Process for purifying silicon-containing n-methylpyrrolidone

Abstract

This invention discloses a purification method for silicon-containing N-methylpyrrolidone, comprising: using silicon-containing industrial-grade N-methylpyrrolidone as raw material, sequentially performing dehydration, particle removal, organic impurity removal, treatment with a cation exchange resin capable of dissociating hydrogen ions, treatment with a carbon remover, flocculation with an anionic flocculant, treatment through a reverse osmosis membrane, treatment with an anion exchange resin capable of dissociating basic groups, treatment with a cation exchange resin capable of dissociating hydrogen ions, and filtration with a nanoscale filter cartridge; the N-methylpyrrolidone product prepared by this invention has a weight content ≥99.95%, color APHA <5, moisture ≤50ppm, Si ≤50ppt, and dust particles (>0.2μm) <200pcs / mL, meeting the requirements of semiconductor device manufacturing processes, easily achieving continuous operation, safe operation, stable product quality, and suitable for industrialization.

Description

Technical Field

[0001] This invention relates to the field of ultra-high purity reagent purification technology, specifically to a purification method for silicon-containing N-methylpyrrolidone. Background Technology

[0002] As wafer sizes continue to increase in semiconductor manufacturing, chip integration becomes increasingly sophisticated, leading to ever-higher demands for high-purity solvents. Ultra-high purity reagents are crucial raw materials in integrated circuit manufacturing. Among them, N-methylpyrrolidone (NMP) is an important organic solvent, primarily used as a solvent and stripping agent for PI (polyimide) adhesives in the panel and semiconductor industries.

[0003] Currently, the preparation of N-methylpyrrolidone typically employs silicon-containing support materials for catalyst loading, such as mesoporous silica and diatomaceous earth. Some catalysts even contain silicon themselves, such as silica-alumina, silica gel, and silica-magnesium oxide catalysts. This results in the presence of silicon in the prepared N-methylpyrrolidone to varying degrees. With increasingly stringent requirements in the semiconductor industry, silicon can potentially affect the conductivity of subsequent processes, posing a significant risk to integrated circuits. Therefore, effective silicon removal has become an urgent task. However, current purification methods for N-methylpyrrolidone primarily focus on metal cations, particulate matter, and common acid anions, with little attention paid to silicon removal. Summary of the Invention

[0004] The purpose of this invention is to overcome one or more shortcomings of the prior art and provide a purification method for silicon-containing N-methylpyrrolidone that can significantly reduce silicon content.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A method for purifying silicon-containing N-methylpyrrolidone, the method comprising:

[0007] (1) Using silicon-containing industrial-grade N-methylpyrrolidone as raw material, the silicon-containing industrial-grade N-methylpyrrolidone is subjected to dehydration, particle removal and organic impurity removal in sequence;

[0008] (2) The N-methylpyrrolidone treated in step (1) is treated with a cation exchange resin that can dissociate hydrogen ions. The pH value of the system is adjusted by the dissociated hydrogen ions to remove cationic impurities, including silicon cations.

[0009] (3) Use a decarbonator with nitrogen or inert gas to treat N-methylpyrrolidone after step (2) to remove some impurities, including carbonate and carbon dioxide.

[0010] (4) Add flocculant to N-methylpyrrolidone after treatment in step (3) for flocculation;

[0011] (5) The N-methylpyrrolidone treated in step (4) is processed through a reverse osmosis membrane to remove flocculants and some impurities, including silicon cations.

[0012] (6) The N-methylpyrrolidone treated in step (5) is treated with an anion exchange resin that can dissociate basic groups. The pH value of the system is adjusted by the dissociated basic groups to remove anionic impurities including silicon anions.

[0013] (7) The N-methylpyrrolidone treated in step (6) is treated with a cation exchange resin that can dissociate hydrogen ions;

[0014] (8) The N-methylpyrrolidone treated in step (7) is filtered using a nano-scale filter cartridge.

[0015] According to some preferred aspects of the present invention, in step (1), the dehydration is carried out by multi-stage distillation, with the distillation pressure controlled at 0.005-0.25 MPa, the reflux ratio at 1-5, the distillation temperature at 110-180℃, and the number of trays at 12-16.

