JPH11292816A - Purification of bromine compound - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject high-purity compound excellent in heat stability by adding a bromine compound in melted state, a good solvent and a poor solvent to a solid-liquid mixture comprising the poor solvent and seed crystal and mixing these components. SOLUTION: (A) A bromine compound of the formula [(m), (n), (p) and (q) are each 1-6; Ar<1> and Ar<2> are each a 5-16C aromatic hydrocarbon; Y is methylene or the like; R<1> and R<2> are each a 2-6C saturated hydrocarbon] in melted state [e.g. 2,2-bis [3,5-dibromo-4-(2,3-dibromopropyloxy)]phenyl}propane], (B) a good solvent [a solvent capable of dissolving >=5 wt.% bromine compound at 20 deg.C] (e.g. methylene chloride) and (C) a poor solvent [a solvent incapable of dissolving >=2 wt.% bromine compound at 20 deg.C] (e.g. methanol) are added to (D) a solid-liquid mixture comprising the poor solvent and seed crystal and these components are mixed to provide slurry comprising the good solvent, the poor solvent and bromine compound crystal and containing the crystal in a ratio of 0.01-70 wt.%.

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 heat stability (without blocking or coloring).

[0002]

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

[0003] If such a bromine compound contains a by-product produced in the course of its production, the by-product adversely affects the thermal stability, and 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.

Japanese Patent Application Laid-Open No. 55-111429 discloses a method in which an aromatic hydrocarbon solution of TBA-BE is added 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. There is a need for a purification method for obtaining a bromine compound having excellent stability.

[0012]

SUMMARY OF THE INVENTION The present inventors have conducted intensive studies with the aim of providing a purification method for obtaining a bromine compound having improved purity and excellent thermal stability. , A good solvent and a poor solvent were added to a solid-liquid mixture composed of a poor solvent and a seed crystal, and by mixing, it was found that a bromine compound having high purity and excellent thermal stability could be recovered, and the present invention was reached. .

[0013]

According to the present invention, there is provided a method for purifying a bromine compound from a molten bromine compound represented by the following formula (1): The poor solvent is added to and mixed with a solid-liquid mixture composed of the poor solvent and the seed crystal to form a slurry composed of the good solvent, the poor solvent and the crystal of the bromine compound, and the ratio of the crystals in the obtained slurry is 0.1%. A method for purifying a bromine compound, which is characterized in that the amount is from 01 to 70% by weight.

[0014]

Embedded image

(Where m, n, p, and q are integers of 1 to 6, Ar ¹ and Ar ² may be the same or different, and are aromatic hydrocarbon groups having 5 to 16 carbon atoms.) Y is a kind selected from methylene, propylene, isopropylidene, isopropylidene, cyclohexylidene, sulfone, ketone and a single bond, and R ¹ and R ² are each a saturated hydrocarbon group having 2 to 6 carbon atoms. )

The bromine compound used in the present invention is represented by the above formula (1), wherein m, n, p and q are integers of 1 to 6, preferably 1 to 2, and Ar ¹ and Ar ² may be the same or different and is an aromatic hydrocarbon group having 5 to 16 carbon atoms, preferably a phenyl group, a tolyl group, a xylyl group or a naphthyl group, and Y is methylene, propylene, isopropylidene, isobutylidene, cyclohexyl. Siliden,
It is one kind selected from sulfone, ketone and single bond, preferably one kind selected from methylene, isopropylidene, isobutylidene, cyclohexylidene, sulfone and single bond, and R ¹ and R ² each have 2 carbon atoms.
To 6 saturated hydrocarbon groups, preferably an ethyl group, a propyl group, an isopropyl group, a butyl group and an isobutyl group.

As such a bromine compound, 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.

In the present invention, the desired high-purity bromine compound is obtained by adding and mixing the molten bromine compound, good solvent and poor solvent to a solid-liquid mixture comprising a poor solvent and seed crystals. Can be obtained.

