JP3041547B2 - Method for separating high purity bisphenol A - 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 separating bisphenol A having a high purity and excellent color from a crystalline adduct of bisphenol A and phenol. 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. On the other hand, in order to separate phenol from the crystalline adduct,
A method of melting at 20 ° C., evaporating the melt at a temperature above 180 ° C. and under reduced pressure, and separating and condensing the obtained vapor to separate bisphenol A from phenol is known (Japanese Patent Publication No. Sho 52). -42790). In such a method for separating phenol from a crystalline adduct, the purity of the obtained bisphenol A depends not only on the purity of the crystalline adduct itself but also on the phenol removal rate. There is a problem that the hue of the product bisphenol A deteriorates because it is impossible to prevent a small amount of the coloring cause substance from being mixed into the product bisphenol A to be obtained. The problem of hue deterioration (coloring) is inevitable as long as the heat treatment is used, because the coloring causative substance is caused by the melting of the crystal adduct and the heating during the evaporation of the melt. Was thought.

[0003]

SUMMARY OF THE INVENTION An object of the present invention is to solve the above-mentioned problems in the prior art and to provide a method for separating high-purity bisphenol A having an excellent hue from a crystalline adduct.

[0004]

Means for Solving the Problems The present inventors have conducted intensive studies to solve the above-mentioned problems, and as a result, have found that bisphenol A
The present inventors have found that the amount of the coloring causative mixed into the material can be remarkably reduced by removing oxygen attached to the surface of the material constituting the melting tank of the crystal adduct and the inner wall surface in the evaporator, and completed the present invention. I came to.

That is, according to the present invention, bisphenol A
The crystal adduct of phenol and phenol is supplied to an apparatus system including a melting device and an evaporator, the crystal adduct is melted in the melting device, and the melt of the crystal adduct is evaporated in the evaporator to exchange bisphenol A and phenol. In the method of separating into, at least the amount of oxygen attached to the inner wall of the melting device and the evaporator included in the device system,
After removing to less than 10 mmol per 1 m ^{2 of} inner wall surface by washing with an organic solvent, a crystal adduct is supplied to the apparatus system,
There is provided a method for separating high-purity bisphenol A, which comprises melting and evaporating.

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. The crystalline adduct thus obtained is preferably subjected to a washing treatment using phenol in order to increase its purity. The present inventors have conducted intensive research on an industrial phenol purification method for obtaining phenol suitable for washing a crystalline adduct, and as a result, after contacting industrial phenol with a strong acid-type ion exchange resin,
The purified phenol obtained by the distillation treatment does not contain a coloring agent of the product bisphenol A, and the product bisphenol A obtained by washing the crystal adduct with the purified phenol and removing phenol from the washed crystal adduct is It was found that the hue was extremely excellent. As the industrial phenol, a commercially available product can be used, and generally, phenol purity is 99.5% by weight.
It is preferable that the amount is at least 99.93% by weight. Hereinafter, the purification of the industrial phenol will be described in detail.

As the strong acid type ion exchange resin used for the treatment of industrial phenol, 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, gel type materials such as Amberlite and Amberlist available from Nippon & Haas Co., Ltd., and Diaion available from Mitsubishi Kasei Co., Ltd. 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. The processing temperature is 45 to 150, preferably 50 to 80C. The contact time between the strong acid type ion exchange resin and phenol is 5-20.
0 minutes, preferably about 15 to 60 minutes. When performing phenol treatment using this strong acid ion exchange resin,
The water content in the phenol is 0.5% by weight or less, preferably 0.1% by weight or less. With more water,
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 contacted with the strong acid-type ion exchange resin contains high-boiling impurities, and the high-boiling impurities are separated as distillation residues by distillation. As the distillation apparatus, an ordinary packed column, a tray column, a thin film evaporator, or the like can be used alone or in combination.
The operating conditions of this evaporator may be such that phenol and high-boiling impurities can be separated, but it is necessary to carry out the conditions under which high-boiling impurities are not mixed into the distilled phenol. That 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 crystalline adduct with the purified phenol may be carried out by any method capable of sufficiently bringing the crystalline 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.

