CN107778150B

CN107778150B - Method for preparing perfluoroisopropyl ethyl ketone

Info

Publication number: CN107778150B
Application number: CN201610719011.4A
Authority: CN
Inventors: 张鸣; 刘波; 杨旭仓; 李俊玲; 李斌; 陈炯
Original assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd
Current assignee: Zhonghao Chenguang Research Institute of Chemical Industry Co Ltd
Priority date: 2016-08-24
Filing date: 2016-08-24
Publication date: 2020-01-10
Anticipated expiration: 2036-08-24
Also published as: CN107778150A

Abstract

The invention relates to a method for preparing perfluoroisopropyl ethyl ketone, which takes perfluoropropylene and oxygen as raw materials and fluoride salt as a catalyst to react under the condition of ultraviolet irradiation to obtain the perfluoroisopropyl ethyl ketone. The method for preparing the perfluoro isopropyl ethyl ketone can obtain the product by adopting one-step reaction, is simple and easy to implement, has easily obtained raw materials, low price, less side reactions and mild reaction conditions, and is beneficial to large-scale industrial production.

Description

Method for preparing perfluoroisopropyl ethyl ketone

Technical Field

The invention relates to the field of chemical production, in particular to fluorine-containing fine chemical synthesis, and specifically relates to a method for preparing perfluoroisopropyl ethyl ketone.

Background

Perfluoro isopropyl ethyl ketone, perfluoro-2-methyl-3-pentanone, structural formula:

it is colorless transparent liquid at normal temperature and pressure, has boiling point of 49 deg.C, solidifying point of-108 deg.C, and density of 1.6g/mL at 25 deg.C under 1 atmosphere, and is immiscible with water.

The perfluoro isopropyl ethyl ketone as a halogenated hydrocarbon has excellent flame retardant property, is excellent in environmental protection, meets the requirement of pursuing sustainable development of human society, and has a wide development prospect.

Magnesium alloy is extremely easy to oxidize and burn in the smelting and processing processes, in order to solve the problem, most magnesium processing enterprises adopt gas protection smelting, and the most widely applied protective gas at present is sulfur hexafluoride (SF)₆). SF6 is a colorless, odorless and nontoxic gas, and a dense oxide film containing MgF2 is generated on the liquid surface of the magnesium alloy to prevent the magnesium alloy liquid from being further oxidized. However, SF6 is a greenhouse gas and can cause great harm to the global environment, the international magnesium cooperation plans to search for a substitute of SF6 from the end of the 20 th century, under the background, a plurality of companies and scientific research institutions carry out research and development work on the substitute of SF6, and among a plurality of substitutes, the environmentally-friendly substitute of perfluoroisopropyl ethyl ketoneThe performance is most ideal. The perfluoro isopropyl ethyl ketone can generate thermal decomposition on the surface of the magnesium alloy with the melting temperature higher than 575 ℃, and generate CO and fluorocarbon radicals, wherein the fluorocarbon radicals have high reactivity and are necessary to MgF2 and CO2 for generating a protective film by reacting with the unprotected magnesium surface and magnesium vapor. In unsealed casting operations, the perfluoroisopropyl ethyl ketone can react completely in contact with fresh liquid magnesium to form a protective substance. Once the protective film is formed, the magnesium participating in the reaction is reduced, and the excess fluorine-containing radicals generate Perfluorocarbons (PFCs) and fluorine-containing paraffins (F-Olefins) in a side reaction manner. These by-products are harmful to the environment and operators (PFCs have high GWP values, some fluorine-containing paraffin is toxic, but if the mixed gas has enough oxygen or the concentration of perfluoro isopropyl ethyl ketone is low, all fluorine-containing radicals can participate in the reaction, and PFCs and fluorine-containing paraffin are hardly found in the exhaust gas. in the magnesium smelting protection test in industrial production scale, it is shown that the perfluoro isopropyl ethyl ketone has the same good effect as SF6 as a protective agent, and compared with SF6, perfluoro isopropyl ethyl ketone is more unstable and reacts with magnesium more easily to form MgF2 film, and the perfluoro isopropyl ethyl ketone has higher fluorine-containing rate of its molecule, and compared with a substance with low fluorine-containing rate, the melt surface has more F atoms and is more easily to form MgF2 protective film.

