JP4288715B2 - Method for producing tris (dibromopropyl) isocyanurate - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a method for producing tris (dibromopropyl) isocyanurate (hereinafter abbreviated as TAIC-6B) as a flame retardant for a synthetic resin.
[0002]
[Prior art]
Conventionally, as a method for producing TAIC-6B, triallyl isocyanurate (hereinafter abbreviated as TAIC) in a good solvent, a reaction solution obtained by reacting with bromine is added to a poor solvent for crystallization, A method for producing crystals by reacting TAIC with bromine in a mixed solvent of a good solvent and a poor solvent is known. For example, in Japanese Patent Application Laid-Open No. 56-53668, TAIC and bromine are reacted in an aliphatic halogenated hydrocarbon, and after completion of the dropwise addition of bromine, a saturated hydrocarbon having 5 or more carbon atoms is added to crystallize the reaction product. After filtration, the product is obtained. Further, the publication discloses a method of obtaining crystals by reacting TAIC and bromine in a mixed solvent of an aliphatic halogenated hydrocarbon and a saturated hydrocarbon having 5 or more carbon atoms, and filtering the obtained reaction solution. It is shown.
[0003]
[Problems to be solved by the invention]
However, the method described in JP-A-56-53668 is not satisfactory as an industrial production method. That is, when crystallization is performed by adding a saturated hydrocarbon having 5 or more carbon atoms to a reaction solution obtained by reacting TAIC and bromine in a good solvent, there is a problem that scaling or the like occurs at the initial stage of crystallization. It was. In the method of obtaining a crystal by reacting TAIC and bromine in a mixed solvent of an aliphatic halogenated hydrocarbon and a saturated hydrocarbon having 5 or more carbon atoms and filtering the resulting reaction solution, TAIC-6B There was a problem that the yield of was low, and it was not enough as an industrial manufacturing method.
[0004]
[Means for Solving the Problems]
As a result of intensive studies on the production method of TAIC-6B that can simplify the operability and have a good yield, the present inventors can perform the bromination of TAIC in a mixed solvent of a good solvent and a poor solvent. The reaction solution was heated by adding a poor solvent, and the good solvent was distilled off to crystallize the reaction product. As a result, it was found that TAIC-6B was obtained in a high yield, and the present invention was completed.
[0005]
That is, the present invention includes (1) adding a poor solvent to a reaction solution obtained by reacting TAIC and bromine in a mixed solvent of a good solvent and a poor solvent, and heating the reaction solution to distill off the good solvent. And the production method of TAIC-6B characterized by crystallizing the reaction product at a high recovery rate, and (2) reaction obtained by reacting TAIC and bromine in a mixed solvent of a good solvent and a poor solvent The liquid is heated while adding a poor solvent to the reaction liquid to distill off the good solvent, whereby the reaction product is crystallized at a high recovery rate.
[0006]
Hereinafter, the present invention will be described in detail.
[0007]
The good solvent used in the method of the present invention is not particularly limited as long as it can dissolve TAIC and is inert to bromine or has a very low reactivity, but in general, Halogenated hydrocarbon solvents are used. Specific examples include 1,1,1-trichloroethane, dichloromethane, chloroform, 1,1,2-trichloroethane, ethylene dichloride, methylene bromide, bromoform, and the like. The amount of the organic solvent used is not particularly limited, but it is desirable to use 2 to 50 times the weight ratio of TAIC provided for the reaction due to the viscosity of the reaction solution, economy and the like.
[0008]
In the method of the present invention, the poor solvent is not particularly limited as long as TAIC-6B does not dissolve and is inactive to bromine or has extremely low reactivity. What has the boiling point more than the boiling point of a solvent is preferable. Examples thereof include alcohols such as methanol, ethanol, n-propanol, and isopropanol, aliphatic hydrocarbons such as pentane, hexane, and cyclohexane, and water. These may be used alone or in combination. In the method of the present invention, water is not preferred as a poor solvent used in the reaction of TAIC and bromine.
[0009]
In the present invention, the combination of the good solvent and the poor solvent is preferably a poor solvent having a boiling point equal to or higher than the boiling point of the good solvent to be used. More preferably, it is 10 ° C. or higher. For example, methylene chloride (bp 39.8 ° C.)-Methanol (bp 64.5 ° C.), methylene chloride-isopropanol (bp 82.4 ° C.), methylene chloride-diisopropyl ether (b. 68.5 ° C), methylene chloride-heptane (bp 98.4 ° C), chloroform (bp 61.2 ° C) -heptane, methylene chloride-methanol-water, methylene chloride-isopropanol-water Suitable combinations include methylene chloride-diisopropyl ether-water, methylene chloride-heptane-water, chloroform-heptane-water, and the like. Of these, the combination of methylene chloride-heptane-water with good crystal dispersion is particularly preferred.
