JPH11217345A - Purification of bromine compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a purification method for obtaining a highly pure bromine compound excellent in thermal stability. SOLUTION: This purification method of a bromine compound by crystallizing the bromine compound from a crude solution containing the bromine compound of the formula [Ar<1> and Ar<2> are each mutually the same or different 6-10C aromatic hydrocarbon; Y is a 1-3C alkylene, a single bond, sulfone or ketone group; R<1> and R<2> are each mutually the same or different 2-5C hydrocarbon; (m) and (n) are each mutually the same or different integer of 1-4; (p) and (q) are each mutually the same or different integer of 2-4] is carried out (1) in the presence of a seed crystal, (2) by regulating the content of the crystal of the bromine compound so as to be 10-50 wt.% in the slurry comprising a good solvent, a poor solvent and the crystal of the bromine compound, and (3) by regulating the solubility of the bromine compound in the mixed solvent of the good solvent and the poor solvent so as to be 0.1-5 g/100 g-solvent in the slurry.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a method for purifying a specific bromine compound. More specifically, the present invention relates to a method for purifying a specific bromine compound capable of obtaining a bromine compound having high purity and excellent thermal stability.

[0002]

2. Description of the Related Art Generally, bromine compounds represented by ether derivatives of tetrabromobisphenol A exhibit excellent performance as flame retardants for polyolefin resins and styrene resins, and are widely used.

[0003] If such a bromine compound contains by-products produced during the production process, various types of these by-products adversely affect the thermal stability. Therefore, various purification means have been conventionally proposed.

For example, Japanese Patent Application Laid-Open No. Sho 49-125348 discloses that 2,2-bis [@ 3,5-dibromo-4-
Disclosed is a method of dissolving (2,3-dibromopropyloxy) {phenyl] propane (hereinafter sometimes abbreviated as TBA-BE) in a ketone-based solvent, cooling and precipitating.

[0005] Japanese Patent Application Laid-Open No. 55-111429 discloses a method of adding a halogenated aromatic hydrocarbon solution of TBA-BE to a mixture of methanol and a seed crystal.

In JP-A-4-234337, a poor solvent having a boiling point higher than that of a good solvent is dropped into a solution of TBA-BE dissolved in a good solvent. A method for recovering -BE as a fine powder is shown, and in JP-A-7-316087,
A TBA-BE solution dissolved in a good solvent is dropped into a heated poor solvent having a higher boiling point than the good solvent while stirring, and the TBA-BE crystals are dispersed and collected in the poor solvent while simultaneously distilling the good solvent. The method is described.

[0007] Japanese Patent Application Laid-Open No. Hei 8-113546 discloses TB
A-BE good solvent solution was added to heated methanol in the presence of seed crystals, and at the same time, the good solvent was distilled off and crystallized,
A method for recovering a solid having a large particle size is disclosed.

In Japanese Patent Application Laid-Open No. Hei 7-291883, water is added to an organic solvent solution of TBA-BE in the presence of a surfactant to form an emulsion, and then the organic solvent is removed to remove TBA-BE. A method for recovering powder is described.

Japanese Patent Application Laid-Open No. Hei 2-286645 discloses a method in which TBA-BE is kept in a molten state, and unpurified TBA-BE is added thereto.

Further, Japanese Patent Publication No. 57-289 discloses a method in which a non-solvent or a poor solvent is added to a good solvent solution of TBA-BE and stirring with shearing force is performed.

However, these methods require complicated operations and large-scale equipment, and the purity and thermal stability of the obtained solid are not always sufficient. Therefore, there is a demand for a purification method for obtaining a bromine compound having higher purity and excellent thermal stability with a simple apparatus.

[0012]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies for the purpose of providing a purification method for obtaining a bromine compound having improved purity and excellent thermal stability. In a method of purifying a bromine compound from, in the presence of seed crystals, a good solvent, a poor solvent and a crystal in a slurry composed of crystals of the bromine compound is a specific ratio,
By crystallizing the bromine compound while maintaining the condition that the solubility of the bromine compound in the mixed solvent in the slurry is within a certain range, it is possible to obtain a bromine compound having high purity and excellent heat stability. Heading, the present invention has been reached.

[0013]

According to the present invention, there is provided a method for crystallizing and purifying a bromine compound from a crude solution containing a bromine compound represented by the following general formula (1): Wherein (I) a seed crystal is present,
(II) The ratio of the bromine compound crystals in the slurry comprising the good solvent, the poor solvent, and the crystals of the bromine compound is 1
(III) a method for purifying a bromine compound, wherein the solubility of the bromine compound in a mixed solvent of a good solvent and a poor solvent in the slurry is 0.1 to 5 g / 100 g of a solvent. Is provided.

[0014]

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(Wherein, Ar ¹ and Ar ² are the same or different aromatic hydrocarbon groups having 6 to 10 carbon atoms; Y is an alkylene group having 1 to 3 carbon atoms, a single bond, a sulfone group or a ketone group; R ¹ and R ² are the same or different hydrocarbon groups having 2 to 5 carbon atoms; m and n are the same or different integers of 1 to 4; p and q are the same or different integers of 2 or 4)

According to the purification method of the present invention, when the obtained bromine compound is used as a flame retardant for a resin, a high-purity bromine compound which does not lower the thermal stability of the resin and does not cause coloring of the resin. Is obtained. In particular, according to the purification method of the present invention, when mixed with a resin, impurities having an undesirable effect are separated into a mixed solvent, and the desired bromine compound can be obtained as a high-purity solid in good yield. Become. Further, the purification method of the present invention is industrially excellent because continuous operation is easy and can be carried out with a simple apparatus and under mild conditions.

Hereinafter, the present invention will be described in more detail. In the present invention, the bromine compound to be purified is represented by the general formula (1). In the general formula (1), Ar ¹ and Ar ² are the same or different aromatic hydrocarbon groups having 6 to 10 carbon atoms, specifically, benzene, monomethyl-substituted benzene, dimethyl-substituted benzene or naphthalene, preferably Is benzene. Y
Is a bond or a group for bonding Ar ¹ and Ar ² , specifically, an alkylene group having 1 to 3 carbon atoms, a single bond, a sulfone group or a ketone group, preferably a methylene group or an isopropylidene group It is. R ¹ and R ² are the same or different and are a hydrocarbon group having 2 to 5 carbon atoms, specifically, an ethyl group, a propyl group, an isopropyl group, a butyl group or an isobutyl group, and preferably have 2 or 3 carbon atoms. It is an ethyl group or a propyl group. m
And n represent the same or different integers of 1 to 4, preferably 1 or 2. p and q represent the same or different integers of 2 or 4, preferably 2.

