JP2000080051A - Preparation of 1,1,9,9-tetrabromo-[2,2]-paracyclophane - Google Patents

Abstract

PROBLEM TO BE SOLVED: To effectively obtain 1,1,9,9-tetrabromo-[2,2]-paracyclophane in a short time without using carbon tetrachloride as the solvent which is difficult to use in an industrial scale by carrying out the bromination of a specific paracyclophane with bromine in the presence of a radical initiator using tetrachloroethylene as the reaction solvent. SOLUTION: The objective compound of formula II is obtained by brominating the [2,2]-paracyclophane of formula I by bromine using preferably 15 to 20 times of tetrachloroethylene as the reaction solvent in the presence of the radical initiator (e.g.; benzoyl peroxide). The sequential addition of the radical initiator and the bromine is preferred. The preferred reaction temperature is 110 deg.C to the refluxing temperature. The preferred amount of the bromine is 4.8 to 6.5 moles per 1 mole of the compound of formula I. After the reaction, hydrogen bromide and the bromine is removed by decompression under cooling or blowing nitrogen. Further cooling, filtering and washing affords the objective compound.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a compound represented by the following structural formula (II) used for forming a coating film by chemical vapor deposition:
I)

[0002]

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[0003] 1,1,9,9-Tetrabromo- [2,2] which is an intermediate for producing 1,1,9,9-tetrafluoro- [2,2] -paracyclophane represented by ]
It relates to a process for producing paracyclophane.

[0004]

2. Description of the Related Art 1,1,9,9-Tetrafluoro-
[2,2] -Paracyclophane forms a poly-α, α-difluoroparaxylylene film on a substrate by the following reaction by a chemical vapor deposition method.

[0005]

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This coating film has the following structural formula (IV) which has been widely used for coating aerospace equipment and electronic parts.

[0007]

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Has much better heat resistance in air than polyparaxylylene film represented by (JP-A-9-25252) As a method for producing this 1,1,9,9-tetrafluoro- [2,2] -paracyclophane, the following synthesis method was studied.

[0009]

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[0010]

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However, due to the reaction specificity of the paracyclophane ring and the fluorine atom, only the synthetic route of the above (A) can be
1,9,9-Tetrafluoro- [2,2] -paracyclophane has not been obtained. 1,1,9,9-Tetrabromo- [2,2] -paracyclophane (Structural Formula II), which is an intermediate in this route, is synthesized in a carbon tetrachloride solvent under the presence of peroxide and ultraviolet irradiation. [2,2] -Paracyclophane (Structural Formula I) is reacted with N-bromosuccinimide (N
BS). [2,2]-
In the bromination reaction of paracyclophane with NBS, favorable results have not been obtained except for a carbon tetrachloride solvent. For example, benzene, chloroform, 1,2-dichloroethane,
1,1,2-trichloroethane, trichloroethylene,
Tetrachloroethylene, chlorobenzene, o-dichlorobenzene, p-dichlorobenzene, dibromomethane, tetrabromomethane, 1,4-bis (trifluoromethyl) benzene, N, N-dimethylformamide, N, N
Even if -dimethylacetamide, N-methylpyrrolidone, dimethylformamide and sulfolane are used in place of carbon tetrachloride and reacted under the same reaction conditions, the desired result is not obtained. In a polar solvent such as N, N-dimethylformamide or sulfolane, the nuclear substitution reaction takes precedence, and in a non-polar solvent such as tetrachloroethylene for a long time, NB is used.
The transformation of S occurs, and the reactants turn black. The same applies to the case where 1,3-dibromo-5,5-dimethylhydantoin is used as a brominating agent.

[0012]

SUMMARY OF THE INVENTION In a carbon tetrachloride solvent,
By reacting NBS with [2,2] -paracyclophane, 1,1,9,9-tetrabromo- [2,2] -paracyclophane can be obtained. In this case, the following problems occur. There is. (1) The production of carbon tetrachloride has been discontinued as an ozone-depleting substance and cannot be used industrially. (2) Since a long reaction time of 50 hours is required in the presence of peroxide and irradiation with ultraviolet rays, it is extremely disadvantageous in terms of production efficiency and economy.

Accordingly, the present invention provides a method for efficiently using 1,1,9,9-tetrabromo- [2,3 in a short time without using carbon tetrachloride which is difficult to industrially use as a solvent.
2] -To provide a method for producing paracyclophane.

