JPH0812753A - Production of polyphenylene ether - Google Patents

Abstract

PURPOSE:To produce economically a polyphenylene ether reduced in thermal coloration, especially yellowness, and in the content of nitrogen causative of malodor and having a narrow molecular weight distribution. CONSTITUTION:A process for producing a polyphenylene ether by polymerizing a nucleus-substituted phenol through oxidation with an oxygenous gas in the presence of a catalyst containing a sec. amine represented by the formula: R1R2NH (wherein R1 and R2 represent each independently 1-12 C alkyl, substituted alkyl, alkenyl or substituted alkenyl, provided that R1 and R2 may be combined with each other to form a ring) and a transition metal compound, wherein the polymerization temperatures are 35 to 100 deg.C and 5 to below 35 deg.C, respectively, before the oxygen consumption reaches 50 to below 80% of the theoretical amount of oxygen necessary for completing the polymerization and after the oxygen consumption reaches the specified amount.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to a method for producing polyphenylene ether.

[0002]

2. Description of the Related Art Polyphenylene ethers obtained by oxidative polymerization of nuclear-substituted phenols are known to be useful resins. In particular, a polymer alloy of this and polystyrene or polyamide has excellent thermal properties, mechanical properties, electrical properties, and the like, and in recent years, its application as a molding material has spread to the fields of automobiles, electric / electronics, and the like. Conventionally,
Various methods for producing polyphenylene ether by oxidatively polymerizing a nuclear-substituted phenol in the presence of a transition metal compound catalyst system such as manganese, copper or cobalt are known.
Among them, the method of using a catalyst system containing a secondary amine is extremely useful in practice since it can greatly improve the impact properties of the molded article. For example, as a manganese catalyst system containing a secondary amine, a catalyst system in which a manganese compound, an alkanolamine, a basic compound and a secondary amine coexist (Japanese Patent Publication No.
No. 23291, JP-A No. 62-240322), and a catalyst system in which a diol is further coexisted (JP-A-1-264).
No. 304119), and the like. As a copper catalyst system containing a secondary amine, a catalyst system in which a copper compound, a diamine, a tertiary amine, a bromine-containing compound and a secondary amine are allowed to coexist (Japanese Patent Laid-Open Publication No. Sho. No. 53-30698). However, the polyphenylene ether obtained with a catalyst system containing a secondary amine is a secondary amine (Macromolecules, attached to the end of the polymer).
1990, Vol. 23, 1318-1329), and has a drawback that it emits an unpleasant odor, and there is a problem that the amount of coloring increases during heating and melting.

A method of carrying out the polymerization at a low temperature is known as one of effective means for improving the heat coloration, but since the polymerization is a large exothermic reaction, it is costly to keep the polymerization at a low temperature. It has the drawback. On the other hand, as an economical method for improving thermal coloring, after the oxygen consumption amount during the polymerization reaches 80 to 100% of the theoretical oxygen value required for the completion of the polymerization, the polymerization temperature is lowered to at least 5 ° C lower than before. A control method (Japanese Patent Laid-Open No. 2-67318) has been proposed. However, although the coloring of the molded article is considerably improved by this method, the coloring, particularly the yellowish tint, cannot be said to be sufficiently satisfactory as compared with colorless engineering plastics such as polycarbonate. Amount of bound amine (corresponding to nitrogen content)
There is no description about reduction of. Further, in the continuous polymerization method, the polymerization rate of the first tank is kept at 50% or more and 95% or less, and the produced water is distilled off, and the polymerization is completed in the second tank and thereafter (Japanese Patent Publication No. 50-6358). Is proposed,
The temperature after the second tank is 40 ° C or higher. Furthermore, a method for recycling the catalyst in the continuous polymerization method (Japanese Patent Publication No. 1-28)
766) is proposed, and in this specification, the first tank is 3
There is an example of 5 ° C. and 20 ° C. or less after the second tank, but the catalyst used does not contain secondary amine.

