JP2890846B2 - Method for separating and recovering bis (3,5-dibromo-4-dibromopropoxyphenyl) propane - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

In the present invention, bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] propane (hereinafter abbreviated as TBA-BP) was obtained by its production process. The present invention relates to a method of separating and collecting fine powder from a solution.

[0002] TBA-BP is useful as a flame retardant such as polyolefin resin.
It is extremely useful as a flame retardant such as polystyrene and the like in JP-A-60-240750 and JP-A-61-25225.
No. 6, Publication No. 6, etc.

[0003]

2. Description of the Related Art Generally, bis (4-allyloxy-3,5-dibromophenyl) propane (hereinafter abbreviated as TBA-BA) is used as a raw material for TBA-BP.
It is produced by dissolving A-BA in a halogenated hydrocarbon solvent and then reacting with bromine. Therefore, the generated TBA-B
P is obtained as a solution of a halogenated hydrocarbon solvent which is a good solvent. As a method of separating and recovering TBA-BP as a powder from the TBA-BP solution, a method of evaporating and removing the halogenated hydrocarbon solvent from the TBA-BP solution, followed by crystallization through a purification step such as recrystallization, or , TBA-
The BP solution is converted into a solvent having a low TBA-BP solubility,
A method of reprecipitation in a poor solvent is known (Japanese Patent Laid-Open No. Sho 4
9-125348, JP-A-55-111429, JP-B-57-289, etc.).

However, in the recrystallization method, since the recrystallization is performed after the reaction solvent is once distilled off, the operation is very complicated. On the other hand, in the recrystallization method, a large amount of seed crystals is added or added. There was a disadvantage that TBA-BP could be obtained as a resinous material without using a special device having a strong shearing force. In both methods, the filtrate after reprecipitation was added with T
Since BA-BP dissolves, the recovery is not quantitative, and the obtained crystals also have a problem of low quality (low melting point, coloring, etc.), so that they are still sufficiently satisfactory as an industrial method. Was not.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a method for separating and recovering TBA-BP as powder, which has heretofore been complicated in the production process and has problems in quality.
It is to provide an industrial method that is economically advantageous and simplifies conventional processes.

[0006]

Means for Solving the Problems In view of the above situation, the present inventors have proposed a simple reprecipitation method to obtain high-quality TBA-
The present inventors have conducted intensive studies on the method of separating and recovering BP as fine powder, and found that a poor solvent having a boiling point higher than that of a good solvent was dropped into a TBA-BP solution with stirring, and after the dropping was completed, a good solvent was immediately distilled. Not only enables the separation and recovery of fine powder TBA-BP in a short time,
Furthermore, the obtained finely powdered TBA-BP was found to be of high quality, and the present invention was completed.

That is, the gist of the present invention is that TBA-BA
In the method of separating and recovering the TBA-BP produced by the bromination reaction as a fine powder, a poor solvent having a boiling point higher than that of a good solvent is added to a solution of TBA-BP dissolved in a good solvent obtained in the production process. A method for separating and recovering TBA-BP, which comprises dropping, and after completion of dropping, collecting TBA-BP as fine powder dispersed in a poor solvent while distilling off a good solvent.

In the method of the present invention, since a large amount of seed crystals are not added or a special device having a strong shearing force is not used, not only can TBA-BP be separated and recovered easily, but also good distillation can be achieved. Since the solvent is distilled off, TBA-BP can be quantitatively recovered. As a result, the product cost is lower and the treatment of the filtrate is easier,
It can be said that this method is very advantageous industrially.

Hereinafter, the method of the present invention will be described in detail.

[0010]

The reaction for producing TBA-BP by using bromine with TBA-BA as a raw material in the method of the present invention can be explained using the following reaction formula.

[0011]

Embedded image The organic solvent of the TBA-BP solution used in the method of the present invention refers to a good solvent that dissolves TBA-BP,
A halogenated hydrocarbon which is inert in the bromination reaction of A is selected.

Examples include carbon tetrachloride, chloroform, methylene chloride, dichloroethane, trichloroethane, tetrachloroethane and the like.

The concentration of the TBA-BP solution is not particularly limited, but is usually selected from about 5 to 50% by weight.

The poor solvent used in the method of the present invention includes alcohols such as methanol, ethanol, n-propanol and isopropanol, ketones such as acetone and methyl ethyl ketone, and ethers such as dipropyl ether and diisopropyl ether. , Pentane, hexane,
And saturated aliphatic hydrocarbons such as cyclohexane. These may be used alone or in combination.

The amount of these poor solvents used for the separation and recovery of TBA-BP is usually 1 to 20 times, preferably 2 to 10 times the volume of the good solvent in the TBA-BP solution. When the amount of the poor solvent is less than the equivalent amount of the good solvent in the TBS-BP solution, stirring after the precipitation of the TBS-BP is difficult, and when the amount exceeds 20 times, it is not economical.

