JPS6319501B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Field of the Invention The present invention relates to a conventional method for producing perfluoro(N,N-dimethylvinylamine). More specifically, the present invention enables the easy production of perfluoro(N,N-dimethylvinylamine), which is useful as a synthetic intermediate or polymeric monomer for fluorine-containing products such as surfactants, agricultural chemicals, and pharmaceuticals. The present invention relates to an economical manufacturing method with high yield using available raw materials.

Background Art In recent years, fluorine-containing olefin compounds have been in the spotlight as synthetic intermediates and raw materials for various fluorine-containing products, such as surfactants, agricultural chemicals, pharmaceuticals, etc. Widely used as a monomer for polymer production.

By the way, in perfluoro(N,N-dimethylvinylamine) represented by the formula ( _CF3 ) _2NCF = _CF2 ...(), a perfluorodimethylamino group is bonded to one of the carbon atoms in the double bond, Therefore, by using this compound as an intermediate raw material, it is possible to produce various useful compounds containing the perfluorodimethylamino group. Furthermore, by copolymerizing the compound with other fluoroolefins and introducing perfluorodimethylamino groups into the polymer, it is possible to reduce the crystallinity and improve the mechanical properties of the polymer. As described above, perfluoro(N,N-dimethylvinylamine) is an extremely useful compound as a synthetic intermediate or a raw material for producing fluorine-containing polymers.

This perfluoro(N,N-dimethylvinylamine) is an already known compound, and has been produced until now through a two-step process as shown below (US Pat. No. 3,311,599).

That is, in the first stage process, the reaction formula Accordingly, N-chlorobis(trifluoromethyl)amine and trifluoroethylene are subjected to a radical reaction under ultraviolet irradiation to produce a 1:1 adduct.

Next, in the second step process, the reaction formula Accordingly, the 1:1 adduct obtained in the above step is subjected to a dehydrochlorination reaction in the presence of powdered potassium hydroxide to produce the desired perfluoro(N,N-dimethylvinylamine) ().

However, according to this method, in the reaction for producing the 1:1 adduct shown in reaction formula (A), the overall conversion rate is poor (50%), and the desired N-(2-
In addition to chloro-2,2,1-trifluoroethyl)bis(trifluoromethyl)amine (), N-(2-chloro-1,1,2-trifluoroethyl)bis(trifluoromethyl) is an isomer. There is a drawback that amine () is produced as a significant by-product (compound ():() production ratio according to gas chromatography peak area = 84:14), and also in the dehydrofluorination reaction shown in reaction formula (B), the conversion low rate (55-60
%).

Furthermore, the starting material N-chlorobis(trifluoromethyl)amine () can be obtained by the reaction of bis(trifluoromethyl)amine [(CF ₃ ) ₂ NH] with chlorine (U.S. Pat. No. 3,052,723). ), the production of bis(trifluoromethyl)amine has problems such as the complicated process and the need for many reagents, equipment, and time.

As described above, the conventional method for producing perfluoro(N,N-dimethylvinylamine) has various drawbacks and cannot be said to be suitable as an industrial production method.

Problems to be Solved by the Invention Under these circumstances, the object of the present invention is to obtain perfluoro(N,N-dimethylvinylamine) which is useful as a synthetic intermediate or a monomer for producing fluorinated polymers. ) by a simple process and in high yield using readily available raw materials.

Means for Solving the Problems As a result of extensive research in order to achieve the above object, the present inventors found that perfluoro (2-dimethylaminopropionyl fluoride) or penfluoro (2-dimethylaminopropionyl fluoride) was used as a raw material. The inventors have discovered that the objective can be achieved by using and thermally decomposing the same, and based on this knowledge, they have completed the present invention.

That is, the present invention provides the general formula (In the formula, X is F or OM, and M is an alkali metal or alkaline earth metal ion corresponding to a monovalent ion). The present invention provides a method for producing perfluoro(N,N-dimethylvinylamine) represented by the formula ( _CF3 ) _2NCF = _CF2 ...().

In the method of the present invention, a perfluoro compound represented by the above general formula (), namely perfluoro(2-dimethylaminopropionyl fluoride) or perfluoro(alkali metal salt or alkaline earth metal salt of 2-dimethylaminopropionic acid) is used as a raw material. is used. The former perfluoro(2-dimethylaminopropionyl fluoride) is easily obtained, for example, by electrolytic fluorination of a reactive derivative of 2-dimethylaminopropionic acid, preferably methyl ester, in liquid hydrogen fluoride. Also, the latter perfluoro(2-
Dimethylaminopropionate) is obtained by reacting the thus obtained perfluoro(2-dimethylaminopropionyl fluoride) with an alkali metal or alkaline earth metal hydroxide.

