Method for producing bisphenol and method for producing polycarbonate resin

Abstract

To provide a method for producing a bisphenol with excellent melting colors and also provide a method for producing a polycarbonate resin with excellent color tone using the bisphenol.SOLUTION: A method for producing a bisphenol includes a preparation step for mixing a ketone with a sulfuric acid solution to prepare a liquid mixture and a reaction step for reacting the liquid mixture with an aromatic alcohol in the presence of an acid catalyst to form a bisphenol.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. [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 and 2,2-bis(4-hydroxy-3-methylphenyl)propane (see Patent Documents 1 and 2). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Application Publication No. 62-138443 [Patent Document 2] JP 2008-214248 A Summary of the Invention [Problem to be solved by the invention]

[0004] Polycarbonate resin, which is a typical application of bisphenol, is required to be colorless and transparent. The color tone of polycarbonate resin is greatly affected by the color tone of the raw material. Therefore, the color tone of the raw material bisphenol is also required to be colorless. Here, since it is difficult to directly quantify the color of bisphenol powder, the color tone when dissolved in a solvent may be taken as the color tone of bisphenol. On the other hand, among the methods for producing polycarbonate resin, the melting method in particular includes a step of melting bisphenol by exposing it to high temperature. Therefore, the color tone of bisphenol is also required to be thermally stable. In the present invention, the color tone in the molten state is referred to as the "melt color".

[0005] When the present inventors produced bisphenol using commercially available acetone by a conventional method, they found that the molten bisphenol was colored, i.e., the thermal stability of the color tone of the bisphenol produced by the conventional method was insufficient.

[0006] The present invention has been made in view of the above-mentioned conventional circumstances, and has an object to provide a method for producing a bisphenol having a good melt color. Another object of the present invention is to provide a method for producing a polycarbonate resin having a good color tone by using the bisphenol. [Means for solving the problem]

[0007] As a result of intensive research to solve the above problems, the present inventors have found that bisphenol has excellent melt color when used as a raw material of ketone to which sulfuric acid has been added in advance. In addition, they have found that polycarbonate resin with excellent color tone can be produced by using this bisphenol, and have completed the present invention.

[0008] That is, the gist of the present invention resides in the following [1] to [5]. [1] A method for producing bisphenol, comprising: a preparation step of mixing a ketone with a sulfuric acid solution to prepare a mixed solution; and a reaction step of reacting the mixed solution with an aromatic alcohol in the presence of an acid catalyst to produce bisphenol. [2] The method for producing bisphenol according to [1], wherein the mixed solution has a mass ratio of sulfuric acid contained in the sulfuric acid solution to ketone of 0.05 or less. [3] The concentration of sulfuric acid contained in the sulfuric acid solution is 70% by mass or more based on the total sulfuric acid solution. The method for producing bisphenol according to [1] or [2], wherein the content of the bisphenol in the bisphenol-containing gas is 0.00 mass% or less. [4] The method for producing bisphenol according to any one of [1] to [3], wherein the ketone contains an aldehyde. [5] The method for producing bisphenol according to any one of [1] to [4], wherein the aromatic alcohol includes at least one selected from the group consisting of phenol, cresol and xylenol. [6] The method for producing a bisphenol according to any one of [1] to [5], wherein the bisphenol is 2,2-bis(4-hydroxy-3-methylphenyl)propane. [7] A method for producing a polycarbonate resin, comprising using bisphenol produced by the method for producing bisphenol according to any one of [1] to [6]. Effect of the Invention

[0009] According to the production method of the present invention, a bisphenol having a good melt color is provided by using a ketone to which sulfuric acid has been added as a raw material. In addition, a polycarbonate resin having an excellent color tone is provided by the production method of the polycarbonate resin using this bisphenol. Furthermore, since sodium hypophosphite, which is used in the conventional method disclosed in Patent Document 2, is not used, the wastewater load is also reduced. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] The following is a detailed description of an embodiment of the present invention, but the description of the constituent elements described below is an example of an embodiment of the present invention, and the present invention is not limited to the following description as long as it does not deviate from the gist of the present invention. 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.

[0011] [Preparation process] The method for producing bisphenol according to one embodiment of the present invention includes a preparation step of mixing a ketone with a sulfuric acid solution to prepare a mixed solution. As shown in the following examples, ketones produced industrially usually contain a small amount of aldehyde. It is presumed that the inclusion of the preparation step reduces the amount of impurities such as aldehyde contained in the ketone, and improves the melt color of the produced bisphenol. For example, when the impurity is acetaldehyde, the acetaldehyde is oxidized by sulfuric acid to acetic acid, thereby suppressing the adverse effect on the melt color of the bisphenol.

