JP3044829B2 - Method for producing hexabromocyclododecane - Google Patents

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 2,5,6,9,10-hexabromocyclododecane. 1,2,5 obtained by the present invention
6,9,10-Hexabromocyclododecane is a compound useful as a flame retardant for a polymer compound.

[0002]

2. Description of the Related Art 1,2,5,6,9,10-Hexabromocyclododecane (hereinafter abbreviated as HBCD) is a flame retardant used for polystyrene resins and the like. This flame retardant converts bromine into 1,5,9-cis, trans, trans-
It is synthesized by a reaction to be added to cyclododecatriene (hereinafter abbreviated as CDT).

When analyzed using high performance liquid chromatography equipped with an ODS reverse phase column, it is known that HBCD has three types of isomers. They are eluted from the column in the order of α-HBCD, β-HBCD,
γ-HBCD [E. R. Larsen
and E. L. Ecker, J. et al. FireSc
i. , 4,261 (1986)].

The inventors of the present invention have isolated each isomer and measured its physical properties. As a result, the melting points of the α-, β-, and γ-isomers were 184 to 186 ° C, 168 to 171 ° C, and 196 to 196 ° C.
198 ° C. Thermogravimetric analysis (in air, heating rate 1
0 ° C / min), the 5% weight loss on heating is 2
At 42 ° C, 217 ° C and 245 ° C, the 50% weight loss on heating is 255 ° C, 232 ° C and 258 ° C, respectively. Therefore, the thermal stability is higher in the order of γ-HBCD, α-HBCD, and β-HBCD. HBCD used as a flame retardant is γ-
Although the body is mainly used, the quality of HBCD greatly depends on the difference in the abundance ratio of these isomers. For example, when the abundance ratio of β-HBCD having a low melting point and low thermal stability increases, the melting point and heat resistance of HBCD decrease. Therefore, since thermal decomposition of HBCD starts to occur at a relatively low temperature, there have been problems such as corrosion of the molding machine and coloring of the resin.

[0005] The reaction of adding bromine to CDT results in H
Although BCD has been synthesized, various reaction methods such as the following have been disclosed to date.

[0006] German Patent 1 147 574 discloses that bromine is added dropwise to a solution of CDT in ethyl alcohol,
It is described that a bromine addition reaction is performed. However, in this method, an insoluble resinous substance precipitates during the reaction, so that stirring is difficult and scale-up is difficult. Furthermore, the HBCD produced at this time has a drawback that the melting point is low and the heat resistance is inferior.

[0007]

In order to solve the drawback of insoluble resinous substances being precipitated during the reaction, several mixed solvent systems have been disclosed by a similar reaction method. For example, JP-B-49-24474 discloses a mixed solvent system of alcohol and benzene, JP-B-49-24475 discloses a mixed solvent system of alcohol and ester, US Pat. No. 3,833,675 discloses a mixed solvent system of t-butyl alcohol and benzene. No. 5187 discloses a mixed solvent system of alcohol and halogenated hydrocarbon, and EP 181414 discloses a mixed solvent system of alcohol and dioxane. When the reaction is carried out with these solvents, precipitation of resinous substances during the reaction is eliminated because the solubility of the reaction solvent is high. However, problems remain because the HBCD produced has a low melting point and low heat resistance.

Further, Japanese Patent Publication No. 53-12510 discloses a method in which a solvent is charged in a reactor, and CDT and bromine are simultaneously dropped and reacted. However, the generated H
The problem that the heat resistance and melting point of BCD were low remained.

In the above reaction method, γ-H
Not only is the selectivity of BCD low, but side reactions such as bromination at the allylic position, dehydrobromination, bromination of the solvent, and the like are liable to occur in addition to the bromine addition reaction. However, there has been a problem that HBCD is mixed into the HBCD crystal. These impurities also corrode the molding machine,
It is known to cause coloring of the resin.

Therefore, there has been a demand for a highly selective production method of γ-HBCD having high thermal stability.

