CN114181130B - Purification method of N-methyl pyrrolidone - Google Patents
Purification method of N-methyl pyrrolidone Download PDFInfo
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- C07D207/02—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom
- C07D207/18—Heterocyclic compounds containing five-membered rings not condensed with other rings, with one nitrogen atom as the only ring hetero atom with only hydrogen or carbon atoms directly attached to the ring nitrogen atom having one double bond between ring members or between a ring member and a non-ring member
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- C07D207/263—2-Pyrrolidones with only hydrogen atoms or radicals containing only hydrogen and carbon atoms directly attached to other ring carbon atoms
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Abstract
The invention provides a purification method of N-methyl pyrrolidone, which comprises the following steps: A) introducing industrial grade N-methyl pyrrolidone into a lightness-removing tower, carrying out total reflux under a reduced pressure condition, adjusting the reflux ratio after the product quality is stable, and beginning to extract the lightness-removed N-methyl pyrrolidone; B) and conveying the lightness-removed N-methyl pyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-controlled adsorption material to obtain the purified N-methyl pyrrolidone. The invention adopts a rectification coupling ion adsorption mode, adopts a light removal device to control the purity, the amine content and the moisture content of light impurities in the N-methyl pyrrolidone, and then removes metal ions in the N-methyl pyrrolidone through an adsorption system. The obtained electronic grade NMP product has purity, moisture, metal ion, organic amine and other impurities reaching the standard of high-end industry.
Description
Technical Field
The invention belongs to the technical field of organic matter purification, and particularly relates to a method for purifying N-methyl pyrrolidone.
Background
N-methyl pyrrolidone (NMP) is colorless, highly polar, chemically stable and thermally stable liquid. Meanwhile, it has the characteristics of low vapor pressure and good solubility, and can be used as an organic solvent and an extracting agent. At present, N-methyl pyrrolidone can be divided into common grade, industrial grade and electronic grade according to different product indexes, wherein the electronic grade N-methyl pyrrolidone is widely applied to high-end industries such as semiconductors, lithium batteries and the like and can be used as a semiconductor circuit board cleaning agent and a lithium battery electrolyte solvent. N-methyl pyrrolidone used in high-end industries has strict index requirements on purity, moisture, metal ions, organic amine and the like, for example, in the lithium ion battery industry, moisture in the N-methyl pyrrolidone can react with a solvent in an electrolyte to influence the activity or the service life of a lithium battery, and metal impurity ions with lower reduction potential than lithium ions can greatly reduce the reversible capacity of the lithium battery. At present, domestic electronic grade products mainly depend on import, the electronic grade NMP purification process has a technical barrier, and most domestic purification processes cannot meet the requirements of high-end industries.
There are two types of synthesis and recovery of N-methylpyrrolidone on the market. The industrial synthesis of the N-methyl pyrrolidone takes gamma-butyrolactone and methylamine as raw materials, the obtained product is purified by decompression, dehydration and distillation, and the N-methyl pyrrolidone contains part of organic ammonia, water and impurity particles; the recovered N-methyl pyrrolidone contains water, metal ions and organic impurities in large proportion.
The conventional purification method of N-methyl pyrrolidone mostly adopts a distillation process, and redundant water and metal ions in NMP are removed by continuous rectification. The U.S. Pat. No. 4, 4965370 and the like adopt a continuous rectification process to obtain a high-purity N-methylpyrrolidone product, have a good purification effect on newly synthesized NMP, but the recovered NMP is difficult to remove by single rectification; meanwhile, trace metals have sublimation volatility, trace heavy metals in the N-methylpyrrolidone volatilize along with the evaporation of materials during rectification, and cannot be removed well, so that the purity and metal ions of the NMP obtained by the process cannot meet the requirements of electronic-grade products.
Chinese patent CN 201910885485.X discloses a method for reducing metal ions and particle size in NMP by rectification combined with filtration: firstly removing water and methylamine in NMP under normal pressure, then removing bottom boiling under reduced pressure, removing high boiling under normal pressure, and removing metal ions and particles in the product by three-stage filtration. The process needs six steps to be completed, has higher requirement on equipment and increases the production cost.
