JPS643176B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention produces high-quality 2,2-bis(4-hydroxyphenyl)propane (hereinafter abbreviated as p,p'-BPA) by reacting phenol and acetone in the presence of a hydrochloric acid-containing catalyst. Relating to a method of manufacturing. More specifically, high quality p,p′-
This invention relates to a method for producing BPA in high yield and economically. p,p'-BPA has been conventionally used as a raw material for polycarbonate or epoxy resin. As the uses and demand for these resins expand, high-quality resins are required, and as a result, high-quality resins with high purity and good color are required for p, p'-BPA, which is the raw material for these resins. products are now in demand. In particular, the p,p'-BPA used as a raw material for polycarbonate must be of high quality.
p′-BPA is required. Moreover, it is also required to economically produce such high quality p,p'-BPA. p that satisfies these requirements,
In order to produce p'-BPA, the raw materials phenol and acetone must be reacted at a high conversion rate in one contact, and p,p'-BPA is selectively produced with respect to the reacted raw materials. It is necessary to purify the p,p'-BPA produced by an easy method, and it is also necessary that the p,p'-BPA finally obtained is of high quality and in high yield. It is also required to be available and at low cost. More specifically, when the raw materials phenol and acetone are reacted in the presence of an acidic catalyst, in addition to the target p,p'-BPA, 2-(2-hydroxyphenyl)-2-(4- hydroxyphenyl)
Propane (hereinafter abbreviated as o,p′-BPA),
Isomeric by-products such as 2,2-bis(2-hydroxyphenyl)propane (hereinafter abbreviated as o,o'-BPA); 4-(4-hydroxyphenyl)-
2,2,4-trimethylchroman (hereinafter abbreviated as codimer), 2,4-bis(α,α-dimethyl-4-hydroxybenzyl)phenol (hereinafter abbreviated as BPX), 2-( 2-hydroxyphenyl)-2,4,4-trimethylchroman (hereinafter abbreviated as o-dimer), 5-hydroxy-
3-(4-hydroxyphenyl)-1,1,3-
Trimethylindane (hereinafter abbreviated as IPEP cyclic dimer), 2,4-bis(4-hydroxyphenyl)-4-methyl-1-pentene (hereinafter referred to as
High-boiling point by-products such as IPEP linear dimer (abbreviated as IPEP linear dimer); colored by-products of unknown structure are produced, and among these by-products, by-products that can be transferred to p,p'-BPA are Therefore, it is required to adopt a method for converting easily and efficiently. Conventionally, many methods have been proposed and are known for producing p,p'-BPA by reacting phenol and acetone in the presence of an acidic catalyst. For example, a method of reacting phenol and acetone using hydrogen chloride or hydrochloric acid as a catalyst, and a method of purifying and separating p,p'-BPA from the reaction mixture after the reaction is described in Publication No. 27-5367, Special Publication No. 36-
Publication No. 23335, Special Publication No. 38-4875, Special Publication No. 1977
-7186 Publication, Special Publication No. 6333, Special Publication No. 1973
−3379 Publication, Special Publication No. 47-10384, Special Publication No. 10384, Special Publication No. 10384
50-12428, JP 48-97853, JP 49-93347, JP 49-82651, JP 53-101347, JP 54-98748 ,
It has been proposed in Japanese Patent Application Laid-Open No. 54-98749 and others. Even if the reaction is carried out by the method described in any of these known documents to produce p,p′-BPA,
A large amount of by-products such as the isomer by-products, high-boiling by-products, and colored by-products are produced, and these by-products reduce the selectivity to the target p, p'-BPA,
Furthermore, since it contaminates the target product, lowering its quality, and making it difficult to purify, high-quality p,p'-BPA that meets the above requirements can be produced selectively and economically in high yield. I can't. Also,
Even if the reaction mixture obtained in the catalytic reaction is treated and purified by any of the methods described in the prior art documents, it is difficult to remove the by-products, and similarly high-quality p, p′- BPA cannot be produced selectively in high yield and economically. For example, among the prior art documents mentioned above that describe the reaction using hydrogen chloride or hydrochloric acid as a catalyst,
Publication No. 42-6333 discloses that p,p'-BPA is separated from the reaction mixture of phenol and acetone, and then p,p'-BPA is separated from the by-product (resinous by-product).
In order to recover BPA and improve the substantial selectivity and yield to p,p'-BPA, the by-product and phenol are treated in the presence of a catalyst consisting of hydrogen chloride or hydrochloric acid, and the reaction mixture is From p, p′-BPA
A method has been proposed to recover the However, by adopting this method, p, p'-BPA is separated from the reaction mixture obtained by reacting phenol and acetone in the presence of hydrogen chloride or hydrochloric acid, and the resulting by-products are described in the above publication. When the by-product treatment reaction and the condensation reaction of acetone and phenol are performed in separate reactors according to the method described above,
In addition to the complexity of the reaction system, the amount of byproducts processed in the byproduct isomerization reaction system increases significantly, and the byproduct isomerization reaction in this process reaches an equilibrium composition. p, p′ of living things
The isomerization efficiency to BPA is low. Therefore, the final selectivity to p,p'-BPA and its yield are low, and p,p'-BPA cannot be produced economically. Furthermore, among the above-mentioned prior art documents that describe the reaction using hydrogen chloride or hydrochloric acid as a catalyst, Japanese Patent Publication No. 42-26787 discloses that hydrogen chloride is removed from the reaction mixture after the reaction is completed. As a method for obtaining high purity p,p′-BPA from this mixture,
p, from the mixture from which hydrogen chloride gas has been removed by treating the reaction mixture under reduced pressure without applying heat or by blowing in a non-reactive gas.
p′-phenol adduct of BPA (hereinafter referred to as p, p′-
Abbreviated as BPA/PhOH. ) is crystallized, and the p,
By decomposing p′-BPA・PhOH, p,
A method for recovering p′-BPA has been proposed. In this embodiment, it is described that the reaction mother liquor obtained by separating the p,p'-BPA/PhOH can be recycled and reused in the reactor. However, even if the reaction is carried out according to this method and the reaction mixture is treated in the same way, in order to efficiently remove hydrogen chloride,
It is necessary to suppress the formation of hydrochloric acid within the reaction system,
For this purpose, as is clear from the examples in the same publication, it is necessary to reduce the amount of water produced by the reaction, so the reaction must be carried out while maintaining the rate of change of acetone at a low level of about 50% or less. Even if the mother liquor is recycled and reused, hydrogen chloride gas has already been removed, making it difficult to reuse hydrogen chloride effectively, making it impossible to economically obtain high-purity p,p'-BPA. There are drawbacks. In addition, in a comparative experiment in Example 1 of the same publication, p, p'-
