JP3173732B2 - Method for producing bisphenol A with excellent hue - Google Patents

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 color. Bisphenol A is a raw material for polycarbonate resins and epoxy resins. In recent years, the demand for colorless, transparent and high-purity bisphenol A particularly suitable for optical applications has been remarkably increased.

[0002]

BACKGROUND OF THE INVENTION Bisphenol A [2.2
-Bis (4-hydroxyphenyl) propane] is known to react excess phenol with acetone in the presence of an acid catalyst. Further, in order to separate and recover high-purity bisphenol A from the 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 its crystalline adduct,
It is also affected by impurities other than phenol contained in the adduct crystals. In order to remove impurities other than phenol contained in the crystal adduct, a method of washing the adduct crystal with liquid phenol is known (Japanese Patent Laid-Open Publication No. Hei 1-1990).
No. 146839). This known method is characterized in that phenol separated from a crystalline adduct is used as a liquid phenol for washing, thereby obtaining a product bisphenol A having a better hue than using industrial phenol. In this case, the phenol is separated from the crystalline adduct by evaporation, extraction, stripping with steam, or the like. As a method for removing phenol from a crystal adduct by evaporation, specifically, Japanese Patent Publication No. Sho 52-4
As disclosed in US Patent 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 obtain bisphenol A.
Can be mentioned. However, such a method has the following problems and has not been satisfactory yet. (1) In the phenol separated by evaporation or steam stripping, there are impurities such as chroman and 2,4'-bisphenol A contained in the adduct itself, and coloring causes such as isopropenylphenol generated by heating in the separation step. Is mixed. This is particularly noticeable at high evaporation temperatures. If phenol mixed with these impurities is used for adduct cleaning, bisphenol A having high purity and good hue cannot be obtained. (2) When the solvent extraction method is used, equipment and utility for separating the solvent and phenol are required. In addition, the solvent is mixed into the phenol separated by the solvent extraction, and the solvent is removed together with the washed phenol. 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-mentioned problems in the conventional method and to provide a method for obtaining high-purity bisphenol A having excellent hue.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have completed the present invention.

That is, according to the present invention, bisphenol A
A method for obtaining bisphenol A by washing a crystalline adduct of phenol and phenol with phenol and then removing phenol from the crystalline adduct, wherein the washing phenol has a purity of 99.5 weight% with a water content of 0.5% by weight or less. %
After the above industrial phenol is brought into contact with a strong acid type ion exchange resin, the APHA standard hue obtained by subjecting it to a distillation treatment at a temperature of 185 ° C. or less under a condition of 50 to 600 Torr is 10
A method for producing bisphenol A having excellent hue, characterized by using the following purified phenol, is provided.

The crystalline adduct of bisphenol A and phenol used in the present invention is produced by a conventionally known method. That is, an 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 subjected to a crystallization treatment to obtain a crystal adduct of bisphenol A and phenol. Can be obtained.

In the present invention, the crystalline adduct thus obtained is subjected to a washing treatment using an 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 crystalline adduct.As a result, the industrial phenol was brought into contact with a strong acid-type ion exchange resin, and then subjected to a distillation treatment. The resulting purified phenol does not contain the coloring agent of the product bisphenol A, and the product bisphenol A obtained by washing the crystalline adduct with this purified phenol and removing phenol from the washed crystalline adduct has an extremely high hue. I found it to be excellent. As the industrial phenol, commercially available products can be used, and generally, phenol purity of 99.5% by weight or more, preferably 99.93% by weight or more may be used.

In the present invention, the industrial phenol is treated by contacting it with a strong acid type ion exchange resin. As the strong acid type ion exchange resin, a resin 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 Amberlist available from Nippon And Haas Co., Ltd., and Diaion available from Mitsubishi Kasei Corporation can be preferably used. The treatment of phenol using this strong acid-type ion exchange resin is carried out by a method in which phenol is passed through a packed tower containing strong acid-type ion-exchange resin, a method in which phenol is put into a stirring tank containing strong acid-type ion-exchange resin, and stirred. Can be implemented. Processing temperature is 45-150,
Preferably it is 50-80 degreeC. The contact time between the strong acid type ion exchange resin and phenol is 5 to 200 minutes, preferably about 15 to 60 minutes. When phenol is treated using this strong acid-type ion exchange resin, the water content in the phenol is adjusted to 0.5% by weight or less, preferably 0.1% by weight or less. If the water content is higher than this, the effect of removing impurities by the strong acid-type ion-exchange resin deteriorates. Removal of water up to 0.5% by weight or less from phenol can be performed by adding a known azeotropic agent to phenol and causing phenol to azeotrope.

