JP2003238470A - Method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether and polymer using the ether as monomer - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether useful as a monomer producing selectively and simply polycarbonates having excellent abrasion and heat resistances. <P>SOLUTION: This method for producing the 4,4'-dihydroxy-3,3'- dimethyldiphenyl ether comprises formylating 4,4'-dihydroxy-diphenyl ether and then methylating the product, or by alkylating 4,4'-dihydroxy-diphenyl ether, formylating the product, and methylating and finally dealkylating the product. <P>COPYRIGHT: (C)2003,JPO

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, and more particularly, it is useful as a raw material monomer for a polymer material having excellent abrasion resistance and heat resistance. The present invention relates to a method for selectively and conveniently producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether.

[0002]

2. Description of the Related Art As diols which are raw materials for polymer compounds, bisphenol A, bisphenol S, hydroquinone, resorcin, 2,6-hydroxynaphthalene,
Aromatic diols such as 2,5-hydroxynaphthalene,
Aliphatic or alicyclic diols such as ethylene glycol, propylene glycol and cyclohexanedimethanol are also used. These are used as constituent components of resins such as polycarbonate, polyester, polyurethane and polyether.

As a typical aromatic polycarbonate resin, a polycarbonate resin obtained by reacting bisphenol A with phosgene or diphenyl carbonate is known as a representative one. Such polycarbonate resins have excellent properties in terms of transparency, heat resistance, dimensional accuracy, mechanical strength, etc., and are therefore used in many fields.

These polycarbonates, polyesters,
In order to improve the heat resistance, chemical resistance, and mechanical properties of resins such as polyurethane and polyether, it is known to introduce a constituent component having an ether bond in the molecule. For example, aromatic diols include 4,4'-dihydroxydiphenyl ether and 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether.

As a method for synthesizing a dihydroxydiphenyl ether compound, generally known is a method in which hydroquinone is heated together with hydrogen fluoride to directly synthesize 4,4'-dihydroxydiphenyl ether (US Pat. No. 2,73).
9,171 specification). In addition, JP-A-49-5563
No. 5 discloses a production method characterized in that hydroquinone is reacted in the presence of a natural or synthetic aluminum silicate in an inert solvent. 2-methylhydroquinone to dimethyldihydroxydiphenyl ether
It is reported that a mixture of isomers is obtained.

To selectively synthesize only 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether among the above-mentioned three isomers, p-alkoxyphenol and a halide are hydrated with an alkali metal. There is known a method in which Ullmann reaction is carried out in the presence of a compound or a carbonate and copper or a copper compound to give a dialkoxydiphenyl ether compound, which is then dealkylated.

Thus, 4,4'-dihydroxy-3,
3'-Dimethyldiphenyl ether is synthesized, but 2
In the method of producing from methylhydroquinone, as described above, it is obtained as a mixture of several isomers, and it is necessary to purify it, which is a problem. Further, in the method involving the Ullmann reaction between p-alkoxyphenol and a halide, the Ullmann reaction is carried out at a high temperature, so that a side reaction easily occurs and subsequent purification is not easy and is a problem.
There is also a problem that the synthetic route is long and not efficient.

[0008]

SUMMARY OF THE INVENTION The present invention has been made in view of the above problems of the prior art, and is useful as a raw material monomer for a polymer material such as a polycarbonate resin having excellent abrasion resistance and heat resistance. Na 4,4'-dihydroxy-
An object of the present invention is to provide a method for producing 3,3′-dimethyldiphenyl ether, which does not produce an isomer as in the prior art, can always selectively synthesize only one kind of target compound, and can be simply produced.

[0009]

Means for Solving the Problems As a result of intensive studies made by the present inventors, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether can be selectively and conveniently produced directly from 4,4'-dihydroxydiphenyl ether. The inventors have found a method of doing so and arrived at the present invention. That is, according to the present invention, firstly, in claim 1, 4,4'-dihydroxy-diphenyl ether is formylated, and then methylated, which is 4,4'-dihydroxy-3,3'-. A method for producing dimethyldiphenyl ether is provided.