A method for separating BPA has been disclosed, but this method has the drawbacks that p,p'-BPA is of poor quality and hydrogen chloride, which is a catalyst, cannot be recycled and reused. In addition, there is a method in which phenol and acetone are reacted using an acidic ion exchange resin or a modified product thereof as a catalyst, and p, p'-BPA is purified and separated from the reaction mixture after the reaction by the above method. Regarding the method, Japanese Patent Publication No. 36-23334,
Special Publication No. 37-14721, Publication No. 37-981,
Special Publication No. 41-4454, Publication No. 10337-1970,
JP-A-46-19953, JP-A-48-71389, JP-A-49-48319, JP-A-52-42861, JP-A-54-19951, JP-A-54-19952
There are many proposals such as No. 1 Publication and others. In order to carry out the reaction using these proposed methods and fully demonstrate the catalytic activity, it is necessary to
It is necessary that the concentration of PhOH is kept low so that it does not crystallize out and form a slurry reaction mixture, and that the reaction mixture is a homogeneous solution. For this purpose, it is necessary to keep the conversion rate of the raw material acetone low to 55 mol% or less, or to increase the molar ratio of phenol to acetone. Therefore, in all of these proposals, the rate of change of raw materials per contact is low, and a large amount of unreacted raw materials must be recovered from the reaction mixture and further recycled to the reaction system. However, there is a drawback that a large amount of utility costs are required to recover and recycle the raw materials, and the reaction cannot be carried out efficiently or economically. In addition, in reactions using these acidic ion exchange resins, in addition to p, p'-BPA, similar isomer by-products, high-boiling point by-products, and coloring are produced, as in the case of using hydrogen chloride or hydrochloric acid. More sexual byproducts are produced. Furthermore, in the method of reacting using an acidic ion exchange resin as a catalyst, these by-products are
By isomerizing to p′-BPA, the p, p′-
Various attempts have been proposed to improve the yield of BPA. For example, for this purpose, unreacted starting materials and p,p'-BPA or p,
A method of recovering p'-BPA/PhOH and recycling the remaining by-products together with phenol and acetone to the reactor containing the acidic ion exchange resin was proposed in 1973.
This is proposed in Publication No. 981. In addition, the bulletin states:
A reaction containing the above-mentioned by-products obtained by crystallizing p,p'-BPA/PhOH by cooling the product mixture obtained by distilling off unreacted raw materials from the reaction mixture and separating the crystals. Embodiments are also included in which the mother liquor is recycled to the reactor as well.
However, according to the method proposed in the publication,
Even if continuous reactions are carried out by circulating the reaction mother liquor containing by-products into the reactor, it is not only impossible to eliminate the disadvantages of using acidic ion exchange resins as catalysts, but also other problems. Because the rate of isomerization of the by-products to p, p'-BPA in the reaction mother liquor is low, the by-products accumulate in the reaction system, which not only impairs the smooth progress of the reaction but also reduces the quality of the product. The disadvantage is that p,p'-BPA of 100% cannot be obtained. Furthermore, if the reaction is carried out continuously for a long period of time, this tendency becomes even more pronounced, and the activity of the acidic ion exchange resin catalyst decreases significantly. It can hardly be called an advantageous method. The present invention has been made in view of the current state of the prior art in the technical field of producing p,p'-BPA, and its purpose is to combine phenol and acetone in the presence of an acidic catalyst consisting of a hydrochloric acid-containing catalyst. To provide a rational process for selectively producing high quality p,p'-BPA in high yield and economically in a method for producing p,p'-BPA by reacting with p,p'-BPA. That's true. More specifically, a slurry reaction mixture produced by reacting phenol and acetone in the presence of hydrochloric acid is separated into p,p′-BPA・PhOH and a reaction mother liquor, and the reaction mother liquor is subjected to a reaction. This is based on the discovery that the above object can be achieved by circulating the p,p'-BPA/PhOH in the system and subjecting it to a specific treatment. To summarize the present invention, the present invention provides a method for producing p,p'-BPA by reacting phenol and acetone in the presence of a hydrochloric acid-containing catalyst in a continuous process, including: (A) supplementing phenol to the reactor; The reaction is carried out by continuously charging circulating phenol, supplementary acetone, supplementary hydrogen chloride or hydrochloric acid, the circulating oil phase mother liquor described later, and the circulating water phase mother liquor described later, and crude p,p'-BPA is produced as a reaction mixture in the reaction system.・A step of forming a slurry reaction mixture consisting of PhOH crystals and a two-liquid phase reaction mother liquor consisting of an oil phase mother liquor and an aqueous phase mother liquor, (B) extracting the slurry reaction mixture from the reactor and converting it into crude p,p ′--BPA/PhOH and the two-liquid phase reaction mother liquor; (C) separating the two-liquid phase reaction mother liquor obtained in step (B) into an oil phase mother liquor and an aqueous phase mother liquor; A step of circulating the oil phase mother liquor as a circulating oil phase mother liquor to the reactor, and extracting a portion of the aqueous phase mother liquor and circulating the remainder as a circulating water phase mother liquor to the reactor, (D) a step obtained in the above step (B). Crude p,p′-BPA・PhOH is dissolved in phenol solvent, and the crude p,p′-
After neutralizing hydrogen chloride or hydrochloric acid contained in BPA/PhOH with a base, p,p′-BPA/PhOH is crystallized and purified by separating it.
Step of obtaining p'-BPA/PhOH, (E) Purified p,p'-BPA/PhOH obtained in the above step (D)
By heating phenol and p, p'-
(F) recovering phenol and p,p′-BPA from the thermal decomposition products of step (E); and (G) recycling the phenol recovered in step (F). a step of recycling the phenol into the reactor of the step (A) or the neutralization purification step (D) as the phenol solvent;
This is a method for producing p′-BPA. According to the method of the present invention, phenol and acetone are reacted in a continuous process in the presence of a hydrochloric acid-containing catalyst, and from the resulting slurry reaction mixture, crude p.
The crystals of p'-BPA/PhOH are separated, the reaction mother liquor containing most of the by-products and hydrochloric acid-containing catalyst is recycled and reused in the reactor, and the crude p, p'-BPA/PhOH crystals are neutralized and purified. Purified p,p′-BPA・
By obtaining PhOH and decomposing it, there is an advantage that high quality p,p'-BPA can be obtained selectively and in high yield. Furthermore, the hydrochloric acid-containing catalyst in the reaction mother liquor can be effectively recycled without adding any distillation operation, and p, p′-
It has the advantage that BPA can be effectively recovered, and it is also more rational than any other conventional manufacturing process, producing high quality p, p'-- at low cost.
