JP2023077682A - 2,6-dimethylphenol and polyphenylene ether - Google Patents

Abstract

To provide: 2,6-dimethylphenol derived from a renewable raw material which, while having a low environmental load and being sustainable, has the same level of polymerization activity as a fossil resource-derived 2,6-dimethylphenol; and polyphenylene ether which is an oxidation polymer of the same.SOLUTION: The 2,6-dimethylphenol of the present invention is one obtained by a reaction of phenol and methanol, where at least one of phenol and methanol includes a renewable raw material. Further, the polyphenylene ether of the present invention is characterized in that it is one obtained by oxidative polymerization of 2,6-dimethylphenol synthesized from a renewable raw material.SELECTED DRAWING: None

Description

The present invention relates to 2,6-dimethylphenol and polyphenylene ethers.

In recent years, environmental issues have come to be emphasized, and regulations on carbon dioxide emissions have been tightened. Attention is focused on the use of raw materials. For this reason, polyphenylene ether, which is an engineering plastic, is also desired to use a phenol derivative, which is a renewable raw material, as a structural unit.

As described in Patent Document 1, phenol derivatives, which are renewable raw materials, have long-chain hydrocarbon groups unlike unsubstituted phenol, so when incorporated as a structural unit of a polyphenylene ether skeleton, there is a concern that heat resistance may decrease. be done. Therefore, 2,6-dimethylphenol, which is a typical repeating unit of commercially produced polyphenylene ether, is produced from unsubstituted phenol derived from renewable resources and methanol derived from renewable resources to obtain polyphenylene ether. It is desired to be utilized as a raw material for phenol.

Japanese Patent Publication No. 2000-509097

The present invention has been made in view of the above problems, and is synthesized from renewable raw materials that has a polymerization activity equivalent to 2,6-dimethylphenol derived from fossil resources while having a low environmental load and sustainability. An object of the present invention is to provide 2,6-dimethylphenol. Another object of the present invention is to provide a polyphenylene ether with low environmental load and sustainability, which is obtained by oxidative polymerization using 2,6-dimethylphenol derived from renewable raw materials as a raw material.

That is, the present invention is as follows.
[1]
2,6-dimethylphenol obtained by the reaction of phenol and methanol, characterized in that at least one of said phenol and said methanol comprises a renewable raw material.
[2]
The 2,6-dimethylphenol according to [1], wherein the renewable raw material phenol is biomass-derived and/or the renewable raw material methanol is biomass-derived.
[3]
2,6-dimethylphenol according to [1], wherein the renewable raw material methanol is derived from carbon dioxide.
[4]
A polyphenylene ether obtained by the oxidation polymerization reaction of 2,6-dimethylphenol according to any one of [1] to [3].

According to the present invention, 2,6-dimethylphenol synthesized from renewable raw materials has a low environmental load and is sustainable, while having polymerization activity equivalent to 2,6-dimethylphenol derived from conventional fossil resources. Furthermore, it is possible to obtain a polyphenylene ether with low environmental load and sustainability by performing oxidative polymerization using 2,6-dimethylphenol derived from renewable raw materials as a raw material.

EMBODIMENT OF THE INVENTION Hereinafter, the form (henceforth "this embodiment") for implementing this invention is demonstrated in detail. The following embodiments are exemplifications for explaining the present invention, and the present invention is not limited only to these embodiments, and the present invention can be appropriately modified within the scope of the gist thereof. can be implemented.
In this specification, A (numerical value) to B (numerical value) mean A or more and B or less.

<2,6-dimethylphenol>
2,6-Dimethylphenol according to the present embodiment can be obtained by including renewable raw materials in at least one of phenol and methanol, which are raw materials for its synthesis.
In the present disclosure, a renewable raw material means a raw material that has a reduced carbon dioxide emission throughout its life cycle, from raw material procurement to disposal, compared to raw materials derived from fossil resources.

The content of phenol, which is a renewable raw material among phenol as a raw material for synthesis, is preferably 60% by mass or more, more preferably 80% by mass or more, and most Preferably it is 100% by mass.
In addition, the content of methanol, which is a renewable raw material in the synthetic raw material methanol, is preferably 60% by mass or more, more preferably 80% by mass or more, in order to increase the biomass component rate from the viewpoint of being environmentally friendly. , most preferably 100% by weight.

The 2,6-dimethylphenol may be synthesized by a reaction between methanol containing methanol as a renewable raw material and phenol derived from petrochemicals, or a reaction between methanol derived from petrochemicals and phenol containing phenol as a renewable raw material. or by reacting methanol containing methanol as a renewable raw material with phenol containing phenol as a renewable raw material. In order to increase the biomass content rate from the viewpoint of being environmentally friendly, 2,6-dimethylphenol is obtained by reacting methanol containing methanol as a renewable raw material with phenol containing phenol as a renewable raw material. is more preferred, and it is particularly preferred that it is obtained by reacting only methanol as a renewable raw material and only phenol as a renewable raw material.

