JP2916602B2 - Method for producing fluorine-containing ether compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to direct fluorination of an ether compound containing a chlorine atom using fluorine gas or fluorine gas diluted with an inert gas. The present invention relates to a method for replacing a chlorine atom with a fluorine atom.

[Problems to be solved by the prior art and the invention]

Fluorine-containing ethers that do not contain chlorine atoms that cause ozone layer depletion are expected as third-generation non-polluting alternatives to specified CFCs.

For this reason, development of a method for synthesizing various fluorine-containing ethers not containing chlorine has been desired. One of the methods is to effectively remove chlorine atoms in a chlorine-containing ether compound to obtain ozone. There is a demand for the development of means for producing pollution-free compounds that do not destroy layers.

On the other hand, as a method for fluorinating a chlorine atom in an ether compound, conventionally, various fluorination methods of chlorinated 2,3-dehydrofurans [N. Reeves, et al., J. CSC Chem.
ommun., 67 (1970)], a method of using anhydrous hydrogen fluoride as a fluorinating agent, a method of using antimony pentafluoride as a fluorinating agent, and a method of fluorinating with a potassium fluoride / N-methylpyrrolidone reaction system. Are known.

Other methods for fluorinating chlorine atoms in ether compounds include a method of synthesizing fluorine-containing methyl ether using antimony trifluoride as a fluorinating agent [CBMiller et al. US 2,803,665 (1957)], A method of synthesizing diethyl ether containing fluorine using antimony trifluoride as a fluorinating agent [CBMiller e
tal. US 2,803,666 (1957)].

Of these fluorination methods, the synthesis methods of,, and have a weak fluorination ability, and only some of the chlorine is partially fluorinated. Also, the method of
Perfluorinated form is obtained by fluorination of chlorine,
Requires reaction conditions as high as 200 ° C. Also,,
In the methods of,, and, the metal fluoride used for fluorination requires not more than a catalyst but an equimolar amount or more to the amount of chlorine atom to be fluorinated. It has disadvantages such as requiring metal fluoride.

On the other hand, there have been no reports of fluorinating chlorine-containing ethers using fluorine gas, and only reports of mainly chlorine-containing alkanes are known.

Therefore, a reaction in which a chlorine atom is directly replaced with a fluorine atom using a fluorine gas with respect to an ether compound containing a chlorine atom has not been reported so far.

Examples of the fluorine-containing ether compound include, for example, a general formula CF ₃ OCF _g Cl _h CF _i Cl _j ... [II] wherein g and h each represent 0, 1 or 2, and i, j represents 0, 1, 2 or 3
Is shown. Here, g + h = 2, i + j = 3, and g
+ I> 0. Are known, and such a fluorine-containing ether compound has been conventionally synthesized as follows.

The reaction of tetrafluoroethylene (CF ₂ = CF ₂ ) with chlorooxytrifluoromethane (CF ₃ OCl) gives 2-
A method for obtaining chloro-1,1,2,2-tetrafluoroethyl-trifluoromethyl ether (CF ₃ OCF ₂ CF ₂ Cl, 50% yield) (W. Maya et al. Tetrahedron Lett, 3247 (1969)) .

Reaction of tetrafluoroethylene (CF ₂ = CF ₂ ) with chloroperoxytrifluoromethane (CF ₃ OOCl) gives 2-chloro-1,1,2,2-tetrafluoroethyl-trifluoromethyl ether (CF ₃ OCF ₂ (CF ₂ Cl, 21% yield)
(DDDesMarteau et al. J. Am. Chem. Soc. 97
13 (1975)).

Reaction of chlorotrifluoroethylene (CF ₂ = CFCl) with chlorooxytrifluoromethane gives 1,2-dichloro-1,2,2-trifluoroethyl-trifluoromethyl ether (CF ₃ OCFClCF ₂ Cl, yield unknown) ) (W. Maya. Et al. Tetrahedron Lett. 3247 (1969)).

Reaction of 1,2-dichlorofluoroethylene (CFCl = CFCl) with fluorooxytrifluoromethane (CF ₃ OF) results in 1,2-dichloro-1,2,2-trifluoroethyl-trifluoromethyl ether (CF ₃ OCFClCF). ₂ Cl, yield unknown) (WSDurrel et al. J. Poly. Sci A3 406)
5 (1965)).

Chlorofluoroethylene (C ₂ F _k Cl, where k + 1 =
4) and fluorooxytrifluoromethane (CF ₃ OF),
Alternatively, a method (12-77% yield) by reaction with chlorooxytrifluoromethane (CF ₃ OCl) (DesMarteau et a
l JOrg. Chem. 48 242 (1983)).

