JP2022114119A - Method for producing bisphenol and method for producing polycarbonate resin - Google Patents

Abstract

To provide a method for producing bisphenol with a good yield, and a method for producing a polycarbonate resin having a good quality using the bisphenol obtained by the method for producing the bisphenol.SOLUTION: A method for producing bisphenol includes: a reaction step A2 of producing bisphenol from aromatic alcohol and ketone or aldehyde; a purification step B2 of supplying water to the bisphenol product obtained in the step A2, and oil-water separating the bisphenol product at 60°C or higher and 95°C or lower; a crystallization step C2 of crystallizing the oil phase obtained in the step B2, and obtaining a slurry liquid containing the bisphenol; a reaction step A1 of producing bisphenol from aromatic alcohol and ketone or aldehyde; a purification step B1 of supplying water to a bisphenol product obtained in the step A1, and oil-water separating the bisphenol product at 60°C or higher and 95°C or lower; and a recycling step D2 of supplying a water phase removed by the oil-water separation to the step B2.SELECTED DRAWING: Figure 2

Description

The present invention relates to a method for producing bisphenol. The present invention also relates to a method for producing a polycarbonate resin using the bisphenol.

Bisphenol is useful as a raw material for polymeric materials such as polycarbonate resins, epoxy resins, and aromatic polyester resins. As representative bisphenols, for example, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane and the like are known (Patent Documents 1 and 2 reference).

JP 2014-40376 A Japanese Patent Application Laid-Open No. 2020-37530

Bisphenol is used in a wide range of applications as a raw material for various resins such as polycarbonate resins, and its applications are expected to expand in the future.

Generally, bisphenol production employs a method of condensing a ketone or aldehyde with an aromatic alcohol in the presence of an acid catalyst to produce bisphenol (see Patent Documents 1 and 2).

For example, in Examples of Patent Document 1, hydrochloric acid is added to a mixture of ortho-cresol and acetone, and after stirring, 95% by mass of sulfuric acid is added dropwise over 0.7 to 2 hours to obtain a bisphenol compound. Have been described.

According to Patent Document 2, by dissolving the generated bisphenol and washing the organic phase containing bisphenol with water, bisphenol with excellent color tone can be produced. In general, the more times the washing is performed, the higher the quality of bisphenol can be produced, but the amount of bisphenol that flows out into the water phase also increases. In the production of ton-scale bisphenol, the amount of water and wastewater used for washing the bisphenol-containing organic phase is enormous, and the bisphenol flowing into the wastewater is a loss and cannot be ignored. For the efficient production of bisphenol, the establishment of a recovery method for bisphenol in the aqueous phase has been an issue.
SUMMARY OF THE INVENTION It is an object of the present invention to provide a method for producing bisphenol with a good yield. Another object of the present invention is to provide a method for producing a polycarbonate resin of good quality by using the bisphenol obtained by the method for producing bisphenol.

As a result of intensive studies to solve the above problems, the present inventors separated oil and water after producing bisphenol, and supplied the aqueous phase containing bisphenol to the previous step as it is or after performing pretreatment, The present inventors have found that bisphenol can be produced with good yield by reusing the bisphenol that has flowed out to the water phase, and have completed the present invention.

That is, the present invention relates to the following inventions.
[1] Reaction step A2 for producing bisphenol from an aromatic alcohol and a ketone or aldehyde;
A refining step B2 in which water is supplied to the bisphenol product obtained in the step A2 and oil-water separation is performed at 60° C. or higher and 95° C. or lower, and a slurry liquid containing bisphenol is obtained by crystallizing the oil phase obtained in the step B2. a crystallization step C2 to obtain, and a reaction step A1 of producing bisphenol from an aromatic alcohol and a ketone or aldehyde, and water is supplied to the bisphenol product obtained in the step A1, and the oil-water including a purification step B1 to separate,
A method for producing bisphenol, comprising a recycling step D2 in which the aqueous phase removed by the oil-water separation in the step B1 is supplied to the step B2 as it is or after pretreatment.
[2] The method for producing bisphenol according to [1], wherein the aqueous phase supplied in step D2 has a pH of 7 or more and 13 or less.
[3] In step D2, the aqueous phase removed by oil-water separation is concentrated, and the resulting aqueous phase concentrate is supplied to the bisphenol product obtained in step A2; A process for the preparation of the described bisphenol.
[4] The step D2 extracts bisphenol from the aqueous phase removed by the oil-water separation, and supplies the obtained bisphenol extract to the bisphenol product obtained in the step A2, [1] or [2]. The method for producing bisphenol according to .
[5] In step D2, the aqueous phase removed by oil-water separation is subjected to solid-liquid separation, and the resulting aqueous phase solids are supplied to the bisphenol product obtained in step A2, [1] or [2 ] The method for producing bisphenol according to .
[6] The purification step B1 and/or purification step B2 includes a first step in which the pH of the removed aqueous phase is acidic, a second step in which the pH of the removed aqueous phase is basic, and a removal The method for producing bisphenol according to any one of [1] to [5], comprising in this order a third step in which the pH of the aqueous phase obtained is neutral.
[7] The bisphenol is 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4-hydroxy The bisphenol according to any one of [1] to [6], including one or more selected from phenyl)phenylethane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane manufacturing method.
[8] A method for producing a polycarbonate resin, comprising a step of polymerizing polycarbonate using bisphenol produced by the method for producing bisphenol according to any one of [1] to [7].

According to the present invention, oil-water separation is performed after bisphenol is produced, and the aqueous phase containing bisphenol is supplied to the previous step as it is or after pretreatment, and the bisphenol that has flowed out to the aqueous phase is reused. Provided is an efficient method for producing bisphenol capable of producing bisphenol with a good yield and reducing the amount of wastewater. Moreover, using the bisphenol produced by the method for producing bisphenol, a polycarbonate resin can be produced efficiently.

It is a bisphenol manufacturing flow chart of a reference example. 1 is a bisphenol production flow diagram of Example 1. FIG. 2 is a bisphenol production flow diagram of Example 2. FIG. 1 is a bisphenol production flow diagram of Example 3. FIG. 1 is a bisphenol production flow diagram of Example 4. FIG. 1 is a bisphenol production flow diagram of Example 5. FIG.

Embodiments of the present invention will be described in detail below. is not limited to the contents of In addition, when the expression "-" is used in this specification, it is used as an expression including numerical values or physical property values before and after it.

One embodiment of the present invention is a method for producing bisphenol for obtaining bisphenol from an aromatic alcohol and a ketone or an aldehyde, wherein a reaction step A for producing bisphenol from an aromatic alcohol and a ketone or an aldehyde; A refining step B in which water is supplied to the bisphenol product obtained in step B and oil-water separation is performed at 60° C. or higher and 95° C. or lower, and the oil phase obtained in the step B is crystallized to obtain a slurry liquid containing bisphenol. In the method of performing multiple refining cycles including step C, the aqueous phase removed by the oil-water separation in the step B is supplied as it is or after pretreatment to the step B in the downstream refining cycle. and The purification cycle may be batch type or continuous type. For the sake of explanation, the steps of the first cycle may be expressed as steps A1 and B1, respectively, and the steps of the second cycle, which is the next cycle, may be expressed as steps A2 and B2, respectively.