The phenol that has been subjected to the contact treatment with the strong acid-type ion exchange resin contains high-boiling impurities, and the high-boiling impurities are separated as distillation residues by distillation. The distillation column may be operated under conditions in which phenol and high-boiling impurities can be separated, but the distillation column must be operated under conditions in which high-boiling impurities are not mixed into the phenol distilled off. It is. If the temperature is 185 ° C. or lower, the operating pressure is arbitrarily set, but the operation 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 be deteriorated. The purified phenol obtained by the above treatment has an APHA standard hue of 10 or less, and does not particularly deteriorate the hue even if it adheres to the product bisphenol.

The washing of the crystal adduct with the purified phenol may be carried out by any method capable of sufficiently bringing the crystal adduct into contact with the purified phenol. In this washing treatment, for example, after removing the mother liquor from the crystal adduct in a solid-liquid separation device such as a filter or a centrifugal separator for separating the crystal adduct, purified phenol is introduced into the solid-liquid separation device. And a crystal adduct to which a small amount of mother liquor discharged from the solid-liquid separation device adheres can be washed with purified phenol in a separate stirred tank. The ratio of purified phenol to crystal adduct used was
The proportion is 30 to 1000 parts by weight, preferably 100 to 300 parts by weight, based on 0 parts by weight. The purified phenol used after washing the crystal adduct is used as it is or as a raw phenol in a bisphenol A synthesis reaction step after being used for washing a crude crystal adduct obtained in the preceding crystallization step.

The crystal adduct washed with the purified phenol has purified phenol adhered to its surface. The purified phenol is sent to the phenol removal step from the crystal adduct, where the phenol is removed. The pure bisphenol A product is recovered. Removal of phenol from the crystal adduct can be performed 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 a purified product of industrial phenol is used as the washing liquid for the crystal adduct without using phenol separated from the crystal adduct, the following advantages are obtained. (1) Since an adduct free from impurities, particularly impurities that cause coloring, is obtained, a product bisphenol having high purity and excellent hue can be obtained. (2) Since no solvent is mixed in the cleaning liquid, the cleaning liquid can be circulated and used as it is in the reaction system or the crystallization system.

[0013]

Next, the present invention will be described in more detail with reference to examples. A mixture of bisphenol A, phenol and impurities having a melt color of 50 APHA 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 melt color of 50 APHA, obtained by reacting phenol and acetone in the presence of an acid catalyst,
A mixture of phenol and impurities was crystallized to precipitate an adduct. This slurry solution was filtered under reduced pressure, and the purified phenol obtained by the method described later was washed with 2.5 parts by weight per 1 part by weight of the adduct. The adduct thus obtained was subjected to steam stripping at 175 ° C. and 25 torr for 30 minutes to substantially completely remove phenol, thereby obtaining bisphenol A. This bisphenol A
Was very good in hue as described below. In addition, the purified phenol used above was molten color 6APHA.
Commercial phenol (water concentration 0.1
wt%, impurity concentration 0.05 wt%) using Amberlite IR-118H + resin manufactured by Rohm and Haas Co., at a temperature of 80 ° C. for a contact time of 50 minutes, and a distillation column bottom temperature of 175 ° C. and a top pressure of 560 torr. It was obtained by distillation.

Comparative Example 1 A mixture of bisphenol A, phenol and impurities having a melting color of 50 APHA was crystallized to precipitate an adduct. The slurry solution was filtered under reduced pressure, and the adduct was filtered.
The phenol recovered by decomposition at 0 ° C. was washed with 2.5 parts by weight based on 1 part by weight of the adduct. The thus obtained adduct was subjected to steam stripping 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 distillation column bottom temperature was set to 200 ° C. when distilling the purified phenol, but the melting color was 30 APHA. The following table summarizes the melt color of bisphenol A obtained at 175 ° C. in the above Examples and Comparative Examples.

[Table 1]

Continued on the front page (72) Inventor Makoto Yasui 2-2-1, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Chiyoda Chemical Works (72) Inventor Sachio Asaoka 2--12, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa No. 1 Inside Chiyoda Chemical Works, Ltd. (72) Inventor Noriyuki Yoneda 2-1-1, Tsurumi Chuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Chiyoda Chemical Works, Ltd. (56) References JP-A-58-79942 (JP, A) JP-A-47-30628 (JP, A) JP-B-52-42790 (JP, B2) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 39/16 C07C 37/82 C07C 37/84 CA (STN) REGISTRY (STN)

Claims (1)

(57) [Claims] 1. A method of obtaining a bisphenol A by washing a crystalline adduct of bisphenol A and phenol with phenol and then removing phenol from the crystalline adduct, wherein the washing phenol has a water content of 0.5%.
After contacting an industrial phenol having a purity of 99.5% by weight or less with a strong acid-type ion exchange resin at a temperature of 185 ° C. or less and a distillation treatment under a condition of 50 to 600 Torr, the APHA standard hue is 10% or less. A method for producing bisphenol A having excellent hue, comprising using the following purified phenol.