In the method of the present invention, the target perfluoro(N,N-dimethylvinylamine) represented by the formula (CF ₃ ) ₂ NCF=CF ₂ ...() is obtained by simply heating the perfluoro compound represented by the general formula (). Easily obtained by decomposition. Perfluoro compounds used as raw materials include perfluoro(2-dimethylaminopropionyl fluoride), perfluoro(sodium 2-dimethylaminopropionate), and perfluoro(potassium 2-dimethylaminopropionate) because the thermal decomposition reaction proceeds easily. ) is preferred.

As the temperature for thermal decomposition, a temperature in the range of 100 to 500°C, preferably 100 to 300°C is selected. If this temperature is too high, side reactions such as decomposition are likely to occur, and if this temperature is too low, the conversion rate will decrease. The reaction time varies depending on the reaction temperature, but is usually in the range of 10 seconds to 2 hours. When a high reaction temperature is selected, the reaction time becomes short, and when a low reaction temperature is selected, the reaction time becomes long.

In this thermal decomposition reaction, the reaction pressure is not an important factor, and the reaction can be carried out under reduced pressure, atmospheric pressure, or elevated pressure, but the reaction products are relatively easy to recover. From this point of view, it is preferable to carry out the reaction under atmospheric pressure or reduced pressure.
Further, the thermal decomposition reaction may be carried out using an inert gas such as nitrogen, helium, argon, or carbon dioxide, or an aprotic liquid compound such as polyethers as a diluent, depending on the reaction form. In this case, the dilution ratio is preferably 100 times or less.

Furthermore, in the thermal decomposition reaction, it is important that all materials used in the reaction do not contain water. In the presence of water or other proton-donating substances,
N,N-bis(trifluoromethyl)-1,2,
Since 2,2-tetrafluoroethylamine [CF ₃ CHFN(CF ₃ ) ₂ ] is produced as a by-product, the yield of desired perfluoro(N,N-dimethylvinylamine) decreases.

In the method of the present invention, perfluoro(2-dimethylaminopropionyl fluoride) is used as a raw material.
When using a metal salt or metal oxide, it is preferable to carry out the thermal decomposition reaction in the presence of a metal salt or metal oxide. In this case, the desired perfluoro(N,N-dimethylvinylamine ) is obtained.
There are no particular restrictions on the material of the pyrolysis reactor, but stainless steel or Hastelloy is usually used. There is no particular restriction on the type of the packed bed, and any type such as a fixed bed, moving bed, or fluidized bed can be used.

Examples of the metal salt include sodium carbonate,
Potassium carbonate, lithium carbonate, sodium phosphate, potassium phosphate, barium carbonate, calcium carbonate, magnesium carbonate, potassium sulfate, sodium sulfate, etc.; examples of metal oxides include zinc oxide, cadmium oxide, etc.; Solid bases such as sodium carbonate and potassium carbonate are toxic substances generated in thermal decomposition reactions.
It is particularly suitable because it can decompose COF ₂ .

Effects of the Invention According to the method of the present invention, perfluoro(N,N-
The method is suitable for perfluoro(N,N-
It is useful as an industrial method for producing dimethylvinylamine).

In addition, the obtained perfluoro(N,N-dimethylvinylamine) can be suitably used as a synthetic intermediate for fluorine-containing products such as surfactants, agricultural chemicals, and pharmaceuticals, and as a monomer for producing fluorine-containing polymers. It will be done.

Examples Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 As a raw material, a product obtained by electrolytic fluorination of methyl 2-dimethylaminopropionate was distilled to remove most of the low-boiling compounds, and the remaining crude product was used. Perfluoro(2-
The content of dimethylaminopropionyl fluoride was 69.5% by weight.

First, 200ml with reflux condenser and dropping funnel
20.8 g of the crude product [perfluoro (containing 14.5 g of 2-dimethylaminopropionyl fluoride)] and 30 ml of water were placed in a three-necked flask, and phenolphthalein was added thereto as an indicator, followed by magnetic stirring. While cooling on ice, a concentrated aqueous potassium hydroxide solution was added dropwise to neutralize the mixture until it became slightly alkaline.

Next, transfer the contents to a 200 ml eggplant flask and use a rotary evaporator to cool the mixture to 50°C.
When the water was removed under reduced pressure using an aspirator while heating, a white solid was precipitated. It was further held at 50°C for about 8 hours to perform vacuum drying.

After pulverizing the white solid substance in the flask obtained in this way and connecting a gas introduction pipe to the upper part of the flask, the flask was heated in an oil bath while flowing helium gas at a rate of 80 ml/min.
The temperature was slowly raised from 150°C to 190°C over a period of minutes, and the temperature was maintained for an additional hour to carry out a thermal decomposition reaction. The product was condensed and collected in a trap cooled to -78°C. The collected fluorocarbons are
It was 9.5g.