[0016] More preferably, the multi-stage distillation includes sequentially performed first-stage vacuum distillation, second-stage vacuum distillation, atmospheric distillation, and third-stage vacuum distillation;

[0017] Preferably, in the first-stage vacuum distillation, the number of trays is 12-14, the feed tray is the 8th-9th stage, the reflux ratio is 3-5, the distillation temperature is 160-180℃, and the distillation pressure is controlled at 0.01-0.1MPa;

[0018] Preferably, in the two-stage vacuum distillation, the number of trays is 12-14, the feed tray is the 6th-7th stage, the reflux ratio is 1.5-3, the distillation temperature is 130-150℃, and the distillation pressure is controlled at 0.01-0.1MPa;

[0019] Preferably, in the atmospheric distillation, the number of trays is 12-14, the feed tray is the 8th-9th stage, the reflux ratio is 3-5, the distillation temperature is 160-180℃, and the distillation pressure is controlled at 0.05-0.15MPa;

[0020] Preferably, in the three-stage vacuum distillation, the number of trays is 12-14, the feed tray is the 5th-6th stage, the reflux ratio is 1-1.5, the distillation temperature is 110-130℃, and the distillation pressure is controlled at 0.01-0.1MPa.

[0021] According to some specific aspects of the present invention, in step (1), the water content in the dehydrated N-methylpyrrolidone is controlled to be below 50 ppm.

[0022] According to some preferred and specific aspects of the present invention, in step (1), the particle removal employs a micron-sized filter element; preferably, the material of the micron-sized filter element is polytetrafluoroethylene.

[0023] According to some preferred and specific aspects of the present invention, in step (1), the particle removal is carried out by filtering with filter cartridges with particle sizes of 3-5 μm and 1-2 μm in sequence.

[0024] According to some preferred aspects of the present invention, in step (1), the removal of organic impurities is performed using a macroporous adsorption resin whose skeleton is acrylic.

[0025] In some embodiments of the present invention, in step (1), the macroporous adsorption resin is preferably selected from Seplite LSA-5BG, Amberlite XAD4, etc.

[0026] According to some preferred and specific aspects of the present invention, in step (2), the cation exchange resin capable of dissociating hydrogen ions is a weakly acidic cation exchange resin; preferably, the weakly acidic cation exchange resin is one or a combination selected from Amberlite HPR8300H cation exchange resin, Amberlite IRC76CRF cation exchange resin, and Zhengguang 116 cation exchange resin.

[0027] According to some preferred and specific aspects of the present invention, in step (7), the cation exchange resin capable of dissociating hydrogen ions is a weakly acidic cation exchange resin; preferably, the weakly acidic cation exchange resin is AmberliteIRC83H cation exchange resin.

[0028] According to some preferred and specific aspects of the present invention, in step (6), the anion exchange resin capable of dissociating basic groups is a weakly basic anion exchange resin; preferably, the weakly basic anion exchange resin is Amberlite IRA67 anion exchange resin and / or Zhengguang D301 anion exchange resin.

[0029] According to some preferred aspects of the present invention, in step (3), during the process of using a decarbonizer with nitrogen or inert gas, nitrogen or inert gas is introduced from the bottom of the decarbonizer and flows upward as the mobile phase, while N-methylpyrrolidone treated in step (2) is introduced from the top of the decarbonizer and flows downward.

[0030] According to some preferred aspects of the invention, in step (4), the flocculant is polyacrylamide.

[0031] Further, in step (4), the amount of flocculant added is 1-10 ppm, which can be 2 ppm, 3 ppm, 4 ppm, 5 ppm, 6 ppm, 7 ppm, 8 ppm, 9 ppm, etc.

[0032] According to one specific aspect of the present invention, the flocculant is anionic polyacrylamide.

[0033] According to some preferred and specific aspects of the invention, in step (5), the reverse osmosis membrane is a modified polyimide membrane, which includes Evonik T2 DuraMem.

[0034] According to some preferred and specific aspects of the present invention, in step (8), the material of the nanoscale filter element is polytetrafluoroethylene.

[0035] In some preferred embodiments of the present invention, in step (8), filtration is performed using filter elements with pore sizes of 35-45nm, 16-25nm, 6-15nm, and 1-5nm respectively.

[0036] In one specific embodiment of the present invention, the purification method for silicon-containing N-methylpyrrolidone adopts the following implementation method:

[0037] (a) Dehydration: Silicon-containing industrial-grade NMP raw material is dehydrated by four-stage distillation (low-boiling-point organic impurities can also be removed during the dehydration process). The moisture content in the dehydrated NMP is controlled below 50 ppm.

