JPS5974285A - Method for epoxidizing hexafluoropropylene - Google Patents

Abstract

PURPOSE:To epoxidize hexafluoropropylene without using unstable hypochlorites difficult to handle by carrying out an electrode reaction in the presence of the hexafluoropropylene, a specified chloride and a specified catalyst. CONSTITUTION:In a two-phase system consisting of org. and aqueous phases, an electrode reaction is carried out in the presence of hexafluoropropylene (a), >=1 kind of chloride (b) selected from alkali metallic chlorides and alkaline earth metallic chlorides other than Be chloride, and a quat. ammonium salt (C-1) and/or a lipophilic complexing agent (C-2) for alkali metallic cations or alkaline earth metallic cations other than Be cation as a catalyst. By the reaction the hexafluoropropylene is epoxidized. Macrocyclic polyether, macrocyclic amino-ether or polyethylene glycol is used as the lipophilic complexing agent.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for epoxidizing hexafluoropropylene (hereinafter abbreviated as HFP). More specifically, RFP is epoxidized using an electrolytic reaction to produce hexafluoropropylene oxide (hereinafter referred to as HFP).
(abbreviated as O)).

HFPO is an intermediate for producing useful fluorine-containing compounds such as hexafluoroacetone and perfluorovinyl ether, and HFPO polymers have a wide range of uses such as heat carriers and lubricating oils.

HFPO can be produced by the epoxidation reaction of RFP, but since RFP has very different chemical properties from hydrocarbon olefins such as propylene and chlorinated hydrocarbon olefins such as allyl chloride, It is difficult to epoxidize it in the same way as propylene or allyl chloride.

Up to now, several methods have been proposed for producing HFPO from HFP, but none of them can be said to be industrially advantageous. For example, U.S. Patent No. 3. ．． 3! ; RFP in a medium of alkaline hydrogen peroxide as described in &003;
How to oxidize to, or Tokusho? ! ;-//613
A typical method of oxidizing RFP to HFPO with oxygen in the presence of an inert solvent, which is described in
This is known as an FPO manufacturing method. However, with any of these methods, it is difficult to control the reaction, and the produced HF
HFPO cannot be obtained in high yield because it is difficult to suppress the decomposition of PO or because a large amount of byproducts are generated.

The present inventors have overcome the drawbacks of such conventional methods and have
As a result of intensive research to find a method to produce HFPO more easily and with higher yield than FP, we received a patent application! ;A-47
g, 3'1, special request! A-20! As shown in the specification of Japanese Patent Application No. 1, No. 1, No. 1, A'A-Z104 #7, using hypochlorite as an oxidizing agent and in the presence of a specific catalyst, an aqueous phase and an organic phase are oxidized. We have discovered a new method for carrying out the reaction in a two-phase system.

However, when producing HFPO from HFP in the two-phase reaction described above, special consideration is required for the transportation, storage, and handling of hypochlorite, which is unstable and highly corrosive.
Furthermore, used hypochlorite-containing aqueous solutions? It is also necessary to process large quantities.

As a result of further studies to find a method to solve the above-mentioned problems, the present inventors discovered a new H
We discovered a method for epoxidizing FP and completed the present invention.

That is, in the present invention, in a two-phase system of an organic phase and an aqueous phase,
a) RFP% b) At least one chloride selected from alkali metal chlorides or alkaline earth metal (excluding) chlorides, and C) (e-/)
The electrolytic reaction is carried out in the presence of at least one catalyst selected from 7411-grade ammonium salt and a lipophilic complexing agent for (eu) alkali metal cations or alkaline earth metal (excluding beryllium) cations. A novel method for epoxidizing RFP is provided.

In the method of the present invention, RFP is epoxidized by an electrode reaction in the presence of RFP, a specific chloride, and a specific catalyst, thereby eliminating the need to use unstable and difficult-to-handle hypochlorite as a raw material. Also, since the aqueous phase containing certain chlorides can be used repeatedly for a long time, the problem of wastewater treatment is also greatly reduced.

The present invention will be explained in more detail below.

Examples of the chloride used in the present invention include lithium chloride, sodium chloride, potassium chloride, rubidium chloride, cesium chloride, magnesium chloride, calcium chloride, strontium chloride, barium chloride, and the like. Among these, calcium chloride (IJ chloride) and calcium chloride are particularly suitable as the chloride used in the method of the present invention because they are available at low cost. It is also possible to use sodium chloride and calcium chloride together.