As the bromine compound represented by the general formula (1), specifically, 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] Propane, 2,2-bis [{3,5-dibromo-4- (2,3-dibromo-2-methylpropyloxy)} phenyl] propane, bis [{3,5-dibromo-4- (2,3 -Dibromopropyloxy) @phenyl] methane, bis [@ 3,5-dibromo-4- (2,3
-Dibromo-2-methylpropyloxy) @phenyl]
Methane, bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] sulfone, bis [{3,5-dibromo-4- (2,3-dibromo-2-)
Methylpropyloxy) {phenyl] sulfone, {3
3 ', 5,5'-tetrabromo-4,4'-(2,3-
Dibromopropyloxy) biphenyl, 3,3 ',
5,5'-Tetrabromo-4,4 '-(2,3-dibromo-2-methylpropyloxy)} biphenyl and {3,3', 5,5'-tetrabromo-4,4'-
(1,2-dibromoethyloxy)} biphenyl and the like, and among them, 2,2-bis [{3,5-dibromo-
4- (2,3-dibromopropyloxy) @phenyl]
Propane is preferably used.

The purification method of the present invention is carried out by precipitating a high-purity solid bromine compound from a crude solution containing the bromine compound represented by the general formula (1).
The crude solution is, specifically, a solution containing a bromine compound produced by an addition reaction of bromine (Br ₂ ).
This addition reaction is a reaction for brominating an unsaturated bromine compound represented by the following general formula (2), and the purification method of the present invention is advantageously applied to a solution obtained by this reaction.

[0020]

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(Wherein, the definitions of Ar ¹ , Ar ² , Y, m and n mean the same as in the general formula (1).
Q ¹ and Q ² are the same or different and represent a C 2-5 hydrocarbon group having one or two unsaturated groups. )

In the general formula (2), Ar ¹ , A
The definitions of r ² , Y, m and n have the same meanings as in the general formula (1), and the preferred definitions also have the same meanings. Specific examples of the hydrocarbon group for Q ¹ and Q ² include a vinyl group, an allyl group and an isobutenyl group, and preferably an allyl group.

As the unsaturated bromine compound represented by the general formula (2), specifically, 2,2-bis {(3,5-dibromo-4-allyloxy) phenyl} propane, 2,2
2-bis {(3,5-dibromo-4-isobutenyloxy) phenyl} propane, bis {(3,5-dibromo-
4-allyloxy) phenyl {methane, bis} (3,5
-Dibromo-4-isobutenyloxy) phenyl} methane, (3,3 ', 5,5'-tetrabromo-4,4'-
Diallyloxy) biphenyl, (3,3 ', 5,5'-
Tetrabromo-4,4'-divinyloxy) biphenyl, bis {(3,5-dibromo-4-allyloxy) phenyl} sulfone and bis {(3,5-dibromo-
4-isobutenyloxy) phenyl} sulfone, among which 2,2-bis {(3,5-dibromo-4-allyloxy) phenyl} propane and 2,2-bis} (3,5- Dibromo-4-isobutenyloxy) phenyl {propane, bis {(3,5-dibromo-4-allyloxy) phenyl} methane, bis {(3,5-dibromo-4-isobutenyloxy) phenyl} methane,
(3,3 ', 5,5'-Tetrabromo-4,4'-diallyloxy) biphenyl and (3,3', 5,5'-
Tetrabromo-4,4'-divinyloxy) biphenyl is preferred, and 2,2-bis {(3,5-dibromo-4-allyloxy) phenyl} propane, 2,2-
Bis (3,5-dibromo-4-isobutenyloxy)
Phenyl {propane, bis} (3,5-dibromo-4-
Allyloxy) phenyl {methane and bis} (3,5
-Dibromo-4-isobutenyloxy) phenyl {methane is more preferred, and 2,2-bis {(3,5-dibromo-4-allyloxy) phenyl} propane is particularly preferred.

The reaction between the unsaturated bromine compound and bromine is as follows:
The reaction is carried out in the presence of a solvent, which is inert without adversely affecting the reaction. The higher the solubility of the solvent for the unsaturated bromine compound is, the more preferable it is, but the solvent may be partially soluble. Further, it is preferable that the bromine compound generated by the bromination reaction of the unsaturated bromine compound is substantially dissolved in the solvent.

The solvent in the bromination reaction is not only used as a mere solvent for performing the reaction uniformly, but also preferably functions as a solvent for effectively removing the heat of reaction out of the reaction system. have. Therefore, the solvent has a normal pressure boiling point of 0 to 100 ° C, preferably 20 to 90 ° C.
In particular, when the heat of reaction is substantially removed by the heat of vaporization of the solvent, those having a normal pressure boiling point of 20 to 80 ° C, particularly 20 to 60 ° C, are desirable.

Examples of the solvent include halogenated hydrocarbons such as methylene chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane, bromoethane, butyl chloride and chloropropane; diethyl ether, ethyl isopropyl ether, tetrahydrofuran, dioxane and the like. Ether hydrocarbon compounds, aromatic hydrocarbon compounds such as toluene, cyclohexanone, ethyl acetate and the like. Also, bromine can be used as a solvent.

Of these solvents, halogenated hydrocarbons are preferred, and methylene chloride and chloroform are particularly preferred as solvents. These solvents are used alone or in combination of two or more. These halogenated hydrocarbons can also be used as a mixed solvent with dioxane.

The amount of bromine used in the above bromination reaction may be a sufficient molar ratio to the unsaturated bromine compound in order to obtain a desired bromine compound. The bromine is preferably used in an amount corresponding to the number of 1 to 5 bromine molecules, more preferably in an amount corresponding to the number of 1.1 to 3 bromine molecules.

In the bromination reaction, bromine is used by itself or as a bromine solution. As the solvent used in the bromine solution, the same solvent as described above is used, and in this case, the concentration of bromine is preferably in the range of 10 to 90% by weight.

In the above bromination reaction, as specific means,
By mixing a solution of an unsaturated bromine compound in a solvent inert to the reaction with bromine or a bromine solution, the unsaturated bromine compound is reacted with bromine. At the time of this bromination reaction, it is preferable to remove a substantial amount of the heat of the bromination reaction by a solvent or the heat of vaporization of bromine. The substantial amount of the heat of reaction refers to the theoretical calorific value generated by the desired bromination reaction of 8
0% or more, preferably 85% or more.

As described above, the reaction temperature in the bromination reaction is preferably a temperature at which a substantial amount of the heat of the bromination reaction is removed by the heat of vaporization of bromine or the solvent, and the bromination reaction is limited to normal pressure. Instead, it can be performed under pressure or under reduced pressure. The reaction temperature can be controlled by operating pressure, depending on the type of solvent used (boiling point) and the amount of bromine. Usually, the reaction temperature is in the range from 0 to 60 ° C, preferably in the range from 5 to 55 ° C, particularly preferably 10 to 55 ° C.
A range of ５０50 ° C. is advantageous.

The purification method of the present invention is advantageously applied to the separation of a purified bromine compound from a reaction mixture obtained by the above-mentioned bromination reaction. Since the reaction mixture is obtained as a crude solution containing a bromine compound, the solution can be directly subjected to the purification treatment of the present invention. However, unreacted bromine remains in the above reaction mixture, and the residual bromine adversely affects the purification step and the recovery step, so that it can be converted to another compound by performing a chemical treatment. desirable.

