JP2003089663A - Method for producing perfluoro organic bromide - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method for producing a highly pure perfluoro organic bromide from an easily available raw material by an easy process. SOLUTION: The perfluoro organic bromide expressed by R<f> Brn such as CF3 (CF2 )7 Br, or the like, is produced by reacting a compound expressed by R<f> (COF)n such as CF3 (CF2 )7 COF, or the like, with a brominating agent. Here, R<f> expresses an (n) valent perfluoro organic group; (n) expresses an integer of L4.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a synthetic intermediate, a method for producing a perfluoroorganic bromide useful as a halon-based extinguishing agent, a flame-retardant additive for trans oil or electric insulating oil, an X-ray contrast agent, and the like. .

[0002]

2. Description of the Related Art Since perfluoroorganic bromides have a relatively weak bonding force between a perfluoro group and a bromine atom, the fact that the bond is easily cleaved by a radical or the like is utilized to make use of a perfluoro group such as a perfluoroalkyl group. It is used as an introduction agent of. Further, perfluoroorganic bromide is used as a synthetic raw material for fluorine-containing products such as surfactants, agricultural chemicals, and pharmaceuticals, or as a cross-linking agent for fluororubber. Further, the perfluoroorganic bromide is also useful as a halon-based fire extinguishing agent, a flame retardant additive for transformer oil or electric insulating oil, an X-ray contrast agent, and the like.

As a conventional method for producing a perfluoroorganic bromide, (a) a method of decarbonylating a nitrogen-containing perfluorocarboxylic acid bromide under irradiation of ultraviolet rays (JP-A-5-229992), (b) a nitrogen-containing perfluorocarboxylic acid Bromide and lithium bromide at 200 to 500 ° C
Method of heating by heating to react (JP-A-2-26254)
(0), (c) A method of reacting perfluoroalkyl iodide with bromine in the presence of a radical initiator (JP-A-6-36187).
0-184033) is known.

[0004]

However, the nitrogen-containing perfluorocarboxylic acid bromide, which is the raw material for the methods (a) and (b), is a compound of high purity because it is a compound that is difficult to obtain and difficult to purify. There is a difficult problem to get. That is, the nitrogen-containing perfluorocarboxylic acid bromide is produced by fluorinating a carboxylic acid ester or halide by an electrochemical fluorination reaction in HF, and then reacting it with expensive lithium bromide at 230 to 270 ° C. ing. There is a disadvantage in that it is economically disadvantageous because expensive lithium bromide is used. Further, since it is difficult to obtain a high-purity raw material, there is a problem that a large amount of impurities are contained in the product.

The method (c) has a problem that the raw material perfluoroalkyl iodide causes the line to be clogged during the reaction. In addition, the product contains iodine compounds derived from raw materials, and there are problems that the iodine compounds cause coloring and other problems, and that a purification process for removing the iodine compounds requires time and effort.

[0006]

The present invention provides a method for producing an intended perfluoroorganic bromide from a starting material of perfluorocarboxylic acid fluoride containing no iodine atom.

That is, the present invention provides a method for producing a perfluoroorganic bromide represented by the following formula (2), which comprises reacting a compound represented by the following formula (1) with a brominating agent. . R ^f (COF) _n ··· Formula (1) R ^f Br _n ··· (2) However, the symbols in the formula have the following meanings. R ^f : Perfluoro n-valent organic group. n: An integer of 1 to 4.

[0008]

BEST MODE FOR CARRYING OUT THE INVENTION In the present specification, a compound represented by the formula (1) is referred to as a compound (1). The same applies to compounds represented by other formulas.

R ^f in the compound (1) is a perfluoro n-valent organic group. The perfluoro n-valent organic group refers to a group in which all the hydrogen atoms present in the n-valent organic group are substituted with fluorine atoms. Here, the organic group means a group in which the C—H portion is essential. As the n-valent organic group, an n-valent saturated hydrocarbon group, an n-valent (containing an etheric oxygen atom) saturated hydrocarbon group,
Alternatively, an n-valent (nitrogen atom-containing) saturated hydrocarbon group is preferable.

The carbon number of R ^f is preferably 1 to 12, particularly preferably 4 to 16, and particularly preferably 6 to 12. The compound (1) in the present invention may be one kind or two or more kinds in which R ^f has different carbon numbers, and the compound (1)
When is a compound of two or more, it is preferable that the average carbon number of R ^f is 6 to 12.