<Method for producing 2,6-dimethylphenol>
As the method for producing 2,6-dimethylphenol according to the present embodiment, a known production method used for synthesizing conventional 2,6-dimethylphenol derived from fossil resources may be applied. Specifically, a production method in which phenol and optionally ortho-cresol are brought into contact with methanol in a gas phase, and as described in JP-B-2-33693, a metal oxide supported on silica is used as a catalyst. Examples include a production method in which the reaction is performed in a fluidized bed.

<Methanol, a renewable raw material>
Specific examples of the renewable raw material methanol according to the present embodiment include those produced from biological resources (biomass) derived from animals and plants, those produced from carbon dioxide, and the like. Products manufactured from biomass also include products manufactured according to a mass balance approach and certified by certification bodies such as ISCC, REDcert. Examples of biomass include solid components such as cattle and pig manure, plants, paper waste, etc., and by-products (glycerin) during biodiesel production, which are obtained from plant-derived oils and fats such as palm oil and sunflower oil. is mentioned.

Methanol, which is a renewable raw material according to the present embodiment, is more specifically produced by producing biomass gas by a thermochemical method from biological resources derived from animals and plants, and reacting it with a catalyst to produce methanol (Japanese Patent Application Laid-Open 2010-6710), and a method of producing from synthesis gas containing hydrogen, carbon monoxide and carbon dioxide (International Publication No. 2017/175760).

<Renewable raw material phenol>
Phenol, which is a renewable raw material according to the present embodiment, specifically includes those produced from biological resources (biomass) derived from animals and plants, those produced from carbon dioxide, and the like. Products manufactured from biomass also include products manufactured according to a mass balance approach and certified by certification bodies such as ISCC, REDcert. Examples of biomass include woody biomass (lignin, etc.), mixed sugar extracted from plant resources, and the like.

More specifically, phenol, which is a renewable raw material according to the present embodiment, is obtained by adding a hydrogenation catalyst to a biomass solution or slurry liquid containing lignin contained in wood as a main component, and causing a hydrogenation reaction under high pressure and high temperature. , A method of obtaining phenol without substituents from lignin components (Japanese Patent Application Laid-Open No. 2018-62492), a method of producing phenol from sugars using microorganisms (International Publication No. 2012/033112), etc. Can be obtained. is.

<Polyphenylene ether>

The polyphenylene ether according to this embodiment is a homopolymer and/or copolymer obtained by oxidative polymerization of 2,6-dimethylphenol of this embodiment obtained from the renewable raw material described above.

式（１）中、Ｒ_１、Ｒ_２、Ｒ_３、及びＲ_４は、それぞれ独立して、水素原子、ハロゲン原子、炭素数１～７のアルキル基、フェニル基、炭化水素オキシ基、少なくとも２個の炭素原子がハロゲン原子と酸素原子とを隔てているハロ炭化水素オキシ基からなる群から選択される。 When the polyphenylene ether according to the present embodiment is a copolymer, for example, it may be obtained by copolymerizing a phenol compound derived from fossil raw materials and/or renewable raw materials represented by the following formula (1).

In formula (1), R ₁ , R ₂ , R ₃ and R ₄ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a phenyl group, a hydrocarbonoxy group, at least 2 is selected from the group consisting of halohydrocarbonoxy groups in which one carbon atom separates the halogen atom from the oxygen atom;

In formula (1), the halogen atoms represented by R ₁ , R ₂ , R ₃ and R ₄ include fluorine, chlorine and bromine atoms, preferably chlorine and bromine atoms.

In the above formula (1), the alkyl group having 1 to 7 carbon atoms represented by R ₁ , R ₂ , R ₃ and R ₄ is a linear or branched alkyl group having 1 to 7 carbon atoms. and preferably having 1 to 6 carbon atoms, more preferably 1 to 3 carbon atoms, such as methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl, tert-butyl, pentyl, hexyl and the like. , methyl and ethyl are preferred, and methyl is more preferred.
In formula (1), the C 1-7 alkyl groups represented by R ₁ , R ₂ , R ₃ and R ₄ may be substituted with one or more substituents at substitutable positions. good.
Such substituents include halogen atoms (e.g., fluorine atom, chlorine atom, bromine atom, etc.), alkyl groups having 1 to 6 carbon atoms (e.g., methyl, ethyl, propyl, isopropyl, butyl, isobutyl, sec-butyl , tert-butyl, pentyl, hexyl, etc.), aryl groups (e.g., phenyl, naphthyl, etc.), alkenyl groups (e.g., ethenyl, 1-propenyl, 2-propenyl, etc.), alkynyl groups (e.g., ethynyl, 1-propynyl, 2-propynyl, etc.), aralkyl groups (eg, benzyl, phenethyl, etc.), alkoxy groups (eg, methoxy, ethoxy, etc.), amino groups and the like.