This chemical treatment employs a method in which residual bromine in the reaction mixture is treated with a reducing agent, bromine is once converted into hydrobromic acid, and then hydrobromic acid is neutralized with an alkaline neutralizing agent. Is done. The method is carried out by adding a reducing agent and a neutralizing agent to the reaction mixture.

The reducing agent used in this treatment method is a reducing agent used in a usual reduction reaction, and specifically, sodium hydrogen sulfite, sodium dithionite, sodium sulfite, oxalic acid, hydrogen sulfide , Sodium nitrite, potassium nitrite, hydroxylamine sulfate,
Examples include tin, stannous oxide, and hydrazine. Of these, sodium bisulfite, sodium dithionite, sodium sulfite, oxalic acid, and sodium nitrite are preferably used. These reducing agents can also be used as an aqueous solution. These reducing agents are used alone or in combination of two or more.

Examples of the alkaline neutralizer include alkali metal hydroxides, alkali metal carbonates, alkaline earth metal hydroxides and alkaline earth metal carbonates. Sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, calcium hydroxide, calcium carbonate, and the like are preferable, and sodium hydroxide is particularly preferably used. These alkaline neutralizing agents are preferably used as an aqueous solution. Also,
These alkaline neutralizing agents are used alone or in combination of two or more.

In the above treatment method, 2 mol or more, preferably 2 to 3 mol, per 1 mol of residual bromine in the reaction mixture.
0 mol, more preferably 2.2 to 15 mol, even more preferably 2.5 to 10 mol of reducing agent are added to the reaction mixture. When the amount of the reducing agent to be added is within such a range, bromine does not remain in the mixture and a bromine compound of high purity and without discoloration is obtained, which is preferable. Further, 2 mol or more, preferably 2 to 2 mol, per 1 mol of the residual bromine in the reaction mixture.
50 mol, more preferably 2.2 to 30 mol, even more preferably 2.5 to 20 mol of alkaline neutralizing agent are added to the reaction mixture. When the addition amount of the neutralizing agent is within the above range, hydrogen bromide does not remain in the aqueous solution, and this aqueous solution can be discarded as it is, and there is no corrosion of metal, which is preferable in working environment.

The reducing agent and the alkaline neutralizing agent are as follows:
The bromine compound and the bromine-containing reaction mixture are added simultaneously or separately. Such a reducing agent and a neutralizing agent may be added separately or in advance, but it is preferable to add them separately since there is no possibility that the reducing agent may cause a side reaction due to alkali. As the addition method, a method in which a reducing agent is added followed by a neutralizing agent is preferably adopted. In the treatment method, the reaction mixture to which the reducing agent and the alkaline neutralizing agent have been added is reduced,
The components are mixed so that the neutralization reaction proceeds smoothly.

The weight ratio of the reaction mixture to the aqueous phase at the time of performing the reduction and neutralization reactions is from 20:80 to 80:
20 is preferable, 30:70 to 70:30 is more preferable, and 40:60 to 60:40 is particularly preferable. Within this range, the reduction and neutralization reactions proceed efficiently, and bromine is removed in a short time. Therefore, when performing reduction and neutralization reactions,
It is preferable to add water or a solvent to the reaction mixture so as to fall within the above range.

The time required for the reduction and neutralization of bromine in the reaction mixture is preferably 2 minutes or more, more preferably 2 to 90 minutes, still more preferably 5 to 60 minutes, and more preferably 10 to 45 minutes.
Minutes are particularly preferred.

After the above-mentioned reduction treatment and neutralization treatment, the reaction mixture (organic phase) is separated from the aqueous phase, and this organic phase can be used as a crude solution in the purification method of the present invention.

The crude solution to which the purification method of the present invention is applied is prepared by adding the bromine compound represented by the above general formula (1) to 10-8.
It is desirably contained at a concentration of 0% by weight, preferably 20 to 65% by weight, particularly preferably 25 to 55% by weight.

The solvent forming the crude solution of the bromine compound is
It is a good solvent for bromine compounds. Such a good solvent preferably has a bromine compound solubility of 1 g / 100 g or more, preferably 2 g / 100 g or more at 25 ° C. Examples of good solvents include methylene chloride, chloroform, 1,
Those selected from 2-dichloroethane, 1,1-dichloroethane, cyclohexanone, ethyl acetate and toluene are preferable, and these may be one kind or a mixture of two or more kinds. Of these, more preferred are halogenated hydrocarbons such as methylene chloride and chloroform, with methylene chloride being most preferred.

As mentioned above, the crude solution of the bromine compound can be the reaction mixture produced by the bromination reaction or a solution derived from the mixture, in which case it was used in the bromination reaction. It is a solution of the reaction solvent as it is or a solution subjected to additional chemical treatment.

In the purification method of the present invention, the crude solution containing the bromine compound represented by the general formula (1) as described above is supplied into a slurry satisfying the following conditions (a) and (b). Therefore, it is important to precipitate the bromine compound in the crude solution in the presence of the seed crystal. In this case, the solvent in the slurry is a mixed solvent of a good solvent and a poor solvent for the bromine compound as shown in (b) below.

(A) the ratio of the bromine compound crystals in the slurry comprising the good solvent, the poor solvent and the bromine compound crystals is 10 to 50% by weight, preferably 15 to 40% by weight; b) The solubility of the bromine compound in a mixed solvent of a good solvent and a poor solvent in the slurry is 0.1%.
1-5 g / 100 g of solvent, preferably 0.5-4 g / 100 g of solvent.

The purification method of the present invention is carried out by supplying a crude solution containing a bromine compound into a deposition vessel while maintaining the conditions (a) and (b). Some of the bromine compound crystals forming the slurry act as seed crystals of the bromine compound precipitated from the solution, while the composition of the mixed solvent promotes the bromine compound precipitation and suppresses the precipitation of impurities. In addition, it is considered that it has an effect of maintaining its dissolution.

The seed crystal used in the present invention preferably has a purity of 90% or more. Such seed crystals include:
The same bromine compound as the bromine compound in the crude solution of the bromine compound to be used is preferably used. By using a seed crystal, a high-purity bromine compound with less impurities is obtained in order to smoothly precipitate the bromine compound crystal from the crude solution of the bromine compound, and to prevent the generation of microcrystals. The crystals of the obtained bromine compound have a uniform particle size.

In the purification method of the present invention, crystallization of the bromine compound proceeds in the slurry. The slurry in the present invention is composed of crystals of a good solvent, a poor solvent, and a bromine compound. More specifically, a slurry in which a solvent and a non-crystallized bromine compound are dissolved in a solvent of a good solvent and a poor solvent has a slight impurity. And the crystal part of the bromine compound contained.

The crystals of the bromine compound in the slurry include both the seed crystals and the crystals of the bromine compound precipitated from the solution of the bromine compound.