The structure of R ^f may be a linear structure, a branched structure, a ring structure, or a structure partially having a ring structure. From the viewpoint of easy availability, a linear structure is preferable.

N in the compound (1) is a group (R^f)of
Is the number of bonds, and the group (R ^f) -C
It means the number of OF groups. n is 1 to 4 and is 1.
Is preferred. That is, as the compound (1), the following compound
The thing (1-1) is preferable. R^f1-COF ... Formula (1
-1) However, R^f1Is a perfluoromonovalent organic group
Perfluoroalkyl group, perfluoro (ether
Oxygen-containing alkyl) group, perfluoro (nitrogen atom)
Included alkyl) groups, etc., and perfluoroalkyl
Groups are preferred.

The number of carbon atoms of R ^f1 is the same as that of R ^{f in} a preferable aspect of the structure. In the case R ^{f 1} is a branched structure is preferably a structure in which there are branches in the terminal portion of R ^f. R ^f1 is particularly a straight-chain perfluorooctyl group having 8 carbon atoms (F
_{(CF 2) 8 -)} and it is preferably.

Specific examples of R ^f1 include the following. Further, as a specific example of the case where R ^f is a divalent to tetravalent perfluoro organic group, a group in which 1 to 3 of the fluorine atoms in the group shown in the specific example of R ^f1 below serve as a bond is mentioned.

F (CF_Two)_Four-, F (CF_Two)₅-, F
(CF_Two)₆-, F (CF_Two)₇-, F (CF_Two)
₈-, F (CF_Two)₉-, F (CF_Two)₁₀-, F (C
F_Two)_{1 1}-, F (CF_Two)₁₂-, F (CF_Two)_Thirteen
-, F (CF_Two)₁₄-, F (CF_Two)₁₇-, H (C
F_Two)₈-, (CF_Three)_TwoCF (CF_Two)₆-, (CF
_Three)_TwoCF (CF_Two)₈-, (CF_Three)_TwoCF (C
F_Two)₁₀-, Cl (CF_Two) ₈-, F (CF_Two)_ThreeO
CF (CF_Three)-, CF_ThreeCF_Two[CF_TwoOCF (CF
_Three)]_Two-, CF_ThreeCF_Two[CF_TwoOCF (CF_Three)]
_Three-, F (CF_Two)_ThreeOCF (CF_Three) OCF_TwoCF_Two
-, CF_ThreeCF_Two[CF_TwoOCF (CF_Three)]_TwoOCF
_TwoCF_Two-, Perfluorocyclohexyl group, (CF_Three
CF_Two)_TwoN (CF_Two)_Three-, CF_Three(CF_Two)_TwoOC
F (CF_Three) CF_TwoOCF (CF_Three)-.

[0016]

[Chemical 1]

The compound (1) as a raw material of the method of the present invention is
It is a known compound or a compound that can be easily produced from a known compound. As a method of obtaining the compound (1),
For example, a method of decomposing the ester bond of the compound (3) can be mentioned. ^{R f (COOCFR 1 R 2)} n ··· Equation (3) provided that the symbols in the formula have the following meanings. R ^f , n: same meaning as above. R ¹ and R ² : each independently a fluorine atom or a monovalent organic group.

In the present invention, the compound (1) is reacted with a brominating agent. The brominating agent may be a compound which itself becomes a brominating agent or a compound which can be converted into a brominating agent in the reaction system. Examples of the brominating agent include bromine (Br ₂ ), hydrobromic acid, potassium bromide, trimethylsilylbromine, BrF, BrF ₃ , BrF ₅ , B.
rCl, BrCl _{3 and the} like, bromine, BrF, Br
F ₃ , BrCl, BrCl _{3 and the} like are preferable, and bromine is particularly preferable.

The amount of the brominating agent is, based on the compound (1),
(1 × n) -fold mole to (50 × n) -fold mole is preferable, and (1 × n) -fold mole to (10 × n) -fold mole is particularly preferable in view of problems such as post-treatment. Here, n corresponds to n in the compound (1).

The reaction may be carried out without solvent or in the presence of a solvent. When a solvent is used, one or two or more kinds of solvents that are inert in the reaction can be used. Examples of the solvent include hydrocarbon solvents such as cyclohexane and n-hexane, halogenated hydrocarbon solvents such as dichloromethane, dichloroethane, carbon tetrachloride and chloroform, diethyl ether, diisopropyl ether, methyl-te.
An ether solvent such as rt-butyl ether, ethylene glycol dimethyl ether, tetrahydrofuran or dioxane, or a nitrile solvent such as acetonitrile is used.