[0012] (Ketone) Ketones are usually compounds represented by the following general formula (1). [ka] In the general formula (1), R 5 and R 6 are each independently 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.

[0013] Specific examples of the compound represented by general formula (1) include ketones such as acetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, decanone, undecanone, and dodecanone; 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.

[0014] (aldehyde) Ketones may contain one or more aldehydes as impurities. Aldehydes are represented by the general formula (1) above, R 5 and R 6 are each independently a hydrogen atom, an alkyl group or an aryl group, and at least one of them 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.

[0015] Specific examples of the aldehyde include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentanaldehyde, hexanealdehyde, heptanealdehyde, octanaldehyde, nonanealdehyde, decanaldehyde, undecanealdehyde, dodecanealdehyde, and benzaldehyde.

[0016] The content of aldehyde in the ketone is preferably 5% by mass or less, preferably 3% by mass or less, more preferably 1% by mass or less, and even more preferably 0.05% by mass or less. The lower limit is not particularly limited, but is preferably 0.1 ppm by mass or more, more preferably 0.5 ppm by mass or more, and even more preferably 1 ppm by mass or more. By using a ketone with a low aldehyde content, a bisphenol having a good melt color can be produced. Furthermore, a polycarbonate resin having an excellent color tone can be produced using the obtained bisphenol. The content of aldehyde in the ketone can be quantified, for example, by gas chromatography.

[0017] (sulfuric acid solution) The sulfuric acid solution to be mixed with the ketone usually contains water, but may be sulfuric acid that does not contain other components such as water. That is, the concentration of sulfuric acid contained in the sulfuric acid solution is preferably 70% by mass or more, more preferably 71% by mass or more, and particularly preferably 72% by mass or more, based on the entire sulfuric acid solution. On the other hand, it is usually 100% by mass or less, preferably 99% by mass or less, more preferably 98% by mass or less, and particularly preferably 97% by mass or less. When the concentration of sulfuric acid is 100% by mass, the sulfuric acid solution essentially refers to sulfuric acid itself. When the sulfuric acid concentration is within the above range, the amount of impurities contained in the ketone can be sufficiently reduced. Also, when the concentration is 90 mass % or less, side reactions can be reduced and the melt color of the bisphenol can be improved.

[0018] The method for mixing the ketone and the sulfuric acid solution is not particularly limited, but it is preferable to add the sulfuric acid solution to the reaction vessel in which the ketone has been added. The temperature during mixing is not particularly limited, but may be room temperature, for example 25°C. The mixing ratio of ketone and sulfuric acid is preferably 0.05 or less, more preferably 0.04 or less, and particularly preferably 0.03 or less, as a mass ratio of sulfuric acid contained in the sulfuric acid solution to ketone. Also, it is preferably 0.00001 or more, more preferably 0.00005 or more, and particularly preferably 0.0001 or more. Within the above range, the amount of impurities contained in ketone can be sufficiently reduced. Also, it is possible to reduce side reactions and improve the melt color of bisphenol.

[0019] [Reaction process] A method for producing bisphenol, which is one embodiment of the present invention, includes a reaction step of reacting the mixed liquid with an aromatic alcohol in the presence of an acid catalyst to produce bisphenol. The bisphenol produced is usually a compound represented by the following general formula (2).

[0020] [ka] 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, the alkoxy group, the aryl group, and the like may be substituted or unsubstituted. The alkyl group and the alkoxy group may be linear, branched, or cyclic. R 1 ~R 4 Specific 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.

[0021] R 5 and R 6 is R in the above general formula (1). 5 and R 6 It is synonymous with that in.

[0022] Specific examples of the compound represented by the above general formula (2) include 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, 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 and the like, but are not limited thereto.

[0023] Among these, preferred bisphenols are 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C) or 9,9-bis(4-hydroxyphenyl)fluorene, and particularly preferred is 2,2-bis(4-hydroxy-3-methylphenyl)propane (bisphenol C).

[0024] (Aromatic alcohol) The raw material aromatic alcohol used in the production of bisphenol is usually a compound represented by the following general formula (3). [ka] In the general formula (3), R 1 ~R 4 is R in the above general formula (2). 1 ~R 4 It is synonymous with that in.

[0025] R 2 and R3 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.

[0026] Specific examples of the compound represented by the above general formula (3) include phenol, methylphenol (cresol), dimethylphenol (xylenol), ethylphenol, propylphenol, butylphenol, methoxyphenol, ethoxyphenol, propoxyphenol, butoxyphenol, benzylphenol, and phenylphenol. 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.

