JP2003212809A - New fluorine-containing ether compound and method for producing the same - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an incombustible or flame-retardant and unsymmetrical fluorine-containing ether compound having methyl group and to provide a method for simply and efficiently producing the fluorine-containing ether compound. <P>SOLUTION: This method for producing the fluorine-containing compound represented by general formula (1): CF<SB>3</SB>CF(OCH<SB>3</SB>)R (wherein R is a 1-20C aliphatic group which may have a substituent group) comprises carrying out electrolytic cross coupling reaction of a fluorine-containing compound represented by general formula (2): CF<SB>3</SB>CF(OCH<SB>3</SB>)COOM (wherein M is hydrogen or an alkali metal) with a carboxylic acid represented by general formula (3): RCOOH (wherein R is as defined above). <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a novel fluorine-containing ether compound and a method for producing the same.

[0002]

Fluorine-containing ethers are widely used as cleaning agents, heat transfer media, working fluids, reaction solvents, draining agents and the like. The method for producing such a fluorinated ether can be roughly classified into a method A for fluorinating an ether compound and a method B for synthesizing an ether compound using a compound containing a fluorine atom as a building block. The method A includes the following methods. (1) Direct fluorination of ether compounds with fluorine gas A. Sekiya et.al., Chem. Letter, 1990,609 .; RJ Ragow
et.al., J.Org.Chem., 53,78 (1988). (2) Indirect fluorination of ether compounds with metal fluorides M. Brandwood et al., J.Fluorine Chem., 5,521 (1975) (3) Electrofluorination of ether compounds T. Abe et al., J. Fluorine Chem., 15,353 (1980).

The method B includes the following methods. (4) Addition reaction of alcohol to fluorinated olefin RDChambers et.al., Adv.Fluorine Chem., 4,50 (196
5). (5) Reaction of alcohol with alkyl halide JA Young et.al., J.Am.Chem.Soc., 72,1860 (1950). (6) Reaction of fluorinated alcohol with sulfonate Patent No. 813,493 (7) Reaction of acid fluoride with sulfonate ester German Patent No. 1,294,949 (8) Electrolytic coupling T of CF ₃ C (OMe) ₂ CH ₂ COOH Kubota et.al., Chem. Lett., 1987-1990 (1988). (9) Reaction of a fluorine-containing hydroxy compound and a carbonyl compound in the presence of a catalyst JP-A-10-175899 and JP-A-11-21259 Publication Hei 11-140008 Patent Publication _{(10) CF 3 CF (OCH} 3) COOH electrolyte homocoupling Hei 11-269115 Patent Publication No.

However, it is difficult to synthesize a non-flammable or flame-retardant asymmetric fluorine-containing ether compound having a methyl group by the above-mentioned conventional techniques.

[0005]

DISCLOSURE OF THE INVENTION It is an object of the present invention to provide a non-flammable or flame-retardant asymmetric fluorine-containing ether compound having a methyl group and a method for producing the same in a simple and efficient manner. To do.

[0006]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems. That is, according to the present invention, the following fluorine-containing ether compound and a method for producing the same are provided.
(1) the following general formula _{(1) CF 3 CF (OCH} 3) R (1) ( wherein, R represents carbon atoms which may have a substituent 1 to 20
Represents an aliphatic group). (2) The following general formula (1) CF ₃ CF (OCH ₃ ) R (1) (In the formula, R has 1 to 20 carbon atoms which may have a substituent.
In the formula (2) CF ₃ CF (OCH ₃ ) COOM (2) (wherein M represents hydrogen or an alkali metal). And a carboxylic acid represented by the following general formula (3) RCOOH (3) (wherein R has the same meaning as described above) by electrolytic cross-coupling reaction. The method as described above.