Secondly, in claim 2, 4,4'-dihydroxy-diphenyl ether is alkylated, then formylated and methylated in that order, and finally dealkylated. -Dihydroxy-3,
A method for producing 3'-dimethyldiphenyl ether is provided.

Thirdly, in the third aspect of the present invention, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to the first or second aspect, the formylation reaction is carried out with dichloromethyl methyl ether. 4,4'-dihydroxy-characterized by using titanium chloride
A method for producing 3,3′-dimethyldiphenyl ether is provided.

Fourthly, in claim 4, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to claim 1 or 2, alkali metal hydroxide is used in the formylation reaction. 4,4'-dihydroxy-, characterized by using chloroform in the presence of
A method for producing 3,3′-dimethyldiphenyl ether is provided.

Fifthly, in the fifth aspect, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to the first or second aspect, the alkali metal hydroxide is used for the methylation reaction. 4,4'-dihydroxy-3, characterized by using hydrazine in the presence of
A method for producing 3'-dimethyldiphenyl ether is provided.

Sixthly, in claim 6, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to claim 1 or 2, dichloromethyl methyl ether and titanium tetrachloride are used. Or 4, a formylation reaction is performed using chloroform in the presence of an alkali metal hydroxide, and then a methylation reaction is performed using hydrazine in the presence of an alkali metal hydroxide 4,4 A method for producing'-dihydroxy-3,3'-dimethyldiphenyl ether is provided.

Seventh, in the seventh aspect, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to the second aspect, methyl iodide is used in the alkylation reaction. A method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether is provided.

Eighth, in the eighth aspect, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to the second aspect, boron trihalide is used in the demethylation reaction. Characteristic 4,4'-
A method for producing dihydroxy-3,3'-dimethyldiphenyl ether is provided.

Ninth, according to a ninth aspect, in the method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether according to the eighth aspect, the boron trihalide is boron tribromide. Provided is a method for producing 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, which is characterized.

Tenth, a tenth aspect of the present invention is the 4,4'-dihydroxy- group according to any one of the first to ninth aspects.
Using 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether produced by the method for producing 3,3′-dimethyldiphenyl ether as a raw material monomer,
A polymer compound obtained by polymerization is provided.

[0019]

BEST MODE FOR CARRYING OUT THE INVENTION The present invention is described in detail below.
The present invention is a method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether by introducing a methyl group at the 3-position from 4,4′-dihydroxydiphenyl ether. The method of introducing a methyl group is a method of first performing formylation and then performing reductive methylation.

As the formylation reaction, a known formylation reaction can be used, but the raw material 4,4 '
Attention must be paid to the reactivity of the dihydroxydiphenyl ether. For example, formylation with Vilsmeier reagent is less reactive, in which case almost no formylation occurs.

Therefore, a preferable example of the formylation reaction is to react dichloromethyl methyl ether in the presence of titanium tetrachloride. Usually, dichloromethyl methyl ether is used in an amount of 2.0 to 3.0 times equivalent to 4,4′-dihydroxydiphenyl ether, and titanium tetrachloride is used in an amount of 2.0 to 5.0 times equivalent. A minimum of equimolar reagents is required for single-site formylation. Dichloromethane and diethyl ether are used as the reaction solvent, and dichloromethane is preferable. The reaction temperature is
It is carried out at -50 ° C to 20 ° C. It is more preferable to perform the reaction at a low temperature of −40 ° C. to 0 ° C., because the reaction is violent. The reaction time is preferably 0.5 to 5 hours.

As another method of formylation, it can be synthesized by reacting chloroform in the presence of an alkali metal hydroxide (Reimer-Tiemann reaction).
As the alkali metal hydroxide, hydroxides of alkali metals such as sodium, potassium and lithium can be used, but sodium hydroxide is particularly preferably used because of its high reactivity. The reaction temperature is preferably 20 ° C to 90 ° C, and the reaction time is preferably 0.5 to 10 hours.