It has the advantage of being able to produce BPA. In the method of the present invention, the acidic catalyst in the condensation reaction of phenol and acetone is a hydrochloric acid-containing catalyst, and usually supersaturated hydrogen chloride is present, and hydrochloric acid and hydrogen chloride are often present in the reaction system. In the method of the present invention, as the acidic catalyst, the above-mentioned hydrochloric acid or a catalyst consisting of the above-mentioned hydrochloric acid and hydrogen chloride alone can be used, but hydrochloric acid and other co-catalyst components can also be used in combination. As this co-catalyst component, conventionally known ones are used. Usually a sulfur-containing compound that is soluble in the reaction mixture is used, and either gaseous, liquid or solid sulfur compounds can be used. Specifically, these promoters include inorganic sulfur compounds such as sulfur monochloride, sulfur dichloride, sodium thiosulfate, potassium thiosulfate, and hydrogen sulfide; methyl mercaptan, ethyl mercaptan,
Alkyl mercaptans such as n-propyl mercaptan and n-butyl mercaptan; thiophenols such as thiophenol, p-methylthiophenol, p-ethylthiophenol, p-chlorothiophenol, thiohydroquinone, and thionaphthol; thioglycolic acid, Mercapto-substituted aliphatic carboxylic acids such as thioacetic acid and thiopropionic acid; alkali metal salts of the alkyl mercaptans, thiophenols, and mercapto-substituted aliphatic carboxylic acids; mercaptals and mercaptols derived from the mercaptans, etc. can be exemplified. When these sulfur compounds are used as cocatalysts, the molar ratio to HCl in the reaction system is usually in the range of 1/2000 to 1/30. In the reaction step (A) of the method of the present invention, raw materials are supplied to the reactor from supplementary phenol to replenish the phenol consumed in the reaction or extraction, and from the decomposition step (E) of purified p, p'-BPA/PhOH described later. Recovered circulating phenol, replenishing hydrogen chloride or hydrochloric acid to replenish hydrogen chloride or hydrochloric acid extracted or otherwise consumed in the reaction system, and circulating aqueous phase mother liquor sent from the mother liquor circulation step (C) described later are continuously is loaded into the At that time, the molar ratio of total phenol to total acetone supplied to the reactor is usually 4 to 4.
It should be in the range of 5 to 10 in order to maintain the reaction system as a slurry system, to allow the reaction to proceed smoothly, to smoothly stir the slurry reaction mixture, and to ensure sufficient contact with oil and water. is preferred. In addition, the amount of hydrogen chloride and hydrochloric acid in the reaction system as HCl is supplied at a ratio that is usually in the range of 0.5 to 5 moles based on the number of moles of total HCl contained in 1000 g of the reaction mixture in the reactor, and furthermore, the condensation reaction In order to smoothly proceed with the conversion reaction of the by-products to p, p'-BPA and to suppress the accumulation of the by-products in the reaction system, it is preferable to supply the by-products at a ratio of 1 to 5 moles. . Each of the above-mentioned raw materials to be supplied to the reactor is continuously supplied to the reactor. Here, continuous supply refers to a method in which each raw material in the reactor is supplied as a pulsating flow within a range that maintains the above range. It is also possible to adopt an intermittent supply method. Further, as a reactor for carrying out the reaction of the present invention, a single tank reactor or a multi-tank reactor can be used. In the method of the present invention, the reaction step (A) involves a condensation reaction between phenol and acetone, a conversion reaction of by-products in the circulating mother liquor to p, p'-BPA, and p, p'-BPA and p, p'-BPA produced in the condensation reaction. A PhOH formation reaction takes place. In the condensation reaction of phenol and acetone,
In addition to p,p'-BPA, the aforementioned isomeric by-products, small amounts of high-boiling by-products, and trace amounts of colored by-products are produced. In addition, p, p'-BPA is generated not only from the isomer by-products contained in the circulating reaction mother liquor [the circulating oil phase mother liquor and the circulating water phase mother liquor, especially the circulating oil phase mother liquor] but also from the high boiling point by-products. . At that time, when the condensation reaction and the conversion reaction are carried out while circulating the reaction mother liquor containing the by-products into the reaction system, p,
p,p′-BPA is
When carried out under heterogeneous reaction conditions in which a slurry reaction mixture is formed that crystallizes as BPA/PhOH crystals and the reaction mother liquor forms two liquid phases, p,p'-BPA/PhOH separated from the reaction mixture is It has the advantage that the content of any by-product components contained is reduced, and the conversion rate of said by-products to p,p'-BPA in the reaction system is extremely high. That is, since the by-product is difficult to form an adduct with phenol,
Most of it is dissolved in the oil phase in the slurry reaction mixture, and the isomerization and conversion reactions proceed to equilibrium concentrations, and the generated p,p'-BPA forms adducts with phenol and crystallizes. As a result, the isomerization reaction and conversion reaction proceed selectively, and the target product p,p′-BPA
The yield is substantially improved. Therefore, in the method of the present invention, the reaction mixture contains crude p,p'-BPA.
It is necessary to form a slurry reaction mixture in which PhOH crystallizes, and the reaction mother liquor constituting it must be a two-liquid phase mother liquor consisting of an oil phase mother liquor and an aqueous phase mother liquor. . In order to form such a slurry reaction mixture, the conditions for supplying raw materials to the reactor in the reaction step (A) are set as described above, and the rate of change of acetone is usually set as follows. . That is, during the condensation reaction, the reaction is carried out until the conversion rate of acetone reaches 90% or more, forming a slurry reaction mixture with better properties and producing high quality p,p'-BPA from this mixture. In order to selectively obtain a high yield, it is preferable to carry out the reaction until the conversion rate of acetone reaches 95% or more. Furthermore, the temperature during the reaction is usually 25 to 70°C, preferably 30 to 60°C.
is within the range of In the method of the present invention, in the slurry reaction mixture separation step (B), the slurry reaction mixture produced in the reactor is discharged from the reactor. The discharged slurry reaction mixture is purified by conventional means such as filtration, centrifugation, hydrocyclone, separation, etc.
It is separated into p'-BPA/PhOH crystals and the two-liquid phase mother liquor. Here, the crude p obtained in this separation step,
The crystal of p′-BPA・PhOH is p,p′-BPA・
The main component is PhOH, but it also contains isomer by-products such as o,p'-BPA, o,o'-BPA, codimer, BPX, o-dimer, isopropenylphenol. dimer, IPEP cyclic dimer,
It contains small amounts of by-products such as high-boiling point by-products such as IPEP linear dimer and colored by-products of unknown structure, as well as trace amounts of hydrochloric acid. Said rough p, p'-
