JP2000344699A - Production of bisphenol a - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a process for producing high-purity bisphenol A containing decreased amount of thermal degradation substance, causal substance for discoloration and coloring substance with decreased number of melting and crystallization steps using a catalyst having high activity and selectivity, a small-sized reactor and decreased amount of catalyst. SOLUTION: Bisphenol A having high purity is produced by reacting acetone with phenol in the presence of an organic polymer siloxane having a hydrocarbon group containing sulfonic acid group and both of a hydrocarbon group containing mercapto group, cooling the reaction mixture containing bisphenol A to form crystal of the adduct of bisphenol A and phenol, separating the adduct crystal from the slurry, removing impurities by fractional melting and crystallization treatment to obtain a purified adduct crystal and finally removing phenol from the purified adduct crystal.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

TECHNICAL FIELD The present invention relates to a bisphenol A
And a method for producing the same. More specifically, the present invention relates to a method for producing high-purity bisphenol A from phenol and acetone in the presence of an organic polymer siloxane having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group.

[0002]

2. Description of the Related Art Bisphenol A [2,2-bis (4-
[Hydroxyphenyl) propane] (also referred to as p, p'-bisphenol) is usually produced by subjecting phenol and acetone to a dehydration condensation reaction in the presence of a homogeneous acid catalyst or a solid acid catalyst. As a typical solid acid catalyst, a sulfonic acid type cation exchange resin is used, and further, by coexisting a compound containing a mercapto group in the reaction system, it is possible to improve catalyst activity and selectivity. Are known. Specifically, a method in which a free mercapto group-containing compound such as an alkyl mercaptan is flown together with phenol and acetone as raw materials in a fixed bed reactor filled with a sulfonic acid type cation exchange resin (Japanese Patent Publication No. 45-10337) ), A method of covalently bonding a part of the sulfonic acid group of the sulfonic acid type cation exchange resin and the mercapto group-containing compound, and ionizing the part of the sulfonic acid group of the sulfonic acid type cation exchange resin and the mercapto group-containing compound. There is a method of joining by joining.

Under such a catalyst, bisphenol A produced from phenol and acetone is usually obtained as a large excess phenol solution. After partially distilling phenol from this reaction mixture by distillation, an adduct, which is an addition mixture of bisphenol A and phenol, is precipitated in a crystallizer, and the adduct is redissolved with phenol and crystallized again. A method is known in which an adduct is obtained in a vessel, and then phenol is distilled off from the adduct by distillation to obtain a granulated product of bisphenol A.

[0004] However, in order to purify bisphenol A, phenol is used as a recrystallization solvent and crystallization is performed in multiple stages, so that there is a drawback that equipment costs are high.

[0005] Also, after removing the major excess of phenol by distillation from the reaction mixture, crude bisphenols containing less than 10%, preferably less than 3%, of the phenol thus obtained, such as Rittner and St
Iner, Chem. Ing. Techn. 63 (1
991), 881; a falling film crystallizer of the type described in US Pat.
It is also known that high-purity bisphenol A can be produced by purification by fractional melt crystallization using an iser. This method has the disadvantage that very large amounts of phenol must first be removed by distillation, resulting in high costs and prolonged exposure of the bisphenol A and by-products to heat. On the other hand, the resulting crude bisphenols are generally of very low purity, which requires subsequent multi-stage melt crystallization until high purity is achieved.

Further, as a method for solving such a drawback, an adduct of bisphenol A and phenol is obtained by crystallization from the reaction mixture obtained by a known method in the presence of an acidic catalyst, and then the adduct is added to the adduct. A method for producing high-purity bisphenol A by adding phenol so that the total phenol content is at least 40% and fractionally melt-crystallizing the mixture in the presence of an inert gas has been disclosed (Japanese Patent Application Laid-Open No. Hei 6 (1994) -6380). -25048). An example is described in which an acidic ion exchanger is used as an acidic catalyst and melt crystallization is applied.

