Method for producing bisphenol and method for producing polycarbonate resin

Abstract

To provide a method for producing bisphenol which is excellent in a color tone and color tone stability, and in polymerization activity.SOLUTION: A method for producing bisphenol includes the following steps A to D, wherein the step A is a step of producing bisphenol from aromatic alcohol and ketone or aldehyde, and obtaining bisphenol, the step B is a step of washing the bisphenol obtained in the step A in an oil-water separation state, and obtaining an organic phase containing bisphenol, the step C is a step of crystallizing the organic phase containing the bisphenol obtained in the step B, and obtaining a slurry liquid containing the bisphenol, and the step D is a step of solid-liquid separating the slurry liquid containing the bisphenol obtained in the step C, and obtaining a cake of the bisphenol. In the step C and / or the step D, an organic compound having an ether bond having a melting point of 40°C or lower is used.SELECTED DRAWING: None

Description

[Technical field]

[0001] The present invention relates to a method for producing a bisphenol and a method for producing a polycarbonate resin using the bisphenol. [Background technology]

[0002] Bisphenols are useful as raw materials for polymeric materials such as polycarbonate resins, epoxy resins, aromatic polyester resins, etc. Representative bisphenols include, for example, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, and bis(3,5-dimethyl-4-hydroxyphenyl)-methane (see Patent Documents 1 to 3). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2014-40376 A [Patent Document 2] JP 2020-37530 A [Patent Document 3] JP 2002-187862 A Summary of the Invention [Problem to be solved by the invention]

[0004] Bisphenols are used in a wide range of applications as raw materials for various resins such as polycarbonate resin, and their applications are expected to continue to expand in the future. In particular, bis(3,5-dimethyl-4-hydroxyphenyl)-methane (hereinafter referred to as "TMBPF") has attracted attention as a raw material monomer for polycarbonate resin with excellent flame retardancy and chemical resistance.

[0005] Polycarbonate resin, which is a typical application of bisphenol, is usually required to be colorless and transparent. Since the color tone of polycarbonate resin is greatly affected by the color tone of the raw material, it is preferable that the color tone of the raw material bisphenol is also colorless. However, some bisphenols such as TMBPF are easily colored, and known products are pale yellow crystals.

[0006] According to Patent Document 3, it is described that TMBPF is easily affected by pH and is easily colored in strongly acidic and alkaline environments. The production method of bisphenol is generally carried out under an acid catalyst, and the same is true for TMBPF. In order to increase the reaction rate and produce bisphenol with a high yield, it is preferable to use a strongly acidic catalyst. Therefore, it is easy to predict that bisphenol will become colored during the reaction to produce TMBPF.

[0007] According to Patent Document 2, it is described that bisphenol having excellent polymerization activity can be obtained by adjusting the pH of the aqueous phase separated from the organic phase containing bisphenol to 8.5 or more. However, when TMBPF was produced by the method described in Example 1, the produced TMBPF was dissolved in acetone, and the color of the solution was observed. It was found that the solution was significantly colored and the color tone further deteriorated over time. The deterioration of the color tone over time is considered to be due to the generation and increase of colored components. In that case, it is synonymous with the purity of the produced TMBPF being reduced, and the reduction in the purity of TMBPF is not preferable for obtaining a polycarbonate resin with a desired molecular weight.

[0008] Therefore, there is a demand for the development of a production method capable of efficiently producing bisphenol having excellent color tone, color stability, and polymerization activity. The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a method for producing bisphenol which is excellent in color tone, color tone stability and polymerization activity, and a method for producing polycarbonate resin which is excellent in color tone by using bisphenol obtained by the above-mentioned bisphenol production method. [Means for solving the problem]

[0009] Means for Solving the Problems The present inventors have conducted intensive research to solve the above problems and have found that by using an organic compound having an ether bond for crystallization or for washing a bisphenol wet cake, it is possible to selectively remove colored components and produce bisphenol having excellent color tone, thereby completing the present invention.

[0010] That is, the present invention relates to the following inventions. [1] A method for producing bisphenol comprising the following steps A to D: Step A: A step of producing bisphenol from an aromatic alcohol and a ketone or aldehyde to obtain bisphenol Step B: A step of washing the bisphenol obtained in step A with water while separating oil and water, thereby obtaining an organic phase containing bisphenol. Step C: A step of crystallizing the organic phase containing bisphenol obtained in step B to obtain a slurry liquid containing bisphenol. Step D: A step of subjecting the bisphenol-containing slurry obtained in step C to solid-liquid separation to obtain a bisphenol cake. A method for producing bisphenol, wherein in the step C and / or the step D, an organic compound having an ether bond and a melting point of 40° C. or lower is used. [2] The method for producing bisphenol according to [1], further comprising a step of neutralizing the aqueous phase obtained after oil-water separation so that the pH of the aqueous phase obtained in step B is 8 or more and 13 or less. [3] The method for producing bisphenol according to [1] or [2], wherein the step A is carried out in the presence of an acid catalyst. [4] The method for producing bisphenol according to any one of [1] to [3], wherein the organic compound having an ether bond is a compound represented by the following general formula (4): [ka] (In formula (4), R 11 and R 12are each independently any one selected from the group consisting of an alkyl group, an alkylene group, an alkenyl group, and an aryl group; R 11 and R 12 and may be crosslinked.) [5] The method for producing bisphenol according to any one of [1] to [4], wherein the bisphenol is any one selected from the group consisting of bis(4-hydroxy-2,6-dimethylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-2-methylphenyl)propane, and 9,9-bis(4-hydroxyphenyl)fluorene. [6] A method for producing a polycarbonate, comprising a step of polymerizing the bisphenol produced by the method for producing bisphenol according to any one of [1] to [5]. Effect of the Invention

[0011] According to the present invention, a method for producing bisphenol excellent in color tone, color tone stability, and polymerization activity is provided. In a preferred embodiment of the present invention, the amount of colored components can be reduced. Furthermore, the bisphenol produced by the method for producing bisphenol can be used to efficiently produce polyphenol. Recarbonate resin can be produced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] The following describes the embodiments of the present invention in detail, but the following description of the constituent elements is one example (representative example) of the embodiment of the present invention, and the present invention is not limited to the following content as long as the gist of the present invention is not changed. Note that when the expression "~" is used in this specification, it is used as an expression including the numerical values ​​or physical property values ​​before and after it.

