JP2853244B2 - Preparation of bis [3,5-dibromo-4- (dibromopropoxy) phenyl] sulfone - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Application Field] The present invention relates to bis [3,5-dibromo-4- (2,3-dibromopropoxy) phenyl] sulfone (hereinafter abbreviated as TBS-BP). The present invention relates to a production method for obtaining industrially high yield and high purity.

TBS-BP is useful as a flame retardant for polyolefin resins and the like, and is particularly useful as a flame retardant for polypropylene and the like.
-23693.

[Conventional technology]

Conventionally, bis (4-hydroxy-3,5-dibromophenyl) sulfone (hereinafter abbreviated as TBS) has been used as a raw material for TBS-BP.
First, TBS is prepared in the presence of an alkali using bis (4-allyloxy-3,5-dibromophenyl) sulfone (hereinafter abbreviated as TBS-BA) using allyl bromide or allyl chloride as an allylating agent. A method of producing TBS-BP by reacting and precipitating the crystals of the above (1), (2), filtering the crystals, drying the crystals, and then reacting the crystals with bromine (Japanese Patent Publication Nos. 50-35103 and 50-35103). 50-2
3693, JP-B-63-39585).

However, this method requires a filtration separation and washing step of the TBS-BA crystals precipitated by the allylation reaction,
Further, the obtained crystals had to be transferred to the next bromination step after drying, so that the production process on an industrial scale was very complicated. In addition, a small amount of the unreacted allylating agent remains during filtration and exhibits a strong odor, which has a problem in the working environment.

[Problems to be solved by the invention]

An object of the present invention is to provide an industrial method for producing TBS-BP with high yield and high purity by simplifying complicated unit operations in the prior art.

[Means for solving the problem]

In view of the above situation, the present inventors have made intensive studies to rationalize the manufacturing process. As a result, TBS-BP
In the method for producing, after completion of the allylation reaction of TBS,
When TBS-BA is extracted using a halogenated hydrocarbon solvent, not only can TBS-BA be extracted selectively, but also it can be further subjected to the next bromination step in the state of the extracted solution. The obtained TBS-BP has high purity and high yield, and it has been found that the working environment for production can be greatly improved, and the present invention has been completed.

That is, the gist of the present invention is that a halogenated hydrocarbon solvent is added to an aqueous solution of an alkaline slurry of TBS-BA obtained by an allylation reaction of TBS, and TBS-BA is selectively extracted into an organic phase and separated. Thereafter, there is provided a method for producing TBS-BP, wherein bromine is added to the organic phase to cause a reaction.

 The details will be described below.

[Action]

The reaction of allylating TBS using allyl bromide or allyl chloride as an allylating agent in the presence of an alkali can be explained using the following reaction formula.

The amount of the allylating agent used in the method of the present invention is TB
2 mol or more with respect to S1 mol, preferably 2.0 to 3.0 mol
Is a mole. No improvement in yield is observed even when 3.0 mol or more is added. The method for adding the allylating agent is not particularly limited. However, when allyl bromide is used, it is preferable to add the allylating agent dropwise at a rate of 1.5 mol / hour or less per 1 mol of TBS, since it is unstable to alkali. When the unreacted allylating agent remains after the reaction, it is preferable to remove the unreacted allylating agent by distillation from the viewpoint of high purification of TBS-BP.

As a reaction solvent used in the allylation reaction, a homogeneous aqueous solution in which water alone or a water-soluble organic solvent is mixed is used. In particular, when allyl chloride is used as the allylating agent, it is preferable from the viewpoint of reactivity to use a homogeneous aqueous solution mixed at a concentration of 25 to 60% by volume of a water-soluble organic solvent.

The water-soluble organic solvents are monohydric lower alcohols having 1 to 3 carbon atoms and ethers having 2 to 5 carbon atoms, and specifically, for example, methanol, ethanol, n-propanol, isopropanol, dioxane , THF, methyl cellosolve, ethyl cellosolve and the like. Among these, a water-isopropanol mixed solvent system is particularly preferred due to its high reactivity and the like.

The substrate concentration of TBS in the reaction solvent is not particularly limited, but is usually about 15 to 35% by weight.

When an organic solvent is mixed, it is necessary to remove the organic solvent by distillation after the completion of the reaction. TBS-BA without distillation
Is not preferable because the alkali metal salt of TBS-MA is also extracted.

In addition, when the concentration of the slurry increases during the distillation of the organic solvent, water is added as necessary.

Examples of the alkali used in the allylation reaction include hydroxides, carbonates and bicarbonates of alkali metals, such as sodium hydroxide, potassium hydroxide, sodium carbonate, and the like.
Potassium carbonate, sodium hydrogen carbonate, potassium hydrogen carbonate and the like can be mentioned.