In the polyphenylene ether of the present embodiment, specific phenol compounds represented by the formula (1) include, for example, o-cresol, 2,6-dimethylphenol, 2-ethylphenol, 2-methyl-6- Ethylphenol, 2,6-diethylphenol, 2-n-propylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl- 6-isopropylphenol, 2-methyl-6-n-propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl- 6-chlorophenol, 2-methyl-6-phenylphenol, 2-phenylphenol, 2,6-diphenylphenol, 2,6-bis-(4-fluorophenyl)phenol, 2-methyl-6-tolylphenol, 2 ,6-ditolylphenol, 2,5-dimethylphenol, 2,3,6-trimethylphenol, 2,5-diethylphenol, 2-methyl-5-ethylphenol, 2-ethyl-5-methylphenol, 2- Allyl-5-methylphenol, 2,5-diallylphenol, 2,3-diethyl-6-n-propylphenol, 2-methyl-5-chlorophenol, 2-methyl-5-bromophenol, 2-methyl-5 -isopropylphenol, 2-methyl-5-n-propylphenol, 2-ethyl-5-bromophenol, 2-methyl-5-n-butylphenol, 2,5-di-n-propylphenol, 2-ethyl-5 -chlorophenol, 2-methyl-5-phenylphenol, 2,5-diphenylphenol, 2,5-bis-(4-fluorophenyl)phenol, 2-methyl-5-tolylphenol, 2,5-ditolylphenol , 2,6-dimethyl-3-allylphenol, 2,3,6-triallylphenol, 2,3,6-tributylphenol, 2,6-di-n-butyl-3-methylphenol, 2,6- di-t-butyl-3-methylphenol, 2,6-dimethyl-3-n-butylphenol, 2,6-dimethyl-3-t-butylphenol and the like.

Among the phenol compounds represented by the formula (1), 2,6-dimethylphenol, 2,6-diethylphenol, 2,6-dimethylphenol, 2,6-diethylphenol, and 2,6- Diphenylphenol, 2,3,6-trimethylphenol and 2,5-dimethylphenol are preferred, and 2,6-dimethylphenol and 2,3,6-trimethylphenol derived from fossil raw materials are more preferred.

The phenol compounds represented by the formula (1) may be used singly or in combination of two or more.
For example, as the phenol compound represented by the formula (1), a method of using a combination of 2,6-dimethylphenol and 2,6-diethylphenol, a method of using 2,6-dimethylphenol and 2,6-diphenylphenol, and , a method of using 2,3,6-trimethylphenol and 2,5-dimethylphenol in combination, and a method of using 2,6-dimethylphenol and 2,3,6-trimethylphenol in combination. etc. At this time, the mixing ratio can be arbitrarily selected. In addition, the phenol compounds used include a small amount of m-cresol, p-cresol, 2,4-dimethylphenol, 2,4,6-trimethylphenol, etc., which are contained as by-products during manufacturing. may

The reduced viscosity of the polyphenylene ether of the present embodiment (0.5 dL/g chloroform solution, measured at 30° C.) is preferably in the range of 0.05 to 1.0 dL/g. The range of 0.05 to 0.30 dL/g is more preferable for applications that require solvent solubility and fluidity when melted, and 0.30 to 1 for applications that require excellent mechanical properties. A range of .0 dL/g is more preferred.

The method for controlling the reduced viscosity is not particularly limited, but for example, it can be adjusted by adjusting the polymerization time and the monomer addition time when producing the polyphenylene ether raw material. Moreover, when polymerization is carried out by a slurry polymerization method, it is possible to control the reduced viscosity to be small by increasing the proportion of a solvent having a higher poor solvent property.

In the present embodiment, in addition to the phenol compound represented by the above formula (1), two of the compounds used are fossil raw materials and / or renewable raw materials represented by the following formula (2). A phenolic compound may also be included.
A dihydric phenol compound as represented by the following formula (2) includes a corresponding monohydric phenol compound, aldehydes (e.g., formaldehyde), ketones (e.g., acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone , cyclohexanone, etc.), a reaction with a dihalogenated aliphatic hydrocarbon, or a reaction between the corresponding monohydric phenol compounds.

In formula (2), R ₅ , R ₆ , R ₇ and R ₈ each independently represent a hydrogen atom, a halogen atom, an alkyl group having 1 to 7 carbon atoms, a phenyl group, a haloalkyl group, an aminoalkyl group, is selected from the group consisting of hydrocarbonoxy groups and halohydrocarbonoxy groups in which at least two carbon atoms separate the halogen and oxygen atoms;
In formula (2), X is selected from the group consisting of a single bond, a divalent heteroatom, and a divalent hydrocarbon group having 1 to 12 carbon atoms.

