JPH0381239A - Production of perfluoroethyl methyl ether and its raw material - Google Patents

Abstract

PURPOSE:To obtain the subject compound on an industrial scale at a low cost by fluorinating a specific raw material compound such as ethyl trifluoromethyl ether or mono to tetrafluoroethyl trifluoromethyl ether with fluorine gas. CONSTITUTION:A perfluoroethyl methyl ether is produced by fluorinating a compound of formula (m and n are 0-2; j and k are 0-3' m+n=2; j+k=3; m+jnot equal to 0) with fluorine gas which may be diluted with a inert gas. The compound of formula is produced by reacting ethylene or trifluoroethylene or their mixture with trifluoromethyl hypofluorite of formula CF3OF without using ultraviolet radiation or catalyst. The objective compound can be produced in high yield, selectivity and efficiency with a simple procedure. The raw material for the compound can be easily produced from an inexpensive starting raw material in high yield and selectivity.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to a method for producing perfluoroethyl methyl ether and its raw material compound, and more specifically, perfluoroethyl methyl ether and a method for producing its raw material compound. The present invention relates to a method for producing fluoroethyl methyl ether (CFsOCFtCFs) and a method for producing mono- or tetrafluoroethyl trifluoromethyl ether used as a raw material compound in the method.

[Conventional technology]

Perfluoroethyl methyl ether (i.e. CPs
OCFtCFs) can be used as a refrigerant (see, e.g., U.S. Pat. No. 3,362,180, U.S. Pat.
J. Fluorine Chem, +1979 1
3+ 123; see).

Conventional methods for producing perfluoroethyl methyl ether include (1) electrolytic fluorination of ethylene glycols or 1,4-dioxanes (Berenblit);

et al, Zh, Org, Khim, 1
974.10.2031; Zh.

Pr1k1. Khim,, 1975.48.220
6; Or zh.

Pr1k1. Khim,, 19B0.53.858
) and ■ Method of reacting dioxygen difluoride (OzFz) and tetrafluoroethylene ()Iolzmar+n
, et al., Inorg, Chei+, u
He, L 972) is known.

However, this method of Φ has a problem in that the yield of perfluoroethyl methyl ether is extremely low at about 1%. In addition, in the method (2) above, the yield of perfluoroethyl methyl ether is unknown because it is not described in the paper, but in addition to the ether, as many as 7 types of by-products are produced, and the selectivity is extremely high. There are problems such as low

That is, the conventional method for synthesizing perfluoroethyl methyl ether is not practical at all from the viewpoint of yield and selectivity.

Note that a method for producing perfluoroethyl methyl ether using fluorine gas has not been known until now.

On the other hand, in the method for producing perfluoroethyl methyl ether of the present invention, tetrafluoroethyl trifluoromethyl ether (CFsOCHFCFs and CF
Conventional methods for producing aOCFzCHFz) include (a) electrolytic fluorination of β-methoxypropionic acid esters to produce CF30CHPCFs and ChOChC;
How to obtain mixtures of HFz (Berenblit, e.
tal,, Zh, Org.

Khi So, 1. LjinihiΣ, 12. 767)
, (c) A method for obtaining CFzOCHPCFs by the reaction of trifluoromethoxide difluoroethylene and hydrogen fluoride in the presence of potassium fluoride (Gubano
v+ et al,, Zh, 0bschch,
Khim, Monthly 1.34. 2802), (C)
Thermal decomposition reaction (170"C) of barfluoro-(β-methoxypropionate sodium salt)
How to obtain CHh (Gubanov, et al.,
Zh.

0bschch, Khim,, u+ 34,28
02), (d) CF3 by electrolytic decarboxylation reaction of barfluoro-(β-methoxypropionate sodium salt)
0CF ICHF! How to obtain (Berenbilt
, et al., Nov.

estf Elektrokhim, Org, 5o
edfn, Tezsiy Dokl.

