Method for purifying aqueous organic amine solutions and use thereof

Abstract

The application discloses a purification method of an organic amine aqueous solution, which comprises the following steps: S01: converting an initial acrylic ion exchange resin into a hydrogen type; converting the obtained hydrogen type acrylic ion exchange resin into an ammonium type; S02: adopting the obtained ammonium type acrylic ion exchange resin to perform primary purification on the organic amine aqueous solution to be purified, so as to obtain a first liquid; and S03: adopting a chelating type filter membrane to perform secondary purification on the first liquid, so as to remove almost all or part of metal ions in the organic amine aqueous solution to be purified, and to obtain a second liquid. Another purification method of the organic amine aqueous solution and the application of the two purification methods are also provided. The method can be used for the purification treatment of a large amount of the organic amine aqueous solution, can remove sodium and potassium ions in the organic amine aqueous solution to below 1 ppb, and the device used for the purification has simple structure and low cost.

Description

Technical Field

[0001] This invention belongs to the field of electronic chemical purification technology, specifically relating to a method for purifying aqueous solutions of organic amines and the application of this purification method. Background Technology

[0002] Electronic chemicals are among the key materials used in the manufacturing of integrated circuits (ICs), applied to processes such as chip cleaning, etching, doping, and deposition. In the IC field, 8-inch and smaller wafers require electronic chemicals to meet or exceed G3 grade, with metal ion impurities below 1 ppb. With the rapid development of IC technology, there is an urgent need to prepare electronic-grade raw materials with the lowest possible metal ion content. Organic amines themselves do not contain metal elements and are widely used in developers and cleaning agents in the IC field. However, currently, domestically produced organic amine compounds are mainly industrial grade, containing a relatively high amount of metal ion impurities. The presence of metal ions such as sodium, iron, and copper can reduce the minority carrier lifetime of silicon wafers; therefore, it is necessary to remove as many metal ions as possible from organic amines before they can be used in the electronics industry.

[0003] Alkali metal ions are ubiquitous in the environment and are often the main metal ion impurities in feed solutions. In general production processes, organic amines easily produce sodium and potassium residues exceeding 100 ppb, or even ppm levels. Ion exchange resins are commonly used in the electronics industry to prepare ultrapure water, but there are few reports on their use for purifying metal ions from organic alkalis. Cation exchange resins exhibit a certain selectivity in the adsorption of metal ions, typically with the following preference order: Fe... 3+ >Al 3+ >Ca 2+ >Mg 2+ >K + Na + This is related to the hydrated ionic radius and charge density of the ions, and sodium and potassium ions are usually the most difficult to remove.

[0004] Removing metal ions from alkaline solutions using ion exchange resins is more challenging, as iron may be present in an alkaline environment as Fe(OH)6. 3- The presence of anions leads to low removal efficiency of iron from organic amines by cation exchange resins. Furthermore, the acidic groups in cation exchange resins often neutralize with alkaline solutions, resulting in a decrease in the concentration of amines in the effluent. JP03-167160A proposes increasing the crosslinking degree of polystyrene-based sulfonic acid resins (≥10%) to reduce the resin's exchange capacity for quaternary ammonium cations, allowing metal ions to be preferentially exchanged and removed by the resin, thereby weakening the acid-base neutralization effect between strong acid resins and alkaline solutions. While highly crosslinked strong acid cation exchange resins can reduce metal ion content, they suffer from drawbacks such as low exchange capacity (below 2 eq / L), high resin usage costs, and poor economic efficiency. Summary of the Invention

[0005] In view of all or part of the deficiencies of the prior art described above, the purpose of this invention is to provide a method and application for purifying organic amine aqueous solutions, which can be used for the purification of large volumes of organic amine aqueous solutions, and can remove sodium and potassium ions in organic amine aqueous solutions to below 1 ppb. The purification device is simple in structure and low in cost.

[0006] To achieve the above-mentioned objectives, the present invention provides the following technical solution:

[0007] This invention provides a method for purifying an aqueous solution of an organic amine, comprising the following steps:

[0008] S01: Convert the initial acrylic ion exchange resin to the hydrogen form; convert the obtained hydrogen form acrylic ion exchange resin to the ammonium form;

[0009] S02: The obtained ammonium-type acrylic ion exchange resin is used to purify the aqueous solution of the organic amine to be purified once to obtain the first solution;

[0010] S03: The first solution is purified a second time using a chelating filter membrane to remove almost all or part of the metal ions in the aqueous solution of the organic amine to be purified, thus obtaining the second solution.

