JP2024062143A - Method for producing aromatic bisether compound - Google Patents

Abstract

[Problem] The objective of the present invention is to provide a new method for producing an aromatic bisether compound, which can shorten the reaction time. [Solution] A method for producing an aromatic bisether compound represented by formula (3), which comprises reacting an aromatic dihydroxy compound (1) represented by formula (1), a halide (2) represented by formula (2), and an alkali metal carbonate or alkali metal hydrogen carbonate while introducing an inert gas and discharging gas from within the reaction system. [Selected Figure] None

Description

The present invention relates to a method for producing an aromatic bisether compound.

Dicarboxylic acid compounds having an aromatic bisether skeleton are used as raw materials for polyamides, raw materials for allyl ester compounds, and additives such as plasticizers and curing agents, and dicarboxylic acid compounds having an aromatic bisether skeleton that use bisphenol compounds as raw materials are also known (Patent Documents 1 and 2, etc.).
Many methods for synthesizing a dicarboxylic acid component having an aromatic bis-ether skeleton are known, which involve reacting an aromatic dihydroxy compound with a halide. For example, it has been reported that 2,2'-bis(2-ethoxycarbonylmethoxy)-1,1'-binaphthyl can be obtained by reacting 1,1'-binaphthalene-2,2'-diol with a halogenated acetate such as ethyl chloroacetate and hydrolyzing the resulting compound (Patent Documents 3 and 4).

Japanese Patent Application Laid-Open No. 62-292819 Japanese Patent Application Laid-Open No. 05-170702 JP 2018-059074 A JP 2008-024650 A

The prior art including the above-mentioned Patent Documents 1 and 2 has not been studied with the industrial production of the aromatic bisether compound according to the present invention in mind.
On the other hand, the present inventors have found that when the aromatic bisether compound according to the present invention is produced industrially, the reaction time is long, which causes a problem in production efficiency.
The present invention has been made in light of the above-mentioned circumstances, and an object of the present invention is to provide a new method for producing an aromatic bisether compound, which can shorten the reaction time.

As a result of various investigations aimed at shortening the reaction time, the inventors discovered that the reaction time could be shortened by introducing an inert gas and carrying out the reaction while discharging the gas from within the reaction system, and thus completed the present invention.

The present invention will now be described.
1. A method for producing an aromatic bisether compound represented by the following formula (3), which comprises reacting an aromatic dihydroxy compound (1) represented by the following formula (1), a halide (2) represented by the following formula (2), and an alkali metal carbonate or an alkali metal hydrogen carbonate while introducing an inert gas and discharging gas from within the reaction system.

In formula (1), Ar ₁ and Ar ₂ each independently represent a benzene ring or a naphthalene ring, R ₁ each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, n each independently represent an integer of 0 to 4, and X each independently represent a single bond or a divalent group represented by any one of the following formulas (1a) and (1b):

In formulae (1a) and (1b), R ₂ 's each independently represent hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms; R ₂ 's may be bonded to each other to form a cycloalkylidene group having 5 to 20 carbon atoms as a whole; Ar ₃ and Ar ₄ each independently represent a benzene ring or a naphthalene ring; and * indicates the bonding position with Ar ₁ or Ar ₂ , respectively.

In formula (2), Y represents a halogen atom, and A represents one group selected from a linear or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group having 1 to 10 carbon atoms, a glycidyl group, an aryl group having 6 to 12 carbon atoms, and a group represented by the following formula (2a) or the following formula (2b):

(In formula (2a), _R4 represents a linear or branched alkylene group having 1 to 4 carbon atoms, _R5 represents a linear or branched alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and * represents the bonding position with Y.)

(In formula (2b), _R6 represents a linear or branched alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and * represents the bonding position with Y.)

(In formula (3), Ar ₁ , Ar ₂ , R ₁ , n, and X are the same as those in formula (1), and A is the same as that in formula (2).)
2. The method for producing an aromatic bisether compound according to 1., wherein the inert gas is introduced at a flow rate of 20 to 120 L per hour relative to 1 mole of the aromatic dihydroxy compound (1).
3. The method for producing an aromatic bisether compound according to 1., wherein X in the formula (1) and the formula (3) is a single bond.
4. The method for producing an aromatic bisether compound according to 1. or 2., wherein Ar ₁ and Ar ₂ in the formula (1) and the formula (3) are both naphthalene rings.
5. The method for producing an aromatic bisether compound according to 3., wherein R ₅ in the formula (2a) is a linear or branched alkyl group having 1 to 10 carbon atoms.

