JPH0539239A - Production of bisphenol a having excellent hue - Google Patents

Abstract

PURPOSE:To provide a method for producing highly pure bisphenol A having an excellent hue. CONSTITUTION:In a method for obtaining bisphenol A by washing the crystalline adduct of the bisphenol A and phenol with phenol, the method for producing the bisphenol A having an excellent hue is characterized by employing, as the washing phenol, a pure phenol obtained by bringing industrial phenol into contact with a strong acid type ion exchange resin and subsequently distilling the treated phenol.

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 having high purity and excellent hue. Bisphenol A is a raw material for polycarbonate resins and epoxy resins, and in recent years, the demand for bisphenol A that is colorless and transparent and has high purity, which is particularly suitable for optical applications, has significantly increased.

[0002]

2. Description of the Related Art Bisphenol A [2,2]
It is known to react excess phenol with acetone in the presence of an acid catalyst to produce [bis (4-hydroxyphenyl) propane]. Further, in order to separate and recover high-purity bisphenol A from this reaction product, the reaction product was cooled to crystallize a crystal adduct of bisphenol A and phenol (hereinafter, also simply referred to as a crystal adduct). It is also known to remove phenol from adduct crystals. In such a method for producing bisphenol A, the purity of bisphenol A recovered as a product obviously depends largely on the removal rate of phenol from the crystal adduct,
It is also affected by impurities other than phenol contained in adduct crystals. A method of washing adduct crystals with liquid phenol in order to remove impurities other than phenol contained in crystal adducts is known (JP-A-1-
146839). This known method is characterized in that the phenol separated from the crystal adduct is used as the liquid phenol for washing, whereby a product bisphenol A having a hue better than that of the industrial phenol is obtained. In this case, the phenol is separated from the crystal adduct by evaporation, extraction, stripping with steam or the like. As a method for removing phenol from the crystal adduct by evaporation, specifically, Japanese Patent Publication No. 52-4
No. 2790, the crystalline adduct is vaporized at a temperature above 180 ° C. and under reduced pressure for 0.1 to 30 minutes, and phenol is fractionally condensed to give bisphenol A.
Can be mentioned. However, such a method has the following problems and is not yet satisfactory. (1) In the phenol separated by evaporation or steam stripping, impurities such as chroman and 2,4'-bisphenol A contained in the adduct itself and the cause of coloring such as isopropenylphenol generated by heating in the separation step. Impurities to be mixed in. This is especially noticeable when the evaporation temperature is high. If phenol containing these impurities is used for adduct cleaning, a product of high purity and good hue, bisphenol A, cannot be obtained. (2) When the solvent extraction method is used, equipment and utilities for separating the solvent and the phenol are required, and the phenol separated by the solvent extraction contains a mixture of the solvent, and the solvent is mixed with the phenol after washing. It is not preferable because it circulates and accumulates throughout the plant.

[0003]

SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems found in the conventional method and to provide a method for obtaining high-purity bisphenol A having an excellent hue.

[0004]

The present inventors have completed the present invention as a result of intensive studies to solve the above problems.

That is, according to the present invention, bisphenol A
After washing the crystalline adduct of bisphenol with phenol with phenol, and removing phenol from the crystalline adduct to obtain bisphenol, after contacting industrial phenol with a strong acid ion exchange resin as the washing phenol , A bisphenol A having an excellent hue characterized by using a purified phenol obtained by a distillation treatment
A method of manufacturing the same is provided.

The crystal adduct of bisphenol A and phenol used in the present invention is produced by a conventionally known method. That is, excess phenol and acetone are reacted in the presence of an acid catalyst to obtain a reaction product containing bisphenol A, and the reaction product is crystallized to give a crystalline adduct of bisphenol A and phenol. Can be obtained.

In the present invention, the crystal adduct thus obtained is subjected to a cleaning treatment using industrial phenol purified by a specific method. The present inventors have conducted intensive studies on an industrial phenol purification method for obtaining a phenol suitable for washing a crystal adduct, and after the industrial phenol is brought into contact with a strong acid ion exchange resin, it is subjected to a distillation treatment. The purified phenol obtained does not contain the coloring-causing substance of the product bisphenol A. The product bisphenol A obtained by washing the crystal adduct with this purified phenol and removing the phenol from the washed crystal adduct has an extremely high hue. I found it to be excellent. As the industrial phenol, a commercially available product may be used, and generally, phenol having a purity of 99.5% by weight or more, preferably 99.93% by weight or more may be used.

In the present invention, this industrial phenol is treated by contact with a strong acid type ion exchange resin. As the strong acid type ion exchange resin, one having a sulfone group is used, and such a strong acid type ion exchange resin is well known in the art. For example, Amberlite and Amberlyst available from Nippon And Haas Co., Ltd., or DIAION available from Mitsubishi Kasei Co., Ltd. can be preferably used. The treatment of phenol with this strong acid ion exchange resin is carried out by a method of circulating phenol in a packed column containing a strong acid ion exchange resin, a method of stirring by adding phenol to a stirring tank containing a strong acid ion exchange resin, or the like. Can be implemented. The processing temperature is 45 to 150,
It is preferably 50 to 80 ° C. The contact time between the strong acid ion exchange resin and the phenol is 5 to 200 minutes, preferably 15 to 60 minutes. When phenol is treated using this strong acid ion exchange resin, the water content in phenol is 0.5% by weight or less, preferably 0.1% by weight or less. If the water content is larger than this, the effect of removing impurities by the strong acid ion exchange resin deteriorates. The water content up to 0.5% by weight or less can be removed from phenol by azeotropically adding a known azeotropic agent to phenol.

