JPS6361944B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for producing tris(2,3-dibromopropyl)isocyanurate useful as a halogen flame retardant.

Tris (2,3-dibromopropyl) isocyanurate (hereinafter simply abbreviated as Br-TAIC) can be used in combination with other halogen-based compounds as well as compounds such as phosphorus compounds, antimony compounds, molybdenum compounds, and aluminum hydroxide. It is known as a compound that exhibits remarkable flame retardant effects on plastics and textile products.

Br-TAIC is a compound with a melting point of 105 to 120°C. Usually, triallyl isocyanurate (triallyl isocyanurate) is reacted with bromine using an aliphatic halogenated hydrocarbon as a reaction solvent, and after the reaction is completed, it is reacted with bromine such as methyl alcohol. A method has been adopted in which a lower aliphatic alcohol, which is a poor solvent for Br-TAIC, is added to the reaction system to precipitate and separate Br-TAIC from the reaction solution. The reason why the lower aliphatic alcohol is added after the reaction is completed is that the compound has a relatively high solubility in the aliphatic halogenated hydrocarbon that is the reaction solvent, and crystallization in the reaction solvent is very slow. This is used to forcibly promote this. According to this method, these solvents are recovered in a mixed state as a filtrate after separating the crystals. If this recovered mixed solvent is directly reused in the reaction, the reaction system will become non-uniform due to the influence of the poor solvent, and the viscous liquid will separate into layers before the reaction product crystallizes, causing damage to the reactor walls and the stirrer. etc., and these solidify over time, making the reaction and subsequent separation operations extremely difficult. Further, the presence of alcohol in the reaction system causes side reactions, resulting in impurities of unknown structure being mixed into the reaction product. In order to avoid such adverse effects, it is possible to separate the recovered mixed solvent by distillation and use it, but in this case, since the mixture of aliphatic halogenated hydrocarbon and aliphatic lower alcohol is azeotropic, It is impossible to separate by simple distillation. It is possible to avoid troubles in reaction and separation operations by distilling off alcohol, which is a poor solvent, as much as possible by azeotropic distillation and reusing the aliphatic halogenated hydrocarbon containing less alcohol in the reaction. The generation of impurities due to side reactions cannot be avoided and is undesirable in obtaining products of excellent quality.

The present inventor has improved the above drawbacks by adding a crystallization solvent that can be added to the reaction system to give Br-TAIC with good separation.
Preferably, the present invention was completed through research aimed at searching for a Br-TAIC crystallization solvent that would allow the reaction and crystallization solvent recovery mixed solvent to be reused as it is without purification and separation.

That is, the present invention provides tris(2, Tris(2,3-dibromopropyl)isocyanurate is precipitated and separated by adding a saturated hydrocarbon having 5 or more carbon atoms to a reaction mixture containing 3-dibromopropyl)isocyanurate, or aliphatic halogenated hydrocarbon and carbon Tris(2,3-dibromopropyl) characterized in that tris(2,3-dibromopropyl)isocyanurate is precipitated by reacting triallyl isocyanurate with bromine in the presence of a saturated hydrocarbon of number 5 or more. )
The gist of this paper is a method for producing isocyanurate.

In the present invention, Br-TAIC is a compound produced by the following reaction formula, and is produced by triallyl in the presence of an aliphatic halogenated hydrocarbon or an aliphatic halogenated hydrocarbon and a saturated hydrocarbon having 5 or more carbon atoms. Produced by the reaction of isocyanurate and bromine.

Examples of the aliphatic halogenated hydrocarbons used in the present invention include dichloromethane, chloroform, carbon tetrachloride, trichloroethane, tetrachloroethane, trichlorethylene, and tetrachlorethylene. Specific examples of aliphatic saturated hydrocarbons having 5 or more carbon atoms to be used as crystallization solvents include pentane, hexane, heptane, octane, nonane, and decane, which have straight chains or side chains. However, it is also possible to use a mixture of two or more types.
From an economic standpoint, aliphatic saturated hydrocarbons having 5 to 8 carbon atoms are preferred. Since none of the aliphatic saturated hydrocarbons having 5 or more carbon atoms listed here are azeotropic with aliphatic halogenated hydrocarbons, they can be separated by distillation and reused.

In the present invention, the aliphatic saturated hydrocarbon added as a crystallization solvent for the produced tris(2,3-dibromopropyl)isocyanurate can be added to the reaction solution after the completion of the reaction, as in the conventional method. Alternatively, by appropriately selecting a crystallization solvent, the recovered mixed solvent of the previously used reaction solvent and crystallization solvent can be used as a stress solvent without separation and purification. Accordingly, it is also possible to adopt a method in which the produced Br-TAIC is favorably crystallized during the reaction. Also, depending on the type and amount of crystallization solvent, it is possible to perform the reaction with a mixed solvent and then add a crystallization solvent after the reaction to obtain a good Br.
- A method of generating TAIC can also be adopted.

Since the crystallization solvent of the present invention does not form an azeotrope with the reaction solvent, in any of the above cases, the mixed solvent obtained after recovery can be recovered individually by distillation, if necessary. In particular, in a method in which aliphatic hydrocarbons are added to the reaction solvent in advance during the reaction, it is preferable to use a crystallization solvent in a range of types and amounts that can avoid difficulties in separation operations due to layer separation during the reaction, solidification of separated products, etc. However, the mixing amount varies depending on the type of reaction solvent and the amount used, and cannot be generalized. For example, when using dichloromethane as the aliphatic hydrocarbon and n-hexane as the crystallization solvent, the mixing ratio is n-hexane to 1 part by volume of dimechloromethane. The range is 0.9 to 1.3 parts by volume, and the amount used is triallyl isocyanurate 1
A range of 6 to 8 parts by volume of the mixed solvent can be mentioned based on parts by weight. In addition, when using tetrachlorethylene as the aliphatic hydrocarbon and n-pentane as the crystallization solvent, the mixing ratio is 0.2 to 0.5 n-pentane to 1 part by volume of tetrachlorethylene.
The amount used is 8 to 10 parts by volume of the mixed solvent per 1 part by weight of triallyl isocyanurate.