The above-mentioned by-products contained in BPA/PhOH can be further reduced by washing with phenol, hydrous phenol, hydrochloric acid, or the like. In the method of the present invention, the two-liquid phase reaction mother liquor obtained in the separation step (B) is further separated into an oil phase mother liquor and an aqueous phase mother liquor in a mother liquor circulation step (C). Here, the separated oil phase mother liquor contains the raw material phenol used in excess and recovered unreacted, unreacted acetone, p, p'-BPA dissolved in the phenol, the isomer by-product, and the high It contains by-products such as boiling-point by-products and colored by-products, hydrochloric acid in an allowable amount for dissolution, and a sulfur compound used as a co-catalyst. The aqueous phase mother liquor contains most of the hydrochloric acid recovered from the reactor, unreacted acetone, a trace amount of p, p'-BPA, a trace amount of the isomer by-product, and raw materials used in excess and recovered unreacted. Contains phenols. Here, the separated oil phase mother liquor is circulated to the reactor as a circulating oil phase mother liquor. In that case, the entire amount of the oil phase mother liquor can be circulated as a circulating oil phase mother liquor, but when performing a long-term continuous reaction, in order to avoid the accumulation of the colored by-products in the reaction system, If necessary, a portion of the oil phase mother liquor, for example, usually 2 to 30% by weight, preferably 5 to 15% by weight, is extracted and the remainder is preferably recycled to the reaction system.
The above-mentioned portion of the extracted oil phase mother liquor is treated by any method, but usually the extracted oil phase mother liquor is chlorinated by blowing inert gas or distilling under reduced pressure. After hydrogen is recovered or neutralized by the action of an alkali, it can be treated by any of the following methods.
Note that the recovered hydrogen chloride can also be reused as supplementary hydrogen chloride in the reactor of the reaction step (A). [1] After removing most of the phenol from the extracted oil phase mother liquor by distillation etc., the can residue is cracked and separated into distilled p-isopropenylphenol and tar, and the tar is removed. will be discarded. The recovered p-isopropenylphenol undergoes an addition reaction (addition reaction step) with phenol in the presence of hydrochloric acid to form p, p′-
BPA/PhOH crystals crystallize. The p,p′-BPA・PhOH obtained by separating this is the crude p obtained in the separation step (B) of the slurry reaction mixture,
In addition to p′-BPA/PhOH, process together, or
Or it can be treated similarly. On the other hand, the separated mother liquor can be treated in the same manner as the extracted mother liquor and recycled and reused in the addition reaction step. [2] Part of the phenol is distilled off and concentrated from the extracted oil phase mother liquor by distillation or the like, and p, p'-
Crystallize BPA/PhOH. The p,p'-BPA/PhOH obtained by separating this is treated in the same manner as in [1] above. On the other hand, the separated mother liquor may be discarded or subjected to cracking treatment and addition reaction in the same manner as in [1] above. [3] After recovering most of the phenol from the extracted oil phase mother liquor by distillation or the like, the can residue is cracked to separate the distilled p-isopropenylphenol and a tar component, and the tar component is discarded. The recovered p-isopropenylphenol undergoes an addition reaction with phenol in the presence of hydrochloric acid (addition reaction step) to crystallize p,p'-BPA/PhOH crystals, and the slurry addition mixture is transferred to the reaction step (A). into a reactor or separate process
It can also be mixed with the slurry reaction mixture discharged from the reactor (B) and treated together. [4] The cracking distillate in [1], [2] and [3] above may be directly returned to the condensation reaction step and converted into p,p'-BPA. In addition, the aqueous phase mother liquor separated in the mother liquor circulation step (C) contains water generated by the condensation reaction, and if the entire amount is circulated, water will accumulate in the reaction system. The remainder after a portion is withdrawn is recycled to the reactor as a circulating aqueous phase mother liquor. In this case, the weight ratio of the circulating aqueous phase mother liquor to the circulating oil phase mother liquor to the reactor in the reaction step (A) is preferably maintained in the range of usually 0.01 to 2, preferably 0.03 to 1.2. The reaction rates of the polycondensation reaction and rearrangement reaction are maintained within an appropriate range, and p per unit volume of the reaction tank is
It is possible to maintain a large production amount of p'-BPA/PhOH, maintain the slurry concentration of the generated slurry reaction mixture within an appropriate range, and produce high-quality p, p'-BPA/PhOH with low by-product content. In order to economically produce , the weight ratio of the circulating aqueous phase mother liquor to the circulating oil phase mother liquor is preferably within the above range. Note that it is also possible to adopt a method of recovering hydrogen chloride or concentrated hydrochloric acid from the extracted aqueous phase mother liquor and effectively reusing it as hydrogen chloride or hydrochloric acid for replenishment to the reaction step (A). In the method of the present invention, crude p,p′-BPA・
In the PhOH neutralization and purification step (D), the crude p,p'-- obtained in the separation step (B) of the slurry reaction mixture is
Hydrogen chloride or hydrochloric acid contained in BPA/PhOH,
and the by-product impurities are removed. For this purpose, the crude p,p'-BPA·PhOH is dissolved in a phenolic solvent. Here, the proportion of the phenol solvent used is usually in the range of 0.1 to 10, preferably in the range of 0.5 to 5, as a weight ratio to the crude p,p'-BPA.PhOH. The temperature during the dissolution treatment may be room temperature, but it is preferable to dissolve it under heating.
Further, the phenol solvent used may be a phenol sole solvent, but it is preferable to use water-containing phenol. As the phenolic solvent, use of a hydrous phenol having a composition such that when the crude p,p'-BPA/PhOH is dissolved forms a two-liquid phase solution consisting of an oil phase solution and an aqueous phase solution, the neutralization operation can be carried out. becomes easier and the purification effect becomes greater. The content of phenol in this hydrous phenol is usually in the range of 10 to 65% by weight, preferably 20 to 60% by weight. Here, when the phenol solvent is a water-containing phenol and its water content is high, the water-containing phenol may form two liquid phases, an oil phase and an aqueous phase. When carrying out this dissolution treatment with hydrous phenol, it is also possible to adopt a method of first dissolving it in phenol and then adding water in a proportion that will form the hydrous phenol. During this dissolution process, if the solution forms two liquid phases, phenol, p, p'-BPA of the target product, and p, p'-
In order to suppress the loss of BPA/PhOH due to dissolution in the aqueous phase, sodium chloride, potassium chloride, sodium sulfate, potassium sulfate, magnesium sulfate,
