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 reduction step for mixing a ketone including an aldehyde with a reductant to reduce at least part of the aldehyde, and a reaction step for reacting the ketone having undergone the reduction step with an aromatic alcohol in the presence of hydrochloric acid.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 Laid-Open 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 this specification, the color tone in the molten state is referred to as the "melt color".

[0005] 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, and a method for producing a polycarbonate resin having a good color tone using the bisphenol. [Means for solving the problem]

[0006] As a result of intensive research aimed at solving the above problems, the present inventors have found that a bisphenol having a good melt color can be produced by contacting a ketone that has been previously treated with a reducing agent with an aromatic alcohol, and that a polycarbonate resin having a good color tone can be produced by using this bisphenol, thus completing the present invention. That is, the gist of the present invention lies in the following [1] to [7].

[0007] [1] a reduction step of mixing a ketone containing an aldehyde with a reducing agent to reduce at least a portion of the aldehyde; and a reaction step of reacting the ketone having been subjected to the reduction step with an aromatic alcohol in the presence of hydrogen chloride. [2] The method for producing bisphenol according to [1], wherein the reducing agent is a thiol. [3] The method for producing bisphenol according to [2], wherein the thiol is obtained by neutralizing a metal salt of the thiol with hydrochloric acid. [4] The content of the aldehyde in the ketone before the reduction step is more than 0 ppm by mass and less than 5.0 × 10 4 The method for producing bisphenol according to any one of [1] to [3], wherein the concentration is less than ppm by mass. [5] The method for producing bisphenol according to any one of [1] to [4], wherein the aldehyde is acetaldehyde and the ketone is acetone. [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 the step of producing a polycarbonate resin using bisphenol produced by the method for producing bisphenol according to any one of [1] to [6]. Effect of the Invention

[0008] According to the production method of the present invention, a bisphenol having a good melt color can be provided by contacting a ketone previously treated with a reducing agent with an aromatic alcohol, and a method for producing a polycarbonate resin having a good color tone using the bisphenol can also be provided. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0009] The following is a detailed description of the embodiments of the present invention, 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 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.

[0010] 1. Bisphenol manufacturing method The first embodiment of the present invention is a method for producing bisphenol, which includes a reduction step of mixing a ketone containing an aldehyde with a reducing agent and reducing at least a part of the aldehyde, and a reaction step of reacting the ketone that has been reduced with an aromatic alcohol in the presence of hydrogen chloride. By this production method, bisphenol with a good melt color can be produced.

[0011] 1-1. Reduction process The reduction step in this embodiment is a step of mixing a ketone containing an aldehyde with a reducing agent to reduce at least a portion of the aldehyde. As shown in the examples described later, industrially produced ketones usually unavoidably contain an aldehyde. That is, in this specification, the concept of "aldehyde-containing ketone" includes industrially produced ketones such as commercially available ketone products, ketones produced on a laboratory scale according to known production methods, etc. In addition, "aldehyde-containing ketone" may be a ketone to which an aldehyde has been intentionally added.

[0012] As a result of intensive research, the present inventors have found that the aldehyde in the ketone and / or the bisphenol produced by the reaction of this aldehyde with an aromatic alcohol are the cause of the deterioration of color. Therefore, the inventors thought that a bisphenol with a good melt color could be obtained by reducing the amount of aldehyde and reducing the amount of substances causing the deterioration of color or suppressing their production prior to the reaction of the ketone with the aromatic alcohol. The reduction step is a step aimed at reducing the amount of aldehyde by allowing a reducing agent to act on a ketone containing an aldehyde to reduce the aldehyde to an alcohol.

[0013] Therefore, the amount of aldehyde reduced in the reaction step is preferably 10% by mass or more of the aldehyde contained in the ketone, more preferably 50% by mass or more, even more preferably 80% by mass or more, particularly preferably 90% by mass or more, and most preferably the total amount. The amount of aldehyde reduced can be calculated by measuring the content in the ketone before and after the reduction step by gas chromatography. The reagents used in this step, the procedure, and the reaction conditions are described below.