Catalysts used in the process of the invention include quaternary ammonium salts and lipophilic complexing agents for alkali metal cations or alkaline earth metal (excluding beryllium) cations; It must be able to exist stably under the reaction conditions and must have an affinity for the organic phase.

As the tertiary ammonium salt used in the method of the present invention, various tertiary ammonium salts can be used, but usually 6 to 100 q-class ammonium ions/piece.
carbon atoms are used, preferably from 70 to SO carbon atoms. Examples of 9th-class ammonium salts include, for example, tetra-n-butylammonium chloride, tri-n-octylmethylammonium chloride, The lipophilic complexing agent has the ability to complex the cation;
It may be of any type as long as it has affinity with the organic phase, but of course it must have a stable structure under the reaction conditions of the present invention.

The lipophilic complexing agent used in the method of the invention may include a very wide variety of compounds as long as they meet the above requirements. Examples of lipophilic complexing agents used in the method of the present invention are shown below, but are not limited thereto.

(1) Macrocyclic polyether; Macrocyclic polyether is commonly known as "crown ether" (for example, Pedersen,
J. Amer.

Chem. Soe. It is called ``S2Color O/7 (LProa)'' and is known to exhibit strong coordination ability for alkali metal ions and alkaline earth metal ions. Examples include Peder! I@n
According to the nomenclature, 7g-crown-6, dicyclohexyl-/1-crown-6, benzo-/S-crown-
S, dibenzo-7g-crown-6, and the like.

(1) Macrocyclic amino ether; Examples of macrocyclic amino ethers include bicyclic amino ethers and monocyclic amino ethers.

Bicyclic aminoethers are commonly referred to as "cryptands" (eg, SLehn, Tetrahsdron Lett.
, 2gg! ;, 21! g9 (/949)), and is known to exhibit extremely strong coordination ability for alkali metal ions and alkaline earth metal ions. Examples include the following:

Furthermore, examples of monocyclic aminoethers include the following.

(IIn polyethylene glycol or polyethylene glycol derivative; polyethylene glycol) Various types of polyethylene glycol can be used, but those with a degree of polymerization of 70 or more are preferable.

Examples of polyethylene glycol derivatives include n C
+sH330+CH2-CH2-0+polyethylene glycol monoalkyl ether, n C
4I(go+CH2 CH2 0-+rTf-n
Examples include polyethylene glycol dialkyl ethers such as C4Hg, and copolymers of ethylene oxide such as ethylene oxide-propylene oxide block fuborimer.

Examples of various lipophilic complexing agents that can be used in the method of the present invention have been shown above, but in addition to these, various compounds that contain a functional group that has the ability to coordinate with the metal cation can also be used. , but is not limited to the examples of complexing agents presented. Further, these lipophilic complexing agents may be supported on polymeric compounds or various insoluble carriers by various supporting methods including covalent bonding.

The amount of catalyst used in the method of the present invention is appropriately selected depending on the structure of the catalyst, type of solvent, reaction temperature, required reaction rate, etc., but is usually based on the amount of chlorine ions/gram equivalent used. , 0.0001 mol to 7θ mol, particularly preferably 0.001 mol to 1 mol. If the amount of catalyst is too small, a substantial reaction rate cannot be obtained, and if it is too large, the cost burden of the catalyst becomes large, which is economically disadvantageous.

The organic solvent for the organic phase used in the method of the present invention is an inert solvent that is substantially immiscible or poorly miscible with the aqueous phase and exists stably under the electrolytic reaction conditions. What is possible will be used. Examples include aliphatic hydrocarbons such as n-hexane and n-octane;
Examples include alicyclic hydrocarbons such as cyclohexane, aromatic hydrocarbons such as benzene, ethers such as di-n-butyl ether, perfluorocarbons such as perfluorodimethylcyclobutane, or mixed solvents thereof. It is not limited to these. When selecting an organic solvent, consider solubility in RFP and HFPO, solubility in the catalyst used in the reaction, phase separation from the aqueous phase,
An appropriate organic solvent is selected in consideration of reaction conditions such as reaction pressure and reaction temperature.