[0038] (b) Particle treatment: After dehydration, the NMP solution is filtered through a filter cartridge, generally using PTFE filter cartridges with pore sizes of 3μm and 1μm in sequence;

[0039] (c) Organic impurity treatment: The NMP solution, which has been pre-treated by the filter element, enters the macroporous adsorption resin for partial removal of organic impurities;

[0040] (d) Cation removal: The NMP solution after treatment with macroporous adsorption resin is passed through a cation exchange resin that can dissociate hydrogen ions for cation removal.

[0041] (e) Decarbonator: NMP that has undergone cation removal treatment is decarbonated to remove carbonate and carbon dioxide;

[0042] (f) Flocculant: The NMP after carbonate removal is treated with polyacrylamide flocculant to remove impurities including silicon;

[0043] (g) Reverse osmosis: Using reverse osmosis membranes to remove flocculants and silica impurities;

[0044] (h) Anion removal: Anion exchange resins capable of dissociating basic groups are used to remove anionic impurities, including silicate anions.

[0045] (i) Reforming: The NMP solution, which has been deionized to remove anionic impurities including silicate anions, is reformed using a cation exchange resin capable of dissociating hydrogen ions.

[0046] (j) Particle control: Finally, the NMP solution is passed through filter cartridges with pore sizes of 40nm, 20nm, 10nm and 5nm in sequence to obtain the final NMP product.

[0047] Due to the application of the above technical solution, the present invention has the following advantages compared with the prior art:

[0048] The present invention is based on the fact that existing purification methods for N-methylpyrrolidone do not involve the removal of silicon, which limits the use of silicon-containing N-methylpyrrolidone in semiconductor manufacturing processes.

[0049] Extensive experiments and research have revealed that silicon exists in N-methylpyrrolidone in a complex manner, not entirely in particulate form, but also in forms containing silicon anions and silicon cations. However, practical experience has shown that conventional particle filtration and ion exchange using anion and cation exchange resins have limited silicon removal capabilities and cannot meet the desired requirements.

[0050] After further research, the inventors believe that the reason why the silicon removal effect is limited is that the N-methylpyrrolidone solution itself is weakly alkaline, and conventional removal methods do not necessarily lead to the control of the pH value of the solution system, which makes it difficult for some silicon to be effectively removed during particle filtration and ion exchange.

[0051] During practice, it was unexpectedly discovered that shifting the weakly alkaline N-methylpyrrolidone solution towards acidity (i.e., lowering the pH) maximizes the activation of cations in the system, making it easier to remove silicon-containing cations. After removing silicon-containing cations, shifting the solution towards alkalinity further activates anions, making it easier to remove silicon-containing anions. However, if the pH of the inherently weakly alkaline N-methylpyrrolidone solution is not changed, and silicon-containing anions are removed first under alkaline conditions, followed by pH adjustment to remove silicon-containing cations under acidic conditions, this approach is actually detrimental to the activation of cations and anions, making it difficult to maximize removal. Furthermore, this invention adds a carbon remover and flocculant treatment between cation exchange and anion exchange, which not only enhances the removal of silicon-containing cations but also lays the microenvironmental foundation for the subsequent removal of silicon-containing anions by adjusting the pH value. Simultaneously, since the removal of silicon-containing anions occurs after the removal of silicon-containing cations, the pH environment of the system tends towards alkalinity. Further, by setting a cation exchange resin capable of dissociating hydrogen ions for reforming before filtration by the nano-scale filter element, the pH environment of the system is regulated. This removes even smaller amounts of cations and allows the nano-scale filter element to function better, improving the purity of the system.

[0052] Instruction manual illustrations

[0053] Figure 1 This is a process flow diagram used in the embodiments of the present invention. Detailed Implementation

[0054] The above-mentioned solution will be further described below with reference to specific embodiments; it should be understood that these embodiments are used to illustrate the basic principles, main features and advantages of the present invention, and the present invention is not limited to the scope of the following embodiments; the implementation conditions used in the embodiments can be further adjusted according to specific requirements, and the implementation conditions not specified are usually the conditions in conventional experiments.

[0055] Unless otherwise specified in the following examples, all raw materials can be obtained from commercial sources or prepared by conventional methods in the art.

