JP2006265298A - Process of polymerization of polyphenylene ether - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a process of polymerization of a polyphenylene ether which is capable of stably controlling the molecular weight at a desired value. <P>SOLUTION: The process of polymerization of a polyphenylene ether gives a polyphenylene ether with a number average molecular weight of 1,000-20,000 by polymerizing a phenol in the presence of a polymerization medium, a catalyst and a oxygen-containing gas. The content of the phenol in the polymerization medium is 25-60 wt.%. <P>COPYRIGHT: (C)2007,JPO&amp;INPIT

Description

  The present invention relates to a method for efficiently producing polyphenylene ether having a number average molecular weight of 1,000 to 20,000.

Polyphenylene ether is excellent in processability and productivity, and can efficiently produce products and parts of the desired shape by molding methods such as melt injection molding and melt extrusion molding. It is widely used as a material for products and parts in the field of industrial materials and food packaging.
Recently, in response to the demand for new industrial applications for polyphenylene ether, polyphenylene ether having various molecular weights in a wider range than before is effective for modification of other resins and electronic material applications. Therefore, an efficient method for producing polyphenylene ether having various molecular weights has been desired.

  As a method for producing a relatively low molecular weight polyphenylene ether, a production method has been proposed in which the molecular weight of polyphenylene ether obtained by adding 2,4,6-trimethylphenol is changed according to the amount added (see, for example, Patent Document 1). In this specification, a mixed solvent of a good solvent of polyphenylene ether (for example, benzene, toluene, xylene) and a non-solvent of polyphenylene ether (for example, ketone, ether, alcohol) is used as a solvent. It has been proposed that polymers of various molecular weights can be obtained by changing the solvent ratio. However, it is stated that this method is inaccurate and is not suitable as a method for obtaining a polymer having a required molecular weight. Further, a method of redistributing a high molecular weight polyphenylene ether and a divalent phenol under a radical catalyst to convert the high molecular weight polyphenylene ether into a low molecular weight polyphenylene ether (for example, see Patent Document 2), It has a step of synthesizing 0.39 polyphenylene ether and a step of synthesizing polyphenylene ether with intrinsic viscosity of 0.40 to 0.65, and these are mixed to produce polyphenylene ether with intrinsic viscosity of 0.3 to 0.6 A method (for example, see Patent Document 3) is also known.

However, these methods are not suitable when productivity is taken into consideration, and high molecular weight substances are also mixed, and polyphenylene ethers having a desired molecular weight cannot be obtained efficiently.
Further, as a method for producing a low molecular weight polyphenylene ether resin, which is typically in an intrinsic viscosity range of about 0.08 to about 0.16 dl / g as measured in chloroform at 25 ° C., the reaction solvent is devolatilized. A method including the isolation of polyphenylene ether has been proposed (for example, see Patent Document 4), and it is convenient to determine the end point of polymerization with an in-line viscometer, but the molecular weight is measured up to a predetermined reaction time. Methods such as continuing the reaction, adjusting to a predetermined end group concentration, and adjusting the oxygen concentration in the solution have been proposed. To control the end point of the polymerization under the same reaction conditions, it is effective to use these methods including an in-line viscometer. However, polyphenylene ethers having a wide variety of molecular weights which have been desired recently are used. In order to produce, in reality, a substantial process change and reaction condition change are involved, and the end point control of the polymerization results in complication. Therefore, an efficient method for producing polyphenylene ether that can be stably controlled to a desired molecular weight in a wide range is desired.

U.S. Pat. No. 3,440,217 JP-A-9-291148 JP 2000-281780 A JP 2002-536476 A

  The subject in this invention is providing the manufacturing method of the polyphenylene ether which can manufacture stably the polyphenylene ether whose number average molecular weight is 1000-20000 stably.

