JP3765172B2 - Method for producing fluorinated ether - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing various fluorinated ethers. The various fluorinated ethers produced according to the present invention are useful as dry etching gas instead of perfluorocarbon (PFC).
[0002]
[Prior art and problems to be solved by the invention]
Conventionally, various PFCs have been used as the dry etching gas. However, these gases are extremely stable in the atmosphere and have a high global warming potential, so that it is desired to reduce the emission amount. For this reason, recently, fluoroether compounds have attracted attention as dry etching gases. Since the fluorinated ether produced according to the present invention has an ether bond, it is easily decomposed in the atmosphere and is considered suitable as a dry etching gas.
[0003]
Okajima et al. Discloses a method in which a compound having a CH ₃ group is fluorinated in the presence of iron, copper, zinc, nickel, tin, chromium or the like in JP-A-1-80838. Scherer et al., JP-A-61-186338, discloses a method for synthesizing various perfluoroalkyl ethers in which fluorination is carried out in perfluorohexane or Freon 113 under light irradiation conditions.
[0004]
Among various fluorinated ethers according to the present invention, for example, a conventional method for producing CF ₃ OCF ₂ CHF ₂ includes (1) a mixture of CF ₃ OCF ₂ CHF ₂ by electrolytic fluorination of β-methoxypropionic acid esters. (Berenblit, Et al., Zh. Org. Khim., 1976, 12,767), (2) CF ₃ OCF ₂ CF by thermal decomposition reaction (170 ° C.) of perfluoro (β-methoxypropionic acid sodium salt) ₂ H (Gubanov, et al., Zh. Obschch. Khim., 1964, 34, 2802), (3) CF ₃ OCF ₂ by electrolytic decarboxylation of perfluoro (sodium β-methoxypropionate) A method for obtaining CHF ₂ (Berenblit, Et al., Novoesti Elektrokhim. Org. Sedin. Tezsiy Dokl. Vses. Sovechch Elektrokhim., Org. Siedin. 8th. 1973, 31) is known. However, since these reactions are electrolytic reactions or thermal decomposition reactions, the yield is low (there is no description of the yield in the above paper (2), but generally the thermal decomposition reaction is generally low in yield) ). As a method for producing a fluorinated ether, a method for obtaining a fluorinated ether using hydrofluoroalkyl ether and fluorine gas at −40 to 0 ° C. is known (USP3897502). Is low.
[0005]
There are many known hydrogen-fluorine substitution reactions of organic compounds with fluorine gas, including Lagow et al. (J. Org. Chem., 42, 3437 (1977)). However, fluorine is extremely reactive, and there is a risk of runaway or explosion of the reaction. Therefore, a special reactor is required, and in order to prevent side reactions such as breaking of carbon-carbon bonds of organic compounds. This is not industrially satisfactory because it requires a low temperature of −78 ° C. and a large amount of dilution gas.
[0006]
An object of the present invention is to provide a method for producing a fluorinated ether having a high conversion rate and a small amount of by-products.
[0007]
[Means for Solving the Problems]
As a result of earnestly examining industrially useful production methods of various fluorinated ethers useful as a dry etching gas, the present inventors have obtained a reaction between 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas. It has been found that various fluorinated ethers can be obtained. Furthermore, as a result of earnest examination of the reaction between 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas, this reaction is a liquid phase reaction in the presence of hydrogen fluoride inert to fluorine gas, It has been found that any of a liquid phase reaction in the presence of an inert solvent other than hydrogen fluoride or a gas phase reaction under dilution of a gas inert to fluorine gas can be performed.
[0008]
That is, this invention provides the manufacturing method of the fluorinated ether as shown below.
[0009]
1. A process for producing a fluorinated ether, comprising reacting 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas in the presence of hydrogen fluoride.
[0010]
2. Item 2. The method according to Item 1, wherein the fluorine gas is diluted with a gas inert to the fluorine gas.
[0011]
3. Item 3. The above item 2, wherein the gas inert to the fluorine gas is at least one selected from the group consisting of nitrogen, helium, hydrogen fluoride, and perfluoroalkanes having 4 or less carbon atoms. Method.
