阅读说明：本技术 一种氟甲酸三氟甲酯的制备方法及其制备装置 (Preparation method and preparation device of trifluoromethyl fluoformate ) 是由 陈立义 汪仲权 杨旭仓 郭澎湃 于 2019-11-08 设计创作，主要内容包括：本发明属于氟化工技术领域,具体涉及一种氟甲酸三氟甲酯的制备方法及其制备装置。所述氟甲酸三氟甲酯的制备方法,包括：以含氟试剂为溶剂,以六氟丙烯和氧气为反应原料,在紫外光引发下反应生成氟甲酸三氟甲酯。本发明还提供实现所述制备方法的制备装置,包括：反应釜；与所述反应釜连接的回流冷凝器；与所述回流冷凝器连接的冷阱；所述冷阱内置产品收集设备。本发明采用六氟丙烯和氧气为原料,在紫外光引发下一步法合成氟甲酸三氟甲酯,反应更加简单；而且本发明通过选择含氟试剂作为溶剂能够降低单体损耗,加快反应进程,提高转化率。(The invention belongs to the technical field of fluorine chemical industry, and particularly relates to a preparation method and a preparation device of trifluoromethyl fluoformate. The preparation method of the trifluoromethyl fluoroformate comprises the following steps: the fluorine-containing reagent is used as a solvent, hexafluoropropylene and oxygen are used as reaction raw materials, and the reaction is initiated by ultraviolet light to generate the trifluoromethyl fluoroformate. The invention also provides a preparation device for realizing the preparation method, which comprises the following steps: a reaction kettle; a reflux condenser connected with the reaction kettle; a cold trap connected to the reflux condenser; and a product collecting device is arranged in the cold trap. According to the invention, hexafluoropropylene and oxygen are used as raw materials, and the trifluoromethyl fluoroformate is synthesized by a one-step method under ultraviolet light initiation, so that the reaction is simpler; in addition, the invention can reduce monomer loss, accelerate reaction process and improve conversion rate by selecting fluorine-containing reagent as solvent.)

1. A method for preparing trifluoromethyl fluoroformate is characterized by comprising the following steps: the fluorine-containing reagent is used as a solvent, hexafluoropropylene and oxygen are used as reaction raw materials, and the reaction is initiated by ultraviolet light to generate the trifluoromethyl fluoroformate.

2. The preparation method according to claim 1, wherein the fluorine-containing reagent is selected from one or more of fluorine-containing hydrocarbon compounds, fluorine-chlorine hydrocarbon compounds or perfluoro-ether compounds; preferably one or more of perfluoropropane, trifluorotrichloroethane or perfluorodimethyl ether.

3. The method of claim 1 or 2, wherein the fluorine-containing reagent is pre-cooled to a temperature of-35 ℃ to-25 ℃ before use.

4. The production process according to any one of claims 1 to 3, wherein the hexafluoropropylene is passed at a rate of 1.0 to 8.0L/h, preferably 2 to 5L/h;

and/or the introduction speed of the oxygen is 2-10L/h, preferably 3-6L/h.

5. The process according to claim 4, wherein the ratio of the feed rate of the hexafluoropropylene to the feed rate of the oxygen is (0.8-1.5) to 1, preferably (0.9-1.2): 1.

6. the method according to any one of claims 1 to 5, wherein the ultraviolet light has a light source wavelength in the range of 100nm to 400nm, preferably 180nm to 300 nm.

7. The production method according to any one of claims 1 to 6, wherein the reaction is carried out under a low temperature condition; preferably below-25 deg.C, more preferably below-35 deg.C, and even more preferably below-55 deg.C.

8. The production method according to any one of claims 1 to 7, wherein the hexafluoropropene which is incompletely reacted is subjected to reflux condensation; preferably, the temperature of the reflux condensation is controlled between-40 ℃ and-20 ℃, and further preferably between-30 ℃ and-25 ℃.

9. The production method according to any one of claims 1 to 8, characterized in that trifluoromethyl fluoroformate obtained by the production method is subjected to low-temperature liquefaction; preferably, the temperature of the low-temperature liquefaction is controlled to be-100 to 30 ℃, and further preferably-60 to-40 ℃.

10. A production apparatus for carrying out the production method according to any one of claims 1 to 9, comprising: a reaction kettle; a reflux condenser connected with the reaction kettle; a cold trap connected to the reflux condenser; and a product collecting device is arranged in the cold trap.

Technical Field

The invention belongs to the technical field of fluorine chemical industry, and particularly relates to trifluoromethyl fluoformate (FCOOCF)₃) And a production apparatus therefor.