As a result of intensive research to solve the above problems, the present inventor has optimized the content of phenols in the polymerization solution, thereby improving the accuracy of the polymerization end point control and stably controlling to the desired molecular weight. As a result, the inventors have found out that the present invention can be achieved.
That is, the present invention
[1] A method for producing polyphenylene ether by polymerizing phenols in the presence of a polymerization solvent, a catalyst and an oxygen-containing gas, wherein the content of phenols in the polymerization solution is 25 to 60% by weight. Polymerization method of polyphenylene ether having a number average molecular weight of 1000 to 20000,
[2] The polyphenylene ether polymerization method according to [1], wherein the content of phenols in the polymerization solution is 25% by weight or more and less than 35% by weight, and the number average molecular weight is 10,000 to 20,000.
[3] The polymerization method of polyphenylene ether according to [1], wherein the content of phenol in the polymerization solution is 35% by weight or more and less than 45% by weight, and the number average molecular weight is 3000 to 10,000.
[4] The polymerization method of polyphenylene ether according to [1], wherein the content of phenols in the polymerization solution is 45% by weight or more and 55% by weight or less, and the number average molecular weight is 1000 to 3000.
[5] The polymerization method of polyphenylene ether according to any one of [1] to [4], wherein the polymerization solvent is one or more selected from C _{6 to} C ₁₈ aromatic hydrocarbons and halogenated hydrocarbons. ,
[6] The method for polymerizing a polyphenylene ether according to any one of [1] to [5], wherein a catalyst component is a copper compound, a halogen compound, and a catalyst comprising a diamine compound represented by the general formula (1).

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, and all are not hydrogen at the same time. R ₅ has 2 carbon atoms. To 5 linear or methyl branched alkylene groups.)
It is.

  According to the polymerization method of polyphenylene ether of the present invention, the accuracy of controlling the polymerization end point can be improved, the molecular weight can be stably controlled, and polyphenylene ether can be efficiently produced.

The present invention will be specifically described below.
The present invention is a process for producing a polyphenylene ether having a number average molecular weight of 1,000 to 20,000 by polymerizing phenols in the presence of a catalyst and an oxygen-containing gas.
In the present invention, the number average molecular weight of polyphenylene ether was determined by measuring by gel permeation chromatography.
The phenols used in the present invention are compounds represented by the following general formula (2).

(In the formula, R ₆ , R ₇ and R ₈ each represents an independent substituent, and R ₆ represents an alkyl group, a substituted alkyl group, an aralkyl group, a substituted aralkyl group, an aryl group, a substituted aryl group, an alkoxy group, and a substituted alkoxy group. And R ₇ and R ₈ may be hydrogen or halogen in addition to the same groups defined for R _6. )

  Examples of monohydric phenols represented by the general formula (2) include o-cresol, 2,6-dimethylphenol, 2,3,6-trimethylphenol, 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 Le, 2,6-bis - (4-fluorophenyl) phenol, 2-methyl-6-tolyl, 2,6-di-tolyl phenols, and the like.

Among these monohydric phenolic compounds in the present invention, 2,6-dimethylphenol is very important industrially and is preferably used. These monohydric phenolic compounds may be used alone or in combination. For example, a method using a combination of 2,6-dimethylphenol and 2,3,6-trimethylphenol, a method using a combination of 2,6-dimethylphenol and 2,6-diphenylphenol, and the like are preferably used. When such a mixed monohydric phenol is used, it is to use a mixed monohydric phenol having a weight ratio of 2,99-99: 1 to 2,6-dimethylphenol.
The compound used may contain a small amount of m-cresol, p-cresol, 2,4-dimethylphenol, 2,4,6-trimethylphenol and the like.
Moreover, it is also possible to contain the dihydric phenol compound represented by following General formula (3) as phenols.

(In the formula, Q ₁ and Q ₂ each represent the same or different substituents, hydrogen, alkyl group, substituted alkyl group, aralkyl group, substituted aralkyl group, aryl group, substituted aryl group, alkoxy group, substituted alkoxy group, halogen X represents an aliphatic hydrocarbon residue and a substituted derivative thereof, oxygen, sulfur, and a sulfonyl group, and the bonding position of Q ₂ and X represents an ortho position or a para position with respect to the phenol hydroxyl group.