[0012]
4). Fluorinated _{ether, CF 3 OCF 2 CF 3,} CF 2 HOCF 2 CF 3, CF 3 OCF 2 CF 2 H, CH 3 OCF 2 CF 3, CH 2 FOCF 2 CF 3, CF 2 HOCF 2 CF 2 H and CH Item _2. The method according to any one of Items 1 to 3, wherein the method is at least one selected from the group consisting of ₂ FOCF ₂ CF ₂ H.
[0013]
5. Fluorination characterized in that 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas are brought into contact with each other in the presence of a solvent other than hydrogen fluoride and inert to fluorine gas. A method for producing ether.
[0014]
6). 6. The method according to item 5, wherein the reaction temperature is 1 to 100 ° C.
[0015]
7). Item 7. The method according to Item 5 or 6, wherein the fluorine gas is diluted with a gas inert to the fluorine gas.
[0016]
8). Item 8. The solvent according to any one of Items 5 to 7, wherein the solvent inert to the fluorine gas is at least one selected from the group consisting of perfluoroalkanes, chlorofluoroalkanes, and perfluoropolyethers. The method described in 1.
[0017]
9. Item 7 or 8 above is characterized in that the gas inert to the fluorine gas is at least one selected from the group consisting of nitrogen, helium, hydrogen fluoride, and perfluoroalkanes having 4 or less carbon atoms. The method described.
[0018]
10. Fluorinated _{ether, CF 3 OCF 2 CF 3,} CF 2 HOCF 2 CF 3, CF 3 OCF 2 CF 2 H, CH 3 OCF 2 CF 3, CH 2 FOCF 2 CF 3, CF 2 HOCF 2 CF 2 H and CH Item 10. The method according to any one of Items 5 to 9, which is at least one selected from the group consisting of ₂ FOCF ₂ CF ₂ H.
[0019]
11. A fluorinated ether, which comprises reacting a 11.1,1,2,2-tetrafluoroethyl methyl ether and a fluorine gas in a gas phase under dilution with a gas inert to the fluorine gas. Manufacturing method.
[0020]
12 Item 12. The item 11, wherein the gas inert to the fluorine gas is at least one selected from the group consisting of nitrogen, helium, hydrogen fluoride, and perfluoroalkanes having 4 or less carbon atoms. Method.
[0021]
13. Fluorinated _{ether, CF 3 OCF 2 CF 3,} CF 2 HOCF 2 CF 3, CF 3 OCF 2 CF 2 H, CH 3 OCF 2 CF 3, CH 2 FOCF 2 CF 3, CF 2 HOCF 2 CF 2 H and CH Item 13. The method according to Item 11 or 12, wherein the method is at least one selected from the group consisting of ₂ FOCF ₂ CF ₂ H.
[0022]
DETAILED DESCRIPTION OF THE INVENTION
Examples of 1,1,2,2-tetrafluoroethyl methyl ether used in the production method of the present invention include, for example, Park, JD, Sharrah, ML, J. Am. Chem. Soc., Vol. 73, 1329 (1951). Those synthesized by the method described in 1. can be used.
[0023]
In the reaction of 1,1,2,2-tetrafluoroethyl methyl ether with fluorine gas, liquid phase reaction in the presence of hydrogen fluoride inert to fluorine gas, inert solvent other than hydrogen fluoride Either a liquid phase reaction in the presence or a gas phase reaction under dilution with a gas inert to fluorine gas can be used.
[0024]
When performing a liquid phase reaction in the presence of hydrogen fluoride, the fluorine gas supplied to the reaction system may be supplied alone, such as nitrogen, helium, hydrogen fluoride, or a perfluoroalkane having 4 or less carbon atoms. It may be diluted with a gas inert to the fluorine gas.
[0025]
As a preferred embodiment of the reaction, a semi-batch method in which hydrogen fluoride is charged into a reactor, 1,1,2,2-tetrafluoroethyl methyl ether is introduced, and fluorine gas is blown into the liquid to react, or Hydrogen fluoride is charged into the reactor, and 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas are continuously charged and reacted.