[0014] (Ketone) Ketones are usually compounds represented by the following general formula (1).

[0015] [ka]

[0016] In the general formula (1), R 5and R 6 are each independently an alkyl group, an aryl group, or R 5 and R 6 and are bonded together with the adjacent carbon atoms to form a cycloalkylidene group. The alkyl group is preferably an alkyl group having 1 to 12 carbon atoms, and more preferably an alkyl group having 1 to 6 carbon atoms.

[0017] Specific examples of the compound represented by the general formula (1) include dialkyl 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; cyclic alkane ketones such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, and cyclododecanone; and the like. Of these, the ketone is preferably a dialkyl ketone, and more preferably acetone. The ketone may be used alone or in any combination and ratio of two or more.

[0018] (aldehyde) Ketones contain one or more aldehydes. Ketones inevitably contain aldehydes derived from the ketones, but may contain other aldehydes. Aldehydes are represented by the above general formula (1), R 5 and R 6 are each independently a hydrogen atom, an alkyl group or an aryl group, and 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.

[0019] Specific examples of the aldehyde include formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, pentanaldehyde, hexanealdehyde, heptanealdehyde, octanaldehyde, nonanealdehyde, decanaldehyde, undecanealdehyde, dodecanealdehyde, benzaldehyde, etc. For example, when the ketone is acetone, the aldehyde usually includes acetaldehyde and / or propylenealdehyde derived from acetone.

[0020] The content of the aldehyde in the ketone to be subjected to the reduction step is not particularly limited, but is usually more than 0 ppm by mass, and may be 5 ppm by mass or more, 10 ppm by mass or more, 20 ppm by mass or more, 25 ppm by mass or more, or more than 25 ppm by mass. The upper limit of the content of the aldehyde in the ketone to be subjected to the reduction step is usually 5.0 × 10 4 Mass ppm or less, preferably 5.0 x 10 3 Mass ppm or less, more preferably 5.0×10 2 ppm by mass or less, more preferably 5.0×10 1 As described above, since aldehyde is a substance that causes coloration, even if the amount of aldehyde is reduced in the reduction step, the content of aldehyde in the ketone is preferably low in order to produce bisphenol with good melt color, that is, the content of aldehyde in the ketone is preferably within the above range. The content of aldehyde in ketone is quantitatively determined by gas chromatography as shown in the examples described later.

[0021] (reducing agent) The reducing agent used in the reduction step is not particularly limited as long as it can reduce a part or all of the aldehyde contained in the ketone and does not reduce the ketone. Examples of such reducing agents include thiol, oxalic acid, formic acid, hypophosphite, sulfite, and the like. However, in this embodiment, if thiol, oxalic acid, formic acid, and the like are selected as the reducing agent, it is possible to suppress the coloring of the target bisphenol without using a strong inorganic reducing agent such as sodium hypophosphite used in Patent Document 2. In addition, among the above-mentioned reducing agents, thiol can also function as a co-catalyst in the reaction step described below, so it is not necessarily necessary to remove the thiol that remains without being used in the reduction reaction before the reaction step. Therefore, it is preferable to use thiol as the reducing agent not only from the viewpoint of improving the color tone of bisphenol but also from the viewpoint of work efficiency and reaction efficiency in the reaction step.

[0022] Examples of thiols include alkanethiols such as methanethiol, ethanethiol, 1-propanethiol, 2-propanethiol, 1-butanethiol, 2-butanethiol, 2-methyl-1-propanethiol, 1,1-dimethylethanethiol, 1-pentanethiol, 1-hexanethiol, 1-heptanethiol, 1-octanethiol, 1-nonanethiol, 1-decanethiol, 1-undecanethiol, 1-dodecanethiol, 1-tridecanethiol, 1-tetradecanethiol, and 1-pentadecanethiol; cycloalkanethiols such as cyclopentanethiol and cyclohexanethiol; and the like. Among these, the thiol is preferably an alkanethiol, more preferably an alkanethiol having 1 to 20 carbon atoms, and even more preferably an alkanethiol having 1 to 12 carbon atoms. The thiols may be used alone or in any combination and ratio of two or more kinds.

