阅读说明：本技术 双酚组合物和聚碳酸酯树脂 (Bisphenol composition and polycarbonate resin ) 是由 内山馨 横木正志 柴田浩喜 富田空 矢山裕一 鹤原谦二 吉田隆之 中岛幸惠 小西利惠 于 2020-02-26 设计创作，主要内容包括：一种双酚组合物,其含有95质量％以上的双酚,该双酚组合物中的下述通式(II)所表示的双酚的含量为150质量ppm以上,该双酚组合物的甲醇溶解色(Hazen色值)为2以下。一种聚碳酸酯树脂的制造方法,其使用了该双酚组合物。通式(II)中,X为单键、-CR～(11)R～(12)-、-O-、-CO-、-S-、-SO-或-SO-(2)-。R～(11)、R～(12)各自独立地为氢原子或者碳原子数1～10的烷基。R～(11)和R～(12)可以键合形成环。(A bisphenol composition containing 95 mass% or more of bisphenol, wherein the bisphenol composition has a bisphenol content represented by the following general formula (II) of 150 mass ppm or more, and the bisphenol composition has a methanol-soluble color (Hazen color value) of 2 or less. A method for producing a polycarbonate resin, which uses the bisphenol composition. In the general formula (II), X is a single bond, -CR 11 R 12 -, -O-, -CO-, -S-, -SO-or-SO 2 ‑。R 11 、R 12 Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R 11 And R 12 May be bonded to form a ring.)

1. A bisphenol composition comprising 95% by mass or more of bisphenol,

the bisphenol composition has a bisphenol content represented by the following general formula (II) of 150 mass ppm or more,

the bisphenol composition has a methanol-soluble color (Hazen color value) of 2 or less,

[ solution 1]

In the general formula (II), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-；R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; r¹¹And R¹²May be bonded to form a ring.

2. The bisphenol composition according to claim 1, wherein the bisphenol is a bisphenol represented by the following general formula (I),

[ solution 2]

In the general formula (I), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-；R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; r¹¹And R¹²May be bonded to form a ring.

3. The bisphenol composition according to claim 1 or 2, wherein the content of the bisphenol represented by the general formula (II) in the bisphenol composition is 20000 mass ppm or less.

4. The bisphenol composition according to any one of claims 1 to 3, wherein the bisphenol represented by the general formula (II) is at least one selected from the group consisting of 2- (4-hydroxy-3-methylphenyl) -2- (4-hydroxy-3, 5-dimethylphenyl) propane, 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) cyclohexane and 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) -3,3, 5-trimethylcyclohexane.

5. The bisphenol composition according to any of claims 1 to 4, wherein the bisphenol composition is melted at 190 ℃ for 30 minutes, and has a Hazen color number of 100 or less as measured by "SE 6000" manufactured by Nippon Denshoku industries Ltd.

6. The bisphenol composition of any of claims 1-5, wherein the sodium content of the bisphenol composition is less than 0.5 mass ppm.

7. The bisphenol composition according to any one of claims 1 to 6, wherein the iron content in the bisphenol composition is 0.5 ppm by mass or less.

8. The bisphenol composition according to any one of claims 1 to 7, wherein the content of aluminum in the bisphenol composition is 0.1 ppm by mass or less.

9. The bisphenol composition according to any one of claims 1 to 8, wherein the bisphenol represented by general formula (I) is at least one selected from the group consisting of 2, 2-bis (4-hydroxy-3-methylphenyl) propane, 1-bis (4-hydroxy-3-methylphenyl) cyclohexane, and 1, 1-bis (4-hydroxy-3-methylphenyl) -3,3, 5-trimethylcyclohexane.

10. The method for producing a bisphenol composition according to any one of claims 1 to 9, wherein the bisphenol represented by the general formula (II) is by-produced in the production of bisphenol.

11. A method for producing a polycarbonate resin, which comprises using the bisphenol composition according to any one of claims 1 to 9.

12. A polycarbonate resin having at least a repeating structural unit represented by the following general formula (A), wherein a compound obtained by subjecting the polycarbonate resin to alkali hydrolysis contains a bisphenol represented by the following general formula (I) and a bisphenol represented by the following general formula (II), and the amount of the bisphenol represented by the following general formula (II) obtained by alkali hydrolysis is 160 ppm by mass or more relative to the polycarbonate resin,

[ solution 3]

In the general formula (A), R¹～R⁶Each independently is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, or an aryl group, and the alkyl group, the alkoxy group, or the aryl group may be any of substituted or unsubstituted groups; r⁵And R⁶The two radicals being able to be bonded or crosslinked to one another, R⁵And R⁶May also be bonded together with adjacent carbon atoms to form a cycloalkylidene group which may contain heteroatoms;

[ solution 4]

In the general formula (I), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-；R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; r¹¹And R¹²May be bonded to form a ring;

[ solution 5]

In the general formula (II), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-；R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms; r¹¹And R¹²May be bonded to form a ring.

13. The polycarbonate resin according to claim 12, wherein the bisphenol represented by the general formula (II) is 20000 mass ppm or less with respect to the polycarbonate resin.

14. The polycarbonate resin according to claim 12 or 13, which has a viscosity average molecular weight of 15000 or more and 35000 or less.

Technical Field

The present invention relates to a bisphenol composition, a polycarbonate resin and a method for producing the same.

The bisphenol composition of the present invention can be used as a raw material for resins such as polycarbonate resin, epoxy resin, aromatic polyester resin, etc., or additives such as a curing agent, a color developer, an anti-fading agent, other bactericides, an antibacterial and antifungal agent, etc.

Background

Bisphenols are used as raw materials for high polymer materials such as polycarbonate resins, epoxy resins, aromatic polyester resins, and the like. As typical bisphenols, for example, 2-bis (4-hydroxyphenyl) propane and 2, 2-bis (4-hydroxy-3-methylphenyl) propane are known (patent documents 1 and 2).

Patent document 1: japanese laid-open patent publication No. 62-138443

Patent document 2: japanese patent laid-open No. 2014-40376

Polycarbonate resins, which are typical uses of bisphenols, are required to be colorless and transparent. The color tone of the polycarbonate resin is significantly affected by the color tone of the raw material. Therefore, it is required that the color tone of bisphenol as a raw material is also colorless.

Since it is difficult to directly quantify the color of bisphenol, in the present invention, bisphenol is dissolved in methanol and the color difference is quantified, and this color tone is referred to as "methanol-dissolved color".

In the production of a polycarbonate resin, particularly in the melting method, bisphenol is melted to produce a polycarbonate resin, and therefore, it is exposed to high temperature. Thus, bisphenols are also required to have color tone stability against heat.

In the present invention, this hue is referred to as "color difference in melting".

In the production of polycarbonate resins, since bisphenol is melted and then subjected to polymerization reaction, it is also required to have color tone stability against heat until the polymerization is started.

In the present invention, this hue is referred to as "thermal hue stability".

In the production of polycarbonate resins, when bisphenol is thermally decomposed before the start of polymerization, the amount of substance of bisphenol decreases, and the amount of substance of bisphenol deviates from the amount of substance of diphenyl carbonate, which is a raw material, by a predetermined amount of substance, and thus a polycarbonate resin having a desired molecular weight cannot be obtained, and thus bisphenol is also required to have stability against heat.

In the present invention, this stability is referred to as "thermal decomposition stability".

As for the polycarbonate resin, a polycarbonate resin having a molecular weight in accordance with design and a good color tone is being sought. In order to produce such a polycarbonate resin, bisphenol as a raw material is required to have excellent methanol dissolution color, color difference in melting, and thermal hue stability, and also excellent thermal decomposition stability.

Disclosure of Invention

The invention aims to provide a bisphenol composition with good methanol dissolution color, color difference of melting, thermal color tone stability and thermal decomposition stability. The present invention also aims to provide a polycarbonate resin having excellent color tone using the bisphenol composition.

The present inventors have found that a bisphenol C composition containing a specific compound at a predetermined ratio is excellent in methanol-soluble color, color difference in melting, thermal hue stability, and thermal decomposition stability. The present inventors have also found that a polycarbonate resin containing a structural unit derived from the specific compound at a predetermined ratio is excellent in color tone.

That is, the gist of the present invention lies in the following [1] to [14 ].

[1] A bisphenol composition containing 95 mass% or more of bisphenol, wherein the bisphenol composition has a content of bisphenol represented by the following general formula (II) of 150 mass ppm or more, and the bisphenol composition has a methanol-soluble color (Hazen color value) of 2 or less.

[ solution 1]

In the general formula (II), X represents a single bond, -CR¹¹R¹²-、-O-、-CO-、-S-、-SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

[2] The bisphenol composition according to [1], wherein the bisphenol is a bisphenol represented by the following general formula (I).

[ solution 2]

In the general formula (I), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

[3] The bisphenol composition as described in [1] or [2], wherein the content of the bisphenol represented by the general formula (II) is 20000 mass ppm or less.

[4] The bisphenol composition according to any one of [1] to [3], wherein the bisphenol represented by the general formula (II) is at least one selected from the group consisting of 2- (4-hydroxy-3-methylphenyl) -2- (4-hydroxy-3, 5-dimethylphenyl) propane, 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) cyclohexane and 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) -3,3, 5-trimethylcyclohexane.

[5] The bisphenol composition according to any one of [1] to [4], wherein the bisphenol composition is melted at 190 ℃ for 30 minutes, and has a Hazen color value of 100 or less as measured by "SE 6000" manufactured by Nippon Denshoku industries Ltd.

[6] The bisphenol composition according to any one of [1] to [5], wherein the sodium content in the bisphenol composition is less than 0.5 mass ppm.

[7] The bisphenol composition according to any one of [1] to [6], wherein the iron content in the bisphenol composition is 0.5 mass ppm or less.

[8] The bisphenol composition according to any one of [1] to [7], wherein the aluminum content in the bisphenol composition is 0.1 mass ppm or less.

[9] The bisphenol composition according to any one of [1] to [8], wherein the bisphenol represented by the general formula (I) is at least one selected from the group consisting of 2, 2-bis (4-hydroxy-3-methylphenyl) propane, 1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 1, 1-bis (4-hydroxy-3-methylphenyl) -3,3, 5-trimethylcyclohexane.

[10] The process for producing a bisphenol composition according to any one of [1] to [9], wherein the bisphenol represented by the general formula (II) is produced as a by-product in the production of bisphenol.

[11] A method for producing a polycarbonate resin, which comprises using the bisphenol composition according to any one of [1] to [9 ].

[12] A polycarbonate resin having at least a repeating structural unit represented by the following general formula (A), wherein a compound obtained by subjecting the polycarbonate resin to alkali hydrolysis contains a bisphenol represented by the following general formula (I) and a bisphenol represented by the following general formula (II), and the amount of the bisphenol represented by the following general formula (II) obtained by alkali hydrolysis is 160 ppm by mass or more relative to the polycarbonate resin.

[ solution 3]

In the general formula (A), R¹～R⁶Each independently is a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group or an aryl group, and the alkyl group, the alkoxy group or the aryl group may be any of substituted or unsubstituted groups. R⁵And R⁶The two radicals being able to be bonded or crosslinked to one another, R⁵And R⁶Or may be bonded together with adjacent carbon atoms to form a cycloalkylidene group which may contain heteroatoms.

[ solution 4]

In the general formula (I), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

[ solution 5]

In the general formula (II), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

[13] The polycarbonate resin according to [12], wherein the bisphenol represented by the general formula (II) is 20000 mass ppm or less based on the polycarbonate resin.

[14] The polycarbonate resin as described in [12] or [13], which has a viscosity average molecular weight of 15000 to 35000 inclusive.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the present invention, a bisphenol composition having excellent methanol solubility, color difference in melting, thermal hue stability and thermal decomposition stability is provided by containing a specific compound in a predetermined ratio.