Thus, in carrying out the method of the present invention, in addition to supplying the crude solution to the precipitation vessel, the vessel is further provided with the above conditions so that the above conditions (a) and (b) are maintained. A poor solvent, a seed crystal or a mixture thereof can be supplied. At this time, if necessary, a good solvent or a mixed solvent of a good solvent and a poor solvent can be supplied.

In the purification method of the present invention, when the value of the volume ratio between the good solvent and the poor solvent in the slurry (good solvent / poor solvent) is a, the volume of the good solvent and the poor solvent in the added component is The ratio (good solvent / poor solvent) value is in the range of 0.5a to 2.0a,
The bromine compound is preferably in the range of 0.7a to 1.5a, more preferably in the range of 0.8a to 1.2a, and particularly preferably in the same volume ratio as that of the good solvent and the poor solvent in the slurry. It is desirable to feed a crude solution containing the and a poor solvent into the slurry. This method is preferably adopted because the fluctuation in the volume ratio between the good solvent and the poor solvent in the slurry is small, the effect of removing impurities is high, and the production efficiency of the bromine compound is good.

As a poor solvent for the bromine compound, the solubility of the bromine compound is 0.08 g / 100 g or less of the solvent, preferably 0.05 g / 100 g or less of the solvent, particularly preferably 0.0 g / 100 g or less of the solvent.
Advantages are 1 g / 100 g solvent or less. Here, the solubility is a value measured at a temperature of 25 ° C. The solubility of the good solvent and the mixed solvent also means a value measured at 25 ° C.

Specific examples of the poor solvent include, for example,
Water, methanol, ethanol, saturated monohydric alcohol having 1 to 5 carbon atoms such as i-propanol, ethylene glycol, glycerin, diethyl ether, dipropyl ether, diisopropyl ether and n-pentane;
Examples thereof include saturated hydrocarbons having 5 to 10 carbon atoms such as hexane and n-octane, and water, methanol, ethanol, i-
Propanol and diisopropyl ether are preferred, water, methanol, ethanol and i-propanol are more preferred, and methanol is particularly preferred.
These poor solvents are used alone or in combination of two or more.

In a preferred embodiment of the present invention, the bromine compound is 2,2-bis [@ 3,5-dibromo-4-.
(2,3-dibromopropyloxy) @phenyl] propane, the good solvent in the slurry is methylene chloride, and the poor solvent is methanol, the weight ratio of methylene chloride to methanol in the slurry is And 30:70
７０70: 30, preferably 40: 60-6.
The ratio is more preferably 0:40.

The operation of precipitating the bromine compound in the purification method of the present invention does not particularly require cooling or heating.
It is advantageous to work at a temperature in the range of 50 ° C, preferably in the range of 10 to 45 ° C. When performed within such a temperature range, a good solvent is present in the slurry, and crystallization proceeds gradually, so that a high-purity bromine compound is easily obtained, and the crystal form (particle size) There is an advantage that control becomes easy. Furthermore, by setting the crystallization temperature higher, a bromine compound with a reduced residual solvent can be easily obtained, and a high purity bromine compound can be obtained because the solubility of the impurities in the mixed solvent in the slurry increases. It is preferably adopted because it becomes easy.

The bromine compound crystal particles in the slurry preferably have an average particle diameter of 0.1 to 0.8 mm, preferably 0.2 to 0.7 mm.

The purification method of the present invention can be carried out by either a batch method or a continuous method. However, since the method of the present invention is a method suitable for a continuous method, the continuous method is industrially advantageous.

Next, specific embodiments of the batch method and the continuous method will be described. In order to simplify this description, the following terms have the following meanings, respectively. Crude solution; crude solution containing bromine compound Good solvent; good solvent for bromine compound poor solvent; poor solvent for bromine compound Mixed solvent; mixed solvent of good solvent and poor solvent Container; stirrer for precipitating bromine compound Container with

First, the mode of the purification operation by the batch method will be described. The batch method can be classified into the following (1) to (4). (1) A method in which a crude solution and a poor solvent are supplied into a container previously filled with a solid-liquid mixture composed of a seed crystal and a mixed solvent. (2) A method in which three liquid flows of (A) a crude solution, (B) a poor solvent, and (C) a solid-liquid mixture composed of a seed crystal and a mixed solvent are supplied into a container. (3) A method in which two liquid streams of (A) a crude solution and (C) a solid-liquid mixture composed of a seed crystal and a mixed solvent are supplied into a container. (4) A method in which three liquid streams of (A) a crude solution, (B) a poor solvent, and (D) a solid-liquid mixture composed of a seed crystal and a poor solvent are supplied into a container.

The methods (1) to (4) are for explanation of the batch method, and slight modification or addition may be made at all. For example, in the method (1), a good solvent may be further supplied into the container, or a solid-liquid mixture composed of the seed crystal and the mixed solvent may be supplied into the container. Also,
In the methods (1) to (4), the composition and the supply speed of each liquid stream need not be constant and may be changed. Further, in the batch method, a method in which part of the slurry in the container is taken out and circulated and supplied again into the container may be adopted.

The solid-liquid mixture used in the above methods (1) to (4) is a mixture before mixing with other components, and is a mixture of (C) a seed crystal and a mixed solvent or (D) A mixture comprising a seed crystal and a poor solvent. In the present invention, a mixture obtained by mixing a solid-liquid mixture with other components is referred to as a slurry.

In the above methods (1) to (4), it is desirable to mix the slurry in the container well by means of stirring or the like in order to enhance the precipitation effect and obtain a high-purity bromine compound. is there.

In the above methods (1) to (4), the methods (1) to (3) are particularly preferable in that the solid-liquid mixture comprising the seed crystal (C) and the mixed solvent is used to obtain the slurry. The bromine compound crystal is preferably employed because it is likely to have a somewhat swollen state and the impurities are easily removed. Furthermore, the methods (1) and (2) are more preferably employed because the ratio between the good solvent and the poor solvent is easily controlled, and the crystal form (particle size) of the obtained bromine compound is easily controlled. .

Next, an embodiment of the continuous method will be described. The continuous method is basically a method in which a bromine compound is precipitated in a container while a crude solution is continuously supplied into the container, and a slurry is continuously or intermittently taken out from the container.

According to the present invention, the following method is proposed as a preferred embodiment for continuously carrying out the method of the present invention. That is, according to the present invention, there is provided a method of crystallizing and continuously purifying a bromine compound from a crude solution containing a bromine compound represented by the general formula (1), wherein (I) the crude solution Is continuously supplied to a container containing a slurry containing the bromine compound crystals together with a poor solvent to precipitate the bromine compound in the slurry with stirring. (II) At this time, the good solvent in the container is , The ratio of the bromine compound crystals in the slurry comprising the poor solvent and the bromine compound crystals is 10
(III) At this time, the solubility of the bromine compound in the mixed solvent of the good solvent and the poor solvent in the slurry in the container is 0.1 to 5 g / solvent 10
0 g, and (IV) a method for continuously purifying a bromine compound, comprising continuously taking out the slurry from the vessel and separating crystal particles of the bromine compound from the slurry.

