JPH03153677A - Production of hexafluoropropylene oxide - Google Patents

Abstract

PURPOSE:To economically obtain the subject compound by subjecting hexafluoropropylene to oxidative reaction in a two-phase system using a quaternary onium cationic salt catalyst, then activating the aforementioned catalyst according to a specific method and reutilizing the resultant catalyst. CONSTITUTION:Hexafluoropropylene is initially oxidized in a two-phase system of an organic phase, sparingly miscible in water and containing a catalyst composed of a salt of a quaternary onium cation expressed by the formula [A is N or P; R1 to R4 are (substituted) hydrocarbon, provided that the total number of carbon atoms in the R1 to R4 is >=8 per onium ion] and an aqueous phase containing hypochlorous acid which is an oxidizing agent. The organic phase containing the quaternary onium slat of the fluorine-containing carboxylic acid with deteriorated catalyst activity formed in the aforementioned reaction is then brought into contact with an aqueous phase containing thiocyanate ions and the formed organic phase containing the produced quaternary onium thiocyanate is subsequently brought into contact with an aqueous solution containing a water-soluble oxidizing agent to decompose the thiocyanate ions. The aforementioned organic phase is then reutilized in synthetic reaction for the hexafluoropropylene oxide.

Description

Detailed Description of the Invention (Industrial Application Field) The present invention relates to a method for producing hexafluoropropylene oxide, and more specifically, it relates to a method for producing hexafluoropropylene oxide using a specific quaternary onium salt as a phase transfer catalyst. The present invention relates to a method for producing hexafluoropropylene oxide, which incorporates a quaternary onium salt activation treatment step.

(Prior art) Hexafluoropropylene oxide (hereinafter referred to as "HF P
(abbreviated as "O") is an industrially extremely important substance that serves as a raw material for various highly functional fluorine-based materials such as perfluorolubricants, perfluoroelastomers, and perfluoroion exchange resins.

Until now, no economical method for producing HFPO was known, but Japanese Patent Application Laid-open Nos. 183773-1982, 105978-1980, and 13408-1980
As shown in Publication No. 6, etc., an organic phase that is poorly miscible with water and contains various phase transfer catalysts such as quaternary ammonium salts and quaternary phosphonium salts, and hypochlorous acid as an oxidizing agent. When hexafluoropropylene (hereinafter abbreviated as "RFP") is reacted in a two-phase system of an aqueous phase containing a salt,
It has been found by the inventors that HFPO can be obtained in high yield under mild conditions.

Next, the present inventors used hypochlorite as an oxidizing agent to achieve an industrially advantageous method for producing HFP from HFP using a phase transfer catalytic reaction method.
In order to establish a method for producing FPO, we conducted a more detailed study and found that the above-mentioned compound (
The quaternary onium cation (hereinafter abbreviated as 0) in 1).

) When using a hydrophobic quaternary ammonium salt or a hydrophobic quaternary phosphonium salt, if the quaternary onium salt is used repeatedly in the reaction, its catalytic activity gradually decreases, and if it is left as is, it will react for a long time. It has been found that it is not possible to obtain constant RFP conversion over time.

Therefore, when carrying out the HFPO synthesis reaction repeatedly, in order to obtain a certain reaction result, it is necessary to
Either reactivate the class onium salt catalyst in some way, or
Alternatively, it is necessary to adopt a method of replacing part or all of the quaternary onium salt catalyst whose activity has decreased with a new catalyst, or furthermore, a method of adding a new catalyst to the quaternary onium salt catalyst whose activity has decreased. be.

However, the method of maintaining activity using new quaternary onium salt catalysts results in high catalyst costs.

In addition, when replacing a part of a catalyst whose activity has decreased with a new catalyst or adding a new catalyst, it is difficult to control the reaction conditions in order to obtain a certain reaction result.
The operation is also complicated, which is economically disadvantageous.

Therefore, the quaternary onium salt can be repeatedly used as a phase transfer catalyst in HFPO synthesis reaction to produce an economical HFP.
In order to establish an O production process, it is necessary to develop a method for regenerating a catalyst whose activity has decreased.

Therefore, the present inventors first investigated the cause of the decrease in activity of the quaternary onylam salt catalyst.

As a result, in the quaternary onium salt catalyst with decreased activity, the fluorine-containing carboxylate anion (16
A characteristic absorption band is shown at 95 cm-'. ] was confirmed to exist.

In addition, “F-N” of the quaternary onium salt catalyst with decreased activity
From the MR spectrum, the fluorine-containing carboxylate anion is mainly composed of multiple C3 polyfluorocarboxylate anions [CF3CFXCO□O(X=F
, cp, H).

), CF, C0,9, and ChCF
It was found that there was more XCO7O than CF:1CO10.

[Hereinafter, the fluorine-containing carboxylate anion will be referred to as “R
f, Co□.) CF3CFzCO□○ is thought to be derived from CF, CF2C0F, produced by isomerization of HFPO.On the other hand, the detailed production mechanism of ChCO2G and other RflCO20 is unknown. , HFP or HFPO
It is thought to have been generated by the decomposition of

The present inventors have discovered that Rf, CO□■0 by ion exchange reaction.
The JA phase containing large amounts of phase transfer catalytic activity from It was found that almost no ion exchange reaction occurred, and that Rf, CO, and ○Q■ formed very stable ion bears.

From the above results, although the reason for the low phase transfer catalytic activity of the quaternary onium salt containing Rf+GO2oQ'3 has not been clearly confirmed, it is probably RfCO20
Since Q■ forms a stable ion bear, Rf,
Ion exchange between CO2■ and hypochlorite ion (OClO) becomes difficult to occur, and as a result, Q■OCl○ is difficult to form, so in Rf+COz■Q■, OClO is used as a medium to move from the aqueous phase to the organic phase. This seems to be because the function of the phase transfer catalyst is not fully expressed.

Therefore, in the HFPO synthesis reaction, in order to regenerate the quaternary onium salt mainly composed of Rf + COz OQ■ whose activity has decreased, it is necessary to use some method to regenerate Rf, COz
It is considered that ○Q■ can be converted into a quaternary onium salt that can be easily ion-exchanged.

However, conventionally, compared to quaternary onium salts that form highly stable ion bears, q+E)ocj20 and Q■OH○
Alternatively, no economically superior method of converting into a quaternary onium salt such as Q(E)ISO,O, which is easily ion-exchangeable, has been known.

As a conventional method for converting quaternary onium salts forming highly stable ion bears, for example, (CH: +0)
BrFndst using xs02
r; II+) method (C, M, 5 tarks and
C. Liotta, “PhaseTransfer.
Catalysis', Academic Pre
ss, Page 74] is known, but it not only has the problems of complicated operation and the use of toxic (CH:10) zsO□, but also has little effect on the activation of Rf + COz OQ O. was not recognized.

(Problems to be Solved by the Invention) As shown above, the quaternary onium salt is
In order to repeatedly use HFPO as a phase transfer catalyst in synthetic reactions and to establish an economical HFPO production process, it is necessary to develop a method for regenerating the catalyst whose activity has decreased, but an appropriate method has not yet been found. There wasn't.

