JPH07107043B2 - Method for purifying bisphenol sulfones - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for purifying bisphenol sulfones. More specifically, the present invention relates to a method for removing the color of crude bisphenol sulfones obtained by the reaction of resorcinol or nuclear alkylated phenols with sulfuric acid.

[Conventional technology]

Bisphenol sulfones have recently been used for polycarbonate,
It is used as a raw material for engineering plastics such as polyester and as a developer for thermal recording paper.

Crude bisphenol sulfones obtained by dehydration of phenols and sulfuric acid are usually strongly colored. In the above-mentioned applications, the coloring is required to be extremely small, and therefore it is necessary to remove the coloring of the crude bisphenol sulfone and to purify it.

In order to obtain less colored bisphenol sulfones,
Conventionally, various methods have been proposed. For example, Japanese Patent Publication No. 38-5274 discloses a method of treating with decolorizing carbon, but the solution is still colored light pink.
Japanese Patent Publication No. 55-37550 discloses a method of dissolving the reaction product in an aqueous phenol solution and separating the solution into two layers to separate and remove the lower layer containing oily impurities that cause coloring. However, there is a problem that the upper layer containing the purified product is inevitably mixed with phenol, which causes new coloring.

JP-A-58-500615 discloses that after dissolving crude bisphenol sulfones in water-soluble ammonium hydroxide,
A method of obtaining a purified product by heating to vaporize ammonia to selectively precipitate sulfone and removing it from the upper layer solution is described. Hard to implement.

[Problems to be solved by the invention]

The inventors of the present invention did not have the drawbacks of these conventional techniques, can be industrially advantageously carried out, and as a result of various studies on a purification method for obtaining a colorless bisphenol sulfone, a crude colored bisphenol sulfone was obtained. The present inventors have found that coloring impurities can be easily removed by heat treatment in a specific polar medium, and have reached the present invention.

[Means for solving problems]

The present invention provides crude bisphenol sulfones obtained by dehydration reaction of resorcinol or nuclear alkylated phenols with sulfuric acid as organic compounds of aliphatic alcohols having 4 to 8 carbon atoms, glycols, phenols and alkylene glycol monoethers. 100 to 200 in one or more media selected from the group consisting of
Provided is a method for purifying bisphenol sulfones, which comprises heat treatment at a temperature of ℃.

The crude bisphenol sulfones used in the present invention are obtained by the dehydration reaction of resorcinol or nuclear alkylated phenols with sulfuric acid. Here, the nuclear alkylated phenol is, for example, orthocresol,
Metacresol, para-cresol, 2,4-xylenol, 2,6-xylenol, orthoethylphenol and the like are shown. Further, as the organic compound having a hydroxyl group used for purification, aliphatic alcohols having 4 to 8 carbon atoms such as n-butanol and 2-ethylhexanol,
Use glycols such as ethylene glycol, propylene glycol, diethylene glycol, dipropylene glycol and triethylene glycol, phenols such as phenol, cresol and xylenol, alkylene glycol monoethers such as methyl cellosolve, ethyl cellosolve and butyl cellosolve. be able to.

To purify the crude bisphenol sulfone, one kind of medium selected from the group consisting of these organic compounds and water may be used, or two or more kinds of medium may be mixed and used. Crude bisphenol sulfones containing colored impurities, obtained by dehydration reaction of resorcinol or nuclear alkylated phenols with sulfuric acid, were dispersed in a medium at room temperature and then 100 ° C to 200 ° C.
Heat treatment at the temperature of. If the processing temperature is less than 100 ° C, the decolorizing effect is small. When the treatment temperature is equal to or lower than the boiling point of the medium, the treatment can be performed at atmospheric pressure in a vessel equipped with a reflux condenser and equipped with a stirrer. When the treatment temperature is not lower than the boiling point of the medium, the heat treatment can be performed by using a high pressure vessel such as an autoclave. When the treatment temperature is higher than 200 ° C, the bisphenol sulfone is colored again by heat, which is not preferable. The amount of medium used is preferably 1 to 1 of crude bisphenol sulfone.
The amount is 10 times, more preferably 2 to 5 times. The crude bisphenol sulfone may be completely dissolved in the medium at the processing temperature, or may not be completely dissolved and may remain in a dispersed state. Even when the crude bisphenol sulfones are not completely dissolved in the medium, the heat treatment causes the colored components to migrate into the medium,
The purpose of purification can be achieved. Heat treatment for 10 minutes to 5
It is preferable to spend time. Next, the mixture containing the bisphenol sulfone and the medium, which has been subjected to the heat treatment, is cooled to room temperature, and the bisphenol sulfone is separated by using an appropriate apparatus. At this time, it is desirable to wash away the medium in which the coloring component adhering to the bisphenol sulfone to be purified is dissolved by using an appropriate solvent after the completion. Usually, it is convenient to use a solvent having a relatively low boiling point by uniformly mixing with the medium used for the heat treatment. After overwashing, the purified bisphenol sulfone is dried.

