CN112552202B

CN112552202B - Method for preparing electronic grade N-methyl formamide under low temperature condition

Info

Publication number: CN112552202B
Application number: CN202011442274.8A
Authority: CN
Inventors: 雷爱文; 张恒; 崔德文; 万建龙
Original assignee: Suqian Xinya Technology Co ltd; Wuhan University WHU
Current assignee: Suqian Xinya Technology Co ltd; Wuhan University WHU
Priority date: 2020-12-08
Filing date: 2020-12-08
Publication date: 2022-02-15
Anticipated expiration: 2040-12-08
Also published as: CN112552202A

Abstract

The invention provides a method for preparing electronic grade N-methylformamide under the saturated low-temperature condition, which is characterized by comprising the following steps: under the conditions of normal pressure and low temperature, liquid methyl formate reacts with liquid methylamine with equal mass to obtain the product N-methylformamide. The whole reaction process is carried out under the low temperature condition, a high-temperature high-pressure reaction device is not needed, impurities introduced due to corrosion can be reduced as far as possible, and the possibility of introducing the impurities by the reaction device is reduced to the maximum extent, so that the electronic grade N-methylformamide with extremely high purity can be obtained.

Description

Method for preparing electronic grade N-methyl formamide under low temperature condition

Technical Field

The invention belongs to the field of synthetic chemistry, and particularly relates to a method for preparing electronic-grade N-methylformamide under a low-temperature condition.

Background

N-methylformamide is an important chemical raw material, can be used for synthesis of medicines, pesticides, artificial leather and the like, and is widely used as a solvent. Particularly, with the development of the electronics industry, N-methylformamide has been widely used as a cleaning agent in recent years, and there is an increasing demand for the N-methylformamide, which is an ultra-pure electronic semiconductor grade.

Although the preparation method of N-methylformamide has been reported, for example, the N-methylformamide can be prepared by reacting methyl formate with methylamine, the preparation of ultra-pure N-methylformamide of an electronic semiconductor grade faces huge challenges, and the core problem is to reduce the content of metal ions in the N-methylformamide. Since the atmospheric boiling point of methyl formate is 32 ℃, the atmospheric pressure of methylamine is a gas, and the reaction of methyl formate with methylamine is an exothermic reaction, the preparation of N-methylformamide by reacting methyl formate with methylamine requires a problem of pressure resistance, and the reaction is generally carried out under heating in a pressure-resistant vessel. The pressure-resistant container increases the safety problem and the production cost in the production process, and the heating condition increases the corrosion to equipment in the reaction process, so that the content of metal ions in the product is extremely easy to exceed the standard.

Disclosure of Invention

The present invention has been made to solve the above problems, and an object of the present invention is to provide a method for producing an electronic grade N-methylformamide at a low temperature, in which a reaction process is performed at a low temperature, heating is not required, a reaction vessel is not required to be resistant to pressure, and an electronic grade N-methylformamide having an extremely high purity can be obtained.

In order to achieve the purpose, the invention adopts the following scheme:

the invention provides a method for preparing electronic grade N-methylformamide under low temperature, which is characterized by comprising the following steps: under the conditions of normal pressure and low temperature, liquid methyl formate reacts with liquid methylamine with equal mass to obtain the N-methylformamide.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition, provided by the invention, specifically comprises the following steps:

step 1, reacting liquid methyl formate with liquid methylamine with equal mass under the conditions of normal pressure and low temperature to obtain reaction products of N-methylformamide and methanol;

and 2, distilling the reaction product to remove the methanol, wherein the residual product is the N-methylformamide.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: in step 1, the low temperature is below-6.3 ℃.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: in step 1, the low temperature is below-10 ℃.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: in step 1, the low temperature is-10 ℃ to-70 ℃.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: in step 1, the low temperature is-30 ℃.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: in step 1, the reaction device is a glass or plastic container.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: the product N-methylformamide has no metal ion detected at ppb level.

Further, the method for preparing the electronic grade N-methylformamide under the low-temperature condition provided by the invention can also have the following characteristics: no solvent is needed in the reaction process.

