JP2001192346A - Method for producing perfluoroalkadiene - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a method safe and suitable for industrial practice for efficiently producing a perfluoroalkadiene. SOLUTION: This method for producing a perfluoroalkadiene comprises the following process: an α,ω-dihalogenoperfluoroalkane of the formula: XCF2 CF2-(CF2CF2)a[CF2CF(CF3)]b-CF2-CF2X wherein, (a) and b are each an integer of 0-2; and X is I or Br, is heated or subjected to boiling reflux in an organic solvent together with at least one metal selected from Mg, Zn, Cd, Al, Cu, Na and Li and 0.05-0.5 equivalent, based on the α,ω-dihalogenoperfluoroalkane, of an alkyl halide of the formula: RX (X is Cl, Br or I; and R is a staright- chain, branched or cyclic alkyl or aryl group).

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing .alpha.,. Omega.-perfluoroalkadiene which can be used, for example, as a raw material of a polymer for a coating or as an etching gas for a semiconductor.

[0002]

2. Description of the Related Art As a method for synthesizing an α, ω-perfluoroalkadiene, the most typical method, a compound having 4 carbon atoms, perfluorobutadiene, has long been studied.

[0003] For example, R. N. Haszeldine:
J. Chem. Soc. , 4423 (1952)
CCIF = CF ₂ and CC
1F ₂ -CClFI was obtained, and subsequently, CClF ₂ -CCIF-CCLF-CCIF ₂ was synthesized by a photoreaction in the presence of Hg, and this was treated with zinc in ethanol to obtain CF ₂ = CF-CF = CF. How to get ₂ has been reported. However, this method has many problems and has problems such as the use of environmentally unfriendly raw materials such as mercury.

[0004] Further, R. N. Haszeldine,
J. Chem. Soc. , 4026 (1954), CF ₂ = by pyrolysis of perfluoroadipate.
We have reported the synthesis of CF-CF = CF _2. However, this reaction is not preferable as an industrial production method such as a low yield and a large amount of isomers.

[0005] W. T. US Patent No. by Miller
No. 2,668,182, CCIF = CF_TwoTo
Reacts with raw materials in Pyrex tube at 550 ° C
And CF_Two= CF-CCLF-CCLF_TwoGet this
Chlorinated or brominated, and_Two-C
ClF-CCLF-CCLF_TwoOr CBrF_Two-CBr
F-CCIF-CCIF_TwoAfter the conversion to J. Che
m. Soc. , 4423 (1952).
Carry out dehalogenation reaction with lead, CF_Two= CF-C
F = CF_TwoIs what you get. In this reaction, the first stage C
F_Two= CF-CCLF-CCLF _TwoReaction yield is low
Is also industrially suitable
It's hard to say how.

G. Bargigia, V .; Torte
lli, C.I. Tonelli, S .; E. Mondena et al., European Patent Application 0 270 956, JP-A-62-26240 by the same group, et al. S. El
izabath: J. Org. Chem. , 36 (19
71) 364 and the like, XCF ₂ -CF ₂ X obtained by adding iodine or bromine to CF ₂ ＣＦCF ₂ as a raw material.
XCF ₂ —CF ₂ —CF ₂ —CF ₂ X produced by the telomerization reaction of (X = I, Br) is converted from −80 ° C. to +
Mg, Z in an aprotic organic solvent at 150 ° C
n, reaction for obtaining a _{CF 2 = CF-CF = CF} 2 has been reported by the reaction of an organometallic compound of Cd or Li. In this method, the raw material XCF ₂ —CF ₂
-CF ₂ -CF ₂ X can be obtained, and it cannot be said that this method is relatively easy to industrialize. However, in the dehalogenation reaction, a large amount of a highly active organometallic compound is required, so that it is still not suitable for industrialization.

[0007] This is because the organometallic compound has the following problems. Being sensitive to moisture requires special care to avoid hydrolysis. Organometallic compounds involve considerable danger during production.For example, when synthesizing Grignard reagents, if the reaction is improperly controlled such as when cooling is insufficient, the reaction often runs away and explosively proceeds. Can be The organometallic compound is an extremely active compound that easily reacts with moisture, oxygen and the like, so it is difficult to store and use it in large quantities, and it is considered that industrial handling is dangerous in terms of storage. Organometallic compounds are quite expensive for the above reasons, and their use in large quantities industrially is considered to be disadvantageous in terms of cost.

[0008]

SUMMARY OF THE INVENTION In view of the above-mentioned drawbacks of the prior art, the present invention provides a method for producing perfluoroalkadienes that is safe and suitable for industrial practice with these drawbacks reduced or eliminated. Its primary purpose is to provide.