According to the present invention, aromatic bisether compounds can be produced with high production efficiency because the reaction time is short.

The present invention will be described in detail below.
<Aromatic dihydroxy compound (1)>
One of the starting materials used in the production method of the present invention is an aromatic dihydroxy compound represented by the following formula (1) (hereinafter referred to as "aromatic dihydroxy compound (1)").

In formula (1), Ar ₁ and Ar ₂ each independently represent a benzene ring or a naphthalene ring, R ₁ each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, n each independently represent an integer of 0 to 4, and X each independently represent a single bond or a divalent group represented by any one of the following formulas (1a) and (1b):

(In formulas (1a) and (1b), each R ₂ independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms; R ₂ may be bonded to each other to form a cycloalkylidene group having 5 to 20 carbon atoms as a whole; Ar ₃ and Ar ₄ independently represent a benzene ring or a naphthalene ring; and * represents the bonding position with Ar ₁ or Ar ₂ , respectively.)

In formula (1), Ar ₁ and Ar ₂ each represent a benzene ring or a naphthalene ring. Of these, a naphthalene ring is preferred, and it is particularly preferred that both Ar ₁ and Ar ₂ are naphthalene rings.
In formula (1), R ₁ each independently represents a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Among them, a linear or branched alkyl group having 1 to 6 carbon atoms or an aryl group having 6 to 12 carbon atoms is preferred. As the linear or branched alkyl group having 1 to 6 carbon atoms, an alkyl group having 1 to 4 carbon atoms is preferred, and an alkyl group having 1 to 2 carbon atoms is more preferred. Specific examples of the alkyl group include a methyl group, an ethyl group, an n-propyl group, an isopropyl group, an n-butyl group, a t-butyl group, an n-pentyl group, and a 2-methylpentyl group. As the aryl group having 6 to 12 carbon atoms, an alkyl group having 1 to 5 carbon atoms may be substituted, and the number of carbon atoms includes the number of carbon atoms of the substituted alkyl group, and specific examples include a 4-methylphenyl group, a 4-isopropylphenyl group, a phenyl group, and a naphthyl group.
In formula (1), n's each independently represent an integer of 0 to 4, preferably an integer of 0 to 3, more preferably an integer of 0 to 2, still more preferably 0 or 1, and particularly preferably 0.
X in formula (1) represents a single bond or a divalent group represented by any one of the following formulas (1a) and (1b). Among them, a single bond or a divalent group represented by formula (1a) is preferable, and a single bond is more preferable.

When X in formula (1) is a single bond, the aromatic dihydroxy compound (1) is represented by the following formula (1-1).

(In the formula, Ar ₁ , Ar ₂ , R ₁ , and n are the same as those in formula (1).)
Furthermore, when both Ar ₁ and Ar ₂ are phenylene groups, it is represented by the following formula (1-2).

(In the formula, R ₁ and n are the same as those in formula (1).)
The bonding position of the OH group in the above formula (1-2) is preferably the ortho-position or para-position relative to the bonding position between the benzene rings, and particularly preferably the para-position.
The bonding position of the group represented by R ₁ in the above formula (1-2) is preferably the meta position with respect to the bonding positions between the benzene rings.
In the above formula (1-1), one embodiment in which both Ar ₁ and Ar ₂ are naphthalene rings is represented by the following formula (1-3).

(In the formula, R ₁ and n are the same as those in formula (1).)
The bonding position of the OH group in the above formula (1-3) is preferably the 2- or 4-position of the naphthalene ring, and particularly preferably the 2-position.
The bonding position of the group represented by R ₁ in the above formula (1-3) is preferably the 3-position or 6-position of the naphthalene ring, and more preferably the 6-position.

Specific examples of the aromatic dihydroxy compound (1) in the present invention include biphenyl-4,4'-diol, 3,3'-dimethyl-biphenyl-4,4'-diol, 3,3'-diethyl-biphenyl-4,4'-diol, 3,3',5,5'-tetramethyl-biphenyl-4,4'-diol, 3,3',6,6'-tetramethyl-biphenyl-4,4'-diol, 3,3'-dimethyl-5,5'-di-t-butyl-biphenyl-4,4'-diol, fluorene, 3,3',5,5'-tetra-t-butyl-biphenyl-4,4'-diol, 3,3'-diphenyl-biphenyl-4,4'-diol, 1,1'-binaphthalene-2,2'-diol, 2,2'-binaphthalene-1,1'-diol, 1,1'-binaphthalene-6,6'-diphenyl-2,2'-diol, 9,9-bis(4-hydroxyphenyl)fluorene, and 9,9-bis(4-hydroxyphenyl)-2,3-benzofluorene. Among these, biphenyl-4,4'-diol, 3,3'-dimethyl-biphenyl-4,4'-diol, 3,3',5,5'-tetramethyl-biphenyl-4,4'-diol, and 1,1'-binaphthalene-2,2'-diol are preferred, and 1,1'-binaphthalene-2,2'-diol represented by the following formula (A) is particularly preferred.