[0056] The test results of the silicon-containing industrial-grade N-methylpyrrolidone used in the following examples and comparative examples are shown in Table 1 below:

[0057] Table 1

[0058] project Test results Silicon (ppb) 1.756 Sodium (ppb) 25.7 Potassium (ppb) 35.4 Calcium (ppb) 6.25 Magnesium (ppb) 0.4 Aluminum (ppb) 0.81 Iron (ppb) 4.25 Copper (ppb) 1.05 Zinc (ppb) 1.36

[0059] Example 1

[0060] This example provides a method for purifying silicon-containing N-methylpyrrolidone, the process flow of which is as follows: Figure 1 As shown, the purification method includes the following steps:

[0061] (a) Quadruple distillation

[0062] Using silicon-containing industrial-grade N-methylpyrrolidone (N-methylpyrrolidone content approximately 99%) as raw material, the distillation process proceeds at a flow rate of 100 L / h through a single-stage distillation column (12 trays, feed tray 8, reflux ratio 3, feed temperature 170℃, pressure 0.05 MPa); a second-stage distillation column (12 trays, feed tray 7, reflux ratio 2, feed temperature 140℃, pressure 0.05 MPa); a third-stage distillation column (12 trays, feed tray 8, reflux ratio 3, feed temperature 170℃, pressure 0.1 MPa); and a fourth-stage distillation column (12 trays, feed tray 6, reflux ratio 1, feed temperature 120℃, pressure 0.05 MPa).

[0063] (b) Particle pretreatment

[0064] The N-methylpyrrolidone obtained after four-stage distillation was passed sequentially through polytetrafluoroethylene filter elements with pore sizes of 3μm and 1μm to pretreat the particles at a flow rate of 80L / h and a pressure of 0.12MPa.

[0065] (c) Macroporous adsorption resin treatment

[0066] After the particles were initially treated, the organic impurities were initially treated with macroporous adsorption resin (Seplite LSA-5BG, purchased from Xi'an Lanxiao) at a flow rate of 60 L / h and a pressure of 0.1 MPa.

[0067] (d) Treatment with cation exchange resins capable of dissociating hydrogen ions

[0068] N-methylpyrrolidone, after being treated with macroporous adsorption resin, was passed through a cation exchange resin capable of dissociating hydrogen ions (specifically Amberlite HPR8300H, purchased from Shizhong Mingzhi Chemical (Shanghai)) to remove cations at a flow rate of 80 L / h and a pressure of 0.1 MPa.

[0069] (e) Decarbonizer treatment

[0070] N-methylpyrrolidone after cation removal treatment is passed through a decarbonator to remove carbonate and carbon dioxide. Nitrogen gas (flow rate 600 L / h) is used as the mobile phase and is introduced from the bottom of the decarbonator from bottom to top. N-methylpyrrolidone treated with cation exchange resin (flow rate 80 L / h) is introduced from the top of the decarbonator from top to bottom.

[0071] (f) Flocculation treatment

[0072] Anionic polyacrylamide flocculant (addition amount of 5 ppm, purchased from Jinan Zhongbei Fine Chemical Co., Ltd., brand name PAM800-2500) was added to N-methylpyrrolidone that had been treated by a decarbonizer for flocculation treatment.

[0073] (g) Reverse osmosis treatment

[0074] After flocculation, reverse osmosis treatment is carried out at a flow rate of 60 L / h and a pressure of 0.8 MPa. The reverse osmosis membrane used is the Evonik T2 DuraMem modified polyimide membrane.

[0075] (h) Treatment with anion exchange resins capable of dissociating basic groups

[0076] The N-methylpyrrolidone after reverse osmosis was treated with an anion exchange resin (specifically Amberlite IRA67, purchased from Shanghai Chengli Environmental Protection Technology) that can dissociate basic groups, at a flow rate of 40 L / h and a pressure of 0.12 MPa.

[0077] (i) Treatment with cation exchange resins capable of dissociating hydrogen ions

[0078] The N-methylpyrrolidone treated with anion exchange resin was reformed using a cation exchange resin (specifically Amberlite IRC83H, purchased from Tianjin Shuanglian Technology) capable of dissociating hydrogen ions, at a flow rate of 60 L / h and a pressure of 0.12 MPa.