Thus, according to the present invention, an alkyl halide is used as a catalyst in a reaction system without using an organometallic compound, and the metal and XCF ₂ —CF ₂ —CF ₂ —CF ₂ X
(X = I, Br) is provided. That is, if Mg is taken as an example in the present invention, it is not necessary to directly handle dangerous organometallic compounds by separately adding a catalytic amount of alkyl halide and Mg to the reaction system, and even if water is mixed in, the reaction system becomes nitrogen. It can be prevented just by sealing. Therefore, handling of the reagent itself is very easy. In this method, a reaction between a small-scale catalyst and a dehalogenating agent in a large amount of a solvent (1/1 of the Grignard reaction) is performed.
(A scale of 2 to 1/20), the reaction is mild and safe. Further, storage problems can be solved by using a metal having relatively low activity and an alkyl halide separately. Since the amount of the alkyl halide used can be reduced to 1/2 to 1/20, this is also advantageous in cost.

It is another object of the present invention to provide a method capable of industrially producing inexpensive α, ω-perfluoroalkadiene.

[0011]

SUMMARY OF THE INVENTION The present invention has been made to solve the above-mentioned problems. That is, commercially available α, ω-diiodine or dibromoperfluoroalkane can be prepared by heating Mg, Zn, Cd in an organic solvent such as tetrahydrofuran in the range of -70 ° C to + 200 ° C in the presence of an appropriate amount of an alkyl halide as a catalyst. , Al, Cu, Na
Or by reacting with a metal such as Li to remove IF or B
α, ω-Perfluoroalkadiene is obtained in high yield by performing rF. Since it has high hygroscopicity, easily decomposes, and does not use expensive organometallic compounds, it is an inexpensive and industrially suitable production method and can also improve workability and safety.

The compound intended in the present invention has the following general formula (1) having double bonds at both ends of a carbon chain: CF ₂ ＝ CF— (CF ₂ CF ₂ ) _a (CF ₂ CF (CF ₃₎ )) _B -CF = CF ₂ (1) wherein a and b are integers of 0 to 2 and may be the same or different.

The α, ω-dihalogenated perfluoroalkane used as a raw material for the reaction is represented by the following formula (2): XCF ₂ CF _2- (CF ₂ CF ₂ ) _a (CF ₂ CF (CF ₃ )) _b- CF ₂ -CF ₂ X (2) (wherein, a and b are as defined above, and X at both ends is iodine or bromine.)

The alkyl halide used as the catalyst is represented by the general formula (3): RX (3), wherein X is any of chlorine, bromine and iodine, and R is a linear, branched or cyclic one. It is selected from compounds represented by an alkyl group or an aryl group. The amount of the alkyl halide (3) used as the catalyst depends on the amount of α,
It is in the range of 0.05 equivalent to 0.5 equivalent based on the ω-dihalogenated perfluoroalkane (2).

Further, as an activator for the reaction, a compound of the general formula XR-
Alkyl dihalide represented by X (R represents a carbon number of 1 to 7)
Is selected from the compounds represented by linear, branched, or cyclic alkyl groups) and / or iodine, etc., in order to start the reaction easily, which is more preferable.

The metals used in the reaction include Mg, Z
n, Cd, Al, Cu, Na or Li is desirable. These metals are used alone or in combination of two or more. As the shape, a cut piece, a lump, or a powder can be used, and the size can be appropriately selected. The amount used is equal to or more than the equivalent, but from the viewpoint of reaction efficiency and cost, 1.
About 0 to 5 equivalents are preferred.

Solvents that can be used to carry out the reaction include linear or branched, cyclic ethers such as tetrahydrofuran, dioxane, ethyl ether and isopropyl ether, polyethers such as dimethoxyethane and 2-methoxyethyl ether, and hexane. , Octane, nonane, hydrocarbons such as petroleum ether, ethyl acetate, methyl acetate, esters such as ethyl propionate, phosphates such as triethyl phosphonate, linear and cyclic carbonates such as diethyl carbonate or ethylene carbonate, Alkyl or aryl nitriles such as acetonitrile and benzonitrile; ketones such as acetone and methyl ethyl ketone; acid anhydrides such as acetic anhydride; amides such as N, N'-dimethylformamide (DMF) and N, N'-dimethylacetamide , Dimethyl sulfoxide (DMS
Sulfoxides such as O), aliphatic or aromatic nitro compounds such as nitroethane or nitrobenzene,
Examples include nitrogen-containing heterocyclic compounds such as pyridine and piperidine, sulfone compounds such as dimethyl sulfone and phenyl sulfone, and dialkyl or diaryl sulfides such as diethyl sulfide and diphenyl sulfide.