[0007]

BEST MODE FOR CARRYING OUT THE INVENTION In the present invention, the fluorine-containing compound represented by the general formula (2) is used as a reaction raw material. In the above formula, M represents hydrogen or an alkali metal, and as the alkali metal, lithium, sodium, potassium,
It is rubidium, but is preferably sodium or potassium. CF ₃ CF (OCH ₃ ) COOH which is a free acid
(MTFPA) is CF ₃ CF (OCH ₃ ) COOC synthesized by adding methanol to industrially available hexafluoropropylene oxide (HFPO).
It can be easily synthesized by hydrolyzing H ₃ with an acid. In addition, its alkali metal salt (MTEPA-M)
Can be obtained by neutralizing MTFPA with an alkali metal or its hydroxide.

In the present invention, the aliphatic carboxylic acid represented by the general formula (3) is used as the other reaction raw material. In the general formula (3), R represents an aliphatic group having 1 to 20 carbon atoms. The aliphatic group includes a chain aliphatic group and a cyclic aliphatic group. The chain aliphatic group has 1 to 20 carbon atoms, preferably 1 to 12 carbon atoms, and more preferably 1 to 12 carbon atoms.
8 The cycloaliphatic group has 4 to 1 carbon atoms.
2, preferably 6-8. Further, the aliphatic group is
In addition to saturated aliphatic groups, unsaturated aliphatic groups (alkenyl,
Alkynyl).

The aliphatic group may have one or more various substituents which do not affect the coupling reaction. Such substituents include halogen atoms (chlorine, fluorine, bromine), various substituents containing a hetero atom (O, N, S, etc.) (alkoxy groups, phenoxy groups, etc.) and the like.

Specific examples of the carboxylic acid represented by the general formula (3) include the carboxylic acids shown below. Acetic acid, propionic acid, butyric acid, valeric acid, caproic acid,
Enanthic acid, caprylic acid, isobutyric acid, 2-methylbutanoic acid, 3-methylbutanoic acid, trimethylpropanoic acid, 2-
Methylpentanoic acid, 3-methylpentanoic acid, 4-isocaproic acid, 2-ethylhexanoic acid, acrylic acid, crotonic acid, isocrotonic acid, acetovinyl acid, β-ethylacrylic acid, β-pentenoic acid, acetoacrylic acid, β −
Propylacrylic acid, 3-hexenoic acid, 4-hexenoic acid, 5-hexenoic acid, 2-heptenoic acid, 3-heptenoic acid, 5-heptenoic acid, 6-heptenoic acid, 2-octenoic acid, 3-octenoic acid, 2 -Methylpropenoic acid, 2-methyl-2-butenoic acid, 2-methyl-2-pentenoic acid, 4-
Methyl-3-pentenoic acid, 2-methyl-2-hexenoic acid, 2-methyl-2-heptenoic acid, propynoic acid, tetrolic acid, 2-pentynoic acid, allyl acetic acid, 2-hexynoic acid,
2-heptic acid, 6-heptic acid, 2-octic acid, 7
-Octic acid, albrolic acid, monofluoroacetic acid, difluoroacetic acid, trifluoroacetic acid, monobromoacetic acid, dibromoacetic acid, tribromoacetic acid, monochloroacetic acid, dichloroacetic acid, trichloroacetic acid, 2-fluoropropionic acid,
3-fluoropropionic acid, 2,2-difluoropropionic acid, 3,3,3-trifluoropropionic acid, 2,
2,3,3-tetrafluoropropionic acid, pentafluoropropionic acid, 2-chloropropionic acid, 3-chloropropionic acid, 2,2-dichloropropionic acid, 3,
3,3-trichloropropionic acid, 2,2,3,3-tetrachloropropionic acid, pentachloropropionic acid,
2-bromopropionic acid, 3-bromopropionic acid,
2,2-dibromopropionic acid, 3,3,3-tribromopropionic acid, 2,2,3,3-tetrabromopropionic acid, pentabromopropionic acid, 2-fluorobutyric acid, 4-fluorobutyric acid, heptafluorobutyric acid , 2-chlorobutyric acid, 4-chlorobutyric acid, heptachlorobutyric acid, 2-bromobutyric acid, 4-bromobutyric acid, heptabromobutyric acid, 2-fluorovaleric acid, 5-fluorovaleric acid, perfluorovaleric acid, 2-chlorovaleric acid, 5-chlorovaleric acid, 2-bromovaleric acid, 5-bromovaleric acid and the like.

