JP4457212B2 - Method for producing fluorine-containing ether - Google Patents

Description

  The present invention relates to a method for producing a fluorine-containing ether compound.

Fluorine-containing organic compounds are widely used industrially for polymer materials, refrigerants, cleaning agents, foaming agents, pharmaceuticals, agricultural chemicals and the like. Among them, the fluorinated ether compound is expected to be used as a refrigerant substitute, a refrigerant, a cleaning agent, a foaming agent and the like.
For example, among the fluorine-containing ethers represented by the general formula (4) R ¹ CFZOR ² to be the subject of the present invention, those of R ¹ = F, R ² = CH ₃ and Z = F (CF ₃ OCH ₃ ) , And R ¹ = CF ₃ , R ² = CH ₃ , and Z = F (C ₂ F ₅ OCH ₃ ) are expected to be used as new refrigerants with little environmental impact (Non-Patent Documents) 1). R ¹ = C ₃ F ₇ , R ² = CH ₃ and Z = F (C ₄ F ₉ OCH ₃ ) are industrialized as cleaning agents.

  Conventionally, these fluorine-containing ethers include (i) perfluoro acid halides or perfluoro ketones, (ii) metal fluoride salts such as potassium fluoride, and (iii) alkylating agents such as dimethyl sulfate and methyl paratoluenesulfonate. , Diglyme, dimethylformamide, and other organic solvents (Non-Patent Document 2).

  However, since the organic solvent used in this method is volatile and generates steam, in recent years, there has been a demand for a method for producing a fluorinated ether that does not use these from the viewpoint of reducing the environmental load.

  As another method for producing a fluorine-containing ether, a method for producing a fluorine-containing ether by fluorinating a fluorine-containing unsaturated ether is known. For example, as a fluorinating agent, a higher-order metal fluoride or difluoride is used. A method of fluorination using xenon (Patent Document 1) and a method using fluorine gas (Patent Document 2) have been proposed. However, the fluorinating agent used in these methods is expensive and is volatile as described above. Since it is necessary to use an organic solvent, there has been a problem of causing environmental pollution problems.

J. Fluorine Chem., 101 (2000) 215. "ECO INDUSTRY" 1; October issue, p5, 1996) JP 2000-191578 A US Pat. No. 5,741,950

  The present invention has been made in view of the circumstances of the above prior art, and an object thereof is to provide a method capable of producing a fluorine-containing ether in an environmentally friendly and efficient manner without using a volatile organic solvent.

（式中、R³、R⁴、R⁵、R⁶、R⁷は水素または置換基を有していてもよいアルキル基をY^-は陰イオンを示す。）

（式中、R⁸、R⁹、R¹⁰、R¹¹、R¹²、R¹³は水素または置換基を有していてもよいアルキル基を示し、Y^-は陰イオンを示す。）
[４]イオン性液体が上記一般式（５）（R³ = CH₃、R⁴ = H、R⁵= CH₃またはn-C₄H₉、R⁶ = R⁷ = H、Y^- = BF₄ ^-、PF₆ ^-、CF₃SO₃ ^-、または(CF₃SO₂)₂N^-）で表される化合物であることを示す特徴とする（１）または（２）に記載の含フッ素エーテルの製造方法。 The inventor has conducted extensive research on a method for producing a fluorinated ether, found that the fluorinated ether can be synthesized in a high yield by using a non-volatile ionic liquid as a solvent, and completed the present invention. It was.
That is, according to the present invention, the following inventions are provided.
[1] In a method for producing a fluorinated ether by reacting (i) a perfluorocarboxylic acid halide or perfluoroketone, (ii) an alkylating agent and (iii) a fluorinating agent in a solvent, A method for producing a fluorinated ether, comprising using an ionic liquid.
[2] (i) Perfluorocarboxylic acid halide or perfluoroketone is represented by the following general formula (1)
R ¹ (CO) X ¹ (1)
(In the formula, R ¹ represents a fluorine atom or an optionally branched perfluoroalkyl group, and X ¹ represents a halogen atom or an optionally branched perfluoroalkyl group.)
A compound represented by
(Ii) The alkylating agent is represented by the following general formula (2)
R ² X ² (2)
(Wherein R ² represents an alkyl group which may have a substituent, and X ² represents p-CH ₃ C ₆ H ₄ SO ₃ , CH ₃ SO ₃ , CF ₃ SO ₃ , R ² OSO ₃ , I or Br)
A compound represented by
(Iii) The fluorinating agent is represented by the following general formula (3)
MF (3)
(M represents an alkali metal)
The fluorine-containing ether is represented by the following general formula (4):
R ¹ CFZOR ² (4)
(Wherein, R ^1, R ² are as .Z as above, if X ¹ is a halogen atom is fluorine, in the case of perfluoroalkyl group which may X ¹ is branched same as X ¹⁾
The method for producing a fluorinated ether according to [1] above, wherein the compound is represented by the formula:
[3] Either of the above [1] or [2], wherein the ionic liquid is an ionic liquid represented by the following general formula (5) or general formula (6) and having a melting point of 100 ° C. or lower. The manufacturing method of fluorine-containing ether of description.

