JPS6112895B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to a method for producing an ester group-containing fluorocarboxylic acid fluoride, and more specifically, to a novel method for producing an ester group-containing fluorocarboxylic acid fluoride by reacting a specific fluorocycloalkenyl ether with ozone. The ester group-containing acid fluoride produced by the present invention is useful as an intermediate for the synthesis of various fluorine-containing compounds, especially various fluorine-containing compounds having an ester group at the end. for example,
Ester group-containing perfluorovinyl ether can be synthesized by reacting with hexafluorinated propylene epoxide and then thermally decomposing the reaction product. JP-A-52-83417, JP-A-52-
See Publication No. 10511, etc. In addition, it is possible to synthesize ester group-containing fluorocarboxylic acid alkali metal salts by reaction with alkali metal carbonates.
Pyrolysis of such metal salts is also possible. Unexamined Japanese Patent Publication 1972-
See Publication No. 78826, Japanese Unexamined Patent Publication No. 78827/1983, etc. Such functional perfluorovinyl ether is used as a comonomer that provides crosslinking sites for fluorine-containing polymers, or as a monomer necessary for the synthesis of fluorine-containing polymers that exhibit functionality such as ion exchange membranes for salt electrolysis. It is possible and has a wide range of uses. In addition, fluoropolyether obtained by the reaction of ester group-containing acid fluoride and hexafluorinated propylene epoxide is used as a lubricating oil, insulating oil, solvent, etc., and as a raw material for synthesis of amides, carboxylic acids, diesters, etc., and as a monomer for condensation. Possible uses are: Accordingly, the following synthesis route can be considered for the ester group-containing fluorocarboxylic acid fluoride represented by the general formula FOC-(CF ₂ ) _o -CO ₂ R, based on what has been proposed so far. That is, α, ω−
Using diiodoperfluoroalkane as a starting material, _FOC-
An example is a method in which ( _CF2 ) _o -COF or perfluorolactone is synthesized and then converted into FOC-( _CF2 ) _o - _CO2R through a monoesterification reaction with an alcohol. JP-A No. 52-23020, JP-A No. 52-23020
See Japanese Patent Application No. 39665, Japanese Patent Application No. 52-24387, Japanese Unexamined Patent Publication No. 59111-1982, Japanese Patent Application No. 113712-1983, etc. In addition, perfluorocycloalkene is oxidized with potassium permanganate in acetone or a mixed solvent of acetone-ice to give perfluorodicarboxylic acid, and this dicarboxylic acid is made into dicarboxylic acid dichloride with phosphorus pentachloride, and further By acting potassium fluoride in acetonitrile solvent
FOC-(CF ₂ ) _o -COF is obtained by monoesterification reaction with alcohol to form FOC-(CF ₂ ) _o
- A method of converting it to CO ₂ R is exemplified. As an improved process for the synthesis of FOC-( _CF2 ) _o -COF in this method, a method has also been proposed in which perfluorocycloalkene is oxidized with ozone or oxygen. See Japanese Patent Application Laid-Open No. 51-59818. In the conventional methods described above, there are difficulties in controlling the monoesterification reaction, and
Since the synthesis yield of FOC-( _CF2 ) _o -COF is also low, it is difficult to industrially produce the desired FOC-( _CF2 ) _o - _CO2R smoothly and advantageously. For example, in the method of producing FOC-(CF ₂ ) _o -COF by oxidizing perfluorocycloalkene with ozone or oxygen, the yield of the target product is as low as 15 to 25%, and the FOC obtained in this way is −(CF ₂ ) _o −COF can be monoesterified with alcohol in good yield.
It is difficult to obtain FOC−(CF ₂ ) _o −CO ₂ R. Based on the recognition of the above-mentioned problems, the present inventors aimed to provide an industrially advantageous means for producing a compound represented by the general formula FOC-( _CF2 ) _o - _CO2R .
As a result of various studies and examinations, we have come to the following interesting findings. That is, we have surprisingly discovered that a specific fluorocycloalkenyl ether and ozone react smoothly and favorably to give the desired ester group-containing fluorocarboxylic acid fluoride in good yield. By utilizing such a reaction, it is possible to omit the monoesterification step, which has been a disadvantage of the conventional method, and in combination with the above-mentioned high yield, it can become an extremely advantageous process industrially. . Furthermore, compared to methods that use fuming sulfuric acid or potassium permanganate, etc., it is extremely superior in that it eliminates the need for waste liquid treatment, does not involve dangerous reactions, and has the advantages of shortened processes and high yields. It is something that Thus, the present invention has been completed based on the above findings, and the general formula