[0026]
The reaction temperature can be -30 ° C to 100 ° C, but it is preferably -10 ° C to 30 ° C. When the reaction is performed at a temperature higher than the boiling point of hydrogen fluoride, it is necessary to provide a condenser in the reactor so that hydrogen fluoride does not flow out of the reaction system.
[0027]
As the reaction pressure, it is usually desirable to carry out at atmospheric pressure, but in some cases, it can be carried out under reduced pressure or slightly pressurized conditions.
[0028]
Although it does not specifically limit as reaction time, 0.5 to 30 hours are preferable.
[0029]
The charged molar ratio of 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas (F ₂ ) is preferably 1: 1 to 1:10.
[0030]
The fluorinated ether obtained by the reaction is CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₃ , CF ₃ OCF ₂ CF ₂ H, CH ₃ OCF ₂ CF ₃ , CH ₂ FOCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₂ H, CH ₂ FOCF ₂ CF ₂ H and the like.
[0031]
When performing a liquid phase reaction in the presence of an inert solvent other than hydrogen fluoride, the contact between 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas is at least a solvent inert to fluorine gas. It is preferable to carry out under the condition in which one kind is present. Examples of solvents inert to fluorine gas include perfluoroalkanes such as perfluorocyclobutane, perfluorohexane, perfluorooctane, and perfluorodecane; perfluoropolyethers as shown in Lubricant Vol. 32, No. 2, page 107 Oil (for example, Daikin Kogyo Co., Ltd., demnam, Oushimont Co., Ltd., Fomblin, DuPont Co., Ltd. Krytox, etc.); Chlorofluoroalkanes such as, but not limited to, difluoroyl). Perfluoropolyether oil and chlorotrifluoroethylene oligomer oil are fluorine-based synthetic lubricating oils.
[0032]
In addition to the solvents described above, various chlorofluorocarbons (for example, CFC-113, etc.) can also be used, but they should not be used because they will destroy the ozone layer in the stratosphere when leaked into the atmosphere.
[0033]
The fluorine gas supplied to the reaction system may be supplied alone or diluted with a gas inert to fluorine gas such as nitrogen, helium, hydrogen fluoride, perfluoroalkane having 4 or less carbon atoms. Good.
[0034]
As a preferred mode of the reaction, at least one of the above solvents is charged into a reactor, 1,1,2,2-tetrafluoroethyl methyl ether is dissolved, and then fluorine gas is blown into the liquid to react. A semi-batch method, or a continuous method in which at least one of the above solvents is charged into a reactor and 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas are continuously charged and reacted. Can do.
[0035]
The reaction temperature may be −40 ° C. to 100 ° C., but is preferably performed in the range of −20 ° C. to 30 ° C. When the boiling point of the solvent used is lower than that of 1,1,2,2-tetrafluoroethyl methyl ether, it is necessary to provide a condenser in the reactor so that the solvent does not flow out of the reaction system. is there.
[0036]
As the reaction pressure, it is usually desirable to carry out at atmospheric pressure, but in some cases, it can be carried out under reduced pressure or slightly pressurized conditions.
[0037]
Although it does not specifically limit as reaction time, 0.5 to 30 hours are preferable.
[0038]
The charged molar ratio of 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas (F ₂ ) is preferably 1: 1 to 1:10.
[0039]
The fluorinated ether obtained by the reaction is CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₃ , CF ₃ OCF ₂ CF ₂ H, CH ₃ OCF ₂ CF ₃ , CH ₂ FOCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₂ H, CH ₂ FOCF ₂ CF ₂ H and the like.
[0040]
When performing a gas phase reaction, it is essential to dilute the fluorine gas with an inert gas such as nitrogen, helium, hydrogen fluoride, or perfluoroalkane having 4 or less carbon atoms in order to prevent reaction runaway. The ratio of fluorine gas to inert gas is preferably 0.1% to 20%. In addition, when supplying fluorine gas to a reaction system, it is preferable to mix fluorine gas with an inert gas beforehand.
[0041]
The reaction temperature can be 50 to 250 ° C., but preferably 60 to 150 ° C.
[0042]
As the reaction pressure, it is usually desirable to carry out at atmospheric pressure, but in some cases, it can be carried out under reduced pressure or slightly pressurized conditions.