[0013] <1. Manufacturing method of bisphenol> One embodiment of the present invention relates to a method for producing bisphenol, which produces bisphenol by a condensation reaction (hereinafter, sometimes simply referred to as "reaction") between an aromatic alcohol and a ketone or an aldehyde in the presence of an acidic catalyst.

[0014] The present inventors have found that washing the aqueous phase separated from the organic phase containing bisphenol until the pH of the aqueous phase becomes 8.5 or higher deteriorates the color of the bisphenol and generates colored components over time. They have also found that using an organic compound having an ether bond in the crystallization and / or wet cake washing process removes the colored components and produces bisphenol with little change in color over time.

[0015] One embodiment of the present invention is a method for producing bisphenol, including the following steps A to D, in which an organic compound having an ether bond and a melting point of 40° C. or lower is supplied in step C and / or step D. Step A: A step of producing bisphenol from an aromatic alcohol and a ketone or aldehyde to obtain bisphenol Step B: A step of washing the bisphenol obtained in step A with water while separating oil and water, thereby obtaining an organic phase containing bisphenol. Step C: A step of crystallizing the organic phase containing bisphenol obtained in step B to obtain a slurry liquid containing bisphenol. Step D: A step of subjecting the bisphenol-containing slurry obtained in step C to solid-liquid separation to obtain a bisphenol cake.

[0016] [Bisphenol] The bisphenol produced is usually a compound represented by the following general formula (1). [ka]

[0017] R 1 ~R 4 are each independently selected from a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and an amino group. The alkyl group, alkoxy group, aryl group, and the like may be substituted or unsubstituted. The alkyl group and alkoxy group may be linear, branched, or cyclic. R 1 ~R 4Specific examples of the aryl group include a hydrogen atom, a fluoro group, a chloro group, a bromo group, an iodo group, a methyl group, an ethyl group, a n-propyl group, an i-propyl group, a n-butyl group, an i-butyl group, a t-butyl group, a n-pentyl group, an i-pentyl group, a n-hexyl group, a n-heptyl group, a n-octyl group, a n-nonyl group, a n-decyl group, a n-undecyl group, a n-dodecyl group, a methoxy group, an ethoxy group, a n-propoxy group, an i-propoxy group, a n-butoxy group, an i-butoxy group, a t-butoxy group, a n-pentyloxy group, an i-pentyloxy group, a Examples of such groups include an n-hexyloxy group, an n-heptyloxy group, an n-octyloxy group, an n-nonyloxy group, an n-decyloxy group, an n-undecyloxy group, an n-dodecyloxy group, a cyclopropyl group, a cyclobutyl group, a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a cyclododecyl group, a benzyl group, a phenyl group, a tolyl group, a 2,6-dimethylphenyl group, an amino group, a methylamino group, a dimethylamino group, a diethylamino group, and a phenylamino group. Of these, R 2 and R 3 is preferably a hydrogen atom, since if it is sterically bulky, the condensation reaction does not proceed easily.

[0018] R 5 and R 6are each independently selected from a hydrogen atom, an alkyl group, an alkoxy group, and an aryl group. The alkyl group, alkoxy group, and aryl group may be substituted or unsubstituted. For example, a hydrogen atom, a methyl group, an ethyl group, an n-propyl group, an i-propyl group, an n-butyl group, an i-butyl group, a t-butyl group, an n-pentyl group, an i-pentyl group, an n-hexyl group, an n-heptyl group, an n-octyl group, a 2-ethylhexyl group, an n-nonyl group, an n-decyl group, an n-undecyl group, an n-dodecyl group, a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group, a t-butoxy group, an n-pentyl group, an i ... Examples of such aryloxy groups include butyloxy, isobutyloxy, n-hexyloxy, n-heptyloxy, n-octyloxy, n-nonyloxy, n-decyloxy, n-undecyloxy, n-dodecyloxy, cyclopropyl, cyclobutyl, cyclopentyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclododecyl, benzyl, phenyl, tolyl, and 2,6-dimethylphenyl groups.

[0019] Specifically, bis(4-hydroxyphenyl)methane, bis(4-hydroxy-3-methylphenyl)methane, bis(4-hydroxy-3,5-dimethylphenyl)methane, bis(4-hydroxyphenyl)ethane, bis(4-hydroxy-3-methylphenyl)ethane, bis(4-hydroxy-3,5-dimethylphenyl)ethane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxy-3-methylphenyl)propane, 2,2-bis(4-hydroxy-3,5-dimethylphenyl)propane, 1,1-bis(4-hydroxy-3-methylphenyl)cyclohexane, 9,9-bis(4-hydroxy-3-methylphenyl)fluorene, Examples of the 4-hydroxyphenyl ether include, but are not limited to, 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, and 4,4-bis(4-hydroxy-3-methylphenyl)heptane.

[0020] Among these, the preferred bisphenol is any one selected from the group consisting of bis(4-hydroxy-3,5-dimethylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-2-methylphenyl)propane, and 9,9-bis(4-hydroxyphenyl)fluorene.

[0021] [Aromatic alcohols] The aromatic alcohol is usually a compound represented by the following general formula (2). [ka] In the general formula (2), R 1 ~R 4is R in the above general formula (1). 1 ~R 4 It is synonymous with that in.

[0022] R 2 and R 3 is preferably a hydrogen atom since the condensation reaction is difficult to proceed if it is sterically bulky. 1 ~R 4 are each independently preferably a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, or an amino group, and more preferably a hydrogen atom or an alkyl group. 1 and R 4 are each independently a hydrogen atom or an alkyl group, and R 2 and R 3 is a hydrogen atom. The alkyl group may be an alkyl group having 1 to 12 carbon atoms or an alkyl group having 1 to 6 carbon atoms.

[0023] Specifically, examples of the compound represented by the above general formula (2) include phenol, methylphenol (cresol), dimethylphenol (xylenol), ethylphenol, propylphenol, butylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, aminophenol, benzylphenyl, phenylphenol, etc. Among these, any one selected from the group consisting of phenol, methylphenol, and dimethylphenol is preferred, methylphenol or dimethylphenol is more preferred, and methylphenol is even more preferred.