Background

Fluorocarboxylic acid trifluoromethyl ester (FCOOCF)₃) Is a novel functional group fluorine-containing intermediate of low temperature resistant fluororubber. In the existing synthetic method, inflammable and explosive CO is required to be used, the safety is not high, and the yield of the target product is low (lower than 5 percent), so the method limits the total synthesisThe application of trifluoromethyl fluoroformate is disclosed.

CN103360245A discloses a method for synthesizing trifluoromethyl perfluoroformate, which comprises the steps of firstly, adding CO₂And fluorine gas is catalyzed by a catalyst at the temperature of 150-450 ℃ to obtain perfluoroformic acid (FCOOF); the resulting perfluoroformic acid is then reacted with trifluoroiodomethane (CF)₃I) Reacting at-50- -150 deg.C.

The reaction raw material used in the scheme is non-toxic and cheap carbon dioxide, the reaction process is relatively safe, and the cost is low; the conversion rate is higher than that of the existing synthesis method which adopts CO as a raw material; in addition, a specific process device is adopted, the flow is simplified, and the method is suitable for large-scale industrial production.

However, the above synthesis method has the following disadvantages: 1) the process route relates to fluorine gas in raw materials, has strong activity and toxicity, has high requirements on equipment and short service life of the equipment; 2) the reaction temperature for preparing the perfluoroformate by the process is 150-450 ℃, and the fluorine gas has higher requirements on equipment under the working conditions; 3) the overall conversion rate of the process is only about 15 percent; the best yield is 16%, and the purity is 21.6%.

In view of the above, the present invention is particularly proposed.

Disclosure of Invention

In order to overcome the technical problem, the invention provides trifluoromethyl fluoroformate (FCOOCF)₃) The novel process for the preparation of (1). The preparation method has the advantages of small toxic gas of raw materials, safer production, fewer process steps, milder process conditions, high yield, relatively lower requirement on equipment and the like.

The preparation method of trifluoromethyl fluoroformate comprises the following steps: the fluorine-containing reagent is used as a solvent, hexafluoropropylene and oxygen are used as reaction raw materials, and the reaction is initiated by ultraviolet light to generate the trifluoromethyl fluoroformate.

According to the invention, hexafluoropropylene and oxygen are used as raw materials, and the trifluoromethyl fluoroformate is synthesized by a one-step method under ultraviolet light initiation, so that the reaction is simpler; in addition, the invention can reduce monomer loss, accelerate reaction process and improve conversion rate by selecting fluorine-containing reagent as solvent.

According to some embodiments of the present invention, the fluorine-containing agent is selected from one or more of fluorine-containing hydrocarbon compounds, fluorine-chlorine hydrocarbon compounds, perfluoro ether compounds, etc., such as perfluoropropane, trifluorotrichloroethane, perfluorodimethyl ether, perfluorodiethyl ether, etc., which can be recycled; preferably one or more of perfluoropropane, trifluorotrichloroethane or perfluorodimethyl ether. Research shows that the fluorine-containing reagent is preferable, so that the loss of the monomer can be further reduced, the reaction process is accelerated, and the conversion rate is improved.

Preferably, the fluorine-containing reagent is pre-cooled to-35 to-25 ℃ before use.

According to some embodiments of the present invention, the hexafluoropropylene purity is required to be above 99.0%, although the higher the purity the better. In addition, there is a relatively strict requirement for controlling the moisture in the hexafluoropropylene, which is extremely harmful to the reaction and may destroy the molecular structure of the product produced, so it is preferable to control the moisture in the hexafluoropropylene to be 100ppm or less, although the lower the moisture is, the better the moisture is.

According to some embodiments of the invention, in the preparation method, the feeding speed of the hexafluoropropylene is 1.0-8.0L/h, preferably 2-5L/h; the introduction speed of the oxygen is 2-10L/h, and preferably 3-6L/h.

In one embodiment of the present invention, the ratio of the flow rate of the hexafluoropropylene to the flow rate of the oxygen is (0.8-1.5):1, preferably (0.9-1.2): 1.

According to some embodiments of the present invention, the ultraviolet light has a light source wavelength ranging from 100nm to 400nm, but preferably ranging from 180nm to 300 nm. The studies show that the energy ratio of the monomer used for the reaction and O is higher when using UV light of shorter wavelength₂The chemical bond energy of (2) is large; after absorbing ultraviolet energy with certain wavelength, the monomers form an excited state, and then are decomposed into free radicals to initiate free radical reaction, so that the compound is generated, and the reaction is more favorably carried out.