According to the present invention, a polycarbonate resin having an excellent color tone can be provided by a polycarbonate resin obtained using the bisphenol composition, that is, a polycarbonate resin obtained by hydrolyzing the bisphenol composition with an alkali to obtain the specific compound at a predetermined ratio.

Detailed Description

The embodiments of the present invention will be described in detail below. The following description of the constituent elements is an example of the embodiment of the present invention, and the present invention is not limited to the following description as long as the elements do not exceed the gist thereof.

In the present specification, the expression "to" is used as an expression including numerical values and physical property values before and after the expression.

[ bisphenol composition ]

The bisphenol composition of the present invention is a bisphenol composition containing 95% by mass or more of bisphenol, and is characterized in that the content of bisphenol represented by the following general formula (II) (hereinafter sometimes referred to as "bisphenol (II)") in the bisphenol composition is 150 ppm by mass or more, and the methanol dissolution color (Hazen color value) of the bisphenol composition is 2 or less.

[ solution 6]

In the general formula (II), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

The content of bisphenol (II) in the bisphenol composition of the present invention is preferably 200 mass ppm or more, more preferably 250 mass ppm or more, particularly preferably 300 mass ppm or more, preferably 20000 mass ppm or less, more preferably 15000 mass ppm or less, further preferably 1400 mass ppm or less, particularly preferably 1300 mass ppm or less.

When the content of bisphenol (II) in the bisphenol composition is less than the above lower limit, a bisphenol composition having good methanol solubility color, difference in melting color, thermal hue stability, and thermal decomposition stability cannot be obtained. When the content of bisphenol (II) in the bisphenol composition is more than the above upper limit, the following tendency is exhibited.

1) When a polycarbonate resin is produced, the molar ratio of diphenyl carbonate to the polycarbonate resin varies, and the polymerization reaction is affected.

2) This causes a reduction in brittleness (IZOD) of a polycarbonate resin obtained using the bisphenol composition, or a reduction in high surface hardness which is peculiar to a polycarbonate resin containing a structural unit derived from bisphenol (I) described later.

Specific examples of bisphenol (II) include at least one selected from the group consisting of 2- (4-hydroxy-3-methylphenyl) -2- (4-hydroxy-3, 5-dimethylphenyl) propane, 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) cyclohexane, and 1- (4-hydroxy-3-methylphenyl) -1- (4-hydroxy-3, 5-dimethylphenyl) -3,3, 5-trimethylcyclohexane. Among these, 2- (4-hydroxy-3-methylphenyl) -2- (4-hydroxy-3, 5-dimethylphenyl) propane (hereinafter referred to as "trimethylbisphenol A") is particularly preferable.

Detection and quantification of bisphenol (II) can be carried out using a standard high-speed analytical reversed-phase column having a particle size of 3 μm.

The content of bisphenol (II) in the bisphenol composition can be adjusted by adding an appropriate amount of bisphenol (II) to bisphenol which is not contained or contains bisphenol (II) at a low concentration after purification. Further, as described later, bisphenol (II) may be produced together with bisphenol in the reaction system at the time of production of bisphenol, and a bisphenol product containing bisphenol (II) may be produced as the bisphenol composition of the present invention.

< bisphenol >

The bisphenol contained in the bisphenol composition of the present invention is generally a compound represented by the following general formula (1).

[ solution 7]

R in the general formula (1)¹～R⁶And R in the following general formulae (3) and (4)¹Preferable examples of the compounds having the same meaning as R include those described in the following general formulae (3) and (4).

Specific examples of the bisphenol represented by the above general formula (1) include 2, 2-bis (4-hydroxyphenyl) propane, 2-bis (4-hydroxy-3-methylphenyl) propane, 2-bis (4-hydroxy-3, 5-dimethylphenyl) propane, 1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 1-bis (4-hydroxy-3-methylphenyl) -3,3, 5-trimethylcyclohexane, 9-bis (4-hydroxy-3-methylphenyl) fluorene, 3-bis (4-hydroxyphenyl) pentane, 3-bis (4-hydroxy-3-methylphenyl) pentane, 2-bis (4-hydroxy-3-methylphenyl) propane, 2-bis (4-hydroxy-3, 5-dimethylphenyl) propane, 1-bis (4-hydroxy-3-methylphenyl) cyclohexane, 3, 5-trimethylcyclohexane, 9-bis (4-hydroxy-3-methylphenyl) fluorene, 3-bis (4-hydroxyphenyl) pentane, 3-bis (4-hydroxy-3-methylphenyl) pentane, 2-bis (4-hydroxy-3-methylphenyl) propane, 2-methyl-propane, 9-propane, 2-bis (4-hydroxy-3-methylphenyl) propane, 9-3-methyl-fluorene, 9-fluorene, 3-bis (4-methyl-phenyl) pentane, 3-one or more, 2, 2-bis (4-hydroxyphenyl) pentane, 2-bis (4-hydroxy-3-methylphenyl) pentane, 3-bis (4-hydroxyphenyl) heptane, 3-bis (4-hydroxy-3-methylphenyl) heptane, 2-bis (4-hydroxyphenyl) heptane, 2-bis (4-hydroxy-3-methylphenyl) heptane, 4-bis (4-hydroxyphenyl) heptane, 4-bis (4-hydroxy-3-methylphenyl) heptane and the like, but are not limited in any way by these substances.

Among them, as the bisphenol contained in the bisphenol composition of the present invention, a bisphenol represented by the following general formula (I) (hereinafter, sometimes referred to as "bisphenol (I)") is preferable. The bisphenol (I) is preferably at least one selected from the group consisting of 2, 2-bis (4-hydroxy-3-methylphenyl) propane, 1-bis (4-hydroxy-3-methylphenyl) cyclohexane and 1, 1-bis (4-hydroxy-3-methylphenyl) -3,3, 5-trimethylcyclohexane. 2, 2-bis (4-hydroxy-3-methylphenyl) propane (bisphenol C) is particularly preferred.

[ solution 8]

In the general formula (I), X represents a single bond, -CR¹¹R¹²-, -O-, -CO-, -S-, -SO-or-SO₂-。R¹¹、R¹²Each independently represents a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. R¹¹And R¹²May be bonded to form a ring.

In the bisphenol composition of the present invention, such bisphenol is contained in an amount of 95% by mass or more, preferably 99% by mass or more, and more preferably 99.5% by mass or more. If the content of bisphenol is less than the above lower limit, it is not preferable for use as bisphenol. The upper limit of the content of bisphenol in the bisphenol composition of the present invention is usually about 99.9 mass% in terms of securing the content of bisphenol (II), production cost, adjustment of the mass ratio to diphenyl carbonate in the production reaction of the polycarbonate resin, mechanical properties of the polycarbonate resin such as surface hardness and brittleness, and the like.

Detection and quantification of bisphenols may be performed using a standard high-speed analytical reversed-phase column.

< color of bisphenol composition dissolved in methanol >

The methanol-soluble color of the bisphenol composition was used to evaluate the color tone of the bisphenol composition at ordinary temperature. The lower the Hazen color number of the methanol-soluble color of the bisphenol composition, the better (closer to white) the hue of the bisphenol composition. The reason why the methanol-soluble color of the bisphenol composition is deteriorated is that an organic coloring component or a metal is mixed in.

The methanol-soluble color of the bisphenol composition was measured as follows: the bisphenol composition was dissolved in methanol to prepare a homogeneous solution, and then the measurement was carried out at room temperature (about 20 ℃ C.). The measurement method includes: a method of comparing with a standard solution of Hazen color value by visual observation; or a method of measuring the Hazen color value by using a color difference meter such as "SE 6000" manufactured by Nippon Denshoku industries Co., Ltd. The mass ratio of the solvent methanol, bisphenol and solvent used herein is preferably selected as appropriate depending on the type of bisphenol.

The Hazen color value of the methanol-soluble color of the bisphenol composition of the present invention is 2 or less, preferably 1 or less, and more preferably 0 or less.

< color difference in melting of bisphenol composition >

The color difference of the melt of the bisphenol composition was evaluated for the color tone of the bisphenol composition at a temperature close to the polymerization temperature of the polycarbonate. The measurement temperature of the difference in melting point was the melting point of bisphenol +50 ℃. The lower the Hazen color number of the color difference in melting of the bisphenol composition, the better the hue (closer to white) of the bisphenol composition. The reason for the deterioration of the color difference of melting of the bisphenol composition is not only the mixing of an organic coloring component or a metal but also a component colored by heating.

The color difference in melting of the bisphenol composition is measured by melting the bisphenol composition at a temperature close to the polymerization temperature and stabilizing the temperature for a predetermined period of time. The measurement method includes: a method of comparing with a standard solution of Hazen color value by visual observation; or a method of measuring the Hazen color value by using a color difference meter such as "SE 6000" manufactured by Nippon Denshoku industries Co., Ltd.

The bisphenol composition of the present invention is melted at 190 ℃ for 30 minutes, and the Hazen color number measured using "SE 6000" manufactured by Nippon Denshoku industries Co., Ltd is preferably 100 or less, more preferably 30 or less, particularly preferably 25 or less, and particularly preferably 20 or less.

< thermal color tone stability of bisphenol composition >

The thermal color tone stability of the bisphenol composition was evaluated by keeping the composition at a temperature close to the polymerization temperature of the polycarbonate for a predetermined time, similarly to the color difference of the melt of the bisphenol composition. The temperature at which the thermal color tone stability of the bisphenol composition is measured is the melting point of bisphenol +50 ℃.

With respect to the thermal tone stability of the bisphenol composition, a lower Hazen color number indicates a better thermal tone stability of the bisphenol composition. The reason why the thermal color tone stability of the bisphenol composition is deteriorated is that, in addition to the mixing of the organic coloring component or the metal, a component colored by heating or an acidic substance or a basic substance having a concentration of about several ppm may be cited.

The thermal color stability of the bisphenol composition was measured by melting the bisphenol composition at a temperature close to the polymerization temperature and stabilizing the composition at the temperature for a predetermined period of time. The retention time of the thermal color tone stability of the bisphenol composition was 4 hours. The measurement method includes: a method of comparing with a standard solution of Hazen color value by visual observation; or a method of measuring the Hazen color value by using a color difference meter such as "SE 6000" manufactured by Nippon Denshoku industries Co., Ltd.

The Hazen color number is preferably 50 or less, more preferably 45 or less, and particularly preferably 35 or less.

< thermal decomposition stability of bisphenol composition >

The thermal decomposition stability of the bisphenol composition was evaluated by keeping the bisphenol composition at a temperature close to the polymerization temperature of the polycarbonate for a predetermined time period, similarly to the thermal hue stability of the bisphenol composition. The preferred measurement temperature for the thermal decomposition stability of the bisphenol composition is the melting point of bisphenol +50 ℃. Regarding the thermal decomposition stability of the bisphenol composition, the smaller the amount of the decomposition product produced, the more stable the bisphenol composition.

The decomposition product in the thermal decomposition stability of the bisphenol composition depends on the kind of bisphenol, and examples thereof include an aromatic alcohol as a raw material of the bisphenol composition, and an adduct of the aromatic alcohol and a ketone or an aldehyde as a raw material. The reason why the thermal color tone stability of the bisphenol composition is deteriorated is that, in addition to the mixing of the organic coloring component or the metal, a component colored by heating or an acidic substance or a basic substance having a concentration of about several ppm may be cited.

The detection and quantification of the decomposition products of the bisphenol composition can be carried out using a standard reverse phase column for high-speed analysis.

The amount of isopropenylcresol formed as a decomposition product of the bisphenol composition, as measured in examples described later, is preferably 200 mass ppm or less.