[0011] This invention employs a two-stage purification process—combined filtration using acrylic ion exchange resin and a chelating filter membrane—to reduce sodium and potassium ions in an organic amine aqueous solution from over 100 ppb to below 1 ppb, and heavy metal ions such as iron ions from over 100 ppb to below 10 ppb. The filtration process essentially preserves the concentration of the organic amine, demonstrating excellent purification performance. The resulting electronic-grade organic amine aqueous solution meets the electronics industry's demand for organic amines with extremely low metal residues. The purification method is simple, low-cost, and suitable for purifying large volumes of organic amine aqueous solutions. By converting the hydrogen-form acrylic ion exchange resin to the ammonium-form, acid-base neutralization between the acidic groups in the ion exchange resin and the alkaline solution is avoided, preventing a decrease in the amine concentration in the first solution from affecting subsequent filtration. Furthermore, the acrylic ion exchange resin has a high exchange capacity and low operating cost.

[0012] In step S01, the process of converting to the hydrogen form is as follows: the initial acrylic ion exchange resin is soaked in an acid solution. Specifically, the initial acrylic ion exchange resin can be soaked in an acid solution with a concentration of 2-10 BV (BV is the resin bed volume) and 2-20% for 12-48 hours, and the acid solution is discharged at a rate of 1-3 BV / h. After the acid solution is completely discharged, it is rinsed with ultrapure water at a rate of 10-20 BV / h (stopped when the conductivity of the effluent is <1 μS / cm).

[0013] The acid solution may be selected from at least one of analytical grade or electronic grade hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid.

[0014] In step S01, the conversion to the ammonium form involves soaking the hydrogen-form acrylic ion exchange resin in an alkaline solution. Specifically, the hydrogen-form acrylic ion exchange resin can be soaked in an alkaline solution of 1.5-2 BV for 12-48 hours, and the alkaline solution can be discharged at a rate of 1-3 BV / h.

[0015] The alkaline solution can be an aqueous solution of the organic amine to be purified. Specifically, it can be an aqueous solution of the organic amine with a low concentration of major metal ion impurities or with metal ion impurities already removed, to avoid introducing new quaternary ammonium cations and to prevent the resin from adsorbing a large amount of metal ions before use. Of course, other types of organic amines can also be used to reduce the consumption of the aqueous solution of the organic amine to be purified.

[0016] In step S02, the first purification process is as follows: the ammonium-type acrylic ion exchange resin obtained in step S01 is soaked in the organic amine aqueous solution to be purified for 0.5-1h, and the organic amine aqueous solution after the first purification is discharged at a rate of 1-20 BV / h, more preferably 3-15 BV / h.

[0017] In step S03, during the secondary purification process, the filtration flow rate of the first liquid is 1-200 mL / min, more preferably 50-150 mL / min, and the effluent is collected and its concentration and metal ion content are detected.

[0018] The initial acrylic ion exchange resin has a skeleton of macroporous polyacrylate resin, a functional group of carboxyl group, and a particle size distribution of 300-1600 μm.

[0019] In step S03, the chelating filter membrane is a modified ultra-high molecular weight polyethylene membrane, with functional groups including iminodiacetic acid and meglumine. The chelating filter membrane is loaded into a capsule filter made of high-density polyethylene. The iminodiacetic acid and meglumine groups on the chelating filter membrane can chelate heavy metal ions. After the organic amine aqueous solution is filtered through the capsule filter, the heavy metal ions are retained in the capsule filter.

[0020] The organic amine aqueous solution to be purified is selected from one or more of the following: ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, butylamine, isobutylamine, tert-butylamine, ethylenediamine, diethylenetriamine, pentamethyldiethylenetriamine, triethylenetetramine, ethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyldiethanolamine, isopropanolamine, diisopropanolamine, 2-amino-2-methylpropanol, and hydroxyethylethylenediamine aqueous solution.