Action and Effect of the invention

1) The invention does not need a high-temperature high-pressure reaction device, can adopt materials such as glass or plastics to manufacture the reaction device, reduces the cost of the reaction device, simultaneously reduces the possibility of introducing impurities into the reaction device to the maximum extent, and can prepare the electronic grade N-methylformamide.

2) The method can efficiently synthesize the N-methylformamide under the low-temperature condition, and can reduce impurities introduced by corrosion as much as possible under the low-temperature condition.

3) The reaction designed by the invention is carried out under normal pressure and low temperature, the reaction condition is easy to control, and the potential safety hazard is very small.

4) On the premise of ensuring that the methylamine is in a liquid state at normal pressure, the method can meet the corresponding production requirement by adjusting the low-temperature of the reaction and the flow rate of the methylamine.

5) The method does not need a solvent, directly carries out liquid-liquid reaction on the methyl formate and the methylamine under normal pressure and low temperature, has simple preparation method, extremely high reaction speed and no high-temperature and high-pressure requirements on a reaction device, and the product only contains methanol except N-methylformamide, is very easy to separate and is very suitable for large-scale industrial use.

Drawings

FIG. 1 is a three-dimensional on-line infrared spectrum of the reaction of methyl formate with methylamine as contemplated in an example of the present invention;

FIG. 2 is a graph of the concentration of methyl formate and N-methylformamide as a function of time during the reaction involved in the example of the invention.

Detailed Description

The following provides a detailed description of a specific embodiment of the method for preparing electronic grade N-methylformamide under low temperature conditions according to the present invention with reference to the accompanying drawings.

< example >

Adding 30mL of methyl formate into a 100mL glass beaker, adding stirring magnetons, putting the glass beaker into a cold trap, cooling the glass beaker to the temperature of minus 30 ℃, then introducing 12L of methylamine gas (normal temperature and normal pressure) into the cold trap, immediately liquefying the methylamine gas at low temperature to obtain methylamine liquid, and mixing the methylamine liquid with the methyl formate in a liquid phase to quickly react to generate N-methylformyl and methanol; then distilling to remove the methanol to obtain the pure N-methylformamide.

As shown in figures 1 and 2, the reaction of methyl formate and methylamine is monitored by an online infrared spectrometer at the temperature of-30 ℃, and the result shows that the methyl formate and the methylamine are mixed to react, which indicates that the reaction of the methyl formate and the methylamine is very quick at the temperature of-30 ℃, and the reaction is not influenced at low temperature.

In addition, at low temperature, methyl formate and methylamine are both in liquid state at normal pressure, the reaction does not need to be carried out under heating and high pressure, the impurity content of Al and Fe in the reaction product N-methylformamide is detected by ICP-MS, the Al and Fe are not detected at ppb level, and the purity reaches the electronic level, which indicates that the method is favorable for preparing the ultra-high purity N-methylformamide.

The above embodiments are merely illustrative of the technical solutions of the present invention. The method for preparing electronic grade N-methylformamide under the low temperature condition is not limited in the content described in the above embodiment, but is subject to the scope defined by the claims. Any modification or supplement or equivalent replacement made by a person skilled in the art on the basis of this embodiment is within the scope of the invention as claimed in the claims.

Claims

1. A method for preparing electronic grade N-methylformamide under low temperature condition is characterized in that:

under the conditions of normal pressure and low temperature, liquid methyl formate reacts with liquid methylamine with equal mass to obtain N-methylformamide,

wherein the low temperature is below-6.3 ℃.

2. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein the low temperature is below-10 ℃.

3. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein the low temperature is-10 ℃ to-70 ℃.

4. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein the low temperature is-30 ℃.

5. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein the reaction device is a glass or plastic container.

6. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein the product N-methylformamide has no metal ion detected at ppb level.

7. The method of claim 1 for preparing electronic grade N-methylformamide at cryogenic conditions, wherein:

wherein, no solvent is needed in the reaction process.

8. The method for preparing electronic grade N-methylformamide under the low-temperature condition according to claim 1, further comprising:

and distilling the reaction product to remove methanol, wherein the residual product is N-methylformamide.