The present inventors improved the yield of bisphenol by recycling and supplying the aqueous phase containing bisphenol removed in the purification step B as it is or after pretreatment to the step B in the downstream purification cycle, and We found that it is possible to reduce the amount of wastewater. The downstream purification cycle may be the immediately following purification cycle or may be the purification cycle after multiple purification cycles.

<Method for producing bisphenol: reaction step A>
This embodiment includes a reaction step A in which bisphenol is produced by a condensation reaction between an aromatic alcohol and a ketone or aldehyde in the presence of an acid catalyst.

[Bisphenol]
The bisphenol produced is usually a compound represented by the following general formula (1).

R ¹ to R ⁴ each independently include a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, an amino group and the like. Alkyl groups, alkoxy groups, aryl groups and the like may be substituted or unsubstituted. For example, hydrogen atom, fluoro group, chloro group, bromo group, iodo group, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n- pentyl group, i-pentyl group, n-hexyl group, n-heptyl group, n-octyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n -propoxy group, i-propoxy group, n-butoxy group, i-butoxy group, t-butoxy group, n-pentyloxy group, i-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n- octyloxy group, n-nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group,
cycloheptyl group, cyclooctyl group, cyclododecyl group, benzyl group, phenyl group, tolyl group, 2,6-dimethylphenyl group and the like.
Of these, R ² and R ³ are preferably hydrogen atoms because the condensation reaction is difficult to proceed if they are sterically bulky.

^R5 and ^R6 each independently include a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. Alkyl groups, alkoxy groups, aryl groups and the like may be substituted or unsubstituted. For example, hydrogen atom, methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, i-butyl group, t-butyl group, n-pentyl group, i-pentyl group, n-hexyl group , n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n-propoxy group, i -propoxy group, n-butoxy group, i-butoxy group, t-butoxy group, n-pentyloxy group, i-pentyloxy group, n-hexyloxy group, n-heptyloxy group, n-octyloxy group, n -nonyloxy group, n-decyloxy group, n-undecyloxy group, n-dodecyloxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, benzyl group, phenyl group, tolyl group, 2,6-dimethylphenyl group and the like.

R ⁵ and R ⁶ may be bonded or bridged to each other between the two groups, and R ⁵ and R ⁶ may be bonded together with adjacent carbon atoms to form a cycloalkylidene group. For example, cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3,3,5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclo dodecylidene, fluorenylidene, xanthonylidene, thioxanthonylidene and the like.

Specifically, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethyl phenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, 3,3-bis(4-hydroxyphenyl)pentane , 3,3-bis(4-hydroxy-3-methylphenyl)pentane, 2,2-bis(4-hydroxyphenyl)pentane, 2,2-bis(4-hydroxy-3-methylphenyl)pentane, 3, 3-bis(4-hydroxyphenyl)heptane, 3,3-bis(4-hydroxy-3-methylphenyl)heptane, 2,2-bis(4-hydroxyphenyl)heptane, 2,2-bis(4-hydroxy -3-methylphenyl)heptane, 4,4-bis(4-hydroxyphenyl)heptane, 4,4-bis(4-hydroxy-3-methylphenyl)heptane, 1,1-bis(4-hydroxyphenyl)phenyl Examples include ethane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane, but are not limited to these.

Among these, suitable bisphenols are 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, and 1,1-bis from the group consisting of (4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)phenylethane, 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane Either selected.

一般式（２）において、Ｒ^１～Ｒ^４は、上記一般式（１）のＲ^１～Ｒ^４におけるものと同義である。 [Aromatic alcohol]
Aromatic alcohols are usually compounds represented by the following general formula (2).

In general formula (2), R ¹ to R ⁴ have the same definitions as R ¹ to R ⁴ in general formula (1) above.

If R ² and R ³ are sterically bulky, the condensation reaction is difficult to proceed, so they are preferably hydrogen atoms. R ¹ to R ⁴ are each independently preferably a hydrogen atom, an alkyl group, an alkoxy group, an aryl group or an amino group, more preferably a hydrogen atom or an alkyl group. Examples include compounds in which R ¹ and R ⁴ are each independently a hydrogen atom or an alkyl group, and R ² and R ³ are a hydrogen atom. The alkyl group can be an alkyl group having 1 to 12 carbon atoms or an alkyl group having 1 to 6 carbon atoms.

Specifically, the compounds represented by the general formula (2) include phenol, methylphenol (cresol), dimethylphenol (xylenol), ethylphenol, propylphenol, butylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, aminophenol, benzylphenyl, phenylphenol and the like. Among these, any one selected from the group consisting of phenol, methylphenol and dimethylphenol is preferable, methylphenol or dimethylphenol is more preferable, and methylphenol is still more preferable.

一般式（３）において、Ｒ^５、Ｒ^６は、上記一般式（１）のＲ^５、Ｒ^６におけるものと同義である。 [ketone or aldehyde]
A ketone or aldehyde is usually a compound represented by the following general formula (3).

In general formula (3), R ⁵ and R ⁶ have the same definitions as R ⁵ and R ⁶ in general formula (1) above.

Preferably, ^R5 and ^R6 are each independently a hydrogen atom, an alkyl group, an aryl group, or a cycloalkylidene group formed by combining ^R5 and ^R6 together with adjacent carbon atoms . The alkyl group can be an alkyl group having 1 to 12 carbon atoms or an alkyl group having 1 to 6 carbon atoms. Examples include compounds in which R ⁵ and R ⁶ are each independently an alkyl group or a cycloalkylidene group formed by combining R ⁵ and R ⁶ with adjacent carbon atoms.

Specific examples of compounds represented by general formula (3) include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentanaldehyde, hexanaldehyde, heptanaldehyde, octanaldehyde, nonanaldehyde, decanealdehyde, undecanealdehyde, and dodecanealdehyde. aldehydes such as; acetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, decanone, undecanone, dodecanone; ketones such as benzaldehyde, phenylmethylketone, phenylethylketone, phenylpropylketone, cresylmethylketone, cresyl Aryl alkyl ketones such as ethyl ketone, cresyl propyl ketone, xylyl methyl ketone, xylyl ethyl ketone, xylyl propyl ketone; cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone , cyclodecanone, cycloundecanone, cyclododecanone, and other cyclic alkane ketones.

If the amount of ketone or aldehyde is large relative to the raw material aromatic alcohol, the amount of ketone or aldehyde tends to increase. For these reasons, the lower limit of the molar ratio of aromatic alcohol to ketone or aldehyde ((moles of aromatic alcohol/moles of ketone) or (moles of aromatic alcohol/moles of aldehyde)) is preferably The molar ratio is 1.5 or more, more preferably 1.6 or more, and still more preferably 1.7 or more. Moreover, the upper limit is preferably 15 or less, more preferably 10 or less, and still more preferably 8 or less.