In the electrolytic cross-coupling reaction in the present invention, an electrolytic solvent is preferably used in the reaction. As the electrolytic solvent, a protic solvent or an aprotic solvent can be used. When a protic solvent or an aprotic solvent is used as the electrolytic solvent, it is necessary to use an appropriate supporting electrolyte.

As the protic solvent, alcohols such as methanol, ethanol and propanol can be used. The synthesis is possible even if water is mixed in these solvents. However, anhydrous alcohol is preferable because the electrolysis efficiency decreases. When the protic solvent is used as the electrolytic solvent, the supporting electrolyte is preferably an alkoxide obtained by reacting the same alcohol as the solvent and an alkali metal. Methanol (Me
When OH) is used as the electric field solvent, sodium methoxide (MeON) is used as the supporting electrolyte.
a), potassium methoxide (MeOK), lithium methoxide (MeOLi) and the like are preferable. Ethanol (Et
When OH) is used as the electrolytic solvent, sodium ethoxide (EtONa), potassium ethoxide (EtO)
K), lithium ethoxide (EtOLi) and the like are preferably used as the supporting electrolyte. Among them, MeOH /
The MeONa system is most suitable. This is because the sodium salt has higher current efficiency than other alkali metal salts.
The alkali metal of the alkoxide used for the supporting electrolyte is easily exchanged with the proton in the raw material MTFPA in the electrolytic solution to form the alkali metal salt of MTFPA.

When an aprotic solvent is used, nitriles such as acetonitrile and propionitrile, chain amides such as dimethylacetamide, 1,3-dimethyl-2-imidazolidinone and N-methyl-2-pyrrolidone are used. It is preferable to use a solvent such as a cyclic amide. When an aprotic solvent is used as an electrolytic solvent, the supporting electrolyte is preferably an alkali metal salt of MTFPA. This product can be obtained by reacting MTFPA with an alkali metal in a solvent such as alcohol to prepare an MTFPA alkali metal salt, and distilling the solvent off under reduced pressure. Examples of the alkali metal include sodium, potassium and lithium. Among them, MTFPA sodium salt, which is a salt of sodium and MTFPA, is more preferable.

The fluorine-containing ether compound represented by the general formula (1) according to the present invention can be produced by subjecting MTFPA and the carboxylic acid represented by the general formula (3) to an electrolytic cross-coupling reaction. . In the reaction, each compound is decarboxylated to give C
The reaction proceeds by generating F ₃ CF (OCH ₃ ) radicals and R radicals. In the electrolytic cross-coupling reaction in the present invention, MTFPA and the carboxylic acid represented by the general formula (3) are added to an electrolytic solvent in which a supporting electrolyte is dissolved in an electrolytic cell equipped in an electrolyzer to adjust the amount of solution. It is adjusted and subjected to constant current electrolysis with stirring. The concentration of MTFPA in the electrolytic solvent is 0.05 to
1.5 mol / l, preferably 0.1-1.0 m
ol / l. The concentration of the carboxylic acid represented by the general formula (3) is 0.2 to 2.0 mol / l, preferably 0.5 to 1.5 mmol / l. The concentration of the supporting electrolyte is suitably 0.5 to 2.0 mol / l, preferably 0.8 to 1.5 mol / l. When the concentration of the supporting electrolyte is lower than the above range, the current efficiency is remarkably lowered, and a large amount of by-products are produced on the higher side of the range. Furthermore, as the electrolysis progresses, a large amount of sodium carbonate may be deposited on the electrodes, which may prevent continuous electrolysis.