From the 50 s of the 20 th century to the beginning of the 21 st century, the Halon fire extinguishing agent is always the first choice of the fire department due to the excellent fire extinguishing performance, but chlorine and bromine atoms generated during the fire extinguishing of the Halon are toxic and harmful substances and have a certain destructive effect on the atmospheric ozone layer, under the circumstance, the Halon is gradually eliminated, and China has been completely prohibited from using the Halon fire extinguisher in 2005. Among the various halons, perfluoro isopropyl ethyl ketone shows strong competitiveness in the aspects of fire extinguishing performance and environmental protection. The perfluoro isopropyl ethyl ketone is liquid at room temperature, can be quickly gasified during fire extinguishing, and is suitable for a total-flooding gas fire extinguishing system. The product has low toxicity, high safety on the premise of ensuring the fire extinguishing efficiency, and is suitable for places with people. The perfluoro isopropyl ethyl ketone is non-conductive and has no residue, and because the temperature of a protection area can not be rapidly reduced in a short time like carbon dioxide during spraying, the perfluoro isopropyl ethyl ketone can not generate cold shock and cold quenching effects on precision equipment and precious belongings, and can not absorb a large amount of heat from the periphery, so that water vapor in the air is greatly condensed, and the phenomenon of condensation is generated to damage an integrated circuit and a chip, thereby being suitable for protecting the precision and precious electronic equipment. The good performances of the perfluoroisopropyl ethyl ketone determine that the perfluoroisopropyl ethyl ketone has wide application prospects in important places such as manned telecommunication rooms, computer and electric control rooms, chemical dangerous goods cargo holds, cockpit and engine compartments of ground fighting vehicles, engine compartments and power compartments of airplanes. Because the perfluoro isopropyl ethyl ketone is liquid at room temperature, the perfluoro isopropyl ethyl ketone can be safely stored and transported (including air transportation) in a wider temperature range by using a common container under the normal pressure state, and does not need to be stored and transported by using a pressure container like a halon substitute, thereby greatly facilitating the refilling of a fixed gas fire extinguishing system. The perfluoro isopropyl ethyl ketone overcomes the problems of greenhouse effect and climate influence of the fluorinated alkane fire extinguishing agent, so that the perfluoro isopropyl ethyl ketone is a new generation of clean fire extinguishing agent which can be used for a long time and replaces halon and fluorinated alkane synthetic fire extinguishing agents, and can be widely applied.

Perfluoroisopropyl ethyl ketone can be used as a wet cleaning agent to clean steam reactors and their components, build-up in gas phase reactors, and various impurities that can become incorporated in gas phase reactors. The conventional cleaning agents include hydrocarbon cleaning agents such as acetone and isopropyl ketone, and fluorine-containing chemical agents such as perfluorocarbon and perfluoronitrogen compounds. Hydrocarbon cleaning agents are difficult to effectively treat fluoropolymers, and conventional fluorine-containing agents tend to cause environmental pollution. The perfluoro isopropyl ethyl ketone overcomes the defects of the traditional cleaning agent, and has obvious cleaning effect and good environmental protection performance.

At present, various methods are used for synthesizing the perfluoroisopropyl ethyl ketone, and the following methods are commonly used.

Patent document US6478979B1 uses hexafluoropropylene reacted with perfluoropropionyl fluoride, diglyme as solvent and active potassium fluoride as catalyst. The mass fraction of the perfluoro isopropyl ethyl ketone in the crude product of the reaction reaches more than 90 percent, the yield to hexafluoropropylene is 99 percent, the yield to perfluoro propionyl fluoride is 80 percent, the yield and the selectivity of the route are both good, but the perfluoro propionyl fluoride which is the raw material of the reaction is not produced industrially. The method is therefore limited to laboratory preparations.