Specifically, the dihydric phenol compound represented by the formula (2) includes, for example, compounds represented by the following general formulas (2-a), (2-b), and (2-c) is mentioned.

In formulas (2-a), (2-b), and (2-c), R ₅ , R ₆ , R ₇ , and R ₈ each independently represent a hydrogen atom, a halogen atom, and 1 carbon atom. selected from the group consisting of -7 alkyl groups, phenyl groups, haloalkyl groups, aminoalkyl groups, hydrocarbonoxy groups, and halohydrocarbonoxy groups in which at least two carbon atoms separate the halogen and oxygen atoms; be.
In formula (2-a), formula (2-b), and formula (2-c), X is a group consisting of a single bond, a divalent heteroatom, and a divalent hydrocarbon group having 1 to 12 carbon atoms. is selected from

Typical compounds represented by formulas (2-a), (2-b), and (2-c) include methyl groups for R ₅ and R ₆ and hydrogen atoms for R ₇ and R ₈ . in which X directly connects both aryl groups; a compound in which R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen atoms, and X is a methylene group; R ₅ and R ₆ are methyl a compound in which R ₇ and R ₈ are hydrogen atoms and X is a thio group; a compound in which R ₅ , R ₆ and R ₇ are a methyl group, R ₈ is a hydrogen atom and X is an ethylene group; R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen atoms, and X is an isopropylidene group; R ₅ and R ₆ are methyl groups, R ₇ and R ₈ are hydrogen atoms, and X is a compound that is a cyclohexylidene group; a compound in which R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is a hydrogen atom, and X directly connects both aryl groups; R ₅ , R ₆ and R ₇ are compounds in which R ₈ is a hydrogen atom and X is a methylene group; compounds in which R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is a hydrogen atom and X is an ethylene group; R ₅ , a compound in which R ₆ and R ₇ are methyl groups, R ₈ is a hydrogen atom, and X is a thio group; R ₅ , R ₆ and R ₇ are methyl groups, R ₈ is a hydrogen atom, and X is isopropylidene; a compound; a compound in which R ₅ , R ₆ , R ₇ and R ₈ are methyl groups and X is a methylene group; a compound in which R ₅ , R ₆ , R ₇ and R ₈ are methyl groups and X is an ethylene group compounds in which R ₅ , R ₆ , R ₇ and R ₈ are methyl groups and X is an isopropylidene group; and the like, but are not limited thereto.

Furthermore, in the present embodiment, the raw material may contain a polyhydric phenol compound derived from a fossil raw material and/or a renewable raw material, in addition to the phenol compound represented by the formula (1).
Examples of polyhydric phenol compounds include compounds having 3 or more but less than 9 phenolic hydroxyl groups in the molecule and having alkyl groups or alkylene groups at the 2- and 6-positions of at least one of the phenolic hydroxyl groups. is mentioned.