(Means for Solving the Problems) Therefore, the present inventors have intensively investigated a method for activating a quaternary onium salt mainly composed of Rf, Co□OQO, which has a reduced HFPO synthesis reaction activity, and found that thiocyanine We have discovered a method that utilizes the properties of acid ions.

First, as a result of intensive studies on various ion exchange methods, the present inventors surprisingly found that when an organic phase containing Rf and COZ○Q9 was brought into contact with an aqueous phase containing thiocyanate ion SCN■, the present invention It was found that Rf, C(h(EIQ■) used in Rr, co, and O easily undergo ion exchange with SCN O.

As a result, a quaternary onium thiocyanate salt is formed in the organic phase, and Rf and Co□·D are transferred to the aqueous phase, so that RflCO□O can be easily recovered from the aqueous phase.

Note that the quaternary onium thiocyanate salt produced in the organic phase formed a very stable ion pair, and it was difficult to exchange it with various anions in the aqueous phase as it was. Therefore, the present inventors investigated quaternary thousocyanic acid in the organic phase.
We conducted extensive research to find a method for converting quaternary onium salts into active quaternary onium salts that can be easily ion-exchanged, and found that when an organic phase containing a quaternary onium salt of thiocyanate is brought into contact with an aqueous phase containing a water-soluble oxidizing agent, We have completed the present invention by discovering that SCN (SCN) decomposes easily under mild conditions, resulting in the formation of an active quaternary onium salt in the organic phase that exhibits high catalytic activity in the HFPO synthesis reaction. reached.

That is, the present invention provides -generation (+3 RIRzRJaA 9(1) (where A represents an N or P atom, R+, RzR
3 and R4 represent a substituted or unsubstituted hydrocarbon group. The total number of carbons in R+, Rz, Rz and R4 is at least 8 per onium ion.

R,, R,, R3 and R4 may be linked to each other to form a heterocycle, or R+, RZ, R3 or R4 may contain another onium ion. )
A two-phase system consisting of a water-immiscible organic phase containing a catalyst consisting of a salt of a quaternary onium cation represented by In a method for producing fluoropropylene oxide, (1) an organic phase containing a fluorine-containing carboxylic acid quaternary onium salt with reduced catalytic activity produced by a hexafluoropropylene oxide synthesis reaction is contacted with an aqueous phase containing thiocyanate ions. 4th thiocyanate
(ii) the organic phase containing the quaternary onium thiocyanate salt is then contacted with an aqueous solution containing a water-soluble oxidizing agent to decompose the thiocyanate ions; (iii) The present invention relates to a method for producing hexafluoropropylene oxide, which includes a quaternary onium salt activation treatment step, characterized in that the obtained organic phase is used again as an organic phase in a hexafluoropropylene oxide synthesis reaction.

As described above, in order to carry out the activation treatment of the quaternary onium salt of the present invention, it is sufficient to carry out the two-phase reaction of the organic phase and the aqueous phase in a dish, and the treatment method of the present invention The generated organic phase containing the active quaternary onium salt can be used repeatedly in the 35 t+ F PO synthesis reaction as it is.

Furthermore, according to the method of the present invention, Rf and CO□/U can be easily recovered from the aqueous phase obtained in the first stage treatment. Therefore, by employing the method of the present invention, it becomes possible to regenerate the catalyst and simultaneously recover the fluorine-containing carboxylic acid produced as a by-product in the HFPO synthesis reaction.

The present HF PO production method will be explained in more detail below.

The organic phase, aqueous phase, and quaternary onium salt used in the HF P 0 synthesis step of the present HF P 0 production method are described in JP-A-57-183773 and JP-A-58-105978.
The information shown in the publication, etc. is used as is.

For example, as the quaternary onium cation represented by the general formula [I] in the quaternary onium salt catalyst, R,, R2, L
A hydrophobic quaternary onium cation containing a hydrocarbon group and R4 is used.

The type and length of this hydrocarbon group are appropriately selected depending on the solvent used, the purpose of use, etc. Examples of the type of hydrocarbon group include an alkyl group, an alkenyl group, a cycloalkyl group, a cycloalkenyl group, an aryl group, an aralkyl group, an alkenylaryl group, and particularly preferably an alkyl group, an aralkyl group, and an alkenyl aryl group. Aralkyl groups and the like are used.

In addition, the lengths of the hydrocarbon groups are R1, R2, R3 and R
The total number of carbon atoms contained in 4 is at least 8 per onium ion, usually in the range of 8 to 70, preferably in the range of 10 to 50, particularly preferably 12 to 50. The range is 40. The above hydrocarbon group may be substituted with a substituent that is stable under the reaction conditions of the present invention.

The inert substituents that can be substituted on the above hydrocarbon groups are limited depending on the reaction conditions, but halogens, acyl groups, ether groups, ester groups, nitrile groups, alkoxyl groups, etc. are usually used. .

R+, R2, R: l and R4 may be linked to each other to form a heterocycle, or R,, R2, R3 or R4 may contain another onium ion.

- Examples of hydrophobic quaternary onium cations represented by format (1) include, for example, tetra-n-propyla>
'monium ion, tetra-n-butylammonium ion, tri-n-octylmethylan, monium ion, tetra-n-octylammonium ion, tetra-
n-decylammonium ion, cetyltrimethylammonium ion, trirhodecylmethylammonium ion, benzyltrimethylammonium ion, benzyltriethylammonium ion, cetylbenzyldimethylammonium ion, cetylpyridinium ion, n-dodecylpyridinium ion, phenyltrimethylammonium ion, phenyl Quaternary ammonium ions such as triethylammonium ion, N-benzylpicolinium ion, pentamethonium ion, hexamethonium ion; or tetra-n-butylphosphonium ion, tri-n-octylethylphosphonium ion, tri-rooctylmethylphosphonium ion, cetyltriethylphosphonium ion, cetyltri n-butylphosphonium ion, n-butyltriphenylphosphonium ion) n-amyltriphenylphosphonium ion, n-hexyltriphenylphosphonium ion, n-hebutyltriphenylphosphonium ion,
Examples include quaternary phosphonium ions such as methyltriphenylphosphonium ion, benzyltriphenylphosphonium ion, and tetraphenylphosphonium ion.

Furthermore, various types of anions can be used as anions in the quaternary onium salt used in the first HF P 0 synthesis step in the present invention, and halogen ions such as chloride ions and bromide ions are usually used. , hydroxide ion, sulfate ion, hydrogen sulfate ion, etc., but are not limited thereto.

The sparingly water-miscible organic phase used in the present invention is of the form [
It contains a salt of the quaternary onium cation shown in [1] and forms a phase different from the aqueous phase, and usually consists of a quaternary onium salt and an organic solvent that is poorly miscible with water. ,
Depending on the case, the main component may be a liquid quaternary onium salt, or the organic phase may consist of two or more types of phases that are poorly miscible with water. .