Disclosure of Invention
The invention aims to provide a method for purifying N-methyl pyrrolidone, which has simple steps and high quality of purified products.
The invention provides a method for purifying N-methyl pyrrolidone, which comprises the following steps:
A) introducing industrial grade N-methyl pyrrolidone into a lightness-removing tower, and carrying out total reflux under a reduced pressure condition to obtain lightness-removed N-methyl pyrrolidone;
B) conveying the lightness-removed N-methyl pyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-controlled adsorption material to obtain purified N-methyl pyrrolidone;
the temperature control adsorption material is a heat-sensitive polymer loaded with functional groups; the thermo-responsive polymer has a structure represented by formula I:
in formula I, the ratio of n to m is 1: (1 to 9), R 1 Is an alkyl chain between C1 and C4, R 2 The thermal induction polymer is a halogen group, and the number average molecular weight of the thermal induction polymer is 11000-61000;
the functional group is monomethyl sulfide and/or long alkyl methyl sulfide.
Preferably, the purity of the N-methyl pyrrolidone fully refluxed to the side line of the light component removal tower at the tower top temperature of 45-60 ℃ and the operation pressure of 1-10 KPa is more than 99.9 percent, the water content is less than 20ppm, and the organic amine is less than 20 ppm;
after the temperature is stable, adjusting the reflux ratio to be 3, and collecting the light-weight removed N-methyl pyrrolidone at the lateral line;
preferably, the molar ratio of carboxyl end groups to methoxy groups in the thermo-responsive polymer is 1: (1-20).
Preferably, the molar ratio of the functional group to the methoxy group is 1: (1-40).
Preferably, the thermo-responsive polymer is a porous material.
Preferably, the temperature-control adsorbing material adsorbs metal ions at normal temperature, and after adsorption saturation, the temperature-control adsorbing material is washed at 45-65 ℃ to regenerate the temperature-control adsorbing material.
Preferably, the temperature-control adsorption material is prepared according to the following steps:
and (3) mixing the thermal-sensitive polymer with the precursor solution of the functional group in the presence of an initiator, and carrying to obtain the temperature-control adsorbing material.
Preferably, the temperature of the load is 20-300 ℃; the loading time is 30-370 min.
Preferably, the molar concentration of the precursor solution of the functional group is 0.5-2 mol/L;
the volume ratio of the thermo-sensitive polymer to the precursor solution of the functionalized group is 1: (0.01-0.2).
Preferably, the adsorption tower is provided with a temperature-controlled adsorption material regeneration system, and the light component removal tower is thermally coupled with the temperature-controlled adsorption material regeneration system.
The invention provides a purification method of N-methyl pyrrolidone, which comprises the following steps: A) introducing industrial grade N-methyl pyrrolidone into a lightness-removing tower, performing total reflux under the reduced pressure condition, adjusting the reflux ratio after the product quality is stable, and laterally extracting the N-methyl pyrrolidone after lightness removal; B) conveying the lightness-removed N-methyl pyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-controlled adsorption material to obtain purified N-methyl pyrrolidone; the temperature control adsorption material is a thermal induction polymer loaded with functional groups; the thermo-responsive polymer has a structure represented by formula I: in formula I, the ratio of n to m is 1: (1-9), R) 1 Is an alkyl chain between C1 and C4, R 2 The thermal induction polymer is a halogen group, and the data molecular weight of the thermal induction polymer is 11000-61000; the functional group is a thioether group; the functional group is monomethyl sulfide and/or long alkyl methyl sulfide. The invention adopts a rectification coupling ion adsorption mode, adopts a light removal device to control the purity, the amine content and the moisture content of light impurities in the N-methyl pyrrolidone, and then removes metal ions in the N-methyl pyrrolidone through an adsorption system. The obtained electronic grade NMP product has purity, moisture, metal ion, organic amine and other impurities reaching the standard of high-end industry. The adsorption material adopts an intelligent polymer system based on a thermal switch, functional groups are loaded on the surface of the polymer, residual impurities including metal ions, organic anions and particles are further removed after the NMP with the purity and moisture reaching the standard is treated and rectified, the purity of the finally obtained NMP product can reach 99.99%, the moisture is less than 50ppm, the content of single metal ions is less than 0.1ppb, the content of organic amine is less than 50ppm, and the product quality is superior to that of the existing products in the market.