In the purification method of the present invention, a bromine compound in a molten state is used. The melting temperature differs depending on the bromine compound used. For example, when the bromine compound is 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane, it is preferable. Is 110 ° C to 150 ° C, more preferably 115 ° C to 145.
It is desirable to use what is heated to 120 ° C, particularly preferably 120 ° C to 140 ° C. The bromine compound is bis [｛3
In the case of 5-dibromo-4- (2,3-dibromopropyloxy) {phenyl] methane, the temperature is preferably from 90C to
It is desirable to use one heated to 130 ° C, more preferably 95 ° C to 125 ° C, particularly preferably 100 ° C to 120 ° C. Bis [｛3,5-dibromo-4- (2,
In the case of 3-dibromopropyloxy) {phenyl] sulfone, it is preferably 170C to 210C, more preferably 175C to 205C, and particularly preferably 180C to 2C.
It is desirable to use one heated to 00 ° C. Melting the bromine compound within a range not exceeding a temperature higher by 30 ° C. than the melting point of the bromine compound is preferably employed because there is no risk of decomposition of the bromine compound.

The good solvent used in the present invention includes 20
A good solvent capable of dissolving the bromine compound at a concentration of 5% or more at a temperature of 5 ° C., for example, methylene chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane, acetone, methyl isobutyl ketone, diethyl ketone, Cyclohexanone, dioxane, ethyl acetate, butyl acetate, toluene, xylene, benzene, dimethylformamide, dimethylacetamide, dimethylsulfoxide and the like, methylene chloride, chloroform,
1,2-Dichloroethane, 1,1-dichloroethane, cyclohexanone, ethyl acetate, toluene and dimethylformamide are preferred, methylene chloride, chloroform, 1,2-dichloroethane and 1,1-dichloroethane are more preferred, and methylene chloride is particularly preferred. Can be These solvents are used alone or in combination of two or more.

As the poor solvent used in the present invention, 20
The bromine compound cannot be dissolved at a concentration of 2% or more at a concentration of 2% or more at a temperature of 0 ° C. Diethyl ether, dipropyl ether, diisopropyl ether and n-pentane, n-hexane, saturated hydrocarbons having 5 to 10 carbon atoms such as n-octane and the like, and water, methanol, ethanol, i-propanol and diisopropyl ether Preferably, water, methanol, ethanol and i-propanol are more preferable, and methanol is particularly preferably used. These poor solvents are used alone or in combination of two or more.

The solid-liquid mixture of the present invention is before the addition of the bromine compound in a molten state, a good solvent and a poor solvent, and comprises a poor solvent and seed crystals.

As the poor solvent, those similar to the above-mentioned poor solvents are used, and the seed crystal preferably has a purity of 90% or more. As the seed crystal, the same compound as the bromine compound in a molten state to be used is preferably used. By using a seed crystal, the generation of bromine compound crystals from the molten bromine compound is smoothed, a high-purity bromine compound with less impurities is obtained, and the generation of microcrystals is suppressed. The crystals of the bromine compound have a uniform particle size.

In the solid-liquid mixture, the proportion of the seed crystals in the solid-liquid mixture is preferably 0.01 to 70% by weight,
0.1 to 60% by weight is more preferable, 1 to 55% by weight is more preferable, and 5 to 50% by weight is particularly preferable. When the ratio of the seed crystal is lower than 0.01% by weight, the seed crystal does not function sufficiently, which is not preferable. When the ratio is higher than 70% by weight, the production efficiency of the bromine compound is lowered, which is not preferable.

In the present invention, the bromine compound in a molten state, a good solvent and a poor solvent are added to the solid-liquid mixture and mixed to crystallize the bromine compound. Here, the bromine compound in a molten state, a good solvent and a poor solvent are added to a solid-liquid mixture, and the mixture is referred to as a slurry. The slurry is
It consists of a crystal of a good solvent, a poor solvent and a bromine compound, and more specifically, a solution part of a solvent of a good solvent and a poor solvent in which impurities and an uncrystallized bromine compound are dissolved, and a crystal of a bromine compound containing some impurities. And consists of parts. Such good and poor solvents are the same as the good and poor solvents described above. Further, such a bromine compound crystal includes both a seed crystal in the solid-liquid mixture and a bromine compound crystal generated from the molten bromine compound. In addition, a part of the generated crystal of the bromine compound itself has a function as a seed crystal.