[0010] The crystal adduct obtained as described above is treated using a system for removing phenol from the crystal adduct including a melting device and an evaporation device. In the present invention, prior to the treatment, In advance, an oxygen removal treatment is applied to at least the surface of the material constituting the inner wall surfaces of the melting device and the evaporator included in the phenol removal device. The inner wall surfaces of the melting device and the evaporator,
Metal material, usually stainless steel, for example, SUS
304, are formed in SUS316,316L etc., on its surface, typically, the oxygen of about 1 m ² per 30 to 60 millimoles attached bond. This amount of oxygen can be measured by various methods. For example, there is a method of estimating by correlating the cleaning conditions with the test piece and the amount of surface-bonded oxygen whose depth is measured by surface etching, but it is also measured from the relationship between the surface-bonded oxygen amount and the coloring of the cleaning phenol. it can. In the case of other cleaning liquids, the correlation between the coloring and the amount of oxygen adhering to the surface can be determined in advance and used as a measuring method. For example, the color of phenol is 6 APHA / parts per million oxygen and can be used as a correlation in this measurement. According to the study of the present inventors, the melting device and the evaporating device are:
When the oxygen adhering to the inner wall surface is removed before use, it can significantly suppress the generation of coloring-causing substances caused by the melting of the crystalline adduct and the heating in the evaporation of the melt, and the product bisphenol with good hue can be obtained. It was found to be obtained.

The removal of oxygen from the inner wall surfaces of the melting device and the evaporator can be performed by washing the inner wall surface with an organic solvent. As the organic solvent, phenol or bisphenol A, a mixture of phenol and bisphenol A, or the like can be used. The cleaning temperature is
The temperature is 100 to 200 ° C, preferably 120 to 185 ° C. As an atmosphere for cleaning, a non-oxidizing gas atmosphere such as nitrogen gas, nitrogen gas, argon gas, or degassed steam or a reduced pressure atmosphere is used, and the oxygen concentration in the atmosphere is 0.01 vol% or less, preferably 0.1 vol% or less. 005vol
%, More preferably 0.001% by volume or less. The cleaning of the inner wall surface with the organic solvent can be performed by spraying the inner wall surface with the organic solvent through a spray nozzle. After washing with the organic solvent, the organic solvent remaining at the bottom of the melting device and the evaporator is discharged,
If necessary, dry the inside. The oxygen concentration in the gas phase can be measured using a trace gas oxygen analyzer using a usual gas chromatography method or electrochemical method.

The treatment for removing oxygen from the inner wall surface is performed so that the amount of oxygen adhering to the inner wall surface is 10 mmol or less, preferably 5 mmol or less per 1 m ^{2 of} the inner wall surface. As the melting device, a closed container of an external heating system having a heating jacket on an outer wall surface, a closed container of an internal heating system having a heating coil inside, or the like is used. As the evaporator, a distillation column, a stripper, a centrifugal thin-film evaporator, or the like is used. A pipe is provided between the melting device and the evaporator, and a discharge tube for bisphenol A is provided in the evaporator.
It is preferable to perform an oxygen removal treatment on these pipe inner wall surfaces in the same manner as described above. In the present invention, as described above, at least the melting device and the evaporator included in the apparatus system are subjected to the oxygen removal treatment attached to the inner wall surface thereof, and then the crystal adduct is supplied to the apparatus system. Then, the crystal adduct is melted by a melting device, and the obtained melt is evaporated by an evaporator to remove phenol by evaporation. The operating conditions of the melting device are as follows: temperature: 115 to 18
0 ° C, preferably 120 to 150 ° C, pressure: normal pressure, oxygen concentration: 0.01 vol% or less, preferably 0.005 v
ol% or less, more preferably 0.001 vol% or less. The evaporator can be used in one stage or in multiple stages. When used in one stage, the operating conditions of the one-stage evaporator and the last stage evaporator in the case of using multiple stages are 180 to 200 ° C. , Preferably 170
１８185 ° C., pressure: 1１００100 Torr, preferably 5５〜100 Torr
The conditions of 40 Torr and oxygen concentration in the atmosphere: 0.005 vol% or less, preferably 0.001 vol% or less are employed.

[0013]

According to the present invention, it is possible to remarkably suppress the amount of a coloring causative substance caused by heating at the time of melting a crystalline adduct and evaporating the melt, and to obtain a high-purity bisphenol A having a good hue. Can be obtained.

[0014]

Next, the present invention will be described in more detail with reference to examples.