[0023] The thiol may be a commercially available product or may be produced according to a known method. The latter thiol may be, for example, a product obtained by neutralizing a metal salt of thiol with hydrochloric acid. The metal salt of thiol may preferably be the alkali metal salt of thiol described above.

[0024] Examples of hypophosphites include sodium hypophosphite, potassium hypophosphite, calcium hypophosphite, magnesium hypophosphite, and ammonium hypophosphite. Examples of sulfites include sodium sulfite, potassium sulfite, and ammonium sulfite.

[0025] The amount of the reducing agent used in the reaction step is not particularly limited as long as it can convert a part or all of the aldehyde in the ketone into an alcohol, and may be appropriately selected depending on the type of aldehyde, the type of reducing agent, etc. Specifically, the amount of the reducing agent used is such that the mass ratio of the reducing agent to the aldehyde is usually 500 or more, preferably 800 or more, more preferably 1000 or more, and usually 5000 or more. The molecular weight average molecular weight is preferably 1,000 or less, more preferably 4,000 or less, more preferably 3,000 or less, and even more preferably 2,000 or less. By making the amount of the reducing agent to be used equal to or more than the above lower limit, the amount of aldehyde is sufficiently reduced, and bisphenol having a good melt color can be obtained. In addition, when the amount of the reducing agent used is equal to or less than the above upper limit, the reaction mixture can be directly subjected to the reaction step without removing the reducing agent remaining unused in the reduction reaction from the reaction mixture, which provides advantages in terms of production cost and work efficiency. In this specification, when two or more types of each component used in the calculation are used, the terms "amount used," "mass ratio," "molar ratio," etc. are meant to be values ​​calculated using the total amount thereof.

[0026] (Operation procedure and reaction conditions) The method for mixing the aldehyde-containing ketone and the reducing agent is not particularly limited, and can be carried out by a known method, for example, a method in which they are placed in a reactor equipped with stirring means such as a stirrer or stirring blade and stirred.

[0027] The reaction temperature in the reduction step is not particularly limited, but from the viewpoint of sufficiently reducing the amount of aldehyde, it is usually 0°C or higher, preferably 10°C or higher, preferably 15°C or higher, and more preferably 20°C, and from the viewpoint of suppressing the volatilization of ketones and thiols, it is usually 50°C or lower, preferably 40°C or lower. The reaction time in the reduction step is not particularly limited as long as at least a part of the aldehyde in the ketone is reduced, and may be appropriately selected depending on the type of aldehyde, the type of reducing agent, the reaction temperature, etc. Specifically, the reaction time is usually 10 minutes or more, preferably 30 minutes or more, more preferably 1 hour or more, and usually 24 hours or less, preferably 10 hours or less, more preferably 5 hours or less.

[0028] Here, when using a thiol obtained by neutralizing a metal salt of thiol with hydrochloric acid as a reducing agent, the thiol produced by neutralizing a metal salt of thiol with hydrochloric acid in advance may be mixed with a ketone containing an aldehyde according to the above-mentioned procedure, or a reduction step may be carried out by mixing a ketone containing an aldehyde, a metal salt of thiol, and hydrochloric acid. In the latter case, in a mixed solution containing a ketone containing an aldehyde, the metal salt of thiol is neutralized with hydrochloric acid to generate a thiol, and the ketone containing an aldehyde and the thiol are mixed. At this time, the generation of thiol from the metal salt of thiol proceeds stoichiometrically quickly, so the range of the amount of thiol used described above can be applied as the amount of the metal salt of thiol used as it is. In addition, the reaction conditions described above can be applied as the reaction conditions.