However, these methods have problems such as low yield and low product selectivity, or use of expensive reaction reagents.

Further, as described above, there is no example of directly fluorinating chlorine atoms in a chlorine atom-containing ether compound which causes ozone layer destruction by using fluorine gas.

[Means for solving the problem]

The present inventors have conducted intensive studies to solve such conventional problems, and as a result, for chlorine-containing ether compounds,
It has been found that a fluorine-containing ether compound can be efficiently produced by directly fluorinating using fluorine gas, and the present invention has been completed based on this finding.

That is, the present invention provides a method for producing a fluorine-containing ether compound, which comprises fluorinating an ether compound having a chlorine atom at the α and / or β position using a fluorine gas or a fluorine gas diluted with an inert gas. Is provided.

As the ether compound containing a chlorine atom used in the present invention, there are various compounds. For example, a general formula CF ₃ OCH _a F _b Cl _c F _d Cl _e H _f ... [I] And c each represent 0, 1 or 2;
d, e and f represent 0, 1, 2 or 3, respectively. However,
a + b + c = 2, d + e + f = 3, and c + e>
0. ] The compound represented by these is mentioned.

Such an ether compound containing a chlorine atom can be synthesized, for example, by an addition reaction of trifluoromethyl fluorite to ethylene containing chlorine.

Specific examples of the compound represented by the general formula [I] include, for example, CF ₃ OCHCl CFClH, CF ₃ OCH ₂ CFCl ₂ , CF ₃ OCHClCFC
l ₂ , CF ₃ OCCl ₂ CFCl _{2 and the} like.

The present invention provides a method for fluorinating an ether compound having a chlorine atom at the α-position and / or β-position using a fluorine gas or a fluorine gas diluted with an inert gas as described above. And / or by replacing a chlorine atom bonded to the β-position or a chlorine atom and a hydrogen atom with a fluorine atom to produce a fluorine-containing ether compound.

It is preferable that an alkali metal fluoride coexist during the fluorination reaction. Here, even if the reaction is carried out without using an alkali metal fluoride, a fluorine-containing ether compound can be obtained. In particular, when an alkali metal fluoride such as sodium fluoride or potassium fluoride is present, the yield of the fluorinated product is reduced. The rate has improved. As an alkali metal fluoride, for example, sodium fluoride is known to absorb hydrogen fluoride, and is capable of absorbing hydrogen fluoride generated by fluorination of a hydrogen atom with fluorine gas, thereby suppressing side reactions. Seem.

Here, in the fluorination, the fluorine gas used for the reaction is not only pure fluorine gas but also 5-95 volume% by inert gas such as nitrogen gas, helium, argon, tetrafluoromethane, sulfur hexafluoride. Fluorine gas may be used.

In this case, the amount of the fluorine gas used is preferably changed as appropriate according to the intended fluorine-containing ether compound.

More specifically, in the fluorination reaction of the compound represented by the general formula [I], the following reaction can be performed by changing the amount of fluorine gas used.

a.First, when a fluorine gas is used in an amount of 1.0 to 1.1 equivalents with respect to a hydrogen atom of the compound represented by the general formula [I], only a hydrogen atom is selectively used in an ether compound having a hydrogen atom and a chlorine atom. Is possible.

b.Next, the fluorine gas is added to the compound represented by the general formula [I] in an amount of 0.7 to 1.1 with respect to the sum of the hydrogen atom and the chlorine atom.
When used in an equivalent amount, in an ether compound having chlorine atoms at the α-position and the β-position of the oxygen atom, a reaction capable of selectively replacing a hydrogen atom and a chlorine atom at the α-position with a fluorine atom is possible.

c. In addition, the fluorine gas is 0.7 to 1.1 with respect to the sum of the hydrogen atom and the chlorine atom of the compound represented by the general formula [I].
When an equivalent amount is used, although the yield is low, a reaction in which a chlorine atom at the β-position is partially replaced with a fluorine atom is possible.

d. Furthermore, when the compound represented by the general formula [I] is used in an amount of 1.5 equivalents or more with respect to the sum of the hydrogen atom and the chlorine atom, the compound represented by the general formula [I] Reaction to replace all hydrogen and chlorine atoms with fluorine
Low yields are possible (see Example 5).

In view of the above, the present invention reduces the amount of fluorine gas used,
The sum of the hydrogen atom and the chlorine atom of the compound represented by the general formula [I] can be changed according to the target compound.