In the slurry comprising the crystals of the good solvent, the poor solvent and the bromine compound, the ratio of the crystals of the bromine compound in the slurry is 0.01 to 70% by weight.
It is preferably from 1 to 60% by weight, more preferably from 1 to 55% by weight, even more preferably from 5 to 50% by weight. Here, the ratio of the crystals of the bromine compound is a ratio to the weight of the entire slurry (including the good solvent, the poor solvent, the crystals of the bromine compound, the bromine compound dissolved in the solvent, and the impurities, as described above). is there. If the ratio of such crystals is lower than 0.01% by weight, the production efficiency of the bromine compound is lowered, which is not preferable. It is difficult to obtain a compound, which is not preferable. Further, regarding the ratio of the bromine compound crystals in the slurry, the bromine compound in a molten state, a good solvent and a poor solvent were added to the solid-liquid mixture, and mixing was started. Bromine compounds,
This means that the above ratio is maintained until the addition of the good solvent and the poor solvent is completed.

In the present invention, the method of adding the bromine compound, the good solvent and the poor solvent in the molten state to the solid-liquid mixture is not particularly limited, but the bromine compound, the good solvent and the poor solvent in the molten state are added. Preferably, a method of continuously adding a fixed amount by using a pump or a dropping funnel is preferably used. The bromine compound in a molten state;
It is also possible to adopt a continuous method of extracting a part of the slurry in the container outside the container while adding a good solvent and a poor solvent,
A part of the slurry drawn out of the container can be circulated.

In the method of the present invention, the bromine compound in a molten state, a good solvent and a poor solvent are added to the solid-liquid mixture, and when the bromine compound is crystallized, the solvent evaporates and the It is preferable to control so as not to scatter. The temperature at which the bromine compound is crystallized is not particularly limited, but is preferably a temperature not exceeding the boiling point of the solvent (mixed solvent of a good solvent and a poor solvent) in the slurry,
A range of 50 ° C, more preferably a range of 25 to 50 ° C, can be adopted. When methylene chloride, which is suitable as a good solvent, is used, the temperature is preferably in the range of 5 to 40C, more preferably 25 to 40C. When such a method is employed, a good solvent is present in the slurry, and crystallization proceeds gradually, so that a high-purity bromine compound is easily obtained, and the control of the morphology (particle size) of the crystal is prevented. It has the advantage of being easier. 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.

When a good solvent solution known in the prior art is added to a mixture of a seed crystal and a poor solvent, a bromine compound precipitates rapidly, it is difficult to remove impurities, and the resulting bromine compound has low purity. On the other hand, the purification method of the present invention provides a bromine compound in a molten state,
It is considered that since the good solvent and the poor solvent are added, the ratio between the good solvent and the poor solvent changes slowly, and the crystallization proceeds slowly, so that the impurities are efficiently extracted.

In a preferred embodiment of the present invention, the bromine compound is 2,2-bis [@ 3,5-dibromo-4-.
(2,3-dibromopropyloxy) @phenyl] propane, and when the good solvent in the slurry is methylene chloride and the poor solvent is methanol, a molten bromine compound, a good solvent and a poor solvent are added. The ratio of methylene chloride to methanol in the slurry after the weighting is 30:
It is preferably 70 to 70:30.

Crystals precipitated by the method of the present invention are:
Separation by filtration, centrifugation, or the like, and drying by a known method can give a purified bromine compound.

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. When the average particle size is smaller than 0.1 mm, the handleability becomes poor, and the working environment is deteriorated due to scattering of dust, which is not preferable.
If the average particle size is larger than 0.9 mm, the dispersibility of the bromine compound as a flame retardant in a resin is poor, which is not preferable.

The bromine compound obtained by the purification method of the present invention is useful as a flame retardant for resins, and particularly, ABS.
It is suitable as a flame retardant for resins, styrene resins and polyolefin resins.

[0034]

The present invention will be described below in detail with reference to examples. The following methods were used for measuring the purity, the average particle size, and the ratio of the crystals in the slurry. (1) Purity analysis Purity was measured by high performance liquid chromatography.
It carried out by the method of detecting the absorption of 80 nm. (2) Average particle size Samples were prepared at 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) Ratio 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.