[0027] In the reaction of condensing aromatic alcohol and ketone, if the molar ratio of aromatic alcohol to ketone (moles of aromatic alcohol / moles of ketone) is low, the ketone will polymerize, but if it is high, the aromatic alcohol will be lost unreacted, making it uneconomical. Therefore, the molar ratio of aromatic alcohol to ketone is preferably 1.5 or more, more preferably 1.7 or more, and even more preferably 2.0 or more. It is also preferably 10 or less, more preferably 5 or less, and even more preferably 3 or less.

[0028] (acid catalyst) Examples of the acid catalyst used in the production of bisphenol include hydrochloric acid, hydrogen chloride gas, phosphoric acid, aromatic sulfonic acids such as p-toluenesulfonic acid, aliphatic sulfonic acids such as methanesulfonic acid, etc. Among these, hydrochloric acid or hydrogen chloride gas is particularly preferred from the viewpoint of suppressing side reactions.

[0029] If the molar ratio of the acid catalyst to the ketone used in the condensation reaction (moles of acid catalyst / moles of ketone) is low, the acid catalyst will be diluted by the water by-produced as the condensation reaction proceeds, and the reaction will take time. If the molar ratio is high, the ketone may polymerize or the bisphenol produced may decompose. For these reasons, it is important to select the appropriate ratio of the acid catalyst to the ketone used in the condensation reaction. The molar ratio of the solvent is preferably 0.01 or more, more preferably 0.05 or more, and even more preferably 0.1 or more. The upper limit is preferably 10 or less, more preferably 8 or less, and even more preferably 5 or less.

[0030] (Thiol) In the reaction step, a thiol may be used as a promoter when condensing a ketone with an aromatic alcohol. By using a thiol as a promoter, for example, in the production of 2,2-bis(4-hydroxy-3-methylphenyl)propane, the production of the 24 isomer (2-(2-hydroxy-3-methylphenyl)-2-(4-hydroxy-3-methylphenyl)propane) is suppressed, and the selectivity of the 44 isomer (2,2-bis(4-hydroxy-3-methylphenyl)propane) is increased. In addition, the polymerization activity during the production of the polycarbonate resin is increased, and the color tone of the resulting polycarbonate resin is improved. Although the details of the reason for the improvement in the polymerization activity during the production of the polycarbonate resin and the improvement in the color tone of the resulting polycarbonate resin are not clear, it is presumed that the use of a thiol suppresses the production of inhibitors for the polymerization reaction in the production of the polycarbonate resin and suppresses the production of substances that deteriorate the color tone.

[0031] Examples of thiols used as the promoter include mercaptocarboxylic acids such as mercaptoacetic acid, thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 4-mercaptobutyric acid; alkyl thiols such as 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, and pentadecyl mercaptan; and aryl thiols such as mercaptophenol.

[0032] If the molar ratio of thiol to ketone used in the condensation reaction (moles of thiol / moles of ketone) is low, the effect of improving the reaction selectivity of bisphenol by using thiol cannot be obtained, and if it is high, it may be mixed with bisphenol and deteriorate the quality. For these reasons, the lower limit of the molar ratio of thiol to ketone 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.

[0033] (Organic solvent) In the production of bisphenol, an organic solvent can be used to dissolve or disperse the produced bisphenol and to wash and purify the bisphenol. The organic solvent is not particularly limited as long as it does not inhibit the bisphenol production reaction and does not cause a side reaction when dissolving bisphenol, and examples thereof include aromatic hydrocarbons, aliphatic alcohols, and aliphatic hydrocarbons. Here, the aromatic alcohols and ketones, which are the substrates, the thiols, which are the co-catalysts, and the bisphenol product are excluded from the organic solvent. The solvents that are not used in the bisphenol production reaction and are supplied during washing and purification are not limited to the above, and aromatic alcohols and ketones can also be used as solvents. These organic solvents may be used alone or in combination of two or more.

[0034] Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene. These organic solvents may be used alone or in combination of two or more. After being used in the production of bisphenol, aromatic hydrocarbons can be recovered and purified by distillation or the like for reuse. When aromatic hydrocarbons are to be reused, those with a low boiling point are preferred. One of the preferred aromatic hydrocarbons is toluene.

[0035] The aliphatic alcohol is an alkyl alcohol in which an alkyl group and a hydroxyl group are bonded. The aliphatic alcohol may be a monovalent aliphatic alcohol in which an alkyl group and one hydroxyl group are bonded, or a polyvalent aliphatic alcohol in which an alkyl group and two or more hydroxyl groups are bonded. The alkyl group may be linear or branched, unsubstituted, or part of the carbon atoms of the alkyl group may be substituted with an oxygen atom.