Examples of polyhydric phenol compounds are listed below. 4,4′-[(3-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(3-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4′-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4′-[(2-hydroxy-3-methoxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(4-hydroxy-3-ethoxyphenyl)methylene]bis(2, 3,6-trimethylethylphenol), 4,4′-[(3,4-dihydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(3,4-dihydroxyphenyl)methylene ] bis(2,3,6-trimethylphenol), 2,2′-[(4-hydroxyphenyl)methylene]bis(3,5,6-trimethylphenol), 4,4′-[4-(4- Hydroxyphenyl)cyclohexylidene]bis(2,6-dimethylphenol), 4,4′-[(2-hydroxyphenyl)methylene]-bis(2,3,6-trimethylphenol), 4,4′-[ 1-[4-[1-(4-hydroxy-3,5-dimethylphenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 4,4′-[1-[4 -[1-(4-hydroxy-3-fluorophenyl)-1-methylethyl]phenyl]ethylidene]bis(2,6-dimethylphenol), 2,6-bis[(4-hydroxy-3,5-dimethyl Phenyl)ethyl]-4-methylphenol, 2,6-bis[(4-hydroxy-2,3,6-trimethylphenyl)methyl]-4-methylphenol, 2,6-bis[(4-hydroxy-3 ,5,6-trimethylphenyl)methyl]-4-ethylphenol, 2,4-bis[(4-hydroxy-3-methylphenyl)methyl]-6-methylphenol, 2,6-bis[(4-hydroxy -3-methylphenyl)methyl]-4-methylphenol, 2,4-bis[(4-hydroxy-3-cyclohexylphenyl)methyl]-6-methylphenol, 2,4-bis[(4-hydroxy-3 -methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(2-hydroxy-5-methylphenyl)methyl]-6-cyclohexylphenol, 2,4-bis[(4-hydroxy-2,3 ,6-trimethylphenyl)methyl]-6-cyclohexylphenol, 3,6-bis[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2-benzenediol, 4,6-bis[(4 -hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6-tris[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,4,6-tris[(2-hydroxy-3,5-dimethylphenyl)methyl]-1,3-benzenediol, 2,2′-methylenebis[6-[(4/2-hydroxy-2,5 /3,6-dimethylphenyl)methyl]-4-methylphenol], 2,2′-methylenebis[6-[(4-hydroxy-3,5-dimethylphenyl)methyl]-4-methylphenol], 2, 2′-methylenebis[6-[(4/2-hydroxy-2,3,5/3,4,6-trimethylphenyl)methyl]-4-methylphenol], 2,2′-methylenebis[6-[( 4-hydroxy-2,3,5-trimethylphenyl)methyl]-4-methylphenol], 4,4′-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-6-methylphenol], 4 , 4′-methylenebis[2-[(2,4-dihydroxyphenyl)methyl]-3,6-dimethylphenol], 4,4′-methylenebis[2-[(2,4-dihydroxy-3-methylphenyl) methyl]-3,6-dimethylphenol], 4,4′-methylenebis[2-[(2,3,4-trihydroxyphenyl)methyl]-3,6-dimethylphenol], 6,6′-methylenebis[ 4-[(4-hydroxy-3,5-dimethylphenyl)methyl]-1,2,3-benzenetriol], 4,4′-cyclohexylidenebis[2-cyclohexyl-6-[(2-hydroxy- 5-methylphenyl)methyl]phenol], 4,4′-cyclohexylidenebis[2-cyclohexyl-6-[(4-hydroxy-3,5-dimethylphenyl)methyl]phenol], 4,4′-cyclohexyl sylidenebis[2-cyclohexyl-6-[(4-hydroxy-2-methyl-5-cyclohexylphenyl)methyl]phenol], 4,4′-cyclohexylidenebis[2-cyclohexyl-6-[(2, 3,4-trihydroxyphenyl)methyl]phenol], 4,4′,4″,4′″-(1,2-ethanediylidene)tetrakis(2,6-dimethylphenol), 4,4′,4 '',4''''-(1,4-phenylenedimethylidene)tetrakis(2,6-dimethylphenol), and the like, but are not limited thereto.

The number of phenolic hydroxyl groups in the polyhydric phenol compound is not particularly limited as long as it is 3 or more, but if the number of terminals of the polyphenylene ether increases, the molecular weight change during heating may increase, so it is preferably 3 to 6. number, more preferably 3 to 4.
Moreover, a methyl group is preferable as the 2,6-position alkyl group or alkylene group in the polyhydric phenol compound.

Most preferred polyhydric phenol compounds are 4,4′-[(4-hydroxyphenyl)methylene]bis(2,6-dimethylphenol), 4,4′-[(3-hydroxyphenyl)methylene]bis(2, 6-dimethylphenol), 4,4′-[(4-hydroxyphenyl)methylene]bis(2,3,6-trimethylphenol), 4,4′-[(3-hydroxyphenyl)methylene]bis(2, 3,6-trimethylphenol), 4,4′,4″,4′″-(1,4-phenylenedimethylidene)tetrakis(2,6-dimethylphenol).

<Method for producing polyphenylene ether>
In the method for producing polyphenylene ether of the present embodiment, it is preferable to use at least one type of aromatic solvent as the polymerization solvent, and a copper catalyst and an amine ligand as the polymerization catalyst. The polyphenylene ether of the present embodiment can be suitably obtained by the production method.

(Polymerization process)
Here, in the method for producing polyphenylene ether of the present embodiment, it is preferable to use an aromatic solvent, which is a good solvent for polyphenylene ether, as the polymerization solvent in the polymerization step.
Here, the good solvent for polyphenylene ether is a solvent capable of dissolving polyphenylene ether. aromatic hydrocarbons such as ethylbenzene and styrene; halogenated hydrocarbons such as chlorobenzene and dichlorobenzene; nitro compounds such as nitrobenzene;

As the polymerization catalyst used in the present embodiment, a known catalyst system that can be generally used for the production of polyphenylene ether can be used. As a generally known catalyst system, one comprising a transition metal ion having oxidation-reduction ability and an amine compound capable of forming a complex with the transition metal ion is known. For example, it comprises a copper compound and an amine compound. a catalyst system, a catalyst system comprising a manganese compound and an amine compound, a catalyst system comprising a cobalt compound and an amine compound, and the like. Since the polymerization reaction proceeds efficiently under slightly alkaline conditions, some alkali or additional amine compounds may be added here.

