JPWO2020171039A1 - New fluorene compound - Google Patents

Abstract

The challenge is to provide a novel fluorene compound having a 2,3-benzofluorene skeleton that is highly versatile as a "dicarboxylic acid component" for resin raw materials, has a high refractive index, and also has excellent solubility in organic solvents. And. The above problem can be solved by the fluorene compound represented by the following general formula (1). [Chemical 1]

Description

The present invention relates to novel fluorene compounds. More specifically, the present invention relates to a novel fluorene compound having a 2,3-benzofluorene skeleton.

で表される９，９−ビス（４−ヒドロキシフェニル）−２，３−ベンゾフルオレンから製造される樹脂は、光学特性に優れるとして着目されている（例えば、特許文献１等）。
この９，９−ビス（４−ヒドロキシフェニル）−２，３−ベンゾフルオレンや、これに近年汎用されているヒドロキシエトキシ基を導入した化合物、例えば、９，９−ビス｛４−（２−ヒドロキシエトキシ）フェニル｝−２，３−ベンゾフルオレンは、「ジオール成分」として、ポリカーボネート樹脂原料の他、ポリエステル樹脂やポリアリーレート樹脂などの樹脂原料として利用または注目されている。
これら化合物の例のように、樹脂原料として「ジオール成分」の開発は盛んに行われ、望む樹脂性能に応じた「ジオール成分」の提案は多くなされている。
一方、ポリエステル樹脂やポリアリーレート樹脂などの樹脂原料として、「ジオール成分」と「ジカルボン酸成分」の２成分が必要であるにも関わらず、「ジカルボン酸成分」の開発は遅れており、選択できる「ジカルボン酸成分」の種類は少ないという問題があった。Conventionally, a compound group having a fluorene skeleton such as 9,9-bis (4-hydroxyphenyl) fluorene exhibits excellent functions in heat resistance, optical properties, etc., and therefore, a thermoplastic synthetic resin raw material such as a polycarbonate resin, It is used in applications such as thermosetting resin raw materials such as epoxy resins, antioxidant raw materials, heat-sensitive recorder raw materials, and photosensitive resist raw materials. Above all, the following chemical formula

The resin produced from 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene represented by (1) has been attracting attention as having excellent optical properties (for example, Patent Document 1 and the like).
This 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene and a compound into which a hydroxyethoxy group, which has been widely used in recent years, is introduced, for example, 9,9-bis {4- (2-hydroxy) Ethoxy) phenyl} -2,3-benzofluorene has been used or attracted attention as a "diol component" as a raw material for polycarbonate resins as well as raw materials for resins such as polyester resins and polyarylate resins.
As in the case of these compounds, "diol components" have been actively developed as resin raw materials, and many proposals have been made for "diol components" according to desired resin performance.
On the other hand, although the two components of "diol component" and "dicarboxylic acid component" are required as resin raw materials such as polyester resin and polyarylate resin, the development of "dicarboxylic acid component" has been delayed and selected. There was a problem that the types of "dicarboxylic acid components" that could be produced were small.

Japanese Unexamined Patent Publication No. 2017-036249

The present invention has been made in the background of the above-mentioned circumstances, and has high versatility as a "dicarboxylic acid component" of a resin raw material, has a high refractive index, and has excellent solubility in an organic solvent. An object of the present invention is to provide a novel fluorene compound having a 2,3-benzofluorene skeleton.

As a result of diligent studies to solve the above-mentioned problems, the present inventor has found a fluorene compound having a 2,3-benzofluorene skeleton such as 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene. It has been found that it is a novel compound and has high versatility as a "dicarboxylic acid component" of a resin raw material due to its chemical structure, has a high refractive index, and has excellent solubility in an organic solvent. , The present invention has been completed.

（式中、Ｒ_１およびＲ_２は、各々独立して水素原子、炭素原子数１〜６のアルキル基、アルカリ金属原子、アルカリ土類金属原子、Ｒ_３およびＲ_４は、各々独立して炭素原子数１〜６のアルキル基、フェニル基、Ｒ_５およびＲ_６は、各々独立して水素原子、ハロゲン原子、炭素原子数１〜６のアルキル基、炭素原子数２〜６のアルケニル基、炭素原子数１〜６のアルコキシ基、炭素原子数６〜１２のアリール基を示し、ａ、ｂおよびｃは各々独立して０〜４の整数、ｄは０〜６の整数を示す。）The present invention is as follows.
1. 1. A fluorene compound represented by the following general formula (1).

(In the formula, R ₁ and R ₂ are independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, alkali metal atoms, alkaline earth metal atoms, and R ₃ and R ₄ are independent carbon atoms, respectively. alkyl group of 1 -C 6, phenyl group, _{R 5} and _{R 6} are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a carbon It represents an alkoxy group having 1 to 6 atoms and an aryl group having 6 to 12 carbon atoms, where a, b and c independently represent an integer of 0 to 4, and d represents an integer of 0 to 6).

According to the present invention, as represented by the above general formula (1), a new resin raw material is provided as a novel "dicarboxylic acid component" having a chemical structure having two carboxylic acids / carboxylic acid esters at the ends. be able to.
As will be described later, since the compound of the present invention is a compound having a high refractive index, a resin having a high refractive index can be obtained by using it as a "dicarboxylic acid component" as a resin raw material, and a resin having excellent optical properties. It can be expected as a raw material.
In particular, the "dicarboxylic acid component" that can be used as a resin raw material for optical applications has few types, and the novel fluorene compound of the present invention is industrialized due to its optical properties, heat resistance, solvent solubility and other performances. It is considered to be a novel compound that is very useful in applications.