The methanol-soluble color of the bisphenol composition is a method for evaluating the color tone of the bisphenol composition itself. In the case where the bisphenol composition is a final product, a bisphenol composition having a good methanol-soluble color is important. Since polycarbonate resins have the color tone of the raw material, bisphenol compositions having a good color tone are important for polycarbonate resins which are required to have colorless transparency.

In the melt polymerization method, which is one of the methods for producing a polycarbonate resin, since a polymerization reaction is carried out at a high temperature, the color tone of a bisphenol composition at the time of melting (color difference of melting of the bisphenol composition) and the color tone stability of the bisphenol composition in a molten state (thermal color tone stability of the bisphenol composition) are important.

Further, in this melt polymerization method, the bisphenol composition is kept in a molten state at a high temperature until the polymerization reaction starts. In this melt polymerization method, when the bisphenol composition is decomposed at a high temperature, the ratio of the substance to the diphenyl carbonate deviates from a predetermined ratio of the substance, and it is difficult to obtain a polycarbonate resin having a predetermined molecular weight and a polymerization activity. Therefore, resistance to thermal decomposition (thermal decomposition stability of the bisphenol composition) is important.

In particular, in order to produce a polycarbonate resin having a predetermined molecular weight and a good color tone, the methanol-soluble color of a bisphenol composition, the color difference of a bisphenol composition in melting, the thermal color tone stability of a bisphenol composition, and the thermal decomposition stability of a bisphenol composition are important.

< sodium content in bisphenol composition >

The sodium content in the bisphenol composition of the present invention is preferably less than 0.5 mass ppm, more preferably less than 0.4 mass ppm, and particularly preferably less than 0.3 mass ppm. Sodium in the bisphenol composition exhibits a catalytic action, and therefore, if its content is large, thermal hue stability and thermal decomposition stability are deteriorated. Therefore, the sodium content in the bisphenol composition of the present invention is preferably not more than the above upper limit.

The sodium content in the bisphenol composition was measured by the method described in the following examples.

< iron content in bisphenol composition >

The iron content in the bisphenol composition of the present invention is preferably 0.5 mass ppm or less, more preferably 0.4 mass ppm or less, and particularly preferably 0.3 mass ppm or less. The iron in the bisphenol composition has a structure in which the bisphenol is coordinated, and therefore has absorption in the visible region. Therefore, the iron causes coloring of the bisphenol composition, and if the content thereof is large, the methanol-soluble color and the color difference of melting are deteriorated. In addition, since the iron exhibits a catalytic action, if the content thereof is large, the thermal hue stability and the thermal decomposition stability are deteriorated. Therefore, the iron content in the bisphenol composition of the present invention is preferably not more than the above upper limit.

Examples of the source of iron in the bisphenol composition of the present invention include iron dissolved in an aromatic alcohol as a raw material of bisphenol, iron mixed from a reaction tank or a facility above the reaction tank at the time of reaction for producing bisphenol, and the like. These iron are suitably removed by a purification method described later, such as repeated washing under acidic conditions or repeated washing under alkaline conditions, depending on the form of iron.

The iron content of the bisphenol composition was measured by the method described in the following examples.

< aluminum content in bisphenol composition >

The content of aluminum in the bisphenol composition of the present invention is preferably 0.1 mass ppm or less, more preferably 0.09 mass ppm or less, and particularly preferably 0.08 mass ppm or less. The aluminum in the bisphenol composition has a structure in which bisphenol is coordinated, and therefore has absorption in the visible region. Therefore, the aluminum causes coloring of the bisphenol composition, and if the content thereof is large, the methanol-dissolved color and the color difference of melting are deteriorated. Further, since the aluminum exhibits a catalytic action, when the content thereof is large, the thermal color tone stability and the thermal decomposition stability are deteriorated. Therefore, the content of aluminum in the bisphenol composition of the present invention is preferably not more than the above upper limit.

Examples of the source of aluminum in the bisphenol composition of the present invention include aluminum dissolved in an aromatic alcohol which is a raw material of bisphenol, aluminum derived from alumina which is mixed from the outside in the removal operation after obtaining a solid of bisphenol or in the supply to a dryer, and the like. These aluminum can be removed by a purification method described later, such as repeated washing under acidic conditions or repeated washing under alkaline conditions, depending on the form of aluminum.

The aluminum content in the bisphenol composition was measured by the method described in the following examples.

< method for producing bisphenol composition >

The method for producing the bisphenol composition of the present invention containing 95 mass% or more of bisphenol (preferably bisphenol (I)) and bisphenol (II) in a predetermined ratio is not particularly limited, and the following methods can be exemplified.

(1) Method for adding predetermined amount of bisphenol (II) to solid bisphenol (I)

(2) Method for adding predetermined amount of bisphenol (II) to molten bisphenol (I)

(3) Method for producing bisphenol (I) by-producing bisphenol (II) or producing bisphenol (II) together with bisphenol (I) to obtain bisphenol (I) product containing bisphenol (II)

In the methods (1) and (2) of adding bisphenol (II) to solid or molten bisphenol (I), it is necessary to separately prepare bisphenol (II). Therefore, (3) a method of by-producing bisphenol (II) in the reaction system for producing bisphenol (I) or a method of producing bisphenol (II) and containing bisphenol (II) in a predetermined ratio in the bisphenol (I) product is preferable.

In the case where the amount of bisphenol (II) by-produced or produced in the reaction system for bisphenol (I) is too large, the control may be performed as follows: the bisphenol (I) product obtained is further purified by crystallization, suspension cleaning, spray cleaning, or the like to remove a part of bisphenol (II) contained in the bisphenol (I) product, thereby obtaining a bisphenol (I) product containing bisphenol (II) within the specified range of the present invention.

< method for obtaining bisphenol C product containing bisphenol (II) >

Hereinafter, a method for producing the bisphenol composition of the present invention mainly containing a predetermined amount of bisphenol (II) and mainly bisphenol (I) will be described by way of example, with reference to trimethyl bisphenol a as a typical example of bisphenol (II) and bisphenol C as a typical example of bisphenol (I).

As a method for producing bisphenol C and trimethyl bisphenol a in the reaction system to produce bisphenol C and trimethyl bisphenol a simultaneously in the production of bisphenol C to obtain a bisphenol C product containing trimethyl bisphenol a as the bisphenol composition of the present invention, there is a method for producing bisphenol C or bisphenol C and trimethyl bisphenol a by condensing a ketone or aldehyde with an aromatic alcohol in the presence of an acid catalyst and a thiol promoter. By this method, trimethyl bisphenol A can be produced in the reaction system.

The method is explained below.

In this method, bisphenol C is produced by condensing an aromatic alcohol with a ketone or an aldehyde in the presence of an acid catalyst.

The bisphenol formation reaction proceeds according to the following general reaction scheme (2). In the present invention, in such a bisphenol production reaction, the raw material aromatic alcohol and the raw material ketone or aldehyde are selectively used so that at least bisphenol C is produced.

[ solution 9]

In the formula, R¹～R⁶The same as in the general formula (1).

(aromatic alcohol)

The aromatic alcohol used as a raw material for producing bisphenol is generally a compound represented by the following general formula (3).

[ solution 10]

In the general formula (3), as R¹～R⁴Each independently includes a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. The alkyl group, alkoxy group, aryl group, and the like may be any of substituted or unsubstituted groups. As R¹～R⁴Examples thereof 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 isopropyl group, a n-butyl group, an isobutyl group, a tert-butyl group, a n-pentyl group, an isopentyl 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 isopropoxy group, a n-butoxy group, an isobutoxy group, a tert-butoxy group, a n-pentoxy group, an isopentoxy group, a n-hexoxy group, a n-heptoxy group, a n-octoxy group, a n-nonoxy group, a n-decoxy group, a n-undecyloxy group, a n-dodecoxy 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, a2, 6-dimethylphenyl group and the like.

Among these, R is preferable because the condensation reaction is difficult when the steric bulk is large²And R³Is a hydrogen atom. More preferably R¹～R⁴Each independently is a hydrogen atom or an alkyl group. Further preferred is R¹、R⁴Each independently is a hydrogen atom or an alkyl group, R²、R³Is a hydrogen atom.

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

In the present invention, at least o-cresol of these is used to produce bisphenol C, or o-cresol is used together with xylenol to produce bisphenol C and trimethyl bisphenol A.

(Ketone or aldehyde)

The ketone or aldehyde used as a raw material for producing bisphenol is generally a compound represented by the following general formula (4).

[ solution 11]

In the general formula (4), as R⁵And R⁶Each independently includes a hydrogen atom, an alkyl group, an alkoxy group, an aryl group, and the like. The alkyl group, alkoxy group, aryl group, and the like may be any of substituted or unsubstituted groups. As R⁵、R⁶Examples thereof include a hydrogen atom, methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, tert-butyl group, n-pentyl group, isopentyl group, n-hexyl group, n-heptyl group, n-octyl group, 2-ethylhexyl group, n-nonyl group, n-decyl group, n-undecyl group, n-dodecyl group, methoxy group, ethoxy group, n-propoxy group, isopropoxy group, n-butoxy group, isobutoxy group, tert-butoxy group, n-pentoxy group, isopentoxy group, n-hexoxy group, n-heptoxy group, n-octoxy group, n-nonoxy group, n-decoxy group, n-undecyloxy group, n-dodecoxy group, cyclopropyl group, cyclobutyl group, cyclopentyl group, cyclohexyl group, cycloheptyl group, cyclooctyl group, cyclododecyl group, benzyl group, phenyl group, tolyl group, 2, 6-dimethylphenyl group and the like.

R⁵And R⁶These two groups may be bonded or crosslinked to each other. R⁵And R⁶Or may be bonded together with adjacent carbon atoms to form a cycloalkylidene group which may contain heteroatoms. Cycloalkylidene is a 2-valent radical obtained by removing 2 hydrogen atoms from one carbon atom of a cycloalkane.

As R⁵And R⁶Examples of the cycloalkylidene group which is bonded together with the adjacent carbon atom include cyclopropylidene, cyclobutylidene, cyclopentylidene, cyclohexylidene, 3, 5-trimethylcyclohexylidene, cycloheptylidene, cyclooctylidene, cyclononylidene, cyclodecylidene, cycloundecylidene, cyclododecylidene, fluorenylidene, xanthonylidene and thioxanthone-ylidene.

Specific examples of the compound represented by the general formula (4) include aldehydes such as formaldehyde, acetaldehyde, propionaldehyde, butyraldehyde, valeraldehyde, caproaldehyde, heptaldehyde, caprylic aldehyde, nonanal, decanal, undecanal, and dodecanal; ketones such as acetone, butanone, pentanone, hexanone, heptanone, octanone, nonanone, decanone, undecanone, and dodecanone; aralkyl ketones such as benzaldehyde, phenylmethyl ketone, phenylethyl ketone, phenylpropyl ketone, tolylmethyl ketone, tolylethyl ketone, tolylpropyl ketone, ditolyl methyl ketone, ditolyl ethyl ketone, and ditolyl propyl ketone, cyclic alkane ketones such as cyclopropanone, cyclobutanone, cyclopentanone, cyclohexanone, cycloheptanone, cyclooctanone, cyclononanone, cyclodecanone, cycloundecanone, and cyclododecanone; and so on.

In the present invention, at least acetone among these compounds is used.

In the condensation reaction of an aromatic alcohol with a ketone or an aldehyde, if the molar ratio of the aromatic alcohol to the ketone or the aldehyde is small, the ketone or the aldehyde multimerizes; if the molar ratio is too high, the aromatic alcohol does not react and is lost. For these reasons, the molar ratio of the aromatic alcohol to the ketone or the aldehyde is preferably 1.5 or more, more preferably 1.6 or more, further preferably 1.7 or more, preferably 15 or less, more preferably 10 or less, further preferably 8 or less.