(Wherein R ³ , R ⁴ , R ⁵ , R ⁶ and R ⁷ are hydrogen or an alkyl group which may have a substituent, and Y ⁻ represents an anion.)

(In the formula, R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² and R ¹³ represent hydrogen or an alkyl group which may have a substituent, and Y ⁻ represents an anion.)
[4] The ionic liquid is represented by the above general formula (5) (R ³ = CH ₃ , R ⁴ = H, R ⁵ = CH ₃ or nC ₄ H ₉ , R ⁶ = R ⁷ = H, Y ⁻ = BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , or (CF ₃ SO ₂ ) ₂ N ⁻ ), which is a compound represented by (1) or (2), Method.

  The method for producing a fluorinated ether of the present invention does not require the use of a volatile organic solvent, and therefore can significantly reduce the environmental burden compared to conventional methods using volatile solvents such as diglyme and dimethylformamide, and is desirable. It is possible to synthesize the fluorine-containing ether with a high yield. Since the solvent does not volatilize, it is easy to separate the solvent from the desired fluorine-containing ether. Moreover, the fluorine-containing ether obtained by this method is useful as a refrigerant or the like.

  The present invention relates to a process for producing a fluorinated ether by reacting (i) a perfluorocarboxylic acid halide or perfluoroketone (ii) an alkylating agent and (iii) a fluorinating agent in a solvent. An ionic liquid is used.

The synthesis reaction of the present invention can typically be represented by the following reaction formula I.
Reaction formula I

In the general formula (1), R ¹ represents fluorine or a perfluoroalkyl group which may be branched. In this case, the perfluoroalkyl group is not particularly limited, and any linear or branched perfluoroalkyl group may be used. The number of carbon atoms is usually 20 or less, preferably 10 or less, and more preferably 5 or less. Specific examples of such groups include, for example, trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, perfluoroisopropyl group, nonafluorobutyl group, perfluoroisobutyl group, perfluoro-sec-butyl group, perfluoro group. Examples thereof include alkyl groups such as -t-butyl group, undecafluoropentyl group, perfluoroisopentyl group, perfluoro-2-methylbutyl group, and perfluoro-1-methylbutyl group.

In the general formula (1), X ¹ represents a halogen atom or a perfluoroalkyl group which may be branched. Examples of the halogen atom include fluorine, chlorine, bromine and iodine. The perfluoroalkyl group which may be branched is not particularly limited, and any linear or branched perfluoroalkyl group can be used, but the carbon number is usually 20 or less, preferably 10 or less, more preferably Is 5 or less. Specifically, for example, trifluoromethyl group, pentafluoroethyl group, heptafluoropropyl group, perfluoroisopropyl group, nonafluorobutyl group, perfluoroisobutyl group, perfluoro-sec-butyl group, perfluoro-t-butyl group, Examples thereof include alkyl groups such as a decafluoropentyl group, a perfluoroisopentyl group, a perfluoro-2-methylbutyl group, and a perfluoro-1-methylbutyl group.

In the general formula (2), R ² represents an alkyl group which may have a substituent. In this case, the alkyl group is not particularly limited, and any linear or branched alkyl group may be used. The number of carbon atoms is usually 20 or less, preferably 10 or less, and more preferably 5 or less. Specifically, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, isopentyl group, 2-methylbutyl group, 1-methylbutyl group , And the like.
The substituent may be any group as long as it does not participate in the reaction. For example, a substituted or unsubstituted aryl group, nitro group, cyano group, alkoxy group, alkyl or arylsulfonyl group, fluorine, Examples include chlorine.

In the general formula (2), X ² represents p-CH ₃ C ₆ H ₄ SO ₃ , CH ₃ SO ₃ , CF ₃ SO ₃ , R ² OSO ₃ , I, or Br.

  In the general formula (3), MF represents an alkali metal fluoride, and specific examples include sodium fluoride, potassium fluoride, rubidium fluoride, and cesium fluoride, preferably potassium fluoride and potassium fluoride. More preferably, spray-dried potassium fluoride is preferred.