[0004]

The object of the present invention is to provide an economical method for producing a polyphenylene ether having heat coloring, particularly less yellowness, less nitrogen content causing odor, and a narrow molecular weight distribution. To do.

[0005]

[Means for Solving the Problems] Under these circumstances, the present inventors have conducted diligent research to achieve the above-mentioned object, and as a result, the existence of a catalyst system containing a secondary amine and a transition metal compound has been confirmed. The temperature at the time of oxidatively polymerizing the nuclear-substituted phenols is set to 35 ° C. or higher in the former stage where the heat generation is large until the oxygen consumption reaches 50% or more and less than 80% of the theoretical amount, and the subsequent stage thereafter. It was found that by setting the temperature to less than 35 ° C., it is possible to produce a polyphenylene ether having a low yellow coloration and a low nitrogen content and a narrow molecular weight distribution while maintaining the economic benefits, and thus completed the present invention.

That is, the present invention is the invention described below. (I) General formula (1) R ₁ R ₂ NH (1) (In the formula, R ₁ and R ₂ each independently represent an alkyl group having 1 to 12 carbon atoms, a substituted alkyl group, an alkenyl group or a substituted alkenyl group. .) In the presence of a catalyst containing a secondary amine and a transition metal compound, the polymerization temperature for the oxidative polymerization of the nucleus-substituted phenols with an oxygen-containing gas is such that the oxygen consumption is required for completion of the polymerization. 50% or more for the theoretical oxygen amount 8
A polyphenylene ether having a temperature of 35 ° C. or higher and 100 ° C. or lower until it reaches less than 0% (first stage) and 5 ° C. or higher and lower than 35 ° C. after the oxygen consumption reaches the predetermined amount (second stage). Production method. (II) The method for producing polyphenylene ether according to (I), wherein the polymerization temperature in the first stage is 35 ° C. or higher and 60 ° C. or lower and the polymerization temperature in the second stage is 20 ° C. or higher and lower than 35 ° C. (III) The method for producing a polyphenylene ether according to (I) or (II), wherein the transition metal compound is a manganese compound. (IV) As a catalyst component, at least one basic compound selected from hydroxides, alkoxides or phenoxides of Group IA metals of the periodic table, and hydroxides or oxides of Group IIA metals and the general formula (2) ) R ₃ —NH—R ₄ —OH (2) (In the formula, R ₃ represents hydrogen, an alkyl group having 1 to 12 carbon atoms, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, a phenyl group or a substituted phenyl group. , R ₄ has 2 to 2 carbon atoms
12 represents an alkylene group or a substituted alkylene group. )
The method for producing a polyphenylene ether according to (III), wherein the catalyst further comprises an alkanolamine represented by (V) The alkanolamine is R in the general formula (2).
1 to 12 carbon atoms with ₃ substituted by hydrogen or hydroxy group
( ₄₎ is an alkyl group, and R ₄ is an alkylene group having 2 to 12 carbon atoms. (VI) As a catalyst component, general formula (3) HO—R ₅ —OH (3) [wherein, R ₅ is an alkylene group having 2 to 12 carbon atoms, a substituted alkylene group, — (CH ₂ CH ₂ O) n -CH ₂ CH ₂
-, and _{- [CH (CH 3) CH} 2 O] n-CH (C
H ₃₎ CH ₂ - represents a divalent organic radical selected from the group consisting of. Here, n represents an integer of 1 to 5. ] It is characterized by being a catalyst further containing the diol represented by (I
V) or the method for producing the polyphenylene ether according to (V).