[0036] The aliphatic alcohol is preferably an alcohol having an alkyl group and one hydroxy group bonded thereto, more preferably an alcohol having an alkyl group having 1 to 8 carbon atoms and one hydroxy group bonded thereto, and even more preferably an alcohol having an alkyl group having 1 to 5 carbon atoms and one hydroxy group bonded thereto.

[0037] Specific examples of the aliphatic alcohol include 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, n-dodecanol, ethylene glycol, diethylene glycol, triethylene glycol, etc. One of the preferred aliphatic alcohols is methanol.

[0038] Examples of aliphatic hydrocarbons include linear hydrocarbons having 5 to 18 carbon atoms, such as n-pentane, n-hexane, n-heptane, and n-octane; branched hydrocarbons having 5 to 18 carbon atoms, such as isooctane; and cyclic hydrocarbons having 5 to 18 carbon atoms, such as cyclohexane, cyclooctane, and methylcyclohexane.

[0039] If the mass ratio of the organic solvent to the ketone used in the condensation reaction (mass of organic solvent / mass of ketone) is too high, the ketone and aromatic alcohol do not react easily, and the reaction takes a long time. If the mass ratio is too low, the polymerization of the ketone is promoted, and the bisphenol produced may solidify. For these reasons, the mass ratio of the organic solvent to the ketone at the time of charging is preferably 0.5 or more, more preferably 1 or more. The upper limit is preferably 100 or less, more preferably 50 or less. The organic solvent may be supplied in portions. When the organic solvent is supplied in portions, the total amount of the organic solvent used in preparing the reaction solution relative to the ketone is preferably within the above range.

[0040] By dispersing the produced bisphenol in the organic solvent without completely dissolving it, side reactions can be suppressed and the bisphenol is less likely to decompose. In addition, it is preferable to use a solvent in which bisphenol has a low solubility at room temperature, since this can reduce losses (e.g., losses to the filtrate during crystallization) when recovering bisphenol from the reaction liquid after the reaction is completed. Examples of organic solvents in which bisphenol has a low solubility at room temperature include aromatic hydrocarbons. For this reason, it is preferable that the organic solvent contains aromatic hydrocarbons as a main component. When used in a process for producing bisphenol or a process for washing, it is necessary to select a solvent with a boiling point higher than the operating temperature. In addition, when washing is performed in a state in which bisphenol is dissolved and separated into two phases, an oil phase and an aqueous phase, it is preferable that the solvent is highly hydrophobic and easy to separate into phases.

[0041] (Preparation of reaction solution) The method for preparing the reaction solution is not particularly limited, and examples thereof include a method in which an aromatic alcohol, an acid catalyst, and, if necessary, an organic solvent are sequentially supplied to a mixed solution obtained by mixing a ketone and a sulfuric acid solution, a method in which an aromatic alcohol and an organic solvent are mixed into a mixed solution obtained by mixing a ketone and a sulfuric acid solution, and then an acid catalyst is supplied, and a method in which an aromatic alcohol, hydrogen chloride, and, if necessary, an organic solvent are mixed into the mixed solution obtained by mixing a ketone and a sulfuric acid solution, and then an organic solvent is supplied. and supplying a mixed solution of a ketone and a sulfuric acid solution to the mixed solution. Alternatively, the reaction can be controlled by mixing all the raw materials at a low temperature and then gradually increasing the temperature until the reaction to produce bisphenol occurs.

[0042] (Reaction conditions) The reaction temperature for the bisphenol production reaction is adjusted as appropriate depending on the type of bisphenol produced, the production scale, etc., but is preferably -30°C to 100°C. The bisphenol production reaction is a condensation reaction, and water is by-produced, so the reaction temperature is preferably below the boiling point of water. More preferably, the reaction temperature is 95°C or lower, followed by 90°C or lower. If the reaction temperature is too low, the time required for the reaction increases, so the reaction temperature is preferably -20°C or higher, followed by -15°C or higher, -5°C or higher, followed by 0°C or higher.

[0043] The reaction time of the production reaction is adjusted appropriately depending on the type of bisphenol to be produced, the reaction temperature, the production scale, etc., but is usually 0.5 to 500 hours. The reaction time of the production reaction may be 400 hours or less or 350 hours or less, but if it is too long, the produced bisphenol will decompose, so it 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 preferably 1 hour or more, more preferably 1.5 hours or more.

[0044] The reaction pressure of the production reaction is not particularly limited and may be, for example, atmospheric pressure. It is also preferable to carry out the reaction under an inert atmosphere. Specific examples include an atmosphere of nitrogen, carbon dioxide, or argon.