The amount of the alkali used is 2 mol or more, preferably 2.0 to 3.0 mol, per 1 mol of TBS. Even if 3.0 mol or more is added, no particular improvement in the yield is observed.

Incidentally, the reaction solution after the reaction is required to be kept in an alkaline state in performing the subsequent extraction step, and particularly pH 10 to 14
It is preferable to keep in the range.

The reaction is usually performed at room temperature to 150 ° C. under normal pressure or under pressure. In the reaction under normal pressure, it is desirable to carry out the reaction at the reflux temperature of the reaction solution in order to increase the reaction rate. The reaction time depends on the reaction temperature and cannot be unconditionally determined, but is usually from 1 hour to 30 hours.

Next, the obtained TBS-BA is extracted using a halogenated hydrocarbon solvent.

The reason why only TBS-BA can be selectively extracted into the halogenated hydrocarbon solvent by the method of the present invention is considered as follows. The aqueous solution before the extraction mainly contains TBS-BA as a target substance and 4-allyloxy-4'-hydroxy- as a reaction intermediate.
Alkali metal salts, alkali metal chlorides and the like of 3,3 ', 5,5'-tetrabromodiphenyl sulfone (hereinafter abbreviated as TBS-MA) are present. Under alkaline conditions, hydrophobic TBS-BA is used. Other than that, all are hydrophilic or nearly hydrophilic, and it is considered that TBS-BA can be selectively extracted.

Further, the halogenated hydrocarbon which is the extraction solvent is a solvent inert to bromine, and the bromination of TBS-BA proceeds smoothly.

Examples of the halogenated hydrocarbon solvent to be used include methylene chloride, chloroform, carbon tetrachloride, dichloroethane, trichloroethane, tetrachloroethane, etc., which are usually used industrially. Among them, methylene chloride is particularly preferable because of problems such as solubility of TBS-BA and toxicity of a solvent.

The amount of this solvent used is determined experimentally in consideration of the partition coefficient depending on the type of solvent, extraction conditions, etc.
The necessary amount is added so that the substrate concentration of BA is usually about 5 to 25% by weight. The extraction is carried out once or several times.

The temperature at which the extraction is performed is not particularly limited, but is not higher than the boiling point of the solvent used, usually about 10 to 80 ° C.

Next, bromine was added to the extraction solution containing TBS-BA to add TBS-BA.
The reaction for producing BP can be described using the following reaction formula.

The amount of bromine used in the TBS-BP reaction is T
2 mol or more, preferably 2.1 mol per mol of BS-BA
It is about 2.5 mol. No improvement in yield and purity is observed even when 2.5 mol or more is added.

The method of adding bromine is performed by dropping, and the dropping speed is
It is 5 mol / hour or less per 1 mol of TBS-BA, preferably about 1 to 3 mol / hour. Bromine dripping speed
When the amount is 5 mol / hour or more per 1 mol of TBS-BA, the heat generation during the reaction is undesirably increased.

The reaction temperature is equal to or lower than the boiling point of bromine, and preferably about 5 to 50 ° C.

When the reaction temperature is lower than 5 ° C., the reaction becomes extremely slow, which is not preferable.

After the completion of the dropping, it is necessary to further ripen at the dropping temperature for at least one hour in order to complete the reaction.

The reaction solution containing TBS-BP obtained in the method of the present invention is a method for removing unreacted residual bromine, usually a reducing agent used industrially, for example, sodium hydrogen sulfite, sodium thiosulfate, sodium formate, After treatment with hydrazine or the like, the product is washed with water and the solvent is removed to obtain a product. can get
The TBS-BP crystals are of high purity and can be used as such as a flame retardant such as a polyolefin resin.

〔The invention's effect〕

When TBS-BP is produced using TBS as a raw material, in the conventional production method, as described above, since the intermediate raw material TBS-BA is precipitated as crystals, it is necessary to perform steps such as filtration and separation of the crystals. Therefore, from the industrial point of view, the method is very complicated.

However, as is clear from the above description, according to the present invention, only TBS-BA is selectively extracted with a solvent, and TBS-BA is brominated in the solvent. In addition, the next bromination step can be performed without the need for a washing step and a drying step, and a simplified manufacturing process can be achieved. In addition, the problem of odor of the unreacted allylating agent at the time of TBS-BA filtration is eliminated, so that the working environment is improved.
That is, in the method of the present invention, it is possible to simplify the production process such as filtration and separation, washing steps, and the like, and to improve the working environment.In addition, high-quality and high-yield TBS-BP can be industrially produced. In addition, it has become possible to produce it in an advantageous manner.