The above-described continuous method may be further modified or added as described below in a concrete implementation. (A) A good solvent can be additionally supplied into the container. (B) A part of the slurry taken out of the container can be circulated again into the container. (C) The slurry taken out of the container may be separated into a wet cake of bromine compound and mother liquor by solid-liquid separation, and a part of the mother liquor may be supplied into the container. This circulating supply of the mother liquor is a preferred embodiment because it serves to improve the recovery of the target bromine compound.

The above-described embodiments (a) to (c) may be carried out independently, or may be carried out in any combination.

The slurry containing bromine compound crystals obtained by the above batch method and continuous method is separated into a wet cake and a mother liquor by centrifugation or filtration, and the wet cake is dried and optionally ground. By
Crystals of the desired high-purity bromine compound can be obtained.

The bromine compound obtained in the present invention has an average particle diameter on a weight basis of preferably from 0.1 to 0.9 mm, more preferably from 0.1 to 0.8 mm, and preferably from 0.2 to 0.8 mm.
A range of .about.0.7 mm is preferred. A bromine compound having an average particle size in such a range has good handleability, does not cause scattering of dust, and has good dispersibility when the bromine compound is blended into a resin as a flame retardant, and thus is preferable.

According to the purification method of the present invention, a high-purity bromine compound can be industrially advantageously obtained and is useful as a flame retardant for resins, and particularly for ABS resins, polystyrene resins and polyolefin resins. It is an excellent high-quality flame retardant.

[0071]

The present invention will be described below in detail with reference to examples. The following methods were used to measure the purity, the average particle size, the solubility, the proportion of crystals in the slurry, and the specific gravity.

(1) Analysis of Purity The purity of the bromine compound was measured by high-performance liquid chromatography (SCL-6B manufactured by Shimadzu Corporation) for 280.
The measurement was performed by a method of detecting the absorption in nm. The sum of the peak areas of the components obtained from the chromatography was defined as 100, and the ratio of the peak area of the bromine compound to the sum was determined.

(2) Average Particle Size Samples were prepared for 200, 100, 60, 20, 16, 10,
After sieving using a 5,3.5 mesh sieve, a cumulative particle size distribution graph based on weight was created to determine the average particle size.

(3) Solubility At a predetermined temperature, an excess of the sample powder is dissolved in a predetermined solvent, and after the solution is completely saturated at that temperature, a certain amount of this solution is accurately measured, and then the solvent is removed from the solution. After complete removal,
The remaining weight was measured to calculate the solubility of the sample in the solvent.

(4) Proportion of Crystals in Slurry A certain amount of the slurry was filtered to take out crystals,
After drying at 5 mmHg at 3 ° C. for 3 hours, the weight of the crystal was measured, and the weight ratio of the crystal to the slurry was calculated.

(5) Specific gravity The specific gravity was measured at 20 ° C. using a glass specific gravity bottle.

Reference Example A 2,93% pure 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane was recrystallized using ethyl acetate. Was. As a result, 2,2-bis [@ 3,5-dibromo-4-] having a purity of 94% and an average particle diameter of 0.2 mm was obtained.
Crystals of (2,3-dibromopropyloxy) {phenyl] propane were obtained (hereinafter, abbreviated as seed crystal A).
Furthermore, recrystallization was performed in the same manner twice, and 2,2-bis [｛3,5-dibromo- having a purity of 99% and an average particle diameter of 0.2 mm was used.
4- (2,3-dibromopropyloxy) @phenyl]
Propane crystals were obtained (hereinafter, abbreviated as seed crystals B).

Reference Example B 100 g (0.160 mol) of commercially available TBA-AE (manufactured by Teijin Chemicals Ltd., FG-3200) and 150 g of methylene chloride were placed in a flask equipped with a thermometer, a stirrer, and a reflux condenser. And dissolved at 20 ° C. To this solution was added 54 g (0.338 mol) of bromine in 1
It was added dropwise over time, and stirring was continued at the same temperature for 1 hour.
The bromine addition reaction was completed.

Next, excess bromine in this solution was reduced with 30 ml of a 25% by weight aqueous solution of sodium hydrogen sulfite, and the produced hydrogen bromide was neutralized with 11 ml of a 24% by weight aqueous solution of sodium hydroxide. After washing with water, a 50% by weight solution of TBA-BE in methylene chloride was obtained. Also, add a methylene chloride solution to this solution,
A 33% strength by weight methylene chloride solution was prepared. A part of this solution was taken out and concentrated. The purity of the solid was 90%.
Met.

Reference Example C 1000 g (1.60 mol) of 2,2-bis {(3,5-dibromo-4-allyloxy) phenyl} propane (raw compound (1)) was added to 1703 g (20.0 mol) of methylene chloride. Dissolved. This solution had a specific gravity of 1.46 and contained 160 ppm of water as measured by the Karl Fischer method.

This solution was placed in a glass reaction vessel equipped with a stirring blade, a condenser and a thermometer through the inlet.
At a rate of 3 × 10 ⁻³ L / min, 0.58
It was continuously added at a rate of × 10 ⁻³ L / min (the number of bromine molecules / the number of unsaturated groups in the starting compound (1) was 1.23). The solution mixed in the reaction vessel generates heat due to the heat of bromination reaction,
The vaporized vapor was refluxed to the reaction vessel by a well-cooled condenser. About 20 minutes after the start of the addition of the solution of the raw material compound (1) and the bromine, the reaction mixture began to be drawn out from the outlet, and was continuously drawn out thereafter (residence time: 20.4 minutes). In addition, a reaction vessel (120 m
As for the reaction mixture in l), a part of the reaction mixture was circulated into the reaction vessel at a rate of 0.03 L / min using a pump from the time when the reaction mixture began to be discharged.

In the reaction mixture discharged from the reaction vessel, excess bromine was reduced with an aqueous sodium hydrogen sulfite solution (about 15% by weight), and the generated hydrogen bromide was neutralized with an aqueous sodium hydroxide solution. Thereafter, 1000 g of ion-exchanged water was added to this solution, and the mixture was stirred. The methylene chloride layer was separated, and solid 2,2-bis {3,5-dibromo-4- (2,3- The purity of dibromopropyloxy) phenyl-propane was 94.2%. The concentration of the bromine compound in the methylene chloride layer was 50.2%.

Example 1 In a flask shown in FIG. 1, 2.5 kg of methylene chloride, 2.5 kg of methanol and 2.5 kg of seed crystal B obtained in Reference Example A were mixed and mixed (this solid-liquid mixture). Has a specific gravity of 1.15 and a capacity of 6.
5L. ).