However, since the sulfonic acid type cation exchange resin as the acid catalyst has a low catalytic activity and a high by-product selectivity, the reactor is very large and the amount of the catalyst used is large.
Further, the disadvantage that the number of melt crystallization steps is as large as two or more still remains, and there is a difficulty in industrially implementing the method. In recent years, bisphenol A has been required to have a very small heat denaturation and no coloration. Therefore, there is a strong demand for a method for producing bisphenol A in which the causative substance of heat denaturation and coloring is reduced. Was.

[0008]

SUMMARY OF THE INVENTION The present invention uses a novel catalyst having a high activity and a high selectivity, a small reactor, a small amount of a catalyst, a small number of melt crystallization steps, and a thermal denaturation. An object of the present invention is to provide a process for producing high-purity bisphenol A in which substances, substances causing coloring and coloring substances are reduced.

[0009]

Means for Solving the Problems The inventors of the present invention have conducted intensive studies to solve the above-mentioned problems. As a catalyst for reacting phenol and acetone, first, a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group are used. An adduct of bisphenol A and phenol (adduct) is obtained from the obtained phenol solution of bisphenol A by crystallization using an organic polymer siloxane catalyst having both phenol and phenol. That the purpose is achieved by fractional melt crystallization of
The present invention has been completed.

That is, according to the present invention, acetone and phenol are reacted in the presence of an organic high molecular siloxane having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group to form bisphenol A. The obtained reaction mixture is cooled to generate adduct crystals of bisphenol A and phenol, and after separating the adduct crystals from the slurry, impurities are removed by fractional melt crystallization to obtain purified adduct crystals. A method for producing bisphenol A, characterized in that phenol is removed from the obtained purified adduct crystals to obtain high-purity bisphenol A.

[0011]

BEST MODE FOR CARRYING OUT THE INVENTION As the phenol used as a raw material in the present invention, commercially available industrial phenol can be used, but it is preferable to use a phenol previously treated with a strong acid type cation exchange resin. More preferably, it is obtained by treating with a strong acid type cation exchange resin and further purifying by distillation.

The industrial phenols include those produced by the cumene method or the toluene oxidation method, but may be produced by any method. Generally, phenols with a purity of 98% or more are commercially available.

The strong acid type cation exchange resin used for the treatment of phenol may be a commonly available one, such as Diaion manufactured by Mitsubishi Chemical Corporation, Amberlite and Amberlyst manufactured by Rohm and Haas, and Levatit manufactured by Bayer. Is mentioned. As the strong acid type cation exchange resin, any of a gel type and a macroporous type can be used, but a gel type having a degree of crosslinking of 2 to 8% is preferable because it can be used stably for a long period of time.

[0014] The phenol is treated continuously or batchwise with the strong acid type cation exchange resin as described above. The method of filling the packed column with the strong acid type cation exchange resin and continuously flowing the phenol is a method of treating the resin. It is preferable because crushing is small and phenol can be efficiently treated. Processing temperature is 41 ~ 1
The temperature is 50C, preferably 50C to 120C. The time for treating phenol with a strong acid type cation exchange resin is 5 minutes to
10 hours, preferably 10 minutes to 2 hours.

The distillation method is not particularly limited, but the distillation is preferably carried out at normal pressure to 10 mmHg and at a temperature of 70 to 200 ° C.

[0016] The purified phenol thus obtained is introduced into a reactor. The purified phenol is then preferably introduced into the reactor without contact with oxygen. The purified phenol may be sent directly to the reactor and reacted with acetone, or may be used in another step in a series of bisphenol A production processes and then sent to the reactor and reacted with acetone.

The acetone used in the present invention is not particularly limited, and commercially available commercially available acetone may be used. Generally, those having a purity of 99% or more are available.