When X in formula (1) is formula (1a), R ₂ each independently represents hydrogen, an alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms. Among them, hydrogen, an alkyl group having 1 to 6 carbon atoms, and an aryl group having 6 to 8 carbon atoms are preferred, and hydrogen, an alkyl group having 1 to 4 carbon atoms, or a phenyl group are more preferred. In addition, R ₂ may be bonded to each other to form a cycloalkylidene group having 5 to 20 carbon atoms as a whole. The cycloalkylidene group having 5 to 20 carbon atoms may contain an alkyl group as a branched chain. The cycloalkylidene group preferably has 5 to 15 carbon atoms, more preferably has 6 to 12 carbon atoms, and particularly preferably has 6 to 9 carbon atoms. Specific examples of the cycloalkylidene group include a cyclopentylidene group (5 carbon atoms), a cyclohexylidene group (6 carbon atoms), a 3-methylcyclohexylidene group (7 carbon atoms), a 4-methylcyclohexylidene group (7 carbon atoms), a 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), a cycloheptylidene group (7 carbon atoms), and a cyclododecanylidene group (12 carbon atoms). Preferred are a cyclohexylidene group (6 carbon atoms), a 3-methylcyclohexylidene group (7 carbon atoms), a 4-methylcyclohexylidene group (7 carbon atoms), a 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), and a cyclododecanylidene group (12 carbon atoms), and more preferred are a cyclohexylidene group (6 carbon atoms), a 3,3,5-trimethylcyclohexylidene group (9 carbon atoms), and a cyclododecanylidene group (12 carbon atoms).
In formula (1b), it is more preferable that both Ar ₃ and Ar ₄ are benzene rings. For example, when both Ar ₃ and Ar ₄ are benzene rings, the group represented by formula (1b) is a fluorenylidene group.

<Halide (2)>
One of the starting materials used in the production method of the present invention is a halide represented by the following formula (2) (hereinafter referred to as "halide (2)").

In formula (2), Y represents a halogen atom, and A represents one group selected from a linear or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group having 1 to 10 carbon atoms, a glycidyl group, an aryl group having 6 to 12 carbon atoms, and a group represented by the following formula (2a) or the following formula (2b):

(In formula (2a), _R4 represents a linear or branched alkylene group having 1 to 4 carbon atoms, _R5 represents a linear or branched alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and * represents the bonding position with Y.)

(In formula (2b), _R6 represents a linear or branched alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and * represents the bonding position with Y.)

In formula (2), Y represents a halogen atom, specifically, for example, a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom. Among these, a chlorine atom and a bromine atom are preferred, and a chlorine atom is particularly preferred.
In formula (2), A is preferably formula (2a), and R ₄ in formula (2a) is preferably an alkylene group having 1 to 2 carbon atoms, more preferably an alkylene group having 1 carbon atom, i.e., a methylene group.
_R5 in formula (2a) is preferably a linear or branched alkyl group having 1 to 10 carbon atoms, more preferably a linear or branched alkyl group having 1 to 4 carbon atoms, still more preferably an alkyl group having 1 to 2 carbon atoms, and particularly preferably an ethyl group, which is an alkyl group having 2 carbon atoms. As the alkenyl group having 2 to 10 carbon atoms, an alkenyl group having 2 to 4 carbon atoms is preferable, and examples thereof include an ethynyl group, a 2-propynyl group, and a 1-propynyl group.
When A in formula (2) is a linear or branched alkyl group having 1 to 10 carbon atoms, it is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, more preferably a linear alkyl group having 1 to 4 carbon atoms, and even more preferably a methyl group. Specific examples of the cyclic alkyl group having 1 to 10 carbon atoms for A include a cyclopentyl group, a cyclohexyl group, a cycloheptyl group, a cyclooctyl group, a 1-adamantyl group, and a 2-adamantyl group. In addition, examples of the aryl group having 6 to 12 carbon atoms include a phenyl group (6 carbon atoms), a 4-methylphenyl group (7 carbon atoms), and a 4-nitrophenyl group (6 carbon atoms), which may have a substituent such as an alkyl group or a nitro group.
R ₆ in the formula (2b) is preferably a linear or branched alkyl group having 1 to 4 carbon atoms, such as a methyl group or an ethyl group.
Specific examples of the halide (2) represented by formula (2) include, for example, methyl chloroacetate, ethyl chloroacetate, propyl chloroacetate, methyl bromoacetate, ethyl bromoacetate, propyl bromoacetate, methyl iodoacetate, ethyl iodoacetate, and propyl iodoacetate.

