A method for purifying electronic grade NMP

Abstract

A method for purifying electronic-grade NMP comprises the following steps: mixing metal ions and organic ligands in water or an organic solvent in a certain proportion; reacting the obtained mixture for a certain time under a certain atmosphere, temperature and pressure using one or more of the methods such as hydrothermal method, microwave method and radiation synthesis to obtain MOF; filling one or more of the obtained MOF materials in an adsorption column, injecting NMP into the adsorption column at a certain flow rate and staying for a certain time; collecting the treated NMP solution at the outlet of the adsorption column to obtain purified NMP. The present invention can achieve efficient removal of most metal impurities in the NMP solution, and can obtain ≥99.999% electronic-grade NMP products.

Description

Technical Field

[0001] The invention belongs to the technical field of chemical engineering, and in particular relates to a method for purifying electronic-grade NMP and an adsorption material for removing metal impurities. Background Art

[0002] N-methylpyrrolidone (NMP) has high chemical stability, low toxicity, low volatility, and biodegradability. It is widely used as an excellent organic solvent. NMP was first used in petrochemicals, pesticides, coatings and other fields, but as the purity of NMP continues to increase, electronic-grade NMP is used as a semiconductor solvent, lithium battery, precision instrument and other electronic products production and maintenance cleaning agent, and disk photoresist stripping liquid and other high-end fields due to its high purity (usually above 99.8%) and low impurities (such as metal ion content at the μg / L level). The purity and impurity content of electronic-grade NMP have a crucial impact on the yield, electrical performance and reliability of integrated circuits. Most metal impurity content is required to be controlled at the 1μg / kg level, and even some key metal impurity content is required to be controlled at the 0.1μg / kg level.

[0003] In the prior art, NMP is produced by conventional distillation. Although distillation can improve the quality purity of NMP to a certain extent, there are still a certain amount of impurities, especially metal impurities, which are the main cause of semiconductor leakage and other problems. The metal impurities in NMP mainly come from: 1. Trace metal impurities introduced in the production environment and manufacturing process; 2. Metal impurities brought by people during transportation and storage; 3. Metal pollution introduced by the external environment during use. These metal impurities cannot be separated by conventional distillation, and purification is very difficult, especially for the preparation and production of electronic grade NMP (99.99%), which is a severe challenge to its system and process design requirements.

[0004] There is a method of using ion exchange resin to adsorb and separate metal impurities in NMP in the prior art. Macroporous and strong base anion resins are used to remove metal impurities in NMP by surface chemical adsorption. However, the surface groups of ion resins are single and the pore structure is uncontrollable, so the adsorption efficiency is low and the adsorption effect is poor. Therefore, the controllability of the pore structure and surface functional groups of the adsorption material is the key to improving the adsorption and removal effect of metal impurities in NMP.

[0005] Metal-organic framework (MOF) refers to a crystalline porous material with a periodic network structure formed by self-assembly of transition metal ions and organic ligands. Through the regulation of metal ions, organic ligands and reaction conditions, MOF materials with advantages such as high porosity, low density, large specific surface area, regular pores, adjustable pore size, topological structure diversity and tailorability, and adjustable surface functional groups can be obtained. The pore structure formed by the periodic network structure inside the MOF material has been widely used in fields such as gas storage and separation. Summary of the invention

[0006] In order to solve the problems of the existing NMP purification technology, the purpose of the present invention is to provide a method for purifying electronic grade NMP and an adsorbent material for removing metal impurities, which can achieve efficient adsorption of metal impurities in NMP distillation products.

[0007] The present invention is achieved through the following technical solutions:

[0008] The invention provides a method for purifying electronic-grade NMP and an adsorption material for removing metal impurities. MOF material is filled in an adsorption column, NMP is injected into the adsorption column at a certain flow rate and stays for a certain time, and the NMP solution after adsorption is collected to obtain electronic-grade NMP.

[0009] The MOF material is obtained by mixing metal ions and imidazole ligands in an organic solvent and reacting them for a certain time under a certain atmosphere, temperature and pressure using one or more of a hydrothermal method, a microwave method (microwave frequency range 200~1500 W), or a ball milling method (ball milling rate range 30 rmp~1500 rmp).