[0014]

As a result of various studies, the present inventor has found that the efficiency can be improved by brominating [2,2] -paracyclophane with bromine using tetrachloroethylene as a reaction solvent in the presence of a radical generator. Well, 1,1,9,9-
The inventors have found that tetrabromo- [2,2] -paracyclophane can be obtained, and have completed the present invention.

[0015]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, the present invention will be described in detail. The present invention brominates [2,2] -paracyclophane with bromine in the presence of a radical generator using tetrachloroethylene as a solvent. The amount of tetrachloroethylene used as a solvent depends on the amount of [2,2] -paracyclophane as a starting material and 1,1,9,9-tetrabromo- [2,2] -paracyclophane as a product to tetrachloroethylene. Considering the solubility, it is preferable to use about 15 to 20 times the weight ratio of [2,2] -paracyclophane.

The radical generator used in the present invention is not particularly limited, and azo compounds such as 2,2'-azobisisobutyronitrile and peroxides such as benzoyl peroxide are generally used. Any of these can be used. As a suitable radical generator, for example, Nippon Oil & Fats Co., Ltd., trade name "Niper FF"
And benzoyl peroxide sold under the trade name. "Niper FF" dilutes benzoyl peroxide with a special diluent to increase the safety in handling.
% Product, and is suitably used in terms of solubility in solvents and safety. These radical generators
It is necessary to heat a tetrachloroethylene solution of [2,2] -paracyclophane to a predetermined temperature and add it to the reaction system together with bromine under stirring. Although the method of addition is not particularly specified, it is generally dissolved in tetrachloroethylene and added sequentially (usually dropwise) with bromine. The dropping may be performed in the whole process of the bromine dropping, or may be performed in a part of the initial stage of the bromine dropping. The radical generator cannot be added to the reaction system from the beginning. If the radical generator is added to the reaction system from the beginning, rapid decomposition occurs when the temperature is raised, which is dangerous, and the generated radicals do not act effectively on the reaction. The amount of the radical generator used naturally changes depending on the type of the radical generator, but in the case of “Nipper FF”, 2% (based on [2,2] -paracyclophane in terms of benzoyl peroxide) % By weight). If the amount is larger than this, the reaction is not hindered. However, if the amount is too small, the reaction is not completed and the yield is reduced, and a large amount of bromine adduct to tetrachloroethylene is produced.

In the present invention, bromine is used as the brominating agent. It is preferable that bromine be added (usually dropwise) together with the radical generator in the course of the reaction. Bromine can be added dropwise as it is, or may be diluted with tetrachloroethylene and added dropwise. However, when tetrachloroethylene and bromine are mixed, 1,2-dibromotetrachloroethane, which is an adduct of bromine to tetrachloroethylene, is produced. Therefore, when the reaction amount is large, it is preferable to add dropwise without dilution. The amount of bromine used is preferably about 4.8 mol to 6.5 mol with respect to 1 mol of [2,2] -paracyclophane in consideration of addition to a part of the solvent. When the amount of bromine used is too small, dibromo and tribromo forms are produced due to incomplete bromination, and the yield is reduced. Conversely, when the amount of bromine used is excessive, the bromine adduct of tetrachloroethylene increases, but other by-products do not increase much. In the present invention, the radical generator and the bromine can be dropped as the same solution, but it is desirable to drop them separately from the viewpoint of safety from an industrial viewpoint.

The reaction temperature in the present invention is preferably from 110 ° C. to the reflux temperature (preferably the reflux temperature). At a temperature lower than this, the desired reaction does not proceed, and the desired compound cannot be obtained. In the reaction, after dropping the radical generator and the brominating agent at a predetermined reaction temperature, stirring and reacting for a while, the bromine color of the solution almost disappears. The reaction time naturally depends on conditions such as the reaction amount,
In the following example scale, it is about 2 hours, which is about 1/25 of the reaction time when carbon tetrachloride is used as a solvent. The reaction is terminated when the bromine color has almost disappeared. After completion of the reaction, hydrogen bromide and bromine in the reaction solution are removed as much as possible by cooling or by blowing nitrogen under cooling. The reaction solution is further cooled, and the resulting precipitate is collected by filtration and washed with ether and then with methylene chloride. After washing with methylene chloride, 1,1,10,10-tetrabromo-
By-products such as [2,2] -paracyclophane are removed. After washing, it is dried by a conventional method, and has a decomposition temperature of 222 to 22.
A product in the range of 7 ° C is a product. 1,1,10,10-
The incorporation of tetrabromo- [2,2] -paracyclophane lowers the decomposition temperature of the target compound, but proceeds to the ketone reaction in the next step while these impurities remain, and removes unnecessary substances at that stage. It is also possible.