<Aromatic bisether compound (3)>
The target compound in the production method of the present invention is an aromatic bisether compound represented by the following formula (3) (hereinafter referred to as "aromatic bisether compound (3)").

(In formula (3), Ar ₁ , Ar ₂ , R ₁ , n, X, and A are the same as those in formulas (1) and (2).)
Specific examples and preferred examples of Ar ₁ , Ar ₂ , R ₁ , n, and X in the above formula (3) are the same as those in formula (1), and specific examples and preferred examples of A in the above formula (3) are the same as those in formula (2).

In the aromatic bisether compound represented by the above formula (3), when X is a single bond, which is a particularly preferred embodiment, the compound is represented by the following formula (3-1).

(In the formula, Ar ₁ , Ar ₂ , R ₁ , n, and A are the same as those in formulas (1) and (2).)
In the compound represented by the above formula (3-1), when Ar ₁ and Ar ₂ are both phenylene groups, the compound is represented by the following formula (3-2).

(In the formula, R ₁ , n, and A are the same as those in formulas (1) and (2).)
Regarding the compound represented by the above formula (3-1), one embodiment in which Ar ₁ and Ar ₂ are both naphthalene rings is represented by the following formula (3-3).

(In the formula, R ₁ , n, and A are the same as those in formulas (1) and (2).)

Specific examples of the compound represented by the above formula (3-1) include 4,4'-bis(methoxycarbonylmethoxy)-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3'-dimethyl-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3'-dimethyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3'-diethyl-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3'-diethyl-biphenyl, and 4,4'-bis(ethoxycarbonylmethoxy)-3,3'-diphenyl. Diethyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3',5,5'-tetramethyl-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3',5,5'-tetramethyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3',6,6'-tetramethyl-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3',6,6'-tetramethyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3'-dimethyl-5,5'-di -t-butyl-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3'-dimethyl-5,5'-di-t-butyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3',5,5'-tetra-t-butylbiphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3',5,5'-tetra-t-butylbiphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-3,3'-diphenyl-biphenyl, 2,2'-bis(methoxycarbonylmethoxy)-1,1'-binaphthyl , 2,2'-bis(ethoxycarbonylmethoxy)-1,1'-binaphthyl, 2,2'-bis(propoxycarbonylmethoxy)-1,1'-binaphthyl, 1,1'-bis(ethoxycarbonylmethoxy)-2,2'-binaphthyl, 2,2'-bis(ethoxycarbonylmethoxy)-6,6'-diphenyl-1,1'-binaphthalene, 9,9-bis[4-(ethoxycarbonylmethoxy)phenyl]fluorene, and 9,9-bis[4-(ethoxycarbonylmethoxy)phenyl]-2,3-benzofluorene.
Among these, 4,4'-bis(methoxycarbonylmethoxy)-biphenyl, 4,4'-bis(ethoxycarbonylmethoxy)-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3'-dimethyl-biphenyl, 4,4'-bis(methoxycarbonylmethoxy)-3,3',5,5'-tetramethyl-biphenyl, 2,2'-bis(methoxycarbonylmethoxy)-1,1'-binaphthyl, 2,2'-bis(ethoxycarbonylmethoxy)-1,1'-binaphthyl, and 2,2'-bis(ethoxycarbonylmethoxy)-6,6'-diphenyl-1,1'-binaphthalene are preferred, and 2,2'-bis(methoxycarbonylmethoxy)-1,1'-binaphthyl and 2,2'-bis(ethoxycarbonylmethoxy)-1,1'-binaphthyl are particularly preferred.