Example An externally heated SUS304 sealed container was used as a melting device, and a SUS304 stripping device was used as an evaporator. A crystal adduct supply pipe is attached at the top of the melting device, and a melt pipe is attached at the bottom,
This melt pipe was connected to an intermediate portion of the stripping device. A pipe for discharging phenol vapor was provided at the top of the stripping apparatus, and a pipe for discharging the melt of bisphenol A was provided at the bottom. The above-mentioned pipes were all made of SUS304. next,
In the apparatus system configured as described above, the inner wall surface of the melting device, the inner wall surface of the stripping device, the pipe between the melting device and the stripping device, and the liquid of bisphenol A melting attached to the stripping device. The inner wall surface of the discharge pipe was cleaned as follows. (1) Cleaning of Inner Wall of Melting Apparatus A phenol solution of 130 ° C. is sprayed onto the inner wall under normal pressure through a spray nozzle to sufficiently wash the inner wall, and then a phenol / bisphenol A mixed solution of 150 ° C. ( (Mixing weight ratio: 65/35) was sprayed to sufficiently wash the inner wall surface. (2) Cleaning of the inner wall surface of the stripping apparatus At normal pressure, phenol at 130 ° C was flowed from a spray nozzle attached to the upper part of the apparatus to wash the center of the apparatus, and then phenol at 130 ° C and then at 150 ° C. Phenol / bisphenol A mixture (mixing weight ratio = 65)
/ 35), so that the device wall was sufficiently circulated. Then, a phenol / bisphenol A mixture (mixing weight ratio = 65/35) at 180 ° C. and 10 Torr.
Was distributed. (3) Washing of inner wall of pipe The phenol at 130 ° C. was passed through the pipe and washed.
At that time, care was taken so that no gas phase was present on the inner wall surface of the tube.

By the above-mentioned cleaning, it was confirmed that the amount of oxygen adhering to the inner wall surface of each device and piping was 5 mmol or less per 1 m ^{2 of} inner wall surface. Next, as described above, a purified crystal manufactured as follows using a device in which the melt of the crystal adduct and the melt of bisphenol A are brought into contact with each other and a device system in which the inner wall surfaces of the pipes are previously deoxygenated. The phenol was evaporated from the adduct (melted APHA: 5) to separate bisphenol A. (Production of Crystal Adduct) A mixture of bisphenol A, phenol and impurities having a melting color of 50 APHA obtained by reacting phenol and acetone in the presence of an acid catalyst was crystallized to precipitate an adduct. The 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.
A purified crystal adduct was obtained. Note that the purified phenol used above was of 6 APHA in molten color, and was commercially available industrial phenol (water content: 0.1 wt%, impurity concentration: 0.0
Amberlite I manufactured by Rohm and Haas Company
80 ° C., contact time 50 using R-118H + resin
Minutes, the distillation column bottom temperature is 175 ° C., and the column top pressure is 56
It was obtained by distillation at 0 torr. The operating conditions of the melting device and the stripping device in the above are as follows. (Melting device) Temperature: 130 ° C Pressure: Normal pressure Atmospheric oxygen concentration: 0.0005 vol% (Stripping device) Temperature: 175 ° C Pressure: 10 Torr Atmospheric oxygen concentration partial pressure: 0.0015 vol%

Comparative Example 1 An experiment was conducted in the same manner as in Example 1, except that the inner walls of the melting device, the stripping device, and the piping were not subjected to cleaning treatment. Next, the melting color of the bisphenol A obtained in Example 1 and Comparative Example 1 at 175 ° C. is shown in the following table.

[0018]

[Table 1]

──────────────────────────────────────────────────続 き Continuing on the front page (72) Inventor Nobuhiro Onda 2-1-1, Tsurumichuo, Tsurumi-ku, Yokohama-shi, Kanagawa Prefecture Inside Chiyoda Kako Construction Co., Ltd. No. 12-1, Chiyoda Chemical Works, Ltd. (56) References JP-A-5-32577 (JP, A) JP-A-5-39239 (JP, A) JP-A-5-39237 (JP, A) JP 38-18371 (JP, B1) JP-B 45-39251 (JP, B1) (58) Fields investigated (Int. Cl. ⁷ , DB name) C07C 37/74 C07C 37/82 C07C 37/84 C07C 39/16 C07C 63/00

Claims (2)

(57) [Claims] 1. A crystal adduct of bisphenol A and phenol is supplied to a system including a melting device and an evaporator, the crystal adduct is melted in the melting device, and the melt of the crystal adduct is evaporated in the evaporator. removal in a method for separating bisphenol a and phenol with one another, the amount of oxygen attached to at least the melting device and the evaporator in a wall included in the device system, the organic solvent washing, below the inner wall surface 1 m ² per 10 mmol Te After doing
A method for separating high-purity bisphenol A, comprising supplying a crystal adduct to the apparatus system and subjecting the same to melting and evaporation. 2. The method according to claim 1, wherein said crystalline adduct is obtained by bringing an industrial phenol into contact with a strong acid-type ion exchange resin and then washing with a purified phenol obtained by a distillation treatment.