[0043]
The reaction time is indicated by V / F when no catalyst is used, and is indicated by W / F when a catalyst is used, and V / F ₀ = 0.1-80 and W / F ₀ = 0.1-80 are preferable. . (V = volume of reaction zone (ml), W = catalyst weight (g), F ₀ = flow rate in standard state (ml / sec)).
[0044]
The charged molar ratio of 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas (F ₂ ) is preferably 1: 1 to 1:10.
[0045]
This reaction can be performed in the presence of a single metal such as iron, copper, zinc, nickel, tin, chromium, antimony, or in the presence of a mixture and / or alloy of two or more of these metals. is there. These metals may be added to the reaction tube as a catalyst, but a reaction tube formed of these metals can also be used. Note that if the reaction tube is made thin, heat is easily removed and the product is less decomposed.
[0046]
The fluorinated ether obtained by the reaction is CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₃ , CF ₃ OCF ₂ CF ₂ H, CH ₃ OCF ₂ CF ₃ , CH ₂ FOCF ₂ CF ₃ , CF ₂ HOCF ₂ CF ₂ H, CH ₂ FOCF ₂ CF ₂ H and the like.
[0047]
Various fluorinated ethers obtained by the above-described liquid phase reaction and gas phase reaction can be separated by an ordinary method such as vacuum distillation.
[0048]
The fluorinated ether produced by the method of the present invention can be used alone or in a mixture of two or more as a dry etching gas.
[0049]
【Example】
Hereinafter, the method of the present invention will be described specifically by way of examples.
[0050]
Example 1
In a 200 ml stainless steel container provided with a liquid phase inlet and gas outlet, 150 g of chlorotrifluoroethylene oligomer oil (Daifloil # 0 manufactured by Daikin Industries, Ltd.) and 15 g of 1,1,2,2-tetrafluoroethyl methyl ether Was charged. While stirring this solution at room temperature, nitrogen gas (57.8 ml / min) and fluorine gas (5.6 ml / min) were mixed and charged into the liquid. The reaction was always carried out at atmospheric pressure, and the discharged gas was washed with an alkaline aqueous solution and analyzed by gas chromatography.
[0051]
As a result of the analysis, the conversion of 1,1,2,2-tetrafluoroethyl methyl ether was 98%, and various fluorinated ethers were 9.27% CF ₂ HOCF ₂ CF ₃ , CF ₃ OCF ₂ CF _2. H is 2.57%, CH ₂ FOCF ₂ CF ₃ is 6.5%, CF ₂ HOCF ₂ CF ₂ H is 50.56%, and CH ₂ FOCF ₂ CF ₂ H is 31.1%. It was.
[0052]
Example 2
In a 200 ml stainless steel container provided with a liquid phase charging port and a gas discharge port, 150.0 g of perfluoropolyether oil (Demkin S-20 manufactured by Daikin Industries, Ltd.) and 1,1,2,2-tetrafluoroethylmethyl 15 g of ether was charged. While stirring this solution at 10 ° C., nitrogen gas (115.6 ml / min) and fluorine gas (11.2 ml / min) were mixed and charged into the liquid. The reaction was always carried out at atmospheric pressure, and the discharged gas was washed with an alkaline aqueous solution and analyzed by gas chromatography.
[0053]
As a result of the analysis, the conversion of 1,1,2,2-tetrafluoroethyl methyl ether is 95%, and various fluorinated ethers are 2.66% of CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF _3. but _{7.7%, CF 3 OCF 2 CF} 2 H is _{2.2%, CH 3 OCF 2 CF} 3 is _{3.44%, CH 2 FOCF 2 CF} 3 is _{8.3%, CF 2 HOCF 2 CF} 2 H Of 28.9% and CH ₂ FOCF ₂ CF ₂ H of 46.8%.
[0054]
Example 3
880 g of anhydrous hydrogen fluoride was charged into a still-liter rectification column provided with a liquid phase and gas phase charging port and a cooling condenser. While heating and refluxing hydrogen fluoride under atmospheric pressure, charging fluorine gas (57 ml / min) from the liquid phase charging port, and 1,1,2,2-tetrafluoroethyl methyl ether (37 ml / min) from the gas phase charging port. min). After continuing the reaction for 3 hours, the reaction mixture was washed with an alkaline solution, and the washing gas was analyzed by gas chromatography.