[0029] 1-2.Reaction process The reaction step in this embodiment is a step of reacting the ketone that has been subjected to the reduction step with an aromatic alcohol in the presence of hydrogen chloride to produce a bisphenol. The bisphenol produced is usually a compound represented by the following general formula (2).

[0030] [ka]

[0031] R 1 ~R 4 Each of the groups independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, R is selected from the group consisting of a silyl 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. 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 the aryloxy group include an n-butyloxy group, 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.

[0032] R 5 and R 6 is R in the above general formula (1). 5 and R 6 It is synonymous with that in.

[0033] 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)propane, 2,2-bis(4-hydroxyphenyl)propane, 2,2-bis(4-hydroxyphenyl)cyclohexane ... Examples of such hydroxyphenyl compounds include, but are not limited to, 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.

[0034] 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).

[0035] (Aromatic alcohol) The aromatic alcohol used in the production of bisphenol is usually a compound represented by the following general formula (3).

[0036] [ka]

[0037] 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.

[0038] 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.

[0039] 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, phenylphenol, etc. Among these, the aromatic alcohol is preferably one other than xylenol, more preferably selected from phenol and cresol, and even more preferably cresol. The aromatic alcohols may be used alone or in any combination of two or more in any ratio.

[0040] 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.

[0041] (Hydrogen Chloride) In the reaction step of this embodiment, hydrogen chloride is used as a catalyst for the condensation reaction of the ketone and the aromatic alcohol. Hydrogen chloride may be added to the reaction system in the form of an aqueous solution (hydrochloric acid), or may be introduced into the reaction system in the form of hydrogen chloride gas by bubbling or the like.

[0042] When hydrogen chloride is used in a form other than hydrogen chloride gas, if the molar ratio of hydrogen chloride to ketone (moles of hydrogen chloride / moles of ketone) is low, hydrogen chloride is diluted with water by-produced as the condensation reaction proceeds, and the reaction takes time. If the ratio is high, the ketone may polymerize or the generated bisphenol may decompose. For these reasons, the molar ratio of hydrogen chloride to ketone used in the condensation reaction 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.

[0043] (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 co-catalyst, for example in the production of 2,2-bis(4-hydroxy-3-methylphenyl)propane, the production of 2,4'-isomer (2-(2-hydroxy-3-methylphenyl)-2-(4-hydroxy-3-methylphenyl)propane) is suppressed, and the selectivity of 4,4'-isomer (2,2-bis(4-hydroxy-3-methylphenyl)propane) is increased, while the polymerization activity during the production of polycarbonate resin is enhanced. The reason for this effect of improving the polymerization activity during the production of polycarbonate resin is that the use of a thiol reduces the production of inhibitors for the polymerization reaction that produces polycarbonate resin. It is presumed that this is because the synthesis is suppressed. As described above, the thiol used as the reducing agent in the reduction step can also function as a co-catalyst in the reaction step. Therefore, when a thiol is used as the reducing agent in the reduction step, the above-mentioned polymerization activity improvement effect can be obtained by the thiol remaining without being used in the reduction reaction, even if a thiol is not added to the reaction system in the reaction step.

[0044] Examples of thiols used as promoters 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. Thiols may be used alone or in any combination and ratio of two or more.

[0045] 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.

[0046] (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 bisphenols, which are the products, 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. The organic solvents may be used alone or in any combination and ratio of two or more.

[0047] Examples of aromatic hydrocarbons include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and mesitylene. After being used in the production of bisphenol, aromatic hydrocarbons can be recovered and purified by distillation or the like and reused. When aromatic hydrocarbons are reused, those with a low boiling point are preferred. One of the preferred aromatic hydrocarbons is toluene.

[0048] 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.

[0049] 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 more preferably an alcohol having an alkyl group having 1 to 5 carbon atoms and one hydroxy group bonded thereto. Alcohol is more preferred.