The reaction temperature is desirably in the range of -70 ° C to + 200 ° C. By performing heating or boiling reflux together with the metal and the alkyl halide in the above organic solvent, the perfluoroalkadienes of the formula (1) from the above formula (2) are produced.

The amount of the solvent used is such that the α, ω-dihalogenated perfluoroalkane (2) as a raw material for the reaction is 0.1 M to 2 M, preferably 0.2 M to 1.0 M during the reaction.
It is preferable to adjust so as to be as follows, but it is not limited to this range depending on the kind of the raw material. The α, ω-dihalogenated perfluoroalkane used as a starting material for the reaction is desirably diluted with the same solvent as described above.

Hereinafter, the present invention will be further described with reference to typical reaction examples of the present invention, but the present invention is not limited thereto.

[0021]

Embodiment 1 A 100 equipped with a reflux cooling pipe connected to a trap pipe cooled to -78 ° C. and a dropping funnel equipped with a pressure balance pipe.
In a 3-mL three-necked flask, under a nitrogen atmosphere, 1.2 equivalents of M
g, 20 mL of tetrahydrofuran, 0.1 mL of 1,2-dibromoethane, and 0.2 equivalent of bromoethane as a catalyst were further added. The solution was heated to reflux, to which 5 m
5.0 g of 1,4-diluted with L of tetrahydrofuran
Diiodoperfluorobutane was added slowly so that the foaming was not too vigorous. The generated gas was collected by a trap tube at -78 ° C. After the completion of the dropwise addition, boiling reflux was continued to drive off CF ₂ = CF-CF = CF ₂ remaining in the reaction solvent. When the liquid collected in the trap tube was analyzed by gas chromatography, CF ₂ = CF-CF
= CF ₂ was generated 1.57 g (yield: 88%).

[0022]

Example 2 100 equipped with a reflux cooling pipe connected to a trap pipe cooled to -78 ° C and a dropping funnel equipped with a pressure balance pipe.
In a 3-mL three-necked flask, under a nitrogen atmosphere, 1.2 equivalents of M
g, 40 mL of tetrahydrofuran, 0.1 mL of 1,2-dibromoethane, and 0.3 equivalent of isopropyl bromide as a catalyst were further added. The solution was heated to reflux and 5.0 g diluted with 10 mL of tetrahydrofuran.
Of 1,4-dibromoperfluorobutane was added slowly so that the foaming was not too intense. The generated gas is -7
It was collected in a trap tube at 8 ° C. Continued to boiling under reflux after completion of the dropwise addition, remaining in the reaction solution _{CF 2 = CF-CF = CF} 2
Kicked out. When the liquid collected in the trap tube was analyzed by gas chromatography, CF ₂ =
CF-CF = CF ₂ was generated 1.91 g (yield;
85%).

[0023]

Example 3 A 100 mL three-necked flask equipped with a distillation apparatus with a biclaw tube connected to a trap tube cooled to −78 ° C. and a dropping funnel with a pressure balance tube was placed under a nitrogen atmosphere.
1.2 equivalents of Mg and 50 mL of tetrahydrofuran, 1,
0.1 mL of 2-dibromoethane and 0.1 equivalent of 1-bromopropane as a catalyst were further added. The solution was heated to reflux, and to this was added slowly 5.0 g of 1,6-diiodoperfluorohexane diluted with 10 mL of tetrahydrofuran so as not to foam too vigorously. The reaction product is distilled together with the solvent through a distillation apparatus. After the completion of the dropwise addition, boiling reflux was continued, and the product remaining in the reaction solution was distilled off together with the solvent through the distillation apparatus. When the liquid collected in the trap tube was analyzed by gas chromatography, CF ₂ = CF—CF ₂ —CF ₂ —CF
= CF ₂ was generated 1.85 g (yield: 78%).

[0024]

Example 4 100 m provided with a reflux cooling pipe connected to a trap pipe cooled at -78 ° C. and a dropping funnel with a pressure balance pipe.
The L three-necked flask was cooled to -70 ° C under a nitrogen atmosphere, and 30 mL of anhydrous hexane, 1.5 equivalents of Li, and 0.2 equivalents of 1-bromobutane as a catalyst were added. The solution was heated to reflux and to this was added slowly 5.0 g of 1,4-diiodoperfluorobutane diluted with 5 mL of anhydrous hexane so as to avoid excessive bubbling. The generated gas was collected by a trap tube at -78 ° C. After completion of the dropwise addition, the mixture was further refluxed by boiling to drive off CF ₂ = CF-CF = CF ₂ remaining in the reaction solvent. When the liquid collected in the trap tube was analyzed by gas chromatography, CF ₂ = CF-CF = CF ₂ was 1.42.
g (yield; 80%).

