阅读说明：本技术 一种高纯度n-甲基吡咯烷酮中杂质去除工艺 (Process for removing impurities in high-purity N-methyl pyrrolidone ) 是由 廖中华 于 2021-06-30 设计创作，主要内容包括：本发明公开一种高纯度N-甲基吡咯烷酮中杂质去除工艺,包括以下步骤：将N-甲基吡咯烷酮以30-100ml/min的流速在预热器预热,通过分子筛选装置以压力40-500Pa进行渗透蒸发,经过分子筛选装置的筛膜循环管道后,收集去除甲胺和水分的N-甲级吡咯烷酮；经过多次的循环过滤之后,从而得到高纯度的N-甲级吡咯烷酮；本发明方法操作简便,能耗低,效果好,具有广泛的工业化生产前景。(The invention discloses a process for removing impurities in high-purity N-methyl pyrrolidone, which comprises the following steps: preheating N-methyl pyrrolidone in a preheater at the flow rate of 30-100ml/min, carrying out pervaporation through a molecular screening device at the pressure of 40-500Pa, and collecting N-methyl pyrrolidone with methylamine and moisture removed after passing through a screen membrane circulating pipeline of the molecular screening device; after multiple times of circulating filtration, high-purity N-methyl pyrrolidone is obtained; the method has the advantages of simple and convenient operation, low energy consumption, good effect and wide industrial production prospect.)

1. A process for removing impurities in high-purity N-methyl pyrrolidone is characterized by comprising the following steps: the method comprises the following steps:

preheating N-methylpyrrolidone in a preheater (2) at the flow rate of 30-100ml/min, carrying out pervaporation through a molecular screening device (3) at the pressure of 40-500Pa, and collecting N-methyl pyrrolidone with methylamine and moisture removed after passing through a sieve membrane circulating pipeline of the molecular screening device (3); after multiple times of circulating filtration, the high-purity N-methyl pyrrolidone is obtained.

2. The process according to claim 1 for removing impurities from high purity N-methylpyrrolidone, wherein: the preheating temperature of the N-methyl pyrrolidone is 85-130 ℃, and the temperature of the N-methyl pyrrolidone in the molecular screening device (3) is kept above 85 ℃.

3. The process according to claim 1 for removing impurities from high purity N-methylpyrrolidone, wherein: the sieve membrane circulating pipeline is spirally arranged in the molecular screening device (3), and the sieve membrane holes of the sieve membrane circulating pipeline can only pass methylamine molecules and water molecules.

4. The process according to claim 1 for removing impurities from high purity N-methylpyrrolidone, wherein: the discharge hole of the molecular screening device (3) is connected to the raw material tank (1) through a membrane pump (4); and is communicated with the discharge tank (5) through a valve (6).

5. The process according to claim 1 for removing impurities from high purity N-methylpyrrolidone, wherein: the waste port of the molecular screening device (3) is connected to a waste tank (7) through a valve (6).

Technical Field

The invention relates to the technical field of N-methyl pyrrolidone production, in particular to a process for removing impurities in high-purity N-methyl pyrrolidone.

Background

N-methylpyrrolidone (NMP) belongs to nitrogen heterocyclic compound, and is mainly applied to petrochemical industry, plastic industry, medicine, pesticide, dye, lithium ion battery manufacturing industry and other industries. In the microelectronic industry and the semiconductor industry, N-methyl pyrrolidone can be used for cleaning agents of precision instruments or circuit boards, photoresist removing liquid, solvents for LCD liquid crystal material production, electrode auxiliary materials of lithium batteries and the like. Due to the rapid development of the IT industry, especially along with the development of miniaturization and high-speed processing of integrated circuits, the requirements for methylamine and moisture in the sesmic 8 standard of N-methylpyrrolidone are strict, namely, the content of methylamine is less than 5ppm, and the content of moisture is less than 0.03%.

In the prior art, the N-methyl pyrrolidone is prepared by aminolysis of gamma-butyrolactone serving as a raw material and methylamine, and inevitable impurities such as methylamine, moisture and the like exist. In the existing N-methyl pyrrolidone purification technology, the method for removing methylamine and moisture mainly adopts continuous distillation or micro-boiling distillation; however, the method has high investment cost and complex process operation, and is difficult to popularize and apply.

Disclosure of Invention

The invention aims to provide an impurity removal process to overcome the defects of the prior art.

In order to achieve the purpose, the invention provides the following technical scheme:

a process for removing impurities in high-purity N-methyl pyrrolidone comprises the following steps:

preheating N-methyl pyrrolidone in a preheater at the flow rate of 30-100ml/min, carrying out pervaporation through a molecular screening device at the pressure of 40-500Pa, and collecting N-methyl pyrrolidone with methylamine and moisture removed after passing through a screen membrane circulating pipeline of the molecular screening device; after multiple times of circulating filtration, the high-purity N-methyl pyrrolidone is obtained.