Fenichev et al (Russian Journal of Applied Chemistry; vol.86; nb.3; (2013); p.376-386) describe a process for the preparation of hexafluoropropene and hexafluoropropylene oxide by reaction with diglyme and acetonitrile as solvents and active potassium fluoride as catalyst. This document describes that this process is much produced with a dimer of hexafluoropropylene and perfluoro-3-hexanone, and is difficult to be industrially implemented due to the difficulty in separation due to the close boiling point.

Zappevalov et al (Zhurnal organic heskoi Khimii; vol.22; nb.1; (1986); p.93-99) use perfluorocyclohexene oxide isomerization to give perfluoroisopropyl ethyl ketone in high yields, but the perfluoroepoxy compound itself is difficult to obtain and therefore the process is very limited.

Rogovik et al (Bulletin of the Academy of Sciences of the USSR, Division of chemical Science (English transition); vol.39; nb.9.1.; 1990); p.1870-1876;) have also limited the ability to obtain perfluoroisopropylethyl ketone by decomposition using a fluorosulfonic acid, with a conversion of 16%, a yield of 76%, and difficulty in obtaining the starting material.

In addition, there are synthesis routes such as the reaction method of perfluorocarboxylic acid salt and perfluoroacid anhydride (see patent documents US5466877 and US4136121 for details), but all have the disadvantages of difficult availability of reaction raw materials, high cost and the like, and industrial production is difficult to realize.

With the continuous development of society, the demand of perfluoroisopropyl ethyl ketone on fire extinguishing agents, fire retardants, cleaning agents and the like can be ensured to be continuously increased, so that a novel efficient method for industrially producing perfluoroisopropyl ethyl ketone is necessary.

Disclosure of Invention

In order to overcome the defects of the prior art, the invention provides a method for preparing perfluoroisopropyl ethyl ketone, which is simple, convenient and feasible and is suitable for industrial production.

The method provided by the invention takes perfluoropropene and oxygen as raw materials, takes fluoride salt as a catalyst, fully reacts under the condition of ultraviolet irradiation, and obtains the perfluoroisopropyl ethyl ketone through one-step reaction.

Specifically, the method comprises the following steps: replacing air in the reaction container with nitrogen or inert gas, adding perfluoropropene, fluoride salt and a solvent into the reaction container, and heating and keeping the temperature in the reaction container to be 40-80 ℃; starting ultraviolet irradiation, intermittently introducing oxygen and keeping the pressure in the reaction container to be 1-2 MPa, and fully reacting to obtain the catalyst.

In the reaction of the invention, the catalyst is selected from fluoride salt, preferably potassium fluoride or cesium fluoride.

In the reaction of the present invention, the solvent is an alcohol ether solvent, preferably diethylene glycol dimethyl ether, diethylene glycol monomethyl ether, diethylene glycol diethyl ether or tetraethylene glycol dimethyl ether, and more preferably diethylene glycol dimethyl ether.

In order to realize the synergistic effect among the components and improve the reaction efficiency, the use amount of the components is optimized. Specifically, the weight ratio of the fluoride salt to the solvent is 0.1-10: 100, preferably 1-5: 100. preferably, the weight ratio of the perfluoropropene to the fluoride salt to the solvent is 550-650: 16-20: 750 to 850 g. More preferably, the weight ratio of the perfluoropropene, the fluoride salt, the solvent and the oxygen is 550-650: 16-20: 750-850: 35-45.

The reaction of the present invention is carried out under mild and easily controlled conditions of temperature and pressure. Wherein the reaction temperature is preferably 50-70 ℃, and more preferably 60-70 ℃.

In order to ensure that the reaction system of the raw materials, the catalyst and the solvent can realize sufficient reaction, promote the reaction to be efficiently carried out and avoid side reaction, the invention carries out ultraviolet irradiation while introducing oxygen for reaction. The wavelength of the ultraviolet rays is 200-380 nm, and preferably 250-260 nm.

As a preferred aspect of the present invention, the method comprises the steps of: replacing air in a reaction container with nitrogen, adding 580-620 parts of perfluoropropene, 16-20 parts of potassium fluoride/cesium and 780-820 parts of diethylene glycol dimethyl ether into the reaction container, and heating and keeping the temperature in the reaction container at 60-70 ℃; starting ultraviolet irradiation with the wavelength of 253-255 nm, intermittently introducing 38-42 parts of oxygen, keeping the pressure in the reaction container at 1-2 MPa, and fully reacting to obtain the catalyst.