The methylation reaction may be any reaction that reductively methylates an aldehyde. Above all, a method of reacting hydrazine in the presence of an alkali metal hydroxide is conveniently used. As the alkali metal hydroxide, hydroxides of alkali metals such as sodium, potassium and lithium can be used, but potassium hydroxide is particularly preferably used because of its high reactivity. As the reaction solvent, those having a high boiling point such as ethylene glycol and diethylene glycol are used. The reaction temperature is 110 ° C to 190 ° C.
Done in. More preferably, it is 130 ° C to 170 ° C. The reaction time is preferably 0.5 to 10 hours.

By the above two-step reaction, 4,4'-dihydroxydiphenyl ether can be selectively and conveniently converted into 4,4'-dihydroxydiphenyl ether.
4'-dihydroxy-3,3'-dimethyldiphenyl ether can be synthesized. Since the yield of each reaction is good in this production method, the target compound can be obtained in high yield. Further, it can also be produced by alkylating 4,4′-dihydroxydiphenyl ether, protecting the hydroxy group, formylating and methylating, and finally dealkylating. Although the number of synthetic routes is increased, side reactions are further suppressed and a highly pure compound can be obtained.

As the above-mentioned alkylation reaction, for example, there is a method in which 4,4'-dihydroxydiphenyl ether is reacted with methyl iodide in acetone in the presence of sodium hydroxide. In addition to this, a known reaction can be used to carry out alkylation, preferably methylation, to protect the hydroxy group.

As the dealkylation reaction, all conventionally known reactions can be used, and specific examples thereof include a method using an acidic reagent and a method using a basic reagent. As the acidic reagent, hydrogen bromide, hydrogen iodide, trifluoroacetic acid, pyridine hydrochloride, concentrated hydrochloric acid, magnesium iodide ethylate, aluminum chloride, aluminum bromide, boron trihalide,
Boron tribromide is preferable. As the basic reagent, potassium hydroxide, sodium hydroxide, sodium, lithium, sodium iodide, lithium iodide,
Examples thereof include lithium diphenylphosphide and sodium thioethylate. Acetic anhydride as a solvent,
Dichloromethane, tetrahydrofuran (THF), N,
N-dimethylformamide (DMF), pyridine, butanol and the like can be mentioned. The reaction temperature depends on the reactivity of the reagent to be used, but it is generally from -10 ° C to 200 ° C.

Up to now, it has been synthesized through Ullmann reaction and demethylation of 4-bromo-2-methylanisole and 4-methoxy-3-methylphenol. However, 4-bromo-2-methylanisole and 4-methoxy-3-methylphenol, which are the raw materials, also had to be synthesized from the previous stage, the synthetic route was long, and the starting material reagents were expensive. Moreover, the Ullmann reaction was carried out at high temperature, and there were many side reactions, and purification was not easy. In the present invention, it is inexpensive 4,
4,4'-Dihydroxy-3,3'-dimethyldiphenyl ether can be easily synthesized from 4'-dihydroxydiphenyl ether. This can solve all the problems in the past and is far superior to the conventional method.

As described above, 4,4'-dihydroxy-
3,3′-Dimethyldiphenyl ether is synthesized, and this compound is also useful as an intermediate for producing various materials derived from a hydroxyl group, for example, a polycarbonate resin, a polyester resin, a polyurethane resin, an epoxy resin or the like. .

In the case of synthesizing an organic polymer compound from 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether, it can be produced by a conventionally known method for synthesizing a condensation polymer, mainly polycondensation or polyaddition. Can be manufactured by. These methods are described in, for example, “New Polymer Experiments 3 Polymer Synthesis / Reaction (2) Condensation Polymer Synthesis, Kyoritsu Shuppan Co., Ltd.”, Polymer Society of Japan.