<Alkali metal carbonates, alkali metal hydrogen carbonates>
Examples of the alkali metal carbonate include lithium carbonate, sodium carbonate, potassium carbonate, etc., and examples of the alkali metal hydrogen carbonate include sodium hydrogen carbonate, potassium hydrogen carbonate, etc. Among these, the alkali metal carbonate is preferred, sodium carbonate and potassium carbonate are more preferred, and potassium carbonate is even more preferred.

<Inert gas>
In the production method of the present invention, an inert gas is introduced and the gas is discharged outside the reaction system. In the production method of the present invention, the carbon dioxide gas generated by the reaction can be discharged outside the reaction system by introducing the inert gas, so that the reaction is promoted and the reaction time is shortened. In the production method of the present invention, it is preferable that the reaction system is replaced with nitrogen, and then the halide (2) is dropped into the reaction system, and after the dropping is completed, the reaction is carried out while introducing the inert gas.
In the production method of the present invention, the amount of inert gas introduced per hour per mole of aromatic dihydroxy compound (1) is preferably in the range of 20 to 120 L (corresponding to a range of about 333 to 2000 mL per minute), more preferably in the range of 34 to 89 L (corresponding to a range of about 567 to about 1483 mL per minute), even more preferably in the range of 48 to 76 L (corresponding to a range of 800 to about 1267 mL per minute), and particularly preferably in the range of 55 to 69 L (corresponding to a range of about 917 to 1150 mL per minute).
In the manufacturing method of the present invention, it is preferable that the flow rate of the inert gas is constant, but it does not have to be constant, and there may be fluctuations within the above-mentioned flow rate range, or the flow rate may temporarily be outside the range, as long as the amount introduced per hour is within the above-mentioned range.
In the production method of the present invention, the total amount of the inert gas introduced from the start of the reaction to the end of the reaction is preferably in the range of 200 to 1,200 L, more preferably in the range of 340 to 890 L, still more preferably in the range of 480 to 760 L, and particularly preferably in the range of 550 to 690 L, relative to 1 mole of the aromatic dihydroxy compound (1) used in the reaction.
The type of inert gas used in the production method of the present invention is not particularly limited as long as it does not inhibit the reaction, but does not include carbon dioxide.Specific examples include nitrogen gas, argon gas, helium gas, and a mixed gas of nitrogen gas and air, and the mixed gas of nitrogen gas and air preferably has an oxygen content of 6% by volume or less, more preferably 4% by volume or less.The inert gas used in the production method of the present invention is preferably nitrogen, argon, or helium, and most preferably nitrogen gas.
In the production method of the present invention, the inert gas may be introduced into either the gas phase or the liquid phase in the reaction vessel, but it is preferable to introduce the inert gas into the gas phase, and more preferably to introduce the gas into the vicinity of the reaction liquid surface.

<Exhaust gas>
In the production method of the present invention, it is preferable to carry out the reaction while discharging the gas in the reaction system (inside the reaction vessel), and the discharge amount per hour for 1 mole of aromatic dihydroxy compound (1) is preferably in the range of 20 to 120 L (about 333 to 2000 mL per minute), preferably in the range of 34 to 89 L (corresponding to a range of about 567 to about 1483 mL per minute), more preferably in the range of 48 to 76 L (corresponding to a range of 800 to about 1267 mL per minute), and particularly preferably in the range of 55 to 69 L (corresponding to a range of about 917 to 1150 mL per minute). The flow rate of this discharge gas is preferably constant, but does not need to be constant, and may fluctuate within the above flow rate range, or may be temporarily outside the range, as long as the discharge amount per hour is within the above range. In addition, it is more preferable that the discharge point is far from the reaction liquid surface. Furthermore, the total amount of gas discharged from the start of the reaction to the end of the reaction is preferably in the range of 200 to 1200 L, more preferably in the range of 340 to 890 L, further preferably in the range of 480 to 760 L, and particularly preferably in the range of 550 to 690 L, per mole of aromatic dihydroxy compound (1) used in the reaction. The location of the gas discharge port is preferably a location far from the introduction location of the inert gas or a location far from the liquid surface.

<Amount of raw materials used>
In the production method of the present invention, the amount of the halide (2) used is not particularly limited as long as it is a theoretical value of 2.0 moles or more per mole of the aromatic dihydroxy compound (1) as the raw material, but is usually 2 moles or more, preferably in the range of 2.0 to 2.5 moles, and more preferably in the range of 2.05 to 2.15 moles.

