metal ions present in the organic amine and 38.2% of the iron. Therefore, the use of iminodiacetic acid resin and aminomethylphosphonic acid resin is a novel and effective method for purifying organic amines.

Claims

1. A method for purifying an organic amine, the method comprising: introducing a resin polymer matrix into a liquid containing at least an organic amine bonded to at least one metal element, wherein the resin polymer matrix is embedded with an amino compound, which is a combination of iminodiacetic acid and aminomethylphosphonic acid, and wherein the embedded resin polymer matrix binds the at least one metal element, and removing the at least one metal element from the organic amine, wherein the organic amine is selected from N-methylethanolamine, monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, and aminoethyl ethanolamine having less than 1% by weight of water.

2. The method according to claim 1, wherein the resin polymer matrix comprises polyacrylate or polystyrene-divinylbenzene.

3. The method according to claim 1, wherein the pore size of the resin polymer matrix is in the range of 1 nm to 2,000 nm, as determined by the specific surface area of the solid obtained by gas adsorption.

4. The method according to claim 1, wherein the resin polymer matrix is introduced into the liquid containing the organic amine as resin beads, and the particle size of the beads is in the range of 100 μm to 2,000 μm.

5. The method according to claim 1, wherein an anion exchange resin is further introduced into the liquid.

6. The method according to claim 1, wherein the temperature of the liquid is in the range from the freezing point to 70 °C.

7. The method according to claim 1, wherein the flow rate of the liquid is in the range of 1 to 30 bed volumes per hour (BV / hr).

8. The method according to claim 1, wherein more than 80% of the metal element is removed from the liquid containing at least an organic amine bonded to at least one metal element.

9. The method according to claim 1, wherein after introducing the resin polymer matrix into the liquid containing at least an organic amine bonded to at least one metal element, the concentration of the metal element in the liquid containing at least the organic amine is less than 1 ppm.

10. The method according to claim 1, wherein the organic amine is selected from monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, and aminoethyl ethanolamine having less than 1% by weight of water.

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