The method of feeding the ketone and the aldehyde may employ a method of feeding at once as well as a method of feeding in batches. Since the reaction to produce bisphenol is an exothermic reaction, it is preferable to add the ketone and the aldehyde dropwise at a little by little and to supply them in divided portions.

(acid catalyst)

Examples of the acid catalyst used for producing bisphenol include an aromatic sulfonic acid such as sulfuric acid, hydrochloric acid, hydrogen chloride gas, phosphoric acid, p-toluenesulfonic acid, and an aliphatic sulfonic acid such as methanesulfonic acid.

When the molar ratio of the acid catalyst to the ketone or aldehyde used in the condensation is small ((the number of moles of the acid catalyst/the number of moles of the ketone) or (the number of moles of the acid catalyst/the number of moles of the aldehyde)), the acid catalyst is diluted with water by-produced as the condensation reaction proceeds, and the reaction takes time. When the molar ratio is large, polymerization of ketone or aldehyde may proceed. For these reasons, the molar ratio of the acid catalyst to the ketone or aldehyde used in the condensation is preferably 0.01 or more, more preferably 0.05 or more, further preferably 0.1 or more, preferably 10 or less, more preferably 8 or less, further preferably 5 or less.

The acid catalyst is preferably any one selected from the group consisting of sulfuric acid, hydrochloric acid, hydrogen chloride gas, aromatic sulfonic acids such as phosphoric acid and p-toluenesulfonic acid, aliphatic sulfonic acids such as methanesulfonic acid, and the like.

When the molar ratio of hydrogen chloride to the ketone or aldehyde used in the reaction is small ((the number of moles of hydrogen chloride/the number of moles of ketone) or (the number of moles of hydrogen chloride/the number of moles of aldehyde)), hydrogen chloride is diluted with water by-produced in the condensation reaction, and it is necessary to prolong the reaction time. When the molar ratio is large, polymerization of ketone or aldehyde may proceed. For these reasons, the molar ratio of hydrogen chloride to the ketone or aldehyde is preferably 0.01 or more, more preferably 0.05 or more, further preferably 0.1 or more, preferably 10 or less, more preferably 8 or less, further preferably 5 or less.

The sulfuric acid is of the formula H₂SO₄The acid liquid indicated. Sulfuric acid is generally used in the form of an aqueous sulfuric acid solution diluted with water, and is called concentrated sulfuric acid or dilute sulfuric acid depending on its concentration. For example, the dilute sulfuric acid is an aqueous sulfuric acid solution having a mass concentration of less than 90 mass%.

When the concentration of the sulfuric acid used (concentration of the aqueous sulfuric acid solution) is low, the amount of water increases, so that the reaction for producing bisphenol C is difficult to proceed, the reaction time for producing bisphenol is prolonged, and it may be difficult to efficiently produce bisphenol. Therefore, the concentration of the sulfuric acid used is preferably 70% by mass or more, more preferably 75% by mass or more, and further preferably 80% by mass or more. The upper limit of the concentration of the sulfuric acid used is usually 99.5 mass% or less or 99 mass% or less.

(mercaptan)

In the production of bisphenols, thiols can be used as a catalyst promoter in the condensation reaction of ketones or aldehydes with aromatic alcohols.

By using a thiol as a catalyst promoter, for example, in the production of 2, 2-bis (4-hydroxy-3-methylphenyl) propane, the effect of suppressing the formation of 24-mer and increasing the selectivity for 44-mer can be obtained, and the effect of improving the polymerization activity in the production of a polycarbonate resin and improving the color tone of the obtained polycarbonate resin can be obtained.

The reason why the effect of improving the polymerization activity in the production of a polycarbonate resin and improving the color tone of the obtained polycarbonate resin is exerted is not clear in detail, but it is presumed that the use of a thiol can suppress the generation of a blocking substance to the polymerization reaction for producing a polycarbonate resin and the generation of a color tone deterioration product.

Examples of the mercaptan used as the catalyst auxiliary include mercaptocarboxylic acids such as thioglycolic acid, 2-mercaptopropionic acid, 3-mercaptopropionic acid, and 4-mercaptobutyric acid; alkyl mercaptans such as methyl mercaptan, ethyl mercaptan, propyl mercaptan, butyl mercaptan, pentyl mercaptan, hexyl mercaptan, heptyl mercaptan, octyl mercaptan, nonyl mercaptan, decyl mercaptan (decyl mercaptan), undecyl mercaptan (undecyl mercaptan), dodecyl mercaptan (dodecyl mercaptan), tridecyl mercaptan, tetradecyl mercaptan, and pentadecyl mercaptan; aryl thiols such as mercaptophenol; and so on.

When the molar ratio of the thiol promoter to the ketone or aldehyde used for condensation is small (the number of moles of the thiol promoter/the number of moles of the ketone or (the number of moles of the thiol promoter/the number of moles of the aldehyde)), the effect of improving the reaction selectivity of bisphenol by using the thiol promoter cannot be obtained. When the molar ratio is large, the bisphenol may be mixed with the bisphenol to deteriorate the quality. For these reasons, the molar ratio of the thiol promoter to the ketone and the aldehyde is preferably 0.001 or more, more preferably 0.005 or more, further preferably 0.01 or more, preferably 1 or less, more preferably 0.5 or less, further preferably 0.1 or less.

The thiol promoter is preferably premixed with the ketone or aldehyde prior to being provided for reaction. As for the method of mixing the thiol with the ketone or the aldehyde, the ketone or the aldehyde may be mixed in the thiol, and the thiol may also be mixed in the ketone or the aldehyde.

As for the method of mixing the mixed solution of the thiol and the ketone or the aldehyde and the acid catalyst, the acid catalyst may be mixed with the mixed solution of the thiol and the ketone or the aldehyde, or the mixed solution of the thiol and the ketone or the aldehyde may be mixed with the acid catalyst, and it is preferable to mix the mixed solution of the thiol and the ketone or the aldehyde with the acid catalyst. More preferably, the acid catalyst and the aromatic alcohol are supplied to the reaction tank, and then the mixed solution of the thiol and the ketone or the aldehyde is supplied to the reaction tank and mixed.

(organic solvent)

In the production of bisphenols, an organic solvent is generally used in order to dissolve or disperse the bisphenol produced.

The organic solvent is not particularly limited insofar as it does not inhibit the bisphenol C production reaction, and examples thereof include aromatic hydrocarbons, aliphatic alcohols, and aliphatic hydrocarbons. Here, the aromatic alcohol as the raw material (based-pouenin) and the bisphenol as the product are not included in the organic solvent. These solvents may be used alone, or 2 or more kinds thereof may be used in combination.

Examples of the aromatic hydrocarbon include benzene, toluene, xylene, ethylbenzene, diethylbenzene, isopropylbenzene, and trimethylbenzene. These solvents may be used alone, or 2 or more kinds thereof may be used in combination. The aromatic hydrocarbon may be recovered and purified by distillation or the like after use in the production of bisphenol, and reused. When the aromatic hydrocarbon is reused, the boiling point is preferably low. One of the preferred aromatic hydrocarbons is toluene.

The aliphatic alcohol is an alkyl alcohol in which an alkyl group is bonded to a hydroxyl group. The aliphatic alcohol may be a monohydric aliphatic alcohol in which 1 hydroxyl group is bonded to an alkyl group, or a polyhydric aliphatic alcohol in which 2 or more hydroxyl groups are bonded to an alkyl group. The alkyl group may be linear or branched, and may be unsubstituted or a part of carbon atoms of the alkyl group may be substituted with oxygen atoms.

When the number of carbon atoms of the aliphatic alcohol is large, lipophilicity increases, and mixing with sulfuric acid becomes difficult, and a monoalkyl sulfate described later is not easily produced, and therefore the number of carbon atoms is preferably 12 or less, more preferably 8 or less.

The aliphatic alcohol is preferably an alcohol in which an alkyl group is bonded to 1 hydroxyl group, more preferably an alcohol in which an alkyl group having 1 to 8 carbon atoms is bonded to 1 hydroxyl group, and still more preferably an alcohol in which an alkyl group having 1 to 5 carbon atoms is bonded to 1 hydroxyl group.

Specific examples of the aliphatic alcohol include methanol, ethanol, n-propanol, isopropanol, n-butanol, isobutanol, t-butanol, n-pentanol, isopentanol, n-hexanol, n-heptanol, n-octanol, n-nonanol, n-decanol, n-undecanol, n-dodecanol, ethylene glycol, diethylene glycol, and triethylene glycol. One of the preferred aliphatic alcohols is methanol.

Examples of the aliphatic hydrocarbon include straight-chain 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, cyclic hydrocarbons having 5 to 18 carbon atoms such as cyclohexane, cyclooctane and methylcyclohexane, and the like.

If the mass ratio of the organic solvent to the ketone or aldehyde used for condensation is too large ((mass of ketone/mass of organic solvent) or (mass of aldehyde/mass of organic solvent)), the ketone or aldehyde and the aromatic alcohol are less likely to react with each other, and a long time is required for the reaction. If the mass ratio is too small, polymerization of ketone or aldehyde is promoted, and the bisphenol to be produced may be cured. For these reasons, the mass ratio of the organic solvent to the ketone or aldehyde at the time of charging is preferably 0.5 or more, more preferably 1 or more, and on the other hand, preferably 100 or less, more preferably 50 or less.

When the bisphenol to be produced is not completely dissolved but dispersed in an organic solvent, decomposition of the bisphenol is less likely to occur. It is also preferable to use a solvent having low solubility for bisphenol, because the loss in recovering bisphenol from the reaction solution after the completion of the reaction (for example, loss in the filtrate in crystallization) can be reduced. Examples of the solvent having low solubility of bisphenol include aromatic hydrocarbons. Therefore, the organic solvent preferably contains aromatic hydrocarbons as a main component, and the aromatic hydrocarbons are contained in the organic solvent preferably at 55 mass% or more, more preferably at 70 mass% or more, and further preferably at 80 mass% or more.

When the acid catalyst contains sulfuric acid, the following effects can be obtained by including an aliphatic alcohol in the organic solvent: sulfuric acid reacts with aliphatic alcohol to form monoalkyl sulfate, which also has catalytic action. Therefore, in the case where the acid catalyst contains sulfuric acid, the organic solvent is preferably an organic solvent containing an aliphatic alcohol. An alkyl alcohol having 8 or less carbon atoms is preferred because the lipophilicity increases with an increase in the carbon number of the aliphatic alcohol, and it is difficult to mix with sulfuric acid and to form a monoalkyl sulfate.

By reacting sulfuric acid with an aliphatic alcohol to produce a monoalkyl sulfate in this manner, the acid strength of the acid catalyst can be controlled, and condensation (polymerization) and coloring of the raw material ketone or aldehyde can be suppressed. Therefore, the production of by-products can be suppressed and bisphenol with reduced coloration can be produced easily and efficiently.

When sulfuric acid is reacted with an aliphatic alcohol to produce a monoalkyl sulfate and the catalytic action thereof is also utilized, if the molar ratio of the aliphatic alcohol to the sulfuric acid (the number of moles of the aliphatic alcohol/the number of moles of the sulfuric acid) is small, condensation (polymerization) and coloring of the raw material ketone or aldehyde become remarkable. When the molar ratio is large, the sulfuric acid concentration decreases and the reaction becomes slow. For these reasons, the molar ratio of the aliphatic alcohol to the sulfuric acid is preferably 0.01 or more, more preferably 0.05 or more, further preferably 0.1 or more, preferably 10 or less, more preferably 5 or less, further preferably 3 or less.