[Acid catalyst]
Acid catalysts used in the method for producing bisphenol include sulfuric acid, hydrochloric acid, hydrogen chloride gas, phosphoric acid, aromatic sulfonic acids such as p-toluenesulfonic acid, and aliphatic sulfonic acids such as methanesulfonic acid.
The acid catalyst is preferably one or more selected from the group consisting of sulfuric acid, hydrochloric acid, and hydrogen chloride gas, more preferably sulfuric acid and/or hydrogen chloride gas. Sulfuric acid is particularly preferable as the acid catalyst from the viewpoints of excellent reaction efficiency, non-volatility of the catalyst, and less burden on equipment.

Sulfuric acid is an acidic liquid represented by the chemical _{formula H2SO4} . Sulfuric acid is generally used as an aqueous sulfuric acid solution diluted with water, and is called concentrated sulfuric acid or dilute sulfuric acid depending on its concentration. For example, dilute sulfuric acid is an aqueous sulfuric acid solution having a mass concentration of less than 50% by mass.
If the concentration of sulfuric acid used (the concentration of the sulfuric acid aqueous solution) is low, the amount of water increases, making it difficult for the reaction to produce bisphenol to proceed, and the reaction time to produce bisphenol becomes longer, resulting in efficient production of bisphenol. can be difficult. Therefore, the concentration of sulfuric acid to be used is preferably 70% by mass or more, more preferably 75% by mass or more, and even more preferably 80% by mass or more. Moreover, the upper limit of the concentration of sulfuric acid to be used is usually 99.5% by mass or less or 99% by mass or less.

If the molar ratio of sulfuric acid to the raw material aromatic alcohol (number of moles of sulfuric acid/number of moles of aromatic alcohol) is small, the sulfuric acid will be diluted by water produced as a by-product as the condensation reaction progresses, and the reaction will take time. . Further, when the amount is large, the aromatic alcohol may be sulfonated to produce a large amount of aromatic alcohol sulfonic acid. For these reasons, the molar ratio of sulfuric acid to the raw material aromatic alcohol is preferably 0.01 or more, more preferably 0.05 or more, and still more preferably 0.1 or more. Also, the upper limit is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less.

[thiol promoter]
A thiol cocatalyst can be used as a cocatalyst in the reaction of condensing an aromatic alcohol with a ketone or aldehyde. Thiol promoters include, for example, mercaptocarboxylic acids such as mercaptoacetic acid, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 4-mercaptobutyric acid, methylmercaptan, ethylmercaptan, propylmercaptan, butylmercaptan, pentyl Mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan (decanethiol), undecyl mercaptan (undecanethiol), dodecyl mercaptan (dodecanethiol), tridecyl mercaptan, tetradecyl mercaptan, pentadecyl mercaptan, mercaptophenol and the like.

The molar ratio of thiol promoter to ketone or aldehyde ((moles of thiol promoter/moles of ketone) or (moles of thiol promoter/moles of aldehyde)) is less The effect of improving the selectivity of bisphenol cannot be obtained, and if it is too much, it may be mixed with bisphenol and deteriorate the quality. For these reasons, the lower limit of the molar ratio of thiol promoter to ketone or aldehyde is preferably 0.001 or more, more preferably 0.005 or more, and still more preferably 0.01 or more. Moreover, the upper limit thereof is preferably 1 or less, more preferably 0.5 or less, and still more preferably 0.1 or less.

[Organic solvent]
The reaction to produce bisphenol may be carried out in the presence of an organic solvent. Organic solvents include aromatic hydrocarbons, aliphatic alcohols, aliphatic hydrocarbons, and the like. These solvents may contain one or more. For example, a mixed solvent of aromatic hydrocarbon and aliphatic alcohol may be used.

Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene.

Examples of aliphatic hydrocarbons include hexane, heptane, octane, nonane, decane, undecane, dodecane and the like.

Examples of aliphatic alcohols include methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, monohydric alkyl alcohols such as n-octanol, n-nonanol, n-decanol, n-undecanol and n-dodecanol; and polyhydric alcohols such as ethylene glycol, diethylene glycol and triethylene glycol.
From the viewpoint of reaction efficiency and the like, the aliphatic alcohol is preferably a monovalent alkyl alcohol having 1 to 12 carbon atoms, more preferably a monovalent alkyl alcohol having 1 to 8 carbon atoms.

A large amount of aromatic alcohol as a raw material may be used as a substitute for the organic solvent. In this case, the unreacted aromatic alcohol becomes a loss, but the loss can be reduced by recovering and refining it by distillation or the like and reusing it.

When using an organic solvent, if the mass ratio of the organic solvent to the raw material ketone or aldehyde ((mass of ketone/mass of organic solvent) or (mass of aldehyde/mass of organic solvent)) is too high, the ketone or aldehyde , the reaction with the aromatic alcohol is difficult, and the reaction takes a long time. If the amount is too small, the generated bisphenol may cause poor mixing, or the increase in the amount of ketones or aldehydes may be promoted. For these reasons, the mass ratio of the organic solvent to the ketone or aldehyde is preferably 0.5 or more, more preferably 1 or more. Moreover, the upper limit may be adjusted according to the type of organic solvent within a range in which precipitation of bisphenol occurs, and can be 50 or less and 30 or less.

A solvent with a low solubility of bisphenol is used because the bisphenol that is formed tends to precipitate and the loss when recovering bisphenol from the reaction solution after the reaction is completed (for example, the loss to the filtrate during crystallization) can be reduced. is preferred. Solvents in which bisphenol has low solubility include, for example, aromatic hydrocarbons. For this reason, the organic solvent preferably contains an aromatic hydrocarbon as a main component, and preferably contains 55% by mass or more of the aromatic hydrocarbon in the organic solvent, more preferably 70% by mass or more, and 80% by mass. % or more is more preferable.

In the condensation reaction between the aromatic alcohol and the ketone or aldehyde, it is preferable to supply the solution containing the aromatic alcohol and the acid catalyst with the solution containing the ketone or aldehyde to carry out the condensation reaction. The method of supplying the solution containing this ketone or aldehyde can be a method of supplying it all at once or a method of supplying it dividedly. A method of dividing and supplying, such as supplying, is preferable.

The solution containing the aromatic alcohol and the acid catalyst may consist of the aromatic alcohol and the acid catalyst, or may contain other components. For example, a solution containing an aromatic alcohol, an acid catalyst and an organic solvent may be used.
Also, the solution containing ketones or aldehydes may consist of ketones or aldehydes, and may contain other components. For example, when using a thiol co-catalyst, the thiol co-catalyst is preferably pre-mixed with the ketone or aldehyde before being subjected to the reaction. The method of mixing the thiol cocatalyst and the ketone or aldehyde may include supplying the ketone or aldehyde to the thiol cocatalyst, or supplying the ketone or aldehyde to the thiol cocatalyst. Also, the solution containing ketones or aldehydes may contain an organic solvent.

If the reaction temperature is too low, the condensation reaction will be difficult to proceed. Also, if the reaction temperature is too high, the self-condensation reaction of acetone or ketone, which is a side reaction, proceeds, and when a thiol, which is a co-catalyst, is used, the oxidative decomposition of the thiol tends to proceed, so it is preferably 50 ° C. or less, more preferably 45° C. or less, and still more preferably 40° C. or less.