Examples of poorly water-miscible organic solvents for the organic phase used in the method of the invention include, for example, aliphatic hydrocarbons such as n-hexane, n-octane, n-decane; cyclohexane, methylcyclohexane, Alicyclic hydrocarbons such as decalin; aromatic hydrocarbons such as benzene, toluene, and xylene; ethers such as diisopropyl ether and di-n-butyl ether; methylene chloride, chloroform, carbon tetrachloride, I, 2-dichloroethane , chlorinated hydrocarbons such as chlorobenzene; 1,2-dichloro-1,L2,2-
Tetrafluoroethane, fluorotrichloromethane, 1
．． 1.2-1-cyclo1.2.2-Trifluoroethane, Ll, hydrocarbons substituted with chlorine atoms and fluorine atoms such as 2.2-tetrachloro-1,2-difluoroethane; perfluorocyclobutane, Perfluorodimethylcyclobutane, perfluorohexane, perfluorooctane, perfluorodecane, 1,3 di(trifluoromethyl)benzene, hexafluorobenzene, 2
H-tetradecafluoro-5-(trifluoromethyl)
Examples include, but are not limited to, perfluorocarbons or polyfluorocarbons which may contain an oxygen atom such as -3,6-thioxanonan and perfluoro-2-butyltetrahydrofuron; or mixed solvents thereof.

When selecting an organic solvent, consider the solubility of the quaternary onium salt, its phase separation from the aqueous phase, the operating temperature at which the method of the present invention is carried out, and the actual performance of the active onium salt obtained by the treatment method of the present invention. ) (An appropriate solvent is selected in consideration of the conditions used in the FPO synthesis reaction.

Among the above solvents, chlorinated hydrocarbons and hydrocarbons have Rf
, CO□○Q■ is excellent in that it has a high solubility.

In addition, the fluorine-containing solvent has good phase separation from the aqueous phase,
Moreover, it is excellent in that HFP and HFPO have high solubility.

As for the organic solvent in this HFPO production method, the same solvent or different solvents may be used in the HFPO synthesis step and the quaternary onium salt treatment step. however,
For ease of operation, it is preferred to use the same solvent unless there are particular operational constraints.

The hypochlorite used in the HFPO synthesis reaction step of the present HFPO production method may be one that liberates hypochlorite ions in the aqueous phase. Among these, sodium hypochlorite and calcium hypochlorite are particularly suitable because they are industrially mass-produced and can be obtained at low cost.

In addition, in the aqueous phase used in the HFP○ synthesis reaction step,
In addition to hypochlorite, the presence of an inorganic base such as sodium hydroxide results in a higher HFP conversion even under reaction conditions where a small amount of hypochlorite is added. It is also preferable because a good HFPO selection rate can be obtained.

As a method for carrying out the HFPO synthesis reaction step of the present HFPO production method, any of the batch method, semi-circulation method, and distribution method can be used.

After performing the HFPO synthesis reaction as described above, a part of the quaternary onium salt becomes the Q type to Rf and CO2 as described above, and such quaternary onium salt catalyst is repeatedly used to synthesize HFPO. When used in synthetic reactions, the catalyst activity gradually decreases. The cause of the gradual decline in catalyst activity is not clear, but it is probably due to an increase in the ratio of ■ to Rf and CO□ in the quaternary onium salt catalyst, and
, CO□ and ○, the number of those with low ion exchange capacity is considered to increase.

The ion source of thiocyanate ions used in the method of the present invention is not particularly limited as long as it forms thiocyanate ions in an aqueous solution, and various water-soluble thiocyanates may be used. Ru.

Examples of water-soluble thiocyanates include alkali metal salts such as sodium thiocyanate and potassium thiocyanate; alkaline earth metal salts such as calcium thiocyanate and barium thiocyanate; zinc thiocyanate, iron thiocyanate, and thiocyanate. Examples include, but are not limited to, ammonium acid.

However, in consideration of price, availability, etc., sodium thiocyanate, potassium thiocyanate, and ammonium thiocyanate, which are used in large quantities industrially, are advantageous as thiocyanate ion sources.

Activity-reduced quaternary onium salt Rfl in the method of the invention
There are no particular restrictions on the molar ratio of COZ○QO and SCN O.

However, if the molar ratio of SCN O/Rf + COz ``'Q■ is smaller than 1, complete Rf, CO□S
Virtually all RflCOZ
When trying to replace O, SCN○/Rf, Co
The molar ratio of g■Q■ needs to be 1 or more.

In practice, the molar ratio of SCN Q/RflCO□ towards O is usually 0.5<SCN○/Rr, c
ot OQ:E) <20 range h<, desired ma L<
The range of 0.8<SCN○/Rf+COz○mouthΦ<10 is particularly desirable, and 1<SCN O/Rf+
A range of COz○Q■<4 is used.

In addition, as a counter ion for Q■ of the quaternary onium salt, if an anion other than Rf+C (h○ group exists), when attempting to exchange substantially all Rf and CO□O, the mol of SCN○/Q■ The ratio needs to be 1 or more.

Further, the actual molar ratio of SCN○/Q■ is usually in the range of 0.5 to 20, preferably in the range of 0.8 to IO, and particularly preferably in the range of 1 to 4.

Even if anions other than RflCO□O are contained in the quaternary onium salt whose main component is RflCO2aQ'') with reduced catalytic activity, most of them are ion-exchanged with thiocyanate ions at the same time as Rf and CO□○. Therefore, it is not a particular problem.

However, significant amounts of hypochlorite ions may be entrained in the organic phase containing RflCO,h■. Since hypochlorite ion has the ability to oxidize thiocyanate ion, when hypochlorite ion is present in the organic phase, thiocyanate ion is removed during the ion exchange reaction between Rf1COz■q■ and thiocyanate ion. Some of the ions are decomposed by reaction with hypochlorite ions. Therefore, the fourth
If the content of hypochlorite ions in the onium salt is high, if necessary, the organic phase may be treated with a water-soluble solution such as sodium sulfite or sodium thiosulfate before contacting the organic phase with an aqueous solution containing thiocyanate ions. It is also possible to suppress the decomposition of thiocyanate ions during the ion exchange reaction by treating with an aqueous solution containing a reducing agent. Further, dissolving a reducing agent in an aqueous solution containing thiocyanate ions is also effective in suppressing decomposition of thiocyanate ions.

As a reaction method for the organic phase containing Rf, CO□θQ3) and the aqueous phase containing SCN○, any of the batch method, semi-flow method, and flow method, which are usually used as two-liquid phase reaction methods, can be used. It is. However, industrially, flow methods such as the countercurrent multistage contact reaction system and the continuous stirred tank type reaction system, which can be operated continuously, are advantageous. ○It is advantageous in that the amount used is small.

As the countercurrent multistage reaction apparatus, mixer settlers, rotating disk extractors, perforated plate extraction towers, stirring extraction towers, etc., which are commonly used for extraction operations, etc. can be used as they are.

The temperature at which the organic phase containing RflCOteQ and the aqueous phase containing scu 3 are reacted may be around room temperature and is not particularly limited, but if the temperature is too low, the ion exchange rate will be slow and the aqueous phase and Problems such as freezing of the organic phase occur, and if the temperature is too high, problems such as evaporation of the solvent occur. Therefore, typically -t o 'c~1
Temperature between 00°C and preferably -5°C to ao'c
A temperature between is selected.