For the above reasons, the organic solvent may be made an organic solvent containing, for example, an aromatic hydrocarbon and an aliphatic alcohol. The organic solvent may contain 1 to 95 mass% of an aromatic hydrocarbon and 0.1 to 10 mass% of an aliphatic alcohol.

(preparation of reaction solution)

The method for preparing the reaction solution is not particularly limited, and examples thereof include: a method of supplying an acid catalyst to a mixed solution of an aromatic alcohol, an organic solvent, a ketone, or an aldehyde; a method of supplying a ketone or an aldehyde to a mixed solution of an acid catalyst, an aromatic alcohol and an organic solvent.

In order to suppress the polymerization caused by the self-condensation of the ketone or aldehyde, it is preferable to mix a solution containing the aromatic alcohol, the acid catalyst and the organic solvent with a solution containing the ketone or aldehyde. In this case, the solution containing the ketone or aldehyde may be the ketone or aldehyde alone, or may contain a thiol or an organic solvent. The solution containing the ketone or aldehyde preferably contains a thiol.

(reaction conditions)

The bisphenol C production reaction is a condensation reaction, and if the reaction temperature of the production reaction is too high, oxidative decomposition of mercaptan is carried out; if the amount is too low, the reaction takes a long time. Therefore, the reaction temperature is preferably 0 ℃ to 50 ℃.

If the reaction time of the formation reaction is too long, the formed bisphenol is decomposed, and therefore the reaction time is preferably within 30 hours, more preferably within 25 hours, and still more preferably within 20 hours. The lower limit of the reaction time is usually 0.5 hour or more.

The reaction can be stopped by reducing the sulfuric acid concentration by adding water in an amount equal to or greater than the amount of the sulfuric acid used, or by adding an aqueous sodium hydroxide solution so that the sulfuric acid concentration is 45% by mass or less.

(refining)

The purification of the bisphenol C product obtained by the bisphenol C formation reaction 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 reaction solution is separated, and the obtained organic phase is washed with water, a salt solution or the like, and further neutralized and washed with sodium bicarbonate water or the like as necessary. The washed organic phase was then cooled and crystallized. In the case where the aromatic alcohol is used in a large amount, the remaining aromatic alcohol is distilled off by distillation before the crystallization, and then the crystallization is performed.

In the present embodiment, a bisphenol C product containing trimethyl bisphenol A is obtained as the bisphenol composition of the present invention by leaving trimethyl bisphenol A as a by-product in the bisphenol C production reaction system. Therefore, in the above-mentioned method for purifying a bisphenol C product, it is preferable to appropriately combine crystallization, suspension cleaning, spray cleaning, and the like, for example, and adjust the purification conditions so that a predetermined amount of trimethyl bisphenol a remains in the purified bisphenol C product.

(example of purification step)

As an example of the purification step suitable for the present invention, a method of purifying a bisphenol C product obtained by a condensation reaction by washing in a washing step and then precipitating in a crystallization step will be described below.

In this case, after the condensation reaction, the bisphenol C-containing organic phase obtained from the reaction solution is washed with deionized water, and the washed organic phase is cooled to crystallize. The washing was performed a plurality of times as follows. The crystallization can also be carried out a plurality of times.

< cleaning Process >

In the cleaning step, at least the following 1 st step and 2 nd step are performed.

Step 1: the bisphenol C-containing organic phase (O1) obtained in the reaction step was mixed with deionized water, and then phase-separated into a bisphenol C-containing organic phase (O2) and an aqueous phase (W1), and the aqueous phase (W1) was removed to obtain a bisphenol C-containing organic phase (O2).

And a2 nd step: the bisphenol C-containing organic phase (O2) obtained in the 1 st water washing step was mixed with deionized water, and then phase-separated into a bisphenol C-containing organic phase (O3) and an aqueous phase (W2), and the aqueous phase (W2) was removed to obtain a bisphenol C-containing organic phase (O3).

The step 1 is preferably performed so that the pH of the aqueous phase (W1) becomes 8.5 or more. The step 2 is preferably carried out so that the conductivity of the aqueous phase (W2) becomes 10. mu.S/cm.

The deionized water is water subjected to ion exchange treatment, pure water, or the like, and has a conductivity of 1.5. mu.S/cm or less.

The measurement temperature of the aqueous phase (W1) is preferably room temperature (20 to 30 ℃), for example, 25 ℃.

When the pH of the aqueous phase is less than 7, the aqueous phase may be washed with an alkaline substance such as sodium hydroxide or sodium hydrogencarbonate, and then washed again with water. The organic phase obtained after washing with an alkaline substance is washed again with water so that the pH of the aqueous phase becomes 8.5 or more. Here, the pH is preferably 8.5 or more, more preferably 9 or more, because the washing effect is low when the alkalinity of the aqueous phase (W1) is weak (pH is low). On the other hand, when the aqueous phase (W1) is strongly alkaline (pH is high), bisphenol C becomes a bisphenol C salt and the amount of loss during washing with water increases, and the upper limit of the pH of the aqueous phase (W1) is usually 14 or less, preferably 13 or less, and more preferably 12 or less.

The temperature for measuring the conductivity of the aqueous phase (W2) in the washing step 2 is preferably room temperature (20 to 30 ℃ C.), and for example, preferably 25 ℃.

The conductivity of the aqueous phase (W2) in the washing step 2 is preferably 10. mu.S/cm or less, more preferably 9. mu.S/cm or less, and still more preferably 8. mu.S/cm or less.

In the washing step, it is preferable that in the washing with water of the organic phase containing bisphenol C, the obtained aqueous phase is first made alkaline at a pH of not less than 8.5, and then the washing with water is repeated as necessary, and the obtained aqueous phase is subjected to the crystallization step after the electrical conductivity thereof reaches not more than 10. mu.S/cm.

The following bisphenol composition was obtained by performing deionized water-based washing so that the pH of the aqueous phase (W1) in the 1 st washing step was not less than the lower limit and the conductivity of the aqueous phase (W2) in the 2 nd washing step was not more than the upper limit: the polycarbonate resin can be produced with good color tone by highly removing impurities such as by-products, residual catalysts, and residual mercaptans in the product bisphenol, and with high polymerization efficiency when used as a raw material bisphenol of a polycarbonate resin. In particular, in a condensation reaction using a mercaptan as a catalyst promoter, acidic sulfonium (チオニウム) can be formed from the mercaptan, which is contained in the bisphenol composition and interferes with the polymerization reaction in the production of the polycarbonate resin; however, as described above, by performing the washing step in which the pH of the aqueous phase (W1) and the conductivity of the aqueous phase (W2) are controlled, sulfonium can be effectively removed and polymerization inhibition by sulfonium can be prevented.

The temperature in the cleaning step is preferably 90 ℃ or lower, particularly 85 ℃ or lower, and 50 ℃ or higher, particularly 55 ℃ or higher, in order to allow bisphenol to be efficiently precipitated by cooling in a crystallization step described later without evaporating the solvent. The 1-time washing time (the time for adding deionized water to the organic phase for mixing) is usually about 1-120 minutes.

< crystallization step >

The cooling temperature in the crystallization step is 10 to 120 ℃ lower than the temperature of the organic phase (O3) obtained in the washing step, preferably 40 ℃ or lower, particularly 30 ℃ or lower, and-20 ℃ or higher, particularly-10 ℃ or higher. By cooling the washed organic phase (O3) to such a temperature, the bisphenol composition can be efficiently precipitated.

The bisphenol composition precipitated in the crystallization step can be recovered by solid-liquid separation by filtration, centrifugation, decantation, or the like.

In the case of performing the above-mentioned cleaning step and crystallization step, it is also preferable to control the purification conditions so that bisphenol (II) remains in a predetermined ratio in the bisphenol composition obtained after purification.

< uses of bisphenol >

The bisphenol composition of the present invention can be used as a component, a curing agent, an additive, a precursor of the above resin, or the like of a polyether resin, a polyester resin, a polyarylate resin, a polycarbonate resin, a polyurethane resin, a various thermoplastic resin such as an acrylic resin, an epoxy resin, an unsaturated polyester resin, a phenol resin, a polybenzoxazine resin, a cyanate resin, or the like, which is used in various applications such as an optical material, a recording material, an insulating material, a transparent material, an electronic material, an adhesive material, a heat-resistant material, or the like. The bisphenol composition of the present invention is also useful as an additive for a color-developing agent, a fading inhibitor, a bactericide, an antifungal agent, and the like for a heat-sensitive recording material and the like.

The bisphenol composition of the present invention can provide good mechanical properties, and therefore is preferably used as a raw material (monomer) for a thermoplastic resin or a thermosetting resin, and more preferably used as a raw material for a polycarbonate resin or an epoxy resin. The bisphenol composition of the present invention is also preferably used as a color developer, and particularly more preferably used in combination with a leuco dye or a color change temperature adjuster.

[ polycarbonate resin ]

The polycarbonate resin of the present invention is a polycarbonate resin comprising: the polycarbonate resin is a polycarbonate resin having at least a repeating structural unit represented by the following general formula (a), and a compound obtained by subjecting the polycarbonate resin to alkali hydrolysis (hereinafter sometimes referred to as "alkali hydrolysate") contains bisphenol (I) and bisphenol (II), and bisphenol (II) obtained by alkali hydrolysis is 160 ppm by mass relative to the polycarbonate resin. The polycarbonate resin of the present invention can be produced using the bisphenol composition of the present invention.

[ solution 12]

In the general formula (A), R¹～R⁶The same as in the general formula (1).

When the content of bisphenol (II) in the alkali hydrolysate of the polycarbonate resin is less than the above lower limit with respect to the polycarbonate resin, a polycarbonate resin having a good color tone cannot be obtained.

The proportion of the bisphenol (II) to the polycarbonate resin is preferably 200 mass ppm or more, more preferably 300 mass ppm or more, preferably 20000 mass ppm or less, more preferably 15000 mass ppm or less.

The method for producing the polycarbonate resin of the present invention using the bisphenol composition of the present invention includes a method in which the bisphenol composition of the present invention and diphenyl carbonate or the like are subjected to an ester exchange reaction in the presence of an alkali metal compound and/or an alkaline earth metal compound.

The bisphenol composition of the present invention may contain only 1 kind of bisphenol (I), 2 or more kinds of bisphenol (I), or 1 or 2 or more kinds of bisphenol (I) and other bisphenols. By using 2 or more kinds of bisphenols, a copolymerized polycarbonate resin can be produced. In addition, the reaction may be carried out by using a dihydroxy compound other than the bisphenol composition of the present invention.

The transesterification reaction can be carried out by appropriately selecting a known method. An example of a method for producing a polycarbonate resin from the bisphenol composition of the present invention and diphenyl carbonate as raw materials will be described below.

In the above-mentioned method for producing a polycarbonate resin, diphenyl carbonate is preferably used in an excess amount relative to bisphenol in the bisphenol composition of the present invention. In view of the fact that the polycarbonate resin to be produced has fewer terminal hydroxyl groups and the polymer has excellent thermal stability, it is preferable to use a larger amount of diphenyl carbonate relative to bisphenol. From the viewpoint of a high transesterification reaction rate and easy production of a polycarbonate resin having a desired molecular weight, it is preferable to use a small amount of diphenyl carbonate relative to bisphenol. For these reasons, the amount of diphenyl carbonate used is usually 1.001 mol or more, preferably 1.002 mol or more, usually 1.3 mol or less, preferably 1.2 mol or less based on 1 mol of bisphenol.

The bisphenol composition of the present invention and diphenyl carbonate can be supplied as solid materials as a method for supplying raw materials, but it is preferable to supply one or both of them in a molten state and in a liquid state.