The phenol which has been subjected to the contact treatment with the strong acid ion exchange resin contains high-boiling point impurities, and the high-boiling point impurities are separated by distillation treatment. The operating conditions of the distillation column should be such that phenol and high-boiling impurities can be separated, but it is necessary to do so under conditions that high-boiling impurities are not mixed in the distillate phenol. Is. The operating pressure is arbitrarily set at a temperature of 185 ° C. or lower, but is usually performed under a reduced pressure of 50 Torr to 600 Torr. If the operating temperature exceeds 185 ° C, decomposition of high-boiling impurities and the like will occur and the quality of the purified phenol will deteriorate, which is not preferable. The purified phenol obtained by the above treatment has an APHA standard hue of 10 or less, and even if it adheres to the product bisphenol, the hue is not particularly deteriorated.

The cleaning of the crystal adduct with the purified phenol may be any method that can sufficiently bring the contact between the crystal adduct and the purified phenol. This washing treatment is carried out, for example, by removing the mother liquor from the crystal adduct in a solid-liquid separator such as a filter or a centrifuge for separating the crystal adduct, and then introducing purified phenol into the solid-liquid separator. It is also possible to wash the crystal adduct to which a small amount of mother liquor discharged from the solid-liquid separation device adheres with purified phenol in another stirring tank. The ratio of the purified phenol to the crystal adduct is 10
The amount is 30 to 1000 parts by weight, preferably 100 to 300 parts by weight, relative to 0 parts by weight. The purified phenol after being used for washing the crystal adduct is used as it is or after being used for washing the crude crystal adduct obtained in the crystallization step of the previous stage, and then is circulated as a raw material phenol in the synthesis reaction step of bisphenol A.

The crystalline adduct washed with the above-mentioned purified phenol has purified phenol adhering to the surface thereof, which is sent from the crystalline adduct to the phenol removal step where phenol is removed and The pure product bisphenol A is recovered. Removal of phenol from the crystal adduct can be carried out by a conventionally known method, for example, a method such as distillation, extraction or steam stripping.

[0012]

According to the present invention, a product bisphenol A having an excellent hue can be obtained. In the present invention, since the purified product of industrial phenol is used as the cleaning liquid for the crystal adduct without using the phenol separated from the crystal adduct, there are the following advantages. (1) Since an adduct free from impurities, particularly impurities that cause coloring, is obtained, a product of high purity and excellent hue, bisphenol, can be obtained. (2) Since no solvent is mixed in the cleaning liquid, the cleaning liquid can be recycled as it is to the reaction system or the crystallization system.

[0013]

EXAMPLES Next, the present invention will be described in more detail by way of examples. A mixture of bisphenol A having a melting color of 50 APHA, phenol, and impurities can be obtained by reacting phenol with acetone in the presence of an acid catalyst by a known method.

Example 1 Bisphenol A having a melting color of 50 APHA obtained by reacting phenol with acetone in the presence of an acid catalyst,
A mixture of phenol and impurities was crystallized to deposit an adduct. This slurry solution was filtered under reduced pressure, and the purified phenol obtained by the method described below was washed with 2.5 parts by weight per 1 part by weight of the adduct. The adduct thus obtained was stripped with steam at 175 ° C. and 25 torr for 30 minutes to substantially completely remove the phenol to obtain bisphenol A. This bisphenol A
As shown below, the hue was extremely good. The purified phenol used above had a melt color of 6APHA.
Commercially available industrial phenol (water concentration: 0.1
wt%, an impurity concentration of 0.05 wt%) was subjected to contact treatment using Amberlite IR-118H + resin manufactured by Rohm and Haas at a temperature of 80 ° C. and a contact time of 50 minutes, and the distillation column bottom temperature was 175 ° C. and the column top pressure was 560 torr. It was obtained by distillation at.

Comparative Example 1 A mixture of bisphenol A having a melt color of 50 APHA, phenol and impurities was crystallized to deposit an adduct. This slurry solution was filtered under reduced pressure to obtain an adduct of 19
The phenol recovered by decomposing at 0 ° C. was washed with 2.5 parts by weight per 1 part by weight of the adduct. The adduct thus obtained was steam stripped at 175 ° C. and 25 Torr for 30 minutes to obtain bisphenol A from which substantially all of the phenol had been removed.
It was 0 APHA.

Comparative Example 2 Bisphenol A was obtained in the same manner as in Example 1 except that the bottom temperature of the distillation column was 200 ° C. when the purified phenol was distilled, and this had a melt color of 30 APHA. The melting colors at 175 ° C. of bisphenol A obtained in the above Examples and Comparative Examples are summarized in the following table.

[Table 1]

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Makoto Yasui Makoto Yasui, 2-12-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kako Construction Co., Ltd. Chome 12-1 Chiyoda Kakoh Construction Co., Ltd. (72) Inventor Noriyuki Yoneda 2-12-1 Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Chiyoda Kakoh Construction Co., Ltd.

Claims (3)

[Claims] 1. A method in which a crystalline adduct of bisphenol A and phenol is washed with phenol and then phenol is removed from the crystalline adduct to obtain bisphenol A. Industrial phenol is a strong acid ion as the washing phenol. A method for producing bisphenol A having an excellent hue, which comprises using purified phenol obtained by contacting with an exchange resin and then subjecting it to a distillation treatment. 2. The method according to claim 1, wherein an industrial phenol having a water content of 0.5% by weight or less is brought into contact with a strong acid type ion exchange resin and then distilled. 3. The method according to claim 1, wherein the distillation temperature is 185 ° C. or lower.