[0010] The metal ions include any one of zinc ions, iron ions, cobalt ions, nickel ions and ruthenium ions.

[0011] The imidazole ligands include any one or a mixture of imidazole, imidazoline, biimidazole, imidazoline, 4-imidazole acrylic acid, 4-phenylimidazole, 5,6-dimethylbenzimidazole, 4-nitroimidazole, dimethylimidazole and imidazole derivatives.

[0012] The solvent includes any one or a mixture of formamide, benzamide, N-methylformamide, N-ethylformamide, 2-aminobenzamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylethylenediamine, N,N-diethylformamide, triethylamine, n-hexane, methanol, and acetic acid.

[0013] The mass ratio of the metal ion, the organic ligand and water or the organic solvent is (1-10): (0.1-1): (10-20).

[0014] The MOF synthesis method is one or more of a hydrothermal method, a microwave method, a radiation synthesis method and the like.

[0015] The hydrothermal method is to mix metal ions and imidazole ligands with an organic solvent, and then carry out a hydrothermal reaction for 1h-50h in an inert atmosphere in a closed environment of 100-300°C and -10 MPa to 1000 MPa to obtain a product.

[0016] The microwave method is to mix metal ions and imidazole ligands with an organic solvent, and then carry out microwave reaction at 0°C to 300°C for 1h to 50h in air or an inert atmosphere to obtain a product, wherein during the microwave reaction, the microwave frequency range is 200 to 1500 W, and the atmosphere is air or an inert gas (one or a mixture of nitrogen and argon).

[0017] The ball milling method is to mix metal ions, imidazole ligands and organic solvents, and then carry out the ball milling in air or an inert atmosphere at a temperature of 0°C to 300°C and a pressure of -10 MPa to 20 MPa. The reaction time is 1 min to 50 h, and the ball milling rate range is 30 rmp to 1500 rmp. The atmosphere is air or an inert gas (one or a mixture of nitrogen and argon).

[0018] The specifications of the adsorption column are: 100 mL~10 L.

[0019] The loaded product includes one or more of the MOF materials synthesized in the above step (2), and the loading method is mixed loading, and the mixing ratio of the MOF materials is (1~10):(1~10):(1~10) by volume.

[0020] The metal impurity content in NMP at the inlet of the adsorption column is 1 ppb ~5000 ppm.

[0021] The injection flow rate of NMP is 0.1 mL / min to 1 L / min.

[0022] The residence time of NMP in the adsorption column is 10 sec~100 h.

[0023] The total flow rate of NMP is 0.01~100 t / h.

[0024] The purified NMP reaches electronic grade standards, with a purity of ≥99.999%.

[0025] The benefit of the present invention is that, through the regulation of metal ions, organic ligands and reaction conditions, a MOF material with a micropore-mesopore-macroporous multi-level pore structure, a high specific surface area with adjustable pore structure, a diverse morphology structure and adjustable surface functional groups is obtained, and the metal ions in NMP are targetedly adsorbed by using its pore structure and surface functional groups. The present invention can achieve efficient removal of most metal impurities in NMP solution, and can obtain ≥99.999% electronic grade NMP products. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is a scanning electron microscope image of the Zn-MOF material 1 in Example 1 of the present invention.

[0027] Figure 2 This is a scanning electron microscope image of the Zn-MOF material 2 in Example 1 of the present invention.

[0028] Figure 3 This is a scanning electron microscope image of Co-MOF material 3 in Example 1 of the present invention.

[0029] Figure 4 This is a scanning electron microscope image of the Fe-MOF material 4 in Example 1 of the present invention. DETAILED DESCRIPTION

[0030] A method for purifying electronic grade NMP and an adsorbent material for removing metal impurities, comprising the following steps: A method for purifying electronic grade NMP and an adsorbent material for removing metal impurities, wherein metal ions and organic ligands are uniformly mixed in a certain proportion in water or an organic solvent; the obtained mixture is reacted for a certain time under a certain atmosphere, temperature, and pressure by one or more of the methods such as hydrothermal method, microwave method, and radiation synthesis to obtain MOF; one or more of the obtained MOF materials are filled in an adsorption column, and NMP is injected into the adsorption column at a certain flow rate and stays for a certain time; the NMP solution after treatment is collected at the outlet of the adsorption column to obtain purified NMP. The present invention can achieve efficient removal of most metal impurities in the NMP solution, and can obtain ≥99.999% electronic grade NMP products.