In addition, in the above quaternary onium salt treatment step, Rf
The reason why the organic phase containing +COz direction○ is brought into contact with the aqueous phase containing thiocyanate ions is that after the FPO synthesis reaction, HFPO and unreacted RFP are removed from the organic phase by distillation or other operations. This may be before or after.

Conventionally, decomposition of SCN○ in an aqueous solution using an oxidizing agent such as sodium hypochlorite has been known as a method for decomposing SCNO, but an example of decomposition of 5cNE) in a hydrophobic solvent was reported by the present inventors. As far as I researched, it was unknown.

However, the inventors' studies surprisingly revealed that
Although quaternary onium thiocyanate is present in the organic phase, which is poorly miscible with water, various water-soluble oxidizing agents, including sodium hypochlorite, can improve the efficiency of quaternary onium thiocyanate. It was found that it decomposes.

As the water-soluble oxidizing agent used in the present invention, there are used various oxidizing agents that react with thiocyanate ions and decompose the thiocyanate ion structure. Examples include hypochlorites such as sodium hypochlorite, potassium hypochlorite, and calcium hypochlorite; chlorates such as sodium chlorate; secondary hypochlorous acid; chlorinated water; Chlorine-based oxidizing agents; Peroxide-based oxidizing agents such as hydrogen peroxide and L-butyl hydroperoxide; Nitric acid-based oxidizing agents such as nitric acid, nitrous acid, and sodium nitrate; or Persulfuric acid-based oxidizing agents such as sodium persulfate Examples include, but are not limited to, agents.

Among these water-soluble oxidizing agents, inorganic oxidizing agents are superior in that they are easily available and are less likely to remain in the organic phase. Among them, chlorine-based oxidizing agents, especially hypochlorites such as sodium hypochlorite and calcium hypochlorite, are easy to obtain and have excellent safety, operability, and reactivity. and is suitable for the method of the present invention.

In the method of the present invention, there is no particular restriction on the molar ratio of the water-soluble oxidizing agent to be reacted with the quaternary onium thiocyanate salt in the organic phase, but in order to sufficiently decompose SCN○, it is necessary to It is preferable to use a molar ratio of oxidizing agent/quaternary onium thiocyanate of 1 or more.

In practice, in consideration of economic efficiency, reaction efficiency, etc., the molar ratio of water-soluble oxidizing agent/quaternary onium thiocyanate is usually in the range of 2 to 100, preferably in the range of 2 to 20.
Particularly preferably, a range of 3 to 15 is used.

As a reaction method of the organic phase containing the quaternary onium thiocyanate salt and the aqueous phase containing the water-soluble oxidizing agent, the above-mentioned Rf,
A method exactly similar to the reaction method of the organic phase containing Co□■0■ and the aqueous phase containing SCN 3E can be used.

The temperature at which the organic phase containing the quaternary onium thiocyanate salt and the aqueous phase containing the water-soluble oxidizing agent are reacted may be around room temperature and is not particularly limited; however, if the temperature is too low, the reaction rate will be slow. If the temperature is too high, problems such as evaporation of the solvent may occur. Therefore, usually -10'C-10
A temperature between 0°C is chosen, preferably between ~5''C and 60'C.

The activation treatment of the quaternary onium salt containing Rf IC0z "Q"' may be performed every time the HFPO synthesis reaction is carried out, or may be carried out every time the HFPO synthesis reaction is carried out a plurality of times. Alternatively, when carrying out the HFPO synthesis reaction repeatedly, it is also possible to extract and activate a portion of the quaternary onium salt catalyst containing Rf IC0z OQ9 each time, and then add the activated product again. be.

FIG. 1 shows an example of a pronkturow sheet for carrying out the method of the present invention.

First, H in a two-phase system using a quaternary onium salt as a catalyst.
The FPO synthesis reaction [Step 1] is carried out, then the organic phase and the aqueous phase are separated [Step 2], and HFPO and unreacted HFP are distilled from the organic phase [Step 3]. The bottom solution of the distillation column contains I? with reduced catalytic activity. f, CO□□3Q■
Q○ S
CN (D) is formed, and then the organic phase containing Q○SCN○ is brought into contact with an aqueous solution of sodium hypochlorite, which is an oxidizing agent, to decompose the thiocyanate ion [Step 5] and form an active quaternary An onium salt is formed. The organic phase containing the activated quaternary onium salt obtained by the above operation is used again as an organic phase in the HFPO synthesis reaction [Step 1].

Note that Step 1 and Step 2 may be carried out in separate apparatuses, but if Step 1 is carried out in a batch reaction, Step 2 can also be carried out in the same apparatus.

By adopting the method described above, the quaternary onium salt catalyst, whose activity has decreased, can be activated through simple operations under mild conditions, making it economical to repeatedly use the hydrophobic quaternary onium salt catalyst. HFPO manufacturing process becomes possible.

Furthermore, in this method, Rf +COz ”
It is also a great effect that the by-products Rf and CO□・D can be recovered from the aqueous phase after the ion exchange reaction of Q9 and 5CN. )(In the FPO synthesis reaction step, the reaction is often carried out in the presence of a larger amount of hypochlorite than is required for the HFP epoxidation reaction.

Therefore, if a sufficient amount of hypochlorite exists to carry out both the oxidative decomposition of Q○ SCN Er and the epoxidation reaction of RFP, the above two reactions can be carried out simultaneously. It is also possible to implement.

That is, in the "method for producing HFPO including a quaternary onium salt activation treatment step" of the present invention, the organic phase containing EE'scNg produced in step (1) is directly heated to HF.
By using it as an organic phase in the PO synthesis reaction, it is also possible to carry out the decomposition of step (ii) (scN+'') and the step (synthesis) at the same time.

However, this operation is usually carried out when the molar ratio represented by formula (n) is 1 or more, preferably in the range of 2 to 100, particularly preferably in the range of 2 to 20.

As mentioned above, the HFPO synthesis reaction step is usually carried out in the presence of a larger amount of hypochlorite than is required for the RFP epoxidation reaction.

So in a case like this:! , l-(F P O
Unreacted hypochlorite remains in the aqueous phase after the synthesis reaction.

In addition, the present inventors have determined that the HFPO synthesis reaction phase is “F-
As analyzed by NMR spectrum, R in the organic phase
f, Rf in C020 mouth, CO□ (species i similar to
The presence of the fluorine-containing carboxylic acid ion of Q was confirmed. Rf + COz (' (forming ion bears with metal cations such as sodium cations) in this aqueous phase is
Rf in the organic phase mentioned above, Rf in CO2・”Q・Rin
, CO□O is thought to be a by-product during the HFPO synthesis reaction, using the same mechanism as CO□O.

The composition distribution of Rf+Go2(-) in the aqueous phase changes depending on the reaction conditions, but the proportion of CF3Co□' is higher than that of Rf and Co□○ in the organic phase. For example, in the reaction example of Example 8, Rf in the aqueous phase, CF in CO□・D,
The proportion of CO□O is 88%.