In the present invention, fluorine is directly reacted with an ether compound containing a chlorine atom, and the reaction temperature in this case is generally -100 ° C to 150 ° C, preferably -50 ° C to 100 ° C.
It is. The reaction pressure is not particularly limited, and the reaction can be carried out at normal pressure.

Further, in the present invention, the reaction is carried out in the coexistence of a metal fluoride such as stannous fluoride, cobalt trifluoride, antimony trifluoride, and lead difluoride in addition to the alkali metal fluoride described above. In addition, chlorine atoms in a chlorine-containing ether compound can be efficiently fluorinated with fluorine.
Among these metal fluorides, stannous fluoride has a strong effect on the fluorination of chlorine in an ether compound containing chlorine, and is higher with less stannous fluoride than the amount of fluorination of chlorine. Because the fluorination effect was recognized,
It has been found that stannous fluoride acts as a catalyst for this chlorine fluorination (see Example 10).

In the present invention, the addition amount of the alkali metal fluoride is
With respect to 1 mmol of the compound represented by the general formula [I],
Usually, it is 1 to 100 mmol, preferably 2 to 50 mmol. Here, if the addition amount of the alkali metal fluoride is too small, the composition of the product changes, and a by-product is generated, which is not preferable. On the other hand, if the amount is too large, the reaction is undesirably slow.

The amount of the metal fluoride to be added is generally 0.01 to 10 mmol, preferably 0.05 to 2 mmol, per 1 mmol of the compound represented by the general formula [I]. Here, if the addition amount of the metal fluorides is too small, the fluorination power decreases. On the other hand, the composition of the product does not change even if the addition amount of the metal fluorides is further increased.

The coexistence of these metal fluorides in the reaction system not only dramatically improves the selectivity of the product, but also reduces the amount of fluorine gas used for hydrogen atoms of the compound represented by the general formula [I]. Even when 0.7 to 1.1 equivalents are used instead of the 1.5 equivalents or more described in d above with respect to the sum of chlorine atoms, all of the hydrogen atoms and chlorine atoms of the compound represented by the general formula (I) are replaced with fluorine atoms. Compound CF ₃ COF
It was revealed that ₂ CF ₃ was generated and the fluorination reaction was promoted.

In the present invention, the chlorine-containing ether compound can be directly fluorinated with fluorine to obtain a fluorine-containing ether compound.

When the fluorine-containing ether compound obtained here is a chlorine-containing ether compound represented by the general formula [I] as a raw material, a general formula CF ₃ OCF _g Cl _h CF _i Cl _j. In the above, g and h indicate 0, 1 or 2, and i and j indicate 0, 1, 2 or 3.
Is shown. Here, g + h = 2, i + j = 3, and g
+ I> 0. ] The fluorine-containing ether compound represented by these is obtained.

Specific examples of such a fluorine-containing ether compound include, for example, CF ₃ OCFClCF ₂ Cl, CF ₃ OCF ₂ CFCl ₂ , CF ₃ OCF ₂ CF ₂ C
_{l, CF 3 OCF 2 CF 3} , etc. _{CF 3 OCFClCFCl 2, CF 3 OCCl} 2 CF 2 Cl and the like.

The fluorine-containing ether compound synthesized in this way maintains the characteristics derived from the fluorine atoms of the chlorofluorocarbon used as chlorofluorocarbons by introducing fluorine atoms, and replaces the chlorine atoms, which cause the ozone layer destruction, with fluorine. Substitution with atoms makes it possible to reduce the number of chlorine atoms in the molecule. Therefore, these compounds are useful as intermediates for synthesizing third generation CFC substitutes.

〔Example〕

 Next, the present invention will be described in more detail with reference to examples.

Example 1 A stainless steel reaction vessel containing sodium fluoride (NaF) (10 mmol) was cooled to −194 ° C., and C was introduced into the reaction vessel.
F ₃ OCHClCFClH (1 mmol), fluorine gas and (2.2 mmol) were added. Next, the reaction vessel was cooled to −111 ° C., and gradually heated to room temperature over 20 hours. Next, put the reaction vessel in 100
After heating at 6 ° C. for 6 hours, the fluorine gas remaining in the reaction vessel was exhausted. The obtained reaction mixture was separated by changing the temperature of the trap (−60 ° C., −153 ° C., −196 ° C.).

As a result, the CF ₃ OCHClC
F ₂ Cl (75% yield) and CF ₃ OCF ₂ CF ₂ Cl (11% yield) were obtained.