[0019]

Next, the present invention will be further described with reference to examples, but these examples do not limit the present invention. (Example 1) 200 g of tetrachloroethylene was added to [2,
2] -Paracyclophane (12.0 g) was added, and the mixture was heated and refluxed with stirring. Under stirring and reflux, bromine (49.0 g), Niper FF (3.0 g) and tetrachloroethylene (5
0 g) was added dropwise over 2 hours. After the addition, the mixture was stirred and refluxed for another 15 minutes, and then, while cooling, suctioned to remove as much hydrogen bromide and bromine as possible, and further cooled to 10 ° C. The deposited precipitate was collected by filtration and washed with 200 ml of ether. After drying the precipitate, the precipitate was suspended in 340 g of a methylene chloride solvent, and the solution was heated to reflux.
C. and the precipitate was collected by filtration and dried. The obtained 1,
The yield of 1,9,9-tetrabromo- [2,2] -paracyclophane was 7.7 g, the yield was 25.3%, and the decomposition temperature was 224 to 227 ° C.

Example 2 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane was added to g, and the mixture was heated and refluxed with stirring. Stir bromine (50.5) under reflux.
g) and a solution of Niper FF (3.0 g) in tetrachloroethylene (50 g) were added dropwise over 1 hour and 30 minutes while maintaining the balance between the amounts of both added. After dropping, add 15 more
After stirring and refluxing for minutes, the same treatment as in Example 1 was performed.
The obtained 1,1,9,9-tetrabromo- [2,2]-
The yield of paracyclophane is 7.4 g, and the yield is 24.4%.
And the decomposition temperature was 224 to 227 ° C.

Example 3 Tetrachloroethylene 200
g, then add 12.0 g of [2,2] -paracyclophane,
The mixture was heated and refluxed with stirring. Stir bromine under reflux (53.
A solution of 5 g) in tetrachloroethylene (42 g) and a solution of azobisisobutyronitrile (1.5 g) in tetrachloroethylene (80 g) (partially insoluble) were added dropwise over 1 hour and 22 minutes while maintaining the balance of the amounts of both added. . After completion of the dropwise addition, the mixture was stirred and refluxed for another 15 minutes, and then treated in the same manner as in Example 1. The yield of the obtained 1,1,9,9-tetrabromo- [2,2] -paracyclophane was 6.8 g, the yield was 22.5%, and the decomposition temperature was 224 to 227 ° C.

Example 4 Tetrachloroethylene 200
g, then add 12.0 g of [2,2] -paracyclophane,
Heat to 110 ° C. with stirring. A solution composed of bromine (53.5 g), nipper FF (3.0 g) and tetrachloroethylene (47.0 g) was added dropwise with stirring and at 110 ° C. over 3 hours and 20 minutes. After the completion of the dropwise addition, the reaction was continued for another 20 minutes. The yield of the obtained 1,1,9,9-tetrabromo- [2,2] -paracyclophane was 6.5 g, the yield was 21.4%, and the decomposition temperature was 222 to 224 ° C.

Example 5 Tetrachloroethylene 200
g, then add 12.0 g of [2,2] -paracyclophane,
Stir, heat and reflux. Stir bromine under reflux (58.5).
g) and a solution of Niper FF (0.4 g) in tetrachloroethylene (20 g) were added dropwise. The dropping was started at the same time, and the dropping of the Niper FF solution was completed in 50 minutes, and the dropping of bromine was completed in 2 hours and 10 minutes. After the completion of the dropwise addition, the reaction was continued for 30 minutes. The obtained 1,1,9,
The yield of 9-tetrabromo- [2,2] -paracyclophane was 7.1 g, the yield was 23.5%, and the decomposition temperature was 222.
２225 ° C.

Reference Example 1 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane and 3.0 g of Niper FF (3.0 g) were added to the resulting mixture, and the mixture was heated and refluxed with stirring.
Under stirring and reflux, a solution composed of bromine (53.4 g) and tetrachloroethylene (52 g) was added dropwise over 3 hours and 25 minutes. After completion of the dropwise addition, the mixture was further stirred and refluxed for 1 hour, and then the same treatment as in Example 1 was tried. However, no precipitate was formed at the stage of cooling the tetrachloroethylene solution.