The dihydric phenolic compound represented by the general formula (3) can be advantageously produced industrially by reacting the corresponding monohydric phenolic compound with a ketone or a dihalogenated aliphatic hydrocarbon. For example, it is a compound group obtained by a reaction of a monovalent phenolic compound with a general-purpose ketone compound such as formaldehyde, acetone, methyl ethyl ketone, methyl isobutyl ketone, acetophenone, and cyclohexanone.
A representative compound having a structure of the above general formula is a compound in which Q ₁ and Q ₂ are methyl groups and X is isopropylidene, a compound in which Q ₁ and Q ₂ are methyl groups, and X is methylene, Q ₁ And Q ₂ are methyl groups and X is thio, and Q ₁ and Q ₂ are methyl groups and X is cyclohexylidene. However, it goes without saying that these examples are not limiting.
These dihydric phenolic compounds may be used alone or in combination.
When the dihydric phenolic compound represented by the general formula (3) is contained, the amount of the dihydric phenolic compound of the general formula (3) with respect to the monohydric phenol described in the general formula (2) is not particularly limited. However, it is preferable to set it as 0.1 to 30 mol% with respect to monohydric phenols.

A feature of the present invention is that the content of phenols in the polymerization solution is 25 to 60% by weight. By optimizing the content of phenols, the accuracy of polymerization end point control is improved, and the desired molecular weight is reduced. It becomes possible to produce polyphenylene ether.
The preferred content of phenols in the polymerization solution is preferably 25% by weight or more and less than 35% by weight, whereby polyphenylene ether having a number average molecular weight of 10,000 to 20,000 can be suitably controlled, and 35% by weight or more and less than 45% by weight. The polyphenylene ether having a number average molecular weight of 3000 to 10,000 can be suitably controlled, and the polyphenylene ether having a number average molecular weight of 1000 to 3000 can be suitably controlled by adjusting the number average molecular weight to 45 to 55% by weight. .

Further, the method for supplying phenols is not particularly limited, but by continuously supplying to the polymerization solution in which the catalyst and the oxygen-containing gas are present, the accumulation of unreacted monomers is reduced, and unnecessary by-products of the dihydric phenol compound are produced. This is preferable because the production amount of is reduced.
As the catalyst used in the present invention, any known catalyst system that can be generally used for production of polyphenylene ether can be used. Known catalyst systems include those composed of transition metal ions having redox ability and amine compounds capable of complexing with the metal ions. For example, catalyst systems composed of copper compounds and amines, manganese A catalyst system comprising a compound and an amine, a catalyst system comprising a cobalt compound and an amine, and the like. Since the polymerization reaction proceeds efficiently under some alkaline conditions, some alkali or further amine may be added thereto.
The catalyst suitably used in the present invention is to use a catalyst comprising a copper compound, a halogen compound and a diamine compound represented by the general formula (1) as a constituent component of the catalyst.

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, and all are not hydrogen at the same time. R ₅ has 2 carbon atoms. To 5 linear or methyl branched alkylene groups)

Examples of the copper compounds of the catalyst component described here are listed. As a suitable copper compound, a cuprous compound, a cupric compound or a mixture thereof can be used.
Examples of the cupric compound 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. In addition, these copper salts may be synthesized at the time of use from oxides (for example, cuprous oxide), carbonates, hydroxides, and the corresponding halogens or acids. A method often used is a method in which cuprous oxide and hydrogen halide (or a solution of hydrogen halide) exemplified above are mixed and prepared.

Examples of the halogen compound include hydrogen chloride, hydrogen bromide, hydrogen iodide, sodium chloride, sodium bromide, sodium iodide, potassium chloride, potassium bromide, potassium iodide, tetramethylammonium chloride, tetramethylammonium bromide, iodine. Tetramethylammonium iodide, tetraethylammonium chloride, tetraethylammonium bromide, tetraethylammonium iodide and the like. These can be used as an aqueous solution or a solution using an appropriate solvent. These halogen compounds may be used alone as a component or in combination of two or more. Preferred halogen compounds are an aqueous solution of hydrogen chloride and an aqueous solution of hydrogen bromide.
Although the usage-amount of these compounds is not specifically limited, 2 times or more and 20 times or less are preferable as a halogen atom with respect to the molar amount of a copper atom, As a preferable usage amount of a copper atom with respect to 100 mol of the phenol used, The range is from 0.02 mol to 0.6 mol.