[Formula] (However, n in the formula is an integer of 1 to 4, R is a saturated hydrocarbon group having 1 to 20 carbon atoms or a halogen-substituted hydrocarbon group, and R is one or more ethers. The general formula FOC−(CF ₂ ) _o −CO ₂ R is characterized by reacting a fluorocycloalkenyl ether represented by a bond (which may contain a bond) with ozone.
The present invention provides a novel method for producing an ester group-containing fluorocarboxylic acid fluoride represented by the formula (where n and R are the same as above). In the present invention, the raw material fluorocycloalkenyl ether has the general formula

It is a compound represented by the formula and can be synthesized by various methods and easily obtained. n is an integer of 1 to 4, and corresponds to perfluorocyclopropene, perfluorocyclobutene, perfluorocyclopentene, and perfluorocyclohexene, and usually compounds in which n is 2 to 4 are preferably employed. R is a saturated hydrocarbon group having 1 to 20 carbon atoms or a halogen-substituted saturated hydrocarbon group. Additionally, R can contain one or more ether linkages. Thus, fluorocycloalkenyl ether is a combination of perfluorocycloalkene and ROH-KOH as described, for example, in JACS, 72, 4480.
It can be synthesized by reaction with or ROH-NaOH. ROM (M is
(Li, Na, K, etc.) - polar solvents may be used;
Further, when ROH does not have solubility in KOH, a polar solvent such as dimethylformamide may be used in combination. Alcohol called ROH is easily available such as ordinary methanol and ethanol, and also CF ₂ = CF ₂ , CH ₂ = CF ₂ , CH ₂ = CH ₂ to R′I.
It may also be one synthesized using an insertion reaction of an olefin compound such as, a telomerization reaction, or the like. For example, a synthetic route such as R′I→R″CH ₂ I→R″CH ₂ OH can be adopted. As R′I, CF ₃ (CF ₂ ) _n I,
I(CF ₂ ) _n I, Cl(CF ₂ ) _n I,

[Formula] (m is 0 or an appropriate integer), and olefin compounds include C ₂ F ₄ , C ₂ H ₄ , C ₂ H ₂ F ₂ , C ₂ F ₃ Cl,
Examples include C ₂ HF ₃ , C ₂ H ₃ F, C ₃ F ₆ , etc. It can be obtained as follows. Furthermore, R″CH ₂ I→
Regarding the reaction R″CH ₂ OH, Japanese Patent Publication No. 52-8807
Publication No. 52-17007, Japanese Patent Publication No. 1700-
See Publication No. 47912, Japanese Unexamined Patent Publication No. 116406/1983, etc. In the above general formula, specific examples of R are as follows. That is, −CH ₃ , −C ₂ H ₅ , −
CH ₂ CF ₂ CHF ₂ , −CH ₂ CF ₂ CHFCF ₃ , −(CH ₂ ) _o CH ₃
(n is an integer from 2 to 19), -(CH ₂ ) ₂ (CF ₂ CF ₂ ) _o X (X is one of H, F, I, n is an integer from 1 to 5) -CH ₂ (CF ₂ CF ₂ ) _o H (n is an integer from 1 to 5)