[0024] [Ketone or aldehyde] The ketone or aldehyde is usually a compound represented by the following general formula (3). [ka] In the general formula (3), R 5 , R 6 is R in the above general formula (1). 5 , R 6It is synonymous with that in.

[0025] Preferably, R 5 and R 6 are each independently a hydrogen atom, an alkyl group, an aryl group, or R 5 and R 6 and the adjacent carbon atoms are bonded together to form a cycloalkylidene group. The alkyl group may be an alkyl group having 1 to 12 carbon atoms, or an alkyl group having 1 to 6 carbon atoms. For example, R 5 and R 6 are each independently an alkyl group or R 5 and R 6 and are bonded together with adjacent carbon atoms to form a cycloalkylidene group.

[0026] Specific examples of the compound represented by the general formula (3) include aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentanaldehyde, hexanealdehyde, heptanealdehyde, octanaldehyde, nonanealdehyde, decanaldehyde, undecanealdehyde, and dodecanealdehyde; ketones such as acetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, decanone, undecanone, and dodecanone; benzaldehyde, furanaldehyde, and the like. aryl alkyl ketones such as phenyl methyl ketone, phenyl ethyl ketone, phenyl propyl ketone, cresyl methyl ketone, cresyl ethyl ketone, cresyl propyl ketone, xylyl methyl ketone, xylyl ethyl ketone, and xylyl propyl ketone; and cyclic alkane ketones such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, and cyclododecanone.

[0027] When the amount of ketone or aldehyde is large relative to the aromatic alcohol as a raw material, the ketone or aldehyde is easily polymerized, and when the amount is small, the aromatic alcohol is lost unreacted. 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 1.5 or more, more preferably 1.6 or more, and even more preferably 1.7 or more. The upper limit is preferably 15 or less, more preferably 10 or less, and even more preferably 8 or less.

[0028] [Acidic catalyst] In the method for producing bisphenol, the acid catalyst is preferably a strong acid compound such as hydrogen chloride gas, hydrochloric acid, sulfuric acid, phosphoric acid, aromatic sulfonic acid such as p-toluenesulfonic acid, and aliphatic sulfonic acid such as methanesulfonic acid, from the viewpoint of excellent reaction efficiency. From the viewpoint of no volatility of the catalyst and less burden on the equipment, it is more preferable to use sulfuric acid, phosphoric acid, aromatic sulfonic acid, and aliphatic sulfonic acid.

[0029] If the molar ratio of the acid catalyst used in the condensation reaction to the aromatic alcohol as a raw material (moles of acid catalyst / moles of aromatic alcohol) is low, the sulfuric acid is diluted with the by-produced water as the condensation reaction proceeds, and the reaction takes time. If the molar ratio is high, the generated bisphenol may be decomposed. For these reasons, the molar ratio of the acid catalyst used in the condensation reaction to the aromatic alcohol as a raw material is preferably 0.01 or more, more preferably 0.02 or more, and even more preferably 0.03 or more. The upper limit is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less.

[0030] [Thiol cocatalyst] In the reaction of condensing aromatic alcohol with ketone or aldehyde, a thiol promoter can be used as a promoter. Examples of the thiol promoter include mercaptocarboxylic acids such as mercaptoacetic acid, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 4-mercaptobutyric acid, methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, 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, and mercaptophenol.

[0031] If the molar ratio of the thiol promoter to the ketone or aldehyde ((moles of thiol promoter / moles of ketone) or (moles of thiol promoter / moles of aldehyde)) is low, the effect of improving the selectivity of bisphenol by using the thiol promoter cannot be obtained, and if it is high, the thiol promoter may be mixed into the bisphenol, resulting in a deterioration in quality. For these reasons, the lower limit of the molar ratio of the thiol promoter to the ketone or aldehyde is preferably 0.001 or more, more preferably 0.005 or more, and even more preferably 0.01 or more. The upper limit is preferably 1 or less, more preferably 0.5 or less, and even more preferably 0.1 or less.

[0032] [Reaction solvent] The condensation reaction of the aromatic alcohol with the ketone or aldehyde may be carried out in the presence of a solvent. Examples of the solvent include water, aromatic hydrocarbons, aliphatic alcohols, and aliphatic hydrocarbons. These solvents may be used alone or in any combination and ratio of two or more.

[0033] Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene.

[0034] Examples of the aliphatic hydrocarbon include hexane, heptane, octane, nonane, decane, undecane, and dodecane.

[0035] Examples of aliphatic alcohols include monohydric alkyl alcohols such as methanol, ethanol, n-propanol, i-propanol, n-butanol, i-butanol, t-butanol, n-pentanol, i-pentanol, n-hexanol, n-heptanol, 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 monohydric alkyl alcohol having 1 to 12 carbon atoms, and more preferably a monohydric alkyl alcohol having 1 to 8 carbon atoms.

[0036] In addition, a large amount of the aromatic alcohol, which is the raw material, may be used in place of the organic solvent. In this case, the unreacted aromatic alcohol is lost, but the loss can be reduced by recovering and purifying it by distillation or the like and reusing it.

[0037] When a solvent is used, if the mass ratio of the solvent to the raw material ketone or aldehyde (solvent mass / ketone or aldehyde mass) is too high, the ketone or aldehyde and the aromatic alcohol do not react easily, and the reaction takes a long time. If the mass ratio is too low, the resulting bisphenol may cause poor mixing or may promote the polymerization of the ketone or aldehyde. For these reasons, the mass ratio of the solvent to the ketone or aldehyde is preferably 0.5 or more, more preferably 1 or more. The upper limit may be adjusted within a range in which precipitation of the bisphenol occurs depending on the type of solvent, and may be 50 or less, or 30 or less.

[0038] By carrying out the reaction while precipitating the produced bisphenol, side reactions can be suppressed, and bisphenol can be produced with good selectivity. Therefore, when a solvent is used in the reaction, it is preferable to use a solvent in which bisphenol is low in solubility. Examples of solvents in which bisphenol is low in solubility include water and aromatic hydrocarbons. For this reason, the solvent preferably contains water and / or aromatic hydrocarbons as the main component, and the solvent preferably contains 55% by mass or more of water and / or aromatic hydrocarbons, more preferably 70% by mass or more, and even more preferably 80% by mass or more of water and / or aromatic hydrocarbons.