[Preparation Example 1] 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane having a purity of 93% 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).

Preparation Example 2 Hot air circulating drying of 130% of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane having a purity of 90%. The mixture was heated for 1 hour by a machine to be melted.

Example 1 67 g of methanol and 30 g of the seed crystal B obtained in Preparation Example 1 were placed in a 1 L four-necked flask equipped with a thermometer, a stirrer and a dropping funnel, and mixed (solid-liquid mixing). (The ratio of the seed crystal B in the body is 31% by weight.) While stirring 97 g of this solid-liquid mixture, 25 ° C.
At a temperature of 180 g of the molten 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane obtained in Preparation Example 2, 180 g of a methylene chloride solution and methanol 113 g were added in 30 minutes each from a separate dropping funnel. After completion of the addition, stirring was continued for another 30 minutes (at this time, the ratio of crystals in the slurry was 35% by weight, and the weight ratio of methylene chloride to methanol in the slurry was 50:50). Thereafter, the slurry was filtered to take out a crystal, and the crystal was taken out at 80 ° C.
The crystals were dried under reduced pressure at 5 mmHg for 3 hours to obtain crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane. The obtained crystal has a purity of 96% and an average particle diameter of 0.7 mm,
The recovery was 95%.

Example 2 72 g of methanol and 41 g of the seed crystal A obtained in Preparation Example 1 were placed in a 1-L four-necked flask equipped with a thermometer, a stirrer and a dropping funnel, and mixed (solid-liquid mixing). The proportion of seed crystal A in the body is 36% by weight). While stirring 113 g of the solid-liquid mixture, 25 g
At a temperature of 90 ° C., 91 g of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane obtained in Preparation Example 2, 91 g of methylene chloride and methanol 140 g were added in 30 minutes each from a separate dropping funnel. After completion of the addition, stirring was further continued for 30 minutes (at this time, the ratio of crystals in the slurry was 29% by weight, and the weight ratio of methylene chloride to methanol in the slurry was 30:70). Thereafter, the slurry was filtered to take out a crystal, and the crystal was taken out at 80 ° C. for 3 hours.
The crystals were dried under reduced pressure at 5 mmHg to obtain crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane. The obtained crystals have a purity of 95%, an average particle diameter of 0.6 mm, and a recovery rate of 9%.
7%.

Example 3 200 g of methanol and 160 g of the seed crystal A obtained in Preparation Example 1 were placed in a three-liter four-necked flask equipped with a thermometer, a stirrer and a dropping funnel.
(The ratio of the seed crystal A in the solid-liquid mixture was 4%).
4% by weight). While stirring 360 g of the solid-liquid mixture,
At a temperature of 35 ° C., the melted 2,2 obtained in Preparation Example 2
850 g of -bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane, 850 g of methylene chloride and 244 g of methanol were added from separate dropping funnels for 60 minutes. After completion of the addition, stirring was further continued for 30 minutes (at this time, the ratio of crystals in the slurry was 33% by weight, and the weight ratio of methylene chloride to methanol in the slurry was 66:34). Thereafter, the slurry was filtered to take out a crystal, and the crystal was taken out at 80 ° C.
After drying under reduced pressure at 5 mmHg for 3 hours, crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane were obtained. The obtained crystal has a purity of 96% and an average particle diameter of 0.3 mm,
The recovery was 75% (the remaining slightly more than 20% was dissolved in the filtrate, and the filtrate was cooled and allowed to stand to obtain a solid having a purity of 92%).