As mentioned above, in addition to unreacted hypochlorite, CF, C
Rf+COZ O whose main component is O□D exists.

When the present inventors used this wastewater phase as an aqueous solution containing a water-soluble oxidizing agent in step (ii) of "Production method J of HF PO including a quaternary onium salt activation treatment step" of the present invention. , Q□3SCN in the organic phase and SCN in the middle
The formation of a quaternary onium salt with high ion exchange activity by the decomposition of ○ and the extraction of RflCO2"' in the aqueous phase by the active quaternary onium salt were simultaneously carried out. As a result,
In the organic phase, Rf, C(h'''Q-) containing CF3Co□5)Q5) as a main component was formed.

The present inventors obtained CF3Co by the above treatment method,
A quaternary onium salt containing Oq■ as a main component, I]FPO
When used as a catalyst for a synthetic reaction, it was found to exhibit sufficient catalytic activity. This result was a completely unexpected finding since the catalytic activity of the quaternary onium salt containing CF:1CFXCO, -Q9 as the main component in the HFPO synthesis antisynthesis reaction phase is low and requires activation treatment. Met.

The reason for such a difference in catalytic activity is not clear, but it is likely that CF3C0 than CF3CFXCOz 3Q■
Z3Q○ has lower ion bear stability, so CF
□CO□○Q (S) CF:l This is probably because CO□○ easily exchanges ions with hypochlorite ions (QCff○) to easily form an active ion pair Q■ocpa.

Therefore, in the HFPO production method J of the present invention, which includes the fourth treatment step of activating an onium salt, step (i)
As an aqueous solution containing a water-soluble oxidizing agent, the HF P O
It is possible to use a wastewater phase containing unreacted [F]hypochlorite produced in the synthesis reaction step.

In this case, it is desirable that the number of moles of hypochlorite ions in the wastewater (■) before the treatment is greater than the number of moles of Q■SCN○ in the organic phase in step (ii). , more preferably 2 to 100 times, and more preferably 3 to 15 times.

However, in the HFPO manufacturing process that includes the activation treatment process of quaternary onium salts using the wastewater phase, RflCO2- extracted from the wastewater phase is recycled to the HFPO synthesis reaction process, so as the number of recycling increases, the wastewater The Rr, co2:G concentration in the phase increases, and eventually the quaternary onium salt catalyst in the organic phase can no longer perform extraction alone, making long-term continuous operation impossible. Also, of course, Rr in the wastewater phase
, co23 is larger than the quaternary onium salt catalyst in the organic phase, Rf and CO□D in the aqueous phase cannot be completely extracted.

Therefore, the present inventors solved the above problem and
In order to find a way to operate the manufacturing process continuously and stably,
As a result of further intensive studies, we discovered the following method of treating the wastewater phase using Q.E)SCN■ with a mole number greater than that required as a catalyst.

That is, in the "method for producing HF PO including the activation treatment step of a primary onium salt" of the present invention, the aqueous solution containing the water-soluble oxidizing agent in step (ii) is used in the hexafluoropropylene oxide synthesis reaction. It is a wastewater phase containing unreacted hypochlorite and by-product fluorine-containing carboxylate produced in the process, and the organic phase treated with the wastewater phase is divided into two parts, and one is divided into two parts, and one is divided into two parts, and one part is separated from the hexafluoropropylene oxide. It is used as the organic phase in the synthesis reaction step, and the other is used in the step (i
) A step of simultaneously carrying out activation treatment of a quaternary onium salt characterized by helicycle and contacting with an aqueous phase containing thiocyanate ions and removal of a by-product fluorine-containing carboxylate from a wastewater phase. We have discovered a method for producing hexafluoropropylene oxide.

In addition, in this operation, the number of moles of the quaternary onium salt in the organic phase to be recycled in step (i) is the Rf in the wastewater phase.
The number of moles of +C0zO, the number of moles of quaternary onium salt in the organic phase used in the HFPO synthesis reaction, or the number of moles of H
It is determined in consideration of the FP○ synthesis reaction results, Rf, CO□○ extraction processing conditions, etc.

Usually, in the above reaction method, the number of moles of the quaternary onium salt catalyst used in the HFPO synthesis reaction step and the step (
i) The total number of moles of quaternary onium salts in the organic phase to be helicycled (i.e. the number of moles of quaternary onium salts used in step (i) and step (ii)) is
Desirably 1% to 100% by mole of H F P produced in the O synthesis reaction step.
Operating conditions are determined so that the content ranges from 0 mol % to 60 mol %.

In this HFPO manufacturing method, step (i) and step (ii)
If the number of moles of the quaternary onium salt used in ) is too small, the extraction of Rf+COz○ from the aqueous phase will be insufficient, and if it is too large, the operating cost will increase, which is not preferable.

In addition, in this HFPO production method, the number of moles of hypochlorite ions in the wastewater phase from the HFPO synthesis reaction step is
It is desirable that the number of moles is larger than the number of moles of Q'F) SCN O in step (i), more desirably in the range of 2 to 100 times, and particularly in the range of 2 to 20 times as practical.

FIG. 2 shows an example of a block flow sheet for carrying out the method of the present invention.

[Step 6], [Step 7], and [Step 8] are the same steps as the HFPO synthesis reaction step [Step 1], the phase separation step [Step 2], and the distillation step [Step 3] in FIG. 1, respectively.

In the ion exchange reaction step (Step 9), an organic phase containing Rf+COz□○Q■ whose main component is ChCFXCO□OQ■ (X=F, IJ, H) from [Step 8];
A part of the organic phase containing the quaternary onium salt mainly composed of CF3CO□○Q■ from Step 10] was combined with N
By contacting with a5CN aqueous solution, an organic phase containing mE)scN○ is formed by ion exchange reaction. Next, the organic phase containing Q■SCN:)
Step 10], the wastewater phase containing the unreacted hypochlorite from [Step 7] and the fluorine-containing carboxylic acid salt containing CFjCO□F)Na as a main component is contacted to form SCN.
Activation of quaternary onium salt by decomposition of 3 and Rf, CO
Extraction of □ is performed at the same time.

The organic phase from [Step 10] is divided into two parts, one of which is used as the organic phase in the HFPO synthesis reaction step of [Step 6],
The other is recycled to [Step 9].

By operating as described above, substantially all of the Rf and CO20 by-produced in the HFPO synthesis reaction step [Step 6] can be separated as an Rf, Co□Na aqueous solution in [Step 9]. Therefore, it becomes possible to keep the Rf + COz '' concentration in the wastewater phase from the HFPO synthesis reaction process constant.

(Effect of the invention) The zero HF PO production method allows stable continuous operation for a long period of time. In addition, wood HFPO production is an extremely simple method that can activate the catalyst and separate Rf and Co20 at the same time, and is industrially useful.

(Example) The present invention will be explained below with reference to Examples.
The scope of these examples is not intended to be limiting.