When a solvent is used, the amount is 0.5 to 2 with respect to 1 g of the compound (1) for reasons such as ease of post-treatment.
00 mL is preferable, and 1 to 50 mL is particularly preferable.

The reaction of the present invention is preferably carried out as a gas phase reaction or a liquid phase reaction. The reaction pressure may be under reduced pressure, atmospheric pressure, or increased pressure. Further, the reaction of the present invention can be carried out in either a batch system or a continuous system. Moreover, the reaction apparatus for carrying out the reaction of the present invention is not particularly limited, and it is usually preferable to use a reaction apparatus made of stainless steel or Hastelloy.

The reaction time of the reaction of the present invention is the same as that of the compound (1).
Can be appropriately changed depending on the structure of
1 hour is preferable, and in the liquid phase reaction, 30 minutes to 72 hours is preferable. The reaction temperature is also appropriately changed depending on the structure of the compound (1) and is preferably -100 ° C to 500 ° C. When it is desired to carry out the reaction of the present invention at a high reaction temperature, it is preferably carried out in a gas phase reaction, and particularly preferably carried out in a gas phase reaction using bromine gas as a brominating agent.

The lower limit of the reaction temperature in the gas phase reaction is not less than the boiling point of the compound (1), and the reaction temperature in the usual gas phase reaction is preferably from the boiling point of the compound (1) to 500 ° C.
250 ° C to 450 ° C is particularly preferable.

When the gas phase method is used, an inert gas which does not react with the compound (1) or the brominating agent (for example,
Examples thereof include nitrogen gas, helium gas, argon gas and carbon dioxide gas. ) May coexist in the reaction system.
The amount of the inert gas is preferably 0.01 times mol to 100 times mol, and particularly preferably 0.1 times mol to 10 times mol, with respect to the total molar amount of the compound (1) and the brominating agent.

The reaction of the present invention may be carried out in the presence of a catalyst, and it is preferable to carry out the reaction in the presence of at least one inorganic catalyst. As the inorganic catalyst, aluminum oxide, vanadium oxide, silica, diatomaceous earth, alumina, titanium oxide, pumice powder, pumice stone balloon, aluminum hydroxide, magnesium hydroxide, sodium hydroxide, potassium hydroxide, potassium carbonate, calcium carbonate ,sodium carbonate,
Rubidium carbonate, cesium carbonate, cesium oxide, magnesium oxide, barium carbonate, basic magnesium carbonate,
Strontium carbonate, trivalent antimony bromide, pentavalent antimony bromide, trivalent aluminum bromide, trivalent chromium bromide, monovalent silver bromide, monovalent mercury bromide, divalent mercury bromide, divalent calcium bromide , Trivalent boron bromide, trivalent arsenic bromide, divalent magnesium bromide, divalent beryllium bromide, pentavalent niobium bromide, pentavalent thallium bromide, trivalent rubidium bromide, tetravalent tin bromide, odor Tetravalent titanium, dolomite, calcium sulfate, potassium titanate, barium sulfate, calcium sulfite, talc,
Clay, mica, asbestos, glass fiber, glass flakes, glass beads, calcium silicate, montmorillonite, bentonite, graphite, aluminum powder,
Molybdenum sulfide and the like are preferable.

Of these, as the inorganic catalyst, silica, alumina, magnesium oxide, aluminum hydroxide, magnesium hydroxide, since the compound (1) can be efficiently adsorbed and activated and the reaction of the present invention can be carried out smoothly, Particularly preferred are magnesium carbonate, sodium carbonate, potassium carbonate, glass fibers, glass flakes, glass beads or calcium silicate.

When the reaction of the present invention is carried out in the presence of a catalyst, the shape of the packed bed in the reactor is not particularly limited,
It is preferably a fixed bed, a moving bed, a fluidized bed or the like.

In the reaction of the present invention, --CO of compound (1) is used.
The F group is substituted with a bromine atom to produce the compound (2).
The crude product produced by the bromination reaction is preferably subjected to usual post-treatment to obtain the compound (2). Moreover, you may refine | purify according to the objective. At this time, since the compound (2) produced by the method of the present invention does not contain an iodine compound that is difficult to remove as an impurity, the purification method may be distillation, recrystallization, column chromatography, or a combination thereof. By carrying out, a compound (2) having sufficiently high purity can be obtained.