〔Example〕

 Hereinafter, the present invention will be further described with reference to examples.

In addition, the light absorbency in an Example is a value measured by the following method.

25% aqueous ammonia solution of bisphenol sulfone (28
% Ammonia water, special grade reagent used), and optical path length 10 mm
Absorbance at 480 nm was measured with a cell of No. 2 using a digital double beam spectrophotometer UV-150-02 manufactured by Shimadzu Corporation.

Example 1 2500 g of 2,6-xylenol and 750 g of 98% sulfuric acid were charged into a 5 l reactor made of stainless steel, and the produced water was distilled off.
The reaction was carried out at ~ 180 ° C for 4 hours. Remove the reaction mixture,
After cooling, bis (3,5-dimethyl-4-hydroxyphenyl) sulfone was obtained as a purple-red powder. The absorbance of this product was 0.219.

In a 500 ml flask, add the crude bis (3,5
-Dimethyl-4-hydroxyphenyl) sulfone 100 g and
Add 300 g of 2,6-xylenol, stir at 140-160 ° C for 15 minutes, then cool, separate the crystals of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone, and wash the crystals with 100 g of methanol. After that, it was dried to obtain 85 g of purified bis (3,5-dimethyl-4-hydroxyphenyl) sulfone (white powder). The absorbance of this product was 0.031.

Example 2 100 g of crude bis (3,5-dimethyl-4-hydroxyphenyl) sulfone synthesized in the same manner as in Example 1 and 200 g of ethylene glycol were added to a 500 ml flask, and 170-180
After stirring for 4 hours at 0 ° C., cooling, separating the crystals in the same manner as in Example 1, washing and drying, 80 g of bis (3,5-
Dimethyl-4-hydroxyphenyl) sulfone was obtained (white powder). The absorbance of this product was 0.030.

Comparative Example 1 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized in the same manner as in Example 1 in a 500 ml flask.
Add 80g of sulfone and 200g of ethylene glycol,
After stirring at 15 ° C for 15 minutes, cooling, separating the crystals in the same manner as in Example 1, washing and drying, 92 g of bis (3,5-
Dimethyl-4-hydroxyphenyl) sulfone was obtained (purple red powder). The absorbance of this product was 0.117.

Example 3 In a 500 ml flask, 100 g of crude bis (3,5-dimethyl-4-hydroxyphenyl) sulfone synthesized in the same manner as in Example 1 and 350 g of butyl cellosolve were added, and the temperature was 150 to 165 ° C.
After stirring for 1 hour, separate by the same method as in Example 1,
After washing and drying, 88 g of bis (3,5-dimethyl-4
-Hydroxyphenyl) sulfone was obtained (white powder).
The absorbance of this product was 0.027.

Example 4 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized as in Example 1 in a 500 ml flask.
Add 100 g of sulfone and 250 g of 2-ethylhexanol,
After stirring at 0 to 190 ° C. for 30 minutes, the mixture was separated by the same method as in Example 1, washed and dried to obtain 90 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone (white. Powder). The absorbance of this product was 0.035.

Example 5 To a 1000 ml glass autoclave were added 100 g of crude bis (3,5-dimethyl-4-hydroxyphenyl) sulfone synthesized in the same manner as in Example 1 and 400 g of water, and the mixture was stirred at 140 to 160 ° C. for 2 hours. After cooling, the crystals were separated, washed with 100 g of water, and dried to obtain 95 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone (white powder). The absorbance of this product was 0.060.