The volume ratio of the organic phase to the aqueous phase can be arbitrarily selected depending on the reaction method, reaction conditions, etc., but the organic phase is usually preferably in the range of 0.05 to 20 times the volume of the aqueous phase, and particularly preferably in the range of 0.2 to 5 times. It is.

The electrode material used in the method of the present invention is preferably one that is resistant to corrosion against chlorine and hypochlorite ions, which are electrolytic oxidation products of chlorine ions; examples thereof include:
Examples include noble metal electrodes such as platinum and palladium, or carbon electrodes.

The shape of the electrolytic cell used in the method of the present invention may be any shape as long as it is capable of electrolytic reaction and that the organic phase and aqueous phase are sufficiently mixed on the spot to cause a two-phase reaction. An electrolytic cell with the simplest structure may be, for example, a seed reactor equipped with an agitated snowmaker and a pair of electrodes.

If the temperature at which the method of the present invention is carried out is too low, the aqueous phase and organic phase will freeze, and if the temperature is too high, HFP
The yield of O decreases. Therefore, the reaction temperature is
Usually, a range from -uθ°C to gO°C is used, preferably a range from 1/,t''C to 30°C.

EXAMPLES The present invention will be explained in more detail with reference to Examples below, but the present invention is not limited by such explanations.

Example/Inner volume equipped with a pair of platinum plate electrodes with an area of 3C- on one side, parallel to each other with an interval of /sub! A real pressure bottle, a stirrer coated with fluororesin, octane yOd, tri-n-octylmethylammonium chloride 0. /
mmol s HFP aJmmol % Sodium chloride/&mmols Calcium chloride/mmols Water 10d
Fill it. Next, after cooling this solution to O''C, the stirrer inside the reaction vessel is rotated using a magnetic cooler to mix the organic phase and the aqueous phase.In this state, a voltage of +V is applied between both electrodes to cause electrolysis. The reaction was started. After 30 minutes, the amount of HFPO produced was determined by gas chromatography, and it was found that 0.023 mmol of HFPO had been produced.

Example 7 The same procedure as in Example 2 is carried out, but dicyclohexyl-7g-crown-60.2 mm is used instead of tri-n-octylmethylammonium chloride 0/mmol.
When the reaction was carried out for 20 minutes using potassium chloride/jmmol instead of sodium chloride/jmmol, 0.0//mmol of HFPO was produced. Example 3 Same operation as Example/ However, it is chlorinated) IJum/! ; Lithium chloride/ instead of mmol! r m
When the reaction was carried out for 20 minutes using mol, 0.0
/&mmol of HFPO was generated.

Example D The same procedure as in Example/ is carried out, but n-C16H is used instead of tri-n-octylmethylammonium chloride.
gO+ CH2 CH2 0 +12H O / mm
When the reaction was carried out using ol, the reaction rate was 0.0/7
mmol of HFPO was produced.

Example S Perform the same operation as Example/, but) Q − n −
Octylmethylammonium chloride O. /mmol, sodium chloride/jmm
When the reaction was carried out using magnesium chloride/jmmol instead of O. (11/4'mmol of HFPO produced 0) Patent applicant Asahi Kasei Corporation

Claims (8)

[Claims] (1) In a two-phase system of an organic phase and an aqueous phase, at least one chloride selected from a) hexafluoropropylene, b) an alkali metal chloride or an alkaline earth metal (excluding beryllium) chloride, and C) Electrolysis in the presence of at least one catalyst selected from (c/) primary ammonium salts and (C-U) lipophilic complexing agents for alkali metal cations or alkaline earth metal (excluding beryllium) cations. A method for epoxidizing hexafluoropropylene, which is characterized by carrying out a reaction. (2) The method according to claim 1, wherein IJum is used (as chloride). (3) The method according to claim 1, wherein calcium chloride is used as the chloride. (4) The method according to claim 1, wherein sodium chloride and calcium chloride are used as the chlorides. (5) The number of carbon atoms contained in the 9th class ammonium ion is from 6 to 1 per 9th class ammonium ion.
2. The method according to claim 1, using a 9th class ammonium salt within the range of 0.00. (6) The method according to claim 1, wherein the lipophilic complexing agent is a macrocyclic polyether. (7) The method according to claim 1, wherein the lipophilic complexing agent is a macrocyclic amine ether. (8) The method according to claim 1, wherein the lipophilic complexing agent is polyethylene glycol or a polyethylene glycol derivative.