Drawings
In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings used in the description of the embodiments or the prior art will be briefly described below, it is obvious that the drawings in the following description are only embodiments of the present invention, and for those skilled in the art, other drawings can be obtained according to the provided drawings without creative efforts.
FIG. 1 is a schematic diagram of a process for preparing a temperature-controlled adsorbent material according to the present invention; in FIG. 1, a single gray curve a represents a thermo-responsive polymer, and a plurality of thermo-responsive polymers in solution are in an aggregation form, in which a hydrophobic end is aggregated in an inner core and a hydrophilic end is exposed to the outside to form a bundle b, and then react with a functional group c to form a final micelle-shaped temperature-controlled adsorption material d;
FIG. 2 is a schematic view of the structure of the apparatus used for purification according to the present invention,
wherein, I is a light component removal tower, II is an adsorption tower, E-4 is a feed pump, and E-3 is a heat exchanger; e-5 is a condenser, and V-2 is a stop valve.
Detailed Description
The invention provides a method for purifying N-methyl pyrrolidone, which comprises the following steps:
A) introducing industrial grade N-methylpyrrolidone into a lightness-removing tower, and carrying out total reflux under the reduced pressure condition to obtain lightness-removed N-methylpyrrolidone;
B) conveying the lightness-removed N-methylpyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-control adsorption material to obtain purified N-methylpyrrolidone;
the temperature control adsorption material is a heat-sensitive polymer loaded with functional groups; the thermo-responsive polymer has a structure represented by formula I:
in formula I, the ratio of n to m is 1: (1 to 9), R 1 Is an alkyl chain between C1 and C4, R 2 Is a halogen radical, saidThe number average molecular weight of the thermal induction polymer is 11000-61000;
the functional group is monomethyl sulfide and/or long alkyl methyl sulfide.
As shown in figure 2, the purification device firstly feeds industrial NMP material into a lightness-removing tower through a feed pump, reduces the pressure, then raises the temperature, and starts total reflux until the purity of NMP at a side extraction opening of the lightness-removing tower reaches more than 99.9%, the moisture is less than 20ppm, and the organic amine is less than 20 ppm.
In the invention, the operating pressure of the light component removal tower is preferably 1-10 KPa, more preferably 2-9 KPa, such as 1KPa, 2KPa, 3KPa, 4KPa, 5KPa, 6KPa, 7KPa, 8KPa, 9KPa, 10KPa, preferably the range value with any value as the upper limit or the lower limit; the total reflux temperature at the top of the column is preferably 40 to 65 ℃, more preferably 45 to 60 ℃, for example 40 ℃, 45 ℃, 50 ℃, 55 ℃, 60 ℃ and 65 ℃, preferably in the range of any of the above values as the upper limit or the lower limit.
After the purity and content index of NMP at the side extraction port meet the requirements, stabilizing the temperature of the lightness-removing column, adjusting the reflux ratio to 3, extracting materials, extracting light component water and light impurities (acid, alcohol, ketone and the like generated in the reaction process) from the top of the column, and extracting NMP at the side. The present invention strictly controls the purity and the moisture index of the product by controlling the reflux ratio and the extraction temperature in the light component removal section.
And then continuously flowing the lightness-removed N-methyl pyrrolidone into an adsorption tower through a pipeline, wherein the adsorption tower is filled with a temperature-controlled adsorption material, and removing residual metal ions, particles and free amine in the N-methyl pyrrolidone through chelation of functional groups and metal ions and the like.
In the invention, the temperature-control adsorption material is a heat-sensitive polymer loaded with functional groups; the thermo-sensitive polymer is an adsorption material carrier consisting of a hydrophobic Polystyrene (PS) block and a hydrophilic poly (methoxy diglycol acrylate) (PMDEGA) block, and is an amphiphilic block copolymer synthesized by Atom Transfer Radical Polymerization (ATRP), wherein the hydrophilic block is modified by a carboxylic acid (COOH) end group and has thermal responsiveness, and a high-molecular-weight anion exchange adsorption material is formed at a neutral pH value.