[0079] (j) Nanoscale filter cartridge treatment

[0080] Finally, the product is filtered through polytetrafluoroethylene filter elements with pore sizes of 40nm, 20nm, 10nm, and 5nm, at a flow rate of 50L / h and a pressure of 0.12MPa, to obtain the final N-methylpyrrolidone product.

[0081] Example 2

[0082] Increase the feed inlet temperature of each stage of the four-stage distillation process by 10°C.

[0083] Example 3

[0084] Reduce the feed inlet temperature of each stage of the four-stage distillation process by 10°C.

[0085] Example 4

[0086] The flow rate at each stage of the purification process will be increased by 20%.

[0087] Example 5

[0088] The flow rate at each stage of the purification process will be reduced by 20%.

[0089] Example 6

[0090] Replace the cation exchange resin used in step (d) with "DuPont Amberlite HPR1300H strong acid cation exchange resin".

[0091] Comparative Example 1

[0092] The process is basically the same as in Example 1, except that process (h) is moved between process (c) and process (d), while everything else remains the same.

[0093] Comparative Example 2

[0094] It is basically the same as Example 1, except that the order of process (h) and process (i) is changed.

[0095] Comparative Example 3

[0096] It is basically the same as Example 1, except that the decarbonizer treatment (e) is omitted.

[0097] Comparative Example 4

[0098] The process is basically the same as in Example 1, except that step (f) flocculation treatment is omitted.

[0099] Performance testing

[0100] Tables 2-3 below show the test results of the N-methylpyrrolidone products obtained in Examples 1-6 and Comparative Examples 1-4, respectively.

[0101] In the following tests, the content of elements such as silicon and sodium was analyzed using inductively coupled plasma mass spectrometry (ICP-MS).

[0102] Table 2

[0103]

[0104] Table 3

[0105] project Comparative Example 1 Comparative Example 2 Comparative Example 3 Comparative Example 4 Silicon (ppb) 0.640 0.417 0.175 0.533 Sodium (ppb) 0.344 0.296 0.229 0.217 Potassium (ppb) 0.689 0.674 0.751 0.726 Calcium (ppb) 0.931 0.867 1.246 1.237 Magnesium (ppb) 0.024 0.036 0.048 0.059 Aluminum (ppb) 0.116 0.118 0.282 0.237 Iron (ppb) 0.246 0.212 0.391 0.332 Copper (ppb) 0.035 0.048 0.108 0.127 Zinc (ppb) 0.071 0.097 0.316 0.327

[0106] The above embodiments are only for illustrating the technical concept and features of the present invention, and are intended to enable those skilled in the art to understand the content of the present invention and implement it accordingly. They should not be construed as limiting the scope of protection of the present invention. All equivalent changes or modifications made in accordance with the spirit and essence of the present invention should be covered within the scope of protection of the present invention.

[0107] The endpoints and any values ​​of the ranges disclosed herein are not limited to the precise ranges or values, and these ranges or values ​​should be understood to include values ​​close to these ranges or values. For numerical ranges, the endpoint values ​​of the various ranges, the endpoint values ​​of the various ranges and individual point values, and individual point values ​​can be combined with each other to obtain one or more new numerical ranges, which should be considered as specifically disclosed herein.

Claims

1. A purification method of silicon-containing N-methylpyrrolidone, characterized by, The purification method comprises: (1) taking industrial-grade N-methyl pyrrolidone containing silicon as raw material, and sequentially performing dehydration, particle removal and organic impurity removal on the industrial-grade N-methyl pyrrolidone containing silicon; The dehydration is performed by using a multi-stage rectification mode, the rectification pressure is controlled at 0.005-0.25 MPa, the reflux ratio is 1-5, the rectification temperature is 110-180℃, and the number of tower plates is 12-16; (2) treating the N-methyl pyrrolidone treated in step (1) by using a cation exchange resin capable of dissociating hydrogen ions to remove cation impurities including silicon-containing cations by adjusting the pH value of the system through the dissociated hydrogen ions; wherein the cation exchange resin capable of dissociating hydrogen ions is a weak acid cation exchange resin, and the weak acid cation exchange resin is one or a combination selected from Amberlite HPR8300H cation exchange resin, Amberlite IRC76CRF cation exchange resin and Zhengguang 116 ion exchange resin; (3) treating the N-methyl pyrrolidone treated in step (2) by using a carbon remover blowing nitrogen or inert gas to remove part of impurities including carbonate and carbon dioxide; (4) adding a flocculating agent to the N-methyl pyrrolidone treated in step (3) for flocculation; (5) treating the N-methyl pyrrolidone treated in step (4) by using a reverse osmosis membrane to remove part of impurities including the flocculating agent and silicon-containing cations; (6) treating the N-methyl pyrrolidone treated in step (5) by using an anion exchange resin capable of dissociating basic groups to remove anion impurities including silicon-containing anions by adjusting the pH value of the system through the dissociated basic groups; wherein the anion exchange resin capable of dissociating basic groups is a weak basic anion exchange resin, and the weak basic anion exchange resin is Amberlite IRA67 anion exchange resin and / or Zhengguang D301 anion exchange resin; (7) treating the N-methyl pyrrolidone treated in step (6) by using a cation exchange resin capable of dissociating hydrogen ions; wherein the cation exchange resin capable of dissociating hydrogen ions is a weak acid cation exchange resin, and the weak acid cation exchange resin is Amberlite IRC83H cation exchange resin; (8) filtering the N-methyl pyrrolidone treated in step (7) by using a nanometer filter element.