〔Example〕

Hereinafter, the present invention will be described in more detail with reference to Examples, but the present invention is not limited thereto.

Example 1 A 1000 ml four-necked flask having a thermometer, a stirring blade and a cooling tube was charged with 256 ml of isopropanol, 180 ml of water and Na
16.8 g (420 mmol) of OH was charged, and 113.2 g of TBS (200 mmo)
l) was added and dissolved.

Next, the temperature was raised to 70 ° C. while maintaining the temperature, 60.5 g (500 mmol) of allyl bromide was added dropwise over 5 hours. After completion of the dropping of the allyl bromide, the temperature was raised to 70 to 80 ° C., and the reaction was carried out at that temperature for 3 hours.

After completion of the reaction, isopropanol and unreacted allyl bromide in the obtained slurry solution were distilled off at an azeotropic temperature with water while dropping 200 g of water. After the removal by distillation, the pH of the reaction solution was measured and found to be pH 10.7.

Next, 650 g of methylene chloride was added to the obtained slurry solution at room temperature, and the mixture was stirred and separated for 10 minutes to obtain a solution of the organic phase solution 74.
9 g were obtained. The components contained in this solution were analyzed by liquid chromatography, and as a result, TBS-BA11
Only 9.0g was included. The yield of TBS-BA corresponds to 92.1%. In addition, Na salt of TBS-MA which was a reaction intermediate was not detected.

Further, the aqueous phase was analyzed by liquid chromatography, and as a result, the reaction intermediate TBS-MA Na salt 6.5
g, 2.1 g of unextracted TBS-BA remained. In addition,
TBS does not remain in both the organic and aqueous phases, and the TBS conversion rate is
The total yield of 100% and TBS-BA was 93.7%.

Next, the obtained organic phase was charged into a four-necked flask having a capacity of 1000 ml having a thermometer, a stirring blade, and a cooling tube, and the bromine was stirred for 67.7 minutes.
g (423 mmol) was added dropwise at 39 ° C. over 1 hour.
Aging took place at that temperature for hours.

After the reaction, the residual bromine was reduced with an aqueous solution of sodium hydrogen sulfite, and after washing with water, the solvent was removed to obtain 173.6 g of TBS-BP crystals.

The obtained crystals were analyzed by liquid chromatography. As a result, the TBS-BA conversion was 100%,
The BP purity was 97.3%, and the yield of TBS-BP was 95.0% (based on TBS-BA). The yield of TBS-BP from TBS was 87.5%.
Met.

 Tables 1 and 2 show the reaction conditions and results in each step.

(Example 2) In a four-necked flask having a capacity of 1000 ml having a thermometer, a stirring blade and a cooling tube, 174 ml of isopropanol, 260 ml of water and Na
16.8 g (420 mmol) of OH was charged, and 113.2 g of TBS (200 mmo)
l) was added and dissolved.

Next, 38.3 g (500 mmol) of allyl chloride was added all at once, and the mixture was heated to the reflux temperature and heated for 15 hours.

In addition, 3.2 g (80 mmol) of NaOH was added 8 hours after the start of the reaction.

After the completion of the reaction, isopropanol and unreacted allyl chloride in the obtained slurry solution were distilled off at an azeotropic temperature with water while dropping 200 g of water. After the removal by distillation, the pH of the reaction solution was measured to be 11.8.

Next, 480 g of methylene chloride was added to the obtained slurry solution at room temperature, and the mixture was stirred for 10 minutes to separate the organic phase solution.
539 g were obtained. The components contained in this solution were analyzed by liquid chromatography, and as a result, TBS-BA9
Only 8.8g was included. The yield of TBS-BA corresponds to 76.5%. In addition, Na salt of TBS-MA which was a reaction intermediate was not detected.

Further, the aqueous phase was analyzed by liquid chromatography.As a result, the reaction intermediate TBS-MA Na salt 16.
0 g and unextracted TBS-BA 6.6 g remained. Further, TBS as a raw material did not remain in both the organic phase and the aqueous phase, the TBS conversion was 100%, and the total yield of TBS-BA was 81.6%.

Next, the obtained organic phase was charged into a four-necked flask having a capacity of 1000 ml having a thermometer, a stirring blade, and a cooling tube.
g (321 mmol) was added dropwise at 40 ° C. over 1 hour.
Aging took place at that temperature for hours.

After the reaction, residual bromine was reduced with an aqueous solution of sodium hydrogen sulfite, and further washed with water. Then, the solvent was removed to obtain 147.5 g of white crystals.

The obtained crystals were analyzed by liquid chromatography. As a result, the TBS-BA conversion was 100%,
-BP purity was 97.0%, and the yield of TBS-BP was 96.9% (based on TBS-BA). The yield of TBS-BP from TBS was 74.1%.
Met.