Further, the thermo-responsive polymer has a structure represented by formula I:
in formula I, the ratio of n to m is preferably 1: (1 to 9), more preferably 1: (2 to 8), for example, 1:1, 1:2, 1:3, 1:4, 1:5, 1:6, 1:7, 1:8, 1:9, and preferably ranges in which any of the above values is an upper limit or a lower limit. The number average molecular weight of the thermo-sensitive polymer is preferably 16000-27000.
The R is 1 Is an alkyl substituent between C1 and C4, such as-CH 2 -、-CH 2 CH 2 -、-CH 2 CH 2 CH 2 -、-C(CH 3 ) 2 -、-CH 2 CH 2 CH 2 CH 2 -、-CH 2 CHCH 3 CH 2 -or-CH 2 C(CH 3 ) 2 -; the R is 2 Is a halogen radical, such as-Br, -Cl, -I or-F.
In the thermo-responsive polymer of the present invention, the concentration ratio of the carboxyl end group to the methoxy group is preferably 1: (1-20), more preferably 1: (5-15) such as 1:1, 1: 2. 1: 3. 1: 4. 1: 5. 1: 6. 1: 7. 1: 8. 1: 9. 1: 10. 1: 11. 1: 12. 1: 13. 1: 14. 1: 15. 1: 16. 1: 17. 1: 18. 1: 19. 1: 20. 1: 21. 1: 22. 1: 23. 1: 24. 1: 25. 1: 26. 1: 27. 1: 28. 1: 29. 1:30 is preferably a range value having any of the above numerical values as an upper limit or a lower limit.
In the invention, the heat-sensitive polymer is easily influenced by pH, so the content of alkaline substances in NMP needs to be controlled, and the content of weakly alkaline light components such as organic amine in NMP is controlled by a rectification process before ion adsorption.
In the invention, the thermo-sensitive polymer is of a porous structure and is used as an organic porous framework material to load a functional group.
In the present invention, the functional group is preferably monomethyl sulfide and/or long alkyl methyl sulfide; compared with the prior commonly used thiol unit as an adsorbed functional group, the functional group in the invention has the advantages of good stability, strong oxidation resistance and the like.
In the present invention, the molar ratio of the functional group to the methoxy group in the thermo-responsive polymer is preferably 1: (1-40), more preferably 1: (5 to 35) such as 1:1, 1:5, 1:10, 1:15, 1:20, 1:25, 1:30, 1:35, 1:40, and preferably ranges having any of the above values as the upper limit or the lower limit.
The temperature control adsorbing material can regulate the adsorption effect on ions according to the temperature, and the temperature regulation is realized through the hydrophilic block methoxy diglycol acrylate modified by the carboxylic acid end group, and the temperature control adsorbing material is mainly characterized by showing reversible thermosensitive phase change. At normal temperature, the surface groups with negative charges on the hydrophilic block can adsorb metal ions, after adsorption saturation, the environment temperature is changed, after the cloud point temperature is reached, the surface groups become hydrophobic and micro-phase separation occurs, the driving mechanism is that the groups are deprotonated to induce structural rearrangement, so that the pKa deviation is caused, the adsorption capacity of ionic impurities is changed, and the regeneration can be realized through simple water washing.
In the invention, the regeneration temperature is preferably 45-65 ℃.
In the invention, the temperature-control adsorption material is preferably prepared according to the following steps:
mixing a thermo-responsive polymer with a precursor solution of a functional group which reacts with a carboxyl group to graft the functional group to R in the presence of an initiator 2 And (4) obtaining the temperature-controlled adsorbing material.
In the invention, the initiator is preferably azobis (isobutyronitrile), and the precursor solution of the functionalized group is preferably a thioketone solution corresponding to the group. The concentration of the precursor solution of the functional group is preferably 0.5-2 mol/L, and more preferably 1-1.5 mol/L.