2. The purification method of silicon-containing N-methylpyrrolidone according to claim 1, characterized by, The multi-stage rectification comprises sequentially performing primary reduced-pressure rectification, secondary reduced-pressure rectification, normal-pressure rectification and tertiary reduced-pressure rectification.

3. The purification method of silicon-containing N-methylpyrrolidone according to claim 2, characterized by, In the primary reduced-pressure rectification, the number of tower plates is 12-14, the tower plate of the feed inlet is the 8th-9th stage, the reflux ratio is 3-5, the rectification temperature is 160-180℃, and the rectification pressure is controlled at 0.01-0.1 MPa; and / or, in the secondary reduced-pressure rectification, the number of tower plates is 12-14, the tower plate of the feed inlet is the 6th-7th stage, the reflux ratio is 1.5-3, the rectification temperature is 130-150℃, and the rectification pressure is controlled at 0.01-0.1 MPa; And / or, in the normal pressure rectification, the number of plates is 12-14, the plate of feed inlet is the 8th-9th stage, the reflux ratio is 3-5, the rectification temperature is 160-180℃, and the rectification pressure is controlled at 0.05-0.15 MPa. And / or, in the three-stage reduced pressure rectification, the number of plates is 12-14, the plate of feed inlet is the 5th-6th stage, the reflux ratio is 1-1.5, the rectification temperature is 110-130℃, and the rectification pressure is controlled at 0.01-0.1 MPa.

4. The purification method of silicon-containing N-methylpyrrolidone according to claim 1, characterized by, In step (1), the particle removal is performed by using a micron filter.

5. The purification method of silicon-containing N-methylpyrrolidone according to claim 4, characterized by, The micron filter is made of polytetrafluoroethylene.

6. The purification process of silicon-containing N-methylpyrrolidone according to claim 1, characterized in that, In step (1), the particle removal is performed by using filters with particle sizes of 3-5 μm and 1-2 μm in sequence; and / or, in step (1), the organic impurity removal is performed by using a macroporous adsorption resin with an acrylic skeleton.

7. The purification method of silicon-containing N-methylpyrrolidone according to claim 1, characterized by, In step (3), during the treatment by using a carbon remover with nitrogen or inert gas, nitrogen or inert gas is used as the mobile phase to be introduced from the lower part of the carbon remover and flow from bottom to top, and the N-methyl pyrrolidone treated in step (2) is introduced from the upper part of the carbon remover and flow from top to bottom.

8. The purification process of silicon-containing N-methylpyrrolidone according to claim 1, characterized in that, In step (4), the flocculating agent is polyacrylamide; and / or, in step (4), the addition amount of the flocculating agent is 1-10 ppm.

9. The purification process of silicon-containing N-methylpyrrolidone according to claim 1, characterized in that, In step (5), the reverse osmosis membrane is a modified polyimide membrane, which includes the Swagelok T2 DuraMem.

10. The purification process of silicon-containing N-methylpyrrolidone according to claim 1, characterized in that, In step (8), the material of the nanometer filter is polytetrafluoroethylene; and / or, in step (8), the filtration is performed by using filters with pore sizes of 35-45 nm, 16-25 nm, 6-15 nm and 1-5 nm in sequence.

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