[0011]

Means for Solving the Problems In view of the above circumstances, the present inventors have conducted intensive studies on a highly selective method for producing γ-HBCD having high thermal stability. Bromine and CDT in an organic solvent containing
To produce HBCD, the hydrohalic acid is reacted with the alcohol in the reaction solvent in an amount of 3 to 30 w.
When the reaction is performed by adding t / vol%, the selectivity of γ-HBCD is remarkably improved, the side reaction with the reaction solvent can be suppressed, and the generation amount of impurities is significantly reduced as compared with the case where the reaction is not performed. And arrived at the present invention.

That is, according to the present invention, bromine is converted to CDT in an alcohol having 1 to 4 carbon atoms or an organic solvent containing the same.
Reacting with bromine to produce HBCD,
Before starting the reaction between CDT and bromine, hydrohalic acid is used as a reaction solvent in an amount of 3 to 30 wt / vol.
% Of HBCD.

Hereinafter, the present invention will be described in detail.

The solvent used in the method of the present invention is an alcohol having 1 to 4 carbon atoms or an organic solvent containing the same. As the alcohol having 1 to 4 carbon atoms, methanol,
Ethanol, n-propanol, isopropanol, n
-Butanol, sec-butanol, isobutanol,
tert-Butanol, ethylene glycol, diethylene glycol, propylene glycol and the like.
Among these alcohols, ethanol, n-propanol, tert-butanol and the like are particularly preferred. As the organic solvent to be mixed with the alcohol, ether solvents,
Examples thereof include halogen-based hydrocarbon solvents and ester-based solvents. The mixing ratio of each solvent to be mixed with the alcohol is not particularly limited. Specific examples of each solvent include:
Examples of ether solvents include dipropyl ether, diisopropyl ether, tetrahydrofuran (THF), dioxane, diethylene glycol dimethyl ether, and diethylene glycol diethyl ether, and examples of halogenated hydrocarbon solvents include carbon tetrachloride, chloroform, methylene chloride, and ethylene dichloride (EDC). ), Etc., and ethyl acetate, methyl acetate, 2-
Methoxyethyl acetate and the like can be mentioned. As a mixed solvent, ethanol-ethyl acetate, ethanol-THF,
Ethanol-dioxane, ethanol-EDC, ethanol-methylene chloride and the like are particularly preferable from the viewpoint of the reaction results.

The method for dissolving the hydrohalic acid in the reaction solvent is not particularly limited. For example, a method in which hydrohalic acid gas is directly blown into the reaction solvent, a method in which a reaction solvent containing hydrohalic acid is used, and a method in which hydrobromic acid is generated by reacting with bromine are reacted. There is a method of adding it in the system.

Regarding the timing of adding the hydrohalic acid,
In the case of reacting by dropping CDT while bromine is dissolved in the reaction solvent, the CDT must be added to the reaction solvent before dissolving the bromine in the reaction solvent in order to suppress the side reaction between the reaction solvent and bromine.
If bromine is dropped and reacted while bromine is dissolved, add hydrohalic acid before dropping bromine and CDT when reacting by dropping bromine and CDT simultaneously before starting the dropping of bromine. Just do it.

The amount of the hydrohalic acid to be added is 3 to 30 wt / vol% (hydrohalic acid / alcohol), preferably 5 to 20 wt / v with respect to the alcohol in the reaction solvent.
ol% is chosen. If the amount is less than 3 wt / vol%, the effect of adding the hydrohalic acid is small, and
/ Vol% or more does not further improve the effect,
It is not preferable from an economic viewpoint.

The type of hydrohalic acid used in the present reaction is hydrofluoric acid, hydrochloric acid, hydrogen bromide, hydroiodic acid or a mixture thereof, preferably hydrochloric acid and hydrobromic acid. is there.