Vses, 5oveshch Elektrokbi
m,, Org, 5iedfn, 8th, 19
73.31), (e) CF30CHPC by thermal decomposition reaction of Perfle 1st row (2-methoxypropyl peroxide)
How to obtain Fs (Kosendantov, et a
l,, Zh, Vses, Khis, 0-va
,, 1984 29. 113), etc. are known.

However, since these are all electrolytic reactions or thermal decomposition reactions, the yield is low (however, there is no description of the yield in the paper in (C) above), and there are many by-products, and the selectivity is extremely low. There are drawbacks such as bad.

Also, (f) Report on the reaction of CFsOF and olefins (Johri, et al., J. Org.
, Chets,, Yum48, 242), but CF
Reaction of jOF with trifluoroethylene is not shown.

A conventional method for producing CFsOCHtCHtF, which is one of the raw material compounds for perfluoroethyl methyl ether of the present invention, is as follows: (8) In the presence of hydrogen fluoride, CF30CHICIh
By the reaction of OCOF with sulfur tetrafluoride, ChOCHz
How to obtain CHzF (Aldrich, et al.
, J, Org, Chem, +1964°29,
11) and (b) A method for obtaining CF+0CHzGHzF by the reaction of ethylene and CF30F under irradiation with ultraviolet light (A11i
son, etal, J, Am, Chew, S
oc, +yu959 81.1089) are known.

The method (8) above is impractical as an industrial production method because the raw material compounds are complex and generally difficult to obtain.
There are problems such as the yield of CFffOCI (□CH,F is not very high at around 18%.On the other hand, the method (b) above uses ultraviolet rays and is disadvantageous as an industrial production method. Although there is no description of yield in this paper (b), it is generally known that radiation reactions such as ultraviolet irradiation generally have low yields and selectivities.

In any case, conventionally, ethylene and CF without ultraviolet irradiation or without catalyst! The OF reaction was unknown.

In addition, the report in (f) above also does not show any reaction between CPffOF and ethylene.Since CF and OF usually have a runaway reaction with hydrocarbon compounds, their reaction with ethylene, which is composed of carbon and hydrogen, is not indicated. It was not clear whether the reaction would proceed.

[Problem to be solved by the invention]

The present invention has been made in view of the above circumstances.

The purpose of the present invention is to solve the above-mentioned problems and to solve perfluoroethyl methyl, which has conventionally been obtained only in low yield and low selectivity, using raw materials that are relatively easy to handle or synthesize. Mono- or tetrafluoroethyl trifluoromethyl ether (CFsOCH), which can be suitably used as an ether and its starting or intermediate raw material
zCHzF 5CF30CHFCF3, ChOCFzC
An object of the present invention is to provide a method for producing Hh ) with high yield and high selectivity.

[Means to solve the problem]

As a result of intensive research to achieve the above object, the present inventors discovered that a specific raw material compound (i.e., ethyl trifluoromethyl ether, mono-tetrafluoroethyl trifluoromethyl ether) or a mixture thereof and fluorine gas. It was discovered that perfluoroethyl methyl ether can be efficiently obtained in high yield and high selectivity by a simple method of reacting, and based on this knowledge, the first invention was achieved, and further, the raw material compound As a result of intensive research on a practically advantageous production method for 2-fluoroethyl trifluoromethyl ether or CFsOCHFCh and CFs
Surprisingly, the mixture with OChCHh can be produced in high yields by the reaction of ethylene or trifluoroethylene with trifluoromethylhypofluoride (CF30F), which are very common in industry, without the use of UV light or catalysts, respectively. Moreover, they found that it can be easily obtained with high selectivity, and based on these findings, they arrived at the second invention, and by combining these, they completed the present invention.