The reaction time of the condensation reaction is appropriately adjusted depending on the reaction conditions such as the type of bisphenol to be produced, the reaction temperature, and the scale of production. good too. The time is preferably 30 hours or less, more preferably 25 hours or less, still more preferably 20 hours or less, because the bisphenol produced is decomposed if it is long. The lower limit of the reaction time is usually 0.5 hours or longer, preferably 1 hour or longer, and more preferably 1.5 hours or longer.
The reaction time also includes the mixing time of the ketone or aldehyde and the aromatic alcohol. For example, when a ketone or aldehyde is supplied to a mixed solution of an aromatic alcohol and an acid catalyst over 1 hour and then reacted for 1 hour, the reaction time is 2 hours.
Also, the reaction can be stopped by, for example, adding water or a base in an amount equal to or greater than the amount of the acid catalyst used to lower the concentration of the acid catalyst.

[Reactor]
Since the reaction for producing bisphenol proceeds with a strong acid as a catalyst, it is preferable that the surface of the inner wall of the reaction tank is made of a material that is resistant to corrosion. In particular, it is preferable to use a reactor made of glass lining which is excellent in corrosion resistance.

[Purification step B]
The bisphenol product obtained in step A is subjected to purification step B. The refining step B is a step of supplying water to the bisphenol product obtained in the step A and separating the oil and water at 60°C or higher and 95°C or lower. The temperature for oil-water separation is preferably 65°C or higher, and more preferably 90°C or lower.

The water to be supplied may be pure water, an acidic aqueous solution containing an acid, or a basic aqueous solution containing an alkali. When pure water is used, it is preferable that the purity is high, and it is preferably pure water with an electrical conductivity of 10 μS / cm or less, more preferably 5 S / cm or less, and a purity of 1 μS / cm or less. Water is more preferred.
When acid cleaning is performed with an aqueous solution containing an acid, it is preferable to use an aqueous solution having a pH of 1 or more and 6 or less. When alkaline cleaning is performed with an aqueous solution containing alkali, it is preferable to use an aqueous solution with a pH of 7 or more and 13 or less.

Purification step B may be carried out multiple times, and preferably repeated until the electrical conductivity of the aqueous phase separated in purification step B becomes 10 μS/cm or less, from the viewpoint of the quality of the bisphenol obtained. Most preferably, the aqueous phase separated in the purification step B has an electric conductivity of 10 μS/cm or less and a neutral pH of 6.5 to 7.5.
The aqueous phase separated (removed) in the purification step B may be an acidic aqueous solution containing an acid, a basic aqueous solution containing an alkali, or an aqueous solution containing a neutral salt. good.
When the aqueous phase separated in the purification step B is an acidic aqueous solution containing an acid (for example, pH is 1 or more and 6 or less), metals that deteriorate the color tone of bisphenol can be efficiently removed from the organic phase containing bisphenol. . Further, when the aqueous phase separated in the purification step B is a basic aqueous solution containing alkali (e.g. pH 8 or more and 14 or less), an acidic component that poisons the catalyst when polymerizing polycarbonate from an organic phase containing bisphenol. can be effectively removed. For these reasons, the aqueous phase separated in the purification step B is preferably an acidic aqueous solution containing an acid and a basic aqueous solution containing an alkali. After obtaining the acidic aqueous solution containing an acid, the base containing an alkali Most preferably, after obtaining a basic aqueous solution containing alkali, washing is repeated until the electric conductivity of the separated aqueous phase becomes 10 μS/cm or less. That is, purification step B includes a first step in which the pH of the removed aqueous phase is acidic, a second step in which the pH of the removed aqueous phase is basic, and a neutral pH of the removed aqueous phase. A third step in this order is preferred.
All of the aqueous phases separated in the purification step B may be mixed, or separated into an acidic aqueous solution, a basic aqueous solution, and a neutral aqueous solution.

[Recycling process D]
This embodiment is characterized by including a recycling step D in which the aqueous phase separated in the purification step B is supplied to the purification step B in the downstream purification cycle and recycled again. Recycling process D greatly improves the yield of bisphenol and reduces the amount of wastewater.
Although there are no restrictions on the properties of the water phase to be recycled, the pH of the water phase to be recycled is preferably 7 or more, and preferably 13 or less, in consideration of the quality of bisphenol as a raw material for polycarbonate. If the aqueous phase separated in the purification step B is out of the preferred pH range, acid and/or alkali can be supplied to adjust the pH to within the preferred range. However, an adjustment tank for pH adjustment is required separately, which may limit the facility. Therefore, the acidic aqueous solution containing the acid separated in the purification step B is recycled to the step of washing with the acidic aqueous solution (first washing), and the basic aqueous solution containing alkali is recycled to the step of washing with the alkaline aqueous solution (alkaline washing). preferably.
The water phase to be recycled may be returned to the step before the crystallization step C described later, may be supplied to the bisphenol product obtained in the step A, and may be used as water to be supplied to the bisphenol product in the purification step B. However, it is preferably used as the water to be supplied to the bisphenol product in the purification step B.

The water phase to be recycled may be recycled as it is, or may be recycled after pretreatment. For example, the following (i) to (iii) can be mentioned as a mode in which recycling is performed after pretreatment.
(i) A form in which the aqueous phase removed by oil-water separation is concentrated and the resulting aqueous phase concentrate is supplied to the bisphenol product obtained in step A, i.e. to step B,
(ii) extracting bisphenol from the aqueous phase removed by oil-water separation and feeding the resulting bisphenol extract to the bisphenol product obtained in step A, i.e. to step B;
(iii) solid-liquid separation of the aqueous phase removed by oil-water separation, and supply of the resulting aqueous phase solids to the bisphenol product obtained in step A, i.e., to step B;
These pretreatments can be carried out by conventional methods.

[Crystallization step C]
The oil phase obtained in the refining step is crystallized in the crystallization step C to obtain a slurry liquid containing bisphenol. Crystallization is carried out by cooling the oil phase to crystallize bisphenol. Although the temperature for crystallization is not particularly limited, it is generally 10°C or higher, preferably 15°C or higher, and generally 30°C or lower, preferably 25°C or lower.

[Applications of bisphenol]
The resulting bisphenol is used in various applications such as optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. Polyether resins, polyester resins, polyarylate resins, polycarbonate resins, polyurethane resins, Constituents, curing agents, additives, or precursors of various thermoplastic resins such as acrylic resins, thermosetting resins such as epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, and cyanate resins. and so on. It is also useful as an additive such as a color developer for heat-sensitive recording materials, an anti-fading agent, a bactericide, and an antibacterial and antifungal agent.

Among these, it is preferable to use it as a raw material (monomer) for thermoplastic resins and thermosetting resins, and more preferably as a raw material for polycarbonate resins and epoxy resins, because it can impart good mechanical properties. It is also preferably used as a developer, and more preferably used in combination with a leuco dye and a discoloration temperature regulator.