It is a figure which shows the differential scanning calorimetry (DSC) curve of the crystal obtained in Example 1. FIG. It is a figure which shows the differential scanning calorimetry (DSC) curve of the crystal obtained in Example 3. FIG. It is a figure which shows the differential thermal / thermogravimetric analysis (DTG) curve of the crystal obtained in Example 3. FIG. It is a figure which shows the differential scanning calorimetry (DSC) curve of the crystal obtained in Example 4. FIG. It is a figure which shows the differential thermal / thermogravimetric analysis (DTG) curve of the crystal obtained in Example 7. It is a figure which shows the differential thermal / thermogravimetric analysis (DTG) curve of the crystal obtained in Example 8. It is a figure which shows the differential thermal / thermogravimetric analysis (DTG) curve of the crystal obtained in Example 9. FIG. It is a figure which shows the differential thermal / thermogravimetric analysis (DTG) curve of the crystal obtained in Example 10.

（式中、Ｒ_１およびＲ_２は、各々独立して水素原子、炭素原子数１〜６のアルキル基、アルカリ金属原子、アルカリ土類金属原子、Ｒ_３およびＲ_４は、各々独立して炭素原子数１〜６のアルキル基、フェニル基、Ｒ_５およびＲ_６は、各々独立して水素原子、ハロゲン原子、炭素原子数１〜６のアルキル基、炭素原子数２〜６のアルケニル基、炭素原子数１〜６のアルコキシ基、炭素原子数６〜１２のアリール基を示し、ａ、ｂおよびｃは各々独立して０〜４の整数、ｄは０〜６の整数を示す。）Hereinafter, the present invention will be described in detail.
The novel fluorene of the present invention is a compound represented by the following general formula (1).

(In the formula, R ₁ and R ₂ are independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, alkali metal atoms, alkaline earth metal atoms, and R ₃ and R ₄ are independent carbon atoms, respectively. alkyl group of 1 -C 6, phenyl group, _{R 5} and _{R 6} are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a carbon It represents an alkoxy group having 1 to 6 atoms and an aryl group having 6 to 12 carbon atoms, where a, b and c independently represent an integer of 0 to 4, and d represents an integer of 0 to 6).

In the general formula (1), when _{any one or more of R 1 to} R ₆ is an alkyl group having 1 to 6 carbon atoms, a preferable alkyl group is a linear or branched chain having 1 carbon atom. ~ 4 Alkyl groups, specific examples thereof include methyl group, ethyl group, n-propyl group, i-propyl group, n-butyl group, iso-butyl group, sec-butyl group and tert-butyl group. Be done.
When _{one or both of R 5} and R ₆ are alkenyl groups having 2 to 6 carbon atoms, the preferred alkenyl group is a linear or branched alkenyl group having 2 to 4 carbon atoms. Specific examples thereof include a vinyl group, a 1-methylethenyl group, a propenyl group, a butenyl group, an isobutenyl group, a pentenyl group and a hexenyl group.
If one or both of R _5, R ₆ is an alkoxy group having 1 to 6 carbon atoms, examples of preferred alkoxy groups are straight-chain or branched alkoxy group having 1 to 4 carbon atoms, Specific examples thereof include a methoxy group, an ethoxy group, an n-propoxy group, an i-propoxy group, an n-butoxy group, an i-butoxy group and a t-butoxy group.
If one or both of R _{5, R 6} is an aryl group having 6 to 12 carbon atoms, a phenyl group, a naphthyl group.

In the general formula (1), R ₁ and R ₂ are preferably independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, and alkali metal atoms, respectively, and independently have hydrogen atoms and carbon atoms 1 to 4 respectively. Alkyl group, lithium atom, potassium atom and sodium atom are more preferable, and hydrogen atom, methyl group and ethyl group are more preferable independently. Above all, it is particularly preferable that both _{R 1} and R _{2 are hydrogen atoms.}
In the general formula (1), R ₃ and R ₄ are preferably an alkyl group and a phenyl group having 1 to 4 carbon atoms independently, and more preferably a methyl group and a phenyl group, respectively. 0, 1, 2, and 3 are preferable for a and b independently, 0 and 1 are more preferable for each independently, and it is particularly preferable that both a and b are 0. Further, _{the substitution positions of R 3} and R ₄ are preferably 2-position, 3-position or 5-position, and more preferably 3-position or / and 5-position.
In the general formula (1), R ₅ and R ₆ are independently halogen atoms, an alkyl group having 1 to 4 carbon atoms, an alkenyl group having 2 to 4 carbon atoms, and an alkoxy group having 1 to 4 carbon atoms, respectively. , Phenyl group and naphthyl group are preferable. It is preferable that c and d are 0 and 1 independently, and it is more preferable that both c and d are 0.

その他の好ましい化合物としては、
９，９−ビス［（４−カルボキシメトキシ−３−メチル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
９，９−ビス［（４−カルボキシメトキシ−２−メチル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
９，９−ビス［（４−カルボキシメトキシ−３、５−ジメチル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
９，９−ビス［（４−カルボキシメトキシ−２，５−ジメチル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
９，９−ビス［（４−カルボキシメトキシ−３−フェニル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
９，９−ビス［（４−カルボキシメトキシ−２−フェニル）フェニル］−２，３−ベンゾフルオレンや、そのカリウム塩、ナトリウム塩、メチルエステル、エチルエステル
が挙げられる。As a preferable example of the fluorene compound represented by the above general formula (1), 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene represented by the following chemical formula, a potassium salt thereof, and a sodium salt thereof are used. , Methyl ester, ethyl ester and the like.

Other preferred compounds include
9,9-bis [(4-carboxymethoxy-3-methyl) phenyl] -2,3-benzofluorene and its potassium salt, sodium salt, methyl ester, ethyl ester 9,9-bis [(4-carboxymethoxy) -2-Methyl) phenyl] -2,3-benzofluorene and its potassium salt, sodium salt, methyl ester, ethyl ester 9,9-bis [(4-carboxymethoxy-3,5-dimethyl) phenyl] -2 , 3-Benzofluorene and its potassium salt, sodium salt, methyl ester, ethyl ester 9,9-bis [(4-carboxymethoxy-2,5-dimethyl) phenyl] -2,3-benzofluorene and its potassium Salts, sodium salts, methyl esters, ethyl esters 9,9-bis [(4-carboxymethoxy-3-phenyl) phenyl] -2,3-benzofluorene and its potassium salts, sodium salts, methyl esters, ethyl esters 9 , 9-Bis [(4-carboxymethoxy-2-phenyl) phenyl] -2,3-benzofluorene, its potassium salt, sodium salt, methyl ester, ethyl ester and the like.