Example 1 <HFPO synthesis reaction> Stirring rod coated with fluororesin, thermocouple nozzle, pressure gauge, cooling device, reaction liquid sampling nozzle [A
], Furthermore, a pressure-resistant glass reactor having an internal volume of 300 mm and equipped with a nozzle (B) for filling and extracting the reaction solution and product is used for the HFPO synthesis reaction.

First, trioctyltrimethylammonium chloride (hereinafter abbreviated as "TOM AC") 0. 1,1,2-trichloro-1,2,2-trifluoroethane (hereinafter abbreviated as "F-113") solution 1 containing 580 g (1,44 mmol)
60d and 70d of an aqueous sodium hypochlorite solution containing 1.5% by weight of sodium hydroxide and an effective chlorine concentration of 6%.
Fill it. After cooling the contents to -5°C
6.20 g of cooled HPF was charged and the reaction solution was vigorously stirred to start the reaction.

During the reaction, the reactor is cooled so that the temperature of the reaction solution is in the range of 15°C to -3°C.

Stirring was stopped 1 minute, 2 minutes, 5 minutes, and 10 minutes after the start of the reaction, and the reaction product was analyzed by gas chromatography. As a result, the HFPO selectivity was about 80% at any reaction time. On the other hand, the RFP conversion rate was as shown in Table 1, and the reaction was completed after 10 minutes.

After 10 minutes of reaction, the pressure inside the reactor is reduced, and HFPO and about 40% F-113 are removed from nozzle CB). Next, the inside of the reactor was brought to atmospheric pressure, the aqueous phase was removed from nozzle CB], and instead, 10 ml of a sodium hypochlorite aqueous solution with an effective chlorine concentration of 6% containing 1.5% by weight of sodium hydroxide was added. Fill it. In addition, F-113 reduced by the depressurization process is also replenished. The reactor is then sealed and
After cooling the contents to -5'C, F cooled to -5'C.
(Fill 4.20g of FP, and all subsequent operations will be performed in the first place.)
In the same manner as the first HFPO synthesis reaction, the second HFPO synthesis reaction
Perform PO synthesis reaction.

When the above reaction operation was repeated, the reaction rate in the 20th reaction was lower than that in the first reaction, as shown in Table 1.

Table 1 Example 2 Structure of catalyst> The decrease in reaction rate due to repetition of the HFPO synthesis reaction as shown in Example 1 is due to the TOMA used as a catalyst.
This is thought to be due to a change in the structure of C(Q, czO).

Therefore, F-11 after 20 repeated reactions in Example 1
When the structure of the catalyst in the 378 liquid was investigated, the following results were obtained.

(2) A characteristic absorption band of fluorine-containing carboxylate anions was observed at 1695 cm-' in the infrared absorption spectrum.

■'H-NMR spectrum 01 ■ part (trioctylmethylammonium cation part) was confirmed to be unchanged.

■”F-NMR spectrum The signal shown below was observed, and the “F-NMR spectrum” of the standard substance was observed.
- From comparison with NMR spectrum data, CF3CFX
COzO (x=F, CL H) and CFIC (hc
) and other fluorine-containing carboxylate anions ((:P3C
The presence of FXCO20/ChCO□○; 85/12 molar ratio) was suggested.

CF3-CFz-C(hOCF3-CFCI-CO
zO79,140,182,630,6 CF3-CFH-Co□○ CF3-CO2 (from the result of 0 or more, TOMAC (Q
, ■ 10) C, after 20 times (7) Fl repeat reaction,
It was found that most of the salts were Rf, Co□○g, and Q type quaternary ammonium salts.

This Rf, CO□○ in Q1■ is,
It is a fluorine-containing carboxylate anion having 2 or 3 carbon atoms, and H produced in the process of the HFPO synthesis reaction in Example 1.
This is thought to be due to side reaction products derived from FPO or HFP.

In addition, the F-113: mixture containing Rf, CO□3g, 0 was stirred with an aqueous solution containing 5 times the mole of sodium hypochlorite and 5 times the mole of sodium chloride as Rf, Co□○ Q10. But a small amount of l? f, CO2CO, one to q, 0ocx○ or Q■ci! , o only ion exchange occurred.

Shitakatte, Rf+COz○Qla no Ka, Q, ■cp
The reason why the catalytic activity is lower than that of O is because Rf+CO20 is Q,
■Because it forms a stable ion bear, HFPO
In the synthesis reaction, Rf, C in CO□001■
Since 02S is difficult to ion exchange with OCr○, HFPO
Q, 90CP, which is considered to be a reactive species in the synthesis reaction
This seems to be because ■ is difficult to form.

Example 3 <Catalyst regeneration treatment> Quaternary ammonium salt catalyst with reduced activity obtained by the same method as Example 1 1. 44. mmol (RLC0
2) Contains 90 mol% or more of Q and (2). ) containing F
Ion exchange treatment was performed by stirring 160 d of the -113 solution with 20 ml of an aqueous solution containing 5% by weight of Na5CN at 30°C for 10 minutes. After this ion exchange treatment, Rf, Co
Approximately 70 mol% of □OQ■ pr, co, (E) is SC
It was found by infrared absorption spectrum analysis of the quaternary onium salt that N was exchanged with: (ν,.

8.T: 2050cm-'). When this ion exchange treatment was repeated 10 times, it was found by infrared absorption spectrum analysis that almost all of the quaternary onium salt in the F-113 solution had been converted to q,9scN◯.

The total amount of Q + QSCN c) containing F-113 phase produced by the above treatment operation and 1.5% of sodium hydroxide. 5% by weight of sodium hypochlorite aqueous solution with an effective chlorine concentration of 6% was filled into a 300 ml eggplant flask equipped with a stirrer, and stirred vigorously for 15 minutes at a bath temperature of 30°C. did. As a result, SC of 01 in F-113 phase
It was confirmed by infrared absorption spectrum analysis that all SCN○ of N (E) was decomposed.

Example 4 <HFPO synthesis reaction using regenerated catalyst> F-113? containing 1.44 mmol of the quaternary ammonium salt catalyst obtained by the treatment in Example 3. :8 liquid 160m
1 and I? containing 1.44 imol of TOMAC. 11
The same HF PO synthesis reaction as in Example 1 was carried out using this solution instead of 160 d of the 3 solution.

The reaction results are shown in Table 1, and it was confirmed that the catalyst obtained by the regeneration treatment of Example 3 exhibited an activity equivalent to that of TOMAC.

Example 5 <Continuous synthesis reaction of HFPO (i)> A tubular reactor with an internal volume of 1.2P as shown in Fig. 3 (
ii,), decanter (12), HFPO distillation column (13)
), and a continuous reaction apparatus equipped with an organic phase tank [14], HF PO was synthesized from HFP.

First, the tubular reactor [11] was cooled to -5'C, and 1
．． F-113 solution containing 2% by weight TOMAC,
Circulate through the reactor at a flow rate of 9.41/hr.

Next, a sodium hypochlorite aqueous solution containing 1.0 mol/β of sodium hypochlorite and 1.5% sodium hydroxide was placed in the tubular reactor [11] at 3.0 mol/β.
2I! /hr, and simultaneously discharged from the decanter [12].