<Method for producing polycarbonate resin>
A method for producing a polycarbonate resin using the obtained bisphenol as a raw material will be described. The polycarbonate resin can be produced by a method of subjecting bisphenol and a diester carbonate such as diphenyl carbonate to transesterification reaction in the presence of an alkali metal compound and/or an alkaline earth metal compound, for example. The transesterification reaction can be carried out by appropriately selecting a known method, and an example using bisphenol and diphenyl carbonate as raw materials will be described below.

In the method for producing a polycarbonate resin, it is preferable to use an excess amount of diphenyl carbonate relative to bisphenol. The amount of diphenyl carbonate used relative to the bisphenol is preferably large from the viewpoint that the produced polycarbonate resin has few terminal hydroxyl groups and excellent thermal stability of the polymer. It is preferable that the amount is small from the viewpoint of easy production of the polycarbonate resin. For these reasons, the amount of diphenyl carbonate used per 1 mol of bisphenol is usually 1.001 mol or more, preferably 1.002 mol or more, and usually 1.3 mol or less, preferably 1.2 mol or less. is.

As a raw material supply method, the bisphenol and diphenyl carbonate of the present invention can be supplied in solid form, but it is preferable to melt one or both of them and supply them in a liquid state.

A transesterification catalyst is usually used when producing a polycarbonate resin by the transesterification reaction between diphenyl carbonate and bisphenol. Preference is given to using alkali metal compounds and/or alkaline earth metal compounds as transesterification catalysts. These may be used alone, or two or more of them may be used in any combination and ratio. Practically, it is desirable to use an alkali metal compound.

The amount of catalyst used per 1 mol of bisphenol or diphenyl carbonate is usually 0.05 μmol or more, preferably 0.08 μmol or more, more preferably 0.10 μmol or more, and usually 100 μmol or less, preferably It is 50 μmol or less, more preferably 20 μmol or less.

When the amount of the catalyst used is within the above range, it is easy to obtain the polymerization activity necessary for producing a polycarbonate resin having a desired molecular weight, and the polymer hue is excellent, and excessive branching of the polymer does not proceed, It is easy to obtain a polycarbonate resin with excellent fluidity during molding.

In order to produce a polycarbonate resin by the above method, it is preferable to continuously supply both the above raw materials to a raw material mixing tank, and continuously supply the resulting mixture and a transesterification catalyst to a polymerization tank.
In the production of a polycarbonate resin by the transesterification method, both raw materials supplied to a raw material mixing tank are generally stirred uniformly and then fed to a polymerization tank in which a catalyst is added to produce a polymer.

EXAMPLES Hereinafter, the present invention will be described in more detail with reference to examples and comparative examples, but the present invention is not limited by the following examples as long as the gist thereof is not exceeded.

[Raw materials and reagents]
Orthocresol, toluene, sodium hydroxide, sulfuric acid, dodecanethiol, methanol, acetone, sodium hydrogencarbonate, and cesium carbonate were reagents manufactured by Wako Pure Chemical Industries, Ltd.
A product manufactured by Mitsubishi Chemical Corporation was used as diphenyl carbonate.

[analysis]
(Quantitative analysis of bisphenol)
Quantitative analysis of bisphenol was performed by high performance liquid chromatography under the following procedure and conditions.
・ Apparatus: LC-2010 Imtakt Scherzo SM-C18 manufactured by Shimadzu Corporation
3 μm 250×3.0 mm I.D. D.
・Low pressure gradient method ・Analysis temperature: 40°C
・Eluent composition:
A solution Ammonium acetate: acetic acid: dechlorinated water = 3.000 g: 1 ml: 1 liter solution B solution Ammonium acetate: acetic acid: acetonitrile = 1.500 g: 1 ml: 900 ml solution At analysis time 0 minutes, A solution : B solution = 60: 40 (volume ratio, hereinafter the same), analysis time 0 to 42 minutes, gradually change the eluent composition to A solution: B solution = 10: 90, analysis time 42 to 50 minutes A solution: B solution=10:90 was maintained.
・Flow rate: 0.34 mL/min ・Detection wavelength: 280 nm

(Measurement of pH)
The pH was measured using a pH meter "pH METERES-73" manufactured by Horiba, Ltd. on the aqueous phase at 25° C. taken out from the flask.

(Electrical conductivity)
The electrical conductivity was measured on the aqueous phase at 25° C. taken out from the flask using an electrical conductivity meter “COND METER D-71” manufactured by Horiba, Ltd.

(Terminal hydroxyl group concentration (OH) concentration of polycarbonate resin)
The terminal hydroxyl group concentration (OH) concentration of the polycarbonate resin was measured by colorimetry according to the titanium tetrachloride/acetic acid method (see Makromol. Chem. 88, 215 (1965)).

(Viscosity average molecular weight (Mv))
Viscosity average molecular weight (Mv) is obtained by dissolving polycarbonate resin in methylene chloride (concentration 6.0 g / L), measuring specific viscosity (ηsp) at 20 ° C. using Ubbelohde viscosity tube, viscosity average molecular weight according to the following formula (Mv) was calculated.
ηsp/C=[η](1+0.28ηsp)
[η]=1.23×10 ⁻⁴ Mv ^0.83

(Pellet YI)
The pellet YI (transparency of polycarbonate resin) was evaluated by measuring the YI value (yellowness index value) of polycarbonate resin pellets in reflected light according to ASTM D1925.
・Apparatus: Spectrophotometer CM-5 manufactured by Konica Minolta
·Measurement condition:
An SCE with a measuring diameter of 30 mm was selected. A calibration glass CM-A212 for petri dish measurement was fitted into the measurement part, and a zero calibration box CM-A124 was placed over it to perform zero calibration, followed by white calibration using a built-in white calibration plate. Next, measurement was performed using a white calibration plate CM-A210, L * was 99.40 ± 0.05, a * was 0.03 ± 0.01, b * was -0.43 ± 0.01, YI was -0.58±0.01.
The pellets were measured by packing them into a cylindrical glass container having an inner diameter of 30 mm and a height of 50 mm to a depth of about 40 mm. The operation of taking out the pellets from the glass container and measuring again was repeated twice, and the average value of the measured values of a total of three times was used.

<Reference example 1>
Reference Example 1 was carried out according to the flow shown in FIG.
[Reaction step A1]
280.0 g of toluene, 15.0 g of methanol, and 230.4 g of ortho-cresol are placed in a separable flask equipped with a thermometer, dropping funnel, jacket, and Ikari-type stirring blade under a nitrogen atmosphere, and the internal temperature is maintained at 10°C or less. While stirring, 95.0 g of 98% by mass sulfuric acid was added to prepare a mixed solution A. Next, 61.0 g of acetone (mass amount: 1.05 mol), 5.4 g of dodecanethiol, and 50.0 g of recovered toluene were added to the dropping funnel to obtain a mixed solution B. While the mixed liquid A was maintained at 10° C. or lower, the mixed liquid B in the dropping funnel was added dropwise to the mixed liquid A over 45 minutes while stirring. While the mixed liquid B was being dropped into the mixed liquid A, the generated bisphenol precipitated and became a slurry. Further, the reaction liquid was stirred for an additional hour while maintaining the temperature at 20° C. to obtain a slurry-forming reaction liquid.

[Purification step B1]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of desalted water was added to the organic phase, and the mixture was stirred at 80° C. and then oil-water separated. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask (first water wash).