  Next, the example of the diamine compound of a catalyst component is enumerated. 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′-di-n-propylethylenediamine, Ni-propylethylenediamine, N, N′-di-i-propylethylenediamine, Nn-butylethylenediamine N, N'-di-n-butylethylenediamine, Ni-butylethylenediamine, N, N'-di-butylethylenediamine, Nt-butylethylenediamine, N, N'-di-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, etc. Is mentioned. Preferred diamine compounds for the present invention are those in which the alkylene group connecting two nitrogen atoms has 2 or 3 carbon atoms. Although the usage-amount of these diamine compounds is not specifically limited, It is used in 0.01 mol-10 mol with respect to 100 mol of phenol normally used.

In the present invention, it is preferable to further include a tertiary monoamine compound or a secondary monoamine compound alone or in combination as a constituent component of the catalyst.
The tertiary monoamine compound is an aliphatic tertiary amine including an alicyclic tertiary amine. 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. Although the usage-amount of these is not specifically limited, The range of 15 mol or less is preferable with respect to 100 mol of phenol normally used.

  Examples of secondary monoamine compounds include secondary aliphatic amines such as dimethylamine, diethylamine, di-n-propylamine, di-iso-propylamine, di-n-butylamine, di-iso-butylamine, di- -Tert-butylamine, dipentylamines, dihexylamines, dioctylamines, didecylamines, dibenzylamines, methylethylamine, methylpropylamine, methylbutylamine, cyclohexylamine. Examples of secondary monoamine compounds containing aromatics include 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 Examples include -2,6-dimethylaniline and diphenylamine, but are not limited to these examples. These secondary monoamine compounds may be used alone or in combination of two or more. Although the usage-amount is not specifically limited, The range of 15 mol or less is preferable with respect to 100 mol of the phenol normally used.

The secondary monoamine compound and the tertiary monoamine compound may be used alone as a constituent component of the catalyst, respectively, or may be used in combination.
In the present invention, there is no limitation on adding a surfactant known to have an improvement effect on activity. 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 wt% with respect to the total amount of the polymerization reaction mixture.
The oxygen-containing gas in the polymerization of the present invention is pure oxygen, oxygen and an inert gas such as nitrogen mixed at an arbitrary ratio, air, and further an inert gas such as air and nitrogen at an arbitrary ratio. A mixture or the like can be used. The system pressure during the polymerization reaction is normal pressure, but it can be used under reduced pressure or increased pressure as necessary. Of these, preferred oxygen-containing gases are pure oxygen and air. The supply amount of the oxygen-containing gas is preferably an amount sufficient to polymerize the phenols, that is, 0.5 mol or more of oxygen is preferable with respect to 1 mol of the phenols, and more preferably 0.5 to 20 mol is supplied.
The temperature of the polymerization is not particularly limited, but if it is too low, the reaction does not proceed easily, and if it is too high, the selectivity of the reaction may be lowered, so it is in the range of 0 to 80 ° C., preferably 30 to 50 ° C.

As the polymerization solvent of the present invention, various good solvents generally used for polymerization of polyphenylene ether can be used. The good solvent used for polymerization of polyphenylene ether is a solvent that can dissolve polyphenylene ether. Examples of such a solvent, benzene, toluene, xylene (o-, m-, including each isomer of p-), ethylbenzene, _C 6 _{-C 18} aromatic hydrocarbons, such as styrene, chloroform, methylene chloride, Examples thereof include halogenated hydrocarbons such as 1,2-dichloroethane, chlorobenzene and dichlorobenzene, and nitro compounds such as nitrobenzene. Moreover, although it has some poor solvent property, what is classified as a good solvent includes aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane and cycloheptane, esters such as ethyl acetate and ethyl formate, Examples thereof include ethers such as tetrahydrofuran and diethyl ether, dimethyl sulfoxide and the like. These good solvents may be used alone or in combination of two or more. Among these, preferable good solvents include C _{6 to} C ₁₈ aromatic hydrocarbons such as benzene, toluene, xylene (including o-, m-, and p-isomers), ethylbenzene, styrene, chlorobenzene, and dichlorobenzene. include halogenated hydrocarbons like benzene, toluene, xylene (o-, m-, including each isomer of p-), ethylbenzene, and _C 6 _{-C 18} aromatic hydrocarbons, such as styrene, more preferably.