That is, the following general formula % formula % (
) (Here, m and n in formula (I) are each 0.1
or 2, and j and k each represent 0.1.2 or 3, provided that m+n=2, j=3, and m
+j≠0. ), using fluorine gas or fluorine gas diluted with an inert gas, provides a method for producing perfluoroethyl methyl ether. The second invention is an invention relating to a method for producing a specific compound or a mixture thereof among the raw material compounds of the first invention, and is a method for producing a specific compound or a mixture thereof among the raw material compounds of the first invention, and is a method for producing a specific compound or a mixture thereof from among the raw material compounds of the first invention. The present invention provides a method for producing mono- or tetrafluoroethyl trifluoromethyl ether, which is characterized by reacting trifluoromethyl hypofluoride (ChOF).

In the present invention, the compound represented by the general formula CI) is ethyl trifluoromethyl ether CCFx0
CHzCHs), 2-fluoroethyl trifluoromethyl ether (CF, OCH, CH, F), 1-fluoroethyl trifluoromethyl ether (CF30CH
FC11,), 1,1-difluoroethyl trifluoromethyl ether (ChOCFgCH), 1,2-difluoroethyl trifluoromethyl ether (CFsOC
HFCHzF), 2,2-difluoroethyl trifluoromethyl ether (ChOCHtCHFz), 1,
1, 2-trifluoroethyl triple fluoromethyl ether (CFxOCFzCHzP), 1. 2.
2) Lifluoroethyl trifluoromethyl ether (ChOCHFCHFz), 2゜2.2-) Lifluoroethyl trifluoromethyl ether (CFsOCH
zCh), 1,1,2,2-tetrafluoroethyl trifluoromethyl ether (CF30ChCHh) and 1
, 2.2.2-tetrafluoroethyl trifluoromethyl ether (CF30CHICF!).

Among these, CFzOCHzGHz, ChOCHt
CHJ.

CF30CHICF! , CF30ChCHh , CFi
OCHFCF:+ etc. are preferred.

Incidentally, these may be used alone, or two or more may be used in combination as a mixture.

It may be subjected to the reaction as a mixture with other components within a range that does not impede the purpose of the present invention.

In addition, CJOCFzCHh and CF1OcHFcFs
and CF30CHICB! F is particularly preferred because it can be efficiently produced from inexpensive ethylene or trifluoroethylene by the second method of the present invention, that is, it can be produced by the first method and the second method of the present invention as desired. It is possible to more advantageously produce perfluoroethyl methyl ether from trifluoroethylene or ethylene and trifluoromethyl hypofluoride by a stepwise reaction or a one-step reaction method by combining them and using these as intermediate raw materials or intermediates. It is possible.

In the method of the present invention, the fluorine gas used for the reaction with the compound represented by the above general formula may be undiluted or diluted with an inert gas. Can also be used together. The inert gas is not particularly limited as long as it does not impede the object of the present invention, but argon, helium, nitrogen, etc., or a mixed gas thereof is usually preferably used. Although there is no particular restriction on the dilution rate of fluorine gas, one containing 5% by volume or more of fluorine gas is usually suitably used. When using diluted fluorine gas, fluorine gas (F2
) is preferably used, for example, in an amount of 5 to 95% by volume.

Note that these fluorine gases or inert diluted fluorine gases may be used as a mixture with other components as necessary within a range that does not impede the object of the present invention.

In the first method of the present invention, perfluoroethyl methyl ether is produced by reacting the compound represented by the above general formula with fluorine gas.

The proportion of fluorine gas (F2) used in this reaction is usually 1 equivalent or more, preferably 1 to 1 equivalent to the hydrogen atoms of the substrate (the entire compound represented by the general formula (I) used). , 5 equivalents. If this ratio is outside the above range, one of the reaction raw materials may be stoichiometrically excessive, resulting in a large amount of unreacted raw materials and a decrease in process efficiency. In particular, 1
If the reaction is carried out in less than an equivalent amount, a large amount of unreacted substrate or partially fluorinated ethyl trifluoromethyl ether may remain in the reaction mixture, which may reduce the reaction efficiency or complicate separation and purification of the desired product.