Next, the present invention will be described in detail. The nuclear-substituted phenols used in the present invention have the general formula (4)

Embedded image (In the formula, R ₆ , R ₇ , R ₉ , R ₁₀ and R ₁₁ are each independently hydrogen, halogen, an alkyl group having 1 to 20 carbon atoms, a substituted alkyl group, an alkenyl group, a substituted alkenyl group, an aryl group or a substituted group. R ₈ is an aryl group and R ₈ is hydrogen or a linear alkyl group having 1 to 4 carbon atoms). Preferred nuclear-substituted phenols are 2,6
-Dimethylphenol, 2,6-diethylphenol,
2,6-diallylphenol, 2-ethyl-6-methylphenol, 2-benzyl-6-methylphenol, 2
-Methyl-6- (2-octyl) phenol, 2-allyl-6-methylphenol, 2- (3-hydroxypropyl) -6-methylphenol, 2- (3- [2-aminoethylthio] propyl) -6-methyl Phenol, 2
-Methyl-6-phenylphenol, 2,3,6-trimethylphenol, 2,4,6-trimethylphenol and the like can be mentioned. These can be used alone or in combination of two or more. Particularly preferred nuclear-substituted phenols are 2,6-dimethylphenol, 2,
3,6-trimethylphenol etc. can be mentioned.

The secondary amine which is an essential component of the catalyst used in the present invention is represented by the general formula (1) R ₁ R ₂ NH (1) (wherein R ₁ and R ₂ are as defined above). ) Is a compound represented by. Preferred secondary amines include dimethylamine, diethylamine, di-n-propylamine,
Examples include di-n-butylamine, di (2-methyl-1-propyl) amine, di-n-hexylamine, di-n-octylamine, n-butylmethylamine, di (2-methoxyethyl) amine, diallylamine and the like. Particularly preferred secondary amines are dimethylamine and di-
Examples thereof include n-butylamine.

The secondary amine is used in an amount of preferably 0.001 to 0.1 mol, more preferably 0.005 to 0.05 mol, per mol of the nuclear-substituted phenol used. If the amount used is less than 0.001 mol per mol of the nuclear-substituted phenols, the impact properties of the molded article are unsatisfactory, and if it exceeds 0.1 mol, it is economically disadvantageous and neither is preferred.

The transition metal compound which is an essential component of the catalyst used in the present invention includes transition metal compounds such as manganese, copper and cobalt, and is not particularly limited. A catalyst containing a manganese compound is preferable, and a manganese salt is more preferable as the manganese compound, from the viewpoint that the molecular weight of the polymer can be appropriately controlled when the polymerization temperature in the first stage is set to a relatively high temperature.

The catalyst containing a manganese compound used in the present invention is preferably a catalyst containing (i) a manganese salt, a basic compound and an alkanolamine, and more preferably (ii) a catalyst containing a diol.

The manganese salt used in the present invention is preferably a manganese halide such as manganese chloride or manganese bromide, an inorganic acid such as manganese nitrate, manganese sulfate, manganese carbonate, manganese formate, manganese acetate, manganese oxalate or an organic acid. The manganese salt of an acid etc. are mentioned. These may be used alone or in combination of two or more. Particularly preferred manganese compounds include manganese chloride, manganese bromide, manganese acetate and the like.

The manganese salt is preferably used in an amount of 0.0001 to 0.02 mol, more preferably 0.0002 to 0.01 mol, per mol of the nuclear-substituted phenol. If the usage ratio is less than 0.0001 mol per mol of the nuclear-substituted phenols, the polymerization rate is extremely slow, and if it is more than 0.02 mol, it is difficult to control the molecular weight of the polymer, which is not preferable.

The basic compound used in the present invention is at least one compound selected from hydroxides, alkoxides or phenoxides of Group IA metals of the periodic table, and hydroxides or oxides of Group IIA metals. Is mentioned. Preferred basic compounds include hydroxides of Group IA metals of the periodic table such as lithium hydroxide, sodium hydroxide and potassium hydroxide; hydroxides of Group IIA metals of the periodic table such as calcium hydroxide and magnesium hydroxide. And their oxides; alkoxides of Group IA metals of the periodic table such as sodium methoxide, potassium methoxide, sodium ethoxide, sodium n-propoxide, sodium isopropoxide, sodium t-butoxide; sodium phenoxide, potassium phenoxide, etc. Examples include phenoxides of Group IA metals of the periodic table. Particularly preferred basic compounds include sodium hydroxide, potassium hydroxide and the like. These basic compounds are preferably supplied to the reaction system as they are or in the state of being dissolved in a polar solvent such as alcohol.