 Tables 1 and 2 show the reaction conditions and results in each step.

(Examples 3 to 5) According to Example 1, raw materials having the compositions shown in Tables 1 and 2 were charged and reacted under the reaction conditions shown in Tables 1 and 2. The same post-treatment as in Example 1 was performed to obtain TBS-BP. Table showing the results obtained
Shown in 1 and 2.

(Comparative Example 1) In a four-neck flask with a capacity of 1000 ml having a thermometer, a stirring blade and a cooling tube, 174 ml of isopropanol, 260 ml of water, and NaOH
16.8 g (420 mmol) was charged, and further TBS 113.2 g (200 mmol)
Was added and dissolved.

Next, 38.3 g (500 mmol) of allyl chloride was added all at once, and the mixture was heated to the reflux temperature and heated for 15 hours.

In addition, 3.2 g (80 mmol) of NaOH was added 8 hours after the start of the reaction.

After the completion of the reaction, the obtained slurry solution was filtered and further washed with water to obtain 163.3 g of wet crystals of TBS-BA. During the filtration, the odor of unreacted allyl chloride was trapped.

Next, the obtained wet crystals were dried under reduced pressure at 90 ° C. for 8 hours to obtain 98.0 g of dry crystals of TBS-BA. This obtained TBS
Analysis of the dry crystals of BA and the above filtrate by liquid chromatography showed that the conversion of TBS was 100
%, The dry crystal yield of TBS-BA was 75.9%, and the dry crystal purity of TBS-BA was 100%. The filtrate contains a reaction intermediate T
Only the Na salt of BS-MA is dissolved, and the target substance, TBS-B
A was hardly dissolved.

Next, a capacity of 1000 ml with thermometer, stirring blade and cooling pipe
Was charged with the dried crystals of TBS-BA, and 500 g of methylene chloride was added to dissolve the crystals, and 55.8 g of bromine (349 mm
ol) was added dropwise at 40 ° C. over 1 hour, and after the addition, aging was performed at that temperature for 2 hours.

After the reaction, the residual bromine was reduced with an aqueous solution of sodium hydrogen sulfite, washed with water, and the solvent was removed to obtain 142.3 g of white crystals.

The obtained crystals were analyzed by liquid chromatography. As a result, the TBS-BA conversion was 100%,
-BP purity was 97.3%, and TBS-BP yield was 94.5% (based on TBS-BA). The yield of TBS-BP from TBS was 71.7%.
Met.

(Comparative Example 2) In a four-necked flask having a capacity of 1000 ml having a thermometer, a stirring blade and a cooling tube, 174 ml of isopropanol, 260 ml of water, and NaOH
16.8 g (420 mmol) was charged, and further TBS 113.2 g (200 mmol)
Was added and dissolved.

Next, 38.3 g (500 mmol) of allyl chloride was added all at once, and the mixture was heated to the reflux temperature and heated for 15 hours.

In addition, 3.2 g (80 mmol) of NaOH was added 8 hours after the start of the reaction. After the reaction was completed, the pH of the reaction solution was measured.
11.0.

Next, 480 g of methylene chloride was added to the obtained slurry solution at room temperature, and the mixture was stirred and separated for 10 minutes to obtain a solution of the organic phase.
730.5 g was obtained. The components in this solution were analyzed by liquid chromatography, and as a result, TBS-BA was 96.9.
g, 23.1 g of Na salt of TBS-MA, a reaction intermediate, almost all of isopropanol charged at the beginning of the reaction, and 2.1 g of unreacted allyl chloride. Incidentally, the yield of TBS-BA was 75.0%.

Further, the aqueous phase was analyzed by liquid chromatography, and as a result, Na salt of TBS-MA as a reaction intermediate was 0.3
g and 0.1 g of unextracted TBS-BA were dissolved. In addition,
TBS does not remain in both the organic and aqueous phases, and the TBS conversion rate is
100%.

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) C07C 317/22 C07C 315/04

Claims (1)

(57) [Claims] A bis (4-hydroxy-3,5-dibromophenyl) sulfone obtained by an allylation reaction of bis (4-hydroxy-3,5-dibromophenyl) sulfone.
A halogenated hydrocarbon solvent is added to an aqueous alkaline slurry solution of allyloxy-3,5-dibromophenyl) sulfone, and bis (4-allyloxy-3,5-dibromophenyl) sulfone is selectively extracted into an organic phase. After doing
Bis [3,5-dibromo-4- (2,3-dibromopropoxy), characterized in that bromine is added to the organic phase and reacted.
Phenyl] sulfone.