[0050] 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.

[0051] 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.

[0052] 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.

[0053] 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. In this specification, "room temperature" refers to a temperature range of 15 to 35°C. 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.

[0054] (Operation Procedure) The method for preparing the reaction liquid in the reaction step is not particularly limited, and examples thereof include a method in which an aromatic alcohol, hydrogen chloride, and, if necessary, a thiol, an organic solvent, and the like are stirred in a reactor equipped with a stirring means such as a stirrer or stirring blade, and the ketone that has undergone the reduction step is supplied to the obtained mixed liquid; a method in which the ketone that has undergone the reduction step, the aromatic alcohol, and the organic solvent are mixed, and then hydrogen chloride is further mixed therein; and the like. Alternatively, the reaction may be controlled by mixing all the raw materials at a low temperature and then gradually increasing the temperature to a temperature at which the reaction producing bisphenol occurs.

[0055] (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.

[0056] 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.

[0057] 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 nitrogen, carbon dioxide, and argon atmospheres.

[0058] 1-3. Purification process The production method according to this embodiment may include a production step of further purifying the bisphenol produced in the reaction step. 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 liquid is washed with water, saline, etc., and further neutralized and washed with sodium bicarbonate water, etc., as necessary. Next, the washed organic phase is 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.

[0059] 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.

[0060] 1-4. 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.

[0061] 2. Polycarbonate resin manufacturing method The second embodiment of the present invention is a method for producing a polycarbonate, comprising a step of producing a polycarbonate resin using the bisphenol produced by the production method according to the first embodiment of the present invention. 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, in the production of the polycarbonate resin, bisphenol may be used alone or two or more kinds may be used in any combination and ratio. By using two or more kinds of bisphenol, a copolymer polycarbonate resin can be produced. It is also possible to react the aryl group with a dihydroxy compound other than the aryl group. 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.

[0062] 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] 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.

[0067] 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

[0068] 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.

[0069] [Raw materials and reagents] In the following examples and comparative examples, orthocresol, toluene, sodium hydroxide, 35% by mass hydrochloric 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. The 15% by mass aqueous solution of sodium methyl mercaptan was a reagent manufactured by Tokyo Chemical Industry Co., Ltd. Diphenyl carbonate used was a product manufactured by Mitsubishi Chemical Corporation.

[0070] [Analysis method] <Measurement of the amount of aldehyde in ketone> The analysis of aldehydes in ketones was carried out by gas chromatography under the following procedures and conditions.

[0071] Equipment: Shimadzu Corporation "GC-2014" Column: Agilent Technologies DB-FFAP, inner diameter 0.53 mm, length 60 m, film thickness 1.0 μm 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

[0072] <Bisphenol composition analysis> The compositional analysis of bisphenol was carried out by high performance liquid chromatography according to the following procedure and conditions.

[0073] Equipment: Shimadzu Corporation "LC-2010A" Column: Intact Corporation "Scherzo SM-C18", inner diameter 3 μm, length 250 mm, 3.0 mm ID 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. The analysis was performed at a flow rate of 0.34 mL / min.

[0074] <Measurement of pH> The measurement of pH was carried out at a liquid temperature of 25 °C using a pH meter "pH METER ES-73" manufactured by Horiba, Ltd.

[0075] <Electrical conductivity> The measurement of electrical conductivity was carried out at a liquid temperature of 25 °C using a conductivity meter "COND METER D-71" manufactured by Horiba, Ltd.

[0076] <Melt color of bisphenol> The melt color of bisphenol was evaluated by putting 20 g of bisphenol 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 measuring its Hazen color number using a spectrocolorimeter "SE6000" manufactured by Nippon Denshoku Industries Co., Ltd.