The above basic compound is preferably used in an amount of 10 to 1,000 mol, more preferably 50 to 300 mol, per 1 mol of the manganese compound used. If the amount used is less than 10 moles per mole of manganese salt, the polymerization rate is extremely slow, and if it is more than 1,000 moles, it is economically disadvantageous and neither is preferable.

The alkanolamine used in the present invention is represented by the general formula (2) R ₃ --NH--R ₄ --OH (2) (wherein R ₃ and R ₄ are as defined above). Is a compound. R ₃ in the formula is hydrogen, a methyl group,
Examples thereof include ethyl group, propyl group, butyl group, 2-hydroxyethyl group, 3-hydroxypropyl group, 4-hydroxybutyl group, allyl group and phenyl group. Also, R
_{As 4} , ethylene group, propylene group, butylene group,
Examples thereof include 1,2-dimethylethylene group. Preferred alkanolamines include monoethanolamine,
Diethanolamine, N-methylethanolamine, N
-Ethylethanolamine, N-allylethanolamine, N-phenylethanolamine, 3-amino-1-
Propanol, 2-amino-1-propanol, 1-amino-2-propanol, di (2-hydroxy-1-propyl) amine, 4-amino-1-butanol and the like can be mentioned.

A more preferred alkanolamine used in the present invention is that, in the general formula (2), R ₃ represents hydrogen or an alkyl group substituted with a hydroxy group having 1 to 12 carbon atoms, and R ₄ has 2 to 12 carbon atoms. It is a compound showing an alkylene group or a substituted alkylene group. Particularly preferable alkanolamines include monoethanolamine and diethanolamine.

The above alkanolamine is used in a proportion of preferably 10 to 500 mol, more preferably 20 to 200 mol, per mol of the manganese compound used.
If the amount used is less than 10 mol per mol manganese salt, a polymer having a practically sufficient molecular weight cannot be obtained, and if it exceeds 500 mol per mol manganese salt, it is economically disadvantageous. Not preferable.

The diol used in the present invention is a compound represented by the general formula (3) HO—R ₅ —OH (3) (wherein R ₅ is as defined above). Preferred diols include ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, propylene glycol, diethylene glycol,
Triethylene glycol etc. are mentioned. Particularly preferred diols include ethylene glycol and 1,4-butanediol.

The above-mentioned diol is preferably used in a proportion of 0.001 to 0.5 mol, more preferably 0.01 to 0.1 mol, per mol of the nuclear-substituted phenols used. Usage ratio is 0.00 per mol of nuclear-substituted phenols
When it is less than 1 mol, no substantial effect is obtained, and when it is more than 0.5 mol, it is economically disadvantageous and neither is preferable.

Although it is desirable to use an organic solvent in the practice of the present invention, it is not particularly limited as long as it is inert to the nuclear-substituted phenols and is liquid at the reaction temperature. As examples of preferable organic solvents, aromatic hydrocarbons such as benzene, toluene and xylene; chain and cyclic aliphatic hydrocarbons such as heptane and cyclohexane; halogenated hydrocarbons such as chlorobenzene, dichlorobenzene and dichloromethane; Acetonitrile, nitriles such as benzonitrile, methanol, ethanol, n-
Propanol, isopropanol, n-butanol, s
alcohols such as ec-butanol; nitrobenzene;
Examples thereof include sulfolane. These are used alone or as a mixture. A preferred organic solvent is a mixed solvent of aromatic hydrocarbon and alcohol. The concentration of the nuclear-substituted phenol used in the organic solvent is preferably 5 to 35% by weight, more preferably 10 to 25% by weight.
It is used in such a ratio that

The oxygen-containing gas used in the present invention is a gas having an oxygen content of 5 to 100% by volume and includes oxygen alone. Other gases except oxygen are inert gases such as nitrogen, argon and helium. Air can be mentioned as a particularly preferable oxygen-containing gas. The supply rate of the oxygen-containing gas can be arbitrarily selected in consideration of heat removal and the like, but is preferably 10 Nml / min or more as pure oxygen per mol of the charged nucleus-substituted phenols.