120 g of a 3% by weight sodium hydrogencarbonate solution was added to the resulting organic phase, and the mixture was neutralized by stirring at 80° C. to separate oil and water. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 245 g of an organic phase and a basic aqueous phase (washed with alkaline water).
100 g of desalted water was added to the obtained organic phase, and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated three times to obtain 410 g of an aqueous phase after washing with water and 610 g of an organic phase in which bisphenol C was dissolved (second washing).

<Example 1>
Example 1 was carried out according to the flow shown in FIG.
[Reaction step A2]
It was carried out in the same manner as in Comparative Example 1 to obtain a slurry-forming reaction liquid.

[Purification step B2]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). To this organic phase, 100 g of the second water-washed aqueous phase obtained in Reference Example 1 was added (recycling step D2), stirred at 80° C., and then oil-water separated. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain 625 g of the first organic phase and 99 g of the aqueous phase after the first water washing (first water washing). The pH of the first water wash water phase was 1.2. Bisphenol C in the first organic phase is 35.9% by weight (the reaction yield (mol%) of bisphenol C based on cresol is the number of moles of bisphenol C produced in terms of cresol/the number of moles of raw material cresol × 100 (%) As a result, the reaction yield of bisphenol C was 82.3 mol% (35.9 [mass %] × mass of organic phase 625 [g] / 100 / molecular weight of bisphenol C 256 [g / mol mol])×2÷substance amount of charged cresol 2.13 [mol mol]).

110 g of the basic aqueous phase obtained in Reference Example 1 was added to the obtained first organic phase (recycling step D2), and the mixture was stirred at 80° C. for neutralization and oil-water separation. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 622 g of a second organic phase and 221 g of a basic aqueous phase (washed with alkaline water). The pH of the basic aqueous phase was 8.8. Bisphenol C in the second organic phase was 35.3% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 80.5 mol% (35.3 [mass%] × mass of organic phase 622 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).
100 g of the second water-washed aqueous phase obtained in Reference Example 1 was added to the obtained second organic phase (recycling step D2), and the mixture was stirred at 80°C to separate oil and water. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (second washing with water, first time). This operation was repeated again (second washing with water), 100 g of desalted water was added, and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask (second water wash, third time). This operation was repeated again (second water washing, 4th time) to obtain 404 g of the second water-washed aqueous phase and 618 g of a third organic phase in which bisphenol C was dissolved (second water washing). The pH of the aqueous phase after the second washing with water was 7.3. Bisphenol C in the third organic phase was 34.9% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 79.1 mol% (34.9 [mass%] × mass of organic phase 618 [g]÷100÷Molecular weight of bisphenol C 256 [g/mol])×2÷Substance amount of charged cresol 2.13 [mol mol]).

[Crystallization step C2]
The third organic phase in which bisphenol C obtained in the purification step was dissolved was heated at 80°C to 20°C.
and maintained at 20°C to precipitate bisphenol C. Then, after cooling to 10°C and reaching 10°C, solid-liquid separation was performed using a centrifuge to obtain a partially purified wet cake.
300 g of toluene was sprinkled on the obtained partially purified wet cake to wash it, and solid-liquid separation was performed using a centrifuge to obtain a purified wet cake.
Using an evaporator equipped with an oil bath, the obtained purified wet cake was subjected to distillation under reduced pressure at an oil bath temperature of 100 ° C. to remove the low-boiling components to give a white bisphenol C 192 g (0.750 mol, cresol-based yield of 0.750 mol×2÷2.13 mol×100=70.4 mol %). Of the 856 g of water used in the refining process, 513 g of water was recycled, giving a recycling rate of 60%.

<Example 2>
Example 2 was carried out according to the flow shown in FIG.
[Pretreatment process]
99 g of the first washed aqueous phase, 221 g of the basic aqueous phase, and 404 g of the second washed aqueous phase obtained in Example 1 are added to a 1 L separatory funnel together with 45 g of toluene and 1 g of methanol, and shaken for 20 minutes. After that, it was allowed to stand still to separate oil and water. The oil-water-separated aqueous phase was removed to obtain 50 g of bisphenol C extract.
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1 to obtain a slurry-forming reaction liquid.

[Purification step B2]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and then allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of desalted water was added to the organic phase, and the mixture was stirred at 80° C. and then oil-water separated. After the oil-water separation, the water phase was removed from the bottom of the separable flask to obtain 625 g of the first organic phase and 98 g of the water phase after the first water washing (first water washing). The pH of the first water wash water phase was 1.1. Bisphenol C in the first organic phase was 35.7% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 81.8 mol% (35.7 [mass%] × mass of organic phase 625 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

To the obtained first organic phase, 50 g of the bisphenol C extract obtained in the pretreatment step and 120 g of a 3% by weight sodium hydrogen carbonate solution were added (recycling step D2), neutralized by stirring at 80°C, and oily water was obtained. separated. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 675 g of a second organic phase and 240 g of a basic aqueous phase (washed with alkaline water). The pH of the basic aqueous phase was 8.7. Bisphenol C in the second organic phase was 32.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 81.2 mol% (32.8 [mass%] × mass of organic phase 675 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).
100 g of desalted water was added to the obtained second organic phase, and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated three times to obtain 402 g of the second water-washed aqueous phase and 672 g of the third organic phase in which bisphenol C was dissolved (second water wash). The pH of the aqueous phase after the second washing with water was 7.2. Bisphenol C in the third organic phase was 32.4% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 79.9 mol% (32.4 [mass%] × mass of organic phase 672 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

[Crystallization step C2]
It was carried out in the same manner as in Example 1, and 193 g of white bisphenol C (0.75 mol, yield based on cresol: 0.75 mol×2÷2.13 mol×100=70.4 mol %).

<Example 3>
Example 3 was carried out according to the flow shown in FIG.
[Pretreatment process]
98 g of the first water-washed aqueous phase, 240 g of the basic water phase, and 402 g of the second water-washed aqueous phase obtained in Example 2 were evaporated under reduced pressure at an oil bath temperature of 100° C. using an evaporator equipped with an oil bath. Water was distilled off to obtain 50 g of bisphenol C concentrate and 685 g of distilled water.
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1 to obtain a slurry-forming reaction liquid.