[0031] Example 1

[0032] Preparation of MOF materials:

[0033] Preparation of Zn-MOF material: (1) Dissolve 10 g of zinc nitrate in water and add it to imidazole and acetic acid solution in a mass ratio of 1:0.2:2. Protect the environment with nitrogen and carry out hydrothermal reaction at 200 °C and 10 MPa for 180 min to obtain Zn-MOF material 1.

[0034] (2) Zinc nitrate and imidazole ligands were dissolved in N,N-dimethylformamide and N,N-diethylformamide in a mixing ratio of 2:4:15:3. The solution was heated to 220°C in a hydrothermal reactor and reacted for 48 h in an argon-protected environment to obtain Zn-MOF material 2.

[0035] Preparation of Co-MOF material: Cobalt nitrate was dissolved in a methanol solution of 2-methylimidazole, with a mass ratio of cobalt nitrate, 2-methylimidazole and methanol of 1:1.5:20. The mixture was milled at a rate of 100 rpm under air conditions for 24 h at room temperature. After centrifugation, Co-MOF material 3 was obtained.

[0036] Preparation of Fe-MOF material: Cobalt nitrate was dissolved in 2-methylimidazole and N,N-dimethylethylenediamine in a mass ratio of 3:8:100, and reacted for 10 min under a mixed atmosphere of nitrogen and argon in a volume ratio of 1:1 at a microwave frequency of 800 W. Then 100 mL of 10% ferric chloride solution was added and the microwave reaction was continued for 1.5 h at the same frequency. Fe-MOF material 4 was obtained after centrifugation.

[0037] Example 2

[0038] The Zn-MOF material 1 prepared in Example 1 was filled into a 200 mL adsorption column, and an NMP solution with a metal impurity content of 500 ppm was introduced from the inlet of the adsorption column. The injection flow rate of NMP was 1 mL / min, the residence time was 1 h, and the total flow rate of NMP was 0.1 kg / h;

[0039] The treated NMP is collected at the outlet of the adsorption column. The purified NMP meets the electronic grade standard with a purity of ≥99.999%.

[0040] Example 3

[0041] The Fe-MOF material 4 prepared in Example 1 was filled into a 500 mL adsorption column, and an NMP solution with a metal impurity content of 10 ppm was introduced from the inlet of the adsorption column. The injection flow rate of NMP was 10 mL / min, the residence time was 2 h, and the total flow rate of NMP was 1 kg / h;

[0042] The treated NMP is collected at the outlet of the adsorption column. The purified NMP meets the electronic grade standard with a purity of ≥99.999%.

[0043] Example 4

[0044] The Co-MOF material 3 prepared in Example 1 was filled into a 10 L adsorption column, and an NMP solution with a metal impurity content of 10 ppb was introduced from the inlet of the adsorption column. The injection flow rate of NMP was 50 mL / min, the residence time was 0.5 h, and the total flow rate of NMP was 0.01 kg / h;

[0045] The treated NMP is collected at the outlet of the adsorption column. The purified NMP meets the electronic grade standard with a purity of ≥99.999%.

[0046] Example 5

[0047] The Zn-MOF material 2 and the Co-MOF material 3 prepared in Example 1 were mixed at a volume ratio of 1:1:1, and then filled into a 2 L adsorption column. An NMP solution with a metal impurity content of 10 ppb was introduced from the inlet of the adsorption column. The injection flow rate of NMP was 50 mL / min, the residence time was 0.5 h, and the total flow rate of NMP was 0.01 kg / h;

[0048] The treated NMP is collected at the outlet of the adsorption column. The purified NMP meets the electronic grade standard with a purity of ≥99.999%.