[0045] (purification method) The bisphenol produced in the reaction step may be further purified. The purification can be carried out by a conventional method. For example, purification can be carried out by a simple means such as crystallization or column chromatography. Specifically, after the condensation reaction, the organic phase obtained by separating the reaction solution is washed with water or saline, and further neutralized and washed with sodium bicarbonate water, if necessary. The washed organic phase is then cooled and crystallized. When a large amount of aromatic alcohol is used, the excess aromatic alcohol is distilled off before the crystallization, and then the crystallization is carried out. The crystallization may be carried out multiple times, but since a part 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.

[0046] The precipitated bisphenol may be subjected to suspension washing using an aromatic hydrocarbon or the like as a washing solvent, or may be dried. The drying method may be drying under reduced pressure or drying under normal pressure. The drying temperature may be appropriately determined, and for example, drying may be performed at 50 to 120°C for 2 to 15 hours.

[0047] (Uses of bisphenol) Bisphenols can be used as components, curing agents, additives, or precursors thereof in 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. They are also useful as additives such as color developers and discoloration inhibitors for thermal recording materials, bactericides, and antibacterial and antifungal agents. Among these, since it can impart good mechanical properties, it is preferably used as a raw material (monomer) for thermoplastic resins and thermosetting resins, and more preferably used as a raw material for polycarbonate resins and epoxy resins. It is also preferably used as a color developer, and more preferably used in combination with a leuco dye and a discoloration temperature regulator.

[0048] (Polycarbonate resin) Another embodiment of the present invention is a method for producing a polycarbonate resin, which is characterized by using the bisphenol produced by the above-mentioned production method. The polycarbonate resin can be produced by, for example, a method of subjecting a bisphenol to an ester exchange reaction with a carbonate diester such as diphenyl carbonate in the presence of an alkali metal compound and / or an alkaline earth metal compound. In addition, only one type of bisphenol may be used to produce the polycarbonate resin, or two or more types may be used. By using two or more types of bisphenol, a copolymer polycarbonate resin can be produced. In addition, a dihydroxy compound other than the above bisphenols can be used in combination and reacted. The above transesterification reaction can be carried out by appropriately selecting a known method, but an example in which bisphenol and diphenyl carbonate are used as raw materials will be described below.

[0049] In the above-mentioned 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 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. Also, it is usually 1.3 moles or less, preferably 1.2 moles or less.

[0050] As for the method of supplying the raw materials, bisphenol and diphenyl carbonate 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.

[0051] When producing a polycarbonate resin by the transesterification reaction of diphenyl carbonate and bisphenol, a transesterification catalyst is usually used. In the above-mentioned method for producing a polycarbonate resin, it is preferable to use an alkali metal compound and / or an alkaline earth metal compound as the transesterification catalyst. These may be used alone or in any combination and ratio of two or more. In practical terms, it is preferable to use an alkali metal compound.

[0052] The amount of the catalyst used is usually 0.05 μmol or more, preferably 0.08 μmol or more, more preferably 0.10 μmol or more, per mole of bisphenol or diphenyl carbonate, and the upper limit is usually 100 μmol or less, preferably 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 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.

[0053] 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 where a transesterification catalyst is added to produce a polymer.

[0054] In the production of polycarbonate resin using the above bisphenol, the polymerization reaction temperature is preferably 80 to 400°C, particularly 150 to 350°C. The polymerization time is appropriately adjusted depending on the ratio of raw materials and the molecular weight of the desired polycarbonate resin, but since a long polymerization time leads to deterioration in quality such as deterioration in color tone, it is preferably 10 hours or less, more preferably 8 hours or less. The lower limit of the polymerization time is usually 0.1 hours or more, or 0.3 hours or more. EXAMPLES

[0055] 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.

[0056] [Raw materials and reagents] In the following examples and comparative examples, orthocresol, toluene, sodium hydroxide, 35% by mass hydrochloric acid, 98% by mass sulfuric acid, dodecanethiol, reagent acetone, acetaldehyde, sodium bicarbonate, cesium carbonate, acetonitrile, acetic acid, ammonium acetate, and bisphenol C were used, all of which were manufactured by Fujifilm Wako Pure Chemical Industries, Ltd. Diphenyl carbonate used was a product manufactured by Mitsubishi Chemical Corporation. Acetone containing 1% by mass of acetaldehyde was prepared by supplying a predetermined amount of acetaldehyde to reagent acetone. Sulfuric acid of each concentration was prepared by diluting 98% by mass sulfuric acid with an appropriate amount of demineralized water.