In the general formula (4), R ¹ is the same as R ¹ in the general formula (1), R ² is the same as R ² in the general formula (2), Z, X ¹ is a halogen atom In the case of X, it is fluorine, and when X ¹ is a perfluoroalkyl group which may be branched, it is the same as X ¹ in the general formula (1).

  In the present invention, it is necessary to use an ionic fluid as a solvent for such a synthesis reaction as described above. Here, the ionic fluid means a fluid that is a salt composed of a cation and an anion but is in a molten state near room temperature, that is, in a liquid state and does not evaporate because it has no vapor pressure.

The structure of the ionic fluid having such an action is not particularly limited, but its melting point is 100 ° C. or lower, preferably 80 ° C. or lower, more preferably 75 ° C. or lower. Examples of the ionic fluid preferably used in the present invention include compounds represented by the following general formula (5) or the following general formula (6).

In the above general formula, R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ , R ¹¹ , R ¹² , R ¹³ are hydrogen or alkyl optionally having a substituent The alkyl group in this case is not particularly limited as long as the ionic liquid has a melting point of 100 ° C. or lower, and any linear or branched alkyl group can be used. The number is usually 20 or less, preferably 10 or less, more preferably 5 or less. Specifically, for example, methyl group, ethyl group, propyl group, isopropyl group, butyl group, isobutyl group, sec-butyl group, t-butyl group, pentyl group, isopentyl group, 2-methylbutyl group, 1-methylbutyl group , And the like.
The substituent may be any group as long as it does not participate in the reaction. For example, a substituted or unsubstituted aryl group, nitro group, cyano group, alkoxy group, alkyl or arylsulfonyl group, fluorine, Examples include chlorine.

Y ⁻ represents an anion and is not particularly limited. Specifically, BF ₄ ⁻ , PF ₆ ⁻ , CF ₃ SO ₃ ⁻ , (CF ₃ SO ₂ ) ₂ N ⁻ , pC ₆ H ₄ SO ₃ ⁻ , SbF ₅ ⁻ , CH ₃ SO ₃ ⁻ , F (HF) _n ⁻ , halide ions and the like.
Among them, in the general formula (5), R ³ = CH ₃ , R ⁴ = H, R ⁵ = CH ₃ or nC ₄ H ₉ , R ⁶ = R ⁷ = H, Y ⁻ = BF ₄ ⁻ , PF ₆ ⁻ An ionic liquid such as CF ₃ SO ₃ ⁻ or (CF ₃ SO ₂ ) ₂ N ⁻ ) is preferred.
These ionic liquids are not volatile and do not generate vapor when producing a fluorinated ether, and therefore do not adversely affect the environment. Also, since the ionic liquid does not evaporate, the product is easily separated from the ionic liquid by distillation.

  Although there is no restriction | limiting in particular in the usage-amount of an ionic fluid solvent, It is 0.1 ml-20 ml normally with respect to 1 mmol of raw materials, Preferably it is 0.2 ml-10 ml, More preferably, it is 0.5 ml-5 ml.

The amount of the alkylating agent of the general formula (2) is usually equal to or more than that of the fluorinated carbonyl compound of the general formula (1), preferably 1.1 to 2 equivalents, more preferably 1. 2 to 1.5 equivalents.

  The amount of the fluorinating agent of the general formula (3) is usually equal to or greater than the fluorine-containing carbonyl compound of the general formula (1), preferably 1.2 to 3 equivalents, more preferably 1.5 to 2 equivalents.

  The reaction conditions are appropriately selected depending on the type and amount of the fluorinated carbonyl compound, the alkylating agent, the fluorinating agent, and the ionic liquid. is there.

The reaction time varies depending on the type and amount of the fluorinated carbonyl compound, alkylating agent, fluorinating agent, and ionic liquid, and the reaction temperature, but is usually in the range of 1 to 50 hours, preferably 5 to 30 hours. is there.

  EXAMPLES Next, although an Example demonstrates this invention further in detail, this invention is not limited by the following examples.

Example 1
In a reaction vessel composed of a stop valve and a stainless steel reaction tube, 308 mg (2.44 mmol) of dimethyl sulfate ((CH ₃ O) ₂ SO ₂ ), 185 mg of potassium fluoride (spray-dried product, 3.18 mmol), 1-ethyl-3 - methylimidazolium hexafluorophosphate ^{_{(EMIM + PF 6 -, EMIM}} + is the structural formula (5) R ³ is an ethyl group, R ⁵ is a methyl ^{group, R 4, R 6, R} 7 is hydrogen, Y ^- There PF ₆ ^-. things and the same with EMIM ⁺ Y having the structure ^- to show) put 1 ml, here using a vacuum line -196 ° C. with trifluoroacetic acid fluoride _{(CF 3 (CO) F)} 2 .04 mmol was added. This was heated to 70 ° C. and reacted for 20 hours. The crude product was distilled using a vacuum line to obtain 1.94 mmol (95%) of methyl pentafluoroethyl ether (C ₂ F ₅ OCH ₃ ). The product was analyzed and confirmed by IR, 1H-NMR spectrum and 19F-NMR spectrum.