９，９−ビス（４−ヒドロキシフェニル）−２，３−ベンゾフルオレン類は、公知の９，９−ビス（４−ヒドロキシフェニル）フルオレン等のフルオレン骨格を有する化合物の製造方法を適用できるが、例えば、９，９−ビス（４−ヒドロキシフェニル）−２，３−ベンゾフルオレンは、下記反応式に示すように、フェノールと２，３−ベンゾ−９−フルオレノンとを原料とし、これらを酸触媒の存在下に反応させる縮合反応により得ることができる。
＜縮合反応の反応式＞

<About the synthesis method>
The method for synthesizing the fluorene compound represented by the above general formula (1) of the present invention is not particularly limited, and is, for example, halogenated with 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorenes. It is obtained by an etherification reaction in which an alkyl acetate or the like is reacted under alkaline conditions.
The reaction formula of the etherification reaction for obtaining 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene, which is the compound of the present invention, is shown below.
<Reaction formula of etherification reaction>

As the 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorenes, a known method for producing a compound having a fluorene skeleton such as 9,9-bis (4-hydroxyphenyl) fluorene can be applied. For example, 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene uses phenol and 2,3-benzo-9-fluorenone as raw materials as shown in the reaction formula below, and these are acid catalysts. It can be obtained by a condensation reaction that reacts in the presence of fluorene.
<Reaction formula of condensation reaction>

<About one example of raw material synthesis-condensation reaction->
First, as an example of raw material synthesis of the compound of the present invention, synthesis of 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene by a condensation reaction between phenol and 2,3-benzo-9-fluorenone. The method will be described.
The molar ratio of phenol charged to 2,3-benzo-9-fluorenone is not particularly limited as long as it is the theoretical value (2.0) or more, but is usually in the range of 2 to 20 times the molar amount, preferably. It is used in the range of 3 to 10 times the molar amount.
The acid catalyst used is not particularly limited, and a known acid catalyst can be used. Specific acid catalysts include, for example, hydrochloric acid, hydrogen chloride gas, 60-98% sulfuric acid, 85% phosphoric acid and other inorganic acids, p-toluenesulfonic acid, methanesulfonic acid, oxalic acid, formic acid, trichloroacetic acid or tri. Examples thereof include organic acids such as fluoroacetic acid and solid acids such as heteropolyacids. Hydrogen chloride gas is preferable. The appropriate amount of such an acid catalyst to be used varies depending on the reaction conditions. For example, in the case of hydrogen chloride gas, the air of the reaction system is replaced with an inert gas such as nitrogen gas, and then hydrogen chloride gas is blown into the reaction system. It is preferable that the concentration of hydrogen chloride gas in the gas phase in the reaction vessel is 75 to 100% by volume, and the concentration of hydrogen chloride in the reaction solution is saturated. In the case of 35% hydrochloric acid, it is used in the range of 5 to 70 parts by weight, preferably in the range of 10 to 40 parts by weight, and more preferably in the range of 20 to 30 parts by weight with respect to 100 parts by weight of phenol.
In the reaction, a co-catalyst may be used together with the acid catalyst, if necessary. For example, when hydrogen chloride gas is used as a catalyst, the reaction rate can be accelerated by using thiols as a co-catalyst. Examples of such thiols include alkyl mercaptans and mercaptocarboxylic acids, preferably alkyl mercaptans having 1 to 12 carbon atoms and mercaptocarboxylic acids having 1 to 12 carbon atoms, for example, methyl mercaptan and ethyl. Examples thereof include alkali metal salts such as mercaptan, n-octyl mercaptan, n-dodecyl mercaptan and their sodium salts, thioacetic acid, β-mercaptopropionic acid and the like. In addition, these can be used alone or in combination of two or more types. The amount of thiols used as a co-catalyst is usually in the range of 1 to 30 mol%, preferably in the range of 2 to 10 mol% with respect to the raw material 2,3-benzo-9-fluorenone.

The reaction solvent may not be used in the reaction, but it may be used for reasons such as improvement in operability and reaction rate during industrial production. The reaction solvent is not particularly limited as long as it does not distill off from the reaction vessel at the reaction temperature and is inactive in the reaction. For example, aromatic hydrocarbons such as toluene and xylene, methanol, ethanol, 1-propanol and 2- Examples thereof include lower aliphatic alcohols such as propanol, organic solvents such as saturated aliphatic hydrocarbons such as hexane, heptane, and cyclohexane, water, or mixtures thereof. Of these, aromatic hydrocarbons are preferably used.
The reaction temperature varies depending on the type of the raw material phenol or the acid catalyst, but when hydrogen chloride gas is used as the acid catalyst, it is usually in the range of 10 to 60 ° C, preferably 25 to 50 ° C. The reaction pressure is usually carried out under normal pressure, but depending on the boiling point of the organic solvent that may be used, the reaction pressure may be carried out under pressure or reduced pressure so that the reaction temperature is within the above range.
The reaction time varies depending on the type of phenol and acid catalyst as a raw material and reaction conditions such as reaction temperature, but is usually completed in about 1 to 30 hours.
The end point of the reaction can be confirmed by liquid chromatography or gas chromatography analysis. It is preferable that the end point of the reaction is the time when the unreacted 2,3-benzo-9-fluorenone disappears and the increase of the target substance is no longer observed.