There is no particular restriction on the method of mixing fluorine gas and the substrate, and a predetermined total amount may be mixed at the same time, or may be mixed stepwise as appropriate. For substrates that react violently with fluorine gas when fluorinating compounds, it is preferable to divide the amount of fluorine gas used into the reaction system into several parts as appropriate, taking into account the intensity and progress of the reaction. This method can further suppress side reactions and further improve the yield of the desired perfluoroethyl methyl ether.

The reaction temperature is usually set within the range of -150°C to 200°C, preferably -100°C to 20"C. If the reaction temperature is too low, a sufficient reaction rate will not be obtained. On the other hand, if it is too high, side reactions such as decomposition reactions may increase and the selectivity may decrease.

Note that this reaction temperature is desirably adjusted as appropriate depending on the intensity of the reaction, the progress of the reaction, and the like.

The reaction can be carried out in various temperature modes, such as at a constant temperature. For example, a method in which the temperature is gradually raised from a low temperature as the reaction progresses and then maintained at an appropriate temperature can also be suitably employed.

In the above reaction, for example, the following formula %formula% Hydrogen fluoride is produced as in

The above reaction may be carried out in the presence or absence of a hydrogen fluoride absorbent. By using this hydrogen fluoride absorbent, it is also possible to absorb hydrogen fluoride that is generated (or contained in the raw material) and perform reactions and product separation more efficiently.

There are various types of hydrogen fluoride absorbent, but
Specific examples include sodium fluoride and potassium fluoride.

The reaction between the compound represented by general 2 and fluorine gas is as follows:
Usually, it can be carried out suitably without a catalyst, but a suitable catalyst may be used as desired.

As described above, perfluoroethyl methyl ether can be efficiently synthesized with a high yield (for example, a high yield of 85% or more) and with high selectivity. The obtained perfluoroethyl methyl ether can be separated and purified from the reaction mixture according to a conventional method and used as a product of desired purity. Further, unreacted raw materials and other components such as partially fluorinated fluoroethyl trifluoromethyl ether 1 can be used again as components for the reaction, if necessary.

Perfluoroethyl methyl ether produced as described above can be suitably used for various purposes including as a refrigerant and an inhalation anesthetic.

In a second method of the invention, ethylene or trifluoroethylene is reacted with trifluoromethylhypofluoride (CF30F) to produce 2-fluoroethyl trifluoromethyl ether or 1,2,2.2-fluoride, respectively.
- A mixture of tetrafluoroethyl trifluoromethyl ether and 1,1,2,2-tetrafluoroethyl trifluoromethyl ether is synthesized. Note that the above-mentioned mixture of mono and tetrafluoroethyl trifluoromethyl ether can be obtained by reacting a mixture of ethylene and trifluoroethylene in an arbitrary ratio with trifluoromethyl hypofluoride.

The reaction raw materials used in this reaction may be diluted with an inert gas or an inert solvent as desired, and may contain other components as long as they do not impede the purpose of the present invention. good. For example, the ethylene and/or trifluoroethylene can also be used as a mixture with other fluoroethylenes.

The reaction temperature is usually set within the range of -150"C to 200"C, preferably -100C to 20C.If the reaction temperature is too low, a sufficient reaction rate may not be obtained. On the other hand, if it is too high, side reactions such as decomposition reactions may increase and the selectivity may decrease.

Note that this reaction temperature is desirably adjusted as appropriate depending on the progress of the reaction. The reaction can be carried out in various temperature modes, such as at a constant temperature. For example, a method in which the temperature is gradually raised from a low temperature as the reaction progresses and then maintained at an appropriate temperature can also be suitably employed.

In a second method of the invention, the reaction is carried out without UV irradiation and without the use of a catalyst.

In general, even in so-called non-catalytic thermal reactions,
For example, it is known that the walls of the reaction vessel, intermediates, etc. exert a catalytic action in a broad sense, but in the method of the present invention, the term catalyst should not be interpreted in such a broad sense.

As described above, 2-fluoroethyl trifluoromethyl ether, 1.2,2゜2-tetrafluoroethyl trifluoromethyl ether, 1.1,2.2- Tetrafluoroethyl trifluoromethyl ether or a mixture thereof can be obtained in high yield (for example, with a high yield of 75% or more) and with high selectivity.