[0039] [Reaction conditions] As described above, in the method for producing bisphenol according to the present embodiment, as the condensation reaction proceeds, precipitation of bisphenol occurs, so that the reaction liquid changes to a slurry liquid, and the condensation reaction is carried out in a slurry state. A slurry liquid is a suspension in which a solid is dispersed in a liquid. Specifically, the slurry liquid is a three-phase slurry liquid in which solid bisphenol is dispersed in a liquid containing an organic phase (unreacted aromatic alcohol, ketone, aldehyde, etc.) and an aqueous phase (acid catalyst, generated water, etc.).

[0040] The smaller the amount of bisphenol precipitated, the more the decomposition products of bisphenol tend to increase. Therefore, it is preferable to precipitate a certain amount or more of bisphenol in the slurry liquid by appropriately selecting the presence or absence of an organic solvent, the reaction time, the reaction temperature, and the like. For example, the slurry concentration of the slurry liquid at the end of the reaction (mass of solid bisphenol / mass of slurry liquid×100(%)) can be 15 mass% or more or 20 mass% or more. The slurry concentration of the slurry liquid at the end of the reaction may be controlled by setting an upper limit such as 50 mass% or less, 40 mass% or less, or 35 mass% or less.

[0041] If the reaction temperature of the condensation reaction is too low, the condensation reaction does not proceed easily, so the reaction temperature is preferably −30° C. or higher, more preferably −20° C. or higher, and even more preferably −15° C. or higher. If the reaction temperature is too high, a side reaction, a self-condensation reaction of ketone or aldehyde, proceeds, and when a thiol is used as a co-catalyst, oxidative decomposition of the thiol tends to proceed, so the reaction temperature is preferably 100° C. or lower, more preferably 95° C. or lower, and even more preferably 90° C. or lower.

[0042] The reaction time of the condensation reaction is adjusted appropriately depending on the reaction conditions such as the type of bisphenol to be produced, the reaction temperature, and the production scale, but is usually 500 hours or less, and may be 400 hours or less or 350 hours or less. If the reaction time is too long, the produced bisphenol will decompose, so the reaction time is preferably 30 hours or less, more preferably 25 hours or less, and even more preferably 20 hours or less. The lower limit of the reaction time is usually 0.5 hours or more, preferably 1 hour or more, and more preferably 1.5 hours or more. The condensation reaction can be terminated, for example, by adding water or a base in an amount equal to or greater than the amount of the acid catalyst used to reduce the concentration of the acid catalyst.

[0043] [Reaction Apparatus] 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 vessel is made of a corrosion-resistant material. In particular, it is preferable to use a reaction vessel made of glass lining, which has excellent corrosion resistance.

[0044] [Cleaning process (process B)] To produce bisphenol having excellent polymerization activity, it is necessary to neutralize and remove the acid catalyst used in the reaction for producing bisphenol. Specifically, an organic phase containing bisphenol is mixed with demineralized water or a basic aqueous solution, and then separated into an organic phase and an aqueous phase, and the aqueous phase is removed to obtain an organic phase. The organic phase is repeatedly washed with demineralized water and / or a basic aqueous solution until the pH of the removed aqueous phase becomes basic from 8.0 to 13.0. Examples of basic aqueous solutions include aqueous solutions in which a basic substance such as sodium hydroxide or sodium bicarbonate is dissolved. When washing is performed multiple times, the same basic aqueous solution or different basic aqueous solutions may be used. The temperature for measuring the pH of the aqueous phase is preferably room temperature (20 to 30°C), for example, 25°C.

[0045] When the organic phase containing bisphenol is washed with water, the end point of the washing can be controlled by the electrical conductivity of the aqueous phase that is removed. If metal salts derived from the catalyst remain in the organic phase containing bisphenol, they cause a deterioration in color tone, so the electrical conductivity of the aqueous phase after washing is preferably 100 μS / cm or less, more preferably 50 μS / cm or less, and even more preferably 10 μS / cm or less. The temperature for measuring the electrical conductivity of the aqueous phase is preferably room temperature (20 to 30°C), for example, 25°C.

[0046] [Purification process (process C)] The organic phase containing bisphenol is cooled to obtain bisphenol of the desired purity. It is preferable to crystallize the bisphenol. In this case, the solvent of the bisphenol precipitation solution is not particularly limited as long as the raw material bisphenol is dissolved therein, and usually, the organic solvent is the main component (for example, 90% by mass or more or 95% by mass or more). As the organic solvent, the same solvent as described above can be used.

[0047] The amount of solvent relative to the amount of bisphenol is not particularly limited, but if the amount is excessive relative to the amount of bisphenol, the amount of bisphenol dissolved in the solvent increases, resulting in a loss of bisphenol. If the amount is too small, the precipitated bisphenol may not be mixed well, inhibiting crystal growth. Therefore, the amount of solvent relative to bisphenol (weight ratio) is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1.0 or more, and is preferably 10 or less, more preferably 8 or less, and most preferably 5 or less.

[0048] The crystallization may be carried out multiple times depending on the purity of the desired bisphenol, but since some of the bisphenol dissolves in the mother liquor during the crystallization and is lost, the crystallization is preferably carried out five times or less, more preferably three times or less.

[0049] [Solid-liquid separation (process D)] The precipitated bisphenol is then subjected to solid-liquid separation and dried. The method of solid-liquid separation is not particularly limited, and a conventional method such as filtration, centrifugation, decantation, etc. can be used, but it is preferable to wash the bisphenol wet cake with an organic solvent, desalted water, and an aqueous solution of an inorganic salt according to the purity of the target bisphenol. A suspension washing method in which a washing solvent is supplied to the bisphenol wet cake to make a slurry liquid and then solid-liquid separation is performed, and a shake-off washing method in which a washing solvent is sprinkled while performing solid-liquid separation are generally used.

[0050] [Removal of coloring components] The coloring components contained in bisphenol can be efficiently removed by an organic compound having an ether bond and a melting point of 40° C. or less. The organic compound having an ether bond is preferably used in the step of purifying bisphenol (step C and / or step D above). Specifically, it is preferably used as a crystallization solvent, and also preferably used as a washing solvent for suspending and spraying a bisphenol wet cake.

