JPH05294871A - Production of bisphenol a - Google Patents

Abstract

PURPOSE:To efficiently produce a bisphenol A which is high in purity, free from the coloration, etc., and excellent in the hue. CONSTITUTION:A method for producing the bisphenol A comprises the steps of reacting acetone with phenol in the presence of an acidic catalyst, separating the obtained bisphenol A as its adduct with the phenol, dissolving the adduct in water as a solvent, cooling the solution to deposit the crystals of the bisphenol A, and then recrystallizing the crystals from an aromatic hydrocarbon solvent.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing bisphenol A.

[0002]

BACKGROUND OF THE INVENTION Bisphenol A has a chemical name of 2,2-
Bis (4-hydroxyphenyl) propane, which can be obtained by reacting acetone with an excess of phenol in the presence of an acidic catalyst such as hydrochloric acid or a strongly acidic cation exchange resin. In this method, the reaction mixture is first separated by-produced water or acid, and then cooled to be precipitated as an adduct of bisphenol A and phenol. If necessary, this adduct is purified by recrystallization once or twice or more, and then dephenoled to give bisphenol A.
It is said that. As a dephenol method for recovering bisphenol A from an adduct, a distillation or evaporation method is generally used. However, since this method exposes bisphenol A to a high temperature, bisphenol A to be a product is obtained. -There is a risk of heat deterioration (mainly coloring) of le A. Several methods have been proposed that do not require such distillation or evaporation.
For example, in Japanese Examined Patent Publication No. 63-40775, adduct is mixed with water to be melted, and this is cooled to obtain a bisphenol-containing compound.
A method for separating crystals of le A is described. In addition, Japanese Patent Publication No. 41-4978 discloses a method in which water is added to a reaction mixture and then cooled to separate bisphenol A. However, it is difficult to obtain bisphenol A suitable for applications requiring high purity by these methods.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing bisphenol A having a high purity and an excellent hue without coloring.

[0004]

The present inventors separated bisphenol A obtained by reacting acetone and phenol in the presence of an acidic catalyst as an adduct with phenol, and then separated water from the bisphenol A. This adduct is dissolved as a solvent and then cooled to precipitate crystals of bisphenol A,
This is a method for producing bisphenol A, which comprises recrystallizing this crystal using an aromatic hydrocarbon solvent.

The reaction of acetone and phenol in the presence of an acidic catalyst can be carried out by any method, but a method using a strongly acidic cation exchange resin as a catalyst is advantageous. After separating water or acid from this reaction mixture as necessary,
When this is cooled, bisphenol A and an adduct of phenol are deposited. This adduct is a pheno
It may or may not be purified by recrystallizing the solvent as a solvent, but by carrying out this purification, bisphenol A having a higher purity can be obtained.

In this way, the present invention separates the phenol from the separated adduct without carrying out a treatment such as evaporation or distillation which may cause thermal deterioration, thereby producing a high-purity bisphenol A. Is what you get. First, the adduct is dissolved in water. The amount of water is in the range of 1 to 20 times, preferably 5 to 10 times the amount of adduct. As the amount of water increases, the concentration of phenol in the obtained bisphenol A decreases, but the loss of bisphenol A increases, so the above range is preferable. In addition, the method of precipitating crystals after dissolving the adduct in a solvent other than water causes a decrease in the yield of bisphenol A and a high concentration of phenol in bisphenol A. After melting, the temperature for precipitating crystals is 30 to 80 ° C, preferably 45 to 60 ° C. If the temperature is too low, the concentration of phenol in bisphenol A will be high, and if it is high, the yield will decrease, so the above range is preferable. The precipitated crystal is bisphenol A having a relatively high purity, but if necessary, it can be recrystallized once or twice or more with water as a solvent, but the content of the phenol is several tens ppm or To reach the following concentrations requires quite a few times,
It is not practical to raise the purity only by this recrystallization.