[0077] <Viscosity-average molecular weight> The viscosity-average molecular weight (Mv) of the polycarbonate resin was calculated 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 using the following formula. ηsp / C = [η](1 + 0.28ηsp) [η] = 1.23×10 -4 Mv 0.83

[0078] <Pellet YI> Pellet YI (transparency of polycarbonate resin) was evaluated by measuring the YI value (yellow index value) in the reflected light of polycarbonate resin pellets in accordance with ASTM D1925. The apparatus used was a spectrocolorimeter "CM-5" manufactured by Konica Minolta Japan, Inc., and the measurement conditions were a measurement diameter of 30 mm and SCE (specular component excluded) 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 pellet 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 for the evaluation.

[0079] <Example 1> (1-1) Production of bisphenol C A separable flask equipped with a thermometer, a dropping funnel, a jacket, and an anchor-type stirring blade was charged with 5 g of toluene and 230 g of ortho-cresol 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, a reduction step was carried out. Specifically, 2 g of dodecanethiol and 65 g of acetone were placed in an Erlenmeyer flask and stirred at 25° C. for 1 hour to prepare a mixed solution B1. The obtained mixed solution B1 was placed in a dropping funnel. Subsequently, the reaction step was carried out. Specifically, while stirring the mixed solution A1 at 25° C., the mixed solution B1 in the dropping funnel was dropped into the mixed solution A1 over 1 hour, and the reaction solution was further stirred for 2 hours at 30° C. to obtain a reaction mixture C1 containing bisphenol C.

[0080] 290 g of 25% sodium hydroxide solution and 250 g of toluene were added to the reaction mixture C1 containing bisphenol C, and the mixture was heated to 75° C. with stirring, and then demineralized water was added to completely dissolve the remaining sodium chloride produced by neutralization. The resulting mixture was left to stand to separate the oil and water, and the aqueous phase was removed from the separable flask to obtain an organic phase D1. A 3% by weight sodium bicarbonate solution was added to the organic phase D1 maintained at 75° C. and neutralized by stirring. The resulting mixture was left to stand to separate into oil and water, and then the aqueous phase was removed from the separable flask to obtain an organic phase E1. The organic phase E1 was gradually cooled from 75° C. to 5° C. to precipitate bisphenol C-containing crystals, which were then subjected to solid-liquid separation by vacuum filtration to obtain 220 g of a bisphenol C-containing cake.

[0081] In a separable flask equipped with a thermometer, a jacket, and an anchor-type stirring blade, 220 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 heated to 75°C. The resulting mixture was left to stand to separate the oil and water, and the aqueous phase (hereinafter referred to as "aqueous phase 1") was removed from the separable flask to obtain an organic phase F1. The pH of the aqueous phase 1 was 8.6, and the electrical conductivity was 152 μS / cm.

[0082] 100 g of demineralized water was added to the obtained organic phase F1 and stirred for 30 minutes. The obtained mixture was left to stand for oil-water separation, and then the aqueous layer (hereinafter referred to as "aqueous phase 2") was removed from the separable flask to obtain organic phase G1. The electrical conductivity of aqueous phase 2 was 73 μS / cm. The operation of washing organic phase G1 with 100 g of demineralized water was repeated until the electrical conductivity of the aqueous phase after washing was 10 μS / cm or less, to obtain organic phase H1. The organic phase H1 was gradually cooled from 75° C. to 5° C. to precipitate bisphenol C-containing crystals, which were then subjected to solid-liquid separation by vacuum filtration to obtain 182 g of a bisphenol C-containing cake.

[0083] 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., yielding 147 g of a white solid. A portion of the resulting white solid was sampled and subjected to the composition analysis described above, confirming that the product was bisphenol C.

[0084] (1-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (1-1) was measured and found to be 15 on the Hazen color scale.

[0085] (1-3) Color tone of polycarbonate resin In a glass reaction vessel having a capacity of 150 mL and equipped with a stirrer and a distillation tube, 100.00 g (0.39 mol) of bisphenol C obtained in (1-1), 86.49 g (0.4 mol) of diphenyl carbonate, and 480 μL of an aqueous cesium carbonate solution having a concentration of 400 ppm by mass 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.