[0051] The organic compound having an ether bond and a melting point of 40° C. or less is preferably an organic compound represented by the following formula (4). [ka] In formula (4), R 11 and R 12 are each independently any one selected from the group consisting of an alkyl group, an alkylene group, an alkenyl group, and an aryl group; R 11 and R 12 Specific examples of the compound include aliphatic ethers such as dimethyl ether, diethyl ether, dibutyl ether, and ethyl methyl ether, aromatic ethers such as methyl phenyl ether, ethyl phenyl ether, and diphenyl ether, and cyclic ethers such as tetrahydrofuran, methyltetrahydropyran, furan, and benzofuran.

[0052] When used as a crystallization solvent, it is preferable to select an organic compound having an ether bond and a boiling point higher than the operating temperature. In order to dissolve bisphenol, it can be used in combination with an organic solvent, or it may be used in combination with multiple organic solvents. In addition, water may be provided before crystallization. In the case of feeding, phase separation and washing, it is preferable to select an organic compound having an ether bond, which is difficult to dissolve in water and easy to separate into phases.

[0053] When used as a crystallization solvent, the organic compound having an ether bond may be used in combination with the above-mentioned solvent, or the organic compound having an ether bond may be used alone or in combination of a plurality of organic compounds having an ether bond. When mixed with the above-mentioned crystallization solvent, if the amount of the organic compound having an ether bond to the bisphenol is too small, the efficiency of removing the coloring components tends to deteriorate, so the amount (weight ratio) of the organic compound having an ether bond to the amount of bisphenol is preferably 0.1 or more, more preferably 0.2 or more, and even more preferably 0.3 or more.

[0054] There is no particular limitation on the organic compound having an ether bond when it is supplied to the suspension washing and the spray washing. The organic compound having an ether bond may be used alone or in combination with an organic solvent.

[0055] If the amount of the organic compound having an ether bond relative to the amount of the bisphenol wet cake is small, the coloring components may not be removed efficiently. If the amount is large, the amount of bisphenol dissolved in the organic compound having an ether bond tends to increase, resulting in loss, which may be uneconomical. Therefore, the amount (weight ratio) of the organic compound having an ether bond relative to the amount of the bisphenol wet cake is preferably 0.5 or more, more preferably 0.8 or more, even more preferably 1.0 or more, and preferably 10 or less, more preferably 8 or less, and most preferably 5 or less.

[0056] [Uses of bisphenol] The obtained bisphenol can be used as a constituent, curing agent, additive, or precursor thereof for various thermoplastic resins such as polyether resins, polyester resins, polyarylate resins, polycarbonate resins, polyurethane resins, and acrylic resins, and various thermosetting resins such as epoxy resins, unsaturated polyester resins, phenolic resins, polybenzoxazine resins, and cyanate resins, which are used for various applications such as optical materials, recording materials, insulating materials, transparent materials, electronic materials, adhesive materials, and heat-resistant materials. It is also useful as an additive for color developers, anti-fading agents, bactericides, and antibacterial and antifungal agents for heat-sensitive recording materials, etc.

[0057] Among these, it is preferable to use it as a raw material (monomer) of thermoplastic resins and thermosetting resins because it can impart good mechanical properties, and more preferably as a raw material of polycarbonate resins and epoxy resins. It is also preferable to use it as a color developer, and more preferably to use it in combination with a leuco dye and a discoloration temperature regulator.

[0058] <2. Manufacturing method of 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, for example, a method of subjecting bisphenol and a carbonate diester such as diphenyl carbonate to an ester exchange reaction in the presence of an alkali metal compound and / or an alkaline earth metal compound. The ester exchange reaction can be carried out by appropriately selecting a known method, but an example using bisphenol and diphenyl carbonate as raw materials will be described below.

[0059] 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 in terms of the amount of terminal hydroxyl groups in the produced polycarbonate resin and excellent thermal stability of the polymer, and is preferably small in terms of the rate of transesterification reaction being fast and easy production of a polycarbonate resin with a desired molecular weight. For these reasons, the amount of diphenyl carbonate used relative to 1 mole of bisphenol is usually 1.001 moles or more, preferably 1.002 moles or more, and usually 1.3 moles or less, preferably 1.2 moles or less.

[0060] As for the method of supplying the raw materials, the bisphenol and diphenyl carbonate of the present invention can be supplied in a solid state, but it is preferable to melt one or both of them and supply them in a liquid state.

[0061] When producing a polycarbonate resin by the transesterification reaction of diphenyl carbonate and bisphenol, a transesterification catalyst is usually used. As the transesterification catalyst, it is preferable to use an alkali metal compound and / or an alkaline earth metal compound. These may be used alone or in any combination and ratio of two or more. For practical purposes, it is desirable to use an alkali metal compound.

[0062] The amount of catalyst used per mole 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 50 μmol or less, more preferably 20 μmol or less.

[0063] When the amount of the catalyst used is within the above range, it is easy to obtain the polymerization activity required for producing a polycarbonate resin having a desired molecular weight, and it is easy to obtain a polycarbonate resin that has excellent polymer color, does not undergo excessive polymer branching, and has excellent fluidity during molding.

[0064] In producing a polycarbonate resin by the above method, it is preferred to continuously feed both of the above raw materials to a raw material mixing tank, and then continuously feed the resulting mixture and the transesterification catalyst to a polymerization tank. In the production of polycarbonate resins by the transesterification method, usually, both raw materials are fed into a raw material mixing tank, stirred uniformly, and then fed into a polymerization tank to which a catalyst is added, thereby producing a polymer. EXAMPLES

[0065] The present invention will be described in more detail below with reference to examples and comparative examples. However, the present invention is not limited to the following examples as long as it does not depart from the gist of the present invention.

[0066] [Raw materials and reagents] The following reagents were used: 2,6-xylenol, o-cresol, 37% formaldehyde aqueous solution, acetone, p-toluenesulfonic acid monohydrate, sulfuric acid, dodecanethiol, sodium hydrogen carbonate, methanol, toluene, methyltetrahydropyran, diethyl ether, tetrahydrofuran, diisopropyl ether, and cesium carbonate, all of which were manufactured by Wako Pure Chemical Industries, Ltd. Diphenyl carbonate used was a product manufactured by Mitsubishi Chemical Corporation. As for TMBPF, a reagent manufactured by Tokyo Chemical Industry Co., Ltd. was used.

[0067] (pH Measurement) The pH was measured using a pH meter "pH METERES-73" manufactured by Horiba, Ltd., for the aqueous phase at 25°C taken out of the flask.