<Catalyst>
In the production method of the present invention, in order to further improve production efficiency, it is preferable to carry out the reaction in the presence of an iodide salt such as an alkali metal iodide or ammonium iodide.
Specific examples include potassium iodide, sodium iodide, tetraalkylammonium iodide, tetraarylammonium iodide, tetraarylalkylammonium iodide, etc. These may be used alone or in combination of two or more kinds.
The amount of the iodide salt used is preferably in the range of 2 to 20 parts by weight, more preferably in the range of 2 to 10 parts by weight, and even more preferably in the range of 2 to 5 parts by weight, based on 100 parts by weight of the aromatic dihydroxy compound (1) as the raw material.

<Reaction Solvent>
As the solvent that can be used in the production method of the present invention, it is preferable to use an aprotic polar solvent. Specifically, for example, a chain aliphatic ketone having 5 to 8 carbon atoms such as diethyl ketone (carbon number 5), methyl isobutyl ketone (carbon number 6), methyl amyl ketone (carbon number 7), methyl hexyl ketone (carbon number 8), etc., a chain nitrile solvent having 2 to 6 carbon atoms such as acetonitrile and propanenitrile, an ether solvent such as dibutyl ether, an ester solvent such as ethyl acetate, dimethylformamide, dimethylsulfoxide, etc. can be mentioned. Among these, from the viewpoint of reaction rate, a chain aliphatic ketone having 5 to 8 carbon atoms, a chain nitrile solvent having 2 to 6 carbon atoms, dimethylformamide, dimethylsulfoxide are more preferable, and a chain aliphatic ketone having 5 to 8 carbon atoms is more preferable because it has low solubility in water and facilitates a water washing treatment to remove a base used during the reaction, and a chain aliphatic ketone having 6 to 7 carbon atoms is particularly preferable. These solvents may be used alone or in a mixture of two or more kinds.
The amount of the solvent used in the reaction is preferably in the range of 120 to 1,000 parts by weight, more preferably in the range of 150 to 800 parts by weight, and further preferably in the range of 150 to 600 parts by weight, per 100 parts by weight of the aromatic dihydroxy compound (1).
In the present invention, the reaction may be carried out while distilling off the solvent, and in this case, the amount of the solvent used in the reaction is preferably in the range of 200 to 2000 parts by weight, more preferably in the range of 300 to 1000 parts by weight, even more preferably in the range of 350 to 800 parts by weight, and particularly preferably in the range of 400 to 600 parts by weight, relative to 100 parts by weight of the aromatic dihydroxy compound (1). The amount of the solvent to be distilled off is preferably in the range of 50 to 600 parts by weight, more preferably in the range of 100 to 500 parts by weight, and even more preferably in the range of 200 to 400 parts by weight, relative to 100 parts by weight of the aromatic dihydroxy compound (1).

<Use form and amount of alkali metal carbonate and alkali metal hydrogen carbonate>
In the production method of the present invention, it is preferable to form a salt of the aromatic dihydroxy compound (1) with an alkali metal carbonate or an alkali metal hydrogencarbonate to enhance the nucleophilicity thereof and then react the salt with the halide (2).
The amount of the alkali metal carbonate or alkali metal hydrogen carbonate used is preferably in the range of 2.0 to 2.5 mol, more preferably 2.05 to 2.15 mol, per mol of the aromatic dihydroxy compound (1).

<Reaction conditions>
The reaction temperature in the present invention is usually preferably in the range of 60 to 100° C., more preferably in the range of 80 to 90° C., and particularly preferably 80° C. If the reaction temperature is high, the yield of the target aromatic bisether compound (3) decreases, particularly due to hydrolysis, and is therefore undesirable. If the reaction temperature is low, the reaction rate becomes slow, which is undesirable.

According to the method of the present invention, it is possible to promote the production of an aromatic monoether compound represented by the following formula (3'), which is a reaction intermediate, from the raw material, and the conversion of this reaction intermediate aromatic monoether compound to the target aromatic bisether compound, thereby shortening the reaction time.

(In formula (3'), Ar ₁ , Ar ₂ , R ₁ , n, X, and A are the same as those in formulas (1) and (2).)