Preferably, the preheating temperature of the N-methyl pyrrolidone is 85-130 ℃, and the temperature of the N-methyl pyrrolidone in the molecular sieving device is kept above 85 ℃.

Preferably, the sieve membrane circulation pipeline is spirally arranged in the molecular screening device, and the sieve membrane holes of the sieve membrane circulation pipeline can only pass methylamine molecules and water molecules.

Preferably, the discharge port of the molecular screening device is connected to the raw material tank through a membrane pump; and is communicated with the discharge tank through a valve.

Preferably, the waste port of the molecular sieving apparatus is connected to the canister by a valve.

Compared with the prior art, the invention has the beneficial effects that:

in the method, N-methyl pyrrolidone is subjected to pervaporation, methylamine and moisture in the N-methyl pyrrolidone can be effectively removed through one-step simple cyclic operation, the purity of the obtained N-methyl pyrrolidone is more than or equal to 99.8 percent, the content of methylamine is lower than 5ppm, the moisture content is less than 0.03 percent, and the obtained N-methyl pyrrolidone completely meets the SEMIC8 standard; the method has the advantages of simple operation, low energy consumption, good effect and wide industrial production prospect.

Drawings

In order to more clearly illustrate the technical solutions of the embodiments of the present invention, the drawings used in the description of the embodiments will be briefly introduced below, and it is obvious that the drawings in the following description are only some embodiments of the present invention, and it is obvious for those skilled in the art that other drawings can be obtained according to the drawings without creative efforts.

FIG. 1 is a schematic view of the preparation process of the present invention.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the drawings in the embodiments of the present invention, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all of the embodiments. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present invention.

Referring to fig. 1, the present invention provides a technical solution:

a process for removing impurities in high-purity N-methyl pyrrolidone comprises the following steps:

preheating N-methyl pyrrolidone in a preheater 2 at the flow rate of 30-100ml/min, carrying out pervaporation through a molecular screening device 3 at the pressure of 40-500Pa, and collecting N-methyl pyrrolidone with methylamine and moisture removed after passing through a sieve membrane circulating pipeline of the molecular screening device 3; after multiple times of circulating filtration, the high-purity N-methyl pyrrolidone is obtained.

Preferably, the preheating temperature of the N-methylpyrrolidone is 85-130 ℃, and the temperature of the N-methylpyrrolidone in the molecular sieving device 3 is kept above 85 ℃.

Preferably, the sieve membrane circulation pipeline is spirally arranged in the molecular sieving device 3, and the sieve membrane holes of the sieve membrane circulation pipeline can only pass methylamine molecules and water molecules.

Preferably, the discharge port of the molecular sieving device 3 is connected to the raw material tank 1 through a membrane pump 4; and communicates with the discharge tank 5 through a valve 6.

Preferably, the waste port of the molecular sieving apparatus 3 is connected to a waste tank 7 through a valve 6.

In the embodiment:

5000ml of industrial grade N-methyl pyrrolidone is placed in a raw material tank 1, preheated to 90 ℃ through a preheater 2 at the flow rate of 50ml/min, then subjected to pervaporation through a molecular screening device 3, the pressure of the molecular screening device 3 is controlled to be 500Pa, feed liquid passes through a screen membrane circulating pipeline, returns to the raw material tank 1 through a membrane pump 4, and is screened for methylamine molecules and water molecules through the screen membrane pores of the screen membrane circulating pipeline. After 120min, sampling and analyzing from a valve 6, wherein the content of methylamine in the feed liquid is 3.5ppm, the content of water is 0.006 percent, and the detection result meets the SEMIC8 standard; the separated methylamine molecules and water molecules are collected in a waste tank 7 through a valve 6.

In the method, N-methyl pyrrolidone is subjected to pervaporation, methylamine and moisture in the N-methyl pyrrolidone can be effectively removed through one-step simple cyclic operation, the purity of the obtained N-methyl pyrrolidone is more than or equal to 99.8 percent, the content of methylamine is lower than 5ppm, the moisture content is less than 0.03 percent, and the obtained N-methyl pyrrolidone completely meets the SEMIC8 standard; the method has the advantages of simple operation, low energy consumption, good effect and wide industrial production prospect.

In the description herein, references to the description of "one embodiment," "an example," "a specific example" or the like are intended to mean that a particular feature, structure, material, or characteristic described in connection with the embodiment or example is included in at least one embodiment or example of the invention. In this specification, the schematic representations of the terms used above do not necessarily refer to the same embodiment or example. Furthermore, the particular features, structures, materials, or characteristics described may be combined in any suitable manner in any one or more embodiments or examples.

The preferred embodiments of the invention disclosed above are intended to be illustrative only. The preferred embodiments are not intended to be exhaustive or to limit the invention to the precise embodiments disclosed. Obviously, many modifications and variations are possible in light of the above teaching. The embodiments were chosen and described in order to best explain the principles of the invention and the practical application, to thereby enable others skilled in the art to best utilize the invention. The invention is limited only by the claims and their full scope and equivalents.