Equipment for reducing total amine content in NMP (N-Methyl Pyrrolidone) rectification

Abstract

The utility model relates to the technical field of organic matter purification, in particular to equipment for reducing total amine content in NMP (N-Methyl Pyrrolidone) rectification, which is sequentially connected with an azeotropic tower, a distillation tower, a gas stripping tower, a mixing tower, an adsorption tower, a rectifying tower and a finished product tower through pipelines according to the purification direction of NMP, the volume ratio of the azeotropic solvent in the azeotropic tower to the N-methyl pyrrolidone is (15-25): 1, the azeotropic solvent is toluene or benzene or ethanol or isopropanol, and the gas introduced into the gas stripping tower is air or carbon dioxide or nitrogen; and the adsorption tower is filled with a thioether functionalized porphyrin structure porous organic polymer. According to the device disclosed by the utility model, recovered N-methyl pyrrolidone and industrial-grade N-methyl pyrrolidone can be respectively purified, metal ions in the N-methyl pyrrolidone are adsorbed by the thioether functionalized porphyrin structure porous organic polymer, and then the electronic-grade N-methyl pyrrolidone is obtained by vacuum distillation, so that the device is convenient and efficient to use and good in practicability.

Description

Technical Field

[0001] The utility model relates to the technical field of organic matter purification, in particular to a device for reducing the total amine content in NMP distillation. Background Art

[0002] N-methylpyrrolidone (NMP for short) is a colorless, highly polar, chemically stable and thermally stable liquid. At the same time, it has the characteristics of low vapor pressure and good solubility, and can be used as an organic solvent and extractant. At present, N-methylpyrrolidone can be divided into ordinary grade, industrial grade and electronic grade according to different product indicators. Among them, electronic grade N-methylpyrrolidone is widely used in high-end industries such as semiconductors and lithium batteries, and can be used as a semiconductor circuit board cleaning agent and lithium battery electrolyte solvent. N-methylpyrrolidone used in high-end industries has strict index requirements for purity, moisture, metal ions, organic amines, etc. For example, in the lithium-ion battery industry, the moisture in N-methylpyrrolidone will react with the solvent in the electrolyte and thus affect the activity or life of the lithium battery. The metal impurity ions with a lower reduction potential than lithium ions will greatly reduce the reversible capacity of the lithium battery. At present, domestic electronic-grade products mainly rely on imports, and there are technical barriers in the purification process of electronic-grade NMP. Most domestic purification processes cannot meet the needs of high-end industries.

[0003] There are two types of N-methylpyrrolidone on the market: synthetic and recycled. Industrially synthesized N-methylpyrrolidone uses γ-butyrolactone and methylamine as raw materials. The resulting product is purified by decompression, dehydration, and distillation. N-methylpyrrolidone contains some organic ammonia, water, and impurity particles; recycled N-methylpyrrolidone contains a large proportion of water, metal ions, and organic impurities.

[0004] In the prior art, most of the purification devices for N-methylpyrrolidone use distillation to remove excess water and metal ions in NMP through continuous distillation, and the recovered NMP is difficult to remove through a single distillation; at the same time, trace metals have sublimation volatility, and trace heavy metals in N-methylpyrrolidone will volatilize as the material evaporates during distillation and cannot be removed well, so the purity and metal ions of the purified NMP cannot meet the requirements of electronic grade products. Summary of the invention

[0005] The technical problem to be solved by the utility model is to provide a device for reducing the total amine content in NMP distillation to solve the above problem.

[0006] The utility model solves the above technical problem through a technical solution: a device for reducing the total amine content in NMP distillation, wherein an azeotropic tower, a distillation tower, a gas stripping tower, a mixing tower, an adsorption tower, a distillation tower and a finished product tower are sequentially connected through pipelines according to the purification direction of N-methylpyrrolidone, and a light removal tower is connected to the left side of the mixing tower.

[0007] As a preferred technical solution of the utility model, the volume ratio of the azeotropic solvent in the azeotropic tower to the volume ratio of N-methylpyrrolidone is (15-25):1.

[0008] As a preferred technical solution of the utility model, the azeotropic solvent is toluene or benzene or ethanol or isopropanol.

[0009] As a preferred technical solution of the utility model, the gas introduced into the stripping tower is air, carbon dioxide or nitrogen; the temperature of the gas is 100-180°C.

[0010] As a preferred technical solution of the utility model, the adsorption tower is filled with a porous organic polymer with a thioether functionalized porphyrin structure.

[0011] As a preferred technical solution of the utility model, the volume ratio of the thioether functionalized porphyrin structure porous organic polymer to N-methylpyrrolidone is 1: (4-8).

[0012] As a preferred technical solution of the utility model, the vacuum degree in the distillation tower is 300-800Pa, the distillation bottom temperature is 80-160°C, the liquid temperature in the kettle is 80-160°C, the kettle top temperature is 50-140°C, and the reflux ratio is controlled to be (4-9):1.

[0013] As a preferred technical solution of the utility model, the top temperature of the lightness removal tower is 48-56°C and the pressure is 5-8KPa.

[0014] Since the utility model adopts such a structure, the equipment can purify the recovered N-methylpyrrolidone and the industrial-grade N-methylpyrrolidone respectively, adsorb the metal ions in the N-methylpyrrolidone through the porous organic polymer with thioether functionalized porphyrin structure, and then obtain the electronic-grade N-methylpyrrolidone through vacuum distillation. The equipment is convenient, efficient and practical. BRIEF DESCRIPTION OF THE DRAWINGS

[0015] Figure 1 The utility model discloses a process flow chart of a device for reducing the total amine content in NMP distillation.