According to some embodiments of the invention, the reaction is carried out under cryogenic conditions; the temperature is preferably lower than-25 ℃, otherwise, the reaction is influenced by excessive by-products, of course, the reaction effect is better at the temperature lower than-35 ℃, and the reaction effect is best at the temperature lower than-55 ℃; however, too low a temperature also lowers the conversion rate of the reaction, greatly affecting the yield, and therefore it is necessary to ensure that the reaction temperature is not lower than-70 ℃, i.e., the reaction temperature is-70 to-25 ℃, preferably-70 to-35 ℃, and more preferably-70 to-55 ℃.

In order to improve the utilization rate of hexafluoropropylene, the hexafluoropropylene which is not completely reacted is subjected to reflux condensation, and the temperature of the reflux condensation is controlled to be between-40 ℃ and-20 ℃, preferably between-30 ℃ and-25 ℃.

In order to better collect the product trifluoromethyl fluoroformate, the prepared trifluoromethyl fluoroformate is liquefied at a low temperature, and the low-temperature liquefaction temperature is controlled to be-100-30 ℃, preferably-60-40 ℃.

The invention also provides a device for realizing the preparation method, which comprises the following steps: a reaction kettle; a reflux condenser connected with the reaction kettle; a cold trap connected to the reflux condenser; and a product collecting device is arranged in the cold trap.

The invention has the following beneficial effects:

the preparation method of the trifluoromethyl fluoroformate has the advantages of high yield, few byproducts, low production cost, low risk and the like.

Drawings

FIG. 1 is a schematic structural diagram of a device for preparing trifluoromethyl fluoroformate according to the present invention.

Detailed Description

The following examples are intended to illustrate the invention but are not intended to limit the scope of the invention.

The preparation device adopted by the invention comprises:

a stainless steel stirring reaction kettle with the volume of 2L is internally provided with an ultraviolet lamp with the wavelength of 200 nm;

a reflux condenser which is connected with the reaction kettle and has the lowest temperature of-70 ℃ below zero, wherein the temperature is controlled to be-30 to-25 ℃;

a cold trap connected to the reflux condenser; the cold trap is internally provided with a steel cylinder, and the temperature in the cold trap is controlled to be-60 to-40 ℃.

Example 1

The embodiment provides a preparation method of trifluoromethyl fluoroformate, which comprises the following steps:

(1) 1.5L of perfluoropropane (solvent) pre-cooled to-30 ℃ is added into the pre-cooled reaction kettle; introducing metered oxygen (O) into the bottom of the reaction kettle₂)3L/h (standard state) and 2.5L/h (standard state) (purity 99.5%) of hexafluoropropylene (monomer);

(2) the reaction phase is maintained at a temperature of about-45 ℃ for 30 h.

(3) The steel receiving cylinder was taken out of the cold trap and weighed to obtain 218g of trifluoromethyl fluoroformate with a yield of 49.3%.

The trifluoromethyl fluoroformate obtained by rectification has the purity of 88.7 percent by gas chromatography analysis.

Example 2

The embodiment provides a preparation method of trifluoromethyl fluoroformate, which comprises the following steps:

(1) 1.2L of trifluorotrichloroethane (solvent) pre-cooled to-30 ℃ is added into the pre-cooled reaction kettle; introducing metered oxygen (O) into the bottom of the reaction kettle₂)3.5L/h (standard state) and 5L/h (standard state) of hexafluoropropylene (monomer) (purity 99.5%);

(2) the reaction phase is maintained at a temperature of about-45 ℃ for 20 h.

(3) The steel cylinder was taken out of the cold trap and weighed to obtain 298g of trifluoromethyl fluoroformate with a yield of 50.6%.

The trifluoromethyl fluoroformate obtained by rectification has the purity of 89.4 percent by gas chromatography analysis.

Example 3

The embodiment provides a preparation method of trifluoromethyl fluoroformate, which comprises the following steps:

(1) 1.6L of perfluorinated dimethyl ether (solvent) pre-cooled to-30 ℃ is added into the pre-cooled reaction kettle; introducing metered oxygen (O) into the bottom of the reaction kettle₂)3L/h (standard state) and 4L/h (standard state) (purity 99.5%) of hexafluoropropylene (monomer);

(2) the reaction phase was maintained at a temperature of about-45 ℃ for 18 h.

(3) The steel cylinder is taken out from the cold trap and weighed to obtain 204g of trifluoromethyl fluoroformate, and the yield is 48.1%.

The trifluoromethyl fluoroformate obtained by rectification has the purity of 86.9 percent by gas chromatography analysis.

Comparative example

The yield of example 4 in CN103360245A was 16% and the purity was 21.6%.

Although the invention has been described in detail hereinabove with respect to a general description and specific embodiments thereof, it will be apparent to those skilled in the art that modifications or improvements may be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.