Example 4 A volume 5 with an outlet at the bottom of the vessel fitted with a thermometer, stirrer and dropping funnel
In a 00 mL four-necked flask, 200 g of methanol and 160 g of the seed crystal B obtained in Preparation Example 1 were put and mixed (the proportion of the seed crystal B in the solid-liquid mixture was 44% by weight). While stirring 360 g of the solid-liquid mixture, the 2,2-bis [@ 3,5-dibromo-4- (2,3-dibromopropyloxy) -2 ) {Phenyl] propane 850 g, methylene chloride 850 g and methanol 244 g were added from separate dropping funnels for 60 minutes each. After the start of addition, 7
After being separated, the outlet was opened and the slurry was poured into 32.4.
g / min, and was continuously withdrawn into a beaker having a volume of 3 L (the ratio of crystals in this slurry was 33% by weight,
The weight ratio of methylene chloride to methanol in the slurry is 6
6:34). After completion of the addition, the slurry extracted into a beaker was filtered to take out a crystal, which was dried at 80 ° C. for 3 hours under reduced pressure of 5 mmHg to give 2,2-bis [｛3,5.
-Dibromo-4- (2,3-dibromopropyloxy) {phenyl] propane was obtained as crystals. The obtained crystals had a purity of 98% and an average particle diameter of 0.7 mm.

Example 5 The procedure of Example 1 was repeated except that the seed crystal B was used.
Is replaced with seed crystal A, and the crystallization temperature is changed from 25 ° C. to 40 ° C.
In the same manner as in Example 1 except for changing to, 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 0.4 mm, and a recovery of 93%.

Example 6 In a 1 L four-necked flask equipped with a thermometer, a stirrer and a dropping funnel, 67 g of ethanol and 30 g of the seed crystal B obtained in Preparation Example 1 were put and mixed (solid-liquid mixing). (The ratio of the seed crystal B in the body is 31% by weight.) While stirring 97 g of this solid-liquid mixture, 25 ° C.
At a temperature of 120 g of the melted 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane obtained in Preparation Example 2 and toluene 2
80 g and 213 g of ethanol were added from separate dropping funnels each for 30 minutes (at this time, the proportion of crystals in the slurry was 20% by weight). After the addition was completed, stirring was continued for another 30 minutes. Then, this slurry was filtered,
The crystal was taken out, and this was heated at 80 ° C. for 3 hours at 5 mmHg
And dried 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 0.4 mm, and a recovery of 93%.

Example 7 67 g of ethanol and 30 g of the seed crystal A obtained in Preparation Example 1 were placed in a 1 L four-necked flask equipped with a thermometer, a stirrer, and a dropping funnel, and mixed (solid-liquid mixing). The proportion of seed crystal A in the body is 31% by weight). While stirring 97 g of this solid-liquid mixture, 40 ° C.
At the temperature of 120 g of the molten 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane obtained in Preparation Example 2, 120 g of 1,2-dichloroethane And 213 g of ethanol were added over 30 minutes from separate dropping funnels (at this time, the ratio of crystals in the slurry was 19% by weight). After the addition was completed, stirring was continued for another 30 minutes. Thereafter, the slurry was filtered to take out a crystal, and the crystal was taken out at 80 ° C., 3
Drying under reduced pressure at 5 mmHg for 2,2-bis [２，3,
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 91%.

Example 8 A 1 L four-necked flask equipped with a thermometer, stirrer and dropping funnel was charged with 67 g of water.
Then, 30 g of the seed crystal B obtained in Preparation Example 1 was added and mixed (the ratio of the seed crystal B in the solid-liquid mixture was 31% by weight).
While stirring 97 g of this solid-liquid mixture, at a temperature of 25 ° C., the melted 2,2-bis [｛3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Preparation Example 2 was obtained. ) 180 g of [phenyl] propane, 180 g of dimethylformamide and 113 g of water were added from separate dropping funnels each for 30 minutes. After completion of the addition, stirring was further continued for 30 minutes (at this time, the ratio of crystals in the slurry was 36% by weight). Thereafter, the slurry was filtered to take out a crystal, and the crystal was taken out at 80 ° C. for 3 hours and 5 mm
The crystals were dried under reduced pressure at Hg to obtain crystals of 2,2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane. The obtained crystals have a purity of 95.
%, The average particle diameter is 0.3 mm, and the recovery rate is 97%.
Met.