In the production of bisphenol from phenol and acetone as described above, the present invention uses a novel organic polymer siloxane catalyst having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group. An organic polymer siloxane catalyst having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group has higher activity and higher selectivity than a modified ion exchange resin, and is an excellent catalyst. Examples of the organic polymer siloxane catalyst having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group are described in JP-A-8-208545 and JP-A-9-110.
No. 989 and JP-A-10-225638, a hydrocarbon group partially having a sulfonic acid group and a hydrocarbon group having a mercapto group are directly contained in a silica matrix comprising a siloxane bond. An organic polymer siloxane having a structure in which a silicon atom is bonded to a carbon-silicon bond is exemplified. As a method for preparing such an organic polymer siloxane, for example, (1) an alkoxysilane having a sulfonic acid group-containing hydrocarbon group, an alkoxysilane having a mercapto group-containing hydrocarbon group, and tetraalkoxysilane in an arbitrary ratio (2) a hydrolyzate of a water-soluble alkoxysilane having a sulfonic acid group-containing hydrocarbon group, an alkoxysilane having a mercapto group-containing hydrocarbon group, and tetra A so-called sol-gel method for preparing alkoxysilanes (1) and (2), in which alkoxysilanes are mixed at an arbitrary ratio, and then synthesized by hydrolysis and polycondensation;
(3) A preparation method by so-called silylation in which an alkoxysilane having a mercapto group-containing hydrocarbon group is silylated to a silanol group present in an organic polymer siloxane having a sulfonic acid group-containing hydrocarbon group and the mercapto group is fixed. Are known.

The hydrocarbon group having a sulfonic acid group is less
At least one sulfonic acid group (—SO _ThreeH) having carbonization
Any hydrocarbon group as long as it is a hydrogen group is included in the present invention.
It is possible to use, but preferably a sulfonic acid group
Having at least one and having 1 to 20 carbon atoms
Elementary group. Preferably it has 6 to 20 carbon atoms, more preferably
Preferably at least one sulfo having 6 to 15 carbon atoms
Substituted or unsubstituted aromatic hydrocarbons having a phonic acid group
Groups (even groups in which aromatic groups are directly substituted with sulfonic acid groups,
Sulfonic acid group replaces hydrocarbon group substituted by aromatic group
Any of the following groups); or, preferably,
1 to 15 carbon atoms with at least one sulfonic acid group
Under, more preferably, substitution of 1 to 10 carbon atoms or less
Is from the group consisting of unsubstituted aliphatic and alicyclic hydrocarbon groups
At least one selected hydrocarbon group. like this
Examples of hydrocarbon groups having various sulfonic acid groups include:
Phenyl nucleus substituted by at least one sulfonic acid group
, Tolyl, naphthyl, methylnaphthyl, etc.
Aromatic groups such as aromatic groups, benzyl groups, and naphthylmethyl groups.
Substituted with at least one sulfonic acid group, such as
Methyl, ethyl, n-propyl, i-propyl
Group, n-butyl group, i-butyl group, t-butyl group,
Chain or branched pentyl group, straight or branched hexyl
Group, straight-chain or branched heptyl group, straight-chain or branched
Octyl group, cyclohexyl group, methylcyclohexyl
And an ethylcyclohexyl group. More
Their aromatic or saturated aliphatic or cycloaliphatic hydrocarbons
In addition to sulfonic acid groups, halogen groups, alkoxy groups
Group, nitro group, amino group, hydroxy group, etc.
Hydrocarbon group.

The hydrocarbon group having a mercapto group has at least one mercapto group represented by the descriptive formula --SH.
At least one selected from the group consisting of hydrocarbon groups having 1 to 20 carbon atoms, wherein aliphatic or alicyclic saturated hydrocarbon, unsaturated hydrocarbon or aromatic hydrocarbon is -SH
A hydrocarbon group to which the group is attached. Preferably, an aliphatic or alicyclic saturated hydrocarbon group or an aromatic hydrocarbon group has S
It is a hydrocarbon group having at least one H group bonded thereto. Examples of the hydrocarbon group having such a mercapto group include:
Mercaptoalkyl groups such as mercaptomethyl group, 2-mercaptoethyl group and 3-mercapto-n-propyl group; alicyclic hydrocarbon groups such as 4-mercaptocyclohexyl group and 4-mercaptomethylcyclohexyl group; p-
And mercapto aromatic groups such as a mercaptophenyl group and a p-mercaptomethylphenyl group. Further, these aromatic or aliphatic or alicyclic hydrocarbon groups may be hydrocarbon groups having a substituent such as a halogen atom, an alkoxy group, a nitro group, an amino group or a hydroxy group in addition to a mercapto group. .