[0016] In the figure: 1 is an azeotropic tower, 2 is a distillation tower, 3 is a stripping tower, 4 is a mixing tower, 5 is an adsorption tower, 6 is a rectification tower, 7 is a finished product tower, and 8 is a light removal tower. DETAILED DESCRIPTION

[0017] The utility model is further described in detail below with reference to the accompanying drawings and specific embodiments.

[0018] like Figure 1As shown, the utility model is a device for reducing the total amine content in NMP distillation, which is characterized in that: an azeotropic tower 1, a distillation tower 2, a stripping tower 3, a mixing tower 4, an adsorption tower 5, a distillation tower 6 and a finished product tower 7 are connected in sequence through pipelines according to the purification direction of N-methylpyrrolidone, and a light removal tower 8 is connected to the left side of the mixing tower 4. The recovered N-methylpyrrolidone can be purified by the azeotropic tower 1, the distillation tower 2, and the stripping tower 3, and the industrial-grade N-methylpyrrolidone can be purified by the light removal tower. The metal ions in the N-methylpyrrolidone are adsorbed by the thioether-functionalized porphyrin structure porous organic polymer in the adsorption tower, and then the electronic-grade N-methylpyrrolidone is obtained by vacuum distillation. It is convenient and efficient to use and has good practicality.

[0019] The utility model further has a volume ratio of the azeotropic solvent in the azeotropic tower 1 to the volume ratio of N-methylpyrrolidone of (15-25):1, and the azeotropic solvent is toluene or benzene or ethanol or isopropanol. A large amount of azeotropic solvent (i.e. toluene or benzene or ethanol or isopropanol) can quickly form an azeotrope with the recovered N-methylpyrrolidone, saving time.

[0020] In the present invention, the gas introduced into the stripping tower 3 is air, carbon dioxide or nitrogen; and the temperature of the gas is 100-180°C.

[0021] In the utility model, the adsorption tower 5 is filled with a porous organic polymer with a thioether functionalized porphyrin structure. The porous organic polymer with a thioether functionalized porphyrin structure has a large specific surface area, good physical and chemical stability, a unique pore structure and is easy to functionalize.

[0022] The utility model further has a volume ratio of the thioether functionalized porphyrin structure porous organic polymer to N-methyl pyrrolidone of 1: (4-8). A large amount of the thioether functionalized porphyrin structure porous organic polymer can quickly adsorb metal ions in N-methyl pyrrolidone.

[0023] The utility model further has a vacuum degree in the distillation tower 6 of 300-800Pa, a distillation kettle bottom temperature of 80-160°C, a kettle liquid temperature of 80-160°C, a kettle top temperature of 50-140°C, and a controlled reflux ratio of (4-9):1.

[0024] In the present invention, the top temperature of the lightness removal tower 8 is 48-56° C., and the pressure is 5-8 KPa.

[0025] The description and application of the utility model here are illustrative and are not intended to limit the scope of the utility model to the above-described embodiments. Variations and changes of the embodiments disclosed here are possible, and the actual replacement of the embodiments and the various components equivalent to those of ordinary skill in the art are well known. It should be clear to those skilled in the art that the utility model can be implemented in other forms, structures, arrangements, proportions, and with other elements, materials, and components without departing from the spirit or essential features of the utility model. Other variations and changes can be made to the embodiments disclosed here without departing from the spirit or essential features of the utility model.

Claims

1. A device for reducing the total amine content in NMP distillation, characterized in that: According to the direction of N-methylpyrrolidone purification, an azeotropic tower (1), a distillation tower (2), a stripping tower (3), a mixing tower (4), an adsorption tower (5), a rectification tower (6) and a finished product tower (7) are connected in sequence through pipelines, and a light removal tower (8) is connected to the left side of the mixing tower (4).

2. A device for reducing the total amine content in NMP distillation according to claim 1, characterized in that: The volume ratio of the azeotropic solvent in the azeotropic column (1) to the volume ratio of N-methylpyrrolidone is (15-25):

1.

3. A device for reducing the total amine content in NMP distillation according to claim 2, characterized in that: The azeotropic solvent is toluene, benzene, ethanol or isopropanol.

4. A device for reducing the total amine content in NMP distillation according to claim 1, characterized in that: The gas introduced into the stripping tower (3) is air, carbon dioxide or nitrogen; the temperature of the gas is 100-180°C.

5. A device for reducing the total amine content in NMP distillation according to claim 1, characterized in that: The adsorption tower (5) is filled with a porous organic polymer having a thioether functionalized porphyrin structure.

6. A device for reducing the total amine content in NMP distillation according to claim 5, characterized in that: The volume ratio of the thioether functionalized porphyrin structure porous organic polymer to N-methylpyrrolidone is 1:(4-8).

7. The device for reducing the total amine content in NMP distillation according to claim 1, characterized in that: The vacuum degree in the distillation tower (6) is 300-800 Pa, the distillation bottom temperature is 80-160°C, the liquid temperature in the distillation tank is 80-160°C, the top temperature of the tank is 50-140°C, and the reflux ratio is controlled to be (4-9):

1.

8. The device for reducing the total amine content in NMP distillation according to claim 1, characterized in that: The top temperature of the lightness removal tower (8) is 48-56°C and the pressure is 5-8KPa.

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