[0021] This invention also provides a method for purifying an aqueous solution of an organic amine, comprising the following steps:

[0022] S11: A chelating group is introduced onto a spherical macroporous acrylic resin white ball to obtain a primitive acrylic ion exchange resin, wherein the chelating group is iminodiacetic acid;

[0023] S12: Convert the original acrylic ion exchange resin to the hydrogen form; convert the obtained hydrogen form acrylic ion exchange resin to the ammonium form;

[0024] S13: The obtained ammonium-type acrylic ion exchange resin is used to purify the aqueous solution of the organic amine to be purified, removing almost all or part of the metal ions in the aqueous solution of the organic amine to be purified.

[0025] This invention introduces chelating groups onto acrylic ion exchange resins, thereby retaining the excellent ability and exchange capacity of acrylic ion exchange resins to remove alkali metal ions, while significantly improving the ability to remove heavy metal ions such as iron and copper ions. It reduces sodium and potassium ion concentrations in organic amine aqueous solutions from over 100 ppb to below 1 ppb, and heavy metal ion concentrations such as iron ions from over 100 ppb to below 10 ppb.

[0026] In step S11, the preparation process of the original acrylic ion exchange resin is as follows: macroporous resin white spheres are prepared using methyl acrylate and divinylbenzene as monomers, and then the macroporous resin white spheres are converted into amides by heating in tetraethylenepentamine to obtain ammonolytic spheres. The ammonolytic spheres and chloroacetic acid are heated in liquid alkali to remove hydrogen chloride.

[0027] This invention also provides the application of any of the above-mentioned methods for purifying aqueous organic amine solutions in the field of integrated circuits. Specifically, it can be used in processes such as chip cleaning, etching, doping, and precipitation. Attached Figure Description

[0028] To more clearly illustrate the technical solutions in the specific embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0029] Figure 1 This is a schematic flowchart of a method for purifying an aqueous solution of an organic amine provided by the present invention. Detailed Implementation

[0030] The technical solutions in specific embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0031] It should be noted that, in order to describe the technical solution more specifically, the steps described in the following embodiments do not strictly correspond one-to-one with the steps described in the invention content section.

[0032] Comparative Example 1

[0033] Reference Figure 1 Step 1: Take 50 mL of AmberLite IRC83 resin (macroporous acrylic weak acid cation exchange resin, with carboxyl functional group, particle size distribution of 500-750 μm, and exchange capacity ≥4.7 eq / L) and fill it into a polytetrafluoroethylene (or glass, polypropylene, polymethyl methacrylate, polyethylene) ion exchange column with an inner diameter of 40 mm and a height of 450 mm. Rinse with ultrapure water (resistivity ≥18 MΩ·cm, preferably 18.2 MΩ·cm) until the effluent is clear, odorless, and free of fine fragments of initial acrylic ion exchange resin. Collect the effluent in a polytetrafluoroethylene (or polyethylene, polypropylene) bottle.

[0034] Step 2: Add 6.5 BV of 3.5% electronic-grade sulfuric acid to the ion exchange column to soak the initial acrylic ion exchange resin for 24 hours to convert the initial acrylic ion exchange resin to the hydrogen form. Then, drain the acid solution at a flow rate of 1.5 BV / h. After draining the acid solution, rinse with ultrapure water at 15 BV / h. Collect the effluent in a beaker and test its conductivity. Stop rinsing when the conductivity of the effluent is <1 μS / cm, and drain the ion exchange column completely.

[0035] Step 3: Add 2 BV of 50% ethylenediamine aqueous solution (stock solution, metal ion content: Na: 155 ppb, K: 99 ppb, Fe: 64 ppb, Cu: 2.37 ppb) to the ion exchange column and soak for 24 hours to convert the hydrogen-form acrylic ion exchange resin to the ammonium-form acrylic ion exchange resin. Then, drain the alkali solution at a flow rate of 1.5 BV / h and detect the amine concentration in the effluent. If the pH and alkali concentration of the drained alkali solution decrease significantly, continue to rinse the ion exchange column with this ethylenediamine aqueous solution at 1.5 BV / h until the pH and alkali concentration of the effluent are similar to those of the stock solution (50% ethylenediamine aqueous solution) (without significant decrease). The resin conversion is then complete. (Insufficient organic amine aqueous solution during conversion will lead to incomplete conversion and a decrease in product concentration.) Drain the ion exchange column. The conversion to ammonium form consumes 150 ml of ethylenediamine aqueous solution, with a drain flow rate of 1.5 BV / h.