The reaction method for carrying out the present invention includes a method in which bromine is dropped into CDT in a reaction solvent to cause a reaction, and a method in which CDT is dissolved in bromine in a reaction solvent.
And a method in which CDT and bromine are simultaneously dropped in the reaction solvent to cause a reaction. Any method may be used, but a method in which CDT and bromine are simultaneously dropped in the reaction solvent to cause a reaction. Has high heat resistance γ-HBC
This is preferable because the selectivity of D increases.

CD for practicing the method of the present invention
Substrate concentration of T (CDT / reaction solvent = wt / vol%)
Is disclosed in Japanese Patent Application No. 2-288453 in the case of reacting by dropping bromine while dissolving CDT in a solvent or the method of reacting by dropping CDT while dissolving bromine in a solvent. As described above, 0.1-20
wt / vol%, preferably 0.5 to 10 wt / vol
% Is chosen. Even when the reaction is performed at a concentration lower than 0.1%, the selectivity of γ-HBCD is not improved as expected as compared with the selectivity of γ-HBCD at 0.1 wt / vol%, and Not useful from an economic point of view. 20
If the reaction is performed in excess of wt / vol%, the selectivity of γ-HBCD is remarkably reduced, so that it is not selected. In the case of a method in which CDT and bromine are simultaneously dropped into the reaction solvent,
0.1 to 50 wt / vol%, preferably 0.5 to 40 wt / vol% is selected with respect to the organic solvent. 0.1%
Even if the reaction is carried out at a lower concentration, it is not useful from an economic point of view, and if it exceeds 40%, the slurry concentration becomes too high, which is not preferable.

The reaction temperature for carrying out the method of the present invention is not particularly limited, but when the reaction is carried out at a high temperature,
Substitution reactions other than the bromine addition reaction are likely to occur, so that impurities increase, and the reaction between the reaction solvent and bromine tends to occur. When the reaction is carried out at an extremely low temperature, the denaturation of the solvent is suppressed, but the reaction is not completed because the reaction rate is slow, and the reaction stops at a reaction intermediate, which is not preferable. The reaction temperature is usually about -20 ° C
It is in the range of about 50 ° C.

The reaction time for carrying out the present invention may vary depending on the reaction method, reaction temperature, charge amount, etc.
In the case of a method in which bromine is added dropwise to a reaction in which CDT is dissolved in a solvent and the reaction is performed, the addition time of bromine is usually about 10 minutes to 10 minutes.
Approximately 0 to 3 hours after the addition of CDT
It can be achieved by reacting for about an hour. In the case of a method of reacting by dropping CDT while bromine is dissolved in a solvent, the dropping time of CDT is usually about 10 minutes to 10 hours, and further, about 0 to 3 hours after the dropping of CDT is completed. Can be accomplished by doing CD in the reaction solvent
In the case of simultaneously dropping T and bromine, bromine and C
The time for dropping DT is usually about 10 minutes to 20 hours, and the reaction can be completed by reacting for about 0 to 3 hours after the completion of dropping of CDT.

The amount of bromine used for CDT is Br ₂ /
The CDT (molar ratio) is 3.0 or more, preferably 3.0 to 3.0.
5.0. If it is less than 3.0, the reaction is not completed because bromine is insufficient for CDT. If it exceeds 5.0, side reactions due to excess bromine are likely to occur, and this is not preferable from an economic viewpoint.

The HBCD produced after the completion of the reaction can be isolated as a powder by known means. For example, a method of filtering the precipitated crystals as they are, a method of taking the crystals by pouring the reaction solution at the end of the reaction into a poor solvent, and a method of pouring a poor solvent into the reaction solution at the end of the reaction can be considered. Further, the solvent recovered as a filtrate can be repeatedly used as a reaction solvent by replenishing a new solvent.

[0025]

By implementing the method of the present invention, H
It has become possible to produce a γ-isomer of BCD with high selectivity and high yield. Further, it has become possible to produce HBCD excellent in hue and thermal stability.

[0026]

EXAMPLES The present invention will be described in more detail with reference to the following Examples, but it should not be construed that the invention is limited thereto.