In the production of a polycarbonate resin by the transesterification reaction of diphenyl carbonate with bisphenol, a transesterification catalyst is generally used. In the above-mentioned method for producing a polycarbonate resin, an alkali metal compound and/or an alkaline earth metal compound is preferably used as the transesterification catalyst. One kind of these may be used, and two or more kinds may be used in any combination and ratio. It is preferable to use an alkali metal compound in terms of practicality.

The amount of the catalyst to be used is usually 0.05. mu. mol or more, preferably 0.08. mu. mol or more, more preferably 0.10. mu. mol or more, and usually 100. mu. mol or less, preferably 50. mu. mol or less, more preferably 20. mu. mol or less based on 1 mol of bisphenol or diphenyl carbonate.

When the amount of the catalyst used is in the above range, the polymerization activity required for producing a polycarbonate resin having a desired molecular weight can be easily obtained, and a polycarbonate resin having excellent flowability during molding, which is excellent in polymer color tone and in which excessive branching of the polymer does not occur, can be easily obtained.

In the production of a polycarbonate resin by the above method, it is preferable that the two raw materials are continuously supplied to a raw material mixing tank, and the obtained mixture and a transesterification catalyst are continuously supplied to a polymerization reactor.

In the production of a polycarbonate resin by the transesterification method, the two raw materials supplied to a raw material mixing tank are generally uniformly stirred and then supplied to a polymerization reactor to which a transesterification catalyst is added, to thereby produce a polymer.

In the production of a polycarbonate resin using the bisphenol composition of the present invention, the polymerization reaction temperature is preferably 80 ℃ or more, particularly 150 ℃ or more and 400 ℃ or less, particularly 350 ℃ or less. The polymerization time is suitably adjusted depending on the ratio of raw materials, the desired molecular weight of the polycarbonate resin, and the like. Since deterioration in quality such as deterioration in color tone becomes noticeable when the polymerization time is long, the polymerization time is preferably 10 hours or less, more preferably 8 hours or less. The lower limit of the polymerization time is usually 0.1 hour or more, or 0.3 hour or more.

The bisphenol composition of the present invention can produce a polycarbonate resin having good color tone and excellent transparency. For example, a polycarbonate resin having a viscosity average molecular weight (Mv) of 10000 or more, preferably 15000 or more and 100000 or less, preferably 35000 or less, and pellets YI10 or less, which has a good color tone and excellent transparency, can be produced in a short time.

Examples

The present invention will be described more specifically with reference to examples and comparative examples. The present invention is not limited to the following examples as long as it does not exceed the gist thereof.

[ starting materials and reagents ]

In the following examples and comparative examples, o-cresol, toluene, 2, 6-xylenol, sodium hydroxide, sulfuric acid, dodecanethiol, acetone, sodium bicarbonate, cesium carbonate, acetonitrile, dichloromethane, acetic acid, ammonium acetate, and a reagent manufactured by Wako pure chemical industries, Ltd.

As the cresol, Fuji film and a reagent manufactured by Wako pure chemical industries, a product manufactured by Lanxess corporation or a product manufactured by JFE chemical corporation were used.

Diphenyl carbonate was produced by Mitsubishi chemical corporation.

[ analysis ]

< analysis of the composition of bisphenol C-producing reaction solution, analysis of trimethyl bisphenol A in bisphenol C composition, and analysis of trimethyl bisphenol A in alkaline hydrolysis product of polycarbonate resin >

The analysis of the composition of the bisphenol C-forming reaction solution, the analysis of trimethyl bisphenol A in the bisphenol C composition, and the analysis of trimethyl bisphenol A in the alkaline hydrolysis product of the polycarbonate resin were carried out by high performance liquid chromatography in the following order and under the following conditions.

An apparatus: "LC-2010A" manufactured by Shimadzu corporation "

Imtakt ScherzoSM-C18 3μm 250mm×3.0mmID

Low pressure gradient method

Analysis temperature: 40 deg.C

Eluent composition:

solution A ammonium acetate: acetic acid: deionized water 3.000 g: 1mL of: 1L of solution

B, liquid ammonium acetate: acetic acid: acetonitrile: deionized water 1.500 g: 1mL of: 900 mL: 150mL of solution

At an analysis time of 0 min, the eluent composition was solution a: liquid B is 60: 40 (volume ratio, same as below)

Slowly changing into liquid A when the analysis time is 0-41.67 minutes: solution B is 10: 90,

keeping the liquid A in the following state for 41.67-50 minutes of analysis time: solution B is 10: 90,

the analysis was performed at a flow rate of 0.34 mL/min.

< preparation of analysis solution of trimethylbisphenol A in alkaline hydrolysis product of polycarbonate resin >

A100 mL Erlenmeyer flask equipped with a stirrer was charged with 0.5g of polycarbonate resin pellets and 5mL of methylene chloride to prepare a homogeneous solution. To this, 45mL of methanol was added, and 5mL of a 25% aqueous solution of sodium hydroxide was added. The Erlenmeyer flask is immersed in a water bath at 70-75 ℃ and stirred for 30 minutes. The Erlenmeyer flask was then removed from the water bath, neutralized with hydrochloric acid, and water and methanol were added to prepare an analytical solution as a homogeneous solution for high performance liquid chromatography.

< determination of molecular weight of trimethyl bisphenol A >

The molecular weight of trimethylbisphenol A was determined using high performance Liquid Chromatography Mass Spectrometry (LCMS). High performance Liquid Chromatography Mass Spectrometry (LCMS) was performed in the following order and conditions.

A separation device: "Agilent 1200" manufactured by Agilent Technologies Co., Ltd "

Imtakt ScherzoSM-C18 3μm 150mm×4.6mmID

Low pressure gradient method

Analysis temperature: 40 deg.C

Eluent composition:

solution A ammonium acetate: acetic acid: deionized water 3.000 g: 1mL of: 1L of solution

B, liquid ammonium acetate: acetic acid: acetonitrile 1.500 g: 1mL of: 1L of solution

At an analysis time of 0 min, the eluent composition was solution a: liquid B is 60: 40 (volume ratio, same as below)

And slowly changing the analysis time to A liquid when the analysis time is 0-25 minutes: solution B is 90: 10,

and when the analysis time is 25-30 minutes, maintaining the solution A: solution B is 90: 10,

the analysis was performed at a flow rate of 1.0 mL/min.

Detection wavelength: 280nm

Mass spectrometer: "Agilent LC/MS 6130" manufactured by Agilent Technologies Co., Ltd "

Ion source: using ESI (Positive/negative) AJS probes

< analysis of bisphenol C in bisphenol C composition >

The analysis of bisphenol C in the bisphenol C composition was performed in the same manner as in the composition of the reaction liquid for bisphenol C formation, the analysis of trimethyl bisphenol a in the bisphenol C composition, and the analysis of trimethyl bisphenol a in the alkali hydrolysate of the polycarbonate resin. In the bisphenol C composition produced in the present invention, the purity of bisphenol C in bisphenol is usually 99 mass% or more, and the amount of bisphenol other than bisphenol C produced is very small, and therefore the content of bisphenol C in the bisphenol C composition can be regarded as the bisphenol content.

< identification of isopropenylcresol >

The identification of isopropenylcresol was carried out using a gas chromatography mass spectrometer in the following order and conditions.

An apparatus: "Agilent 6890" manufactured by Agilent Technologies Inc "

Column: "DB-1 MS" (inner diameter 0.25 mm. times.30 m. times.0.25 μm) manufactured by Agilent Technologies Co., Ltd

Carrier gas: helium

Flow rate: 1cm per minute³

Injection port temperature: 280 deg.C

Interface temperature: 250 deg.C

Ion source temperature: 250 deg.C

Column warming mode: first at 50 ℃ for 3 minutes, then at 10 ℃ per minute to 320 ℃, at 280 ℃ for 5 minutes

< measurement of pH >

The pH was measured by using a pH meter "pH METERES-73" manufactured by horiba, Ltd., and measuring the 25 ℃ aqueous phase taken out from the flask.

< conductivity >

For the measurement of the electrical conductivity, a conductivity meter "COND METERD-71" manufactured by horiba, Ltd was used, and the measurement was performed on the aqueous phase at 25 ℃ taken out from the flask.

< color of bisphenol C composition dissolved in methanol >

Test tube made of Nippon Nitrosum for methanol-soluble color of bisphenol C composition10g of bisphenol C composition and 10g of methanol were added to prepare a homogeneous solution, and the Hazen color value was measured at room temperature (about 20 ℃ C.) using "SE 6000" manufactured by Nippon Denshoku industries Ltd.

< color difference in melting of bisphenol C composition >

Test tubes made of Nippon Nitrosum for the color difference in melting of bisphenol C composition20g of bisphenol C composition was added thereto, and the mixture was melted at 190 ℃ for 30 minutes using "S" manufactured by Nippon Denshoku industries LtdE6000 "the Hazen color value was measured for evaluation.

< thermal hue stability of bisphenol C composition >

Test tube made of Nippon Nitrosum for thermal hue stability of bisphenol C compositionTo this was added 20g of a bisphenol C composition, and the resulting mixture was melted at 190 ℃ for 4 hours, and the Hazen color value was measured by using "SE 6000" manufactured by Nippon Denshoku industries Co., Ltd.

< thermal decomposition stability of bisphenol C composition >

Test tube manufactured by Nippon Nitrosum for thermal decomposition stability of bisphenol C composition20g of the bisphenol C composition was added thereto, and the mixture was melted at 190 ℃ for 2 hours, and the amount of isopropenylcresol formed was measured and evaluated in the same manner as in the above-mentioned composition analysis of the bisphenol C formation reaction liquid.

< analysis of sodium, iron and aluminum in bisphenol C composition >

About 1g of bisphenol C composition was collected, added with sulfuric acid, and subjected to dry ashing. Then, hydrofluoric acid was added to the obtained sample, and the sample was dried. Thereafter, nitric acid and pure water were added thereto to dissolve them. The obtained sample was fixed to a constant volume, diluted appropriately, and sodium, iron, and aluminum in the bisphenol C composition were quantitatively measured using ICP-MS ("ELEMENT 2" manufactured by Thermo Fisher Scientific Co., Ltd.).

< viscosity average molecular weight >

The polycarbonate resin was dissolved in methylene chloride (concentration: 6.0g/L), the specific viscosity (. eta.sp) at 20 ℃ was measured using a Ubbelohde viscometer, and the viscosity average molecular weight (Mv) was calculated from the following formula.

ηsp/C＝[η](1+0.28ηsp)

[η]＝1.23×10^-4Mv^0.83

< pellet YI >

Regarding pellet YI (transparency of polycarbonate resin), the YI value (yellowness index value) of polycarbonate resin pellets under reflected light was measured in accordance with ASTM D1925, and the YI was evaluated. The apparatus used a spectrocolorimeter "CM-5" manufactured by Konika Meinenda, and the measurement conditions were selected to measure 30mm diameter and SCE.

The petri dish measurement calibration glass "CM-a 212" was inserted into the measurement portion, and the zero calibration cassette "CM-a 124" was covered from above to perform zero calibration, and then white calibration was performed using a built-in white calibration plate. Then, the measurement was performed using a 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.

YI was measured by filling pellets into a cylindrical glass container having an inner diameter of 30mm and a height of 50mm to a depth of about 40 mm. The pellets were taken out from the glass container and measured again, and this operation was repeated 2 times, and the average value of the measured values was used 3 times in total.