End of reaction
The end point of the reaction can be confirmed by liquid chromatography or gas chromatography analysis. The end point of the reaction is preferably the time when the increase in the target aromatic bisether compound (3) is no longer observed or when the remaining amount of the aromatic monoether compound (composition value by high performance liquid chromatography) becomes a trace amount (preferably 0.2 area % or less). The reaction time varies depending on the reaction conditions such as the reaction temperature, but is completed within about 1 to 30 hours. Among them, an embodiment in which the reaction is completed within about 4 to 10 hours is preferable.
After the reaction is completed, water is added to the reaction solution, the mixture is stirred, and the mixture is left to stand to separate the aqueous layer. This washing operation is preferably carried out twice or more times to remove or significantly reduce inorganic salts in the reaction solution. The amount of water used in each washing operation is preferably in the range of 50 to 600 parts by weight, more preferably in the range of 50 to 400 parts by weight, based on 100 parts by weight of the aromatic dihydroxy compound (1) used. The temperature is preferably in the range of 60 to 100°C, more preferably in the range of 70 to 90°C. As for the stirring, it is sufficient that the oil layer is in sufficient contact with the aqueous layer, and although the required time varies depending on the apparatus, about 30 minutes is usually sufficient. It is preferable to purify and isolate the target aromatic bisether compound (3) from the oil layer after the washing operation. For example, the target aromatic bisether compound (3) can be obtained by carrying out post-treatment operations such as crystallization, filtration, distillation, and separation by column chromatography after the washing operation 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. The operations after the completion of the reaction are also preferably carried out in an inert gas atmosphere or in an atmosphere with a low oxygen concentration, and an inert gas atmosphere is more preferable.

The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples.
The analysis method is as follows.
<Analysis method>
1. Confirmation of the composition of aromatic monoether compounds and the target aromatic bisether compounds in the reaction solution and the reaction end point Measurement equipment: High performance liquid chromatography analyzer (Shimadzu Corporation)
Pump: LC-20AD
Column oven: CTO-20A
Detector: SPD-20A
Column: HALO-C18
Oven temperature: 50°C
Flow rate: 0.7 mL/min
Detection wavelength: 280 nm
Gradient conditions Mobile phase: (A) 0.2 vol% acetic acid aqueous solution, (B) methanol (B) volume % (time from start of analysis)
50% (0 minutes) → 100% (10 minutes) → 100% (13 minutes)
The reaction solution was measured under the above conditions, and the reaction was deemed to be terminated when the amount of aromatic monoether compounds relative to the total amount of all detected components was 0.2 area % or less.

Example 1
The reaction shown in the following reaction formula was carried out. The detailed procedure is as follows.
50.0 g (0.17 mol) of 1,1'-binaphthalene-2,2'-diol (A), an aromatic dihydroxy compound, 125.2 g of methyl isobutyl ketone, 50.9 g of potassium carbonate, and 2.6 g of potassium iodide were charged into a four-neck flask and substituted with nitrogen. The temperature was then raised to 90°C, and 51.6 g of methyl isobutyl ketone was distilled out under reduced pressure. The pressure was then returned to normal pressure with nitrogen, the introduction of nitrogen gas was stopped, and 53.4 g (0.44 mol) of ethyl chloroacetate, a halide to which 0.5 g of N-methylpyrrolidone had been added, was added dropwise over 2 hours while maintaining the temperature of the reaction solution at 80°C. After the dropwise addition was completed, nitrogen gas was introduced into the reaction system at a rate of 180 mL/min (1,031 mL/min per mole of 1,1'-binaphthalene-2,2'-diol (A)) while maintaining the temperature inside the flask at 80°C. Stirring was continued while discharging from the reaction system carbon dioxide gas generated as the reaction proceeded together with nitrogen gas, and the reaction was completed 10 hours after the dropwise addition was completed.
The results of HPLC analysis of the target aromatic bisether compound (B) and monoether (C) 4, 6, 8 and 10 hours after the completion of the dropwise addition are shown in Table 1.

<Comparative Example 1>
50.0 g (0.17 mol) of 1,1'-binaphthalene-2,2'-diol (A), an aromatic dihydroxy compound, 125.0 g of methyl isobutyl ketone, 50.7 g of potassium carbonate, and 1.0 g of potassium iodide were charged into a four-neck flask and substituted with nitrogen. Then, the temperature was raised to 90°C, and 50.6 g of methyl isobutyl ketone was distilled out under reduced pressure. Then, the pressure was returned to normal pressure under a nitrogen atmosphere, and 53.5 g (0.44 mol) of ethyl chloroacetate, a halide to which 0.5 g of N-methylpyrrolidone had been added, was added dropwise over 2 hours while maintaining the temperature of the reaction solution at 80°C. Then, without introducing nitrogen gas into the flask, stirring was continued under normal pressure while maintaining the temperature in the flask at 80°C, and the reaction was completed 22 hours after the end of the dropwise addition.
The results of HPLC analysis of the target aromatic bisether compound (B) and monoether (C) 4, 6, 12, 16, 20 and 22 hours after the completion of the dropwise addition are shown in Table 1.