In the method of the present invention, it is necessary that the boiling point of the poor solvent is higher than that of the good solvent. After completion of the addition of the poor solvent, the boiling point of the poor solvent is usually 5 ° C. or more, preferably 10 ° C. or more higher than that of the good solvent in order to carry out the distillation of the good solvent. Therefore, a combination of a good solvent and a poor solvent having such a boiling point is selected, and typically, methylene chloride (bp 39.8 ° C.)-Methanol (bp 6
4.5 ° C.), methylene chloride (bp 39.8 ° C.)-Isopropanol (bp 82.4 ° C.), chloroform (bp 61.2 ° C.)-Methyl ethyl ketone (b.p.
p. 79.6 ° C.), methylene chloride (bp 39.8)
° C) -diisopropyl ether (bp 68.5)
° C), carbon tetrachloride (bp 76.8 ° C) -heptane (bp 98.4 ° C), and the like. Particularly preferably, methylene chloride (bp 39.8 ° C.)-Isopropanol (b.p.
p. 82.4 ° C.).

When the poor solvent is dropped, vigorous stirring or the like is not required, and it is only necessary that appropriate stirring is performed.
The distillation of the good solvent carried out in the method of the present invention is usually carried out under normal pressure, but can be carried out under reduced pressure.
As the distillation temperature, a temperature at which the TBA-BP does not melt and consolidate to maintain a slurry state is selected.
Below the melting point of BP, ie below 110 ° C., preferably below 100 ° C.
It is necessary to be less than or equal to ° C.

The removal rate of this good solvent by distillation is as follows:
Higher is desirable, and specifically, it is preferable to remove 60% or more. In this case, the recovery of TBA-BP is almost quantitative. Conversely, when the removal rate of the good solvent is less than 60%, not only the resinous TBA-BP partially remains,
It is not preferable because the recovery rate of TBA-BP decreases.
A poor solvent may be added before, during or after the distillation of the good solvent to adjust the slurry concentration.

The obtained TBA-BP slurry solution is
Can be easily separated by conventional methods. For example, separation can be performed by centrifugation, suction filtration, spray drying, or the like. The TBA-BP obtained by these methods is a white fine powder having a high melting point, and can be used as a high-quality TBA-BP as a flame retardant such as polyolefin.

[0020]

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

Example 1 A 3 liter flask having a thermometer, a stirring blade and a condenser was charged with methylene chloride;
g (1323 ml) and TBA-BA; 875 g (1.
4 mol) and bromine; 469 g (2.9 mol)
Was dropped at 24 to 27 ° C. over 1 hour, and after dropping, aging was performed at that temperature for 1 hour.

After the reaction, the remaining bromine is reduced with an aqueous solution of sodium hydrogen sulfite, and further washed with water to obtain TBA-BP;
95 g (1.37 mol), methylene chloride; 1701 g
(1280 ml); 3010 g (2009 m
1) was obtained. The solution was analyzed by liquid chromatography, and as a result, the yield of TBA-BP was 9
8.0%, TBA-BA conversion was 100%.
Hereinafter, this solution is referred to as a processing solution. From this processing solution, TB
A-BP; 185 g (196 mmol), methylene chloride; a solution containing 243 g (183 ml); 430 g (2
87 ml) was used for the next separation and recovery.

428 g (549 ml) of isopropanol was dropped into the above-mentioned treatment solution at room temperature with stirring over 10 minutes, and after completion of the dropping, a residue containing methylene chloride as a main component at a temperature of 55 to 82 ° C. under normal pressure. 330 g were distilled off. At the end of the distillation, the precipitated TBA-BP became fine powder and was uniformly dispersed in the poor solvent. The distillate fraction was analyzed by gas chromatography.
It contained 231 g of methylene chloride, and the recovery of methylene chloride was 95.1%.

Thereafter, the mixture is cooled to room temperature with stirring,
After suction filtration of the slurry solution of -BP and washing with water,
Drying yielded 188.8 g of white fine powder crystals. The obtained TBA-BP crystal was analyzed by liquid chromatography, and as a result, the purity of TBA-BP was 9
The recovery rate of 7.9% and TBA-BA was 99.9%. Also, as a result of measuring the melting point of this crystal, 111 to 1
13 ° C.

(Example 2) A solution containing 185 g (196 mmol) of TBA-BP and 243 g (183 ml) of methylene chloride from the treatment solution prepared in Example 1: 430
g (287 ml) was withdrawn, and at room temperature, methanol; 434 g (549 ml) was added dropwise with stirring over 13 minutes.
After the completion of the dropwise addition, 290 g of a fraction containing methylene chloride as a main component was distilled off under normal pressure at a temperature of 50 to 64 ° C. At the end of the distillation, the precipitated TBA-BP became fine powder and was uniformly dispersed in the poor solvent. The distillate fraction was analyzed by gas chromatography and found to contain 170 g of methylene chloride; the recovery of methylene chloride was 70.0%.

Thereafter, the mixture is cooled to room temperature with stirring,
After suction filtration of the slurry solution of -BP and washing with water,
Drying yielded 188.6 g of white fine powder crystals. The obtained TBA-BP crystal was analyzed by liquid chromatography, and as a result, the purity of TBA-BP was 9
The recovery rate of 7.6% and TBA-BA was 99.5%. Also, as a result of measuring the melting point of this crystal, 110 to 1
14 ° C.