The reaction is usually carried out at a molar ratio of phenol to acetone of 2 to 30, preferably 5 to 10. If the molar ratio of phenol to acetone is 2 or more, the residual amount of acetone after the reaction is small,
The generation of impurities such as mesityl oxide by-produced from acetone is reduced. When the molar ratio is 30 or less, the amount of unreacted phenol circulated is reduced, so that equipment such as a reactor and a crystallizer are reduced, and power required for circulation is reduced, which is economical. . The pressure may be such that the phenol and acetone as raw materials do not gasify since the reaction is carried out in a liquid phase, but is usually from normal pressure to 0.
It is performed within a range of 5 MPa (gauge pressure). Reaction temperature is 4
The temperature is 0 to 200 ° C, preferably 50 to 120 ° C. When the reaction temperature is lower than 40 ° C., the reaction time becomes extremely long, and it becomes necessary to install a huge reactor. Reaction temperature 20
If the temperature exceeds 0 ° C., undesirable side reactions occur, and the selectivity decreases. The reaction time is generally 1 minute to 15 hours, preferably 10 minutes to 5 hours.

The reaction solution thus obtained is cooled to 30 to 70 ° C. after removing reaction water, unreacted acetone and a part of unreacted phenol, if necessary, and then bisphenol A and phenol are removed. Equimolar adduct crystals are precipitated, and the adduct is separated by a centrifuge or a filter.

The obtained adduct is melted by heating as it is and is introduced into the subsequent step of separate melting and crystallization, but after dilution with phenol, it can be introduced into the separate melt and crystallizing step. At this time, the total phenol content is at least 40% by weight, preferably 45 to 60%, to obtain a homogeneous solution. From this homogeneous solution, an equimolar adduct of bisphenol A and phenol is fractionally melt-crystallized, and the equimolar adduct of bisphenol A and phenol is highly purified.

The fractional melt crystallization is carried out, for example, using a generally available falling film crystallization apparatus. The dilute bisphenol A phenol solution fractionated by fractional melt crystallization can be repeatedly recycled to this fractional melt crystallization step, or can be recycled to the acetone-phenol reaction step. Preferably the latter,
It is better to use it circulating in the reaction process.

The high-purity bisphenol A and phenol equimolar adduct obtained by fractional melt crystallization are heated and melted, and residual phenol is distilled off to several tens ppm by distillation.
High purity bisphenol A with a purity of 99.9% or more after granulation
Can be obtained.

The present invention using an organic polymer siloxane catalyst having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group has a higher catalyst productivity of bisphenol A than the conventional method using an ion exchange resin catalyst. Therefore, even if the reactor becomes small and the molar ratio of phenol and acetone is small, the conversion ratio and the selectivity are both high, so that the distillation tower, the crystallizer, etc. can be downsized, and the equipment cost is greatly reduced. obtain. Further, by fractional melt crystallization, bisphenol A having a high purity can be produced in a high yield as compared with a conventional production method using an ion exchange resin catalyst.

Furthermore, it was unexpectedly unexpected that the reaction, crystallization / separation and fractional melt crystallization with the organopolymeric siloxane catalyst of the present invention caused coloration of indans, chromans and trisphenols. It has been clarified that substances and coloring substances can be effectively reduced, and a colorless product having much less heat denaturation than before can be produced as a polycarbonate raw material which is a main use of bisphenol A.

[0028]

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

Example 1 [Preparation of catalyst] According to the following procedures (a) and (b),
An organic polymer siloxane catalyst having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group was prepared.

(A) Synthesis of sulfonic acid group-containing alkoxysilane 200 ml of methylene chloride was placed in a two-necked 500 ml round bottom flask equipped with a dropping funnel, and 124.0 g (0.585 mol) of phenyltrichlorosilane was added thereto. Ice cooled. 46.8 g of sulfuric anhydride (0.585 g)
(mol) in 100 ml of methylene chloride was added dropwise over 30 minutes under a nitrogen stream, and the ice bath was removed, followed by stirring at room temperature for 5 hours to perform sulfonation. The dropping funnel was removed, and the mixture was heated to 100 ° C. using an oil bath under a nitrogen stream to distill off methylene chloride and unreacted sulfuric anhydride.
After allowing to cool, 160 g of ethanol was added dropwise at room temperature over 3 hours, followed by refluxing for 2 hours while bubbling with nitrogen to carry out an ethoxylation reaction while removing generated hydrogen chloride. 237.7 g of an ethanol solution of ethoxysilane containing a phenylsulfonic acid group containing the obtained impurities was used for preparing a sol-gel of an organic polymer siloxane catalyst having the following hydrocarbon group containing a sulfonic acid group and a hydrocarbon group containing a mercapto group. Used as a raw material for the acid component.