The yield was calculated from the ¹⁹ F-nuclear magnetic resonance spectrum based on the amount of CF ₃ OCHClCFClH used. The results are shown in Table 1. The resulting product, CF ₃ OCFCl CF ₂ Cl, C
The chemical shift of the ¹⁹ F-nuclear magnetic resonance spectrum of F ₃ OCF ₂ CF ₂ Cl is based on literature values (WSDurrell et al, J. Poly Sci , A3 , 40
65 (1965) and W. Maya et al., Tetrahedron Lett., 23
47 (1969)].

Examples 2 to 5 In Example 1, the amount of fluorine gas used was changed to 3.3 mmol.
(Examples 2, 3) The reaction was carried out in the same manner as in Example 1 except that the amounts were changed to 4.4 mmol (Example 4) and 6.0 mmol (Example 5). In Example 3, sodium fluoride was not used. The results are shown in Table 1.

The chemical shift of the ¹⁹ F-nuclear magnetic resonance spectrum of CF ₃ OCF ₂ CF ₃ obtained in Example 5 is based on literature values [Akira Sekiya et al., Proceedings of the 14th Fluorochemistry Symposium, P-12] , p.2
8 to 29 (October 1989, Kyoto).

As is clear from the results in Table 1, the fluorination of chlorine progressed. For example, from Example 4, CF ₃ OCHClCFClH was fluorinated by fluorine gas, and the product CF ₃ OCF obtained by fluorinating α-position chlorine was obtained. ₂ CF ₂ Cl (yield 69%) was obtained. In this reaction, a product obtained by fluorinating chlorine at the β-position was not obtained, and chlorine at the α-position was selectively fluorinated.

Example 6 A stainless steel reaction vessel containing sodium fluoride (NaF) (10 mmol) was cooled to −194 ° C., and then CF ₃ CHClCFClH (1 mmol) and fluorine diluted with nitrogen were placed in the reaction vessel. gas _{(F 2 / N 2 = 3.2mmol} / 0.65mmol) was added.

Thereafter, the same operation as in Example 1 was performed. First result
It is shown in the table.

Example 7 In Example 1, instead of CF ₃ OCHClCFClH, CF ₃ OC
The same operation as in Example 1 was performed except that H ₂ CFCl ₂ was used. The results are shown in Table 1.

The chemical shift of the ¹⁹ F-nuclear magnetic resonance spectrum of CF ₃ OCF ₂ CFCl ₂ obtained as a product is based on literature values [W. Maya
et al., Tetrahedron Lett ,, 3247 (1969)].

Example 8 A reaction was carried out in the same manner as in Example 7, except that the amount of fluorine gas used was changed to 4.4 mmol. The results are shown in Table 1.

In the fluorination of CF ₃ OCH ₂ CFCl ₂ used in this example,
One of the two chlorines in the β-position was susceptible to fluorination and the product CF ₃ OCF ₂ CF ₂ Cl was obtained in a 56% yield.

Example 9 A stainless steel reaction vessel containing sodium fluoride (NaF) (10 mmol) and stannous fluoride (SnF ₂ ) (1.0 mmol) was cooled to −194 ° C., and then placed in the reaction vessel. , C
F ₃ OCHClCFClH (1 mmol) and fluorine gas (3.3 mmol) were added.

Thereafter, the same operation as in Example 1 was performed, and as products, CF ₃ OCFClCF ₂ Cl (yield 9%), CF ₃ OCF ₂ CF ₂ Cl
(54% _{yield), CF 3 OCF 2 CF 3} (9% yield). The results are shown in Table 1.

Examples 10 to 12 In Example 9, the amount of stannous fluoride (SnF ₂ ) was set to 0.
50 mmol (Example 10), 0.35 mmol (Example 11), 0.10 mmol
The reaction was carried out in the same manner as in Example 9 except that (Example 12) was used. The results are shown in Table 1.

As is clear from Table 1, by using stannous fluoride together with sodium fluoride as in Example 11,
The yield of the product CF ₃ OCF ₂ CF ₂ Cl was improved, for example, as compared with Example 4, and a perfluoro compound in which β-position chlorine was fluorinated was obtained. It turns out that it is effective in the fluorination reaction.

In Example 13-14 Example 11, CF ₃ OCH ₂ instead of CF ₃ OCHClCFClH
The same operation as in Example 11 was performed except that CFCl ₂ (Example 13) and CF ₃ OCHClCFCl ₂ (Example 14) were used. First result
It is shown in the table.

Example 15 In Example 11, instead of CF ₃ OCHCl CFClH, CF ₃ OC
The same operation as in Example 11 was performed except that Cl _{2 and} CFCl ₂ were used and a predetermined amount of fluorine gas was used. The results are shown in Table 1.