[ reference example 1]

85g of bisphenol C composition and 4.5g of sodium hydroxide were put into a 500mL eggplant-shaped flask equipped with a stirrer, a thermometer and a distillation apparatus, and the flask was immersed in an oil bath heated to 195 ℃. After confirming that bisphenol C in the eggplant-shaped flask was melted, the pressure in the flask was gradually reduced using a vacuum pump to complete the vacuum. After a short time, evaporation was started and distillation was carried out under reduced pressure until the end of distillation. The obtained fraction was a mixture of cresol and isopropenylcresol, which were produced by thermal decomposition of bisphenol C, as seen by gas chromatography using a mass spectrometer detector. Using the obtained fraction, the retention time of isopropenylcresol was confirmed under the condition of composition analysis of the bisphenol C formation reaction liquid.

[ example 1]

(1) Preparation of the first mixture

In a separable flask equipped with a thermometer, a dropping funnel, a cannula and an anchor stirrer, 320g of toluene, 15g of methanol, 230g (2.13 moles) of o-cresol (reagent) manufactured by Fuji film and Wako pure chemical industries, Ltd., were charged under a nitrogen atmosphere to adjust the internal temperature to 10 ℃ or lower. Thereafter, 95g of 98 mass% sulfuric acid was slowly added thereto over 0.3 hour with stirring, followed by cooling to 5 ℃ or lower.

(2) Preparation of the 2 nd Mixed solution

In a 500mL Erlenmeyer flask, 50g of toluene, 65g (1.12 mol) of acetone, and 5.4g of dodecanethiol were mixed to prepare a2 nd mixed solution (dropwise addition).

(3) Preparation of reaction solution

After the internal temperature of the 1 st mixed solution was set to 5 ℃ or lower, the 2 nd mixed solution was supplied using the dropping funnel for 1 hour so that the internal temperature would not become 10 ℃ or higher, thereby preparing a reaction solution.

(4) Reaction of

The reaction solution thus prepared was stirred at an internal temperature of 10 ℃ for 2.5 hours.

(5) Refining (cleaning)

After the reaction, 190g of a 25% aqueous solution of sodium hydroxide was supplied, and the temperature was raised to 80 ℃. After reaching 80 ℃, standing is carried out, and the lower aqueous phase is extracted. To the obtained 1 st organic phase, 400g of deionized water was added, mixed for 30 minutes, and then allowed to stand to remove the aqueous phase. To the obtained 2 nd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. To the obtained 3 rd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was further added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. The resultant 4 th organic phase was extracted and the mass was measured to find that it was 666 g.

As a result of taking out a part of the 4 th organic phase and confirming the composition of the 4 th organic phase by high performance liquid chromatography, 5.3 mass% (5.3 mass% × mass of the organic phase 666g ÷ molecular weight of o-cresol 108 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 15.3 mol%) of o-cresol and 31.5 mass% (31.5 mass% × mass of the organic phase 666g × 2 ÷ molecular weight of bisphenol C256 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 78.0 mol%) of bisphenol C were produced.

(6) Refining (washing and devitrification)

To the obtained 4 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, and the lower aqueous phase (1 st aqueous phase) was removed to obtain a 5 th organic phase. The pH of the 1 st aqueous phase was 9.7. To the resulting 5 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (2 nd aqueous phase), to obtain a 6 th organic phase. To the obtained 6 th organic phase, 200g of deionized water was added, and after mixing for 30 minutes, the mixture was allowed to stand to remove the lower aqueous phase (3 rd aqueous phase). The conductivity of the 3 rd aqueous phase was 2.7. mu.S/cm.

The resultant 6 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Thereafter, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a crude and refined wet cake. The obtained wet cake was sprayed with 500g of toluene and washed, and solid-liquid separation was performed using a centrifugal separator to obtain a refined wet cake. The obtained purified wet cake was distilled off light boiling fractions at an oil bath temperature of 100 ℃ under reduced pressure using an evaporator equipped with an oil bath, whereby 190g of a white bisphenol C composition was obtained.

The methanol-dissolved color of the bisphenol C composition thus obtained was measured, and the Hazen color number was 0. The resulting bisphenol C composition was measured for color difference in melting, and found to have a Hazen color number of 3. The thermal hue stability of the bisphenol C composition obtained was measured, and the Hazen color number was 26. The thermal decomposition stability of the obtained bisphenol C composition was measured, and the amount of isopropenylcresol formed was 186 mass ppm.

The quality of the obtained bisphenol C composition was confirmed, and as a result, a characteristic peak was detected in high performance liquid chromatography at a retention time of 24.12 minutes. In order to identify the peak components, the peak components were measured by high performance liquid chromatography using a mass spectrometer, and it was confirmed that the peak components were trimethyl bisphenol a having a molecular weight of 270 g/mole and a structure represented by the following structural formula (IIa).

[ solution 13]

The resulting bisphenol C composition contained 210 mass ppm of trimethylbisphenol A.

The bisphenol C content of the obtained bisphenol C composition was 99.9 mass%.

The contents of sodium, iron, and aluminum in the obtained bisphenol C composition were measured, and were 0.04 mass ppm, 0.05 mass ppm, and 0.05 mass ppm, respectively.

[ example 2]

(1) Preparation of the first mixture

In a separable flask equipped with a thermometer, a dropping funnel, a cannula and an anchor stirrer, 320g of toluene, 15g of methanol, 5g (0.04 mol) of 2, 6-xylenol, 225g (2.08 mol) of Fuji film and o-cresol (reagent) manufactured by Wako pure chemical industries, Ltd., were charged under an air atmosphere, and the internal temperature was adjusted to 10 ℃ or lower. Thereafter, 95g of 98 mass% sulfuric acid was slowly added thereto over 0.3 hour with stirring, followed by cooling to 5 ℃ or lower.

(2) Preparation of the 2 nd Mixed solution

In a 500mL Erlenmeyer flask, 50g of toluene, 65g (1.12 mol) of acetone, and 5.4g of dodecanethiol were mixed to prepare a2 nd mixed solution (dropwise addition).

(3) Preparation of reaction solution

After the internal temperature of the 1 st mixed solution was set to 5 ℃ or lower, the 2 nd mixed solution was supplied using the dropping funnel for 1 hour so that the internal temperature would not become 10 ℃ or higher, thereby preparing a reaction solution.

(4) Reaction of

The reaction solution thus prepared was stirred at an internal temperature of 10 ℃ for 2.5 hours.

(5) Refining (cleaning)

After the reaction, 190g of a 25% aqueous solution of sodium hydroxide was supplied, and the temperature was raised to 80 ℃. After reaching 80 ℃, standing is carried out, and the lower aqueous phase is extracted. To the obtained 1 st organic phase, 400g of deionized water was added, mixed for 30 minutes, and then allowed to stand to remove the aqueous phase. To the obtained 2 nd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. To the obtained 3 rd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was further added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. The resultant 4 th organic phase was extracted and the mass was measured to find that it was 666 g.

As a result of taking out a part of the 4 th organic phase and confirming the composition of the 4 th organic phase by high performance liquid chromatography, 5.8 mass% (5.8 mass% × mass of the organic phase 666g ÷ molecular weight of o-cresol 108 g/mol ÷ mass of o-cresol charged 2.08 mol ═ 17.2 mol%) of o-cresol and 29.4 mass% (29.4 mass% × mass of the organic phase 666g × 2 ÷ molecular weight of bisphenol C256 g/mol ÷ mass of o-cresol charged 2.08 mol ═ 73.5 mol%) of bisphenol C were produced.

(6) Refining (washing and devitrification)

To the obtained 4 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, and the lower aqueous phase (1 st aqueous phase) was removed to obtain a 5 th organic phase. The pH of the 1 st aqueous phase was 9.7. To the resulting 5 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (2 nd aqueous phase), to obtain a 6 th organic phase. To the obtained 6 th organic phase, 200g of deionized water was added, and after mixing for 30 minutes, the mixture was allowed to stand to remove the lower aqueous phase (3 rd aqueous phase). The conductivity of the 3 rd aqueous phase was 2.7. mu.S/cm.

The resultant 6 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Thereafter, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a crude and refined wet cake. The obtained wet cake was sprayed with 500g of toluene and washed, and solid-liquid separation was performed using a centrifugal separator to obtain a refined wet cake. The obtained purified wet cake was distilled off of light boiling fractions at an oil bath temperature of 100 ℃ under reduced pressure using an evaporator equipped with an oil bath, whereby 178g of a white bisphenol C composition was obtained.

The bisphenol C content of the obtained bisphenol C composition was 99.7 mass%, and the content of trimethyl bisphenol a was 20000 mass ppm.

The methanol-dissolved color of the bisphenol C composition thus obtained was measured, and the Hazen color number was 0. The resulting bisphenol C composition was measured for color difference in melting, and found to have a Hazen color number of 8. The thermal hue stability of the bisphenol C composition obtained was measured, and the Hazen color number was 32. The thermal decomposition stability of the obtained bisphenol C composition was measured, and the amount of isopropenylcresol formed was 166 mass ppm.

The contents of sodium, iron, and aluminum in the obtained bisphenol C composition were measured, and were 0.02 mass ppm, 0.06 mass ppm, and 0.04 mass ppm, respectively.

Comparative example 1

(1) Preparation of the first mixture

320g of toluene, 15g of methanol, and 230g (2.13 moles) of o-cresol manufactured by LANXESS were charged into a separable flask equipped with a thermometer, a dropping funnel, a cannula, and an anchor stirring paddle under a nitrogen atmosphere so that the internal temperature was 10 ℃ or lower. Thereafter, 95g of 98 mass% sulfuric acid was slowly added thereto over 0.3 hour with stirring, followed by cooling to 5 ℃ or lower.

(2) Preparation of the 2 nd Mixed solution

In a 500mL Erlenmeyer flask, 50g of toluene, 65g (1.12 mol) of acetone, and 5.4g of dodecanethiol were mixed to prepare a2 nd mixed solution (dropwise addition).

(3) Preparation of reaction solution

After the internal temperature of the 1 st mixed solution was set to 5 ℃ or lower, the 2 nd mixed solution was supplied using the dropping funnel for 1 hour so that the internal temperature would not become 10 ℃ or higher, thereby preparing a reaction solution.

(4) Reaction of

The reaction solution thus prepared was stirred at an internal temperature of 10 ℃ for 2 hours.

(5) Refining (cleaning)

After the reaction, 190g of a 25% aqueous solution of sodium hydroxide was supplied, and the temperature was raised to 80 ℃. After reaching 80 ℃, standing is carried out, and the lower aqueous phase is extracted. To the obtained 1 st organic phase, 400g of deionized water was added, mixed for 30 minutes, and then allowed to stand to remove the aqueous phase. To the obtained 2 nd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. To the obtained 3 rd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was further added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. The resultant 4 th organic phase was extracted and the mass was measured to find that it was 666 g.

As a result of taking out a part of the 4 th organic phase and confirming the composition of the 4 th organic phase by high performance liquid chromatography, 5.3 mass% (5.3 mass% × mass of the organic phase 666g ÷ molecular weight of o-cresol 108 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 15.3 mol%) of o-cresol and 31.5 mass% (31.5 mass% × mass of the organic phase 666g × 2 ÷ molecular weight of bisphenol C256 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 78.0 mol%) of bisphenol C were produced.

(6) Refining (washing and devitrification)

The resulting 4 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Thereafter, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a crude and refined wet cake.

The total amount of the obtained crude refined wet cake and 420g of toluene were charged in a separable flask equipped with a thermometer, a dropping funnel, a cannula and an anchor-type stirring paddle under a nitrogen atmosphere, and the temperature was raised to 80 ℃ to obtain a homogeneous solution. To the resulting homogeneous solution was added 200g of deionized water, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (1 st aqueous phase) to obtain a 5 th organic phase. The pH of the 1 st aqueous phase was 9.2. To the resulting 5 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (2 nd aqueous phase), to obtain a 6 th organic phase. To the obtained 6 th organic phase, 200g of deionized water was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower aqueous phase (3 rd aqueous phase) was removed to obtain a 7 th organic phase. The conductivity of the 3 rd aqueous phase was 2.3. mu.S/cm.