(B) Preparation of an organic polymer siloxane having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group The above-mentioned sulfonic acid group-containing ethoxysilane was placed in a two-necked 500 ml round bottom flask equipped with a stir bar. 26.0 g of ethanol solution and 35.5 g of tetraethoxysilane (1
70.7 mmol), 6.7 g (34.3 mmol) of mercaptopropyltrimethoxysilane, ethanol 30
ml and mixed. 7.5 g of water (0.42 m
ol) was added dropwise over 30 minutes. Then heat this,
Stirred at 65 ° C. for 4 hours. After cooling, an aqueous solution obtained by mixing 15 ml of 28% aqueous ammonia and 75 ml of water was added dropwise, and the mixture was stirred at room temperature for 4 hours. The mixture was further stirred at 65 ° C. for 3 days and aged. This was distilled off under reduced pressure using an evaporator to obtain a white solid. Then, 200 ml of 2N hydrochloric acid was added, and the mixture was stirred at room temperature for 30 minutes. After filtration, the operation of washing with 500 ml of ion-exchanged water was repeated 10 times to remove hydrochloric acid. Finally, it was dried at 100 ° C. under reduced pressure for 6 hours. Through the above operations, 30 g of an organic polymer siloxane having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group was obtained.
When the solid acid content of the catalyst was measured, it was 1.0 meq / g
Met.

[Synthesis reaction of bisphenol A] Commercially available industrial phenol was placed in a 50-liter stainless steel
C., and left for 20 hours while introducing nitrogen from an annular nozzle provided in the lower part of the container. This phenol is converted to a sulfonic acid type ion exchange resin (K1221 manufactured by Bayer AG).
In a cylindrical reactor with an inner diameter of 50 mm filled with 500 ml,
The mixture was continuously supplied at a contact time of 30 minutes with the ion exchange resin, and the treatment was performed at 70 ° C. Further, the obtained phenol was subjected to a pressure of 40 mmHg,
Distillation was performed continuously at 0 ° C. to obtain purified phenol. The purified phenol obtained was replaced with nitrogen and the oxygen concentration was 1
Sent to a 50 l stainless steel container,
Stored at 50 ° C. 38.0 g / h of this purified phenol
And 2.3 g / h of acetone in a reactor filled with 30 ml of an organic polymer siloxane catalyst having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group prepared as described above as a bisphenol A synthesis catalyst. , And a synthesis reaction of bisphenol A was carried out at 75 ° C. In addition, a plunger pump is used to send phenol from each stainless steel phenol storage container, and each device is connected with stainless steel piping. The reaction was performed without contact between phenol and oxygen.

As a result, the conversion of acetone after 24 hours from the start of the reaction was 95.3%, and the selectivity for bisphenol A was 96.
2%. The reaction mixture flowing out of the reactor was
An adduct of bisphenol A and phenol was crystallized in a crystallizer at ℃, and separated into an adduct and a filtrate by a centrifuge. On the other hand, the operation was continued for 500 hours while circulating 90% of the filtrate to the reactor until the reaction solution reached a steady state. 500
After the analysis, the acetone conversion was 93 to 93 hours.
95%, bisphenol A selectivity was 95-98%. The total selectivity of impurities such as o, p'-bisphenol, indans, chromans, and trisphenols is 2 to 2.
5%.

[Purification of bisphenol A] An adduct of bisphenol A and phenol obtained from the crystallization / separator in a stable state was washed with phenol to obtain crystals having the following composition.

Crystal composition p, p'-bisphenol 67.9% by weight Phenol 31.9% by weight o, p'-bisphenol 880 ppm Other organic components 1290 ppm Other organic components are the sum of indans, chromans and trisphenols Is shown.