[0036] Step 4: Add a 50% ethylenediamine aqueous solution to the ion exchange column for purification. After soaking for 0.5 hours, drain the effluent at a flow rate of 5 BV / h and collect it in a PTFE bottle. After filtering 3 L of the ethylenediamine aqueous solution, continue filtering and take a sample of the effluent to test the metal ion content and alkali concentration. Depending on the product specifications, the content of the main metal ions in the organic amine aqueous solution can be reduced by using one ion exchange column for filtration once, multiple filtrations, or multiple ion exchange columns in series. In this embodiment, one ion exchange column is used for filtration once.

[0037] Comparative Example 2

[0038] The difference from Comparative Example 1 is that the resin used was Zhengguang D113 resin (macroporous acrylic weak acid cation exchange resin, with carboxyl functional groups, particle size distribution of 315-1250um, and exchange capacity ≥4.4eq / L). The ammonium-converting process consumed 170ml of ethylenediamine aqueous solution, and the discharge flow rate was 1.5BV / h.

[0039] Comparative Example 3

[0040] The difference from Comparative Example 2 is that the hydrogen form conversion was completed by immersion in 5% analytical grade hydrochloric acid (5 BV), with the acid solution discharged at a flow rate of 1.5 BV / h. The ammonium form conversion consumed 190 ml of ethylenediamine aqueous solution, discharged at a flow rate of 1.5 BV / h. During purification, the organic amine aqueous solution flow rate was 3 BV / h.

[0041] Comparative Example 4

[0042] The difference from Comparative Example 2 is that the hydrogen form conversion was completed by immersion in 5% electronic-grade hydrochloric acid (5 BV), with the acid solution discharged at a flow rate of 1 BV / h. The ammonium form conversion consumed 180 ml of ethylenediamine aqueous solution, with a discharge flow rate of 1.5 BV / h. During purification, the organic amine aqueous solution flow rate was 3 BV / h.

[0043] Comparative Example 5

[0044] The difference from Comparative Example 2 is that the hydrogen form conversion was completed by immersion in 5% electronic-grade phosphoric acid (5 BV), with the acid solution discharged at a flow rate of 2.5 BV / h. The ammonium form conversion consumed 180 ml of ethylenediamine aqueous solution, discharged at a flow rate of 1.5 BV / h. During purification, the flow rate of the organic amine aqueous solution was 10 BV / h.

[0045] Comparative Example 6

[0046] The difference from Comparative Example 2 is that the hydrogen form conversion was completed by immersion in 7 BV, 2.2% electronic-grade sulfuric acid, with the acid solution discharged at a flow rate of 3 BV / h. The ammonium form conversion consumed 170 ml of ethylenediamine aqueous solution, discharged at a flow rate of 3 BV / h. During purification, the flow rate of the organic amine aqueous solution was 15 BV / h.

[0047] Comparative Example 7

[0048] The difference from Comparative Example 2 is that the hydrogen form conversion was completed by immersion in 3 BV, 15% electronic-grade sulfuric acid, with the acid solution discharged at a flow rate of 2 BV / h. The ammonium form conversion consumed 180 ml of ethylenediamine aqueous solution, discharged at a flow rate of 2 BV / h. During purification, the flow rate of the organic amine aqueous solution was 20 BV / h.