[0025]

Example 5 100 equipped with a reflux cooling pipe connected to a trap pipe cooled to -78 ° C and a dropping funnel equipped with a pressure balance pipe.
A 3-mL three-necked flask was cooled to -70 ° C under a nitrogen atmosphere, and 40 mL of anhydrous hexane and 1.5 equivalents of Na were added. The solution was heated to reflux, and 5.0 g of 1,4-diiodoperfluorobutane diluted with 5 mL of anhydrous hexane and 0.2 equivalent of 1-bromobutane were slowly added to the solution so that the foaming was not excessive. added. The generated gas was collected by a trap tube at -78 ° C. After completion of the dropwise addition, the mixture is further refluxed by boiling, and CF ₂ ＣC remaining in the reaction solvent
F-CF = CF ₂ was driven out. The liquid is collected in a trap tube was analyzed by gas _{chromatography, CF 2 = CF-CF =} CF 2 was generated 1.10 g (yield: 62%).

[0026]

Embodiment 6 In Embodiment 1, Zn-Cu is used instead of Mg.
(Combination of 95: 5) in the same manner except that
5.0 g of 1,4-diiodoperfluorobutane was added, and the mixture was refluxed by boiling. When the liquid collected in the trap tube was analyzed by gas chromatography,
_{CF 2 = CF-CF = CF} 2 had 1.50g produced (yield: 84%).

[0027]

Comparative Example 1 A 200 equipped with a reflux cooling pipe connected to a trap pipe cooled to -78 ° C. and a dropping funnel equipped with a pressure balance pipe.
In a nitrogen three-necked flask, 1.5 mL of M
g, 40 mL of tetrahydrofuran, 0.1 mL of 1,2-dibromoethane, and 0.02 of bromoethane as a catalyst.
Added equivalent. The solution is heated to reflux and
10.0 g of 1.4-diiodoperfluorobutane diluted with 0 mL of tetrahydrofuran was added over 30 minutes. The generated gas was collected by a trap tube at -78 ° C. After the completion of the dropwise addition, boiling reflux was continued to drive off CF ₂ = CF-CF = CF ₂ remaining in the reaction solvent. When the gas in the gas phase was analyzed by gas chromatography, slight production of the desired CF ₂ = CF-CF = CF ₂ was recognized, but almost no liquid was collected in the trap tube.

 ──────────────────────────────────────────────────の Continued on the front page (72) Inventor Hiroshi Arakawa 1497, Shibukawa-shi, Gunma Kanto Denka Kogyo Co., Ltd.Shibukawa Plant (72) Inventor Koji Shimada 1497 Shibukawa-shi, Gunma Kanto Denka Kogyo Co., Ltd. (72) Inventor Toshihiko Ishii 1497 Shibukawa-shi, Gunma Kanto Denka Kogyo Co., Ltd.

Claims (3)

[Claims] 1. The following general formula (1) having double bonds at both ends of a carbon chain: CF ₂ CF— (CF ₂ CF ₂ ) _a (CF ₂ CF (CF ₃ )) _b —CF = CF ₂ (1) In the method for producing perfluoroalkadienes represented by the formula (2), wherein a and b are integers of 0 to 2 and may be the same or different, XCF ₂ CF: _{2 - (CF 2 CF 2)} a (CF 2 CF (CF 3)) b -CF 2 -CF 2 X (2) ( in formula, a and b are as defined above, X at both ends or iodine Α, ω-dihalogenated perfluoroalkane represented by the formula: Mg, Z in an organic solvent.
n, Cd, at least one metal selected from Al, Cu, Na and Li, and 0.05 to 0.5 equivalents of the following formula (3) with respect to the α, ω-dihalogenated perfluoroalkane. ): RX (3) (wherein X is any of chlorine, bromine and iodine;
Represents a linear, branched or cyclic alkyl or aryl group. (1) wherein the compound is subjected to heating or boiling reflux together with the alkyl halide represented by the formula (1).
A method for producing perfluoroalkadienes of the formula 2. An activator having the general formula: X—R—X (R
Is a linear, branched or cyclic alkyl group having 1 to 7 carbon atoms, and X is any one of chlorine, bromine and iodine. 2. The process according to claim 1, wherein an alkyl dihalide and / or iodine is present. 3. The method according to claim 1, wherein the reaction is carried out under a dry or anhydrous atmosphere.