When carrying out the electrolytic cross-coupling in the present invention, the electrode in the electrolysis device is preferably an electrode having a high redox potential, and an electrode made of platinum can usually be used. Generally, the narrower the distance between the electrodes is, the better the current efficiency is. Therefore, the distance between the electrodes is preferably narrow, but if it is too narrow, there is a risk of short circuit. In this case, it is preferable to insulate with an insulator such as a mesh sheet made of polyethylene or polytetrafluoroethylene resin. Generally, the larger the electrode area,
It is self-evident that productivity will increase. Current density is 0.0
About ² to 0.1 A / cm ² , preferably 0.04 ± 0.
Setting to be 01 A / cm ² gives suitable results. If the current density is lower than this range, it takes time for the electrolysis to proceed, which is not economical. On the high current density side, generation of Joule heat is large and it becomes difficult to control the electrolytic temperature. The reaction system may be a batch system or a continuous system as desired by those skilled in the art.
In addition, the boiling point of the fluorine-containing ether compound represented by the above general formula (1) is MTFPA or M as a raw material.
Since it is lower than the boiling point of the alkali metal salt of TFPA, it can be continuously separated by reactive distillation.

In carrying out the electrolytic cross-coupling according to the present invention, the electrolysis temperature is from -5 ° C to 30 ° C, preferably 0 ° C.
To 10 ° C. In general, in the case of such one-electron oxidation reaction, the low temperature side is advantageous, but at a temperature lower than the range, the ion transfer ability is lowered, the current efficiency is lowered, and at a temperature higher than the range, byproducts are increased. To do.

[0017]

EXAMPLES Next, the present invention will be described in detail with reference to examples, but the present invention is not limited to these examples.

Reference Example To anhydrous methanol (100 g), potassium hydroxide (600
mmol) was dissolved and cooled to 0 ° C. HFPO MeO
MTFPA methyl ester (500 mmol) synthesized by H addition was slowly added dropwise. 70 ℃ after dropping
After stirring for 3 hours, the solution was concentrated under reduced pressure, and the solution was adjusted to acidic with 3N-hydrochloric acid. After this solution was extracted with diethyl ether, the diethyl ether layer was dried over anhydrous magnesium sulfate and concentrated under reduced pressure. Add 5 to this
0% by volume was added, the mixture was concentrated again under reduced pressure, and the syrupy residue was distilled under reduced pressure to obtain MTFPA with a yield of 72%.

Example 1 Synthesis of 2-methoxy-1,1,1,2,3,3-hexafluoropropane [CF ₃ CF (OCH ₃ ) CHF ₂ ] A platinum electrode (70 × 55 mm) was used for both the anode and cathode. A membrane-free beaker-type electrolysis cell (capacity: 300c) equipped with a Luggin tube, a Dimroth cooling tube, and a trap for collecting evolved gas.
c) was used. The distance between the electrodes was set to 2.0 to 3.0 mm, and a polyethylene mesh was wrapped around one of the electrodes to prevent a short circuit due to contact. As a supporting electrolyte, metallic sodium (24 mmol, 0.55
g) and MTFPA (24 mmol, 4.22 g) are dissolved in this order, and concentrated under reduced pressure to obtain a sodium salt of MTFPA (10 mol% of total substrate carboxylic acid: 24 m).
(mol) was used. Anhydrous acetonitrile was adopted as the electrolytic solvent. The electrolysis cell was cooled with ice water to remove the heat generated during electrolysis. Anhydrous acetonitrile, MTFPA (56 mm) with supporting electrolyte dissolved in the above-mentioned electrolysis cell
ol) and difluoroacetic acid (160 mmol) were added to adjust the solution amount to 240 ml, and constant current electrolysis was performed at 1.2 A (current density 31 mA / cm ² ) while stirring. The progress of the reaction was monitored by ¹⁹ F-NMR, and at the time when the amount of electricity applied was 0.8 F / mol, MTFPA was observed on the ¹⁹ F-NMR spectrum.
Electrolysis was stopped because no decrease in signal was observed. As a result, the desired cross-coupling product: 2-methoxy-1,1,1,2,3,3-hexafluoropropane was produced at a conversion of 25%. The solution after electrolysis was subjected to atmospheric pressure simple distillation to roughly separate a fraction up to 80 ° C., and this fraction was again distilled under normal pressure to separate a fraction up to 65 ° C. This fraction is 1
After washing with an aqueous solution of N-sodium hydroxide to neutralize the aqueous layer, washing with water was repeated several times. The organic layer with the water layer removed was -78
After cooling to ℃ and decanting, it was dried with sodium sulfate. This solution is rectified (bp.50-) using a rectification tube (280 x inner diameter 16 mm) in which a Helipack filler is enclosed.
51 ° C) to give the desired product, 2-methoxy-
1,1,1,2,3,3-hexafluoropropane was obtained. Spectroscopic analysis of the obtained compound was performed to confirm that the desired product was obtained. The confirmation data at this time is shown below.