Example 6 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized in the same manner as in Example 1 in a 500 ml flask.
100 g of sulfone, 200 g of ethylene glycol and 16 g of water were added as a mixed solvent, and the mixture was stirred at 130 to 145 ° C. for 20 minutes,
The mixture was cooled, passed through the same method as in Example 1, washed and dried to obtain 83 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone (white powder). The absorbance of this product was 0.018.

Comparative Example 2 100 g of crude bis (3,5-dimethyl-4-hydroxyphenyl) sulfone synthesized in the same manner as in Example 1 and 200 g of xylene were added to a 500 ml flask, and the mixture was stirred at 140 to 143 ° C. for 60 minutes and then cooled. Then, the mixture was separated by the same method as in Example 1, washed and dried to obtain 98 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone (purple red powder). The absorbance of this product was 0.195.

Comparative Example 3 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized in the same manner as in Example 1 in a 500 ml flask.
100 g of sulfone and 200 g of kerosene were added, and the mixture was stirred at 140 to 150 ° C. for 60 minutes, cooled, separated in the same manner as in Example 1, washed and dried to give 98 g of bis (3,5-dimethyl- 4-Hydroxyphenyl) sulfone was obtained (purple red powder). The absorbance of this product was 0.182.

Example 7 2160 g of autocresol and 830 g of 98% sulfuric acid were charged into a 5 l reactor made of stainless steel, and the produced water was distilled off.
The reaction was carried out at ~ 180 ° C for 4 hours. Remove the reaction mixture,
After cooling, red-brown lumps of bis (3-methyl-4-hydroxyphenyl) sulfone were obtained. The absorbance of this product is 1.
It was 22.

In a 500 ml flask, the crude bis (3
-Methyl-4-hydroxyphenyl) sulfone 100 g and 2
-Ethylhexanol (300 g) was added, and the mixture was stirred at 130 to 140 ° C for 1 hour, cooled, separated from the crystal, washed with 100 g of methanol, and dried to obtain 83 g of bis (3-methyl-4).
-Hydroxyphenyl) sulfone was obtained (white powder).
The absorbance of this product was 0.057.

Comparative Example 4 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized in the same manner as in Example 1 in a 500 ml flask.
100 g of sulfone, 700 g of methanol, and 200 g of water were added, and the mixture was stirred under reflux (60 to 70 ° C.) for 1 hour, cooled, and crystals were separated by filtration, washed and dried in the same manner as in Example 1. 74 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone were obtained (purple red powder). The absorbance of this product is 0.153
Met.

Comparative Example 5 Crude bis (3,5-dimethyl-4-hydroxyphenyl) synthesized in the same manner as in Example 1 in a 500 ml flask.
100 g of sulfone, 700 g of isopropyl alcohol, and 200 g of water were added, and the mixture was stirred under reflux (75 to 85 ° C.) for 1 hour, cooled, and crystals were separated by filtration, washed and dried in the same manner as in Example 1. , 62 g of bis (3,5-dimethyl-4-hydroxyphenyl) sulfone was obtained (purple red powder). The absorbance of this product was 0.132.

〔The invention's effect〕

As is apparent from the above data, in accordance with the present invention, the crude bisphenol sulfones were selected from the group consisting of C4-8 aliphatic alcohols, glycols, phenols and organic compounds of alkylene glycol monoethers and water. 10 or more in one or more media
Bisphenol that can be easily decolorized and refined by heating to 0 to 200 ° C, and can withstand use even in fields requiring extremely little coloring, such as engineering plastics such as polycarbonate and color developer for thermal recording paper. Sulfones can be provided.

Claims (1)

[Claims] 1. A crude bisphenol sulfone obtained by a dehydration reaction of resorcinol or a nuclear alkylated phenol with sulfuric acid is used as an organic solvent of an aliphatic alcohol having 4 to 8 carbon atoms, glycols, phenols and alkylene glycol monoethers. 100-200 in one or more media selected from the group consisting of compounds and water
A method for purifying bisphenol sulfones, which comprises heat treatment at ℃.