[0086] 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 by the oligomerization reaction of bisphenol C and 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 discharged outside 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.

[0087] 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. Next, the polycarbonate resin was extracted in a strand form from the bottom of the reactor to obtain a strand-shaped polycarbonate resin. Then, the strand was 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.

[0088] <Example 2> (2-1) Production of bisphenol C In the reduction step, a white solid was obtained in the same manner as in (1-1), except that a mixture B1 was prepared by adding 35% by mass hydrochloric acid to a mixture obtained by putting 4.6 g of a 15% by mass aqueous solution of sodium methyl mercaptan and 65 g of acetone into a Schlenk flask equipped with a stirrer, and stirring the mixture for 1 hour at 25° C. A part of the obtained white solid was sampled, and the composition analysis described above was performed to confirm that the product was bisphenol C.

[0089] (2-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (2-1) was measured and found to be 18 on the Hazen color scale.

[0090] (2-3) Color tone of polycarbonate resin A polycarbonate resin was produced in the same manner as in (1-3), except that the bisphenol C obtained in (2-1) was used instead of the bisphenol C obtained in (1-1). The YI of the obtained polycarbonate resin pellets was 8.4.

[0091] <Comparative Example 1> (A-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 A2. Next, 65 g of acetone was placed in the dropping funnel as ketone liquid B2. Next, while stirring the mixed liquid A2 while maintaining the temperature at 25°C, the ketone liquid B2 in the dropping funnel was dropped into the mixed liquid A2 over 1 hour, and the reaction liquid was stirred for an additional 2 hours while maintaining the temperature at 30 to obtain a reaction mixture. The product was then purified in the same manner as in (1-1) to obtain a pale yellow solid. A portion of the obtained pale yellow solid was sampled and subjected to the above-mentioned composition analysis, confirming that the product was bisphenol C.

[0092] (A-2) Color of Bisphenol C The melt color of the bisphenol C obtained in (A-1) was measured and found to be 25 on the Hazen color scale.

[0093] (A-3) Color tone of polycarbonate resin A polycarbonate resin was produced in the same manner as in (1-3), except that the bisphenol C obtained in (A-1) was used instead of the bisphenol C obtained in (1-1). The resulting polycarbonate resin pellets had a YI of 9.6.

[0094] In Examples 1 and 2 and Comparative Example 1, the amount of acetaldehyde in the acetone used, the location where the thiol was supplied, the mass ratio of the thiol to the acetaldehyde in the acetone, the melt color of the obtained bisphenol C, and the obtained polycarbonate resin pellets YI are summarized in Table 1.

[0095] [Table 1]

[0096] From Table 1, it can be seen that bisphenol with good melt color can be obtained by reacting acetone containing acetaldehyde with thiol in advance and then mixing with orthocresol (Examples 1 and 2). It can also be seen that polycarbonate resin with good color tone can be obtained by using bisphenol C obtained in this way as a raw material (Examples 1 and 2).

Claims

1. a reduction step of mixing a ketone containing an aldehyde with a reducing agent to reduce at least a portion of the aldehyde; and a reaction step of reacting the ketone having been subjected to the reduction step with an aromatic alcohol in the presence of hydrogen chloride, The content of the aldehyde in the ketone before the reduction step is more than 0 ppm by mass and 5.0 × 10 4 ppm by mass or less; A method for producing bisphenol, wherein a mass ratio of the reducing agent to the aldehyde is 500 or more and 5,000 or less.

2. The method for producing bisphenol according to claim 1, wherein the reducing agent is a thiol.

3. The method for producing bisphenol according to claim 2, wherein the thiol is obtained by neutralizing a metal salt of the thiol with hydrochloric acid.

4. The method for producing bisphenol according to any one of claims 1 to 3, wherein the aldehyde is acetaldehyde and the ketone is acetone.

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

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

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