[0049] Comparative Example 8

[0050] The difference from Comparative Example 1 is that the resin used was Purolite C100EDL resin (a gel-type styrene-based strong acid cation exchange resin with sulfonic acid groups as functional groups and an exchange capacity ≥1.9 eq / L). The ammonium-type process consumed 220 ml of ethylenediamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0051] Comparative Example 9

[0052] The difference from Comparative Example 1 is that the resin used was Purolite S930Plus resin (macroporous styrene-based chelating resin with iminodiacetic acid functional group and exchange capacity ≥50g copper / L). The ammonium-converting process consumed 200ml of ethylenediamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0053] Example 1

[0054] Based on Example 2, and referring to... Figure 1 This includes the following steps:

[0055] Step 1: Take 50 mL of Zhengguang D113 resin (macroporous acrylic weak acid cation exchange resin, with carboxyl functional group, particle size distribution of 315-1250 μm, and exchange capacity ≥4.4 eq / L) and fill it into a polytetrafluoroethylene (or glass, polypropylene, polymethyl methacrylate, polyethylene) ion exchange column with an inner diameter of 40 mm and a height of 450 mm. Rinse with ultrapure water (resistivity ≥18 MΩ·cm, preferably 18.2 MΩ·cm) until the effluent is clear, odorless, and free of fine fragments of initial acrylic ion exchange resin. Collect the effluent in a polytetrafluoroethylene (or polyethylene, polypropylene) bottle.

[0056] Step 2: Add 6.5 BV of 3.5% electronic-grade sulfuric acid to the ion exchange column to soak the initial acrylic ion exchange resin for 24 hours to convert the initial acrylic ion exchange resin to the hydrogen form. Then, drain the acid solution at a flow rate of 1.5 BV / h. After draining the acid solution, rinse with ultrapure water at 15 BV / h. Collect the effluent in a beaker and test its conductivity. Stop rinsing when the conductivity of the effluent is <1 μS / cm, and drain the ion exchange column completely.

[0057] Step 3: Add 2 BV of 50% ethylenediamine aqueous solution (stock solution, metal ion content: Na: 155 ppb, K: 99 ppb, Fe: 64 ppb, Cu: 2.37 ppb) to the ion exchange column and soak for 24 hours to convert the hydrogen-form acrylic ion exchange resin to the ammonium-form acrylic ion exchange resin. Then, drain the alkali solution at a flow rate of 1.5 BV / h and detect the amine concentration in the effluent. If the pH and alkali concentration of the drained alkali solution decrease significantly, continue to rinse the ion exchange column with this ethylenediamine aqueous solution at 1.5 BV / h until the pH and alkali concentration of the effluent are similar to those of the stock solution (50% ethylenediamine aqueous solution) (without significant decrease). The resin conversion is then complete. (Insufficient organic amine aqueous solution during conversion will lead to incomplete conversion and a decrease in product concentration.) Drain the ion exchange column. The conversion to ammonium form consumes 170 ml of ethylenediamine aqueous solution, with a drain flow rate of 1.5 BV / h.

[0058] Step 4: Add a 50% ethylenediamine aqueous solution to the ion exchange column for purification. After soaking for 0.5 hours, drain the effluent at a flow rate of 5 BV / h and collect it in a PTFE bottle. After filtering 3 L of the ethylenediamine aqueous solution, continue filtering and take a sample of the effluent to test the metal ion content and alkali concentration. Depending on the product specifications, the content of the main metal ions in the organic amine aqueous solution can be reduced by using one ion exchange column for filtration once, multiple filtrations, or multiple ion exchange columns in series. In this embodiment, one ion exchange column is used for filtration once.

[0059] Step 5: Use the effluent obtained in Step 4 as the first liquid. Filter the first liquid once using a capsule filter equipped with a chelating membrane (a commercially available 4-inch capsule filter; the functional groups of the chelating membrane include both iminodiacetic acid and meglumine, with an exchange capacity ≥20 meq and a membrane area of ​​1200 cm²). 2 The flow rate was 100 mL / min. The effluent from the capsule filter was collected as the second solution, and its concentration and metal ion content were measured. The capsule filter was washed with ultrapure water until the conductivity of the effluent was <1 μS / cm before use. Depending on the product specifications, chelating membrane filtration can be used once or multiple times to reduce the metal ion content in the organic amine. In this embodiment, only one chelating membrane filtration was used. The metal ion content of the effluent after combined filtration of 50 L of organic amine aqueous solution was Na: 0.23 ppb, K: 0.59 ppb, Fe: 2.10 ppb, Cu: 0.29 ppb.