It is also preferable to dissolve a neutral salt compound such as calcium chloride, ammonium chloride, magnesium chloride, etc. in the aqueous phase. By carrying out the above dissolution treatment, hydrogen chloride or hydrochloric acid contained in the crude p,p'-BPA·PhOH is dissolved in the solution. The crude p,
When the phenolic solvent solution of p'-BPA/PhOH is a homogeneous solution, both crude p, p'-BPA/PhOH and hydrogen chloride or hydrochloric acid are dissolved. In addition, if the crude p,p'-BPA/PhOH solution in phenolic solvent forms a two-liquid phase solution consisting of an oil phase solution and an aqueous phase solution, most of the hydrogen chloride or hydrochloric acid will be in the aqueous phase. extracted and a small remaining portion is dissolved in the oil phase solution, while most of the crude p, p′-
BPA/PhOH is dissolved in the oil phase solution. The hydrogen chloride or hydrochloric acid dissolved in the phenol solvent solution of the crude p,p'-BPA is neutralized with a base to remove the hydrogen chloride or hydrochloric acid. Here, the base can be added before dissolving the crude p,p'-BPA/PhOH, or it can be added after it is dissolved. In either case, the pH of the solution after neutralization is usually adjusted to a range of 2 to 5, preferably 3 to 4.5. If the phenol solvent solution of the crude p,p'-BPA/PhOH forms a two-liquid phase mixture as described above, a method is adopted in which a base is added to this two-liquid phase mixture to neutralize it at the same time. Alternatively, it is also possible to separate the two-liquid phase mixture into an oil phase solution and an aqueous phase solution and neutralize each solution by adding a base separately, but the latter method is adopted. It is preferable to do so. Here, the bases include sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogen carbonate,
Potassium hydrogen carbonate, sodium phosphate, magnesium phosphate, potassium phosphate, ammonia, ammonium hydroxide, disodium hydrogen phosphate, dipotassium hydrogen phosphate, dimagnesium hydrogen phosphate,
Aqueous solutions of basic compounds such as inorganic bases such as magnesium hydroxide and calcium hydroxide, and organic bases such as sodium phenolate, potassium phenolate, sodium methoxide, sodium ethoxide, and alkali metal salts of p,p′-BPA are used. Usually used. The crude p, p′- after neutralization treatment
By treating a solution of BPA/PhOH by conventional means such as cooling or concentrating, p,
p'-BPA/PhOH crystallizes. At that time, crude p,
If the p′-BPA/PhOH solution forms a two-liquid phase solution, the above-mentioned crystallization treatment can be performed on the two-liquid phase solution, or the two-liquid phase solution can be separated. Although the crystallization treatment can be carried out on the liquid oil phase solution, it is preferable to carry out the crystallization treatment by the latter method. By separating the p,p'-BPA/PhOH crystallized in this way,
The content of impurities such as the above-mentioned isomer by-products, high-boiling point by-products, and colored by-products is small, and highly purified p,p'-BPA/PhOH can be obtained. Although the p,p'-BPA/PhOH obtained in this manner is sufficiently pure as it is, it may be further subjected to purification operations such as washing or recrystallization as necessary. In the method of the present invention, purified p,p′-BPA・
In the PhOH decomposition step (E), the purified p,p′-BPA・
PhOH converts into phenol and p,p′-BPA by heating.
It is broken down into. This decomposition reaction is usually 100 to 200
This occurs by heating to a temperature in the range of 130 to 180°C. The pressure during this decomposition reaction varies depending on the decomposition temperature, but it is usually under reduced pressure conditions where the phenol produced by the reaction can be vaporized, and is generally 1 to 500 mmHg, preferably 5 to 300 mmHg. range. In the method of the present invention, in the recovery step (F), phenol and p,p'-BPA are recovered from the products obtained in the decomposition step (E), and are usually recovered from the can residue of the decomposition reaction. . The purified p,p'-
When the decomposition reaction of BPA/PhOH is carried out in a distillation column, distillation column, etc., phenol is recovered from the top of the column, and p,p'-BPA is recovered in a molten state from the bottom of the column. The recovered p,p'-BPA is of sufficiently high quality without any purification treatment, but if necessary, it may be washed with water, hot water, weakly acidic hot water, or other solvents, or further recycled. Purification treatments such as crystallization treatments can also be performed. In the method of the present invention, in the recovered phenol circulation step (G), the phenol recovered in the recovery step (F) is recycled as recycled phenol to the reactor of the reaction step (A), or (D) is recycled as the phenolic solvent. At this time, when the decomposition reaction is carried out under reduced pressure conditions, the phenol is usually recovered as a gas, and is recovered as a liquid by condensing it. Next, a schematic process chart for carrying out the method of the present invention will be explained with reference to the attached FIG. 1. A in FIG. 1 is an example of a continuous condensation reaction apparatus for carrying out the method of the present invention. The replenishment raw material tank 1, the replenishment raw material tank 2, the circulating oil phase mother liquor tank 3, and the circulating water phase mother liquor tank 4 are the first reaction tank 11 and the second reaction tank in the reaction step (A).
This is a device for continuously supplying raw materials to a serial multi-stage reactor consisting of a reaction tank 12 and a third reaction tank 13, and the reaction step (A) is performed in the serial multi-stage reactor.
A continuous condensation reaction is carried out to form a slurry reaction mixture, and the slurry reaction mixture is transferred to receiver 1.
Gather at 4. The slurry reaction mixture is transferred to the centrifuge 15 in the next separation step (B) to remove crude p,p'-BPA/PhOH.
and a two-liquid phase reaction mother liquor, and the two-liquid phase reaction mother liquor is further separated into an oil phase mother liquor and an aqueous phase mother liquor in an oil-water separator 16 in the next circulation step (C). After discharging a part of the separated oil phase mother liquor and aqueous phase mother liquor from 17 and 18, respectively, as necessary, the remaining mother liquors are transferred to the reaction step.