This material is used for gas chromatography [liquid phase:
1,6-bis(1,1,12-trihydroperfluorododecyloxy)hexane, carrier: 60-80 mesh chromosorb PAW, carrier: helium], IR, ¹⁹ FNMR, Mass, etc. analysis revealed that most of the was perfluoro(N,N-dimethylvinylamine), and the others were N,N-bis(trifluoromethyl)-1,2,2,2-tetrafluoroethylamine.

The amount of perfluoro(N,N-dimethylvinylamine) was 8.9 g, and the yield was 78.9%. Furthermore, this compound is gaseous at room temperature, and its boiling point was determined by extrapolation from vapor pressure measurements.
The temperature was 13.7°C (literature value 17-18°C). The identification of the compound was based on the following spectroscopic data.

^19F NMR data Chemical shift (ppm: CFCl ₃ standard) −97.3 (d, d) −110.9 (d, d) −144.3 (d, d) −58.3 Coupling constant (Hz) −=49, −=53, −=114 Mass Analysis data m/z 233 M ⁺ 214 [MF] ⁺ 145 C ₃ F ₅ N ⁺ Infrared spectrum data 1812 cm ^- (CF ₂ = CF-) Example 2 Instant evaporator for vaporizing raw materials and dilution gas A horizontal reactor was constructed using a stainless steel tube with a length of 48.0 cm and an inner diameter of 2.5 cm, with a flow rate control device connected to the inlet side and a low-temperature trap to condense and collect the reaction products on the outlet side. In this reactor, 82.6 g of powdered potassium carbonate was filled horizontally to approximately the middle of the reactor, and both ends were filled with metal wool.

First, the reactor was kept at 200° C. and helium gas was allowed to flow at 50 ml/min. Next, a fluorocarbon mixture [purity of perfluoro(2-dimethylaminopropionyl fluoride): 90.8
%] was supplied to the flash evaporator using a micro metering pump for 30 minutes, and after being vaporized and mixed with the helium gas that was quantitatively supplied, it was introduced into the reactor, while the product was condensed and collected in a trap cooled to -78°C on the outlet side.

As a result, 4.64 g of fluorocarbon was obtained,
When analyzed in the same manner as in Example 1, it was found that perfluoro(N,N-dimethylvinylamine)
It contained 4.00g. The conversion rate is 100%,
The yield was 82.6%.

Example 3 Using the same reactor as in Example 2, it was filled with 85.4 g of powdered sodium carbonate, and a fluorocarbon mixture with a purity of 94.1% perfluoro(2-dimethylaminopropionyl fluoride) was used as a raw material, and further reaction was carried out. The reaction was carried out in the same manner as in Example 2, except that the temperature was 220°C.

5.71 g of the fluorocarbon mixture was fed into the reactor for pyrolysis over a period of 15 minutes, yielding 4.24 g of fluorocarbon in the cooling trap.

When this product was analyzed in the same manner as in Example 1, it was found that
Perfluoro(N,N-dimethylvinylamine)
It contained 3.97 g and 0.16 g of unreacted perfluoro(2-dimethylaminopropionyl fluoride).

The conversion rate was 97.0%, and the yield of the obtained perfluoro(N,N-dimethylvinylamine) was 97.8% based on the consumed perfluoro(2-dimethylaminopropionyl fluoride).

Example 4 Using the same reactor as in Example 2, 36.1 g of powdered zinc oxide was used, and perfluoro(2-dimethylaminopropionyl fluoride) was used as the raw material.
The reaction was carried out in the same manner as in Example 2, except that a fluorocarbon mixture with a purity of 94.1% was used and the reaction temperature was 300°C.

11.73 g of the fluorocarbon mixture was fed to the reactor for pyrolysis over a period of 19 minutes, leaving 8.60 g of fluorocarbon in the cooling trap.

When this product was analyzed in the same manner as in Example 1, it contained 1.55 g of perfluoro(N,N-dimethylvinylamine) and 4.72 g of unreacted perfluoro(2-dimethylaminopropionyl fluoride).

The conversion rate was 42.8%, and perfluoro(N,N
-dimethylvinylamine) was 42.4% based on the consumed perfluoro(2-dimethylaminopropionyl fluoride).

Claims (1)

[Claims] 1. General formula (In the formula, X is F or OM, and M is an alkali metal or alkaline earth metal ion corresponding to a monovalent ion). A method for producing perfluoro(N,N-dimethylvinylamine) represented by the formula (CF ₃ ) ₂ NCF=CF ₂ .