While stirring the inside of the flask, at a temperature of 25 ° C., the 90% pure 2,2-bis [５−3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) [Phenyl] propane in 50% strength by weight methylene chloride solution, methanol and the weight ratio of methylene chloride to methanol was 50:50, and the ratio of seed crystal B obtained in Reference Example A was 33% by weight. A certain solid-liquid mixture was dispensed by a metering pump at 0.05 L / min.
It was added continuously at a rate of 05 L / min and 0.03 L / min for 8 hours. Ten minutes after the start of the addition, the slurry was withdrawn from the outlet 8 at a rate of 0.13 L / min while the slurry in the flask was circulated at a rate of 3.5 L / min by the pump 6 (residence time was 60 minutes). The slurry withdrawn between 7 and 8 hours after the start of the addition is filtered,
By drying under reduced pressure at 5 mmHg at 80 ° C. for 3 hours, 2,2-bis [｛3,5-dibromo-4- (2,3
[Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals had a purity of 96%, an average particle diameter of 0.4 mm, and a recovery of 96%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 and 2,2-bis [｛3,5-dibromo-4- (2,3-dibromopropyloxy) at 25 ° C. [Phenyl] propane (hereinafter, referred to as "
TBA-BE) is 0.7
g / 100 g of solvent and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 2 In a flask shown in FIG. 1, 2.5 kg of methylene chloride, 2.5 kg of methanol and 2.5 kg of a seed crystal B obtained in Reference Example A were mixed and mixed (this solid-liquid mixture). Has a specific gravity of 1.15 and a capacity of 6.
5L. ).

While stirring the inside of the flask, at a temperature of 25 ° C., the 90% pure 2,2-bis [−3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) A solution of methylene chloride at a concentration of 50% by weight of [phenyl] propane and methanol were metered at a rate of 0.05 L / min and 0.05 L / min by a metering pump, respectively.
Added continuously over time. 10 minutes after starting the addition,
While the slurry in the flask was circulated by the pump 6 at a rate of 3.5 L / min, the slurry was withdrawn from the outlet 8 at a rate of 0.1 L / min (residence time was 75 minutes).
The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried at 80 ° C. for 3 hours at 5 mmHg under reduced pressure to give 2,2-bis [@ 3,5-dibromo-4.
-(2,3-Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals had a purity of 96%, an average particle diameter of 0.2 mm, and a recovery of 95%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 25 ° C.).
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 3 The flask shown in FIG. 1 was charged with the 90% pure 2,2-bis [$ 3,5 obtained in Reference Example B.
-Dibromo-4- (2,3-dibromopropyloxy) {phenyl] propane in 50% strength by weight methylene chloride solution, methanol and the weight ratio of methylene chloride to methanol was 50:50, and in Reference Example A The obtained solid-liquid mixture in which the ratio of the seed crystal B was 33% by weight was 0.05 L / min and 0.05 L, respectively, by a metering pump.
/ Min, at a rate of 0.03 L / min for 8 hours continuously at 25 ° C.
At this temperature, the mixture was added while stirring the inside of the flask.

Twenty minutes after the start of the addition, the slurry in the flask was circulated at a rate of 3.5 L / min by the pump 6 while the slurry was withdrawn from the discharge port 8 at a rate of 0.13 L / min ( Residence time is 20 minutes). The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [｛3,5-dibromo-4- ( 2,
Crystals of 3-dibromopropyloxy) {phenyl] propane were obtained. The obtained crystals had a purity of 96%, an average particle diameter of 0.4 mm, and a recovery of 96%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 25 ° C.).
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 4 The procedure of Example 1 was repeated, except that the crystallization temperature was changed from 25 ° C. to 40 ° C. and the seed crystal B was changed to the seed crystal A. Crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane were obtained. The obtained crystals had a purity of 96%, an average particle diameter of 0.2 mm, and a recovery of 94%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 40 ° C.).
The solubility of BA-BE was 1.6 g / 100 g of solvent), and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 5 2 kg of methylene chloride, 3 kg of methanol and 2.5 kg of the seed crystal B obtained in Reference Example A were placed in a flask shown in FIG. 1 and mixed (the specific gravity of the solid-liquid mixture was 1%). .10, and the capacity is 6.8 L).

While stirring the inside of the flask, at a temperature of 25 ° C., the 90% pure 2,2-bis [５−3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) A solution of methylene chloride at a concentration of 50% by weight of [phenyl] propane and methanol were supplied at a rate of 0.02 L / min and 0.03 L / min by a metering pump, respectively.
Added continuously over time. 10 minutes after starting the addition,
While circulating the slurry in the flask at a rate of 3.5 L / min by the pump 6, the slurry was withdrawn from the outlet 8 at a rate of 0.05 L / min (residence time was 146
Minutes). The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [｛3,5-dibromo-4- ( 2,3-Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals have a purity of 95.
%, The average particle diameter is 0.3 mm, and the recovery rate is 9%.
6%.

The weight ratio of methylene chloride to methanol in the slurry was 40:60 (T at 25 ° C.).
The solubility of BA-BE was 0.2 g / 100 g of solvent), and the ratio of TBA-BE crystals in the slurry was 28 to 33% by weight.

Example 6 1.5 kg of methylene chloride, 3.5 kg of methanol and 2.5 kg of the seed crystal B obtained in Reference Example A were placed in a flask shown in FIG. Has a specific gravity of 1.04 and a capacity of 7.
2L. ).

While stirring the inside of the flask, at a temperature of 40 ° C., the 90% pure 2,2-bis [｛3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) A 50 wt% methylene chloride solution of [phenyl] propane and methanol were continuously added by a metering pump at a rate of 0.015 L / min and 0.035 L / min for 8 hours, respectively. Ten minutes after the start of the addition, 3.5 L of the slurry in the flask was pumped out by pump 6.
The slurry was withdrawn at a rate of 0.05 L / min from the withdrawal port 8 while circulating at a rate of 15 / min (residence time was 15
4 minutes). The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [｛3,5-dibromo-4- ( 2,3-Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals have a purity of 9
5%, the average particle diameter was 0.4 mm, and the recovery was 97%.

The weight ratio of methylene chloride to methanol in the slurry was 30:70 (T at 40 ° C.).
The solubility of BA-BE was 0.1 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 22 to 33% by weight.

Example 7 In a flask shown in FIG. 1, 3 kg of methylene chloride, 2 kg of methanol and 2.5 kg of seed crystal B obtained in Reference Example A were mixed and mixed (the specific gravity of this solid-liquid mixture was 1%). .20, and the capacity is 6.3 L).

While stirring the inside of the flask, at a temperature of 35 ° C., the 90% pure 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) A solution of 50% by weight of [phenyl] propane in methylene chloride and methanol were pumped at a rate of 0.06 L / min and 0.04 L / min by a metering pump, respectively.
Added continuously over time. 10 minutes after starting the addition,
While the slurry in the flask was circulated at a rate of 3.5 L / min by the pump 6, the slurry was withdrawn from the outlet 8 at a rate of 0.1 L / min (residence time was 73 minutes).
The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried at 80 ° C. for 3 hours at 5 mmHg under reduced pressure to give 2,2-bis [@ 3,5-dibromo-4.
-(2,3-Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals had a purity of 97%, an average particle diameter of 0.2 mm, and a recovery of 84%.