[0010]
In the bromination reaction step, it is important that the amount of the poor solvent used is such that the entire reaction product is not crystallized, and is usually 0.2 to 0.8 weight ratio with respect to the good solvent.
[0011]
After the bromination reaction is completed, the amount of the poor solvent to be added is one or two or more selected from the group consisting of alcohols and aliphatic hydrocarbons, and when water is used in combination with the above good solvent amount, respectively. Usually 0.2 to 0.8 weight ratio and 0.1 to 0.8 weight ratio. When only water is added, it is usually 0.5 to 1.5 weight ratio with respect to the previous good solvent.
[0012]
The amount of the poor solvent is not particularly limited, but an amount that is finally 2 to 10 times that of TAIC-6B is preferable.
[0013]
The amount of bromine used as the bromination reagent in the method of the present invention is usually 3 to 5 times the molar ratio with respect to TAIC included in the reaction, but preferably 3 to 3.5 times the molar ratio.
[0014]
The method of the present invention does not require a catalyst, but a catalyst may be used. The Lewis acid catalyst used is not particularly limited but is preferably soluble in an organic solvent. For example, antimony halides such as antimony trichloride, antimony pentachloride, and antimony tribromide, titanium halides such as titanium trichloride and titanium tetrachloride, and boron halides such as boron trichloride and boron tribromide. Alternatively, a boron halide complex such as boron trifluoride diethyl ether complex may be used. These may be used alone or in combination.
[0015]
The dropping temperature of bromine varies depending on the catalyst and the target bromination number, but is usually in the range of −30 to 50 ° C., preferably in the range of −5 to 40 ° C. Moreover, although the dripping time of bromine adjusts with the kind and addition amount of a catalyst, the density | concentration of TAIC, and the reaction temperature at the time of dripping, it is dripped normally about 1 to 12 hours. Immediately after the dropping, post-treatment may be performed, but aging may be performed at a predetermined temperature for 1 to 12 hours.
[0016]
After completion of the reaction, excess bromine may be transferred to the next step as it is, but may be reduced, for example, by adding a reducing agent such as hydrazine or sodium hydrogen sulfite.
[0017]
After completion of the reaction, after excess bromine is reduced or reduced, the poor solvent is added dropwise and then the good solvent is distilled off by heating, or the good solvent is distilled off while dropping the poor solvent. The dropping time of the poor solvent is usually no problem as long as it is 30 minutes or longer, and preferably in the range of about 1 to 3 hours in consideration of the dispersed state of the crystal.
[0018]
Although the good solvent is usually distilled under normal pressure, it can also be carried out under reduced pressure. A poor solvent may be added to adjust the slurry concentration during or after the good solvent is distilled off. After distillation of the good solvent, water may be further added to increase the amount of precipitated crystals. The amount of water at this time is not particularly limited, but is preferably 0.2 to 2 weight ratio with respect to the good solvent used in the reaction.
[0019]
TAIC-6B can be obtained as a product by filtering and drying the obtained slurry solution of TAIC-6B. The method for separation is not particularly limited, and examples thereof include centrifugation and suction filtration. Examples of the drying method include normal pressure drying, reduced pressure drying, and spray drying.
[0020]
【The invention's effect】
According to the present invention, high purity TAIC-6B can be obtained in high yield.
[0021]
【Example】
EXAMPLES Hereinafter, although an Example demonstrates this invention concretely, this invention is not limited only to these Examples.
[0022]
Example 1
A 1 L round bottom 4-neck round bottom flask equipped with a stirrer, a thermometer and a Dimroth condenser was charged with 60 g of TAIC, 394 g of dichloromethane and 202 g of heptane and brought to 30 ° C. on a water bath. The solution was added dropwise and further aged at the same temperature for 1 hour.
[0023]
After completion of the reaction, 60 g of water was added to the reaction solution, and then 5 g of 20% by weight hydrazine aqueous solution was added to reduce excess bromine.
[0024]
After reducing excess bromine, 202 g of heptane was charged into the dropping funnel and added dropwise at 30 ° C. over 1 hour.