[0057] [analysis] <Acetaldehyde in acetone> Analysis of acetaldehyde in the reagent acetone was performed by gas chromatography under the following conditions: The amount of acetaldehyde in the reagent acetone was 30 ppm by mass. Equipment: Shimadzu GC-2014 Agilent FFAP 0.53mm×60m 1.0μm Detection method: FID Vaporizer temperature: 150℃ Detector temperature: 240℃ From 0 to 8 minutes of analysis time, the column temperature was kept at 40°C, from 8 to 40 minutes of analysis time, the column temperature was gradually increased to 240°C at 5°C per minute, and from 40 to 50 minutes of analysis time, the column temperature was maintained at 240°C. Quantitative method: Internal standard method using toluene as the internal standard

[0058] <Analysis of Bisphenol C> The composition analysis of bisphenol C was carried out by high performance liquid chromatography under the following procedure and conditions. Since the purity of the produced bisphenol C is usually 99% by mass or more, this analysis was used to confirm that the obtained solid was bisphenol C. Equipment: Shimadzu Corporation "LC-2010A" Imtakt ScherzoSM-C18 3μm 250mm×3.0mmID·Low pressure gradient method ·Analysis temperature: 40℃ ·Eluent composition: Solution A: Ammonium acetate: acetic acid: demineralized water = 3.000 g: 1 mL: 1 L solution Solution B: Ammonium acetate: acetic acid: acetonitrile: demineralized water = 1.500 g: 1 mL: 900 mL: 150 mL solution At analysis time 0 minutes, the eluent composition is A:B = 60:40 (volume ratio, same below). During the analysis time from 0 to 41.67 minutes, the ratio of A solution to B solution was gradually changed to 10:90. From 41.67 to 50 minutes of analysis, the ratio of A solution to B solution was kept at 10:90. Analysis was carried out at a flow rate of 0.34 mL / min.

[0059] <Measurement of pH> The pH measurement was performed on the aqueous phase at 25 °C taken out from the flask using a pH meter "pH METE ES-73" manufactured by Horiba, Ltd.

[0060] <Electrical conductivity> The measurement of electrical conductivity was performed on the aqueous phase at 25 °C taken out from the flask using a conductivity meter "COND METER D-71" manufactured by Horiba, Ltd.

[0061] <Melt color of bisphenol C> The melt color of bisphenol C was measured by putting 20 g of bisphenol C into a test tube "P-24" (24 mm φ × 200 mm) manufactured by Nippon Denshikagaku Glass Co., Ltd., melting it at 190 °C for 30 minutes, and using "SE6000" manufactured by Nippon Denshoku Industries Co., Ltd. to measure its Hazen color number (APHA).

[0062] <Viscosity-average molecular weight> The viscosity-average molecular weight (Mv) of the polycarbonate resin was measured 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 tube, and calculating the viscosity-average molecular weight (Mv) by the following formula. ηsp / C = [η](1 + 0.28ηsp) [η] = 1.23×10 -4 Mv 0.83

[0063] <Pellet YI> The pellet YI (transparency of the polycarbonate resin) was evaluated by measuring the YI value (yellowness index value) in the reflected light of the polycarbonate resin pellets in accordance with ASTM D1925. The apparatus used was a spectrophotometer "CM-5" manufactured by Konica Minolta, Inc., and the measurement conditions were a measurement diameter of 30 mm and SCE was selected. The calibration glass for petri dish measurements, "CM-A212", was fitted into the measurement section, and the 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 YI was 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.

[0064] <Example 1> (1-1) Production of bisphenol C In a separable flask equipped with a thermometer, a dropping funnel, a jacket, and an anchor-type stirring blade, 5 g of toluene, 230 g of ortho-cresol, and 2 g of dodecanethiol were placed under a nitrogen atmosphere, and while maintaining the internal temperature at 30° C., 210 g of 35% by mass hydrochloric acid was added with stirring to prepare mixed solution A1. Next, 65 g of acetone containing 1% by mass of acetaldehyde and 2.2 g of 98% by mass sulfuric acid were added to an Erlenmeyer flask and stirred to obtain a mixed liquid B1, which was then placed in the dropping funnel. While maintaining the mixed liquid A1 at 25°C, the mixed liquid B1 in the dropping funnel was added dropwise to the mixed liquid A1 over a period of 1 hour with stirring, and the mixture was stirred for an additional 2 hours while maintaining the temperature at 30°C to obtain a reaction liquid C1 of bisphenol C.

[0065] 290g of 25% sodium hydroxide solution and 250g of toluene were added to the reaction solution C1 of bisphenol C, and the mixture was stirred and heated to 75°C. Since sodium chloride produced by neutralization remained undissolved, demineralized water was added to completely dissolve it, and the mixture was allowed to stand 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 D1. At 75° C., 3% by mass sodium bicarbonate solution was added to the obtained organic phase D1, and the mixture was stirred to neutralize, 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 to obtain an organic phase E1. The organic phase E1 was gradually cooled from 75° C. to 5° C. to precipitate crystals containing bisphenol C. The resulting liquid containing the crystals containing bisphenol C was subjected to solid-liquid separation by filtration under reduced pressure to obtain 210 g of a cake containing bisphenol C.