[0068] (Electrical Conductivity) The electrical conductivity was measured using a conductivity meter "COND METER D-71" manufactured by Horiba, Ltd., for the aqueous phase at 25°C taken out of the flask.

[0069] (Evaluation of bisphenol polymerization activity) A polycarbonate resin was produced using the bisphenol composition, and the time from raising the temperature to 280° C. to the end of polymerization (second-stage polymerization time) was evaluated as the polymerization activity of bisphenol. The polymerization activity of bisphenol was evaluated based on the following criteria. ○: 140 minutes or more and 200 minutes or less △: Less than 140 minutes or more than 200 minutes ×: Polymerization reaction does not proceed

[0070] (Viscosity average molecular weight (Mv)) The viscosity average molecular weight (Mv) was determined by dissolving the polycarbonate resin in methylene chloride (concentration: 6.0 g / L), measuring the specific viscosity (ηsp) at 20° C. using an Ubbelohde viscometer, and calculating the viscosity average molecular weight (Mv) using the following formula. ηsp / C=[η](1+0.28ηsp) [η]=1.23×10 -4 Mv 0.83

[0071] (Pellet YI) Pellet YI (transparency of polycarbonate resin) was evaluated by measuring the YI value (yellowness index value) of polycarbonate resin pellets in reflected light in accordance with ASTM D1925. Equipment: Konica Minolta CM-5 spectrophotometer Measurement conditions: A measurement diameter of 30 mm and SCE were selected. A petri dish calibration glass CM-A212 was fitted into the measurement section, and a zero calibration box CM-A124 was placed over it to perform zero calibration, followed by white calibration using the built-in white calibration plate. Measurements were then performed using the white calibration plate CM-A210, and it was confirmed that L* was 99.40±0.05, a* was 0.03±0.01, b* was -0.43±0.01, and YI was -0.58±0.01. The pellets were measured by filling a cylindrical glass container with an inner diameter of 30 mm and a height of 50 mm with pellets to a depth of about 40 mm. The pellets were removed from the glass container and the measurement was repeated twice, and the average value of the three measurements was used.

[0072] <Reference example> Bisphenol C was synthesized with reference to Example 1 of JP 2020-037530 A. In a separable flask equipped with a thermometer, a dropping funnel, a jacket, and an anchor-type stirring blade, 320 g of toluene, 12 g of methanol, and 230 g (2.13 mol) of ortho-cresol were placed under a nitrogen atmosphere, and the internal temperature was adjusted to 10° C. or less. Then, 95 g of 98% by mass sulfuric acid was slowly added over 0.3 hours while stirring, and the mixture was cooled to 5° C. or less to obtain a first mixed liquid.

[0073] A second mixed liquid (dropping liquid) was prepared by mixing 50 g of toluene, 65 g (1.12 mol) of acetone, and 5.4 g of dodecanethiol in a 500 mL Erlenmeyer flask.

[0074] After the internal temperature of the first mixed liquid was reduced to 5°C or less, the second mixed liquid was fed using the dropping funnel over 1 hour so that the internal temperature did not exceed 10°C, and the prepared reaction liquid was stirred for 2.5 hours at an internal temperature of 10°C. Then, 190g of 25% by mass aqueous sodium hydroxide solution was fed and the temperature was raised to 80°C. After reaching 80°C, the mixture was allowed to stand and the lower aqueous phase was extracted. 400g of demineralized water was added to the obtained first organic phase, mixed and allowed to stand for 30 minutes, and the aqueous phase was removed. 120g of 1.5% by mass sodium bicarbonate solution was added to the obtained second organic phase, mixed and allowed to stand for 30 minutes, and the lower layer was extracted. 120g of 1.5% by mass sodium bicarbonate solution was further added to the obtained third organic phase, mixed and allowed to stand for 30 minutes, and the lower layer was extracted. The resulting fourth organic phase was cooled from 80°C to 20°C and maintained at 20°C to precipitate bisphenol C. It was then cooled to 10°C and centrifuged using a centrifuge. Solid-liquid separation was carried out to obtain a wet cake.

[0075] The entire amount of the wet cake and 370 g of toluene were placed in a full jacket type 1 liter separable flask equipped with a thermometer and a stirrer, and the temperature was raised to 80°C. It was confirmed that the solution was homogeneous, and a fifth organic phase (organic phase (O1)) was obtained. 200 g of desalted water was added to the obtained fifth organic phase (O1), mixed for 30 minutes, allowed to stand, and the lower aqueous phase (first aqueous phase (W1)) was removed. The pH of the first aqueous phase (W1) was 9.3. 200 g of desalted water was added to the sixth organic phase (organic phase (O2)) obtained by removing the first aqueous phase (W1), mixed for 30 minutes, allowed to stand, and the lower aqueous phase (second aqueous phase) was removed. 200 g of desalted water was added to the seventh organic phase obtained by removing the lower layer, mixed for 30 minutes, allowed to stand, and the lower aqueous phase (third aqueous phase (W2)) was removed. The electrical conductivity of the third aqueous phase (W2) was 2.1 μS / cm.

[0076] The eighth organic phase (O3) obtained by removing the third aqueous phase (W2) was cooled from 80°C to 10°C to precipitate bisphenol C. Then, filtration was performed using a centrifuge (3000 rpm for 10 minutes) to obtain wet purified bisphenol C. Using an evaporator equipped with an oil bath, low boiling fractions were distilled off under reduced pressure at an oil bath temperature of 100°C to obtain 190 g of white bisphenol C. This operation was repeated to obtain 380 g of bisphenol C.

[0077] <Example 1> [Reaction process] In a 1L separable flask equipped with a thermometer, dropping funnel, jacket, and anchor-type stirring blade, 138g of 2,6-xylenol, 90g of 37% formaldehyde aqueous solution, 21.6g of p-toluenesulfonic acid monohydrate, and 400g of demineralized water were placed under a nitrogen atmosphere, and the internal temperature was gradually raised to 80°C while stirring, and the mixture was stirred for 4 hours while maintaining the temperature at 80°C to obtain a reaction solution of TMBPF. Crystals of TMBPF were precipitated in the reaction solution. The resulting reaction solution of TMBPF was suction filtered to obtain 203g of crude cake of TMBPF.