Examples 16 to 18 In Example 9, antimony trifluoride (Example 16), cobalt trifluoride (Example 17), and lead difluoride (Example) were used in place of stannous fluoride (SnF ₂ ). The reaction was carried out in the same manner as in Example 9 except that Example 18) was used. The results are shown in Table 1.

[Effects of the Invention] According to the method of the present invention, a fluorine-containing ether compound can be produced in good yield by directly fluorinating and inactivating a chlorine-containing ether compound, and particularly, an alkyl such as sodium fluoride. By fluorinating in the presence of a metal fluoride and further a metal fluoride such as stannous fluoride, the yield and product selectivity can be further improved.

According to the method of the present invention, a fluorine-containing ether compound which has a low content of chlorine atoms and hydrogen atoms causing destruction of the ozone layer and is also useful as an anesthetic absorbing agent and a refrigerant,
It can be manufactured efficiently, economically and safely.
Therefore, the present invention is extremely useful industrially.

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁶ Identification code FI C07B 61/00 300 C07B 61/00 300

Claims (6)

(57) [Claims] 1. A method for producing a fluorine-containing ether compound, comprising fluorinating an ether compound having a chlorine atom at the α-position and / or β-position using a fluorine gas or a fluorine gas diluted with an inert gas. Method. 2. An ether compound having a chlorine atom at the α-position and / or β-position, which is selected from the group consisting of sodium fluoride and potassium fluoride, using a fluorine gas diluted with a fluorine gas or an inert gas. A method for producing a fluorine-containing ether compound, comprising fluorinating in the presence of an alkali metal fluoride. 3. Use of a fluorine gas obtained by diluting an ether compound having a chlorine atom at the α-position and / or β-position with a fluorine gas or an inert gas, and using stannous fluoride, cobalt trifluoride, or trifluoride. Characterized by fluorinating in the presence of one or more metal fluorides selected from the group consisting of antimony and lead difluoride,
A method for producing a fluorine-containing ether compound. 4. A compound of the general formula CF ₃ OCH _a F _b Cl _c F _d Cl _e H _f .. [I] wherein a, b and c each represent 0, 1 or 2;
d, e and f represent 0, 1, 2 or 3, respectively. However, a + b + c = 2, d + e + f = 3, and c +
e> 0. Wherein the compound represented by the general formula CF ₃ OCF _g Cl _h CF _i Cl _j is expressed by fluorinating using a fluorine gas or a fluorine gas diluted with an inert gas. In the above, g and h indicate 0, 1 or 2, and i and j indicate 0, 1, 2 or 3.
Is shown. Here, g + h = 2, i + j = 3, and g
+ I> 0. ] The manufacturing method of the fluorine-containing ether compound represented by these. 5. A compound of the general formula CF ₃ OCH _a F _b Cl _c F _d Cl _e H _f (I) wherein a, b and c each represent 0, 1 or 2;
d, e and f represent 0, 1, 2 or 3, respectively. However, a + b + c = 2, d + e + f = 3, and c +
e> 0. Fluorinating the compound represented by the formula (1) using fluorine gas or a fluorine gas diluted with an inert gas, and in the presence of an alkali metal fluoride selected from the group consisting of sodium fluoride and potassium fluoride. Characteristic, general formula CF ₃ OCF _g Cl _h CF _i Cl _j ... [II] [wherein, g and h represent 0, 1 or 2, and i, j represent 0, 1, 2 or 3
Is shown. Here, g + h = 2, i + j = 3, and g
+ I> 0. ] The manufacturing method of the fluorine-containing ether compound represented by these. 6. A compound of the general formula: CF ₃ OCH _a F _b Cl _c F _d Cl _e H _f (I) wherein a, b and c each represent 0, 1 or 2;
d, e and f represent 0, 1, 2 or 3, respectively. However, a + b + c = 2, d + e + f = 3, and c +
e> 0. The compound represented by the above, using a fluorine gas or a fluorine gas diluted with an inert gas, and selected from the group consisting of stannous fluoride, cobalt trifluoride, antimony trifluoride and lead difluoride General formula CF ₃ OCF _g Cl _h CF _i Cl _j …… [II] wherein fluorination is performed in the presence of one or more metal fluorides. 1 or 2, i, j is 0,1,2 or 3
Is shown. Here, g + h = 2, i + j = 3, and g
+ I> 0. ] The manufacturing method of the fluorine-containing ether compound represented by these.