Example 2
The reaction was carried out under the same conditions as in Example 1, except that the reaction temperature was 90° C. The reaction was completed 8 hours after the end of the dropwise addition.
The results of HPLC analysis of the target aromatic bisether compound (B) and monoether (C) 4, 6 and 8 hours after the completion of the dropwise addition are shown in Table 1.

<Comparative Example 2>
The reaction was carried out under the same conditions as in Example 2, except that nitrogen gas was not introduced into the flask. The reaction was completed 12 hours after the end of the dropwise addition.
The results of HPLC analysis of the target aromatic bisether compound (B) and monoether (C) 4, 8 and 12 hours after the completion of the dropwise addition are shown in Table 1.

As shown in Table 1, it was confirmed that, in Examples 1 and 2, which are specific examples of the present invention in which the reaction is carried out under the introduction of an inert gas, the reaction time for obtaining the target aromatic bisether compound was significantly shortened and the conversion of the aromatic monoether compound to the target compound was promoted, compared to Comparative Examples 1 and 2 in which no inert gas was introduced.
Specifically, when Example 2 and Comparative Example 2, in which the reaction conditions differ only in terms of whether or not an inert gas was introduced, were compared, it became clear that the reaction time could be shortened by approximately 40% judging from the remaining amount of aromatic monoether compound.

Claims (5)

A method for producing an aromatic bisether compound represented by the following formula (3), comprising reacting an aromatic dihydroxy compound (1) represented by the following formula (1), a halide (2) represented by the following formula (2), and an alkali metal carbonate or an alkali metal hydrogen carbonate while introducing an inert gas and discharging gas from within the reaction system.

In formula (1), Ar ₁ and Ar ₂ each independently represent a benzene ring or a naphthalene ring, R ₁ each independently represent a linear or branched alkyl group having 1 to 6 carbon atoms, a cyclic alkyl group having 5 to 6 carbon atoms, or an aryl group having 6 to 12 carbon atoms, n each independently represent an integer of 0 to 4, and X each independently represent a single bond or a divalent group represented by any one of the following formulas (1a) and (1b):

In formulae (1a) and (1b), R ₂ 's each independently represent hydrogen, a linear or branched alkyl group having 1 to 10 carbon atoms, a halogenated alkyl group having 1 to 10 carbon atoms, or an aryl group having 6 to 12 carbon atoms; R ₂ 's may be bonded to each other to form a cycloalkylidene group having 5 to 20 carbon atoms as a whole; Ar ₃ and Ar ₄ each independently represent a benzene ring or a naphthalene ring; and * indicates the bonding position with Ar ₁ or Ar ₂ , respectively.

In formula (2), Y represents a halogen atom, and A represents one group selected from a linear or branched alkyl group having 1 to 10 carbon atoms, a cyclic alkyl group having 1 to 10 carbon atoms, a glycidyl group, an aryl group having 6 to 12 carbon atoms, and a group represented by the following formula (2a) or the following formula (2b):

(In formula (2a), _R4 represents a linear or branched alkylene group having 1 to 4 carbon atoms, _R5 represents a linear or branched alkyl group having 1 to 10 carbon atoms or an alkenyl group having 2 to 10 carbon atoms, and * represents the bonding position with Y.)

(In formula (2b), _R6 represents a linear or branched alkyl group having 1 to 4 carbon atoms or a hydrogen atom, and * represents the bonding position with Y.)

(In formula (3), Ar ₁ , Ar ₂ , R ₁ , n, and X are the same as those in formula (1), and A is the same as that in formula (2).) The method for producing an aromatic bisether compound according to claim 1, wherein the inert gas is introduced at a flow rate of 20 to 120 L per hour per mole of the aromatic dihydroxy compound (1). The method for producing an aromatic bisether compound according to claim 1, wherein X in formula (1) and formula (3) is a single bond. The method for producing an aromatic bisether compound according to claim 1 or 2, wherein Ar ₁ and Ar ₂ in the formula (1) and the formula (3) are both naphthalene rings. The method for producing an aromatic bisether compound according to claim 3, wherein R ₅ in the formula (2a) is a linear or branched alkyl group having 1 to 10 carbon atoms.