[CF ₃ CF (OCH ₃ ) CHF ₂ ] ¹ H-NMR (CDCl ₃ , δppm from ™
S) 3.73 (3H, s, -CH 3) 5.88 (1H, dt, J = 2.2,52.8Hz, -
CHF ₂ ) ¹⁹ F-NMR (CDCl ₃ , δppm from C
FC-11) -79.23 (3F, t, J = 8.0H
z) -134.88 (2F, d, q, J = 52.8,
243.5 Hz) -146.16 (1F, m) MS (EI, 70 eV) [m / e] 181 (M ⁺ -1), 163 (M ⁺ -F), 131 (M ⁺ ).
_{-CHF 2), 69 (CF 3} ), 51 (CF 2) IR [cm -1] 1218 (s) --- CF, 1133 (w) ---
C-O-C

Example 2 2-methoxy-1,1,1,2-tetrafluoropropa
Synthesis Both the anode and cathode are platinum electrodes (50 x 50 mm, 80 mes
h), using a Luggin tube, Dimroth cooling tube, and generated gas trap
Non-diaphragm beaker type electrolysis cell with collecting trap
(Capacity 300 cc) was used. Distance between electrodes is 2.0 ~
It is 3.0 mm and is made of polyethylene to prevent short circuit due to contact.
The Renmesh was wrapped around one electrode. Solvent-supporting electricity
As a degrading system, 1% of total substrate carboxylic acid was added to anhydrous methanol.
0 mol% (24 mmol, 0.55 g) of metal natri
Anhydrous methanol-sodium obtained by reacting um
A methoxide type was adopted. Of the heat generated during electrolysis
Therefore, the electrolytic cell was cooled with ice water. In the above electrolytic cell
Methanol-sodium methoxide system and MTFPA (3
0 mmol, 7.04 g), acetic acid (210 mmol, 1
2.60 g) was added to adjust the solution volume to 240 ml and stirred.
4.75 A (current density 190 mA / cm while stirring) ²)
Constant current electrolysis was performed. The progress of the reaction is¹⁹By F-NMR
Traced, and at the time of 0.5 F / mol¹⁹F-NM
Decrease in MTFPA signal on R spectrum
The electrolysis was stopped because it disappeared. As a result, the desired intersection
Coupling product: 2-methoxy-1,1,1,2-
Tetrafluoropropane was produced with a conversion of 32%. Profit
The spectroscopic analysis of the
I confirmed that there was. The confirmation data at this time is as follows
Shown in.

[CF₃CF (OCH₃) CH₃]¹ H-NMR (CDCl₃, Δppm from T
MS) 1.64 (3H, d, J = 18.3Hz) 3.55 (3H, s)¹⁹ F-NMR (CDCl₃, Δppm from
CFC-11) 37.73 (1F, q, J = 18.3Hz) 77.96 (3F, s) from
int. C₆F₆ MS (EI, 70 eV) [m / e] 145 (M⁺-1), 131 (M⁺-CH₃), 77 (M⁺
-CH₃) IR [cm^-1] 1196 (s) ――― CF, 1133 (w) ――――
C-O-C

Example 3 Synthesis of 1-chloro-3-methoxy-3,4,4,4-tetrafluorobutane Example 2 was repeated except that the carboxylic acid was 3-chloropropionic acid (200 mmol, 21.70 g). Electrolytic coupling was performed under the same reaction conditions as in.
The progress of the reaction was monitored by ¹⁹ F-NMR and was 2.0 F / mo.
MTF on the ¹⁹ F-NMR spectrum at the time of the electric current of 1
Since no decrease in PA signal was observed, the confirmation data at this time is shown below. The electrolysis was stopped. As a result, the desired cross-coupling product: 1-chloro-3-
Methoxy-3,4,4,4-tetrafluoropropane was produced with a conversion of 24%. Spectroscopic analysis of the obtained compound was performed to confirm that the desired product was obtained.