<Post-treatment of raw material synthesis reaction>
After completion of the reaction, known post-treatment methods can be applied. For example, in order to neutralize the acid catalyst, an alkaline aqueous solution such as a sodium hydroxide aqueous solution or an ammonia aqueous solution is added to the reaction termination liquid to neutralize the acid catalyst. The neutralized reaction mixture is allowed to stand, and if necessary, a solvent that separates from water is added to separate and remove the aqueous layer. If necessary, distilled water is added to the obtained oil layer, stirred and washed with water, and then the operation of separating and removing the water layer is repeated once or multiple times to remove the neutralized salt, and excess oil is removed from the obtained oil layer. The phenol is removed by vacuum distillation. A solvent such as an aromatic hydrocarbon that separates from water is added to the obtained residue to form a uniform solution, which is cooled to separate the precipitated crystals to obtain crude crystals.

<Examples of synthesis of the compound of the present invention-etherification reaction->
Next, as an example of synthesis of the compound of the present invention, 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene was added to 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene. The resulting etherification reaction will be described.
Examples of the alkyl halides to be reacted with 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene include methyl chloroacetate, ethyl chloroacetate, n-propyl chloroacetate, isopropyl chloroacetate, and chloroacetic acid. n-butyl, isobutyl chloroacetate, tertiary butyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, n-propyl bromoacetate, isopropyl bromoacetate, n-butyl bromoacetate, isobutyl bromoacetate, tertiary butyl bromoacetate and the like. Be done. Of these, methyl chloroacetate or ethyl chloroacetate is preferable.
The molar ratio of alkyl halide acetate to 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene is not particularly limited as long as it is the theoretical value (2.0) or more. It is usually used in the range of 2 to 20 times the molar amount, preferably in the range of 2 to 10 times the molar amount, and more preferably in the range of 2 to 6 times the molar amount.
The reaction is carried out in the presence of a base, and examples of the base used include triethylamine, pyridine, sodium hydroxide, potassium hydroxide, sodium carbonate, potassium carbonate, sodium hydrogencarbonate, potassium hydrogencarbonate and the like. Of these, sodium carbonate and potassium carbonate are preferable. The molar ratio of the base charged is usually in the range of 0.8 to 4 times the molar amount, preferably in the range of 0.85 to 3 times the molar amount, and more preferably 0.9 to 2 times the molar amount with respect to the alkyl halide. It is a range of quantities.
Further, a catalyst may be used, for example, an alkali metal bromide salt such as sodium bromide or potassium bromide, an alkali metal iodide salt such as sodium iodide or potassium iodide, ammonium bromide, ammonium iodide or the like. Can be mentioned. The amount of the catalyst used is usually in the range of 0.1 to 100% by weight, preferably in the range of 0.1 to 20% by weight, based on 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene. , More preferably in the range of 0.1 to 10% by weight.

Although it is not necessary to use a reaction solvent in the reaction, it is preferable to use it for reasons such as improvement in operability and reaction rate during industrial production. The reaction solvent is not particularly limited as long as it does not distill off from the reaction vessel at the reaction temperature and is inactive in the reaction. For example, ketones such as acetone, methyl ethyl ketone, methyl isobutyl ketone and cyclohexanone, tetrahydrofuran, 1,4- Examples thereof include ethers such as dioxane, 1,3-dioxane and diethoxyethane, and aprotonic polar solvents such as acetonitrile, dimethyl sulfoxide, dimethylformamide and N-methylpyrrolidone. Each of these organic solvents may be used alone, or two or more kinds may be used in combination as appropriate for adjusting the polarity. Of these, methyl isobutyl ketone and acetonitrile are preferable.
The reaction temperature is usually in the range of 25 to 120 ° C, preferably in the range of 40 to 110 ° C, more preferably in the range of 50 to 100 ° C. If the reaction temperature is high, the yield will decrease due to hydrolysis of the produced ester compound, and if the reaction temperature is low, the reaction rate will slow down, which is not preferable. The reaction pressure is usually carried out under normal pressure, but depending on the boiling point of the organic solvent used, the reaction pressure may be carried out under pressure or reduced pressure so that the reaction temperature is within the above range.
The end point of the reaction can be confirmed by liquid chromatography or gas chromatography analysis. It is preferable that the end point of the reaction is the time when the unreacted 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene disappears and the increase of the target substance is no longer observed. The reaction time varies depending on the reaction conditions such as the reaction temperature, but is usually completed in about 1 to 30 hours.

When the target product is an ester compound such as 9,9-bis (4-methoxycarbonylmethoxyphenyl) -2,3-benzofluorene, the target ester compound is purified from the reaction product mixture after the etherification reaction is completed. It is preferable to isolate the ester, for example, it can be obtained by performing post-treatment operations such as neutralization, washing with water, crystallization, filtration, distillation, and separation by column chromatography after completion of the reaction according to a conventional method. In order to further increase the purity, purification by distillation, recrystallization or column chromatography may be carried out according to a conventional method.
When the target compound is a carboxylate such as 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene, post-reaction treatment such as neutralization and washing with water is performed after the etherification reaction is completed. The obtained ester compound can be obtained as a crude product by alkaline hydrolysis according to a conventional method without purifying the obtained ester compound. Here, the alkaline compound used for alkaline hydrolysis is not particularly limited, but for example, alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferable, and the concentration is usually 12 to 60% by weight. Used as an aqueous solution of. In addition, such an alkaline compound is usually 2 mol or more, preferably 2. It is used in the range of 1-10 mol. Normally, water is used as a reaction solvent in the hydrolysis reaction, but if necessary, an organic solvent such as an alcohol or a ketone that is mixed with water at an arbitrary ratio, or a mixture of such an organic solvent and water is used. Solvents are also used. It is also possible to continue to use the reaction solvent such as methyl isobutyl ketone and acetonitrile used in the etherification reaction. The reaction temperature of hydrolysis is usually 30 to 100 ° C., preferably 50 to 90 ° C., and under such reaction conditions, it is usually completed in about 3 to 5 hours. By this hydrolysis reaction, an alkali metal salt of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene can be obtained.