HFP in a tubular reactor with a flow rate of 0.5 kg/hr.
(ii) by being fed to the organic phase line before
A continuous synthesis reaction of HFPO is started.

The reaction liquid exiting the tubular reactor [11] is transferred to a decanter [
12] into an organic phase and an aqueous phase, and the aqueous phase is discharged from the reactor. The organic phase containing the produced HFPO is HFP
O is sent to the distillation column [13], where the produced HFPO and unreacted RFP are separated from the organic phase by distillation. HF
The residual organic phase after PO and HFP are distilled off is sent to the organic phase tank (14) and from there to the tubular reactor [11
] Helicycled.

According to post-reaction gas chromatography analysis, 15 minutes after the start of the reaction, the HFP conversion rate was 9.
It was 9% or more, and the HFPO selection rate was 81%. However, after 30 hours of continuous reaction, the conversion of RFP had decreased to 72%.

Example 6 The structure of a quaternary onium salt catalyst whose activity in the organic phase decreased after 30 hours of continuous reaction in Example 5 was investigated in the same manner as in Example 2. As a result, most of the quaternary onium salt catalysts are of the Rf, Co□○Q■ type,
And CF3CFχCO□O(X
The molar ratio of =F, cp, H)/CF3CO□O was 84/16.

The organic phase containing this activity-reduced quaternary onium salt was treated in the following manner to activate the catalyst.

First, using a jacketed multistage countercurrent extraction column with a column diameter of 40 plates and having 10 stages of stirring chambers partitioned by perforated plates,
The organic phase 61 and a 2% by weight aqueous solution of Na5CN 8! of,
When they were brought into contact in a countercurrent manner at a jacket temperature of 15°C, almost all of the quaternary onium salt in the organic phase was Q■SCN○.

In a reactor with an internal volume of 10 f, first, 6 f of F-113 solution containing Q (E) SCN○ obtained by the above method (some of it exists in a suspended state)! , and then, while stirring the F-113 solution, 1N sodium hypochlorite aqueous solution 3β containing 1.5% by weight of sodium hydroxide was added until the reaction solution temperature exceeded 40 °C. Add gradually to avoid

After the addition was completed, stirring was continued for 15 minutes at 40°C,
When the contents of the organic phase were analyzed by infrared absorption spectroscopy, it was confirmed that all of SC to S in Oscu 8 had been decomposed.

F-11,3 solution containing quaternary onium salt obtained by the above treatment 5! 1. 2% by weight TOMA
used in place of F-113 solution containing C, and
The same HFPO synthesis reaction as in Example 5 was carried out by supplying the aqueous phase to the continuous reaction device before the organic phase. R
15 minutes after starting the supply of FP and organic phase, the reaction liquid from the tubular reactor [11] was analyzed by gas chromatography, and the RFP conversion rate was 99% or more, and the HFPO selection rate was 80%. %Met.

From this result, it was confirmed that by treating the catalyst with reduced activity by the method described above, a catalyst exhibiting reaction results equivalent to TOMAC was formed.

Example 7 Using the F-113 solution containing qDscN obtained in the middle of the operation of Example 6, Qsc: h31.44
F-11,3 solution containing +1111101 160
MFL was made into 3 molds.

Next, 160 ml of the F-113 solution obtained in this way
1.100 ml of sodium hypochlorite/water mixture containing 1.5% by weight of sodium hydroxide and an effective chlorine concentration of 6%
, and 4.20 g (28 mmol) of HFP were used to carry out the same reaction as in Example 1.
The RFP conversion rates after 1 minute, 5 minutes, and 10 minutes were 60%, 93%, and 100%, respectively, and the Q■c of Example 1
Reaction results close to those of the HFPO synthesis reaction using p○ were obtained. Note that the HFPO selection rate was approximately 80% at all reaction times.

Example 8 <Continuous synthesis reaction of HFPO (ii)> The same continuous synthesis reaction of HFPO as in Example 5 was carried out, but the flow rate of the sodium hypochlorite aqueous solution was changed to 9.81! instead of 8.2ffi/hr! , /hr, and F containing TOMAC
- The flow rate of the 113 solution was changed to 1.4 ff/hr instead of 9.4 ff/hr.
51/hr, and the RFP supply rate is 0.5 kg.
/hr instead of 0.4kg/hr.

As a result, at the outlet of tubular reactor Cii],
Thirty minutes after the start of HFP supply, the RFP conversion rate was approximately 100% and the HFPOi abundance rate was 78%.

Furthermore, the HFP conversion rate 5 hours after the start of HFP supply was 9.
6%, and the HFPO selectivity was 81%.

In the above continuous synthesis reaction of HFPO, approximately 20 ff of wastewater phase was obtained between 3 and 5 hours after the start of HFP supply.
Inside CFjCO□○/CF3CFXCOZ・O (x=F
, Cj! , H) was 88/I 2 and the pH of this aqueous phase was 12.5.

Example 9 The HFPO production process shown in FIG. 2 was carried out by incorporating a catalyst activation step and a wastewater treatment step into the HFPO synthesis step in Example 8 as shown below.

[Step A (corresponding to step 10)] Waste water 9°82 (
corresponding to the amount of wastewater produced per hour) and Q 'E'
F-1 containing SCN Oo, 047 mol/f
When 22.5 f of the No. 13 solution was brought into countercurrent contact with a multistage countercurrent extraction column, SCN O in the organic phase completely disappeared, and most of Rr, co, and C) in the wastewater phase were extracted into the organic phase. Tep
f, co□QQS was formed.

[Step B (corresponding to Step 11, Step 12 and Step 13)
] Organic phase containing Rf, CO□OQO obtained in [Step A] 7.5! When the same operation as in Example 8 was carried out using H as the organic phase, the RFP conversion rate at the outlet of the tubular reactor was 99% or more 30 minutes after the start of the reaction, and H
FPO selectivity was 81%.

Comparing this reaction result with the reaction result of Example 8, it was found that the quaternary onium salt catalyst obtained in [Step A] was better at 5 hours after the start of the reaction in the catalyst recycling reaction method of Example 8. The activity is higher than that of the quaternary onium salt catalyst of HFP.
This shows that it can be used satisfactorily as an O synthesis reaction catalyst.

[Step C (corresponding to Step 9)] 7,542 organic phases containing Rf+CO□OO■ obtained in [Step A] (0.5 of the organic phase recycled to Step 9)
) and 5 hours after the start of the reaction in Example 8.
The organic phase containing the quaternary onium salt catalyst with reduced catalytic activity obtained from the HFPO distillation column bottoms during 0.5 hours between 3.7 and 5.5 hours! l was mixed.

This mixed solution 11.25E (R "+CO supplied to step 9"
(corresponds to 0.5 hours of organic phase containing z○Q■)
When an aqueous solution 5i containing 200 g of Na5CN and 200 g of Na5CN was brought into countercurrent contact in a multistage countercurrent extraction column, the quaternary onium salt in the organic phase was mostly Q'E) SCN.

From the above results, it was confirmed that the HF PO production process including the catalyst activation and waste water treatment steps shown in FIG. 2 could be implemented.