[0055]
As a result of the analysis, the conversion of 1,1,2,2-tetrafluoroethyl methyl ether was 96%, and various fluorinated ethers were 0.66% CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF _3. Is 8.2%, CF ₃ OCF ₂ CF ₂ H is 4.14%, CH ₃ OCF ₂ CF ₃ is 3%, CH ₂ FOCF ₂ CF ₃ is 7.3%, CF ₂ HOCF ₂ CF ₂ H is 30% 0.9%, CH ₂ FOCF ₂ CF ₂ H was obtained with a selectivity of 45.8%.
[0056]
Example 4
880 g of perfluorocyclobutane was charged into a still 1 L rectification column equipped with a liquid phase and gas phase charging port and a cooling condenser. While heating and refluxing perfluorocyclobutane under atmospheric pressure, supplying fluorine gas (57 ml / min) from the liquid phase charging port, and 1,1,2,2-tetrafluoroethyl methyl ether (37 ml / min) from the gas phase charging port. min). After continuing the reaction for 3 hours, the reaction mixture was washed with alkali and analyzed by gas chromatography.
[0057]
As a result of analysis, the conversion of 1,1,2,2-tetrafluoroethyl methyl ether was 98%, and various fluorinated ethers were 1.28% CF ₃ OCF ₂ CF ₃ , CF ₂ HOCF ₂ CF _3. but _{10.8%, CF 3 OCF 2 CF} 2 H is _{5.52%, CH 3 OCF 2 CF} 3 is _{5.2%, CH 2 FOCF 2 CF} 3 is _{8.5%, CF 2 HOCF 2 CF} 2 H With a selectivity of 27.5% and CH ₂ FOCF ₂ CF ₂ H of 41.2%.
[0058]
Example 5
Nickel beads (outer diameter 3 mm, total volume 56 ml) were placed in a Hastelloy C reaction tube (inner diameter 20 mm) and heated to 50 ° C. The reaction tube was reacted by flowing fluorine gas at 20 ml / min, nitrogen gas at 100 ml / min, and 1,1,2,2-tetrafluoroethyl methyl ether at 10 ml / min. Fluorine gas and nitrogen gas were mixed in advance and mixed with 1,1,2,2-tetrafluoroethyl methyl ether in a reaction tube.
[0059]
The discharged gas was washed with an alkaline aqueous solution and analyzed by gas chromatography.
[0060]
As a result of the analysis, various fluorinated ethers were 6.72% CF ₃ OCF ₂ CF ₃ , 4.08% CF ₂ HOCF ₂ CF ₃ , 2.16% CF ₃ OCF ₂ CF ₂ H, CH ₃ OCF ₂ CF ₃ is 0.71%, CH ₂ FOCF ₂ CF ₃ is 7.64%, CF ₂ HOCF ₂ CF ₂ H is 34.4%, and CH ₂ FOCF ₂ CF ₂ H is 44.29%. Obtained.
[0061]
【The invention's effect】
The present invention provides a method for producing a fluorinated ether having a high conversion rate and a small amount of by-products.

Claims (3)

  Production of fluorinated ether, wherein 1,1,2,2-tetrafluoroethyl methyl ether and fluorine gas are reacted in contact with each other in a gas phase under dilution with a gas inert to fluorine gas. Method. 2. The gas according to claim 1 , wherein the gas inert to the fluorine gas is at least one selected from the group consisting of nitrogen, helium, hydrogen fluoride, and perfluoroalkanes having 4 or less carbon atoms. Method. Fluorinated _{ether, CF 3 OCF 2 CF 3,} CF 2 HOCF 2 CF 3, CF 3 OCF 2 CF 2 H, CH 3 OCF 2 CF 3, CH 2 FOCF 2 CF 3, CF 2 HOCF 2 CF 2 H and CH the method according to claim 1 or 2, characterized in that from the group consisting of ₂ FOCF ₂ CF ₂ H is at least one selected.