[CF₃CF (OCH₃) CHCH₂CH₂C
l]¹ H-NMR (CDCl₃, Δppm from T
MS) 2.36 to 2.47 (2H, m) 3.48 (2H, dd, J = 7.06, 7.06) 3.58 (3H, s)¹⁹ F-NMR (CDCl₃, Δppm from
CFC-11) -80.10 (3F, s) -133.
04 (1F, dd, J = 18.7, 18.4 Hz) MS (EI, 70 eV) [m / e] 175 (M⁺-1), 131 (M⁺-CH₂CH₂Cl),
127, 125 (M ⁺-CF₃) IR [cm^-1] 1194 --- CF, 1070 (w) ---- CO-
C

[0025]

According to the present invention, it is possible to provide a fluorine-containing ether compound having a methyl group, which is incombustible or flame-retardant and has an asymmetric structure. In this fluorine-containing ether compound, chlorine-free hydrofluoroether (HFE) has little effect on the global environment such as ozone layer depletion and global warming, and is a solvent, a cleaning agent, a heat transfer medium, a working fluid, a reaction solvent. It can be widely used as a draining agent and the like. On the other hand, a fluorine-containing ether compound containing chlorine can be used as a reaction raw material or the like. According to the method for producing a fluorine-containing ether compound of the present invention, a non-flammable or flame-retardant asymmetric structure having a methyl group can be easily and efficiently produced.

   ─────────────────────────────────────────────────── ─── Continued front page    (71) Applicant 000002004             Showa Denko Co., Ltd.             1-13-9 Shibadaimon, Minato-ku, Tokyo (71) Applicant 000002200             Central Glass Co., Ltd.             5253 Oki Ube, Oza, Ube City, Yamaguchi Prefecture (71) Applicant 000002853             Daikin Industries, Ltd.             2-4-12 Nakazaki-nishi, Kita-ku, Osaka-shi, Osaka Prefecture             Umeda Center Building (71) Applicant 000003034             Toagosei Co., Ltd.             1-14-1 Nishishimbashi, Minato-ku, Tokyo (71) Applicant 000174851             Mitsui DuPont Fluorochemical Co., Ltd.             1-5-18 Sarugakucho, Chiyoda-ku, Tokyo (72) Inventor Toshio Kubota             4-23-10 Nishi-Narizawa Town, Hitachi City, Ibaraki Prefecture (72) Inventor Masao Komura             2-16 Yang, 3-16-1, Higashi-Narizawa Town, Hitachi City, Ibaraki Prefecture             Koso 101 (72) Inventor Ryoichi Tamai             Hongo Wakai Building 2-40-17 Hongo, Bunkyo-ku, Tokyo             6th floor Institute for Global Environmental Technology               New refrigerant, etc. Project room (72) Inventor Yasuhiro Iijima             Hongo Wakai Building 2-40-17 Hongo, Bunkyo-ku, Tokyo             6th floor Institute for Global Environmental Technology               New refrigerant, etc. Project room F-term (reference) 4H003 ED26 FA03 FA45                 4H006 AA01 AA02 AB70 AB93 AB99                       AC29 BB14 BB17 BB21 BC10                       BC30 BC40 GN38 GP01 GP20

Claims (2)

[Claims] 1. A compound represented by the following general formula (1): CF ₃ CF (OCH ₃ ) R (1) (wherein, R is a carbon number of 1 to 20 which may have a substituent).
Represents an aliphatic group). 2. A compound represented by the following general formula (1) CF ₃ CF (OCH ₃ ) R (1) (wherein R represents a carbon number of 1 to 20 which may have a substituent).
In the formula (2) CF ₃ CF (OCH ₃ ) COOM (2) (wherein M represents hydrogen or an alkali metal). And a carboxylic acid represented by the following general formula (3) RCOOH (3) (wherein R has the same meaning as described above) by electrolytic cross-coupling reaction. The method as described above.