Recirculate and use in the reactor (A). When circulating the aqueous phase mother liquor, it was saturated or supersaturated with the supplied HCl gas 6 in the HCl absorption tank 5 and then circulated. The crude p,p'-BPA/PhOH separated from 30 in the centrifugal separator 15 is continuously supplied together with the phenol solvent to the dissolution tank 40 in the neutralization purification step (D) of the continuous neutralization crystallizer shown in Figure 1B. When dissolved, a two-liquid phase solution consisting of an oil phase solution and an aqueous phase solution is formed, and this is received in the tank 41 and stirred. The oil phase solution from the tank 41 and the alkaline aqueous solution from the tank 31 are continuously added to the neutralization tank 42 and mixed, and after adjusting the pH of the aqueous phase solution to a predetermined value, the oil and water are separated in the oil-water separation tank 43. To separate. A portion of the aqueous phase solution was removed from 33, and the remainder was circulated to dissolution tank 40. In addition, the oil phase solution and the new phenol from 32 are sent to a crystallization tank 44 to be crystallized to form a slurry mixture, which is separated in a centrifuge 46 and a cake of p,p'-BPA/PhOH is formed. and mother liquor. Furthermore, this p,p'-BPA/PhOH cake is washed with an aqueous phenol solution, and the washing liquid is mixed with the mother liquid, and then separated into a crystallized oil phase mother liquid and a crystallized water phase mother liquid in an oil-water separation tank 47. , a portion is discharged from 34 and 35 as necessary, and the remaining portion is circulated to crystallization tank 44 and dissolution tank 40, respectively. The separated purified p,p'-BPA/PhOH is continuously supplied to the melting tank 70 of the continuous thermal decomposition apparatus shown in FIG. It is supplied to the decomposition column 72 and decomposed into phenol and p, p'-BPA molten residue, the phenol is recovered from the top 62 of the column, and p, p'- from the bottom of the column.
Collect the BPA melt. In the recovered phenol circulation step (G), the recovered phenol is circulated as recycled phenol to the reaction tank of the reaction step (A), or
It is recycled as a phenol solvent to the neutralization and purification step (D). The molten p, p'-BPA residue obtained from the bottom of the cracking tower is mixed with hot water adjusted to be slightly acidic in the oil-water mixing tank 73 of the recovery step (F), and washed in the hot water washing tank 74. , after crystallization in the crystallization tank 75, the centrifugal separator 7
6, and dried in a vacuum dryer 77. From 80, purified p,p'-BPA crystals are obtained. Next, the method of the present invention will be specifically explained using examples. In addition, in Examples and Comparative Examples, the rate of change of acetone, the reaction mixture in the reaction system 1000
The amount of HCl contained in g and the weight ratio of the aqueous phase mother liquor to the oil phase mother liquor in the slurry reaction mixture in the reaction system were measured by the following methods. Also,
Crude p, p'-BPA/PhOH, p, p'-BPA contained in circulating oil phase mother liquor, circulating water phase mother liquor, phenol,
The compositions of water, HCl, and byproducts were determined by the following methods. Furthermore, the quality of purified p,p'-BPA was determined by the following method. 1. Method for quantifying unreacted acetone The acetone conversion rate was determined by dissolving the reaction mixture in an ethanol solvent, neutralizing it, and quantifying unreacted acetone using gas chromatography. 2. Determination of phenol and p,p'-BPA Phenol and p,p'-BPA were determined using gas chromatography. 3 HCl quantitative method After dissolving the sample in ethanol solvent, HCl is
It was quantified according to the usual neutralization titration method. 4 Method for quantifying by-products By-products were quantified by internal standard method using high-performance liquid chromatography after dissolving a sample in ethanol and neutralizing the sample. 5 Measurement of coloration degree of circulating oil phase mother liquor and crude p, p'-BPA/PhOH Place the sample in a volumetric flask and dilute with ethanol. Fill a 10 cm cylindrical glass cell with this diluted solution and use a Spectronic 70 spectrophotometer. [Baush &L'ombe]
Absorbance (or transmittance) at 360 nm and 480 nm was measured using a 360 nm and 480 nm probe manufactured by Romb Co., Ltd. The concentration of the sample used in the measurement was changed as appropriate depending on the degree of coloration of the sample. The degree of coloration of the sample was expressed using the following formula. E1% 1cm=A/cb...(1) ^* Here, A=absorbance c=concentration of sample (W/V%) b=cell length (light path length) (cm) In addition, the following examples and Written in the comparative example
E ₃₆₀ and E ₄₈₀ have a measurement wavelength of 360 nm, respectively.
Shows E1% 1cm at 480nm. Figure 2 shows the reaction time (hours) (horizontal axis) regarding the time-dependent changes in the degree of coloring of the circulating oil phase mother liquor and crude p,p'-BPA.PhOH in Example 1 of the present invention, which will be described later.
It is a graph showing the relationship between the degree of coloration (E1% 1 cm×10 ⁴ ) (vertical axis) at 480 nm. (*) Robert, M. Silverstein, G. Kratom,
“Spectral Identification Method of Organic Compounds” by G. Claytom. Bassler, translated by Jun Araki and Yoichiro Mashiko (Tokyo Kagaku Dojin) 6. Measurement of the weight ratio of water phase mother liquor to oil phase mother liquor in a slurry reaction mixture The slurry reaction mixture flowing out of the reaction tank is received in a storage tank maintained at the same temperature as the reaction tank. Once a certain amount of the reaction mixture has accumulated in the storage tank, it is charged into a centrifugal separator kept at the same temperature as the reaction tank.
Swirled until cake was almost dry. The mother liquor discharged from the centrifugal separator was led to a static tank, and oil and water were separated. Next, the volume and specific gravity of each phase were measured, and the weight ratio of the aqueous phase mother liquor to the oil phase mother liquor was determined. 7 Quality Assay Method for Purified p,p'-BPA (1) Melt Color Melt color was determined by melting the sample at 250°C and immediately comparing it with Hazen standard solution. (2) Freezing point A sample and an immersion wire thermometer (ASTM102) were placed in a measuring tube, cooled in a constant temperature bath at 140°C, and measured according to the usual method. (3) Analysis of organic impurities Analysis was performed using the same high performance liquid chromatography as in 4 above. (4) Measurement of coloration degree E ₃₆₀ and E ₄₈₀ Dilute the sample with ethanol to 20W/V%,
The absorbance (transmittance) was determined in the same manner as in 5 above. Example 1 (1) A continuous reaction was carried out using the reaction apparatus shown in FIG. The temperature of the first reaction tank, second reaction tank, and third reaction tank was maintained at 50°C, and the temperature of the centrifugal separator and oil-water separation tank was maintained at 50°C. The first reaction tank was supplemented with acetone 24.6g/hr, phenol supplemented with 143g/hr,
15% methyl mercaptan sodium aqueous solution 1.0
g/hr, circulating oil phase mother liquor 269 g/hr, circulating water phase mother liquor 128 g/hr, and supplementary HCl gas 5/hr. The slurry reaction mixture flowing out from the third reaction tank was intermittently charged into a centrifugal separator for solid-liquid separation. The obtained centrifuged cake was subjected to the neutralization and purification experiment described later, and the oil phase mother liquor and aqueous phase mother liquor in excess of the predetermined supply amount were extracted from the system, and the remainder was circulated to the reaction tank and reused. Table 1 shows the compositions and reaction conditions of the circulating oil phase mother liquor and circulating water phase mother liquor in this continuous reaction.