The polymerization catalyst preferably used in the present embodiment is a catalyst comprising a copper compound, a halogen compound and an amine compound as constituent components of the catalyst, and more preferably a diamine compound represented by the general formula (3) as the amine compound. is a catalyst containing

式（３）中、Ｒ^９、Ｒ^１０、Ｒ^１１、Ｒ^１２は、それぞれ独立に、水素原子、炭素数１から６の直鎖状又は分岐状アルキル基であり、全てが同時に水素原子ではない。Ｒ^１３は、炭素数２から５の直鎖状又はメチル分岐を持つアルキレン基である。

In formula (3), R ⁹ , R ¹⁰ , R ¹¹ , and R ¹² are each independently a hydrogen atom, a linear or branched alkyl group having 1 to 6 carbon atoms, and not all of them are hydrogen atoms at the same time. . R ¹³ is a linear or methyl-branched alkylene group having 2 to 5 carbon atoms.

Examples of copper compounds for the catalyst components described herein are listed. Suitable copper compounds may be cuprous compounds, cupric compounds or mixtures thereof. Examples of cupric compounds include cupric chloride, cupric bromide, cupric sulfate, and cupric nitrate. Examples of cuprous compounds include cuprous chloride, cuprous bromide, cuprous sulfate, and cuprous nitrate. Among these, particularly preferred metal compounds are cuprous chloride, cupric chloride, cuprous bromide and cupric bromide. These copper salts may also be synthesized from oxides (eg, cuprous oxide, cupric oxide), carbonates, hydroxides, etc. and corresponding halogens or acids at the time of use. A frequently used method is a method of mixing cuprous oxide and hydrogen halide (or a solution of hydrogen halide) as exemplified above.

Examples of halogen compounds include hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetramethylammonium chloride, and tetramethylammonium bromide. , tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide, and the like. Moreover, these can be used as an aqueous solution or a solution using a suitable solvent. These halogen compounds may be used alone as a component, or may be used in combination of two or more. Preferred halogen compounds are aqueous solutions of hydrogen chloride and hydrogen bromide.
The amount of these compounds to be used is not particularly limited, but is preferably 2 to 20 times as halogen atoms relative to the molar amount of copper atoms, and the use of copper atoms is preferable for 100 mol of the phenol compound added to the polymerization reaction. Amounts range from 0.02 mol to 0.6 mol.

Examples of diamine compounds as catalyst components are listed below. For example, N,N,N',N'-tetramethylethylenediamine, N,N,N'-trimethylethylenediamine, N,N'-dimethylethylenediamine, N,N-dimethylethylenediamine, N-methylethylenediamine, N,N, N',N'-tetraethylethylenediamine, N,N,N'-triethylethylenediamine, N,N'-diethylethylenediamine, N,N-diethylethylenediamine, N-ethylethylenediamine, N,N-dimethyl-N'-ethylethylenediamine , N,N'-dimethyl-N-ethylethylenediamine, Nn-propylethylenediamine, N,N'-n-propylethylenediamine, Ni-propylethylenediamine, N,N'-i-propylethylenediamine, Nn -butylethylenediamine, N,N'-n-butylethylenediamine, Ni-butylethylenediamine, N,N'-i-butylethylenediamine, Nt-butylethylenediamine, N,N'-t-butylethylenediamine, N, N,N',N'-tetramethyl-1,3-diaminopropane, N,N,N'-trimethyl-1,3-diaminopropane, N,N'-dimethyl-1,3-diaminopropane, N- methyl-1,3-diaminopropane, N,N,N',N'-tetramethyl-1,3-diamino-1-methylpropane, N,N,N',N'-tetramethyl-1,3- diamino-2-methylpropane, N,N,N',N'-tetramethyl-1,4-diaminobutane, N,N,N',N'-tetramethyl-1,5-diaminopentane and the like. . A preferred diamine compound for this embodiment is one in which the alkylene group connecting two nitrogen atoms has 2 or 3 carbon atoms. The amount of these diamine compounds to be used is not particularly limited, but is preferably in the range of 0.01 mol to 10 mol per 100 mol of the phenol compound added to the polymerization reaction.

In this embodiment, a primary amine and a secondary monoamine can be included as components of the polymerization catalyst. Examples of secondary monoamines include, but are not limited to, dimethylamine, diethylamine, di-n-propylamine, di-i-propylamine, di-n-butylamine, di-i-butylamine, Di-t-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine, N-phenylmethanolamine, N-phenylethanolamine , N-phenylpropanolamine, N-(m-methylphenyl)ethanolamine, N-(p-methylphenyl)ethanolamine, N-(2′,6′-dimethylphenyl)ethanolamine, N-(p-chlorophenyl ) ethanolamine, N-ethylaniline, N-butylaniline, N-methyl-2-methylaniline, N-methyl-2,6-dimethylaniline, diphenylamine and the like.

