Organic amine purification method

Abstract

1. A method for the purification of organic amines, comprising introducing a resin polymer matrix into a liquid containing at least one organic amine bound to at least one metal element, wherein the resin polymer matrix has embedded therein an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof, wherein the embedded resin polymer matrix binds to the at least one metal element, and the at least one metal element is removed from the organic amine.

Description

[Technical field]

[0001] Introduction Organic amines are good ligands for metal ions, and therefore metal impurities are a common problem when producing organic amines. Currently, there are no reliable methods for removing metal impurities from organic amines. Existing methods for removing metal impurities from aqueous and / or inorganic liquids leave significant metal ions in the treated liquid. One example of this is the use of chelating resins in treating aqueous and / or inorganic brines. Chelating resins are typically used to selectively remove transition or precious metals from these liquids, and while common, leave significant amounts of metals (e.g., detectable parts per million) in the treated liquid. In addition, these processes are only suitable for treating wastewater, inorganic brines, and the like, and no such processes are currently available for treating organic amines.

[0002] For all these reasons and more, a need exists for a method for the purification of organic amines. Summary of the Invention

[0003] An embodiment relates to a method for the purification of an organic amine comprising introducing a resin polymer matrix into a liquid containing at least one organic amine bound to at least one metal element, the resin polymer matrix having embedded therein an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or combinations thereof, the embedded resin polymer matrix binding to the at least one metal element and the at least one metal element being removed from the organic amine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0004] The present disclosure relates to an organic amine purification process or method, which involves the use of ion exchange resins featuring iminodiacetic acid or aminomethylphosphonic acid (or both). Iminodiacetic acid, HN(CH CO H), often abbreviated as IDA, is a dicarboxylic amine. The iminodiacetate anion can function as a tridentate ligand to 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.

[0005] In a preferred embodiment, the ion exchange resin may be described as a polymer matrix consisting 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 may be introduced during the formation of the polymer resin, which may be formed into beads resulting in AMPA or IDA embedded inside and on the surface of the resin beads. Alternatively, AMPA or IDA may be applied in a subsequent step after the resin matrix is ​​formed resulting in 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 40% to 60% by weight. In general, a higher concentration of AMPA or IDA utilized will result in a higher metal removal rate, however, if the concentration is too high, the polymer matrix may become unstable.

[0006] The pore size of the polymer matrix can vary, and in one embodiment has a preferred range of 1-2000 nm. This pore size is determined via ISO 9277:2010, Determination of the specific surface area of ​​solids by gas adsorption (BET method). The IDA / AMPA resin polymer matrix can be formed into beads with a particle size distribution ranging from 100 to 2,000 μ. IDA and / or AMPA embedded resins can be mixed together in a ratio of 100:0 to 0:100. Consistent bead size can be obtained by stepwise filtration of uniformly sized resin beads using several meshes with different pore sizes.

[0007] In addition, anion ion exchange resins can also be mixed with chelating ion exchange resins embedded with IDA and / or AMPA. Two such anion ion exchange resins are Amberlite IRA98 (methanaminium N,N,N-trimethylhydroxide) and Amberjet 9000OH (quaternary ammonium). Anion ion exchange resins are introduced to release hydroxyl anions (OH-). This step is optional and does not reduce metal removal, anion resin. Some metals in organic amines are present in complex form and require chelating resins with stronger complexing strength. The additional anion resin does not and cannot directly capture the complexed metals, but can function as a decomplexing agent. The mechanism for this decomplexation known in the art is to release OH- to form metal hydroxides that may be easier to capture by chelating resins.

[0008] When purifying organic amines, the disclosed process 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). The liquid containing the organic amine is passed through these columns at a flow rate of 1-30 bed volumes (BV) per hour in one embodiment. When used together in series, either of these columns may be placed upstream of the other. In addition, other columns may be loaded with anion ion exchange resins and connected upstream or downstream of the IDA and / or AMPA ion exchange columns to pass the liquid containing the organic amine through the series of columns to produce extremely pure organic amines.

[0009] In another embodiment, a simple mixture of an ion exchange resin and an amine liquid can also be utilized to purify the organic amine. When mixed, the resin reacts with the organic amine, allowing the metals to be removed from the resin. The liquid is then filtered, and the purified organic amine is then separated from the other components in the liquid.

[0010] The use of these ion exchange resins can effectively remove most types of metals. Notably, the disclosed process removes Ca, Sr, Ba, Fe, Mn, Cu, and Zn from organic amines, which are particularly difficult to remove. The types of metals can include Li, Na, K, Mg, Al, Cr, Co, Ni, Ag, Cd, Pb, Sb, Sn, Ru, Rh, and other types of metals utilized by electronic devices. The types of metal ions captured can also include Cs, Ga, Hg, Se, Te, Tl, V, U, Ti, Au, Hf, Ir, Pt, W, and any other metal ion that can form bonds with IDA and / or AMPA. The total metal removal is about 90%, and the iron removal is greater than 80%. The content of these metals can be reduced to less than parts per million to parts per billion (e.g., 100 parts per billion) and even parts per trillion levels of rarity. This is a dramatic improvement over current purification technology.

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

[0012] Example 1 In this example, an organic amine, N-methylethanolamine, was purified under controlled testing through the use of an iminodiacetic acid embedded resin (Puromet® MTS9300 supplied by Purolite). Puromet® MTS9300 is a wastewater treatment. Currently, it is not recognized as a potential treatment for organic amines, and there are large differences between wastewater treatment and organic amine treatment, including number of metal species, metal concentration, metal form, pH value, liquid viscosity, compatibility, etc.