R ^f and n of the product, compound (2)
Is the same as the compound (1). The compound (2) is preferably the compound (2-1) produced when the compound (1-1) is used as the compound (1). R ^f1- Br ... Formula (2-1) However, R ^f1 shows the same meaning as the above. The compound (2) is useful as a synthetic intermediate, a halon-based extinguishing agent, a flame retardant additive for trans oil or electric insulating oil, an X-ray contrast agent, and the like.

[0031]

EXAMPLES The present invention will be described in detail below with reference to examples.
However, the present invention is not limited thereto. [Example 1] CF_Three(CF_Two)_TwoOCF (CF_Three) CF_TwoO
CF (CF_Three) Example of Br production On one side of a U-shaped reaction tube having a length of 1.6 cm and a length of 120 cm,
Fill glass beads (50 ml) as a catalyst and salt bath
Was used to raise the temperature to 330 ° C. CF in the reaction tube _Three(CF
_Two)_TwoOCF (CF_Three) CF_TwoOCF (CF_Three) COF
(Hereinafter referred to as compound (1-2)), bromine gas and nitrogen
The gas and the gas were supplied at a ratio of 1: 3: 6 (molar ratio), respectively.
The feed rate is 16 g / h as the rate of the compound (1-2)
I adjusted. Attach an ice trap to the U-tube outlet
Was recovered. The recovered solution is an aqueous sodium thiosulfate solution.
Washed with. Collect the lower layer solution after washing and perform GC analysis.
As a result, the title compound had a conversion rate of 98.8% and a selectivity of 4
It was produced at 3.3%. In addition, the selectivity in the solution is 3
At 8.1% (CF_Two)_TwoOCF (CF_Three) CF_TwoOCF
(CF_TwoBr) Br was included.

[0032] [Example _{2] CF 3 (CF 2)} 7 Br preparing the same reactor as in Preparation Examples Example 1, the reaction tube _CF 3 (CF
₂ ) ₇ COF (hereinafter, referred to as compound (1-3)), bromine gas and nitrogen gas are mixed in a ratio of 1: 4: 5 (molar ratio).
Supplied by. The supply rate was adjusted to 8.0 g / h as the rate of the compound (1-3). The solution collected at the U-tube outlet was washed with an aqueous sodium thiosulfate solution. The lower layer solution after washing was collected and analyzed by GC. As a result, the title compound was found to be produced at a conversion rate of 99.8% and a selectivity of 75.7%. Further, in the solution, the selectivity of CF ₃ (C
F _{2) 5} CFBrCF ₂ Br have been included.

[0033]

EFFECTS OF THE INVENTION According to the method of the present invention, synthetic intermediates, perfluoroorganic bromides useful as halon-based extinguishing agents, flame-retardant additives for trans oils and electric insulating oils, X-ray contrast agents, etc. The compound (1), which can be obtained as described above, can be obtained in a high yield by a simple operation. The method of the present invention is a method that can simplify the purification step and does not use a special device or a special reagent, and thus is a very useful method as an industrial process.

Claims (6)

[Claims] 1. A process for producing a perfluoroorganic bromide represented by the formula (2), which comprises reacting a compound represented by the following formula (1) with a brominating agent. R ^f (COF) _n ··· Formula (1) R ^f Br _n ··· (2) However, the symbols in the formula have the following meanings. R ^f : Perfluoro n-valent organic group. n: An integer of 1 to 4. 2. The production method according to claim 1, wherein the compound represented by the formula (1) and the brominating agent are reacted in a gas phase. 3. The method according to claim 1, wherein the reaction is carried out in the presence of at least one inorganic catalyst. 4. An R ^f group is a perfluoroalkyl group and n
Is 1. The manufacturing method according to any one of claims 1 to 3. 5. The brominating agent is Br ₂ . The manufacturing method according to claim 1. 6. A compound represented by the formula (1) is represented by the following formula (3):
The method according to any one of claims 1 to 5, which is a compound obtained by decomposing the ester bond of the compound represented by. R ^f (COOCFR ¹ R ² ) _n ··· Formula (3) However, R ^f and n in the formula have the same meanings as described above,
R ¹ and R ² each independently represent a fluorine atom or a monovalent organic group.