Therefore, in the present invention, a crystal of bisphenol A precipitated by dissolving the adduct in water and cooling, or a crystal obtained by recrystallizing the crystal with water is prepared by using an aromatic hydrocarbon solvent. Recrystallize. As the aromatic hydrocarbon solvent, any solvent can be used as long as the solubility of bisphenol A is lowered by cooling, but is preferably relatively low such as benzene, toluene, xylene and ethylbenzene. It is a solvent having a boiling point, and most preferably toluene. In addition, the solvent is n- other than aromatic hydrocarbons.
With hexane, cyclohexane, etc., the purification effect is low. Further, even with a mixed solvent of water and aromatic hydrocarbon, the purification effect is low as compared with the case of using each solvent separately. The amount of the aromatic hydrocarbon solvent used is bisphenol-
The range of 1 to 30 times by weight, preferably 3 to 15 times by weight, of the amount of A is good. After melting, the temperature for precipitating crystals is 20 to 60 ° C., preferably 30 to 50 ° C. If the temperature is too low, the phenol in Bisphenol A
If the concentration is high, the yield will decrease if the concentration is high, so the above range is preferable. If this recrystallization is performed twice or more,
Although the purity is further improved, the yield is lowered, so it is preferable to limit the number to twice or less. Crystals precipitated by recrystallization are subjected to solid-liquid separation by filtration or the like, washed if necessary, and then dried under reduced pressure to obtain bisphenol A as a product.

[0008]

【Example】

Example 1 A low boiling point substance such as water was separated from a reaction mixture obtained by reacting acetone and phenol with a strongly acidic cation exchange resin as a catalyst, and this was cooled to cool the bisphenol A.
And a phenol adduct was deposited. The precipitated adduct was separated and recrystallized using phenol as a solvent to separate purified adduct crystals. 100 g of this crystal (bisphenol A content about 70% by weight)
Is put in 1000 g of water and stirred at 90 to 95 ° C.
The mixture was heated to completely dissolve the crystals. Then 5 ° C / h
The mixture was cooled to 50 ° C. at a rate of r to precipitate crystals of bisphenol A, and filtered while maintaining this temperature. filtration,
The separated crystals were put in 500 g of toluene and heated to 90 ° C. with stirring. After completely dissolving, 5 ℃ /
The mixture was cooled to 50 ° C. at a rate of hr to precipitate crystals of bisphenol A, and filtered while maintaining this temperature. The crystals were dried for 1 hr under conditions of 100 ° C. and 10 mmHg to remove the solvent. The recovered crystal was 56 g, and the recovery rate was 80 mol% based on the adduct used.
The concentration of phenol in this crystal was 10 ppm as a result of liquid chromatography analysis.

Example 2 The same operation as in Example 1 was carried out except that the amount of toluene was 250 g. 58 g of crystals were recovered,
The recovery rate was 83 mol% based on the adduct used. The concentration of phenol in this crystal was 10 ppm.

Comparative Example 1 The same operation as in Example 1 was performed except that the operation of using toluene as a recrystallization solvent was omitted. 6 crystals recovered
It was 5 g, and the recovery rate was 93 mol% based on the adduct used. However, the concentration of phenol in this crystal was 360 ppm.

Comparative Example 2 The same operation as in Example 1 was carried out except that the crystal of the adduct was dissolved in water and the crystal precipitation operation was omitted, and the crystal was directly dissolved in toluene. The recovered crystals were 50 g, and the recovery rate was 71 mol% based on the adduct used. However, the concentration of phenol in this crystal was 550
It was ppm.

Comparative Example 3 The same procedure as in Example 1 was performed except that the adduct crystals were first dissolved in toluene, the crystals were precipitated, and then the crystals were dissolved in water, and the order was changed to precipitate the crystals. went. The recovered crystal was 51 g, and the recovery rate was 73 mol% based on the adduct used. However, the concentration of phenol in this crystal was 320 ppm.

[0013]

According to the production method of the present invention, it is possible to efficiently produce bisphenol A having a high purity and an excellent hue without coloring.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Kaho, 4-10-3 Nakai, Kokurakita-ku, Kitakyushu, Fukuoka (72) Inventor, Masashi Furumoto 2-13-3, Nakai, Kitakyushu, Kitakyushu, Fukuoka

Claims (2)

[Claims] 1. A bisphenol A obtained by reacting acetone with phenol in the presence of an acidic catalyst is separated as an adduct with phenol, and then the adduct is dissolved with water as a solvent, and then the adduct is dissolved. Cool this and bispheno
Of bisphenol A, which is characterized by precipitating crystals of A and then recrystallizing the crystals using an aromatic hydrocarbon solvent.
Manufacturing method. 2. The method for producing bisphenol A according to claim 1, wherein the aromatic hydrocarbon solvent is benzene, toluene, xylene or ethylbenzene.