The weight ratio of methylene chloride to methanol in the slurry was 60:40 (T at 35 ° C.).
The solubility of BA-BE was 4.0 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 8 The procedure of Example 1 was repeated, except that 1,2-dichloroethane was used instead of methylene chloride.
Performed in the same manner as in Example 1 to give 2,2-bis [@ 3,5-
Dibromo-4- (2,3-dibromopropyloxy)
[Phenyl] propane crystals were obtained. The obtained crystals had a purity of 94%, an average particle diameter of 0.3 mm, and a recovery of 95%.

The weight ratio of 1,2-dichloroethane to methanol in the slurry was 50:50 (at 25 ° C.
Is 0.5 g / solvent 100
g), the proportion of TBA-BE crystals in the slurry was 33% by weight.

Example 9 In a flask shown in FIG. 1, 2.5 kg of toluene, 2.5 kg of methanol and 2.5 kg of a seed crystal B obtained in Reference Example A were mixed and mixed. Specific gravity is 0.92 and capacity is 8.2L
Becomes ).

While stirring the flask, at a temperature of 35 ° C., 90% pure 2,2-bis [｛3,5-dibromo-
4- (2,3-dibromopropyloxy) @phenyl]
A toluene solution having a concentration of 50% by weight of propane and methanol were respectively fed to a metering pump at 0.08 L / min.
It was added continuously at a rate of 0.05 L / min for 8 hours. Ten minutes after the start of the addition, the slurry was withdrawn from the outlet 8 at a rate of 0.13 L / min while the slurry in the flask was circulated at a rate of 3.5 L / min by the pump 6 (residence time was 73 minutes). 7-8 after starting the addition
The slurry withdrawn during the period was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)}. [Phenyl] propane crystals were obtained. The obtained crystals had a purity of 94%, an average particle diameter of 0.3 mm, and a recovery of 94%.

The weight ratio of toluene to methanol in the slurry was 50:50 (TBA at 35 ° C.)
The solubility of -BE was 1.4 g / the solvent of 100 g), and the ratio of TBA-BE crystals in the slurry was 33% by weight.

Example 10 In the flask shown in FIG.
2.5 kg of ethyl acetate, 2.5 g of diisopropyl ether
kg and 2.5 kg of the seed crystal B obtained in Reference Example A were added and mixed (the specific gravity of the solid-liquid mixture was 0.82, and the volume became 9.1 L).

While stirring the flask, at a temperature of 40 ° C., 90% pure 2,2-bis [５−3,5-dibromo-
4- (2,3-dibromopropyloxy) @phenyl]
A 50% by weight solution of propane in ethyl acetate and diisopropyl ether were continuously added for 8 hours at a rate of 0.07 L / min and 0.05 L / min by means of a metering pump. Ten minutes after the start of the addition, the slurry was withdrawn from the outlet 8 at a rate of 0.12 L / min while the slurry in the flask was circulated at a rate of 3.5 L / min by the pump 6 (residence time was 86 minutes). The slurry extracted between 7 and 8 hours after the start of the addition was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [｛3,5-dibromo-4- ( 2,
Crystals of 3-dibromopropyloxy) {phenyl] propane were obtained. The obtained crystals had a purity of 94%, an average particle diameter of 0.3 mm, and a recovery of 95%.

The weight ratio of ethyl acetate to diisopropyl ether in the slurry was 50:50 (40 ° C.
Of TBA-BE is 1.0 g / solvent 100
g), the proportion of TBA-BE crystals in the slurry was 33% by weight.

Example 11 A 4-necked 1-L flask equipped with a thermometer, stirrer and dropping funnel was charged with 2
While stirring the inside of the flask at a temperature of 5 ° C., a solid-liquid mixture comprising 67 g of methylene chloride, 67 g of methanol, and 30 g of seed crystal B obtained in Reference Example A, and 90% pure obtained in Reference Example B , 2-bis [｛3,5-dibromo-4-
225 g of a 50% strength by weight solution of (2,3-dibromopropyloxy) {phenyl] propane in methylene chloride and 113 g of methanol were continuously added via a dropping funnel over 30 minutes each. After the addition was completed, the slurry was further stirred for 30 minutes. Thereafter, the slurry is filtered,
By drying under reduced pressure at 5 mmHg at 80 ° C. for 3 hours, 2,2-bis [｛3,5-dibromo-4- (2,3
[Dibromopropyloxy) {phenyl] propane crystals were obtained. The obtained crystals had a purity of 96%, an average particle diameter of 0.5 mm, and a recovery of 95%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 25 ° C.).
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 28% by weight.

Example 12 In a four-necked 1 L flask equipped with a thermometer, a stirrer and a dropping funnel, 67 g of methylene chloride, 67 g of methanol and 30 g of the seed crystal B obtained in Reference Example A were prepared. The solid-liquid mixture was charged.

While stirring the inside of the flask, at a temperature of 25 ° C., the 90% pure 2,2-bis [５−3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Reference Example B was obtained. ) 225 g of a 50% strength by weight solution of [phenyl] propane in methylene chloride and 113 g of methanol,
The addition was continued from the dropping funnel over a period of 30 minutes each. After the addition was completed, the slurry was further stirred for 30 minutes. Thereafter, the slurry was filtered, and 80 ° C., 3 hours, 5 mm
By drying under reduced pressure with Hg, 2,2-bis [｛3,
Crystals of 5-dibromo-4- (2,3-dibromopropyloxy) {phenyl] propane were obtained. The obtained crystals had a purity of 95%, an average particle diameter of 0.4 mm, and a recovery of 95%.

Incidentally, the weight ratio of methylene chloride to methanol in the slurry was 50:50 (T
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 18 to 28% by weight.

Example 13 A 4-necked 1-L flask equipped with a thermometer, stirrer and dropping funnel was charged with 2
While stirring the inside of the flask at a temperature of 5 ° C., a solid-liquid mixture composed of 67 g of methanol and 30 g of the seed crystal B obtained in Reference Example A;
359 g of a 50% by weight methylene chloride solution of bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane and 113 g of methanol
Was added continuously from the dropping funnel over a period of 30 minutes each. After the addition was completed, the slurry was further stirred for 30 minutes.
Thereafter, the slurry was filtered, and the mixture was filtered at 80 ° C. for 3 hours for 5 hours.
By drying under reduced pressure at mmHg, crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane were obtained. The obtained crystals had a purity of 94%, an average particle diameter of 0.5 mm, and a recovery of 95%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 25 ° C.).
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 37% by weight.