【table】

[Table] As a result of continuing this experiment for 350 hours,
Indicates the degree of coloration of the oil phase mother liquor and centrifuged cake.
The E ₄₈₀ value is determined by the reaction time of 300 as shown in Figure 2.
It can be seen that the reaction time increases over time, and shows a tendency to increase as the mother liquor is repeatedly used in circulation, but when the reaction time exceeds 300 hours, it reaches a plateau and does not increase any further. Similarly, oil phase mother liquor and centrifuged cake (crude p, p′-
The concentration of by-products contained in BPA/PhOH) also stabilized at a constant value. At this time, by-products, HCl and
The H ₂ O concentrations were as shown in Table 2.

[Table] Also, the acetone conversion rate during this reaction is 99
%, acetone reference p, p′- over 350 hours
The total yield of BPA was 99.5 mol%. (2) On the other hand, crude p, p′- obtained by continuous condensation reaction
BPA/PhOH was continuously neutralized and crystallized as follows.
500g/hr of the p,p'-BPA/PhOH was charged into a dissolution tank kept at 70°C, and 1000g/hr of the circulating water phase of the neutralization system described later and 320g/hr of the mother liquor of the crystallized oil phase described later were added.
hr and stirred thoroughly. Said p, p'-
A two-liquid phase solution consisting of an oil phase solution and an aqueous phase solution in which BPA/PhOH was completely dissolved was supplied to the neutralization tank. In the neutralization tank, 37 ml/hr of 18% NaOH aqueous solution was continuously flowed to adjust the pH value of the aqueous phase after neutralization to 4 (weakly acidic). The neutralized product was then sent to an oil-water separation tank and separated into an oil phase and an aqueous phase. The separated aqueous phase was reused as the circulating aqueous phase of the neutralization system. At this time, since the amount of the circulating aqueous phase to be reused was 1000 g/hr as described above, the remaining aqueous phase was discharged from the neutralization system as waste water. On the other hand, the oil phase, new phenol, and the crystallization mother liquid oil phase that came out of the oil-water separation tank were continuously injected and mixed into the crystallization tank, and the molar ratio of p, p'-BPA and phenol in the crystallization tank was set to 2.5. I adjusted it so that
Further, the crystallization mother liquid aqueous phase described later was continuously supplied to the crystallization tank from the other supply port. Continuous crystallization was performed in a heated crystallization tank, and the resulting slurry mixture was collected in a receiver, and solid-liquid separation was performed using a heated centrifuge once every 30 minutes.
The separated p,p′-BPA/PhOH is further sprinkled with a phenol aqueous solution to rinse the cake.
Purified p,p′-BPA・PhOH237g (every 30 minutes)
I got it. On the other hand, the crystallization mother liquor and washing liquid produced by the solid-liquid separation of the slurry mixture are collected in an oil-water separation tank, separated into an oil phase and an aqueous phase, and recycled as the crystallization oil phase mother liquor and the crystallization water phase mother liquor. Reused. The purified p,p′-BPA・PhOH produced here
The quality is shown in Table 3.

【table】

[Table] (3) Next, removal of phenol from the purified p,p'-BPA/PhOH and production of p,p'-BPA/PhOH were performed as follows. First, purified p, p′-
500 g/hr of BPA/PhOH was melted in a flask under nitrogen and charged into a double-tube cylinder kept warm. Next, this melt was led to a dehydration tower at a rate of 250 g/hr, where it was dehydrated under conditions of 140°C and 100 mmHg, and the dehydrated melt was continuously extracted from the bottom of the dehydration tower and immediately supplied to a phenol recovery tower. did. A 10-stage older-stage distillation tower was used as the phenol recovery tower, and the raw material from the dehydration tower was supplied to the fourth tray from the bottom. During phenol recovery distillation, the internal temperature of the flask at the bottom of the column is 20 mm.
The temperature was maintained at 163°C under Hg. Here, 67.2 g/hr of recovered phenol was obtained from the top of the column, which was supplied as supplementary phenol to the continuous condensation reaction. On the other hand, 174.8 g/hr of molten p,p'-BPA was obtained from the bottom of the phenol recovery tower. Next, the molten p,p'-BPA and weakly acidified hot water were continuously supplied to an oil-water mixing tank to mix the oil and water. The mixed oil and water obtained in this way is thoroughly stirred and sent to a hot water washing tank, and after thorough stirring and washing, it is separated into an oil phase and a water phase in a standing room, and the separated oil phase is 233.3g/hr. Extracted continuously. p,p′-BPA extracted from hot water cleaning tank
An oil phase mainly composed of . The slurry mixture thus obtained was introduced into a receiver and subjected to solid-liquid separation every hour using a centrifugal separator kept warm. The wet cake obtained had a weight of 173.3 g/hr. Next, this wet cake was placed in a vacuum dryer and dried under heating and reduced pressure conditions to obtain purified p,p'-
Obtained 167.3 g/hr of BPA. Purified p,p′-BPA thus obtained
The quality is shown in Table 4.

[Table] Examples 2 to 11 Using the reaction apparatus shown in Figure 1, a series of reactions were carried out in the same manner as in Example 1, except that the conditions shown below (see Table 5) were changed in each example. Continuous experiments were conducted to evaluate the quality of the purified p,p'-BPA produced. In the examples shown below, some of the continuous reaction conditions of Example 1 are shown in Table 5,
Purified p,p′-BPA from crude p,p′-BPA・PhOH
The manufacturing experiment was conducted in the same manner as in Example 1. In Example 2 and Example 3, conditions were set so that the molar ratio of total phenol to total acetone in the reaction system was 6/1 (Example 2) and 10/1 (Example 3), respectively. As in Example 1, continuous experiments were conducted while circulating the reaction mother liquor. In Examples 4 and 5, conditions were set so that the number of moles of HCl contained in 1000 g of the reaction mixture in the reaction system was 1 mole (Example 4) and 5 moles (Example 5), respectively. As in Example 1, continuous experiments were conducted while circulating the reaction mother liquor. In Examples 6 and 7, conditions were set so that the reaction temperature in the reaction system was 60°C (Example 6) and 40°C (Example 7), and the reaction mother liquor was heated in the same manner as in Example 1. Continuous experiments were conducted while cycling. In Examples 8 and 9, conditions were set so that the average residence time in the reactor was 4 hours (Example 8) and 6 hours (Example 9), respectively, and the same procedure as in Example 1 was carried out. Continuous experiments were conducted while circulating the reaction mother liquor. In Examples 10 and 11, the weight ratio of the aqueous phase mother liquor to the oil phase mother liquor in the slurry reaction mixture was adjusted to 0.03 (Example 10) by changing the ratio of the hydrochloric acid aqueous phase supplied into the reaction tank. ) and 1.2
(Example 11) Conditions were set so that the reaction mother liquor was circulated in the same manner as in Example 1, and continuous experiments were conducted. Reaction results of 350 hours of continuous reaction for Examples 2 to 11, and purified p,
p′-Quality evaluation and purification of BPA/PhOH p, p′-
Table 5 shows the quality evaluation of BPA.