In the practice of the present invention, the above-mentioned nuclear-substituted phenols, catalysts and solvents containing secondary amines and transition metal compounds, etc. are polymerized separately, or after a part or all of them is preliminarily mixed and polymerized. It is preferably supplied to a vessel and brought into contact with the oxygen-containing gas under a predetermined pressure. The pressure during the polymerization is selected from normal pressure or pressure up to 20 atm, but pressure up to 20 atm is preferred. It is necessary to bring oxygen into sufficient contact with the reaction mixture, and for this means, for example, gas-liquid contact means such as blowing an oxygen-containing gas into the reaction mixture under strong stirring can be used.
As a polymerization method, either a batch method or a flow method can be adopted.

The polymerization temperature in the first stage of the present invention is 35 ° C.
Or more and 100 ° C or less, preferably 35 ° C or more and 60 ° C
It is the following. Oxidative polymerization of nuclear-substituted phenol is a large exothermic reaction, and most of the exothermic heat is generated in the first stage. In order to maintain the polymerization temperature in the former stage at a temperature lower than 35 ° C., a considerable heat removal capacity is required and the economic profit is significantly impaired, which is not preferable. However, the polymerization temperature of the first stage is 100
If the temperature exceeds ℃, the polymerization does not proceed smoothly, which is not suitable. The polymerization time in the first stage varies depending on selected conditions such as the amount of catalyst, the concentration of the nuclear-substituted phenols and the feed rate of the oxygen-containing gas, but is generally preferably 0.5 to 20 hours.

In the present invention, the temperature of the former stage and the latter stage is switched from 50% to less than 80%, preferably from 60% to 80, relative to the theoretical amount of oxygen required for completing the polymerization.
When it reaches less than%. When the temperature switching time is 80% or more, the yellow coloring of the polymer and the reduction of the nitrogen content are not sufficiently achieved, and when the temperature is switched below 80%, the yellow coloring and the nitrogen content are small and a polymer having a narrow molecular weight distribution is obtained. To be However, the temperature switching timing is 50
When it is less than%, the burden of heat removal is increased and the economic profit is greatly reduced, which is not preferable. That is, by switching the temperatures of the former stage and the latter stage in the present invention, the quality of the obtained polymer and the economical efficiency in the production are preferably achieved in a well-balanced manner.

The polymerization temperature in the latter stage of the present invention is 5 ° C. or higher and lower than 35 ° C., preferably 20 ° C. or higher and lower than 35 ° C. If the polymerization temperature in the latter stage is 35 ° C. or higher, the yellow coloring and nitrogen content, which are the objects of the present invention, cannot be sufficiently achieved, which is not preferable. However, when the polymerization temperature in the latter stage is lower than 5 ° C., the reaction does not substantially proceed or is extremely slow and unsuitable. The polymerization time in the latter stage varies depending on the selected conditions such as the amount of catalyst, the concentration of the nuclear-substituted phenols and the supply rate of the oxygen-containing gas, but is generally 0.5 to 20 hours.