When the target product is a carboxylic acid such as 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene, the above hydrolysis reaction product is treated with concentrated hydrochloric acid or the like and then mixed with water. Immiscible organic solvents such as aromatic hydrocarbons such as toluene, xylene and benzene, aliphatic hydrocarbons having 5 or more carbon atoms such as hexane, heptane and cyclohexane, and methylisobutyl ketones having 5 or more carbon atoms. It is preferable to purify and isolate after washing with an aliphatic ketone or the like. In order to further increase the purity, purification by distillation, recrystallization or column chromatography may be carried out according to a conventional method.

The novel fluorene compound of the present invention has excellent properties such as high refractive index, high heat resistance, and high solubility in a wide range of organic solvents, and is suitable as a raw material (monomer) for a resin, a reaction component of a derivative, and the like. Can be used. Therefore, the novel fluorene compound of the present invention or a derivative thereof, or a resin using the novel fluorene compound as a resin raw material (monomer) is, for example, a film (for example, an optical film, a liquid crystal film, an organic EL (electroluminescence) film, EMI). Shielding films, etc.), lenses (eg, pickup lenses, etc.), protective films (eg, protective films for electronic devices, liquid crystal members, etc.), electro / electronic materials (carrier transport agents, light emitters, organic photoconductors, organic photosensitizers, etc.) Body, heat-sensitive recording material, hologram recording material, photochromic material, etc.), electrical / electronic parts or equipment (for example, optical disk, inkjet printer, digital paper, organic semiconductor laser, dye-sensitized solar cell, EMI shield film, organic EL element , Color filters, etc.), mechanical parts or equipment (automobiles, aeronautical / space materials, sensors, sliding members, etc.) and the like. In particular, the resin used as the novel fluorene compound of the present invention has excellent optical properties and is therefore useful for forming a molded product for optical use. Examples of such an optical molded body include an optical film. Optical films include polarizing films (and the polarizing elements and polarizing plate protective films that compose them), retardation films, alignment films (alignment films), viewing angle expansion (compensation) films, diffuser plates (films), light guide plates, and the like. Brightness improving film, near infrared absorbing film, reflective film, antireflection (AR) film, antireflection (LR) film, antiglare (AG) film, transparent conductive (ITO) film, idiosyncratic conductive film (ACF), electromagnetic wave Examples thereof include a shielding (EMI) film, a film for an electrode substrate, a barrier film, a color filter layer, a black matrix layer, an adhesive layer between optical films, or a release layer. In particular, the film is useful as an optical film used for a display of an apparatus. Specific examples of the display member (or display) provided with such an optical film include FPD devices such as personal computer monitors, televisions, mobile phones, car navigation systems, and touch panels (for example, LCDs, etc.). PDP, etc.) and the like.

Hereinafter, the present invention will be specifically described with reference to Examples, but the present invention is not limited to these Examples.
The analysis method is as follows.
<Analysis method>
1. 1. Differential scanning calorimetry (DSC)
2 to 3 mg of crystals were weighed on an aluminum pan, and measured using a differential scanning calorimetry device (manufactured by Shimadzu Corporation: DSC-60) using aluminum oxide as a control under the following operating conditions.
(Operating conditions)
Temperature rise rate: 10 ° C / min
Measurement temperature range: 30-260 ° C
Measurement atmosphere: open, nitrogen 50 mL / min
2. 2. Differential thermal / thermogravimetric analysis (DTG)
8 to 12 mg of crystals were weighed on an aluminum pan and measured using a differential thermal / thermogravimetric analyzer (manufactured by Shimadzu Corporation: DTG-60A) under the following operating conditions.
(Operating conditions)
Temperature rise rate: 10 ° C / min
Measurement temperature range: 30-300 ° C
Measurement atmosphere: open, nitrogen 50 mL / min
3. 3. Confirmation of reaction end point and purity measurement device: Prominence UFLC (liquid chromatograph) manufactured by Shimadzu Corporation
Graffiti)
Pump: LC-20AD
Column oven: CTO-20A
Detector: SPD-20A
Column: HALO C18 inner diameter 3mm, length 75mm
Oven temperature: 50 ° C
Flow rate: 0.7 ml / min
Mobile phase: (A) 0.1 wt% phosphoric acid aqueous solution, (B) acetonito
Lil gradient condition: (A) Volume% (time from the start of analysis)
<Reaction solution analysis>
70% (0min) → 100% (12min) → 100% (15min)
<Crystal analysis>
70% (0min) → 100% (12min) → 100% (15min)
Sample injection volume: 5 μl
Detection wavelength: 254nm
4. Refractive index device: Refractometer RA-500N manufactured by Kyoto Denshi Kogyo Co., Ltd.
For the compound to be measured, three samples of THF solution having an arbitrary concentration were prepared, and the refractive index of each solution was measured. The relationship between the concentration and the refractive index was derived with respect to the obtained value, the value at 100% concentration was calculated by extrapolation, and this value was taken as the refractive index of the compound.

<Synthesis example>
Synthesis of 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene A 1-liter 4-neck flask equipped with a thermometer, a stirrer, and a cooling tube was replaced with nitrogen, and 119 g (1.2 mol) of phenol was added. ) Was charged, hydrogen chloride gas was blown into the flask, and the inside of the flask was replaced with hydrogen chloride gas. 13 g of a 15% aqueous solution of methyl mercaptan sodium salt was added dropwise thereto, and then a mixture of 145 g (0.63 mol) of 2,3-benzo-9-fluorenone, 119 g (1.2 mol) of phenol and 58 g of toluene was added thereto for 1 hour. The mixture was added dropwise, and the mixture was stirred at a reaction temperature of 40 ° C. for 3 hours. The disappearance of the raw materials was confirmed by liquid chromatography analysis, and the reaction was terminated. An aqueous sodium hydroxide solution was added to the reaction mixture to neutralize the reaction solution, 60 g of toluene was added and the mixture was allowed to stand, and then the aqueous layer was removed. Distilled water was added to the obtained oil layer and stirred, and the operation of removing the aqueous layer after standing was repeated twice to remove the neutralized salt, and excess phenol was removed by vacuum distillation. Toluene was added to this distillation residue in an amount of 1009 g to form a uniform solution, which was then cooled to precipitate crystals. Then, the crystals were cooled to 25 ° C. and the precipitated crystals were filtered off to obtain 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene, which was the desired product.