The mode of the polymerization tank for obtaining the polyphenylene ether of the present invention is not particularly limited. The polymerization may be completed in one polymerization tank, or the polymerization may be completed using two or more polymerization tanks.
There is no restriction | limiting in particular about the post-processing method after completion | finish of a polymerization reaction. Usually, an acid such as hydrochloric acid or acetic acid, or a metal chelating agent such as ethylenediaminetetraacetic acid (EDTA) and its salt, nitrilotriacetic acid and its salt is added to the reaction solution to deactivate the catalyst. For the purpose of suppressing the corrosion of the reaction tank, it is preferable to use a metal chelating agent, and a method of recovering the deactivated metal complex of the catalyst with an aqueous solution is generally used. For the purpose of promoting the equilibration of the metal chelating agent and the catalyst, it is also preferable to carry out the equilibration at 40 to 100 ° C.

Moreover, the method of processing the by-product of the bihydric phenol body which arises by superposition | polymerization of polyphenylene ether can also be performed using a conventionally well-known method. If the metal ion which is a catalyst is in a substantially deactivated state as described above, it is decolorized only by heating the mixture. A method of adding a necessary amount of a known reducing agent is also possible. Known reducing agents include hydroquinone, sodium dithionite, and the like. Thereafter, for the purpose of washing and removing the catalyst, it is preferable to carry out washing repeatedly using a solution containing a poor solvent as a main component. Thereafter, polyphenylene ether can be recovered by an operation of drying in a drying process using various dryers.
Next, the present invention will be described by way of examples. The number average molecular weight was measured by gel permeation chromatography (GPC) using a calibration curve with standard polystyrene.

[Example 1]
A flow rate of 7.0 l / min into a 1.5 liter jacketed polymerization tank equipped with a sparger for introducing an oxygen-containing gas, a stirring turbine blade, a baffle, a thermometer, and a reflux condenser in the vent gas line at the top of the polymerization tank 0.64 g of cuprous oxide, 4.84 g of 47% aqueous hydrogen bromide, 1.86 g of N, N′-tert-butylethylenediamine, 7.51 g of di-n-butylamine 16.01 g of dimethyl-n-butylamine, 469.1 g of toluene, and 500.0 g of 2,6-dimethylphenol were added and mixed by stirring. The content of 2,6-dimethylphenol in this solution is 50% by weight. Subsequently, oxygen was introduced from the sparger at a rate of 760 ml / min (this oxygen flow rate corresponds to a flow rate at which oxygen necessary for polymerization can be supplied in about 60 minutes in theory).
During the polymerization, a heating medium was adjusted through the jacket so that the reaction solution maintained at 40 ° C.
In order to measure the molecular weight, about 2 g of the reaction solution was extracted from the polymerization tank at 100 minutes, 120 minutes, and 140 minutes after the introduction of oxygen, and 0.3 g of a 10% aqueous solution of tripotassium ethylenediaminetetraacetate was added.
The extracted reaction solution was adjusted to a chloroform solution containing about 0.1% by weight of polyphenylene ether, and the number average molecular weight was measured. The results are shown in Table 1.

[Example 2]
While nitrogen gas was blown into a 1.5 liter jacketed polymerization tank at a flow rate of 6.0 l / min, 0.52 g of cuprous oxide, 3.88 g of 47% hydrogen bromide water, 1.49 g of N , N'-t-butylethylenediamine, 6.01 g di-n-butylamine, 12.81 g dimethyl-n-butylamine, 575.3 g toluene, 400.0 g 2,6-dimethylphenol Were mixed. The content of 2,6-dimethylphenol in this solution is 40% by weight. Subsequently, oxygen was introduced from the sparger at a rate of 610 ml / min. (The flow rate of oxygen corresponds to a flow rate that can theoretically supply oxygen required for polymerization in about 60 minutes.) Other operations and measurements were performed in the same manner as in Example 1, and the results are shown in Table 1.