[0078] [Cleaning process] The crude cake of TMBPF obtained in the reaction step was placed in a separable flask again, and 200 g of toluene, 120 g of methyltetrahydropyran, and 100 g of desalted water were added, and the mixture was heated to 75°C and then allowed to stand to separate into oil and water. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask, and an organic phase O1 containing TMBPF was obtained. The obtained organic phase O1 containing TMBPF was neutralized by adding 3 wt% sodium bicarbonate solution and stirring to separate the oil and water. After the oil-water separation, the aqueous phase was removed from the bottom of the separable flask to obtain an organic phase O2 containing TMBPF. At this time, the pH of the removed aqueous phase was 9.2. This operation was repeated again to obtain an organic phase O3 containing TMBPF. 100 g of demineralized water was added to the organic phase O3 containing TMBPF, and the mixture was stirred and allowed to stand to separate the oil and water. After the oil and water separation, the aqueous phase was removed from the bottom of the separable flask. This operation was repeated, and the organic phase O3 was washed until the electrical conductivity of the removed aqueous phase reached 5.0 μS / cm. The resulting organic phase was designated organic phase O4.

[0079] [Refining process] The organic phase O4 containing TMBPF obtained in the washing process was gradually cooled from 75°C to 5°C to precipitate TMBPF crystals. The obtained liquid containing TMBPF crystals was subjected to solid-liquid separation using a centrifuge to obtain a refined cake of TMBPF. The obtained refined cake of TMBPF was subjected to distillation of low boiling fractions at an oil bath temperature of 100°C under reduced pressure using an evaporator equipped with an oil bath, thereby obtaining white TMBPF.

[0080] [Color evaluation] 4 g of the obtained TMBPF was weighed out into a test tube, and 16 g of acetone was added to dissolve the TMBPF. The Hazen color number was then measured with a colorimeter. The Hazen color number immediately after dissolution was 0, and 30 minutes after dissolution, the Hazen color number was 5.

[0081] [Polycarbonate resin color tone] In a 150 mL glass reaction vessel equipped with a stirrer and a distillation tube, 80.0 g (0.31 mol) of the obtained TMBPF, 20.0 g (0.08 mol) of BPC produced in the reference example, 88.2 g (0.41 mol) of diphenyl carbonate, and 890 μL of a 1000 ppm by mass cesium carbonate aqueous solution were placed. The glass reaction vessel was depressurized to about 100 Pa, and then the operation of returning the pressure to atmospheric pressure with nitrogen was repeated three times to replace the inside of the reaction vessel with nitrogen. Then, the reaction vessel was immersed in an oil bath at 200° C. to melt the contents.

[0082] The stirrer was rotated at 100 revolutions per minute, and the pressure in the reaction vessel was reduced from 101.3 kPa to 13.3 kPa in absolute pressure over 40 minutes while distilling off phenol by-produced in the oligomerization reaction of TMBPF and BPC with diphenyl carbonate in the reaction vessel. The pressure in the reaction vessel was then maintained at 13.3 kPa, and the transesterification reaction was carried out for 80 minutes while further distilling off phenol. Thereafter, the temperature outside the reaction vessel was raised to 250°C, and the pressure in the reaction vessel was reduced from 13.3 kPa to 399 Pa in absolute pressure over 40 minutes, and the distilled phenol was removed from the system.

[0083] Thereafter, the temperature outside the reaction vessel was raised to 280° C., and the absolute pressure in the reaction vessel was reduced to 30 Pa to carry out a polycondensation reaction. When the agitator in the reaction vessel reached a predetermined stirring power, the polycondensation reaction was terminated. The time from raising the temperature to 280° C. to completing the polymerization (second-stage polymerization time) was 185 minutes.

[0084] Next, the reactor was restored to an absolute pressure of 101.3 kPa with nitrogen, and then the gauge pressure was increased to 0.2 MPa, and the polycarbonate resin was extracted in a strand form from the bottom of the reactor to obtain a strand-shaped polycarbonate resin. The strand was then pelletized using a rotary cutter to obtain a pellet-shaped polycarbonate resin. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 19,400, and the pellet YI was 14.9.

[0085] <Example 2> [Reaction process] The same procedure as in Example 1 was carried out to obtain 204 g of a crude cake of TMBPF.

[0086] [Cleaning process] The same procedure as in Example 1 was repeated except that tetrahydrofuran was used instead of methyltetrahydropyran.

[0087] [Refining process] The same procedure as in Example 1 was carried out to obtain white TMBPF.

[0088] [Color evaluation] The obtained TMBPF was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 0, and the Hazen color number 30 minutes after dissolution was 5.

[0089] [Polycarbonate resin color tone] The obtained TMBPF was used to polymerize a polycarbonate resin in the same manner as in Example 1. The time from raising the temperature to 280°C to the end of the polymerization (second-stage polymerization time) was 185 minutes. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 20300, and the pellet YI was 14.6.

[0090] <Example 3> [Reaction process] The same procedure as in Example 1 was carried out to obtain 203 g of a crude cake of TMBPF.

[0091] [Cleaning process] The same procedure as in Example 1 was repeated except that 300 g of toluene was used instead of methyltetrahydropyran.

[0092] [Refining process] The same procedure as in Example 1 was carried out to obtain a refined cake of TMBPF. 150 g of the obtained refined cake of TMBPF was placed in a 500 mL glass beaker, 300 g of diethyl ether was added, and the mixture was thoroughly stirred with a spoon made of Teflon (registered trademark), and then solid-liquid separation was performed again using a centrifuge to obtain a wet cake of TMBPF. This wet cake of TMBPF was distilled at an oil bath temperature of 100° C. under reduced pressure to remove low boiling points, thereby obtaining a white TMBPF. White TMBPF was obtained.

[0093] [Color evaluation] The obtained TMBPF was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 0, and the Hazen color number 30 minutes after dissolution was 3.

[0094] [Polycarbonate resin color tone] The obtained TMBPF was used to polymerize a polycarbonate resin in the same manner as in Example 1. The time from raising the temperature to 280°C to ending the polymerization (second-stage polymerization time) was 190 minutes. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 19000, and the pellet YI was 14.5.

[0095] <Example 4> [Reaction process] The same procedure as in Example 1 was carried out to obtain 201 g of a crude cake of TMBPF.