<Example 1>
Synthesis of 9,9-bis (4-ethoxycarbonylmethoxyphenyl) -2,3-benzofluorene 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene 40.0 g (0.1 mol), 120 g of acetonitrile, 31.7 g of potassium carbonate, and 4.0 g of potassium iodide were placed in a four-necked flask, the temperature was raised to 70 ° C., and the mixture was stirred at the same temperature for 1 hour. Then, 34.3 g (0.28 mol) of ethyl chloroacetate was added dropwise while keeping the temperature of the reaction solution at 70 to 80 ° C. After stirring for 6 hours, 100 g of water was added and the temperature was raised to 70 ° C., and then the aqueous layer was removed. After that, acetonitrile was distilled off at normal pressure, 800 g of ethanol was added, the temperature was raised to 70 ° C., and then the temperature was cooled to 25 ° C. to precipitate crystals. The crystals were separated by filtration and dried to obtain 42.5 g of 9,9-bis (4-ethoxycarbonylmethoxyphenyl) -2,3-benzofluorene, which was the desired product. The figure which shows the differential scanning calorimetry (DSC) curve of the obtained crystal is shown in FIG.
Purity 99.2% (High Performance Liquid Chromatography)
Proton nuclear magnetic resonance spectrum (400 MHz, solvent CDCl ₃ , standard TMS)
Chemical shift (signal shape, number of protons): 1.26 ppm (t, 6H), 4.23 ppm (q, 4H), 4.54 ppm (s, 4H), 6.73-6.78 ppm (m, 4H), 7.14-7.19ppm (m, 4H), 7.28-7.33ppm (m, 1H), 7.36-7.47ppm (m, 4H), 7.75ppm (d, 2H), 7. 88-7.92 ppm (m, 2H), 8.17 (s, 1H).
From the differential scanning calorimetry (DSC) curve shown in FIG. 1, it was confirmed that the crystal had a peak top at 96 ° C. and 176 ° C. The refractive index was 1.620.

<Example 2>
Synthesis of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene / bispotassium salt 9,9-bis (4-ethoxycarbonylmethoxyphenyl) -2,3 obtained in Example 1 above -A solution of 40.0 g of benzofluorene in 120 g of acetonitrile was maintained at 70 to 80 ° C., 80.1 g of a 35% potassium hydroxide aqueous solution was added dropwise, and the mixture was stirred at the same temperature for 2 hours. The reaction mixture was cooled to 25 ° C., the obtained crystals were filtered off, and dried to obtain 56.5 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene / bispotassium salt crystals. did.
Purity 99.6% (High Performance Liquid Chromatography)
Proton nuclear magnetic resonance spectrum (400 MHz, solvent D ₂ O)
Chemical shift (signal shape, number of protons): 4.37 ppm (s, 4H), 6.75-6.83 ppm (m, 4H), 7.04-7.13 ppm (m, 4H), 7.25-7 .47 ppm (m, 5H), 7.63-7.73 ppm (m, 2H), 7.83-7.95 ppm (m, 2H), 8.12-8.23 ppm (m, 1H).
From the resulting FT-IR of a crystal, disappeared peak around 1700 cm ^-1 observed in carbonyl moiety of the carboxylic acid, confirmed the presence of around 1600 cm ^-1 observed in carboxylate and 1400 cm ^-1, the peak ..

<Example 3>
Synthesis of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene (1) Method for synthesizing seed crystals 9,9-bis (4-carboxymethoxyphenyl)-obtained in Example 2 above To 1.0 g of 2,3-benzofluorene / bispotassium salt, 3.0 g of methyl isobutyl ketone and 1 g of concentrated hydrochloric acid were added, the temperature was raised to 80 ° C., and then the aqueous layer was removed. 6.0 g of heptane was added to the obtained solution, cooled and the precipitate was filtered to obtain seed crystals.
(2) Synthesis method using seed crystals 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene / bispotassium salt 50.0 g, methyl isobutyl ketone 250 g, obtained in Example 2 above, 25.0 g of concentrated hydrochloric acid was added, and the mixture was stirred at 80 ° C. for 30 minutes. The aqueous layer was removed, water was added to the obtained oil layer, and the mixture was stirred to remove the aqueous layer. A washing operation was performed a plurality of times to remove the residual hydrochloric acid. 100.0 g of heptane was added to the obtained solution, 50 mg of the seed crystal obtained in (1) above was added at 75 ° C., and the mixture was cooled to 25 ° C. at a cooling rate of 10 ° C./hour and filtered. Then, it was dried to obtain 39.6 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene powder. FIG. 2 shows a diagram showing a differential scanning calorimetry (DSC) curve of the obtained crystal, and FIG. 3 shows a diagram showing a differential heat / thermogravimetric analysis (DTG) curve.
Yield 86.6% (Yield through 3 steps of Examples 1 to 3)
Purity 99.8% (High Performance Liquid Chromatography)
Proton nuclear magnetic resonance spectrum (400 MHz, solvent MeOH-d ₄ , standard TMS)
Chemical shift (signal shape, number of protons): 4.51 ppm (s, 4H), 6.71 ppm (d, 4H), 7.07 ppm (d, 4H), 7.22 ppm (dt, 1H), 7.31- 7.35ppm (m, 3H), 7.38ppm (dt, 1H), 7.65-7.69ppm (m, 2H), 7.86-7.90ppm (m, 2H), 8.18 (s,, 1H).
The refractive index was 1.658.
From the differential scanning calorimetry (DSC) curve shown in FIG. 2, it was confirmed that the crystal had a peak top at 176 ° C and 186 ° C. From the results of the DTG analysis shown in FIG. 3, it is inferred that the obtained crystal is an adduct crystal containing 2.0 wt% methyl isobutyl ketone because there is a weight loss at the melting point.
Results of NMR analysis, although OH peak of carboxylic acid was not observed, from the results of FT-IR, the peak in the vicinity of specific carbonyl group 1700 cm ^-1, the peak near the hydroxyl group-specific 3200 cm ^-1 were observed. From these facts, it was confirmed that the obtained crystal was the target product.
The target product is various general-purpose solvents in industrial applications, specifically, ketone solvents such as acetone and methylisobutylketone (MIBK), alcohol solvents such as methanol and butanol, tetrahydrofuran (THF) and cyclopentyl. It was confirmed that it has excellent solubility in an ether solvent such as methyl ether (CPME), an amide solvent such as N-methylpyrrolidone (NMP), and an ester solvent such as ethyl acetate and butyl acetate. As an example, the solubility of the obtained 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene in a solvent for adduct crystals containing methyl isobutyl ketone is shown in Table 1 below. "○" in Table 1 indicates that a 10 wt% solution can be easily prepared at room temperature.