In the present invention, the volume ratio of the thermo-responsive polymer to the precursor solution of the functional group is preferably 1: (0.01 to 0.2), more preferably 1: (0.05 to 0.15), for example, 1:0.04, 1:0.06, 1:0.08, 1:0.1, 1:0.12, 1:0.14, preferably in the range of any of the above values as the upper or lower limit.
The temperature of the load is preferably 20-300 ℃, more preferably 50-250 ℃, such as 40 ℃, 60 ℃, 80 ℃, 100 ℃, 120 ℃ and 140 ℃, and preferably is a range value taking any value as an upper limit or a lower limit; the loading time is preferably 30-370 min, more preferably 50-300 min, such as 100min, 120min, 140min, 160min, 180min, 200min, preferably any of the above values as an upper limit or a lower limit.
In the invention, the lightness-removed NMP material is condensed to room temperature, enters from the top of the adsorption tower, is adsorbed by the temperature control adsorption material, and is extracted from the bottom of the adsorption tower to obtain the electronic grade N-methylpyrrolidone.
The purification method of the invention needs to have requirements on process equipment, and the inner wall, the pipeline and the container of the adsorption device are made of polytetrafluoroethylene materials, so that the content of metal ions is strictly controlled; the operation of the electronic grade N-methyl pyrrolidone has special requirements on the environment, and an adsorption device and material extraction are operated in a clean room.
The light component removal tower and the regeneration system of the adsorption tower are thermally coupled, so that the heat can be recycled, the steam consumption is reduced, and the energy consumption is reduced.
The invention provides a method for purifying N-methylpyrrolidone, which comprises the following steps: A) introducing industrial grade N-methyl pyrrolidone into a lightness-removing tower, and obtaining the N-methyl pyrrolidone after lightness removal under the condition of reduced pressure; B) conveying the lightness-removed N-methyl pyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-controlled adsorption material to obtain purified N-methyl pyrrolidone; the temperature control adsorption material is a heat-sensitive polymer loaded with functional groups; the thermo-responsive polymer has a structure represented by formula I: in formula I, the ratio of n to m is 1: (1-9), wherein the data molecular weight of the thermal induction polymer is 11000-61000; the functional group is a thioether group. The invention adopts a rectification coupling ion adsorption mode, adopts a light removal device to control the purity, the amine content and the moisture content of light impurities in the N-methyl pyrrolidone, and then removes metal ions in the N-methyl pyrrolidone through an adsorption system. The obtained electronic grade NMP product has purity, moisture, metal ion, organic amine and other impurities reaching the standard of high-end industry. The adsorption material adopts an intelligent polymer system based on a thermal switch, functional groups are loaded on the surface of the polymer, residual impurities including metal ions, organic anions and particles are further removed after the NMP with the purity and moisture reaching the standard is treated and rectified, the purity of the finally obtained NMP product can reach 99.99%, the moisture is less than 50ppm, the content of single metal ions is less than 0.1ppb, the content of organic amine is less than 50ppm, and the product quality is superior to that of the existing products in the market.
In order to further illustrate the present invention, the following examples are provided to describe the purification method of N-methylpyrrolidone, but should not be construed as limiting the scope of the present invention.
Example 1
This embodiment, including taking off light tower and adsorption tower, take off light tower and be filler rectifying column, adopt the stainless steel filler, the adsorbing material that the adsorption tower was filled adopts the temperature control material who has carried the functional group, takes off light tower and adsorption tower and is equipped with the condenser within a definite time. The process flow is shown in figure 2, and specifically comprises the following steps:
the technical grade NMP is used as a raw material, and is fed from the middle part of a light component removal tower I through a delivery pump E-4, the pressure at the top of the tower is 5-10 kPa, the top temperature is 45-60 ℃, and the reflux ratio is 3. Light components are extracted from the top of the tower, after organic amine of the materials is qualified, side-extracted materials enter a condenser E-5 through a pipeline to be condensed, the materials cooled to room temperature enter the absorption tower from the top of the absorption tower at the flow rate of 10ml/min, and an NMP-m sample is extracted from the bottom of the tower II after being absorbed by an absorption material. And (3) carrying out gas chromatography purity analysis on the sample, and measuring the content of the metal ions by atomic absorption spectroscopy. The results are shown in Table 1.