[0066] In a separable flask equipped with a thermometer, a jacket, and an anchor-type stirring blade, 210 g of the bisphenol C-containing cake obtained under a nitrogen atmosphere, 100 g of desalted water, and 420 g of toluene were placed at room temperature, and the temperature was raised to 75 ° C., and then the mixture was left to stand to separate the oil and water. After the oil-water separation, the aqueous phase 1 was removed from the bottom of the separable flask to obtain an organic phase F1. The pH of the obtained aqueous phase 1 was 8.6, and the electrical conductivity was 130 μS / cm. 100 g of desalted water was added to the obtained organic phase F1, and the mixture was stirred for 30 minutes and left to stand to separate the oil and water. After the oil-water separation, the aqueous phase 2 was removed from the bottom of the separable flask to obtain an organic phase G1. The obtained aqueous phase 2 was 62 μS / cm, but the organic phase was repeatedly washed with 100 g of desalted water until the aqueous phase was 10 μS / cm or less, and an organic phase H1 was obtained. The organic phase H1 was gradually cooled from 75° C. to 5° C. to precipitate crystals containing bisphenol C. The obtained liquid containing the crystals containing bisphenol C was subjected to solid-liquid separation by filtration under reduced pressure to obtain 170 g of a cake containing bisphenol C.

[0067] Using an evaporator equipped with an oil bath, the low boiling fraction was distilled off under reduced pressure at an oil bath temperature of 90°C to obtain 142 g of a white solid. A portion of the obtained white solid was analyzed using high performance liquid chromatography and confirmed to be bisphenol C.

[0068] (1-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (1-1) was measured, and it was found to be 40 on the Hazen color scale.

[0069] <Example 2> (2-1) Production of bisphenol C The same procedure as in (1-1) of Example 1 was repeated, except that 2.6 g of 85% by mass sulfuric acid was used instead of 2.2 g of 98% by mass sulfuric acid in (1-1) of Example 1. (2-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (2-1) was measured, and it was found to be 25 on the Hazen color scale.

[0070] <Example 3> (3-1) Production of bisphenol C The same procedure as in (1-1) of Example 1 was repeated, except that 3.1 g of 70% by mass sulfuric acid was used instead of 2.2 g of 98% by mass sulfuric acid in (1-1) of Example 1. (3-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (3-1) was measured, and the Hazen color scale was 34.

[0071] <Comparative Example 1> (A-1) Production of bisphenol C The same procedure as in (1-1) of Example 1 was repeated, except that in (1-1) of Example 1, 2.2 g of 98% by mass sulfuric acid was not supplied. (A-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (A-1) was measured and found to be 185 on the Hazen color scale.

[0072] <Comparative Example 2> (B-1) Production of bisphenol C The same procedure as in (1-1) of Example 1 was repeated, except that 4.3 g of 50% by mass sulfuric acid was used instead of 2.2 g of 98% by mass sulfuric acid in (1-1) of Example 1. (B-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (B-1) was measured and found to be 55 on the Hazen color scale.

[0073] In Examples 1 to 3 and Comparative Examples 1 and 2, the concentration of sulfuric acid supplied to the acetone containing acetaldehyde, the mass ratio of sulfuric acid to acetone, and the melt color of the obtained bisphenol C are summarized in Table 1. It is seen from Table 1 that the use of acetone containing acetaldehyde deteriorates the melt color of bisphenol, but when sulfuric acid is supplied in advance to acetone containing acetaldehyde, the concentration of the sulfuric acid is 70 mass % or more, and the mass ratio of sulfuric acid to acetone is 0.03 or less, bisphenol with a good melt color can be obtained.

[0074] [Table 1]

[0075] <Example 4> (4-1) Production of bisphenol C The same procedure as in Example 1 (1-1) was repeated, except that 65 g of reagent acetone and 10 mg of 80% by mass sulfuric acid were used instead of 65 g of acetone containing 1% by mass of acetaldehyde and 2.2 g of 98% by mass sulfuric acid in Example 1 (1-1). (4-2) Color of bisphenol The melt color of the bisphenol C obtained in (4-1) was measured and found to be 15 on the Hazen color scale.