<Example 4>
Synthesis of 9,9-bis (4-methoxycarbonylmethoxyphenyl) -2,3-benzofluorene 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene 15.0 g (0.037 mol), 45.0 g of acetonitrile, 11.9 g of potassium carbonate, and 1.5 g of potassium iodide were charged into a four-mouthed flask, heated to 70 ° C., and stirred at the same temperature for 1 hour. Then, 11.4 g (0.11 mol) of methyl chloroacetate was added dropwise while keeping the temperature of the reaction solution at 70 to 80 ° C. After stirring for 6 hours, 300 g of water was added, the temperature was raised to 70 ° C., and then cooled to 25 ° C. to precipitate crystals. The crystals were separated by filtration and dried to obtain 16.3 g of 9,9-bis (4-methoxycarbonylmethoxyphenyl) -2,3-benzofluorene, which was the desired product. FIG. 4 shows a diagram showing the differential scanning calorimetry (DSC) curve of the obtained crystal.
Purity 99.7% (High Performance Liquid Chromatography)
Proton nuclear magnetic resonance spectrum (400 MHz, solvent CDCl ₃ , standard TMS)
Chemical shift (signal shape, number of protons): 3.77 ppm (s, 6H), 4.56 ppm (s, 4H), 6.72-6.77 ppm (m, 4H), 7.14-7.19 ppm (m) , 4H), 7.28-7.32ppm (m, 1H), 7.36-7.47ppm (m, 4H), 7.75ppm (d, 2H), 7.87-7.92ppm (m, 2H) ), 8.17 (s, 1H).
From the differential scanning calorimetry (DSC) curve shown in FIG. 4, it was confirmed that the crystal had a peak top at 155 ° C. The refractive index was 1.621.

<Example 5>
Synthesis of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene-bissodium salt 9,9-bis (4-ethoxycarbonylmethoxyphenyl) -2,3 obtained in Example 1 above -A solution of 10.0 g of benzofluorene in 30 g of acetonitrile was maintained at 70 to 80 ° C., 5.0 g of water and 7.3 g of a 48% sodium hydroxide aqueous solution were added dropwise, and the mixture was stirred at the same temperature for 2 hours. The reaction mixture was cooled to 25 ° C., the obtained crystals were filtered off, and dried to obtain 8.5 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene / bissodium salt crystals. did.
Purity 99.6% (High Performance Liquid Chromatography)
Proton nuclear magnetic resonance spectrum (400 MHz, solvent D ₂ O)
Chemical shift (signal shape, number of protons): 4.37 ppm (s, 4H), 6.75-6.87 ppm (m, 4H), 7.05-7.13 ppm (m, 4H), 7.30-7 .52 ppm (m, 5H), 7.70-7.78 ppm (m, 2H), 7.93-8.01 ppm (m, 2H), 8.27 ppm (s, 1H).
From the resulting FT-IR of a crystal, disappeared peak around 1700 cm ^-1 observed in carbonyl moiety of the carboxylic acid, confirmed the presence of around 1600 cm ^-1 observed in carboxylate and 1400 cm ^-1, the peak ..

<Example 6>
Synthesis of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene (reaction solvent: MIBK)
Put 9,9-bis (4-hydroxyphenyl) -2,3-benzofluorene 400 g (1.0 mol), methyl isobutyl ketone 1500 g, potassium carbonate 370 g, and potassium iodide 12 g into a four-necked flask and reduce the pressure to 95. 700 g of methyl isobutyl ketone was distilled off at ° C. The inside of the reaction system was returned to normal pressure with nitrogen, and then 405 g (3.3 mol) of ethyl chloroacetate was added dropwise while keeping the temperature of the reaction solution at 90 to 100 ° C. After stirring at the same temperature for 18 hours, 1900 g of water was added and the temperature was raised to 80 ° C., and then the aqueous layer was removed. 2200 g of methyl isobutyl ketone was added to the reaction solution, and then 333 g of a 48% sodium hydroxide aqueous solution was added dropwise while keeping the temperature of the reaction solution at 70 to 80 ° C., and the mixture was stirred at the same temperature for 5 hours. Then, under reduced pressure, 1200 g of methyl isobutyl ketone was distilled off at 70 to 80 ° C., 1000 g of water and 520 g of concentrated hydrochloric acid were added, and the mixture was stirred at 70 to 80 ° C. for 1 hour.
The aqueous layer was removed, water was added to the obtained oil layer, and the mixture was stirred to remove the aqueous layer. A washing operation was performed a plurality of times to remove the residual hydrochloric acid. 750 g of methyl isobutyl ketone was distilled off from the obtained solution under reduced pressure, 500 g of heptane was added to the residue, 50 mg of seed crystals were added at 73 ° C., and the mixture was cooled to 25 ° C. at a cooling rate of 10 ° C./hour and filtered. , 9-Bis (4-carboxymethoxyphenyl) -2,3-benzofluorene crude crystals were obtained in 749.6 g. 710 g of the obtained crude crystals, 1420 g of toluene, and 710 g of water were placed in a four-necked flask, stirred under heating and reflux for 2 hours, cooled to 25 ° C. at a cooling rate of 10 ° C./hour, filtered, and dried. 432.6 g of 9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene crystals was obtained. The purity was 99.6% and the yield was 83.7%.