The 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether and the polymer compounds derived therefrom produced by the present invention have a wide range of applications and are used for various purposes. As an example, the monomer has an antioxidant and a color developer for thermal recording paper, and the polymer has an ether skeleton and a methyl group at the 3-position in its basic skeleton, and therefore has excellent wear resistance and heat resistance. is doing. Utilizing this property, it can be applied to a binder resin for an optical disk substrate, an organic photoreceptor used in an electrophotographic method, a copolymer species for a polymer type charge transport material, and the like.

[0031]

EXAMPLES Next, the present invention will be described in more detail by way of examples. However, the present invention is not limited to the following examples. In the examples, all parts are parts by weight.

Example 1 (Alkylation) 20 parts of 4,4'-dihydroxydiphenyl ether, 8.8 parts of sodium hydroxide and 200 parts of acetone were placed in a stirring reaction vessel and stirred and refluxed for 75 minutes. Methyl iodide (53 parts) was added thereto, and the mixture was further refluxed for 3 hours. After the reaction, the mixture was cooled and poured into 600 parts of water. Crystals precipitated and were filtered and washed with water three times. Almost quantitatively, 4,4'-dimethoxydiphenyl ether was obtained. Melting point is 10
It was 0.5 to 101.5 ° C, which was in agreement with the literature value.

Example 2 (formylation) 4,4'-dimethoxydiphenyl ether (20 parts) and dehydrated dichloromethane (250 parts) were placed in a stirred reaction vessel and the temperature was adjusted to -40 ° C under a nitrogen stream. Titanium tetrachloride 65 with cooling
Parts, and then dichloromethyl methyl ether 23
Parts were dropped. After dropping, the mixture was reacted at -40 ° C for 2.5 hours. After the reaction, the mixture was poured into ice water and stirred for 30 minutes at room temperature. The organic layer was washed with water, a 5% aqueous sodium hydrogencarbonate solution and water in this order, and finally dried over anhydrous magnesium sulfate. The filtrate was concentrated, purified by recrystallization with toluene / ethyl acetate,
19 parts of a diformyl body was obtained.

Example 3 (Methylation) 19 parts of diformyl body, 13 parts of hydrazine monohydrate, 17 parts of potassium hydroxide and 250 parts of diethylene glycol were placed in a stirring reaction vessel and reacted at 150 ° C. for 5 hours. After the reaction, the mixture was cooled and poured into ice water. It was extracted with toluene, the organic layer was washed with water three times, and finally dried over anhydrous magnesium sulfate. The filtrate was concentrated, and column chromatography with silica gel was performed using a toluene / normal hexane (1/1) mixed solvent to obtain 11 parts of 4,4′-dimethoxy-3,3′-dimethyldiphenyl ether.

Example 4 (Dealkylation) 11 parts of 4,4'-dimethoxy-3,3'-dimethyldiphenyl ether thus obtained were dissolved in 70 parts of dichloromethane and placed in a stirred reaction vessel at -5 ° C. under a nitrogen stream. A solution prepared by dissolving 20 parts of boron tribromide in 10 parts of dichloromethane was prepared as 1
It dripped slowly over 5 minutes. After the dropping, the temperature was gradually returned to room temperature and the reaction was performed for 2 hours. After the reaction, the reaction solution was poured into 500 parts of ice water and stirred for 30. The organic layer was washed with water, a 5% aqueous sodium hydrogencarbonate solution and water in this order, and finally dried over anhydrous magnesium sulfate. The filtrate was concentrated and subjected to column chromatography on silica gel with toluene / ethyl acetate (4 /
1) A mixed solvent was used, and recrystallization and purification were performed with toluene to obtain 7 parts of 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether. The melting point of this compound is 1
At 41.0 to 142.0 ° C., the elemental analysis results are as follows, which are in agreement with the values calculated from the structural formula.