【table】

[Table] Comparative Example 1 The following experiment was conducted using the continuous condensation reaction apparatus shown in FIG. The aqueous phase mother liquor obtained in the continuous reaction was completely recycled and reused without being extracted from the system, and the continuous condensation reaction was carried out while the mother liquor was circulated with the other reaction conditions set to the same conditions as in Example 1. carried out. As a result, water produced in the condensation reaction gradually accumulated in the system, making it virtually impossible to continue the continuous reaction while maintaining predetermined reaction conditions. Therefore, from 30 hours after the start of the reaction, the continuous reaction was continued by gradually increasing the circulation amount of the aqueous phase mother liquor according to the rate of increase. As a result, as shown in Table 6 below, the residence time in the reaction system gradually became shorter, and the conversion rate of acetone decreased accordingly.

[Table] As shown in Table 6, if the continuous reaction is continued while increasing the circulation rate of the aqueous phase mother liquor, the operating time will be 500 hours.
By the time this was reached, the residence time was 2.6 hours, which was about half that of Example 1, and the acetone conversion rate had dropped to 86%. Furthermore, the weight ratio of the aqueous phase to the oil phase in the reaction mixture was 2.1. In this way, when the operating time reached 500 hr, it was no longer possible to continue the reaction under suitable conditions. Comparative Example 2 In the continuous condensation reaction of Example 1, the crude p,p'-BPA/PhOH obtained after 300 hours was melted as it was without neutralization and purification, and p, p′-BPA was produced. Produced p, p′-
The quality of BPA was as shown in Table 7.

【table】

[Table] As is clear from comparing the above examples, according to the present invention, p, p'-BPA of higher quality can be selectively produced at a higher yield than in the case of the comparative example. Moreover, it can be seen that it can be manufactured economically. This is a particularly remarkable effect when considering the uses of p,p'-BPA and the many conventional improvement methods.

[Brief explanation of the drawing]

FIG. 1 is a system diagram of a mother liquor circulation type continuous condensation reaction apparatus used in one embodiment of the present invention. FIG. 2 is a graph showing the relationship between the reaction time of the circulating oil phase mother liquor and crude p,p'-BPA·PhOH and the degree of coloration at 480 nm in Example 1 of the present invention. 1 and 2: Replenishment raw material tank, 3: Circulating oil phase mother liquor tank, 4: Circulating water phase mother liquor tank, 11-13:
Reaction tank, 14: Receiver, 15: Centrifugal separator, 16:
Oil/water separator, 40: Dissolution tank, 42: Neutralization tank, 43
and 47: oil/water separation tank, 44: crystallization tank, 46: centrifugal separator, 70: melting tank, 71: dehydration tower, 72:
Phenol recovery tower (decomposition tower), 73: oil-water mixing tank,
74: Hot water washing tank, 75: Crystallization tank, 76: Centrifugal separator, 77: Vacuum dryer.

Claims (1)

[Scope of Claims] 1. A method for producing 2,2-bis(4-hydroxyphenyl)propane by reacting phenol and acetone in the presence of a hydrochloric acid-containing catalyst in a continuous process, comprising (A) a reactor containing The reaction is carried out by continuously charging replenishing phenol, circulating phenol as described below, replenishing acetone, replenishing hydrogen chloride or hydrochloric acid, circulating oil phase mother liquor as described later, and circulating water phase mother liquor as described later, and as a reaction mixture in the reaction system, crude 2, a step of forming a slurry reaction mixture consisting of crystals of a phenol adduct of 2-bis(4-hydroxyphenyl)propane and a two-liquid phase reaction mother liquor consisting of an oil phase mother liquor and an aqueous phase mother liquor; a step of extracting the slurry reaction mixture and separating it into a phenol adduct of crude 2,2-bis(4-hydroxyphenyl)propane and the two-liquid phase reaction mother liquor; (C) the step obtained in step (B); The two-liquid phase mother liquor is separated into an oil phase mother liquor and an aqueous phase mother liquor, and the oil phase mother liquor is circulated through the reactor as a circulating oil phase mother liquor. A portion of the water phase mother liquor is extracted and the remainder is used as circulating water. (D) dissolving the phenol adduct of crude 2,2-bis(4-hydroxyphenyl)propane obtained in step (B) in a phenolic solvent, and dissolving the crude 2,2-bis(4-hydroxyphenyl)propane phenol adduct obtained in step (B) in a phenolic solvent; After neutralizing hydrogen chloride or hydrochloric acid contained in the phenol adduct of 2-bis(4-hydroxyphenyl)propane with a base, the phenol adduct of 2,2-bis(4-hydroxyphenyl)propane is crystallized. Purification 2.
A step of obtaining a phenol adduct of 2-bis(4-hydroxyphenyl)propane, (E) heating the purified phenol adduct of 2,2-bis(4-hydroxyphenyl)propane obtained in the above step (D). By doing phenol and 2,2
- a step of decomposing into bis(4-hydroxyphenyl)propane, (F) phenol and 2,2-bis(4-hydroxyphenyl) from the thermal decomposition product of step (E);
a step of recovering propane; and (G) a step of circulating the phenol recovered in the step (F) as circulating phenol to the reactor of the step (A) or as a phenol solvent to the step (D). High purity characterized by containing 2,
A method for producing 2-bis(4-hydroxyphenyl)propane. 2. The method according to claim 1, wherein in step (C), when circulating the oil phase mother liquor, a portion of the oil phase mother liquor is extracted and the remainder is used as the circulating oil phase mother liquor. 3 A water-containing composition in which the phenolic solvent of step (D) forms a two-liquid phase consisting of an oil phase and an aqueous phase when the phenol adduct of the crude 2,2-bis(4-hydroxyphenyl)propane is dissolved. The method according to claim 1, wherein the phenol is a phenol. 4. The method according to claim 1, wherein in step (F), the recovered 2,2-bis(4-hydroxyphenyl)propane is further washed with hot water.