Since adduct crystals were obtained in Example 3, the polymorphs of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene were examined in Examples 7 to 10 below.
<Example 7>
2.0 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene and 8.0 g of toluene obtained in Example 3 above were stirred at 90 ° C. for 1 hour, cooled to 25 ° C., and filtered. Crystals were obtained by separating. FIG. 5 shows a diagram showing a differential thermal / thermogravimetric analysis (DTG) curve of the obtained crystals.
From the differential thermal / thermogravimetric analysis (DTG) curve of the crystal shown in FIG. 5, it was confirmed that the crystal had a single peak top at 200 ° C., and the adduct containing the methyl isobutyl ketone obtained in Example 3 was confirmed. Unlike crystals, no weight loss was observed at the melting point, suggesting that they are single crystals.

<Example 8>
Add 2.0 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene, 8.0 g of toluene and 1.0 g of water obtained in Example 3 above, and stir for 1 hour under heating and reflux 25. Crystals were obtained by cooling to ° C and filtering. FIG. 6 shows a diagram showing a differential thermal / thermogravimetric analysis (DTG) curve of the obtained crystals.
From the differential thermal / thermogravimetric analysis (DTG) curve shown in FIG. 6, it was confirmed that the crystal had a single peak top at 202 ° C., and the crystal was found to contain the methyl isobutyl ketone obtained in Example 3 and the adduct crystal. Unlike, no weight loss was observed at the melting point, suggesting that it is a single crystal.

<Example 9>
2.0 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene and 4.0 g of butyl acetate obtained in Example 3 above were stirred at 90 ° C. for 1 hour to obtain a uniform solution. After that, 4.0 g of heptane was added, the mixture was cooled to 25 ° C., and the mixture was filtered off to obtain crystals. FIG. 7 shows a diagram showing a differential thermal / thermogravimetric analysis (DTG) curve of the obtained crystals.
From the differential thermal / thermogravimetric analysis (DTG) curve shown in FIG. 7, it was confirmed that the crystal had a single peak top at 198 ° C, and the crystal was found to contain the methyl isobutyl ketone obtained in Example 3. Unlike, no weight loss was observed at the melting point, suggesting that it is a single crystal.

<Example 10>
After stirring 2.0 g of 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene and 8.0 g of acetonitrile obtained in Example 3 at 80 ° C. for 1 hour to obtain a uniform solution. Crystals were obtained by cooling to 25 ° C. and filtering. FIG. 8 shows a diagram showing a differential thermal / thermogravimetric analysis (DTG) curve of the obtained crystals.
From the differential thermal / thermogravimetric analysis (DTG) curve shown in FIG. 8, it was confirmed that the crystal had a peak top at 94 ° C. and 145 ° C. It was also confirmed that acetonitrile was released from the adduct crystal at the peak top at 94 ° C.

Similarly, for the single crystals obtained in Examples 7 to 9, various general-purpose solvents for industrial use, specifically, ketone solvents such as acetone and methylisobutylketone (MIBK), methanol, butanol and the like, etc. Excellent solubility in alcohol solvents, ether solvents such as tetrahydrofuran (THF) and cyclopentylmethyl ether (CPME), amide solvents such as N-methylpyrrolidone (NMP), and ester solvents such as ethyl acetate and butyl acetate. It was confirmed that As an example, the solubility of the obtained 9,9-bis (4-carboxymethoxyphenyl) -2,3-benzofluorene in a solvent for a single crystal is shown in Table 2 below. "○" in Table 2 indicates that a 10 wt% solution can be easily prepared at room temperature.
From the results of Tables 1 and 2, it was confirmed that there is no difference in the solubility of the fluorene compound represented by the general formula (1) of the present invention in the solvent between the single crystal and the adduct crystal. It is considered that this is largely related to the solvent solubility of the fluorene compound itself represented by the general formula (1) of the present invention.

While it is known that compounds having a fluorene skeleton form adduct crystals with a reaction solvent or a solvent used for purification, it takes a large amount of time and high temperature to remove the solvent from the adduct crystals. In short, it is difficult to apply on an industrial scale, and compounds having a fluorene skeleton that forms adduct crystals with a solvent are industrially used in manufacturing raw materials such as epoxy resins and polyesters and other uses. Is also known to have problems. Further, depending on the flash point or ignition point of a compound such as an organic solvent contained in the adduct crystal, there is a concern about disaster prevention during transportation or storage of the adduct crystal. Considering these points, it is considered that the method for obtaining a fluorene compound represented by the general formula (1) of a single crystal other than an adduct crystal is also very useful in industrial applications.

Claims (1)

A fluorene compound represented by the following general formula (1).

(In the formula, R ₁ and R ₂ are independent hydrogen atoms, alkyl groups having 1 to 6 carbon atoms, alkali metal atoms, alkaline earth metal atoms, and R ₃ and R ₄ are independent carbon atoms, respectively. alkyl group of 1 -C 6, phenyl group, _{R 5} and _{R 6} are each independently a hydrogen atom, a halogen atom, an alkyl group having 1 to 6 carbon atoms, an alkenyl group having 2 to 6 carbon atoms, a carbon It represents an alkoxy group having 1 to 6 atoms and an aryl group having 6 to 12 carbon atoms, where a, b and c independently represent an integer of 0 to 4, and d represents an integer of 0 to 6).

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