[0049] Example 6

[0050] The Zn-MOF material 1, Fe-MOF material 4 and Co-MOF material 3 prepared in Example 1 were mixed in a volume ratio of 1:5:4, and filled into a 5 L adsorption column. An NMP solution with a metal impurity content of 10 ppb was introduced from the inlet of the adsorption column. The injection flow rate of NMP was 50 mL / min, the residence time was 0.5 h, and the total flow rate of NMP was 0.01 kg / h;

[0051] The treated NMP is collected at the outlet of the adsorption column. The purified NMP meets the electronic grade standard with a purity of ≥99.999%.

[0052] In summary, the method for purifying electronic-grade NMP and the adsorption material for removing metal impurities of the present invention can achieve efficient removal of most metal impurities in NMP solution, and can obtain ≥99.999% electronic-grade NMP products.

[0053] The specific embodiments described above further illustrate the objectives, technical solutions and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A method for purifying electronic grade NMP, characterized in that, The following steps are involved: The MOF material is filled in an adsorption column, NMP is injected into the adsorption column, and after retention and adsorption, the adsorbed NMP solution is collected to obtain electronic grade NMP, wherein the MOF material is prepared by a hydrothermal method after metal ions and imidazole ligands are mixed with an organic solvent, and the hydrothermal method is to mix metal ions and imidazole ligands with an organic solvent in air or an inert atmosphere, in a closed environment at 100-300°C and -10 MPa to 1000 MPa, and then perform a hydrothermal reaction for 1h to 50h to obtain a product, wherein the inert atmosphere is selected from nitrogen or argon, or a mixture of the two gases; The metal ion is selected from any one of zinc ion, iron ion, cobalt ion, nickel ion and ruthenium ion; the imidazole ligand is selected from any one of imidazole, imidazoline, biimidazole, imidazosin, 4-imidazole acrylic acid, 4-phenylimidazole, 5,6-dimethylbenzimidazole, 4-nitroimidazole and dimethylimidazole or a mixture thereof; the organic solvent is selected from any one of formamide, benzamide, N-methylformamide, N-ethylformamide, 2-aminobenzamide, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-dimethylethylenediamine, N,N-diethylformamide, triethylamine, n-hexane, methanol and acetic acid or a mixture thereof.

2. The method for purification of electronic-grade NMP according to claim 1, wherein The mass ratio of metal ion, imidazole ligand and organic solvent is (1-10): (0.1-1): (10-20).

3. The method for purification of electronic-grade NMP according to claim 1, wherein The MOF material is prepared by mixing metal ions and imidazole ligands with an organic solvent and then using a microwave method instead of a hydrothermal method. The microwave method is to mix metal ions and imidazole ligands with an organic solvent, and then carry out a microwave reaction at 0°C to 300°C for 1h-50h in air or an inert atmosphere to obtain a product. During the microwave reaction, the microwave frequency ranges from 200 to 1500 W, and the inert atmosphere is selected from nitrogen or argon, or a mixture of the two gases.

4. The method for purification of electronic-grade NMP according to claim 1, wherein The MOF material is prepared by mixing metal ions and imidazole ligands with an organic solvent and then adopting a ball milling method instead of a hydrothermal method. The ball milling method is to mix the metal ions, imidazole ligands and organic solvent in air or an inert atmosphere at a temperature of 0°C to 300°C and a pressure of -10 MPa to 20 MPa. The reaction time is 1 min to 50 h, and the ball milling rate ranges from 30 rmp to 1500 rmp. The inert atmosphere is selected from nitrogen or argon or a mixture of the two gases.

5. according to the method for purification of the electronic grade NMP described in any one of claims 1-4, it is characterized in that, The injection flow rate of NMP is 0.1 mL / min~1 L / min; the residence time of NMP in the adsorption column is 10 sec~100 h; the total flow rate of NMP is 0.01~100 t / h.

6. The method for purification of electronic-grade NMP according to claim 5, wherein The injection flow rate of NMP is 0.2mL / min~0.8L / min; the residence time of NMP in the adsorption column is 2 h; the total flow rate of NMP is 0.5~10 t / h.

7. A method for purifying electronic grade NMP, characterized in that, The electronic grade NMP is prepared by the method described in any one of claims 1 to 6, and the metal impurity content in the electronic grade NMP is 1 ppb to 5000 ppm.

8. The method for purification of electronic-grade NMP according to claim 7, wherein The metal impurity content in electronic grade NMP is 1 ppb ~1 ppm.

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