(Example 3) A solution containing 185 g (196 mmol) of TBA-BP and 243 g (183 ml) of methylene chloride from the treatment solution prepared in Example 1;
g (287 ml) was taken out, and the solvent was replaced with chloroform to give a chloroform solution of the same volume. Heptane; 622 g (915 ml) was added dropwise at room temperature with stirring for 15 minutes. At a temperature of ° C., 287 g of a fraction containing chloroform as a main component was distilled off.
At the end of the distillation, the precipitated TBA-BP became fine powder and was uniformly dispersed in the poor solvent. The distillate fraction was analyzed by gas chromatography.
Chloroform: 218 g, and the recovery of chloroform was 80.0%.

Thereafter, the mixture was cooled to room temperature with stirring,
After suction filtration of the slurry solution of -BP and washing with water,
Drying yielded 189.4 g of white fine powder crystals. The obtained TBA-BP crystal was analyzed by liquid chromatography, and as a result, the purity of TBA-BP was 9
The recovery rate of 7.4% and TBA-BA was 99.7%. Also, as a result of measuring the melting point of this crystal, 110 to 1
13 ° C.

(Example 4) A solution containing 185 g (196 mmol) of TBA-BP and 243 g (183 ml) of methylene chloride from the treatment solution prepared in Example 1;
g (287 ml), diisopropyl ether; 527 g (732 ml)
After completion of the dropwise addition, 295 g of a fraction containing methylene chloride as a main component was distilled off under normal pressure at a temperature of 50 to 68 ° C. At the end of the distillation, the precipitated TBA-BP became fine powder and was uniformly dispersed in the poor solvent. The distillate was analyzed by gas chromatography, and as a result, it was found to contain 221 g of methylene chloride, and the recovery of methylene chloride was 90.9%.

Thereafter, the mixture is cooled to room temperature with stirring,
After suction filtration of the slurry solution of -BP and washing with water,
Drying yielded 189.5 g of white fine powder crystals. The obtained TBA-BP crystal was analyzed by liquid chromatography, and as a result, the purity of TBA-BP was 9
The recovery rate of 7.3% and TBA-BA was 99.7%. Also, as a result of measuring the melting point of this crystal, 110 to 1
14 ° C.

(Comparative Example 1) A solution containing 185 g (196 mmol) of TBA-BP, 243 g (183 ml) of methylene chloride, and 430 from the treatment solution produced in Example 1;
g (287 ml) was extracted, and 714 g (915 ml) of isopropanol was added dropwise with stirring at room temperature over 20 minutes. After the completion of dropping, TBA-BP was a slurry solution containing a large amount of resinous material. The obtained crystals were subjected to suction filtration, washed with water, and dried to obtain 180.6 g of yellow crystals containing a large amount of resinous substances. The obtained TBA-
As a result of analyzing the BP crystal by liquid chromatography, the purity of TBA-BP was 96.8%,
The recovery of A-BP was 94.5%. The melting point of the crystal was measured and found to be 93 to 102 ° C.

(Comparative Example 2) A solution containing 185 g (196 mmol) of TBA-BP, 243 g (183 ml) of methylene chloride from the treatment solution prepared in Example 1;
g (287 ml) was withdrawn, and 498 g (732 ml) of heptane was added dropwise over 15 minutes while stirring at room temperature. After completion of the addition, 121 g of a fraction containing methylene chloride as the main component at a temperature of 55 to 90 ° C. under normal pressure. Was distilled. At the end of the distillation, TBA-BP was a slurry solution partially containing a resinous material. The distillate was analyzed by gas chromatography.
g, and the recovery of methylene chloride was 39.9%.

After completion of the dropping, the obtained TBA-BP was filtered by suction, washed with water, and dried to obtain 182.1 g of pale yellow crystals partially containing resinous substances. This obtained TBA
As a result of analyzing the -BP crystal by liquid chromatography, the purity of TBA-BP was 97.0%,
The recovery of BA-BP was 95.5%. The melting point of the crystal was measured and found to be 100-106 ° C.

[0034]

As is apparent from the above description, according to the method of the present invention, a high quality TBA-BP solution is obtained from the TBA-BP solution obtained in the production process by a simple reprecipitation method as compared with the conventional method. BP can be obtained as fine powder.

Further, since the TBA-BP in the filtrate can be efficiently recovered, the treatment of the TBA-BP is not required, the product cost can be reduced, and the TBA-BP can be industrially advantageously used.
This is an extremely useful technique for recovering sucrose.

Claims (1)

(57) [Claims] 1. Fine powder of bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] propane produced by a bromination reaction of bis (4-allyloxy-3,5-dibromophenyl) propane In the method of separating and recovering, a solution of bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] propane dissolved in a good solvent obtained in the production process has a boiling point higher than that of the good solvent. Is added, and after completion of the addition, bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] propane is recovered as a fine powder in which the poor solvent is dispersed while the good solvent is distilled off. [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl]
A method for separating and recovering propane.