[Purification step B2]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of distilled water obtained in the pretreatment step was added to the organic phase (recycling step D2), stirred at 80° C., and then oil-water separated. After the oil-water separation, the water phase was removed from the bottom of the separable flask to obtain 625 g of the first organic phase and 98 g of the water phase after the first water washing (first water washing). The pH of the first water wash water phase was 1.1. Bisphenol C in the first organic phase was 35.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 82.1 mol% (35.8 [mass%] × mass of organic phase 625 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

To the obtained first organic phase, 50 g of the bisphenol C concentrate obtained in the pretreatment step and 120 g of a 3% by weight sodium hydrogen carbonate solution prepared by adding sodium hydrogen carbonate to the distilled water obtained in the pretreatment step were added. (recycling step D2), the mixture was stirred at 80° C. for neutralization and oil-water separation. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 630 g of a second organic phase and 241 g of a basic aqueous phase (washed with alkaline water). The pH of the basic aqueous phase was 8.3. Bisphenol C in the second organic phase was 35.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 82.7 mol% (35.8 [mass%] × mass of organic phase 630 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).
100 g of distilled water obtained in the pretreatment step was added to the obtained second organic phase (recycling step D2), and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. After repeating this operation twice, 100 g of desalted water was added and stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain 627 g of a third organic phase in which bisphenol C was dissolved and 403 g of an aqueous phase after second washing (second washing). The pH of the aqueous phase of the second water wash 4 times was 7.2. Bisphenol C in the third organic phase was 34.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 80.0 mol% (34.8 [mass%] × mass of organic phase 627 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

[Crystallization step C2]
It was carried out in the same manner as in Example 1, and white bisphenol C was 194 g (0.76 mol, yield based on cresol was 0.76 mol×2÷2.13 mol×100=71.4 mol %).
Of the 875 g of water used in the refining process, 633 g of water was recycled, giving a recycling rate of 72%.

<Example 4>
Example 4 was carried out according to the flow shown in FIG.
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1 to obtain a slurry-forming reaction liquid.

[Purification step B2]
To the slurry reaction product liquid obtained in the reaction step, 190 g of a 25% sodium hydroxide solution prepared by adding sodium hydroxide to the second water-washed aqueous phase obtained in Example 3 is added (recycling step D2) and stirred. After the temperature was raised to 75° C. to dissolve the bisphenol, the mixture was allowed to stand to separate oil and water. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of the basic aqueous phase obtained in Example 3 was added to this organic phase (recycling step D2), stirred at 80° C., and then oil-water separated. After the oil-water separation, the water phase was removed from the bottom of the separable flask to obtain 626 g of the first organic phase and 99 g of the water phase after the first water washing (first water washing). The pH of the aqueous phase after the first water wash was 2.5. Bisphenol C in the first organic phase was 35.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 82.2 mol% (35.8 [mass%] × mass of organic phase 626 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

To the obtained first organic phase, 120 g of a 3% by weight sodium hydrogen carbonate solution prepared by adding sodium hydrogen carbonate to the second water-washed aqueous phase obtained in Example 3 was added (recycling step D2). The mixture was neutralized by stirring at ℃, and oil-water separation was performed. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 624 g of a second organic phase and 239 g of a basic aqueous phase (washed with alkaline water). The pH of the basic aqueous phase was 8.8. Bisphenol C in the second organic phase was 35.2% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 80.1 mol% (35.2 [mass%] × mass of organic phase 624 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).
98 g of the first water-washed aqueous phase obtained in Example 3 was added to the obtained second organic phase (recycling step D2), and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. Then, 100 g of desalted water was added and stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated twice to obtain 619 g of a third organic phase in which bisphenol C was dissolved and 402 g of an aqueous phase after second water washing (second water washing). The pH of the 4th second water wash was 6.5. Bisphenol C in the third organic phase was 34.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 79.0 mol% (34.8 [mass%] × mass of organic phase 619 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

[Crystallization step C2]
It was carried out in the same manner as in Example 1, and white bisphenol C was 193 g (0.75 mol, yield based on cresol was 0.75 mol×2÷2.13 mol×100=70.4 mol %).
Of the 873 g of water used in the refining process, 573 g of water was recycled, giving a recycling rate of 66%.

<Comparative Example 1>
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1 to obtain a slurry-forming reaction liquid.
[Purification step B2]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of desalted water was added to the organic phase, and the mixture was stirred at 80° C. and then oil-water separated. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain 626 g of the first organic phase (first water washing). The pH of the first water wash water phase was 1.2. Bisphenol C in the first organic phase was 35.7% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 82.0 mol% (35.7 [mass%] × mass of organic phase 626 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).

120 g of a 3% by weight sodium hydrogencarbonate solution was added to the obtained first organic phase, and the mixture was neutralized by stirring at 80° C. to separate oil and water. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain 612 g of a second organic phase (washed with alkaline water). The pH of the basic aqueous phase was 8.7. Bisphenol C in the second organic phase was 34.8% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 78.1 mol% (34.8 [mass%] × mass of organic phase 612 [g]/100/molecular weight of bisphenol C (256 [g/mol])×2/substance amount of charged cresol (2.13 [mol/mol]).
100 g of desalted water was added to the obtained second organic phase, and the mixture was stirred at 80° C. to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated three times to obtain 606 g of a third organic phase in which bisphenol C was dissolved (second water washing). The pH of the 4th time of the 2nd water washing was 7.3. Bisphenol C in the third organic phase was 34.5% by weight, and the reaction yield (mol%) of bisphenol C based on cresol was 76.7 mol% (34.5 [mass%] × mass of organic phase 606 [g]÷100÷molecular weight of bisphenol C 256 [g/mol])×2÷substance amount of charged cresol 2.13 [mol mol]).

[Crystallization step C2]
It was carried out in the same manner as in Example 1, and white bisphenol C was 186 g (0.73 mol, yield based on cresol was 0.73 mol×2÷2.13 mol×100=68.5 mol %).

<Example 5>
Example 5 was carried out according to the flow shown in FIG.
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1.

[Purification step B2-1]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). To this organic phase, 99 g of the first water-washed aqueous phase obtained in Example 4 was added, and the mixture was stirred at 80° C., followed by oil-water separation. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain a first organic phase (first water wash). The pH of the first water wash water phase was 1.1.
110 g of the basic aqueous phase obtained in Example 4 was added to the obtained first organic phase (recycling step D2), and the mixture was stirred at 80° C. for neutralization and oil-water separation. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain a second organic phase (washed with alkaline water). The pH of the basic aqueous phase was 8.7.

[Crystallization step C2-1]
The second organic phase obtained in the purification step was cooled from 80°C to 20°C and maintained at 20°C to precipitate bisphenol C. Then, after cooling to 10°C and reaching 10°C, solid-liquid separation was performed using a centrifuge to obtain 206 g of crude wet cake.

[Purification step B2-2]
206 g of the crude wet cake obtained in the crystallization step C2-1 and 350 g of toluene were added to a separable flask equipped with a thermometer, a jacket and an anchor-type stirring blade, and dissolved at 75°C. After the second water washing, 100 g of the aqueous phase was added (recycling step D2) and stirred at 75°C to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. After repeating this operation again, 100 g of desalted water was added and stirred at 75° C. to separate oil and water. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain 548 g of the third organic phase (second water washing). The pH of the third water wash of the second was 7.2.

[Crystallization step C2-2]
The third organic phase obtained in the purification step B2-2 was cooled from 80°C to 20°C and maintained at 20°C to precipitate bisphenol C. Then, after cooling to 10°C and reaching 10°C, solid-liquid separation was performed using a centrifuge to obtain a wet cake.
The obtained wet cake was washed by sprinkling 300 g of toluene and subjected to solid-liquid separation using a centrifuge to obtain a purified wet cake.
Using an evaporator equipped with an oil bath, the obtained purified wet cake was distilled under reduced pressure at an oil bath temperature of 100 ° C. to remove the low-boiling components to give 180 g of white bisphenol C (0.70 mol, the cresol-based yield was 0.70 mol×2÷2.13 mmol×100=65.7 mol %).
Of the 756 g of water used in the refining process, 513 g of water was recycled, giving a recycling rate of 68%.