Reference Example 2 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane and Niper FF (3.0 g) were added to g, and the mixture was heated to 110 ° C with stirring. While stirring and maintaining at 110 ° C., a solution composed of bromine (52.9 g) and tetrachloroethylene (49 g) was added dropwise over 2 hours. After completion of the dropwise addition, the reaction was further continued for 1 hour, and the same treatment as in Example 1 was attempted, but no precipitate was formed.

Reference Example 3 Tetrachloroethylene 200
g, then add 12.0 g of [2,2] -paracyclophane,
Heat to 100 ° C. with stirring. A solution composed of bromine (52.9 g), Niper FF (3.0 g) and tetrachloroethylene (54 g) was stirred for 6 hours while maintaining at 100 ° C. for 3 hours.
After dropping in 0 minutes, the same treatment as in Example 1 was performed. 1g
Was obtained, but the decomposition temperature was as high as 240 to 244 ° C., and the infrared absorption spectrum was different from the intended product.

Reference Example 4 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane was added to g, and the mixture was heated to 100 ° C. with stirring. Niper FF (3.0
When g) was added, the liquid temperature rose to 105 ° C. At this point, a solution consisting of bromine (50.0 g) and tetrachloroethylene (52 g) began to be added dropwise. The reaction temperature was maintained at 100 ° C., and the bromine solution was added dropwise over 4 hours. After the completion of the dropwise addition, the reaction was further continued for 1 hour, and the same treatment as in Example 1 was attempted, but no precipitate was obtained.

Reference Example 5 12.0 g of [2,2] -paracyclophane was added to 200 g of 1,1,2-trichloroethane (boiling point: 114 ° C.), and the mixture was heated to reflux while stirring. Stirring,
Under reflux, bromine (52.7 g) and Niper FF (3.0
g) and a solution consisting of 1,1,2-trichloroethane (54 g) was added dropwise over 2 hours and 15 minutes. After the completion of the dropping, stirring and reflux were continued for another 30 minutes, and then the same treatment as in Example 1 was attempted, but no precipitate was formed at the stage of cooling the 1,1,2-trichloroethane solution.

Reference Example 6 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane was added to the resulting mixture, and the mixture was stirred, heated and refluxed. The bromine (54.0) was stirred and refluxed.
g) and a solution of Niper FF (0.1 g) in tetrachloroethylene (20 g) were added dropwise. The dropping was started at the same time, and the dropping of the Niper FF solution was completed in 45 minutes, and the dropping of bromine was completed in 2 hours and 20 minutes. After the completion of the dropwise addition, the reaction was continued for 30 minutes, and the same treatment as in Example 1 was performed, but the desired product was not obtained.

Reference Example 7 Tetrachloroethylene 200
12.0 g of [2,2] -paracyclophane was added to the resulting mixture, and the mixture was stirred, heated and refluxed. Under stirring and reflux, Niper FF
(0.4 g) in tetrachloroethylene (20 g) was added dropwise over 15 minutes. Immediately after the completion, the dropping of bromine (57 g) was started, and the dropping was completed in 2 hours and 15 minutes. After the completion of the dropwise addition, the reaction was continued for 30 minutes. The obtained target product was 0.1 g or less.

[0031]

According to the present invention, 1,1,1,2 is used without using carbon tetrachloride whose production has been stopped as an ozone depleting substance.
9,9-Tetrabromo- [2,2] -paracyclophane can be efficiently produced in a short time. Also, N-
Since it is not necessary to use an expensive brominating agent such as bromosuccinimide, the production cost can be greatly reduced, and it is of extremely high practical value.

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Claims (3)

[Claims] 1. The following structural formula (I): Wherein the [2,2] -paracyclophane represented by the formula is brominated with bromine in the presence of a radical generator using tetrachloroethylene as a reaction solvent. 1,1,9,9-tetrabromo- [2,2] represented by
-A process for producing paracyclophane. 2. The method for producing 1,1,9,9-tetrabromo- [2,2] -paracyclophane according to claim 1, wherein the radical generator and the bromine are sequentially added. 3. The method according to claim 1, wherein the reaction temperature is from 110 ° C. to the reflux temperature.
A method for producing 9-tetrabromo- [2,22] -paracyclophane.