[0060] Example 2

[0061] The difference from Example 1 is that the organic amine aqueous solution to be purified is a 75% ethanolamine aqueous solution (stock solution, metal ion content: Na: 168 ppb, K: 120 ppb, Fe: 107 ppb, Cu: 3.36 ppb). The conversion to ammonium form consumes 130 ml of ethanolamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0062] Example 3

[0063] The difference from Example 1 is that the organic amine aqueous solution to be purified is a 25% N-methyldiethanolamine aqueous solution (stock solution, metal ion content: Na: 162 ppb, K: 83 ppb, Fe: 92 ppb, Cu: 4.67 ppb). The transammonium form consumes 250 ml of the N-methyldiethanolamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0064] Example 4

[0065] The difference from Example 1 is that the organic amine aqueous solution to be purified is a 90% hydroxyethyl ethylenediamine aqueous solution (stock solution, metal ion content: Na: 210 ppb, K: 173 ppb, Fe: 46 ppb, Cu: 5.28 ppb). The ammonium-converting process consumes 120 ml of the hydroxyethyl ethylenediamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0066] Example 5

[0067] The difference from Example 1 is that the organic amine aqueous solution to be purified is a 50% diethylenetriamine aqueous solution (stock solution, metal ion content: Na: 125 ppb, K: 103 ppb, Fe: 76 ppb, Cu: 3.70 ppb). The ammonium-transfer process consumes 150 ml of the diethylenetriamine aqueous solution, with a discharge flow rate of 1.5 BV / h.

[0068] Table 1. Purification effects of Comparative Examples 1-9 and Examples 1-5

[0069]

[0070]

[0071]

[0072] Referring to the data in Table 1, the high metal ion content after purification in Comparative Example 8 indicates that the strong acid resin Purolite C100EDL, with sulfonic acid functional groups and a crosslinking degree of 7%, cannot effectively remove sodium ions from organic amines. The increased sodium ion content may be due to the resin's inability to effectively adsorb sodium ions, resulting in the release of sodium ions from the resin material into the solution during immersion. Comparative Example 9 uses Purolite S930Plus, a chelating resin with iminodiacetic acid functional groups. Besides its lower ability to remove major metal ion impurities such as sodium and potassium compared to the macroporous acrylic ion exchange resins used in Comparative Examples 1-7, its exchange capacity is also lower.

[0073] Comparative Examples 1-7 used macroporous acrylic ion exchange resins with carboxyl functional groups, which showed good performance in removing alkali metal ions. A single filtration reduced sodium and potassium ions in a 50% ethylenediamine aqueous solution to below 1 ppb, with minimal change in the concentration of the organic amine after filtration. Comparative Examples 3-7, using different acids and flow rates, filtered a 50% ethylenediamine aqueous solution, all of which reduced sodium and potassium ions to below 1 ppb. Electronic-grade acids were preferred, as they contained fewer metal ion impurities and achieved better purification results. In Comparative Example 7, the flow rate of the organic amine aqueous solution during purification was 20 BV / h. The sodium ion content after purification was close to 1 ppb. This is because as the flow rate increases, the contact time between the feed solution and the ion exchange resin shortens, reducing the average residence time in the resin bed. This shortens the time for particle diffusion and membrane diffusion of metal ions in the feed solution within the resin, ultimately leading to a decrease in mass transfer efficiency and a reduction in the resin's adsorption capacity for metal impurities in the feed solution. Reducing the flow rate is beneficial for metal ion removal, but it also means a decrease in the resin purification rate and an increase in operating costs. Taking all factors into consideration, the preferred flow rate range is 3-15 BV / h.

[0074] Example 1: After treatment with an acrylic ion exchange resin, the effluent was treated with a chelating filter membrane. Specifically, an acrylic ion exchange resin with carboxyl functional groups was first used to remove most metal ion impurities such as sodium and potassium from the organic amine aqueous solution. Then, membrane filtration was used to refine the solution, removing metal ions (such as iron and copper, which are difficult to remove) that remained in high concentrations after ion exchange resin treatment. This resulted in an organic amine aqueous solution with sodium and potassium content below 1 ppb and iron and copper content below 10 ppb, meeting the electronics industry's requirement for organic amines with extremely low metal residues. Examples 2-5: Similar treatment processes were used to treat different organic amine aqueous solutions. Combined filtration did not significantly change the concentration of the organic amine, but the sodium and potassium ion concentrations in the organic amine aqueous solution decreased from over 100 ppb to below 1 ppb, and the iron and copper ion concentrations decreased to below 10 ppb, and some even below 1 ppb, demonstrating excellent purification effects. During the filtration of organic amines of different concentrations, the macroporous acrylic ion exchange resin and the chelating filter membrane exhibited good mechanical properties. Of course, there will inevitably be some differences in the purification effect of aqueous solutions of different types of organic amines.