In the synthesis process of the invention, trace moisture can seriously affect the reaction effect, generate a large amount of byproducts and even corrode equipment, so that the container of the reaction is dried, and the water content of each raw material in the reaction is below 10 ppm.

In order to obtain perfluoroisopropyl ethyl ketone more suitable for industrial application, the reaction process further comprises: and standing and layering the product obtained by the reaction, taking the lower-layer liquid, and performing alkali washing and water washing treatment to obtain the catalyst.

The method for preparing the perfluoro isopropyl ethyl ketone can obtain the product by adopting one-step reaction, is simple and easy to implement, has easily obtained raw materials, low price, less side reactions and mild required temperature and pressure conditions, and is beneficial to industrial production.

Detailed Description

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

Example 1

A pressure-resistant jacketed steel reactor having a volume of 2000ml was equipped with an ultraviolet lamp (wavelength 254nm) irradiation apparatus having a power of 125W, and the reactor was equipped with a stirring apparatus.

Strictly drying the reactor, replacing air in the reactor with nitrogen, adding 600g of perfluoropropene HFP, 8g of potassium fluoride and 800g of diethylene glycol dimethyl ether into the reactor, and heating and keeping the temperature in the reactor at 50 ℃;

starting ultraviolet irradiation with the wavelength of 254nm, intermittently introducing 40g of oxygen, keeping the pressure in the reaction container at 1MPa, and fully reacting for 5 hours;

and standing and layering the product obtained by the reaction, taking the lower-layer liquid, and performing alkali washing and water washing treatment to obtain 286g of the product.

The content of perfluoroisopropyl ethyl ketone in the product is 61% by gas chromatography detection.

Example 2

Compared with example 1, the difference is only that: 16g of potassium fluoride are used, the reaction temperature being 60 ℃.

Example 3

Compared with example 1, the difference is only that: 20g of potassium fluoride are used, the reaction temperature being 70 ℃.

Example 4

Compared with example 1, the difference is only that: 16g of cesium fluoride are used, the reaction temperature being 60 ℃.

Example 5

Compared with example 1, the difference is only that: 20g of cesium fluoride are used, the reaction temperature being 70 ℃.

Example 6

Compared with example 1, the difference is only that: 800g of diethylene glycol diethyl ether were used.

The operation conditions, the weight, the purity and the yield of the reaction products in examples 1 to 6 were counted. The results are shown in Table 1.

Table 1: operating conditions and product weight, purity and yield

The invention ensures that the reaction can be carried out quickly and efficiently by optimizing the reaction process and optimizing the reaction raw materials and specific parameters, can complete the reaction within about 5 hours, has few side reactions and mild required temperature and pressure conditions, and is beneficial to industrial production.

Although the invention has been described in detail hereinabove by way of general description, specific embodiments and experiments, it will be apparent to those skilled in the art that many modifications and improvements can be made thereto based on the invention. Accordingly, such modifications and improvements are intended to be within the scope of the invention as claimed.

Claims

1. A method for preparing perfluoroisopropyl ethyl ketone is characterized by comprising the following steps: replacing air in a reaction container with nitrogen, adding 580-620 parts of perfluoropropene, 16-20 parts of cesium fluoride and 780-820 parts of diethylene glycol dimethyl ether into the reaction container, and heating and keeping the temperature in the reaction container at 60-70 ℃; starting ultraviolet irradiation with the wavelength of 250-260 nm, intermittently introducing 38-42 parts of oxygen, keeping the pressure in the reaction container at 1-2 MPa, and fully reacting to obtain the catalyst.

2. The method according to claim 1, characterized in that the vessel of the reaction is subjected to a drying treatment; the water content of each raw material in the reaction is less than 10 ppm.

3. The method of claim 1 or 2, wherein the reaction process further comprises: and standing and layering the product obtained by the reaction, taking the lower-layer liquid, and performing alkali washing and water washing treatment to obtain the catalyst.