Examples 1 to 4 In a round bottom flask equipped with a reflux condenser and a stirring blade, Table 1 was prepared.
The reaction solvent and HBr were charged so as to obtain the composition shown in (1).
The reaction was carried out by dropping CDT and bromine in the amount shown in Table 1 at 15 ° C. over 2 hours. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, the reaction slurry is subjected to high performance liquid chromatography (column TSK gel-ODS8).
0TM, eluent acetonitrile / water = 80 / 20vo
1%, detector UV 215 nm) and the results are summarized in Table 1. Components that could not be identified were determined as unknown. DBCD (dibromocyclododecadien) and TBCD (tetrabromocyclododecene) in Table 1
Is a reaction intermediate of HBCD. Since TBCD has an isomer, OCD is determined by high performance liquid chromatography.
Analysis was performed using a DS reversed-phase column, and they were named α-TBCD and β-TBCD in the order of elution from the column.

The selectivity of γ-HBCD was represented by the value obtained by dividing the amount of γ-HBCD produced by the total amount of HBCD isomers [γ-HBCD / (α-TBCD + β-TBCD + γ-
HBCD)].

At the end of the reaction, the reaction solution was filtered, the obtained crystals were dried, and the melting points were measured. The results are shown in Table 1.

Examples 5 to 8 In a round-bottomed flask equipped with a reflux condenser and stirring blades, Table 1 was prepared.
The reaction solvent, HBr and bromine were charged so as to obtain the composition shown in (1). The amount of CDT shown in Table 1 was dropped therein at 15 ° C. over 2 hours to cause a reaction. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, post-treatment and analysis were carried out in the same manner as in the examples, and the results are summarized in Table 1.

Example 9 A round-bottomed flask equipped with a reflux condenser and stirring blades was prepared as shown in Table 1.
The reaction solvent, HBr and CDT were charged so as to obtain the composition shown in (1). The reaction was carried out by dropping bromine in the amount shown in Table 1 at 15 ° C. over 2 hours. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, post-treatment and analysis were carried out in the same manner as in the examples, and the results are summarized in Table 1.

[0032]

[Table 1] Comparative Example 1 Table 2 was placed in a round bottom flask equipped with a reflux condenser and stirring blades.
The reaction solvent having the composition shown in the following was charged. The reaction was carried out by dropping CDT and bromine in the amounts shown in Table 2 at 15 ° C. over 2 hours. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, post-treatment and analysis were carried out in the same manner as in the examples, and the results were summarized in Table 2.

Comparative Examples 2 and 3 Table 2 was placed in a round bottom flask equipped with a reflux condenser and stirring blades.
A reaction solvent having the composition shown in the following and bromine were charged. Table 2 in it
The reaction was carried out by adding dropwise the amount of CDT shown in (1) at 15 ° C. over 2 hours. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, post-treatment and analysis were carried out in the same manner as in the examples, and the results were summarized in Table 2.

Comparative Example 4 A round-bottomed flask equipped with a reflux condenser and stirring blades was prepared as shown in Table 2.
A reaction solvent having the composition shown in Table 1 and CDT were charged. The reaction was carried out by dropping bromine in the amount shown in Table 2 at 15 ° C. over 2 hours. After completion of the dropwise addition, the mixture was aged for 2 hours. After the completion of the reaction, post-treatment and analysis were carried out in the same manner as in the examples, and the results were summarized in Table 2.

[0035]

[Table 2]

Claims (1)

(57) [Claims] 1. A bromine is reacted with 1,5,9-cis, trans, trans-cyclododecatriene in an alcohol having 1 to 4 carbon atoms or an organic solvent containing the same to obtain 1,1
A method for producing 2,5,6,9,10-hexabromocyclododecane, wherein 3 to 30 wt / vol% of hydrohalic acid is added to alcohol in a reaction solvent. Of producing 5,5,6,9,10-hexabromocyclododecane.