[0096] [Cleaning process] The same procedure as in Example 1 was repeated except that 300 g of toluene was used instead of methyltetrahydropyran.

[0097] [Refining process] The same procedure as in Example 1 was carried out to obtain a refined cake of TMBPF. The obtained refined cake of TMBPF was placed in a 500 mL glass beaker, 300 g of diisopropyl ether was added, and the mixture was thoroughly stirred with a spoon made of Teflon (registered trademark), and then solid-liquid separation was carried out again using a centrifuge to obtain a wet cake of TMBPF. The wet cake of TMBPF was subjected to distillation of low boiling points at an oil bath temperature of 100° C. under reduced pressure using an evaporator equipped with an oil bath, to obtain a white TMBPF.

[0098] [Color evaluation] The obtained TMBPF was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 0, and the Hazen color number 30 minutes after dissolution was 3.

[0099] [Polycarbonate resin color tone] The obtained TMBPF was used to polymerize a polycarbonate resin in the same manner as in Example 1. The time from raising the temperature to 280°C to the end of the polymerization (second-stage polymerization time) was 190 minutes. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 20,000, and the pellet YI was 14.5.

[0100] <Comparative Example 1> [Reaction process] The same procedure as in Example 1 was carried out to obtain 202 g of a crude cake of TMBPF.

[0101] [Cleaning process] The same procedure as in Example 1 was repeated except that acetone was used instead of methyltetrahydropyran.

[0102] [Refining process] The same procedure as in Example 1 was carried out to obtain white TMBPF.

[0103] [Color evaluation] The obtained TMBPF was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 32, and the Hazen color number 30 minutes after dissolution was 120.

[0104] [Polycarbonate resin color tone] The obtained TMBPF was used to polymerize a polycarbonate resin in the same manner as in Example 1. The time from raising the temperature to 280°C to the end of the polymerization (second-stage polymerization time) was 185 minutes. The viscosity average molecular weight (Mv) of the obtained polycarbonate resin was 21000, and the pellet YI was 18.1.

[0105] The results of Examples 1 to 4 and Comparative Example 1 are summarized in Table 1. From these results, it is understood that TMBPF with excellent color tone and color tone stability can be produced by crystallizing and / or washing the wet cake using an organic solvent having an ether bond. In addition, polycarbonate resin with excellent color tone can be produced by using TMBPF with excellent color tone as a raw material.

[0106] [Table 1]

[0107] <Example 5> 100 g of TMBPF manufactured by Tokyo Chemical Industry Co., Ltd. was placed in a 500 mL glass beaker, 150 g of methyltetrahydropyran was added, and the mixture was thoroughly stirred with a Teflon (registered trademark) spoon, followed by solid-liquid separation using a centrifuge to obtain a wet cake of TMBPF. The obtained wet cake of TMBPF was subjected to distillation of low boiling fractions at an oil bath temperature of 100°C under reduced pressure using an evaporator equipped with an oil bath, thereby obtaining white TMBPF.

[0108] [Color evaluation] The obtained TMBPF was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 45, and the Hazen color number 30 minutes after dissolution was 60.

[0109] <Comparative Example 2> Using TMBPF manufactured by Tokyo Chemical Industry Co., Ltd., which was used in Example 5, the color tone was evaluated in the same manner as in Example 1. The Hazen color number immediately after dissolution was 63, and the Hazen color number 30 minutes after dissolution was 500.

[0110] The results of Example 5 and Comparative Example 2 are summarized in Table 2. From these results, it was found that the quality of TMBPF, which has poor color tone and color tone stability, can be improved by washing with an organic solvent having an ether bond.

[0111] [Table 2] [Industrial Applicability]

[0112] The bisphenol produced by the bisphenol production method of the present invention is useful as a resin raw material such as a polycarbonate resin, an epoxy resin, an aromatic polyester resin, etc., or as an additive such as a curing agent, a color developer, an anti-fading agent, or other bactericide, antibacterial, antifungal, etc.

Claims

1. A method for producing bisphenol comprising the following steps A to D: Step A: A step of producing bisphenol from an aromatic alcohol and a ketone or aldehyde to obtain bisphenol Step B: A step of washing the bisphenol obtained in step A with water in an oil-water separated state to obtain an organic phase containing bisphenol. Step C: A step of crystallizing the organic phase containing bisphenol obtained in step B to obtain a slurry liquid containing bisphenol. Step D: A step of subjecting the bisphenol-containing slurry obtained in step C to solid-liquid separation to obtain a bisphenol cake. In the step C and / or the step D, an organic compound having an ether bond and a melting point of 40° C. or less is used, The method for producing bisphenol, wherein the bisphenol is a compound represented by the following general formula (1): 【Chemistry 1】 (In formula (1), R １ ~R ４ are each independently selected from a hydrogen atom, a halogen atom, an unsubstituted alkyl group, an unsubstituted alkoxy group, an unsubstituted aryl group, and an amino group. ５ and R ６ are each independently selected from a hydrogen atom, an unsubstituted alkyl group, an unsubstituted alkoxy group, and an unsubstituted aryl group.

2. 2. The method for producing bisphenol according to claim 1, further comprising a step of neutralizing the aqueous phase obtained by oil-water separation so that the aqueous phase has a pH of 8 or more and 13 or less in the step B.

3. The method for producing bisphenol according to claim 1 or 2, wherein the step A is carried out in the presence of an acid catalyst.

4. The method for producing bisphenol according to any one of claims 1 to 3, wherein the organic compound having an ether bond is a compound represented by the following general formula (4): 【Chemistry 2】 (In formula (4), R １１ and R １２ are each independently any one selected from the group consisting of an alkyl group, an alkylene group, an alkenyl group, and an aryl group; R １１ and R １２ and may be crosslinked.)

5. The method for producing bisphenol according to any one of claims 1 to 4, wherein the bisphenol is any one selected from the group consisting of bis(4-hydroxy-2,6-dimethylphenyl)methane, 1,1-bis(4-hydroxyphenyl)ethane, 2,2-bis(4-hydroxy-2-methylphenyl)propane, and 9,9-bis(4-hydroxyphenyl)fluorene.

6. A method for producing a polycarbonate, comprising: producing a polycarbonate resin using the bisphenol produced by the method for producing bisphenol according to any one of claims 1 to 5.

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