[Example 3]
While nitrogen gas was blown into a 1.5 liter jacketed polymerization tank at a flow rate of 4.5 l / min, 0.39 g of cuprous oxide, 2.91 g of 47% hydrogen bromide water, 1.11 g of N N'-t-butylethylenediamine, 4.51 g di-n-butylamine, 9.60 g dimethyl-n-butylamine, 681.5 g toluene, 300.0 g 2,6-dimethylphenol Were mixed. The content of 2,6-dimethylphenol in this solution is 30% by weight. Subsequently, oxygen was introduced from the sparger at a rate of 460 ml / min. (The flow rate of oxygen corresponds to a flow rate that can theoretically supply oxygen required for polymerization in about 60 minutes.) Other operations and measurements were performed in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Example 1]
While nitrogen gas was blown into a 1.5 liter jacketed polymerization tank at a flow rate of 3.0 l / min, 0.26 g of cuprous oxide, 1.94 g of 47% hydrogen bromide water, 0.74 g of N N'-t-butylethylenediamine, 3.01 g di-n-butylamine, 6.40 g dimethyl-n-butylamine, 787.7 g toluene, 200.0 g 2,6-dimethylphenol Were mixed. The content of 2,6-dimethylphenol in this solution is 20% by weight. Subsequently, introduction of oxygen from the sparger was started at a rate of 300 ml / min (this oxygen flow rate corresponds to a flow rate at which oxygen necessary for polymerization can be supplied in about 60 minutes in theory). Other operations and measurements were performed in the same manner as in Example 1, and the results are shown in Table 1.

[Comparative Example 2]
While nitrogen gas was blown into a 1.5 liter jacketed polymerization tank at a flow rate of 1.5 l / min, 0.13 g of cuprous oxide, 0.97 g of 47% hydrogen bromide water, 0.37 g of N N'-t-butylethylenediamine, 1.50 g di-n-butylamine, 3.20 g dimethyl-n-butylamine, 893.8 g toluene, 100.0 g 2,6-dimethylphenol Were mixed. The content of 2,6-dimethylphenol in this solution is 10% by weight. Next, oxygen was introduced from the sparger at a rate of 150 ml / min. (The flow rate of oxygen corresponds to a flow rate that can theoretically supply oxygen required for polymerization in about 60 minutes.) Other operations and measurements were performed in the same manner as in Example 1, and the results are shown in Table 1.

  As is apparent from Table 1, by employing the polymerization method of the present invention, it becomes possible to produce polyphenylene ethers having a wide range of molecular weights, and the fluctuation of molecular weight due to polymerization time can be greatly suppressed. That is, by selecting the content of phenols within the scope of the present invention, the accuracy of polymerization end point control is increased, and polyphenylene ethers having various desired molecular weights can be produced efficiently and stably.

  It is suitable as a polymerization method of polyphenylene ether that can be stably controlled to a desired molecular weight.

Claims (6)

  In the method for producing a polyphenylene ether by polymerizing phenols in the presence of a polymerization solvent, a catalyst and an oxygen-containing gas, the number average molecular weight of the phenolic solution in the polymerization solution is 25 to 60% by weight Polymerization method of polyphenylene ether in which is 1000-20000.   The method for polymerizing polyphenylene ether according to claim 1, wherein the content of phenol in the polymerization solution is 25 wt% or more and less than 35 wt%, and the number average molecular weight is 10,000 to 20,000.   The method for polymerizing a polyphenylene ether according to claim 1, wherein the content of phenols in the polymerization solution is 35 wt% or more and less than 45 wt%, and the number average molecular weight is 3000 to 10,000.   The method for polymerizing polyphenylene ether according to claim 1, wherein the content of phenols in the polymerization solution is 45 wt% or more and 55 wt% or less, and the number average molecular weight is 1000 to 3000. The polymerization method for polyphenylene ether according to any one of claims 1 to 4, wherein the polymerization solvent is one or more selected from C _{6 to} C ₁₈ aromatic hydrocarbons and halogenated hydrocarbons. The method for polymerizing polyphenylene ether according to any one of claims 1 to 5, wherein a catalyst is used as a constituent component of the catalyst comprising a copper compound, a halogen compound and a diamine compound represented by the general formula (1).

(In the formula, R ₁ , R ₂ , R ₃ and R ₄ are each independently hydrogen, a linear or branched alkyl group having 1 to 6 carbon atoms, and all are not hydrogen at the same time. R ₅ has 2 carbon atoms. To 5 linear or methyl branched alkylene groups.)