Comparative Example (Manufacturing Method via Ullmann Reaction) 92 parts of o-anisole, 147 parts of NBS (N-bromosuccinimide) and 270 parts of dehydrated acetonitrile were placed in a stirring reaction vessel and reacted at room temperature for 2 hours. After the reaction, carbon tetrachloride was added and succinimide was filtered. The filtrate was concentrated and subjected to column chromatography with silica gel using a cyclohexane solvent to obtain 125 parts of 4-bromo-2-methylanisole.

3-Methyl-p-anisaldehyde 6.4
Parts, m-chloroperbenzoic acid 13 parts, dichloromethane 20
0 part was placed in a stirred reaction vessel and refluxed for 11 hours under a nitrogen stream. After the reaction, the mixture was cooled, ethyl acetate was added, and the organic layer was washed 5 times with a 5% aqueous sodium hydrogen carbonate solution and once with a saturated saline solution. Finally dried over anhydrous magnesium sulfate,
The filtrate was concentrated. 25 parts of methanol and 20 parts of 10% aqueous potassium hydroxide solution were added to the filtrate, and the mixture was reacted at room temperature for 2 hours under a nitrogen stream. After the reaction, 50 parts of ethyl acetate was added for extraction. The organic layer was concentrated and subjected to column chromatography with silica gel using a toluene solvent to give 4-methoxy-3.
4 parts of methylphenol are obtained.

4-Bromo-2-methylanisole 28
Part, 4-methoxy-3-methylphenol, 29 parts, potassium hydroxide, 13 parts, and activated copper, 9 parts were placed in a stirring reaction vessel and reacted at 220 ° C. for 3 hours under a nitrogen stream. After the reaction, the mixture was cooled, toluene was added, and the mixture was filtered through Celite. The filtrate was concentrated and column chromatography with silica gel was performed with toluene /
It carried out twice using a normal hexane (1/1) mixed solvent to obtain 21 parts of 4,4′-dimethoxy-3,3′-dimethyldiphenyl ether. The 4,4'-dimethoxy-3,3'-dimethyldiphenyl ether thus obtained was treated in the same manner as in Example 4 above to give 4,4'-dihydroxy-3,
3'-Dimethyldiphenyl ether was obtained. Melting point is 14
At 1.5 to 142.5 ° C., the result of elemental analysis is as follows, which is in agreement with the value calculated from the structural formula.

As described above, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether produced according to the examples is easy to handle in each reaction, has a good yield, and can be easily synthesized. On the other hand, although it can be produced by the production method of Comparative Example, some reactions have a long reaction time, and a side reaction occurs in the Ullmann reaction, which makes purification difficult. Therefore, when comprehensively judged, the synthetic route of the example is excellent.

[0040]

As described above, according to the production method of claim 1, 4,4′-dihydroxy-diphenyl ether is formylated and then methylated, so that it can be selectively and conveniently carried out by a two-step reaction. From 4,4'-dihydroxydiphenyl ether to 4,4'-dihydroxy-3,
3'-Dimethyldiphenyl ether can be synthesized. Furthermore, since the yield of each reaction is good, the target compound can be obtained in high yield.

According to the manufacturing method of claim 2, 4,4'-
Since alkylation of dihydroxy-diphenyl ether, followed by formylation and methylation and finally dealkylation, the hydroxy group is protected by alkylation, followed by formylation and methylation, and finally dealkylation. Although the number of synthetic routes is increased, side reactions are further suppressed and a highly pure compound can be obtained.

According to the production method of claim 3, in the production method of claim 1 or 2, since dichloromethyl methyl ether and titanium tetrachloride are used in the formylation reaction, the reactivity is excellent and the formylation is performed. It can be easily performed at low temperature and in a short period of time.

According to the production method of claim 4, in the production method of claim 1 or 2, chloroform is used in the presence of an alkali metal hydroxide in the formylation reaction. The reaction can be easily carried out at low temperature and in a short time.