[0013] As part of this purification method, Puromet® MTS 9300 resin was converted to hydrogen form. Another iminodiacetic acid resin (DS-22 supplied by Organo®) was also tested, as was an aminomethylphosphonic acid embedded resin (Puromet® MTS 9500 (Purolite® and DS-21 (Organo®)), all of which were also converted to hydrogen form. For comparison, other resins were utilized as part of this study, including Puromet® MTS 9570 (Purolite®), Amberlite® IRC 76, and Amberlite® IRA 98 (Organo®), as well as Amberlite® UP 252 and Amberjet® 9000 OH (DuPont®). Information regarding the resins utilized can also be found in Tables 1 and 2 below.

[0014] [Table 1]

[0015] [Table 2]

[0016] Each resin was tested by taking a volume of each (100 mL in dehydrated form) and then washing them with 1 L of deionized water. The washed resins were then dried at 50 °C and 10 mmHg vacuum for 24 hours. Each dried resin was then packed into a Teflon column with an internal diameter of 50 mm and a length of 150 mm. The resin-packed column was then run with an organic amine (N-methylethanolamine) at a rate of 2-10 BV / hr to allow for resin-water exchange. Flow conditions were adjusted as necessary to purify the appropriate amount of organic amine (values ​​shown in Table 3A). The organic amine (N-methylethanolamine) was run through the packed column for 15 minutes, after which a sample of the purified amine was collected in a 50 mL PFA bottle. This same test was performed on a comparison resin with the relevant recipe and flow rates shown in Table 3B.

[0017] [Table 3]

[0018] [Table 4]

[0019] The concentrations of metals in the purified N-methylethanolamine samples were then analyzed by Inductively Coupled Plasma-mass spectrometry (ICP-MS). Standard methodology was utilized for these ICP-MS tests and were performed in triplicate. The results of the ICP-MS tests can be found in Tables 4-8 below. It should be noted that the metal concentrations and metal element ratios prior to purification varied with the lot of N-methylethanolamine utilized in each test. This same lot-to-lot variation was found with any of the other types of organic amines tested and the lot information can be found in Tables 3A and 3B.

[0020] [Table 5]

[0021] [Table 6]

[0022] [Table 7]

[0023] [Table 8]

[0024] [Table 9]

[0025] As shown, both iminodiacetic acid resin (Puromet® MTS9300) and aminomethylphosphonic acid resin (Puromet® MTS9500), or a mixture thereof, can efficiently remove various metals from N-methylethanolamine. In most of the tested embodiments, the total metal removal is well above 90%. Iron, an ion that is significantly more difficult to remove, can be reduced by more than 80% by the disclosed method. Comparative chelating resins tested, such as Puromet® MTS9570, only removed at best 77.5% of the total metal ions and 38.2% of iron present in the organic amine. Thus, the use of iminodiacetic acid resin and aminomethylphosphonic acid resin is a novel and effective means of purifying organic amines. The present invention includes the following aspects. Section 1. 1. A process for the purification of an organic amine, comprising: introducing a resin polymer matrix into a liquid containing at least one organic amine bonded to at least one metal element; the resin polymer matrix has embedded therein an amino compound selected from the group consisting of iminodiacetic acid, aminomethylphosphonic acid, or a combination thereof; the embedded resin polymer matrix bonds to the at least one metallic element; The method of claim 1, wherein the at least one metal element is removed from the organic amine. Section 2. Item 10. The method of item 1, wherein the resin polymer matrix comprises polyacrylate or polystyrene-divinylbenzene. Section 3. Item 3. The method according to item 1, 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. Section 4. Item 2. The method according to item 1, 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 size range of 100 to 2000 μm. Section 5. Item 11. The method of item 1, wherein an anion ion exchange resin is also introduced into the liquid. Section 6. Item 1. The method according to item 1, wherein the temperature of the liquid is in the range of freezing to 70°C. Section 7. Item 3. The method according to item 1, wherein the flow rate of the liquid is in the range of 1 to 30 BV / hour. Section 8. Item 11. The method of item 1, wherein greater than 80% of the metal element is removed from the liquid containing at least one organic amine bound to at least one metal element. Section 9. Item 1. The method of item 1, wherein after introducing the resin polymer matrix into a liquid containing at least one organic amine bound to at least one metal element, the concentration of the metal element in the liquid containing at least one organic amine is less than 1 part per million. Section 10. 2. The method of claim 1, wherein the organic amine comprises highly concentrated monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, or aminoethyleneethanolamine.

Claims

1. A method for the purification of organic amines containing less than 1% by weight of water, comprising: introducing a resin polymer matrix into a liquid containing at least one organic amine bonded to at least one metal element; The resin polymer matrix has embedded therein an amino compound that is a combination of iminodiacetic acid and aminomethylphosphonic acid; the embedded resin polymer matrix bonds to the at least one metallic element; The method of claim 1, wherein the at least one metal element is removed from the organic amine.

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

3. 2. The method of claim 1, 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.

4. 2. The method of claim 1, wherein the resin polymer matrix is ​​introduced into the liquid containing the organic amine as resin beads, the particle size of the beads ranging from 100 to 2000 μm in size.

5. 2. The method of claim 1, wherein the organic amine comprises monoethanolamine, diethanolamine, triethanolamine, isopropanolamine, diisopropanolamine, triisopropanolamine, N-methyldiethanolamine, or aminoethyleneethanolamine, and the organic amines contain less than 1% by weight of water.

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