[0075] In Example 1, after continuously filtering 50L of a 50% ethylenediamine aqueous solution using a combined purification method with 50mL resin and a chelating filter membrane, the performance of the ion exchange resin and the chelating filter membrane remained stable. The metal ion content in the effluent showed no significant fluctuations; the contents of sodium, potassium, and copper ions were below 1 ppb, and the iron ion content was below 5 ppb. The total metal ion content was reduced by more than 90%. Detailed data on the metal ion content in the 50% ethylenediamine aqueous solution stock solution and the effluent after 50L combined filtration are shown in Table 2 below.

[0076] Table 2 shows the purification effect of the ethylenediamine aqueous solution stock solution and the combined filtration of 50L in Example 1.

[0077]

[0078]

[0079] Example 6

[0080] This embodiment describes the preparation of a macroporous acrylic ion exchange resin containing chelating groups based on the literature [Shanghai Resin Factory, Acrylic Ion Exchange Resin, Shanghai Chemical Industry, 1975(05), 17-22]. The synthesis method is as follows: macroporous resin white spheres with a crosslinking degree of 10% are prepared using methyl acrylate and divinylbenzene as monomers. Then, the ester (i.e., macroporous resin white spheres) is converted into amide by ammonolysis in tetraethylenepentamine to obtain ammonolysed spheres. Finally, the ammonolysed spheres and chloroacetic acid are heated in liquid alkali to dechlorinate and obtain a sodium-type macroporous acrylic ion exchange resin with iminodiacetic acid as the functional group.

[0081] 50 mL of the self-made sodium-type macroporous acrylic ion exchange resin with iminodiacetic acid as the functional group was used as the experimental resin. A 50% ethylenediamine aqueous solution was filtered using the treatment method described in Comparative Example 2, i.e., the self-made resin was first converted to the hydrogen form, then the hydrogen form was converted to the ammonium form, and the resulting ammonium-form self-made resin was used to purify the ethylenediamine aqueous solution. The conversion to the ammonium form consumed 170 mL of ethylenediamine aqueous solution, with a discharge flow rate of 1.5 BV / h. After filtering 3 L, the concentration of the effluent was 49.33%, and the metal ion content was Na: 0.32 ppb, K: 0.15 ppb, Fe: 4.34 ppb, and Cu: 0.11 ppb. These results indicate that introducing chelating groups into the macroporous acrylic ion exchange resin not only retains its excellent ability to remove alkali metal ions and its exchange capacity, but also significantly improves its ability to remove heavy metals such as iron and copper. One filtration can reduce the content of sodium, potassium, and copper ions to below 1 ppb and the iron ion content to below 5 ppb, which can meet the needs of the electronics industry for organic amine aqueous solutions with extremely low metal residues.

[0082] Chelating membranes are a type of ion exchange membrane. These polymer membranes, which selectively allow ions to pass through the solution, are commonly used in water treatment processes such as electrodialysis desalination. Cation exchange membranes utilize the property of allowing cations to migrate across the membrane to reduce the concentration of heavy metal ions in water. Pressure-driven membrane filtration technology does not require voltage or electrolysis, and can remove particulate matter or heavy metal ions, offering advantages such as simple equipment and low energy consumption. Since the exchange capacity of ion exchange membranes is typically lower than that of ion exchange resins, they are suitable for purifying organic amine aqueous solutions after ion exchange resin purification, as described in this invention.

[0083] The purification methods for organic amine aqueous solutions provided in Examples 1-6 above can be used for large-scale purification of organic amine aqueous solutions required in the field of integrated circuits. Specifically, they can be used in processes such as chip cleaning, etching, doping, and precipitation.