To this adduct, phenol is added,
Bisphenol A is adjusted to 50%, temperature 1
It was kept at 20 ° C.

This bisphenol solution was introduced into a falling film type crystallizer of a Sulzer type, and crystallization, sweating and melting were performed.
A purified adduct was obtained. Finally, phenol was distilled off from this adduct by distillation to obtain high-purity bisphenol A shown below.

Crystal composition p, p'-bisphenol 99.96% by weight Phenol 50 ppm o, p'-bisphenol 150 ppm Other organic components 240 ppm Further, as a result of performing a melt color test on the crystals, the color tone was less than APHA5. there were.

Comparative Example 1 [Synthesis reaction of bisphenol A] Example 1 was repeated except that 30 ml of Bayer K1221 in which 15% of the sulfonic acid groups were uniformly modified with cysteamine was used.
The reaction was carried out in the same manner as described above. As a result, the conversion of acetone 24 hours after the start of the reaction was 83.7%, and the selectivity for bisphenol A was 94.3%. The reaction mixture flowing out of the reactor was crystallized into an adduct of bisphenol A and phenol in a crystallizer at 45 ° C., and separated into a filtrate and an adduct by a centrifuge. 90% of the filtrate
While the reaction solution is circulating in the reactor until the reaction solution reaches a steady state.
The operation was continued for 00 hours. After 500 hours, the analysis showed that the conversion of acetone was 78 to 81% and the selectivity of bisphenol A was 92 to 94%. The total selectivity for impurities such as o, p'-bisphenol, indans, chromans, and trisphenols was 6 to 8%.

[Purification of Bisphenol A] An adduct of bisphenol A and phenol obtained from the crystallization / separator in a stable state was washed with phenol to obtain crystals having the following composition.

Crystal composition p, p'-bisphenol 67.8% by weight Phenol 31.9% by weight o, p'-bisphenol 1360ppm Other organic components 1840ppm Other organic components are the sum of indans, chromans and trisphenols. .

To this adduct, phenol was added,
Bisphenol A is adjusted to 50%, temperature 1
It was kept at 20 ° C.

This bisphenol solution was introduced into a Sulzer type falling film crystallizer, and crystallization, sweating,
By a melting operation, a purified adduct body was obtained. Finally, phenol was distilled off from the adduct by distillation in the same manner as in Example 1 to obtain bisphenol A having the purity shown below.
I got

Crystal composition p, p'-bisphenol 99.87% by weight Phenol 50 ppm o, p'-bisphenol 450 ppm Other organic components 760 ppm Further, as a result of a melt color test of this crystal, the color tone was APHA30. Was.

As described above, Example 1 using the organic polymer siloxane catalyst having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group was compared with Comparative Example 1 using a conventional ion exchange resin catalyst. Both the productivity, conversion and selectivity of bisphenol A are high, and high purity bisphenol A can be produced in high yield by fractional melt crystallization as compared with a conventional production method using an ion exchange resin catalyst.

It has also been found that as a polycarbonate raw material, which is a main use of bisphenol A, a colorless product with much less heat denaturation than before can be provided.

[0047]

According to the method of the present invention, there is provided a method for producing bisphenol A from phenol and acetone in the presence of an organic high molecular siloxane catalyst having a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group. By purifying the adduct after crystallization separation by fractional melt crystallization, bisphenol A of high purity with little heat denaturation and no coloring can be produced economically and advantageously.

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Claims (2)

[Claims] A bisphenol A is produced by reacting acetone and phenol in the presence of an organic high molecular siloxane having both a sulfonic acid group-containing hydrocarbon group and a mercapto group-containing hydrocarbon group, and then forming the resulting reaction mixture. Was cooled to generate adduct crystals of bisphenol A and phenol. After separating the adduct crystals from the slurry, impurities were removed by fractional melt crystallization to obtain purified adduct crystals, which were further obtained. A method for producing bisphenol A, comprising removing phenol from a purified adduct crystal to obtain high-purity bisphenol A. 2. The method according to claim 1, wherein the phenol solution of bisphenol A fractionated in the fractional melt crystallization is circulated to a reaction step of acetone and phenol or a fractional melt crystallization step.