The above-obtained mono- or tetratrifluoroethyl trifluoromethyl ether or a mixture thereof can be used as it is or after being purified to a desired purity according to a conventional method as a raw material or raw material component for the reaction in the first method of the present invention. It can be suitably used in various fields of use including the following.

As described above, by combining the second method and the first method of the present invention, ethylene, trifluoroethylene, mixtures thereof, or olefins containing at least one of these, etc., which are inexpensive as industrial raw materials, can be produced. It is also possible to more advantageously produce industrially useful perfluoroethyl methyl ether from the mixed raw materials.

〔Example〕

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

Example 1 A reaction vessel made of poly(chlorotrifluoroethylene) containing sodium fluoride (10 mmol) was cooled to -194°C, and 1 mmol of CFsOCHtCFs was added to the vessel.
1 and 2.2 mmol of fluorine gas, and the reaction vessel was heated to 1.
The mixture was cooled to 11°C and gradually raised to room temperature over 20 hours. After exhausting excess fluorine gas, the resulting reaction mixture is separated and purified by changing the trap temperature.
Perfluoroethyl methyl ether is 0.94 mm
ol (yield 94%, trap temperature -155°C) was obtained. The product was identified as perfluoroethyl methyl ether for the following reasons. In the infrared absorption spectrum of the obtained product, no absorption in the C-H region was observed,
In addition, absorption of C-0 and C-F bonds (1415, 1310
~1200.1220.1170.1110C11-'
) was observed, and the measured molecular weight was 202.9, which was almost the same as perfluoroethyl methyl ether (204,0).

Example 2 A reaction was carried out in the same manner as in Example 1 except that the amount of sodium fluoride used was changed to 2 On+mol. The results are shown in Table 1.

Example 3 A reaction was carried out in the same manner as in Example 1 except that sodium fluoride was not used. The results are shown in Table 1.

Example 4 CF30CHFCF instead of ChOCHzCFx as substrate
3 and ChOChCHF! (Mixing ratio 67:33
) The reaction was carried out in the same manner as in Example 1, except that the reaction was carried out in the same manner as in Example 1. The results are shown in Table 1.

Example 5 A stainless steel reaction vessel containing sodium fluoride (10 marol) was cooled to -194°C, and CF was added to the vessel.
, OCH, CHtF 1 mtnol and fluorine gas 0.
85 mmol was charged. The reaction vessel was cooled to -111°C and heated to room temperature over 20 hours. Thereafter, the reaction vessel was cooled again to -194°C, 0°861111101 of fluorine gas was added into the vessel, and the above-mentioned operation of increasing the temperature to room temperature under the same reaction conditions as above was repeated, and the total amount of fluorine gas was 5.5°C. After charging 69 +u+ol and exhausting the excess fluorine gas, the resulting reaction mixture was separated and purified by changing the trap temperature, resulting in cpiocpzC.
F, 0.86 mIIal (yield 85%, trap temperature -153°C) was obtained.

Example 6 ChOCHzCHF instead of ChOCHzCLF as substrate
A mixture of z and CF30CHFCH,F (mixing ratio 90:1
The reaction was carried out in the same manner as in Example 5, except that the reaction mixture was changed to 0).

The results are shown in Table 1.

Example 7 CFsOCHtCh 1 mn+ol was charged into a reaction vessel cooled to -194°C without using sodium fluoride.

The reaction vessel was cooled to -70°C and 5 mmol of diluted 60% fluorine gas (Fz 3 mmol/Nz 2
mmol), and the temperature was gradually raised to room temperature over 20 hours, and then left at room temperature for 2 days. After exhausting excess fluorine gas, the reaction mixture is separated and purified by changing the trap temperature, resulting in CP! 0ChCFs (lap temperature, -153 °C) was obtained in 58% yield.