[Formula] (n is an integer from 1 to 5) -(CH ₂ ) ₂ (CF ₂ CH ₂ ) _o CF ₃ (n is an integer from 1 to 5) -CH ₂ CF ₂ OCF (CF ₃ ) ₂ , -CH ₂ CFHOCF
(CF ₃ ) ₂ , −CH ₂ CH ₂ OCF (CF ₃ ) ₂ , −
(CH ₂ ) ₂ CFClCF ₂ OCF (CF ₃ ) ₂ , etc. The reaction in the present invention is not particularly limited and proceeds under a wide range of temperatures, but usually -100
It is preferable to conduct the reaction at a low temperature of about .degree. C. to +50.degree. C., preferably about -50.degree. C. to 0.degree. Thus, in the present invention, the reaction between the fluorocycloalkenyl ether and ozone can be carried out without the presence of a solvent, but it is also possible to carry out the reaction in an inert solvent. Examples of the solvent include trichlorotrifluoroethane, trichloromonofluoromethane, carbon tetrachloride, perfluorocyclobutane, perfluorodimethylcyclobutane, dichlorohexafluorocyclobutane, and especially saturated fluorocarbons or chlorofluorocarbons having 1 to 4 carbon atoms. . The concentration of the fluorocycloalkenyl ether in the solvent is not particularly limited, but if the concentration is too low, the space time yield will be disadvantageous, so it is usually about 0 to 10 parts by weight of the solvent per 1 part by weight of the fluorocycloalkenyl ether. may be used. Although ozone can be used in the present invention in the form of pure ozone, it is usually practical to use it in the form of ozone-containing oxygen. In this case, the ozone concentration is usually about 0.5 to 10% by volume, particularly about 1 to 5% by volume. Of course, an inert gas such as nitrogen may be included in the ozone-containing oxygen,
For example, ozone-containing air can also be used. Further, although there is no particular limitation on the amount of ozone supplied, it is desirable to take into consideration the reaction rate and the like and supply ozone so as to maintain a saturated solubility in the reaction liquid. Generally, 0.5 ozone per mole of fluorocycloalkenyl ether
A reaction molar ratio of about 100 mol, preferably 1 to 10 mol may be employed. Therefore, the supply rate of ozone-containing oxygen to the reaction solution is selected as appropriate;
Usually, oxygen with an ozone concentration of 1 to 5% by volume is used at a rate of 10 to 500 ml/min, particularly 20 to 200 ml/min, per 100 ml of reaction solution.
Approximately 1 minute is possible. Further, the reaction pressure is not particularly limited, but normal pressure is sufficient, and pressurization can be used. Under such conditions, the reaction time is 0.5~
100 hours, especially about 5 to 30 hours may be employed. In the present invention, in addition to the target FOC-(CF ₂ ) _o -CO ₂ R, a precursor of the target product is produced by the reaction of the fluorocycloalkenyl ether and ozone as described above, but after the reaction, By appropriately heating the mixture, such precursors can be converted to the desired product. Although the structure of such precursors is not necessarily clear,