[0076] (4-3) Color tone of polycarbonate resin In a 150 mL glass reaction vessel equipped with a stirrer and a distillation tube, 100.00 g (0.39 mol) of bisphenol C obtained in (4-1), 86.49 g (0.4 mol) of diphenyl carbonate, and 480 μL of a 400 ppm by mass aqueous solution of cesium carbonate 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. Thereafter, the reaction vessel was immersed in an oil bath at 200° C. to melt the contents. The agitator was rotated at 100 revolutions per minute, and the purified bisphenol C and diphenyl carbonate in the reaction vessel were 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 phenol. The pressure in the reaction vessel was then maintained at 13.3 kPa, and transesterification 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. 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. 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 24,800, and the pellet YI was 8.0.

[0077] <Comparative Example 3> (C-1) The same procedure as in (4-1) of Example 4 was repeated, except that 10 mg of 80% by mass sulfuric acid was not used. (C-2) Color tone of bisphenol C When the melt color of bisphenol C was measured in (C-1), it was found to be 25 on the Hazen color scale. (C-3) Color tone of polycarbonate resin (4-3) was carried out in the same manner as (4-3), except that the bisphenol C obtained in (C-1) was used instead of the bisphenol C obtained in (4-1). The pellet YI of the obtained polycarbonate resin was 9.6.

[0078] <Comparative Example 4> (D-1) In a separable flask equipped with a thermometer, a dropping funnel, a jacket, and an anchor-type stirring blade, 45.0 g (0.42 mol) of cresol, 18 g (0.31 mol) of reagent acetone, 6 g of toluene, and 2.0 g of mercaptopropionic acid were mixed under a nitrogen atmosphere to bring the internal temperature to 25°C. 47 g of 35% by mass hydrochloric acid was added thereto, and then 10 g of 98% sulfuric acid was dropped so that the internal temperature did not exceed 30°C (sulfuric acid concentration was 17% by mass as shown in the table below). After dropping, the mixture was stirred at 25°C for 6.5 hours to obtain a slurry-like reaction liquid. 40 g of water and 85 g of toluene were added to the obtained reaction liquid, and the temperature was raised to 80°C to completely dissolve bisphenol. After standing, the aqueous phase was removed to obtain organic phase 1. The obtained organic phase 1 was neutralized by adding an aqueous sodium bicarbonate solution. After standing, the aqueous phase was removed to obtain organic phase 2. The obtained organic phase 2 was washed with water to obtain organic phase 3. The obtained organic phase 3 was cooled to 20° C. to obtain a slurry solution. The obtained slurry solution was filtered to obtain a cake containing bisphenol C. The obtained cake containing bisphenol C was suspended and washed with toluene and dried to obtain 30 g of bisphenol C.

[0079] (D-2) Color tone of bisphenol The melt color of the bisphenol C obtained in (D-1) was measured and found to be 80 on the Hazen color scale.

[0080] The amount of acetaldehyde in the acetone used in Example 4 and Comparative Examples 3 and 4, the mass ratio of sulfuric acid to acetone, the melt color of the resulting bisphenol C, and the pellet YI of the resulting polycarbonate resin are summarized in Table 2. From Table 2, compared to Comparative Example 3 in which no sulfuric acid was added, It is found that when sulfuric acid is supplied in advance to acetone containing acetaldehyde, the concentration of the sulfuric acid is 70 mass% or more, and the mass ratio of sulfuric acid to acetone is 0.03 or less, bisphenol with a good melt color is obtained, and polycarbonate resin with a good color tone is obtained. Also, it is found that bisphenol with a significantly good melt color is obtained compared to Comparative Example 4 in which sulfuric acid is added later to a mixture of ketone, aromatic alcohol, and acid catalyst.

[0081] [Table 2]

Claims

1. 1. A method for producing bisphenol, comprising: a preparation step of mixing a ketone with a sulfuric acid solution to prepare a mixed solution; and a reaction step of reacting the mixed solution with an aromatic alcohol in the presence of an acid catalyst to produce bisphenol, wherein the mixed solution has a mass ratio of sulfuric acid contained in the sulfuric acid solution to ketone of 0.05 or less, and a concentration of sulfuric acid contained in the sulfuric acid solution is 70 mass% or more and 100 mass% or less with respect to the entire sulfuric acid solution.

2. The method for producing bisphenol according to claim 1 , wherein the ketone contains an aldehyde.

3. The method for producing bisphenol according to claim 1 or 2, wherein the aromatic alcohol comprises at least one selected from the group consisting of phenol, cresol and xylenol.

4. The method for producing a bisphenol according to any one of claims 1 to 3, wherein the bisphenol is 2,2-bis(4-hydroxy-3-methylphenyl)propane.

5. A method for producing a polycarbonate resin, comprising producing bisphenol by the method for producing bisphenol according to any one of claims 1 to 4, and using the produced bisphenol to produce a polycarbonate resin.

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