The preparation method of the temperature control adsorbing material loaded with the functional groups comprises the following steps:
firstly, soaking a thermo-sensitive polymer (m is 47, n is 73) with a structure shown in a formula I-1 in a 1mol/L monomethyl sulfide precursor solution, and adding methyl sulfideEther (-S-CH) 3 ) 0.6% by volume of azobis (isobutyronitrile) initiator, wherein the volume ratio of the substrate to the functionalized group precursor solution is 1:0.08, preserving the heat for 150min at the temperature of 60 ℃, and drying to obtain the temperature-controlled adsorbing material.
Example 2
The purification process of NMP in example 1 was used to purify industrial NMP and collect a sample of NMP-a. And (3) carrying out gas chromatography purity analysis on the sample, and measuring the content of the metal ions by atomic absorption spectroscopy. The results are shown in Table 1.
The adsorbing material for filling the adsorption tower in the adsorption section is prepared by the following steps:
the thermo-responsive polymer having the structure of formula I-1 used in example 1 (m-47, n-73) was first immersed in a 1mol/L long alkyl methyl sulfide precursor solution, and methyl sulfide (-S-CH) was added 3 ) 0.6% by volume of azobis (isobutyronitrile) initiator, wherein the volume ratio of the substrate to the functionalized group precursor solution is 1:0.08, preserving the heat for 150min at the temperature of 60 ℃, and drying to obtain the temperature-controlled adsorbing material.
Example 3
The purification process of NMP in example 1 was used to purify industrial NMP and collect NMP-ma sample. And (3) performing gas chromatography purity analysis on the sample, and measuring the content of the metal ions by atomic absorption spectroscopy. The results are shown in Table 1.
The adsorbing material for filling the adsorption tower in the adsorption section is prepared by the following steps:
the thermo-responsive polymer having the structure of formula I-1 used in example 1 (m-47, n-73) was first immersed in a mixed precursor solution of monomethyl sulfide and long alkyl methyl sulfide at a molar ratio of 1:1, and methyl sulfide (-S-CH) was added 3 ) 0.6% by volume of azobis (isobutyronitrile) initiator, wherein the volume ratio of the substrate to the functionalized group precursor solution is 1:0.08, preserving the heat for 150min at the temperature of 60 ℃, and drying to obtain the temperature-controlled adsorbing material.
Comparative example 1
The purification process of NMP in example 1 was used to purify industrial NMP and collect NMP-1 sample. And (3) carrying out gas chromatography purity analysis on the sample, and measuring the content of the metal ions by atomic absorption spectroscopy. The results are shown in Table 1.
The thermo-responsive polymer having the structure of formula I-1 used in example 1 (m-47, n-73) was used as it is without loading the functional group on the adsorbent packed in the adsorption column of the adsorption section.
Comparative example 2
The purification process of NMP in example 1 was used to purify industrial NMP and collect NMP-2 sample. And (3) carrying out gas chromatography purity analysis on the sample, and measuring the content of the metal ions by atomic absorption spectroscopy. The results are shown in Table 1.
The adsorbing material for filling the adsorption tower in the adsorption section is prepared by the following steps:
the thermo-responsive polymer having the structure of formula I-1 used in example 1 (m 47, n 73) was first soaked in a methyl mercaptan precursor solution, 0.6% azobis (isobutyronitrile) binder, calculated as methyl mercaptan, was added, wherein the volume ratio of the substrate to the functionalized group precursor solution was 1:0.08, preserving the heat for 150min at the temperature of 60 ℃, and drying to obtain the temperature-controlled adsorbing material.
TABLE 1 quality test results of N-methylpyrrolidone in examples of the present invention
| Sample (I) | Purity (%) | Total amines (ppm) | Total amount of Metal ions (ppb) |
| NMP feedstock | 99.5 | 65 | ＞1000 |
| NMP-m | 99.91 | 4 | ＜10 |
| NMP-a | 99.95 | 5 | ＜10 |
| NMP-ma | 99.94 | 4 | ＜10 |
| NMP-1 | 99.89 | 32 | 536 |
| NMP-2 | 99.91 | 16 | 310 |
The foregoing is only a preferred embodiment of the present invention, and it should be noted that, for those skilled in the art, various modifications and decorations can be made without departing from the principle of the present invention, and these modifications and decorations should also be regarded as the protection scope of the present invention.