Example 1 30 g of triallylisocyanurate and 150 ml of carbon tetrachloride were added to a 500 ml reactor equipped with a thermometer, stirrer, and dropping funnel, and 57.8 g of bromine was added while cooling the reaction solution so that the temperature did not exceed 50°C. dripped. After bromine was added dropwise, continue stirring for 10 minutes, then add n-octane.
Gradually add 300ml dropwise to crystallize the reaction product, continue stirring for 60 minutes after adding n-octane, filter the crystals with suction through a glass filter, and wash the crystals three times with 50ml each of n-octane. After drying, 83 g of tris(2,3-dibromopropyl)isocyanurate were obtained.

Example 2 30 g of triallylisocyanurate and 100 ml of tetrachloroethylene were added to the same reactor as in Example 1, and 57.8 g of bromine was reacted in the same manner as in Example 1. Then, 300 ml of n-pentane was added to react the reaction product. After crystallization and filtration in the same manner as in Example 1, the crystals were washed three times with 50 ml of n-pentane and dried to obtain 84 g of tris(2,3-dibromopropyl) isocyanurate.

Example 3 Into the same reactor as in Example 1, 30 g of triallylisocyanurate and 30 ml of dichloromethane were added, and bromine was added.
After reacting 57.8g in the same way, add 150ml of n-hexane.
was added, crystallized and filtered in the same manner as in Example 1, and the crystals were washed three times with 50 ml of n-hexane and dried.
84 g of tris(2,3-dibromopropyl)isocyanurate were obtained.

Example 4 30 g of triallylisocyanurate, 100 ml of dichloromethane, and 100 ml of n-hexane were added to the same reactor as in Example 1, and 57.8 g of bromine was added dropwise while cooling the reaction solution so as not to exceed 50°C. After the dropwise addition of bromine, stirring was continued for 2 hours, and the resulting crystals were filtered to collect 145 ml of filtrate. Crystals in n-hexane
After washing three times with 50 ml each and drying, 68 g of tris(2,3-dibromopropyl) isocyanurate was obtained. The obtained tris(2,3-dibromopropyl)isocyanurate was analyzed by gas chromatography and was found to be a reaction intermediate, dis(2,3-dibromopropyl)isocyanurate.
3-dibromopropyl) isocyanurate 5.5
% and the purity was 94.5%.

The 145 ml of filtrate recovered from the first filtration was analyzed by gas chromatography.
Dis(2,3-dibromopropyl) isocyanurate 1.1g, tris(2,3-dibromopropyl)
18.5 g of isocyanurate was dissolved, along with 64.5 ml of dichloromethane and 67 ml of n-hexane. Add 35.5 ml of dichloromethane and n-
Add 33 ml of hexane, further add 30 g of triallylisocyanurate, and dropwise add 57.8 g of bromine while carrying out the reaction, filtration, washing, and drying in the same manner as in the first reaction to produce 87 g of tris (2,3-dibromopropyl).
Isocyanurate was obtained.

The resulting tris(2,3-dibromopropyl)
Isocyanurate was analyzed by gas chromatography and was found to be dis(2,3-dichloropropyl).
It contained 5.4% isocyanurate and had a purity of 94.6%.

For comparison, exactly the same reaction and operation was carried out using 100 ml of methanol instead of 100 ml of n-hexane in the first reaction to obtain 62 g of tris(2,3-dibromopropyl)isocyanurate. The obtained tris(2,3-dibromopropyl) isocyanurate was analyzed by gas chromatography and found to contain 5.6% of dis(2,3-dibromopropyl)isocyanurate and 3.8% of impurities of unknown structure, with a purity of 90.6%. It was hot.

Example 5 In a reactor similar to Example 1, 30 g of triallylisocyanurate, 100 ml of tetrachloroethane and n
- 30 ml of octane was added and 57.8 g of bromine was reacted in the same manner as in Example 1. After stirring for about 30 minutes after dropping bromine, 200 ml of n-octane was added to crystallize the reaction product. After passing in the same manner as in Example 1, the crystals were
It was washed three times with 50 ml of octane each time and dried. 84.5g
of tris(2,3-dibromopropyl)isocyanurate was obtained.

Claims (1)

[Claims] 1. Triallylisocyanurate and bromine are reacted in the presence of a solvent containing an aliphatic halogenated hydrocarbon, and a saturated hydrocarbon having 5 or more carbon atoms is added to the reaction mixture to form tris(2,3 A method for producing tris(2,3-dibromopropyl)isocyanurate, which comprises precipitating -dibromopropyl)isocyanurate. 2. The method for producing tris(2,3-dibromopropyl)isocyanurate according to claim 1, wherein the solvent containing an aliphatic halogenated hydrocarbon consists essentially of an aliphatic halogenated hydrocarbon. . 3. The tris(2,3- Method for producing dibromopropyl isocyanurate. 4 Precipitating tris(2,3-dibromopropyl)isocyanurate by reacting triallylisocyanurate and bromine in the presence of a solvent consisting of an aliphatic halogenated hydrocarbon and a saturated hydrocarbon having 5 or more carbon atoms. Tris (2,3-
Method for producing dibromopropyl isocyanurate.