A tertiary monoamine compound can also be included as a constituent component of the polymerization catalyst in the present embodiment. Tertiary monoamine compounds are aliphatic tertiary amines including alicyclic tertiary amines. Examples include trimethylamine, triethylamine, tripropylamine, tributylamine, triisobutylamine, dimethylethylamine, dimethylpropylamine, allyldiethylamine, dimethyl-n-butylamine, diethylisopropylamine, N-methylcyclohexylamine and the like. These tertiary monoamines may be used alone or in combination of two or more. The amount of these used is not particularly limited, but is preferably in the range of 15 mol or less per 100 mol of the phenol compound added to the polymerization reaction.

In the present embodiment, the addition of surfactants that are conventionally known to have an effect of improving polymerization activity is not limited at all. Such surfactants include, for example, trioctylmethylammonium chloride known under the trade names of Aliquat 336 and Capriquat. The amount used is preferably within a range not exceeding 0.1% by mass with respect to 100% by mass of the total amount of the polymerization reaction mixture.

As the oxygen-containing gas in the polymerization of the present embodiment, in addition to pure oxygen, a mixture of oxygen and an inert gas such as nitrogen at an arbitrary ratio, air, and air and an inert gas such as nitrogen are optionally used. can be used. Normal pressure is sufficient for the system internal pressure during the polymerization reaction, but if necessary, either reduced pressure or increased pressure can be used.

The polymerization temperature is not particularly limited, but if it is too low, the reaction will not progress easily. °C range.

(Copper extraction and by-product removal step)
In the present embodiment, there are no particular restrictions on the post-treatment method after the completion of the polymerization reaction. Generally, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid (EDTA) and its salts, nitrilotriacetic acid and its salts, etc. are added to the reaction solution to deactivate the catalyst. A conventionally known method can also be used to remove dihydric phenol by-products produced by polymerization of polyphenylene ether. As described above, when the metal ions that are the catalyst are substantially deactivated, the mixture is decolorized simply by heating. A method of adding a required amount of a known reducing agent can also be used. Known reducing agents include hydroquinone, sodium dithionite, and the like.

(Liquid-liquid separation step)
In the method for producing polyphenylene ether of the present embodiment, water is added to extract the compound in which the copper catalyst is deactivated, and the organic phase and the aqueous phase are subjected to liquid-liquid separation, and then the aqueous phase is removed. A copper catalyst may be removed from the substrate. This liquid-liquid separation step is not particularly limited, but methods such as static separation and separation using a centrifugal separator can be used. A known surfactant or the like may be used to promote the liquid-liquid separation.

(concentration/drying process)
Subsequently, in the method for producing polyphenylene ether of the present embodiment, the organic phase containing the polyphenylene ether after the liquid-liquid separation may be concentrated and dried by volatilizing the solvent.

The method for volatilizing the solvent contained in the organic phase is not particularly limited, but a method of transferring the organic phase to a high-temperature concentration tank and distilling off the solvent to concentrate, or distilling toluene using a device such as a rotary evaporator. A method of removing and concentrating is mentioned.

The temperature of the drying treatment in the drying step is preferably at least 60° C. or higher, more preferably 80° C. or higher, still more preferably 120° C. or higher, and most preferably 140° C. or higher. By drying the polyphenylene ether at a temperature of 60° C. or higher, the content of high-boiling volatile components in the polyphenylene ether powder can be efficiently reduced.

In order to obtain polyphenylene ether with high efficiency, a method of increasing the drying temperature, a method of increasing the degree of vacuum in the drying atmosphere, a method of stirring during drying, and the like are effective. The method is preferred from the viewpoint of manufacturing efficiency. The drying step preferably uses a dryer with a mixing function. The mixing function includes a stirring type dryer, a tumbling type dryer, and the like. As a result, the throughput can be increased, and productivity can be maintained at a high level.

The method for producing the polyphenylene ether of the present embodiment is not limited to the method for producing the polyphenylene ether of the present embodiment described above. - The order and number of drying steps may be adjusted as appropriate. In addition, in order to reduce impurities such as residual polymerization solvent and residual catalyst, a precipitation step of precipitating polyphenylene ether by mixing a polymerization solution of polyphenylene ether and a poor solvent of polyphenylene ether as necessary to produce a slurry. Furthermore, a washing step of washing the precipitated polyphenylene ether with a poor solvent may be incorporated as appropriate.

EXAMPLES The present embodiment will be described in more detail below based on examples, but the present embodiment is not limited to the following examples.

First, the measuring method will be described below.

(1) Measurement of reduced viscosity (η sp / c) A 0.5 g / dL chloroform solution of polyphenylene ether was prepared, and the reduced viscosity (η sp / c) (dL / g) at 30 ° C. was obtained using an Ubbelohde viscosity tube. rice field.