According to the production method of claim 5, since hydrazine is used in the presence of an alkali metal hydroxide in the methylation reaction in the production method of the above-mentioned claim 1 or 2, the methylation reaction can be carried out easily. It can be performed.

According to the manufacturing method of claim 6, in the manufacturing method of claim 1 or 2, dichloromethyl methyl ether and titanium tetrachloride are used, or chloroform is used in the presence of an alkali metal hydroxide. Formylation reaction is carried out, and then the methylation reaction is carried out using hydrazine in the presence of an alkali metal hydroxide. Therefore, the formylation reaction can be carried out easily at low temperature and in a short time, and the methylation reaction can be carried out. It can be done easily.

According to the manufacturing method of claim 7, in the manufacturing method of claim 2, since methyl iodide is used in the alkylation reaction, methylation can be easily carried out and the hydroxy group can be protected. it can.

According to the manufacturing method of claim 8, in the manufacturing method of claim 2, since boron trihalide is used in the demethylation reaction, demethylation with an acidic reagent can be easily carried out.

According to the manufacturing method of the ninth aspect, in the manufacturing method of the eighth aspect, since the boron trihalide is boron tribromide, demethylation with an acidic reagent can be easily and preferably performed.

According to the polymer compound of claim 10, 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether produced by the production method according to any one of claims 1 to 9 is used as a raw material monomer. Therefore, a polymer material having excellent wear resistance and heat resistance can be obtained economically and easily. These materials are widely used for optical disk substrates, organic photoconductors and the like as useful polycarbonate resins, polyester resins and the like.

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Kazuyoshi Nagai             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh (72) Inventor Lee Honggu             1-3-3 Nakamagome, Ota-ku, Tokyo Stocks             Company Ricoh F term (reference) 4H006 AA02 AA03 AC11 AC23 AC41                       AC43 BA10 BB11 BB14 BB16                       BB17 BC10 BC19 BC31 BC34                       BE10 BE27 GP06 GP12                 4H039 CA62 CD10

Claims (10)

[Claims] 1. A method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, which comprises formylating 4,4′-dihydroxy-diphenyl ether and then methylating it. 2. A 4,4′-dihydroxy-3,3 ′ which is characterized in that 4,4′-dihydroxy-diphenyl ether is alkylated, then formylated and methylated in that order, and finally dealkylated. -Method for producing dimethyldiphenyl ether. 3. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 1 or 2, wherein dichloromethyl methyl ether and titanium tetrachloride are used in the formylation reaction. 4,4'-dihydroxy-3,3'-dimethyldiphenyl ether. 4. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 1, wherein chloroform is used in the formylation reaction in the presence of an alkali metal hydroxide. A method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, characterized in that 5. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 1, wherein hydrazine is used in the methylation reaction in the presence of an alkali metal hydroxide. A method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether, characterized in that 6. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 1 or 2, wherein dichloromethyl methyl ether and titanium tetrachloride are used, or an alkali metal hydroxide. Formylation reaction using chloroform in the presence of
Then, methylation reaction is carried out using hydrazine in the presence of an alkali metal hydroxide 4,4′-
A method for producing dihydroxy-3,3'-dimethyldiphenyl ether. 7. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 2, wherein methyl iodide is used in the alkylation reaction. A method for producing 3,3′-dimethyldiphenyl ether. 8. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 2, wherein boron trihalide is used in the demethylation reaction. Dihydroxy-3,3'-
Method for producing dimethyl diphenyl ether. 9. The method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to claim 8, wherein the boron trihalide is boron tribromide. A method for producing dihydroxy-3,3'-dimethyldiphenyl ether. 10. A 4,4′-produced by the method for producing 4,4′-dihydroxy-3,3′-dimethyldiphenyl ether according to any one of claims 1 to 9.
A polymer compound obtained by polymerization using dihydroxy-3,3′-dimethyldiphenyl ether as a raw material monomer.