[0084] This invention utilizes a high-exchange-capacity acrylic ion exchange resin, which can efficiently remove most metal ion impurities. The resin cost is relatively low, making macroporous acrylic ion exchange resins significantly advantageous for purifying organic amine aqueous solutions with high alkali metal ion content. This reduces the frequency of resin regeneration or replacement, improves equipment operating efficiency, and makes it suitable for large-scale purification of organic amines. A chelating filter membrane with iminodiacetic acid and meglumine functional groups exhibits high purification efficiency for metal ion impurities such as iron and copper, which are difficult for ion exchange resins to remove. This invention combines the advantages of acrylic ion exchange resins and membrane filtration, featuring good purification effect, low resin replacement frequency, and convenient filter replacement. It can stably prepare organic amine aqueous solutions with extremely low metal ion impurity content on a large scale, essentially without changing the concentration of the organic amine aqueous solution. It can also purify high-concentration organic amine aqueous solutions, providing a simple, high-capacity, and economical method for purifying organic amine aqueous solutions.

[0085] The above description of the embodiments is only for the purpose of helping to understand the method and core idea of ​​the present invention. It should be noted that those skilled in the art can make several improvements and modifications to the present invention without departing from the principle of the present invention, and these improvements and modifications also fall within the scope of protection of the claims of the present invention.

Claims

1. A method for purifying an aqueous solution of an organic amine, characterized in that, Includes the following steps: S01: Convert the initial acrylic ion exchange resin to the hydrogen form; convert the obtained hydrogen form acrylic ion exchange resin to the ammonium form; the skeleton of the initial acrylic ion exchange resin is a macroporous resin of polyacrylate, the functional group is carboxyl group, and the particle size distribution is 300-1600μm. S02: The obtained ammonium-type acrylic ion exchange resin is used to purify the aqueous solution of the organic amine to be purified once to obtain the first solution; the aqueous solution of the organic amine to be purified is selected from one or more of the following: ammonia, methylamine, dimethylamine, trimethylamine, ethylamine, diethylamine, propylamine, dipropylamine, isopropylamine, diisopropylamine, butylamine, isobutylamine, tert-butylamine, ethylenediamine, diethylenetriamine, pentamethyldiethylenetriamine, triethylenetetramine, ethanolamine, diethanolamine, triethanolamine, N-methylethanolamine, N-methyldiethanolamine, isopropanolamine, diisopropanolamine, 2-amino-2-methylpropanol, and hydroxyethylethylenediamine. S03: The first liquid is purified a second time using a chelating filter membrane to remove almost all or part of the metal ions in the organic amine aqueous solution to be purified, resulting in a second liquid; the chelating filter membrane is a modified ultra-high molecular weight polyethylene membrane, the functional groups of which include iminodiacetic acid and meglumine, and the chelating filter membrane is loaded in a capsule filter made of high-density polyethylene.

2. The purification method according to claim 1, characterized in that, In step S01, the process of converting to the hydrogen form is as follows: the initial acrylic ion exchange resin is soaked in an acid solution with a concentration of 2-10 BV and 2-20% for 12-48 hours, the acid solution is discharged at a rate of 1-3 BV / h, and after the acid solution is discharged, it is rinsed with ultrapure water at a rate of 10-20 BV / h; the acid solution is selected from at least one of analytical grade or electronic grade hydrochloric acid, sulfuric acid, phosphoric acid, and nitric acid.

3. The purification method according to claim 1, characterized in that, In step S01, the process of converting to the ammonium form is as follows: soaking the hydrogen-form acrylic ion exchange resin in an alkaline solution of 1.5-2 BV for 12-48 hours, and discharging the alkaline solution at a rate of 1-3 BV / h; the alkaline solution is an aqueous solution of the organic amine to be purified.

4. The purification method according to claim 1, characterized in that, In step S02, the first purification process is as follows: the ammonium-type acrylic ion exchange resin obtained in step S01 is soaked in the organic amine aqueous solution to be purified for 0.5-1h, and the organic amine aqueous solution after the first purification is discharged at a rate of 1-20 BV / h; in step S03, during the second purification process, the filtration flow rate of the first liquid is 1-200 mL / min.

5. The application of the purification method of the organic amine aqueous solution according to any one of claims 1-4 in the field of integrated circuits.

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