Methods for producing 2,6-dimethylphenol and polyphenylene ether in Examples and Comparative Examples are described below.

(Example 1)
According to the method described in Example 9 of JP-A-2018-62492, the hydrogenolysis reaction of lignin was performed to obtain high-purity unsubstituted phenol. Furthermore, according to Example 1 of Japanese Patent Application Laid-Open No. 10-113561, by reacting the isolated renewable raw material phenol with petrochemical-derived methanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), A synthesized 2,6-dimethylphenol was obtained.

(Example 2)
In the same manner as in Example 1, except that methanol (70% plant-derived) produced from glycerin produced when obtaining biodiesel was reacted with petrochemical-derived phenol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.). 2,6-Dimethylphenol synthesized from renewable raw materials was obtained.

(Example 3)
Methanol produced from glycerin produced when obtaining biodiesel (70% plant-derived), according to the method described in Example 9 of JP 2018-62492, high-purity obtained by the hydrocracking reaction of lignin. 2,6-dimethylphenol synthesized from renewable raw materials was obtained in the same manner as in Example 1, except that unsubstituted phenol was reacted.

(Comparative example 1)
According to Example 1 of JP-A-10-113561, by reacting petrochemical-derived methanol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.) and petrochemical-derived phenol (reagent manufactured by Tokyo Chemical Industry Co., Ltd.), petrochemical 2,6-dimethylphenol synthesized from raw materials derived from

(Example 4)
A 1 liter jacketed polymerization vessel equipped with a sparger for introducing an oxygen-containing gas at the bottom of the polymerization vessel, a stirring turbine blade and baffles, and a reflux condenser in the vent gas line at the top of the polymerization vessel was charged with 0.9 L/min. While blowing nitrogen gas at a flow rate, 0.075 g of cupric oxide, 0.56 g of 47% by mass aqueous hydrogen bromide solution, 0.18 g of di-t-butylethylenediamine, 0.87 g of di-n-butylamine, 2.7 g of butyldimethylamine, 520 g of toluene, and 57.8 g of 2,6-dimethylphenol of Example 1 were added to form a homogeneous solution. Next, introduction of dry air into the polymerization tank from a sparger was started at a rate of 0.6 L/min to initiate polymerization. Dry air was passed through for 120 minutes to obtain a polymerization mixture. The internal temperature was controlled to 40°C during the polymerization. The polymerization mixture (polymerization liquid) at the end of the polymerization was in a uniform solution state.
Dry air was stopped, and 0.80 g of tetrasodium ethylenediaminetetraacetic acid (Dojindo Laboratories reagent) was added to the polymerization mixture as an aqueous solution of 60 g of water. The polymerization mixture was stirred at 70° C. for 150 minutes, then allowed to stand for 20 minutes, and an organic phase and an aqueous phase were separated by liquid-liquid separation. The organic phase was solidified by a rotary evaporator and then held at 140° C. and 1 mmHg for 120 minutes to obtain a dry polyphenylene ether.
The resulting polyphenylene ether was measured for reduced viscosity by the method described above and found to be 0.30 dL/g.

(Comparative example 2)
The procedure of Example 4 was repeated except that 2,6-dimethylphenol of Comparative Example 1 was used. The resulting polyphenylene ether was measured for reduced viscosity by the method described above and found to be 0.30 dL/g.

(Example 5)
A polyphenylene ether was obtained in the same manner as in Example 4 except that 2,6-dimethylphenol of Example 2 was used. The resulting polyphenylene ether was measured for reduced viscosity by the method described above and found to be 0.30 dL/g.

(Example 6)
A polyphenylene ether was obtained in the same manner as in Example 4 except that 2,6-dimethylphenol of Example 3 was used. The resulting polyphenylene ether was measured for reduced viscosity by the method described above and found to be 0.30 dL/g.

Since the reduced viscosities of Comparative Example 2 and Examples 4, 5, and 6 were equivalent, 2,6-dimethylphenol synthesized from renewable raw materials was equivalent to 2,6-dimethylphenol derived from fossil resources. It was shown to have polymerization activity.

According to the present invention, it is possible to provide 2,6-dimethylphenol and its oxidation polymer, polyphenylene ether, which meets the demands of a recycling-oriented society, has a low environmental load, and is sustainable. is worth using.

Claims (4)

2,6-dimethylphenol obtained by the reaction of phenol and methanol, characterized in that at least one of said phenol and said methanol comprises a renewable raw material. 2,6-dimethylphenol according to claim 1, wherein the renewable raw material phenol is derived from biomass and/or the renewable raw material methanol is derived from biomass. 2,6-dimethylphenol according to claim 1, wherein the renewable feedstock methanol is derived from carbon dioxide. A polyphenylene ether obtained by the oxidation polymerization reaction of 2,6-dimethylphenol according to any one of claims 1 to 3.