Claims (6)
1. A method for purifying N-methyl pyrrolidone comprises the following steps:
A) introducing industrial grade N-methylpyrrolidone into a lightness-removing tower, and carrying out total reflux under the reduced pressure condition to obtain lightness-removed N-methylpyrrolidone;
B) conveying the lightness-removed N-methyl pyrrolidone to an adsorption tower, and adsorbing metal ions by using a temperature-controlled adsorption material to obtain purified N-methyl pyrrolidone;
the temperature control adsorption material is a heat-sensitive polymer loaded with functional groups; the thermo-responsive polymer has a structure represented by formula I:
in formula I, m =47, n =73, R 1 Is an alkyl group of between C1 and C4, R 2 The thermal induction polymer is a halogen group, and the number average molecular weight of the thermal induction polymer is 11000-61000;
the functional group is monomethyl sulfide and/or long alkyl methyl sulfide;
the temperature control adsorbing material is prepared according to the following steps: soaking a thermo-responsive polymer with a structure shown in a formula I, wherein m =47 and n =73 is soaked in 1mol/L of a monomethyl sulfide and/or long alkyl methyl sulfide precursor solution, and adding 0.6% of azo bis (isobutyronitrile) initiator calculated by methyl sulfide, wherein the volume ratio of the thermo-responsive polymer to the functionalized group precursor solution is 1:0.08, preserving the heat for 150min at the temperature of 60 ℃, and drying to obtain the temperature-controlled adsorbing material.
2. The purification method of claim 1, wherein the purity of the N-methyl pyrrolidone fully refluxed to the column side line of the light component removal column at the column top temperature of 45-60 ℃ and the operation pressure of 1-10 KPa is more than 99.9%, the water content is less than 20ppm, and the organic amine is less than 20 ppm;
after the temperature is stable, the reflux ratio is adjusted to 3, and the lightness-removed N-methyl pyrrolidone is extracted.
3. The purification method according to claim 1, wherein the thermo-responsive polymer has a molar ratio of carboxyl end groups to methoxy groups of 1: (1-20).
4. The purification method according to claim 1, wherein the molar ratio of the functionalized group to the methoxy group is 1: (1-40).
5. The purification method according to claim 1, wherein the temperature-controlled adsorption material adsorbs metal ions at normal temperature, and after adsorption saturation, the temperature-controlled adsorption material is washed with water at 45 to 65 ℃ to regenerate the temperature-controlled adsorption material.
6. The purification method of claim 1, wherein the adsorption tower is provided with a temperature-controlled adsorbent material regeneration system, and the light component removal tower is thermally coupled to the temperature-controlled adsorbent material regeneration system.
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| CN102190611A (en) * | 2011-04-01 | 2011-09-21 | 四川天华股份有限公司 | Method for purifying N-methyl pyrrolidone and gamma-butyrolactone |
| CN108299266A (en) * | 2018-01-30 | 2018-07-20 | 宁波大学 | The preparation method of high purity N-methyl pyrrolidone |
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| CN102399179B (en) * | 2010-09-17 | 2014-06-18 | 上海化学试剂研究所 | Production process for ultra-pure N-methylpyrrolidone |
| CN109232352B (en) * | 2018-09-19 | 2024-03-19 | 江阴市大洋固废处置利用有限公司 | N-methyl pyrrolidone decompression purification system and purification method |
| CN113429329A (en) * | 2021-07-06 | 2021-09-24 | 镇江润晶高纯化工科技股份有限公司 | Purification method of semiconductor grade N-methyl pyrrolidone |
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| CN102190611A (en) * | 2011-04-01 | 2011-09-21 | 四川天华股份有限公司 | Method for purifying N-methyl pyrrolidone and gamma-butyrolactone |
| CN108299266A (en) * | 2018-01-30 | 2018-07-20 | 宁波大学 | The preparation method of high purity N-methyl pyrrolidone |
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