The resulting 7 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Then, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a wet cake. The obtained wet cake was sprayed with 200g of toluene and washed, and solid-liquid separation was performed using a centrifugal separator to obtain a refined wet cake. The obtained purified wet cake was distilled off of light boiling fractions at an oil bath temperature of 100 ℃ under reduced pressure using an evaporator equipped with an oil bath, whereby 183g of a white bisphenol C composition was obtained.

The bisphenol C content of the obtained bisphenol C composition was 99.9 mass%, and trimethyl bisphenol a was not detected (the limit of quantitation was less than 0.1 mass ppm).

The methanol-soluble color of the bisphenol C composition thus obtained was measured, and the Hazen color number was 3. The resulting bisphenol C composition was measured for color difference in melting, and found to have a Hazen color number of 48. The resulting bisphenol C composition was measured for thermal hue stability and found to have a Hazen color number of 120. The thermal decomposition stability of the obtained bisphenol C was measured, and the amount of isopropenylcresol formed was 485 mass ppm.

The contents of sodium, iron, and aluminum in the obtained bisphenol C composition were measured, and were 0.22 mass ppm, 0.89 mass ppm, and 0.12 mass ppm, respectively.

Comparative example 2

The content of trimethyl bisphenol A in bisphenol C reagent manufactured by Fuji film and Wako pure chemical industries, Ltd is 185 ppm by mass.

The reagent bisphenol C was measured for its methanol-soluble color, and the Hazen color number was 20. Further, the reagent bisphenol C had a Hazen color value of 46 as a result of measurement of the color difference in melting. Further, the reagent bisphenol C was measured for its thermal hue stability, and its Hazen color number was 114. Further, the thermal decomposition stability of this reagent bisphenol C was measured, and the amount of isopropenylcresol formed was 585 mass ppm.

The contents of sodium, iron and aluminum in the obtained bisphenol C composition were measured, and as a result, they were 0.81 mass ppm, 1.22 mass ppm and 0.23 mass ppm, respectively.

Comparative example 3

(1) Preparation of the first mixture

320g of toluene, 15g of methanol, and 230g (2.13 moles) of o-cresol manufactured by JFE chemical company were charged in a separable flask equipped with a thermometer, a dropping funnel, a cannula, and an anchor stirrer under a nitrogen atmosphere so that the internal temperature was 10 ℃ or lower. Thereafter, 95g of 98 mass% sulfuric acid was slowly added thereto over 0.3 hour with stirring, followed by cooling to 5 ℃ or lower.

(2) Preparation of the 2 nd Mixed solution

In a 500mL Erlenmeyer flask, 50g of toluene, 65g (1.12 mol) of acetone, and 5.4g of dodecanethiol were mixed to prepare a2 nd mixed solution (dropwise addition).

(3) Preparation of reaction solution

After the internal temperature of the 1 st mixed solution was set to 5 ℃ or lower, the 2 nd mixed solution was supplied using the dropping funnel for 1 hour so that the internal temperature would not become 10 ℃ or higher, thereby preparing a reaction solution.

(4) Reaction of

The reaction solution thus prepared was stirred at an internal temperature of 10 ℃ for 2 hours.

(5) Refining (cleaning)

After the reaction, 190g of a 25% aqueous solution of sodium hydroxide was supplied, and the temperature was raised to 80 ℃. After reaching 80 ℃, standing is carried out, and the lower aqueous phase is extracted. To the obtained 1 st organic phase, 400g of deionized water was added, mixed for 30 minutes, and then allowed to stand to remove the aqueous phase. To the obtained 2 nd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. To the obtained 3 rd organic phase, 120g of a 1.5 mass% sodium hydrogencarbonate solution was further added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower layer was extracted. The resultant 4 th organic phase was extracted and the mass was measured to find that it was 666 g.

As a result of taking out a part of the 4 th organic phase and confirming the composition of the 4 th organic phase by high performance liquid chromatography, 6.3 mass% (6.3 mass% × mass of the organic phase 666g ÷ molecular weight of o-cresol 108 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 18.5 mol%) of o-cresol and 28.4 mass% (28.4 mass% × mass of the organic phase 666g × 2 ÷ molecular weight of bisphenol C256 g/mol ÷ mass of o-cresol charged 2.1 mol ═ 70.4 mol%) of bisphenol C were produced.

(6) Refining (washing and devitrification)

The resulting 4 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Thereafter, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a crude and refined wet cake.

The total amount of the obtained crude refined wet cake and 420g of toluene were charged in a separable flask equipped with a thermometer, a dropping funnel, a cannula and an anchor-type stirring paddle under a nitrogen atmosphere, and the temperature was raised to 80 ℃ to obtain a homogeneous solution. To the resulting homogeneous solution was added 200g of deionized water, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (1 st aqueous phase) to obtain a 5 th organic phase. The pH of the 1 st aqueous phase was 9.3. To the resulting 5 th organic phase, 200g of deionized water was added, mixed for 30 minutes, and then allowed to stand, to remove the lower aqueous phase (2 nd aqueous phase), to obtain a 6 th organic phase. To the obtained 6 th organic phase, 200g of deionized water was added, and after mixing for 30 minutes, the mixture was allowed to stand, and the lower aqueous phase (3 rd aqueous phase) was removed to obtain a 7 th organic phase. The conductivity of the 3 rd aqueous phase was 2.1. mu.S/cm.

The resulting 7 th organic phase was cooled from 80 ℃ to 20 ℃ and maintained at 20 ℃ to precipitate bisphenol C. Then, the mixture was cooled to 10 ℃ and brought to 10 ℃, and then solid-liquid separation was carried out using a centrifugal separator to obtain a wet cake. The obtained wet cake was sprayed with 200g of toluene and washed, and solid-liquid separation was performed using a centrifugal separator to obtain a refined wet cake. The obtained purified wet cake was distilled off light boiling fractions at an oil bath temperature of 100 ℃ under reduced pressure using an evaporator equipped with an oil bath, whereby 160g of a white bisphenol C composition was obtained.

The bisphenol C content of the obtained bisphenol C composition was 99.9 mass%, and the trimethyl bisphenol a content was 55 mass ppm.

The methanol-soluble color of the bisphenol C composition thus obtained was measured, and the Hazen color number was 2. The resulting bisphenol C composition was measured for color difference in melting, and found to have a Hazen color number of 39. The thermal hue stability of the bisphenol C composition obtained was measured, and the Hazen color number was 105. The thermal decomposition stability of the obtained bisphenol C was measured, and the amount of isopropenylcresol formed was 412 mass ppm.

The contents of sodium, iron, and aluminum in the obtained bisphenol C composition were measured, and were 0.07 mass ppm, 0.09 mass ppm, and 0.08 mass ppm, respectively.

In examples 1 and 2 and comparative examples 1 to 3, the content of trimethyl bisphenol a (bisphenol (II)) in the bisphenol C composition, the methanol dissolution color, the color difference of melting, the thermal hue stability, the thermal decomposition stability, and the contents of metals (sodium (Na), iron (Fe), and aluminum (Al)) are shown in table 1.

As is clear from Table 1, by containing 150 to 20000 ppm by mass of trimethylbisphenol A, the methanol-soluble color, the color difference of melt, and the thermal hue stability can be improved. It is also found that the thermal decomposition stability can be improved by containing 150 to 20000 mass ppm of trimethylbisphenol A.

[ Table 1]

[ example 3]

100.00g (0.39 mol) of the bisphenol C composition obtained in example 1, 86.49g (0.4 mol) of diphenyl carbonate, and 479. mu.L of a 400 ppm by mass aqueous cesium carbonate solution were charged into a glass reaction vessel having an internal capacity of 150mL and equipped with a stirrer and a condenser. The glass reaction vessel was depressurized to about 100Pa, and then, the pressure was returned to atmospheric pressure with nitrogen gas, and the operation was repeated 3 times to replace the interior of the reaction vessel with nitrogen. Thereafter, the reaction vessel was immersed in an oil bath at 200 ℃ to dissolve the contents.

The pressure in the reaction vessel was reduced from an absolute pressure of 101.3kPa to 13.3kPa over 40 minutes while distilling off phenol by-produced by the oligomerization reaction of bisphenol C and diphenyl carbonate in the reaction vessel at a rotation speed of the stirrer of 100 times per minute. Then, the pressure in the reaction vessel was maintained at 13.3kPa, and the transesterification reaction was carried out for 80 minutes while further removing phenol by distillation. Thereafter, the temperature outside the reaction vessel was raised to 250 ℃ and the pressure in the reaction vessel was reduced from 13.3kPa absolute to 399Pa over 40 minutes, and the distilled phenol was discharged out of the system.

Thereafter, the temperature outside the reaction vessel was raised to 280 ℃ and the absolute pressure in the reaction vessel was reduced to 30Pa to conduct polycondensation reaction. When the stirrer in the reaction tank reaches a predetermined stirring power, the polycondensation reaction is terminated. The time (latter polymerization time) from the completion of the polymerization after the temperature had risen to 280 ℃ was 210 minutes.

Then, the reaction vessel was repressed to an absolute pressure of 101.3kPa using nitrogen, and then, the pressure was increased to a gage pressure of 0.2MPa, and the polycarbonate resin was taken out from the bottom of the reaction vessel in a strand form, to obtain a strand-form polycarbonate resin.

Thereafter, the strands were pelletized using a rotary cutter to obtain a polycarbonate resin in pellet form.

The obtained polycarbonate resin had a viscosity average molecular weight (Mv) of 24800 and a pellet YI of 6.9.

The alkali hydrolyzate of the obtained polycarbonate resin contained 160 ppm by mass of trimethylbisphenol A relative to the polycarbonate resin.

[ example 4]

The procedure of example 3 was repeated except for using 100.00g (0.39 mol) of the bisphenol C composition obtained in example 2 in place of 100.00g (0.39 mol) of the bisphenol C composition obtained in example 1 in example 3.

The time (latter polymerization time) from the completion of the polymerization after the temperature had risen to 280 ℃ was 220 minutes.

The obtained polycarbonate resin had a viscosity average molecular weight (Mv) of 24800 and a pellet YI of 6.5.

The alkali hydrolyzate of the obtained polycarbonate resin contained 16200 mass ppm of trimethylbisphenol A relative to the polycarbonate resin.

Comparative example 3

The procedure of example 3 was repeated except for using 100.00g (0.39 mol of bisphenol C) of the bisphenol C composition obtained in comparative example 1 in place of 100.00g (0.39 mol of bisphenol C) of the bisphenol C composition obtained in example 1 in example 3.

The time (latter polymerization time) from the completion of the polymerization after the temperature had risen to 280 ℃ was 230 minutes.

The obtained polycarbonate resin had a viscosity average molecular weight (Mv) of 24800 and a pellet YI of 10.2.

The alkali hydrolyzate of the obtained polycarbonate resin contained 2 mass ppm of trimethylbisphenol A relative to the polycarbonate resin.

In examples 3 and 4 and comparative example 3, the ratio of the content of trimethylbisphenol a in the alkali hydrolyzate of polycarbonate resin to the polycarbonate resin and the pellet YI of the obtained polycarbonate resin are shown in table 2.

As is clear from Table 2, by adding a trimethylbisphenol A component to the polycarbonate resin, the pellet YI was improved.

[ Table 2]

While the present invention has been described in detail and with reference to specific embodiments thereof, it will be apparent to one skilled in the art that various changes can be made therein without departing from the spirit and scope thereof.

The present application is based on japanese patent application 2019-.