<Comparative Example 2>
[Reaction step A2]
It was carried out in the same manner as in Reference Example 1.
[Purification step B2-1]
190 g of a 25% sodium hydroxide solution was added to the slurry reaction product liquid obtained in the reaction step, and the mixture was stirred and heated to 75° C. to dissolve the bisphenol, and allowed to stand still for oil-water separation. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask (oil-water separation). 100 g of desalted water was added to the organic phase, and the mixture was stirred at 80° C. and then oil-water separated. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain a first organic phase (first water wash). The pH of the first water wash water phase was 1.0.
120 g of a 3% by weight sodium hydrogencarbonate solution was added to the obtained first organic phase, and the mixture was neutralized by stirring at 80° C. to separate oil and water. After oil-water separation, the basic aqueous phase was removed from the bottom of the separable flask. This operation was repeated again to obtain a second organic phase (washed with alkaline water). The pH of the basic aqueous phase was 8.6.

[Crystallization step C2-1]
The same operation as in the crystallization step 1 of Example 5 was carried out to obtain 201 g of crude wet cake. [Purification step B2-2]
Into a separable flask equipped with a thermometer, a jacket and an anchor-type stirring blade, 201 g of the crude wet cake obtained in the crystallization step 1 and 350 g of toluene were added and dissolved at 75°C. The mixture was stirred at ℃ to separate oil and water. After oil-water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated twice to obtain 545 g of the third organic phase (second water wash). The pH of the third water wash of the second was 7.2.

[Crystallization step C2-2]
The same operation as in Example 5 was carried out, and the obtained purified wet cake was subjected to distillation under reduced pressure at an oil bath temperature of 100 ° C. using an evaporator equipped with an oil bath to remove the low-boiling components, thereby obtaining white bisphenol C172 g (0.67 mol, cresol-based yield 0.67 mol×2÷2.13 mol×100=62.9 mol %).

A table summarizing the yield of bisphenol C, the yield, and the recycling rate of water in Examples and Comparative Examples is shown below. From this table, it can be seen that the yield of bisphenol C is improved by recycling the aqueous phase obtained in the purification step, and bisphenol can be produced efficiently.

<Example 6>
100.00 g (0.39 mol) of bisphenol C obtained in Example 1, 86.49 g (0.4 mol) of diphenyl carbonate and 400 mass 479 μL of ppm cesium carbonate aqueous solution was added. The reaction vessel made of glass was evacuated to about 100 Pa, and then the operation of restoring the pressure to atmospheric pressure with nitrogen was repeated three times to replace the inside of the reaction vessel with nitrogen. After that, the reactor was immersed in an oil bath at 200° C. to dissolve the contents.

The rotation speed of the stirrer was set to 100 times per minute, and the pressure in the reaction vessel was increased to absolute pressure over 40 minutes while distilling off the phenol by-product of the oligomerization reaction of bisphenol C and diphenyl carbonate in the reaction vessel. The pressure was reduced from 101.3 kPa to 13.3 kPa. Subsequently, the pressure in the reactor was maintained at 13.3 kPa, and transesterification was carried out for 80 minutes while further distilling off phenol. Thereafter, the external temperature of the reaction vessel was raised to 250° C., and the internal pressure of the reaction vessel was reduced from 13.3 kPa to 399 Pa in absolute pressure over 40 minutes to remove distilled phenol out of the system.

Thereafter, the external temperature of the reaction vessel was raised to 280° C., the absolute pressure of the reaction vessel was reduced to 30 Pa, and a polycondensation reaction was carried out. The polycondensation reaction was terminated when the agitator in the reaction tank reached a predetermined stirring power. The time from raising the temperature to 280° C. to completing the polymerization (post-stage polymerization time) was 195 minutes.
Next, the pressure in the reactor was restored to 101.3 kPa in terms of absolute pressure with nitrogen, and then the pressure was increased to 0.2 MPa in terms of gauge pressure, and the polycarbonate resin was discharged from the bottom of the reactor in the form of strands to obtain a polycarbonate resin in strands. .

After that, the strand was pelletized using a rotary cutter to obtain a polycarbonate resin in the form of pellets.
The resulting polycarbonate resin had a viscosity average molecular weight (Mv) of 24,800 and a pellet YI of 8.1. The results are summarized in Table 2.

The bisphenol produced by the method for producing bisphenol of the present invention includes resin raw materials such as polycarbonate resin, epoxy resin, and aromatic polyester resin, curing agents, color developers, anti-fading agents, and other bactericidal agents and antibacterial and antifungal agents. It is useful as an additive such as

Claims (8)

Reaction step A2 for producing bisphenol from aromatic alcohol and ketone or aldehyde;
A refining step B2 in which water is supplied to the bisphenol product obtained in the step A2 and oil-water separation is performed at 60° C. or higher and 95° C. or lower, and a slurry liquid containing bisphenol is obtained by crystallizing the oil phase obtained in the step B2. a crystallization step C2 to obtain, and a reaction step A1 of producing bisphenol from an aromatic alcohol and a ketone or aldehyde, and water is supplied to the bisphenol product obtained in the step A1, and the oil-water including a purification step B1 to separate,
A method for producing bisphenol, comprising a recycling step D2 in which the aqueous phase removed by the oil-water separation in the step B1 is supplied to the step B2 as it is or after pretreatment. 2. The method for producing bisphenol according to claim 1, wherein the aqueous phase supplied in step D2 has a pH of 7 or more and 13 or less. 3. The production of bisphenol according to claim 1 or 2, wherein step D2 concentrates the aqueous phase removed by oil-water separation, and supplies the obtained aqueous phase concentrate to the bisphenol product obtained in step A2. Method. 3. The bisphenol of claim 1 or 2, wherein step D2 extracts the bisphenol from the aqueous phase removed by oil-water separation and feeds the resulting bisphenol extract to the bisphenol product obtained in step A2. Production method. 3. The bisphenol according to claim 1 or 2, wherein the step D2 solid-liquid separates the aqueous phase removed by the oil-water separation, and supplies the resulting aqueous phase solids to the bisphenol product obtained in the step A2. manufacturing method. The purification step B1 and/or purification step B2 includes a first step in which the pH of the removed aqueous phase is acidic, a second step in which the pH of the removed aqueous phase is basic, and The method for producing bisphenol according to any one of claims 1 to 5, comprising a third step in which the pH of the phase is neutral, in this order. The bisphenol is 2,2-bis(4-hydroxy-3-methylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 1,1-bis(4-hydroxyphenyl)phenyl 7. The method for producing bisphenol according to any one of claims 1 to 6, comprising one or more selected from ethane and 1,1-bis(4-hydroxyphenyl)-3,3,5-trimethylcyclohexane. . A method for producing a polycarbonate resin, comprising a step of polymerizing a polycarbonate using the bisphenol produced by the method for producing a bisphenol according to any one of claims 1 to 7.

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