Example 14 A 4-necked 1-L flask equipped with a thermometer, stirrer and dropping funnel was charged with 2
At a temperature of 5 ° C., while stirring the inside of the flask, a solid-liquid mixture composed of 60 g of methylene chloride, 120 g of methanol and 20 g of seed crystal B obtained in Reference Example A and 90% pure obtained in Reference Example B were used. 50% strength by weight solution of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane in methylene chloride 12
0 g were added continuously from the dropping funnel over 30 minutes each. After the addition was completed, the slurry was further stirred for 30 minutes. Thereafter, the slurry was filtered and dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours to give 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane. Was obtained. The obtained crystals had a purity of 95%, an average particle diameter of 0.5 mm, and a recovery of 95%.

The weight ratio of methylene chloride to methanol in the slurry was 50:50 (T at 25 ° C.).
The solubility of BA-BE was 0.7 g / the solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 25% by weight.

Example 15 The procedure of Example 1 was repeated, except that the methylene chloride solution of Reference Example C was used in place of the 50% by weight methylene chloride solution of Reference Example B. The same operation was performed to obtain bromine compound crystals. The purity of the obtained crystals is 97%, and the average particle size is 0.4%.
mm.

Example 16 In Example 11, the 50% by weight methylene chloride solution 22 obtained in Reference Example B was used.
The methylene chloride solution 2 obtained in Reference Example C was used instead of 5 g.
A bromine compound crystal was obtained in the same manner as in Example 11 except that 25 g was used. The purity of the obtained crystals was 97%, and the average particle size was 0.5 mm.

Comparative Example 1 A flask equipped with a thermometer, a stirrer and a reflux tube was charged with 240 g of methanol and 20 g of the seed crystal B obtained in Reference Example A and mixed. While stirring the flask, at a temperature of 25 ° C., the 90% pure 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl obtained in Reference Example B was obtained. ] A 50% strength by weight solution of propane in methylene chloride 12
0 g was added from the dropping funnel over 30 minutes. After the addition was completed, stirring was continued for another 30 minutes. Then, the precipitated powder was filtered and 2,2-bis [｛3,5-dibromo-
4- (2,3-dibromopropyloxy) @phenyl]
Propane powder was obtained. This was heated at 80 ° C for 3 hours,
Dry under reduced pressure at Hg. However, in this drying under reduced pressure, powder adhered to each other, resulting in a large block and partial coloring. This bromine compound
The purity was 92% and the recovery was 96%.

The weight ratio of methylene chloride to methanol in the slurry after the addition of the methylene chloride solution was 20:80.
(The solubility of TBA-BE at 25 ° C. is 0.0
2 g / solvent 100 g), and the ratio of TBA-BE crystals in the slurry was 8 to 20% by weight. Table 1 shows these results.
And Table 2.

[0124]

[Table 1]

[0125]

[Table 2]

[0126]

According to the purification method of the present invention, high purity,
A bromine compound having excellent heat stability can be obtained, and such a bromine compound is suitably used as a flame retardant for a resin.
The industrial effects are extraordinary.

[Brief description of the drawings]

FIG. 1 is an example of an apparatus for purifying a bromine compound according to the present invention.

[Explanation of symbols]

 1. Addition port 2. Addition port 3. 3. Addition port Condenser 5. Thermometer 6. Pump 7. 7. Addition port of circulated slurry 8. Slurry outlet 9 Stirrer blade 10. slurry

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI C07C 317/22 C07C 317/22

Claims (10)

[Claims] 1. A method of crystallizing and purifying a bromine compound from a crude solution containing a bromine compound represented by the following general formula (1), wherein (I) a seed crystal is present in a crystallization system, (II) a ratio of the bromine compound crystal in the slurry comprising the good solvent, the poor solvent and the crystal of the bromine compound is 10 to 50% by weight, and (III) a mixed solvent of the good solvent and the poor solvent in the slurry. A method for purifying a bromine compound, wherein the solubility of the bromine compound in water is 0.1 to 5 g / 100 g of a solvent. Embedded image (Wherein, Ar ¹ and Ar ² are the same or different aromatic hydrocarbon groups having 6 to 10 carbon atoms; Y is 1 to 3 carbon atoms)
R ¹ and R ² are the same or different and have ^{2 to} 5 carbon atoms; m and n are the same or different integers of 1 to 4; p and q are the same Alternatively, it represents a different integer of 2 or 4. ) 2. The bromine compound according to the above formula (1), wherein Ar ¹ and Ar ² are benzene; Y is a methylene group or isopropylidene group; R ¹ and R ² are an alkyl group having 2 or 3 carbon atoms; And n is 1 or 2; p and q
The method for purifying a bromine compound according to claim 1, wherein is a compound showing 2. 3. The good solvent has a bromine compound having a solubility of 1 g / g.
The method for purifying a bromine compound according to claim 1, wherein the solvent is 100 g or more. 4. The poor solvent has a bromine compound solubility of 0.0
The method for purifying a bromine compound according to claim 1, wherein the amount is 8 g / 100 g or less. 5. The bromine compound according to claim 1, wherein the good solvent is at least one selected from the group consisting of methylene chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane, cyclohexanone, ethyl acetate and toluene. Purification method. 6. The method for purifying a bromine compound according to claim 1, wherein the poor solvent is at least one selected from the group consisting of water, methanol, ethanol, i-propanol and diisopropyl ether. 7. When the value of the volume ratio of the good solvent to the poor solvent (good solvent / poor solvent) in the mixed solvent in the slurry is a, the volume ratio of the good solvent to the poor solvent in the additive component (good solvent/
The method for purifying a bromine compound according to claim 1, wherein the crude solution and the poor solvent are supplied into the slurry such that the value of the poor solvent is in the range of 0.5a to 2.0a. 8. The crude solution containing a bromine compound represented by the general formula (1) is a solution derived from a method of reacting an unsaturated bromine compound represented by the following general formula (2) with bromine. A method for purifying a bromine compound according to claim 1. Embedded image (In the formula, Ar ¹ , Ar ² , Y, m and n have the same meanings as defined in the general formula (1). Q ¹ and Q ²
Represents a C2-5 hydrocarbon group having the same or different and one or two unsaturated groups. ) 9. A method of crystallizing and continuously purifying a bromine compound from a crude solution containing a bromine compound represented by the above general formula (1), wherein (I) the crude solution is purified Continuously supplying a solvent containing a crystal of the bromine compound together with a solvent into a container containing the slurry to precipitate the bromine compound in the slurry with stirring; (II) in this case, a good solvent and a poor solvent in the container; And the ratio of the bromine compound crystals in the slurry of the bromine compound crystals is 10 to 50% by weight, and (III) at that time, based on the mixed solvent of the good solvent and the poor solvent in the slurry in the container. The solubility of the bromine compound is from 0.1 to 5 g / 100 g of a solvent, and (IV) the slurry is continuously taken out from the vessel and crystal particles of the bromine compound are separated from the slurry. A continuous purification method for bromine compounds. 10. The method for continuously purifying a bromine compound according to claim 9, wherein a part of the slurry continuously taken out of the vessel is circulated in the vessel.