Example 8 5 mmol of ethylene was placed in a reaction vessel cooled to -194°C.
This reaction vessel containing 5 mmol of 1, CF, and OF was cooled to -153°C, and the reaction mixture was gradually heated to room temperature over 20 hours. The trap temperature was changed to separate and purify the reaction mixture, yielding CFsOCHtCHzF ( ) 4.15 mmol (yield: 89%) of lap temperature, -96°C) was obtained. The infrared absorption spectrum of the obtained product is based on known literature (J, Am, Che+w,
Soc, +1959+81,1089)
The infrared absorption spectrum matched that of CHtCHJ.

Example 9 The same procedure as Example 8 was carried out except that trifluoroethylene was used instead of ethylene as the raw material component, and CFzO
A mixture of CHFCh and CFaOCFzCHFt (mixing ratio 67:33, the mixing ratio was determined by +9p-nuclear magnetic resonance spectroscopy) was obtained with a yield of 75%.

In addition, for the following reasons, the product is CFsOCHFCFs.
and CFsOCFzCHh. The infrared absorption spectrum of the obtained product includes absorptions of C-H, C-0, and C-F bonds (3000, 1430, 1300, 1250 to 1
190.1170.1130.1110cm-') was observed, and the measured molecular weight also almost matched (analytical value 185
．． 4, calculated value 186.0). In addition, the 19p-nuclear magnetic resonance spectrum shows that CF30 at φ (CFCl, reference): 55.5.60.5.83.5 ppm, as shown below.
A chemical shift of the trifluoromethyl group of CHFCFs and ChOChC) IFs was observed, and other chemical shifts were also observed between CF30CHFCFs and CFsOChCHFs.
It supported the structure of

19p-nuclear magnetic resonance spectrum, φ (CPCI, standard)
:55, 5 (s, 3F, CFsOCFtCHh)
, 60, 5 (s, 3P, CFsOCHFCFs)
, 83, 5 (s, 3F, CF30C)lFch)
, 90, 0 (II, 2F, CFsOCFzCHF
z), 136, 0 (dd, 2F, JN-re-, =
65Hz.

Jtl-Fvic, -4Hz, CFsOCFtCH
Fz), 145, 0 (dd, IFIJH-vm-, =
64 Hz.

JM-FTTIC, = 4 Hz, CF30CHFC
Fs) [Effects of the Invention] According to the first method of the present invention, since the reaction is carried out using specific raw materials, the following effects can be achieved.

(1) Perfluoroethyl methyl ether, which has conventionally been obtained only at a low number ratio and low selectivity, can be efficiently produced at a significantly high yield and high selectivity.

(2) It is industrially advantageous because the reaction raw materials are relatively easy to obtain or the synthesis is relatively easy.

(3) Since there are few side reactions, separation and purification are extremely easy and economical.

Furthermore, according to the second method of the present invention, mono- or tetrafluoroethyl which is useful as the reaction raw material of claim 1 can be obtained from ethylene or trifluoroethylene, which is inexpensive as an industrial raw material, without using ultraviolet rays or a catalyst. Trifluoromethyl ether can be efficiently produced with high yield and high selectivity.

Furthermore, by appropriately combining the first method and the second method, perfluoroethyl methyl ether can be more advantageously produced from industrially inexpensive ethylene or trifluoroethylene.

Due to the above points, etc., the industrial value of the method of the present invention is extremely large.

Claims (1)

[Claims] 1. The following general formula CF_3OCH_mF_nCH_jF_k [I] (where m and n in the formula [I] each represent 0, 1, or 2, and j and k each represent 0, 1, 2 or 3
, where m+n=2, j+k=3, and m+
j≠0. ) A method for producing perfluoroethyl methyl ether, which comprises fluorinating a compound represented by the following formula using fluorine gas or fluorine gas diluted with an inert gas. 2. A method for producing mono- or tetrafluoroethyl trifluoromethyl ether, which comprises reacting ethylene or trifluoroethylene or a mixture thereof with trifluoromethyl hypofluorite (CF_3OF) without using ultraviolet light or a catalyst.