Example 10 First reaction> Internal volume 100111i equipped with a stirring device! In a pressure-resistant reaction vessel, 60 d of toluene, 2 g of a sodium hypochlorite aqueous solution with an effective chlorine concentration of 6% containing 1.5% by weight of sodium hydroxide, 2g of H, FPI, and tri-octyl ethylphosphonium as a catalyst Bromide 0.2
Fill 5g. Next, after cooling this reaction solution to -5° C., the reaction solution in the reaction container is mixed to start the reaction.

When the reaction results after 20 minutes were analyzed by gas chromatography, the conversion rate of RFP was 86% and the HFPO selectivity was 66%.

After the reaction, collect the organic phase from the reaction vessel and transfer it to the evaporator ~
The solvent and low boilers were removed. According to the infrared absorption spectrum of the residue, as in Example 2, the presence of fluorine-containing carboxylate anions was observed.

<Second reaction> Dissolve all the residue obtained by the above operation in toluene 60, and use this organic phase to react with HFP in the same manner as in the first reaction.
When the O synthesis reaction was carried out, after 20 minutes of reaction, HF
The conversion rate of P was 77%.

<Catalyst activation treatment> Collect the organic phase from the reaction vessel after the second reaction,
The solvent and low-boiling substances were removed using an evaporator. All this residue was dissolved in 1001n1 of toluene and this solution was prepared in the same manner as in Example 3 with 10% by weight of Na5CN.
An ion exchange reaction was carried out by contacting with aqueous solution 30d three times.

Toluene solution containing trioctylethylphosphonium thiocyanate obtained by the above operation 1001n1
and an aqueous solution of sodium hypochlorite having an effective chlorine concentration of 12% were filled into an eggplant flask having an internal volume of 20 i, and mixed vigorously at a bath temperature of 30°C.

Thereafter, the contents in the organic phase were analyzed by infrared absorption spectroscopy, and it was confirmed that most of the SCN O in the organic phase had been decomposed.

<Reaction using activated catalyst> 100 d of toluene solution containing the activated quaternary phosphonium salt catalyst obtained by the above catalyst activation treatment was concentrated to 60 d using an evaporator. Using 60d of this solution as the organic phase, the same HFPO synthesis reaction as in the first experiment was carried out, and the HFP conversion rate after 20 minutes was 88%, confirming that the catalyst activity was almost the same as in the first experiment. .

This result shows that the above catalyst activation treatment method is effective for this catalyst.

Example 11 Trioctylmethylammonium thiocyanate salt 1.4
160 precepts of F-113 solution containing 4 mmol and 12% effective chlorine concentration containing 2% by weight of sodium hydroxide.
(hypochlorous acid) and 20 d of IJium aqueous solution at 30°
After mixing at C for 30 minutes, it was confirmed by infrared absorption spectrum analysis that most of the SCN O in the organic phase had disappeared.

160 ml of F-113 solution containing 1.44 mmol of quaternary ammonium salt catalyst obtained by the above treatment method
When the same reaction as in Example 1 was carried out using the organic phase, the HFP conversion rate was approximately 100 in a reaction time of 10 minutes.
%, and the catalyst obtained by the above treatment method is TOMA
It was confirmed that it exhibited almost the same activity as C.

Examples 12-14 In the same manner as in Example 11, SCN O in trioctylmethylammonium thiocyanate was prepared using an aqueous solution containing various water-soluble oxidizing agents such as hydrogen peroxide, nitric acid, and chlorine water.
I tried to disassemble it. However, the oxidizing agent concentration was 2N, the oxidizing agent/5CNa molar ratio was 30, and stirring was performed at 30° C. for 1 hour.

As a result, it was confirmed by infrared absorption spectrum analysis that most of the SCN○ in the organic phase had disappeared.

F-113 solution containing 1.44 mmol of quaternary ammonium salt catalyst obtained by the above treatment method 160-
The same reaction as in Example I was carried out using as the organic phase. The reaction results are shown in Table 2 together with the results of Examples 1 and 11, and in both catalyst treatment methods, catalysts with approximately the same level of activity as TOMAC were obtained.

Table 2

[Brief explanation of the drawing]

Figure 1 shows H
A block flow sheet of an example of the FPO production method, FIG. 2, is an example of the HFPO production method including a step of simultaneously carrying out the activation treatment of the quaternary onium salt and the removal of the by-product fluorine-containing carboxylic acid salt from the wastewater phase. Figure 3 shows the block flow sheet for HF using a quaternary onium salt catalyst repeatedly.
This is an example of an apparatus for manufacturing PO.

Claims (4)

[Claims] (1) General formula [I] R_1R_2R_3R_4A^■ [I] (However, A represents N or P atom, R_1, R_2
, R_3 and R_4 represent a substituted or unsubstituted hydrocarbon group. The total number of carbons in R_1, R_2, R_3 and R_4 is at least 8 per onium ion. R_1, R_2, R_3 and R_4 may be linked to each other to form a heterocycle, or R_1, R_2,
R_3 or R_4 may contain other onium ions. ) A two-phase system consisting of a water-immiscible organic phase containing a catalyst consisting of a salt of a quaternary onium cation shown in In the method for producing hexafluoropropylene oxide, (i) a quaternary fluorine-containing carboxylic acid with reduced catalytic activity produced by the hexafluoropropylene oxide synthesis reaction;
(ii) contacting an organic phase containing a quaternary onium salt with an aqueous phase containing thiocyanate ions to form a quaternary onium thiocyanate salt in the organic phase;
The organic phase containing the onium salt is brought into contact with an aqueous solution containing a water-soluble oxidizing agent to decompose thiocyanate ions, and (iii) the obtained organic phase is used again as an organic phase for the hexafluoropropylene oxide synthesis reaction. A method for producing hexafluoropropylene oxide, comprising a step of activating a quaternary onium salt. (2) In the method according to claim 1, the aqueous solution containing the water-soluble oxidizing agent in step (ii) contains unreacted hypochlorite produced in the hexafluoropropylene oxide synthesis reaction step. A method characterized in that the wastewater phase. (3) In the method according to claim 1, the aqueous solution containing the water-soluble oxidizing agent in step (ii) is mixed with unreacted hypochlorite and by-products produced in the hexafluoropropylene oxide synthesis reaction step. The organic phase, which is a wastewater phase containing a fluorine-containing carboxylic acid salt and which has been treated with the wastewater phase, is divided into two parts, one of which is used as the organic phase of the hexafluoropropylene oxide synthesis reaction step, and the other of which is used in step (i). )
Hexane containing a process of simultaneously carrying out the activation treatment of the quaternary onium salt characterized by recycling it into aqueous phase containing thiocyanate ion and removing the by-product fluorine-containing carboxylate from the wastewater phase. A method for producing fluoropropylene oxide. (4) In the method according to claim 1, by using the organic phase containing the quaternary onium thiocyanate produced in step (i) as it is as the organic phase for the hexafluoropropylene oxide synthesis reaction. , decomposition of thiocyanate ion in step (ii) and step (iii)
) at the same time.