Example 9 67 g of diisopropyl ether and 30 g of the seed crystal A obtained in Preparation Example 1 were placed in a 1 L four-necked flask equipped with a thermometer, a stirrer and a dropping funnel, and mixed (solid-liquid). The proportion of seed crystal A in the mixture is 31% by weight). While stirring 97 g of the solid-liquid mixture, at a temperature of 40 ° C., the melted 2,2-bis [｛3,5-dibromo-4- (2,3-dibromopropyloxy) obtained in Preparation Example 2 was obtained. )｝ Phenyl] propane 120
g, 280 g of ethyl acetate and 213 g of diisopropyl ether were added over 30 minutes from separate dropping funnels. After completion of the addition, stirring was further continued for 30 minutes (at this time, the ratio of crystals in the slurry was 19% by weight). Thereafter, the slurry was filtered to take out a crystal, which was dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours.
Crystals of bis [{3,5-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 91%.

Comparative Example 1 A flask equipped with a thermometer, a stirrer and a reflux tube was charged with 180 g of methanol and 20 g of the seed crystal B obtained in Preparation Example 1, and mixed. While stirring the inside of the flask, at a temperature of 25 ° C., a purity of 90%
2,2-bis [{3,5-dibromo-4- (2,3-
50 of dibromopropyloxy) {phenyl] propane
120 g of a weight% concentration methylene chloride solution 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,
A powder of 2-bis [{3,5-dibromo-4- (2,3-dibromopropyloxy)} phenyl] propane was obtained. This was dried under reduced pressure at 5 mmHg at 80 ° C. for 3 hours. However, in this drying under reduced pressure, powder adhered to each other, resulting in a large block and partial coloring. This bromine compound has a purity of 92%,
The recovery was 96%. The results are shown in Tables 1 and 2.

[0047]

[Table 1]

[0048]

[Table 2]

[0049]

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.

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Claims (5)

[Claims] In a method for purifying a bromine compound from a bromine compound in a molten state represented by the following formula (1), the bromine compound in a molten state, a good solvent and a poor solvent are combined with a solid solvent comprising a poor solvent and a seed crystal. Add to the liquid mixture, mix, good solvent,
A slurry comprising crystals of the poor solvent and the bromine compound is used, and the ratio of crystals in the obtained slurry is 0.01 to 7
A method for purifying a bromine compound, which is 0% by weight. Embedded image (Where m, n, p, and q are integers of 1 to 6;
r ¹ and Ar ² may be the same or different, and have 5 to 5 carbon atoms.
16 is an aromatic hydrocarbon group, Y is a kind selected from methylene, propylene, isopropylidene, isobutylidene, cyclohexylidene, sulfone, ketone and a single bond, and R ¹ and R ² each have 2 to 6 carbon atoms. Is a saturated hydrocarbon group. ) 2. A good solvent is methylene chloride, chloroform, 1,2-dichloroethane, 1,1-dichloroethane, acetone, methyl isobutyl ketone, diethyl ketone, cyclohexanone, dioxane, ethyl acetate, butyl acetate, toluene, xylene, benzene. 2. The method for purifying a bromine compound according to claim 1, which is at least one solvent selected from the group consisting of dimethylformamide, dimethylacetamide and dimethylsulfoxide. 3. The poor solvent comprises water, a saturated monohydric alcohol having 1 to 5 carbon atoms, ethylene glycol, glycerin, diethyl ether, diisopropyl ether and 5 to 5 carbon atoms.
The method for purifying a bromine compound according to claim 1, which is at least one solvent selected from the group consisting of 10 saturated hydrocarbons. 4. The method for purifying a bromine compound according to claim 1, wherein the bromine compound is represented by the following formula (2). Embedded image (Where m, n, p, and q are integers of 1 to 2;
r ¹ and Ar ² may be the same or different and are a phenyl group, a tolyl group, a xylyl group or a naphthyl group;
Is a kind selected from methylene, isopropylidene, isobutylidene, cyclohexylidene, sulfone and single bond, and R ¹ and R ² are each a kind selected from ethyl group, propyl group, isopropyl group, butyl group and isobutyl group . ) 5. The bromine compound is 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-
The method for purifying a bromine compound according to claim 1, which is a kind of compound selected from 4,4 '-(1,2-dibromoethyloxy)｝ biphenyl.