[Formula] or

A possible structure is [Formula]. Therefore, the heating conditions are 20 to 80℃, preferably 40 to 60℃.
C. for about 1 to 20 hours, particularly about 4 to 10 hours. Of course, it goes without saying that such explanation does not limit the present invention in any way. Furthermore, since the reaction in the present invention is preferably carried out under substantially anhydrous conditions, the reaction materials, solvents, and other reactors used should be dehydrated by a dehydration method, drying method, etc. suitable for each before use. It is appropriate to keep it. Isolation of the desired product after completion of the reaction is carried out by a separation method such as distillation after converting the precursor into the desired product by heating. Next, embodiments of the present invention will be described in more detail, but it goes without saying that the present invention is not limited by such explanations. Example 1 A glass cylindrical reactor with an internal volume of 100 ml equipped with a dry ice condenser and a bubbler for blowing gas was charged with 10 g (0.0446 mol) of 1-ethoxy-perfluorocyclopentene and 50 ml of trichlorotrifluoroethane, and the mixture was charged. While cooling and maintaining the mixture at -25°C, oxygen gas containing 3.0% ozone by volume was blown in at 100 ml/min for 15 hours to cause a reaction, and then the reaction mixture was heated at 40°C for 8 hours.
As a result, the conversion rate of 1-ethoxy-perfluorocyclopentene was 52%, and the selectivity of 4-carboethoxy-perfluorobutyric acid fluoride was 78%. Example 2 Using a reactor similar to Example 1, a mixture of 8 g (0.046 mol) of 1-methoxy-perfluorocyclobutene and 40 ml of trichlorotrifluoroethane was cooled and maintained at -25°C while ozone was reduced to 3.0 ml. After reacting by blowing oxygen gas containing % by volume at 120 ml/min for 20 hours, the reaction mixture was heated at 40° C. for 8 hours. As a result, the conversion rate of 1-methoxy-perfluorocyclobutene was 63%, and the selectivity of 3-carbomethoxy-perfluoropropionic acid fluoride was 73%. Example 3 (a) Synthesis of 1-(2.2.3.3.3-pentafluoropropoxy)-perfluorocyclobutene In an autoclave equipped with a stirrer with an internal volume of 300 ml, 30 g of perfluorocyclobutene (0.185
mol) and 50 ml of dimethylformamide.
The reaction temperature was maintained at 0°C to 10°C, and a solution of 27.5 g (0.183 mol) of 2,2,3,3,3-pentafluoropropyl alcohol, 100 ml of dimethylformamide, and 11 g of KOH was added dropwise over 3 hours while stirring. . After standing overnight, 500 ml of water was added to separate the layers, and the lower fluorocarbon layer was distilled to obtain the desired fluorocycloalkenyl ether with a yield of 82%. (b) Reaction of 1-(2.2.3.3.3-pentafluoropropoxy)-perfluorocyclobutene and ozone Using the same reactor as in Example 1, 1-
(2,2,3,3,3-pentafluoropropoxy)-perfluorocyclobutene 10g (0.034
A mixture of 40 ml of trichlorotrifluoroethane and 40 ml of trichlorotrifluoroethane was kept cooled at -20°C while ozone was added.
15 at 80ml/min of oxygen gas containing 2.5% by volume
After reacting by blowing for a period of time, the reaction mixture is
Heat treatment was performed at 40°C for 8 hours. As a result, 1-
The conversion rate of (2,2,3,3,3-pentafluoropropoxy)-perfluorocyclobutene is
51%, and the selectivity for 3-(2.2.3.3.3-pentafluorocarbopropoxy)-perfluoropropionic acid fluoride was 71%.

Claims (1)

[Claims] 1 General formula [Formula] (wherein n is an integer of 1 to 4, R is a saturated hydrocarbon group or a halogen-substituted hydrocarbon group having 1 to 20 carbon atoms,
fluorocycloalkenyl ether represented by the general formula FOC-(CF ₂ ) _o -CO ₂ R (wherein R can contain one or more ether bonds) is reacted with ozone. middle n
and R are the same as defined above). 2. The manufacturing method according to claim 1, wherein the reaction is carried out at a reaction temperature in the range of -50°C to 0°C. 3. The manufacturing method according to claim 1, wherein the reaction is carried out in a saturated fluorocarbon having 1 to 4 carbon atoms or a chlorofluorocarbon solvent. 4. The manufacturing method according to claim 1, wherein ozone-containing oxygen having an ozone concentration of 0.5 to 10% by volume is used in the reaction. 5. The manufacturing method according to claim 1, wherein the reaction product mixture of fluorocycloalkenyl ether and ozone is further heat-treated at 20 to 80°C. 6. The manufacturing method according to claim 5, which employs heat treatment conditions of 1 to 20 hours at 20 to 80°C. 7. The manufacturing method according to claim 1, wherein 0.5 to 100 moles of ozone are used per mole of fluorocycloalkenyl ether.