Example 2
The reaction was conducted in the same manner as in Example 1 using methyl paratoluene sulfonate (p-CH ₃ C ₆ H ₄ SO ₃ CH ₃ ) instead of dimethyl sulfate, and C ₂ F ₅ OCH ₃ was obtained in a yield of 94%. Got in.

Example 3
Similar to Example 2 except that 1-ethyl-3-methylimidazolium tetrafluoroborate (EMIM ⁺ BF ₄ ⁻ ) was used instead of 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIM ⁺ PF ₆ ⁻ ). To obtain C ₂ F ₅ OCH ₃ in a yield of 93%.

Example 4
Instead of 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIM ⁺ PF ₆ ⁻ ), 1-ethyl-3-methylimidazolium bistrifluoromethylsulfonyl imidate (EMIM ⁺ (CF ₃ SO ₂ ) ₂ N ⁻ ) To give C ₂ F ₅ OCH ₃ in a yield of 84%.

Example 5
Performed using 1-ethyl-3-methylimidazolium trifluoromethanesulfonate (EMIM ⁺ CF ₃ SO ₃ ⁻ ) instead of 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIM ⁺ PF ₆ ⁻ ) Reaction was carried out in the same manner as in Example 2 to obtain C ₂ F ₅ OCH ₃ in a yield of 78%.

Example 6
Instead of 1-ethyl-3-methylimidazolium hexafluorophosphate (EMIM ⁺ PF ₆ ⁻ ), 1-butyl-3-methylimidazolium tetrafluoroborate (BMIM ⁺ BF ₄ ⁻ , BMIM ⁺ represents the structural formula (1) ) And R ⁴ is a butyl group), and the reaction was carried out in the same manner as in Example 2 to obtain C ₂ F ₅ OCH ₃ in a yield of 39%.

Example 7
Reaction was carried out in the same manner as in Example 1 using carbonyl fluoride (COF ₂ ) instead of trifluoroacetic acid fluoride (CF ₃ (CO) F) to obtain CF ₃ OCH ₃ in a yield of 91%.

Example 8
A reaction was conducted in the same manner as in Example 1 by using the pentafluoro propionic acid fluoride _{(CF 3 CF 2 (CO)} F) instead of trifluoroacetic acid fluoride _{(CF 3 (CO) F)} , CF 3 CF 2 CF 2 OCH ₃ was obtained in 42% yield.

Claims (1)

(I) a perfluorocarboxylic acid halide or perfluoroketone represented by the following general formula (1) :
^{R 1 (CO) X 1 (} 1)
(In the formula, R ¹ represents a fluorine atom or an optionally branched perfluoroalkyl group, and X ¹ represents a halogen atom or an optionally branched perfluoroalkyl group.)
(Ii) An alkylating agent represented by the following general formula (2)
R ² X ² (2)
(In the formula, R ² represents an alkyl group which may have a substituent selected from the group consisting of an aryl group, a nitro group, a cyano group, an alkoxy group, an alkyl or arylsulfonyl group, fluorine, and chlorine. , X ² represents p-CH ₃ C ₆ H ₄ SO ₃ , CH ₃ SO ₃ , CF ₃ SO ₃ , R ² OSO ₃ , I, or Br)
And (iii) fluorinating agent represented by the following general formula (3)
MF (3)
(M represents an alkali metal)
Is reacted in a solvent ,
In the method for producing a fluorinated ether represented by the following general formula (4) ,
R ¹ CFZOR ² (4)
(Same .Z wherein the R ^1, R ² is said, if X ¹ is a halogen atom is fluorine, in the case of perfluoroalkyl group which may X ¹ is branched is in the perfluoroalkyl group .)
A non-volatile ionic liquid represented by the following general formula (5) is used as a solvent.

(Wherein R ³ is CH ₃ , R ⁵ is C ₂ H ₅ or nC ₄ H ₉ , R ⁴ , R ⁶ , R ⁷ are hydrogen, Y ⁻ is BF ₄ ⁻ , PF ₆ ⁻ , CF An anion selected from ₃ SO ₃ ⁻ or (CF ₃ SO ₂ ) ₂ N ⁻ is shown.)