[0025]
After dropping, the bath temperature was raised to 55 ° C. with stirring at normal pressure, and methylene chloride was distilled off.
[0026]
Distilling off was continued for about 30 minutes while heating the internal temperature to 70 ° C. After distilling off, the internal temperature was cooled to 30 ° C. TAIC-6B became white crystals and was uniformly dispersed in heptane / water.
[0027]
Thereafter, the TAIC-6B slurry solution was subjected to suction filtration, washed with water, and dried to obtain 163 g of the desired TAIC-6B white powder.
[0028]
Example 2
Using the same reactor as in Example 1, the same operation as in Example 1 was performed except that the poor solvent of the raw material was changed to isopropanol to obtain 162 g of TAIC-6B white powder.
[0029]
Example 3
Using the same reaction apparatus and raw materials as in Example 1, after distilling off methylene chloride, the internal temperature was cooled to 30 ° C., and the same operation as in Example 1 was carried out except that 200 g of water was added dropwise over 30 minutes. 168 g of 6B white powder was obtained.
[0030]
Example 4
Example 1 except that methylene chloride was distilled off while 202 g of heptane was added dropwise, the internal temperature was cooled to 30 ° C., and 200 g of water was added dropwise over 30 minutes, using the same reaction apparatus and raw materials as in Example 1. 168 g of TAIC-6B white powder was obtained.
[0031]
Comparative Example 1
Using the same reactor as in Example 1, the reactor was charged with 60 g of TAIC and 394 g of dichloromethane, adjusted to 30 ° C. on a water bath, 119 g of bromine was added dropwise over 4 hours, and further aged at the same temperature for 1 hour. It was.
[0032]
After completion of the reaction, 5 g of 20% by weight hydrazine aqueous solution was added, excess bromine was reduced, 202 g of heptane was charged into the dropping funnel, and dripping over 1 hour at a temperature of 30 ° C., scaling occurred. TAIC-6B I couldn't take it up.
[0033]
Comparative Example 2
Using the same reactor as in Example 1, the reactor was charged with 60 g of TAIC, 394 g of dichloromethane, and 202 g of heptane, adjusted to 30 ° C. on a water bath, and then dropped with 119 g of bromine over 4 hours, and further at the same temperature for 1 hour Aged.
[0034]
After completion of the reaction, 5 g of 20% by weight hydrazine aqueous solution was added to reduce excess bromine. Filtration was performed here to obtain 140 g of TAIC-6B white powder.

Claims (4)

A reaction product is obtained by adding a poor solvent to the reaction solution obtained by reacting triallyl isocyanurate and bromine in a mixed solvent of a good solvent and a poor solvent, and heating the reaction solution to distill off the good solvent. Is a method for producing tris (dibromopropyl) isocyanurate which crystallizes at a high recovery rate, and a combination of a good solvent and a poor solvent is methylene chloride-methanol, methylene chloride-isopropanol, methylene chloride-diisopropyl ether, methylene chloride -Selected from the group consisting of heptane, chloroform-heptane, methylene chloride-methanol-water, methylene chloride-isopropanol-water, methylene chloride-diisopropyl ether-water, methylene chloride-heptane-water, and chloroform-heptane-water. Made of featured tris (dibromopropyl) isocyanurate Method. The reaction solution obtained by reacting triallyl isocyanurate and bromine in a mixed solvent of a good solvent and a poor solvent is heated by adding the poor solvent to the reaction solution, and the good solvent is distilled off to react. A method for producing tris (dibromopropyl) isocyanurate in which a product is crystallized at a high recovery rate, wherein a combination of a good solvent and a poor solvent is methylene chloride-methanol, methylene chloride-isopropanol, methylene chloride-diisopropyl ether, Selected from the group consisting of methylene chloride-heptane, chloroform-heptane, methylene chloride-methanol-water, methylene chloride-isopropanol-water, methylene chloride-diisopropyl ether-water, methylene chloride-heptane-water, and chloroform-heptane-water. Tris (dibromopropyl) isocyanurate characterized by The method of production. The combination of the good solvent and the poor solvent is selected from the group consisting of methylene chloride-isopropanol, methylene chloride-heptane, methylene chloride-isopropanol-water, methylene chloride-heptane-water, and chloroform-heptane-water. A process for producing tris (dibromopropyl) isocyanurate according to claim 1 or 2 4. The production method according to claim 1, wherein the boiling point of the poor solvent is 10 ° C. or more higher than the boiling point of the good solvent used.