After the reaction for a predetermined time, the produced polyphenylene ether is obtained as a reaction mixture on a solution dissolved in a polymerization solvent or a slurry-like reaction mixture free-dispersed in a solid state. Various known methods can be adopted as a post-treatment method for taking out polyphenylene ether as a final product from the reaction mixture. For example, after treating the reaction mixture with an acid such as hydrochloric acid or acetic acid to deactivate the catalyst in the system, it is contacted with a poor solvent for polyphenylene ether such as alcohol, and the resulting slurry is subjected to solid-liquid separation, washing and drying. Method of subjecting the reaction mixture to EDTA
By treating with water containing a chelating agent such as and / or a reducing agent such as sodium pyrophosphate, sodium hydrosulfite, etc., and then performing liquid separation, and distilling off the organic solvent in the organic phase after separation by steam stripping. Examples thereof include a method of obtaining a water-dispersed slurry and subjecting it to solid-liquid separation and drying. For solid-liquid separation, a general-purpose solid-liquid separation means such as a centrifuge, a super decanter, or a vacuum filter can be used. For drying, a usual drying means such as a vacuum dryer, a rotary dryer, a paddle dryer and a flow dryer can be used.

[0028]

The present invention will be described in more detail below with reference to examples, but the scope of the present invention is not limited by these examples.

Reduced viscosity of polyphenylene ether (η
_{SP / C} ): Concentration of polyphenylene ether is 0.5g / d
It is the value measured at 25 ° C. for the chloroform solution of 1. Polyphenylene ether molecular weight distribution (Mw /
Mn): Weight average molecular weight (Mw) and number average molecular weight (Mn) as standard polystyrene conversion values were measured by gel permeation chromatography using RI-8011 manufactured by Tosoh Corporation as a detector, and their ratio (Mw / M
n) was used as a standard for the molecular weight distribution. Nitrogen content in polyphenylene ether (hereinafter sometimes referred to as TN): It is a value measured by Sumigraph NC-90A manufactured by Sumika Chemical Analysis Service. Yellowness of polyphenylene ether molding (hereinafter sometimes referred to as Y.I.): The polyphenylene ether powder was placed in a mold having a thickness of 1 mm, and was set to 250.
Press-molding was performed at 10 ° C. and 10-100 kg / cm ² for 10 minutes, and the obtained 1 mm-thick press sheet was measured for transmission color with a color difference meter Z-1001DP manufactured by Nippon Denshoku Industries Co., Ltd. , Z values calculated by the following equation were evaluated by the yellow index (JIS K7103).

## EQU00001 ## Y. I. = 100 (1.28X-1.06Z) / Y where Y. I. Indicates that the smaller the value, the less the yellow coloring.

Example 1 In a jacketed autoclave with a capacity of 1 liter, equipped with a stirrer, a thermometer, a condenser and an air inlet tube reaching the bottom of the autoclave, 214 g of xylene, 60 g of methanol, 73.3 g of 2,6-dimethylphenol.
(0.60 mol) and sodium hydroxide 1.92 g
(48 mmol) was charged to make a uniform solution, and then 1.32 g (21.6 mmol) of monoethanolamine, 1.49 g (24 mmol) of ethylene glycol and di-n-butylamine (abbreviated as DBA) were added to the solution. 0.7
8 g (6 mmol) and manganese chloride tetrahydrate 5
3.4 mg (0.27 mmol) of methanol 19.2
The solution dissolved in g was added. Then, the reaction pressure is 6 kg
/ Cm2, while vigorously stirring the contents at 950 rpm, add air to this for 400 to 3 hours until 0 to 3 hours.
/ Min / mol at 70N for 3 to 6 hours
Blowing was performed at a speed of ml / min / mol. The polymerization temperature in the first stage was maintained at 40 ° C, the temperature was lowered from 40 ° C to 30 ° C when the oxygen consumption reached 78% of the theoretical consumption, and the polymerization temperature in the second stage was maintained at 30 ° C. The air supply was stopped 6 hours after the start of the air blowing. 60 g of the reaction mixture was taken out, 28 g of methanol was added, the precipitated polymer was suction filtered, and then 2 ml with 100 ml of methanol.
It was washed twice and suction filtered. The obtained polymer was dispersed in a solution prepared by dissolving 0.29 g of sodium pyrophosphate and 0.19 g of sodium hydrosulfite in 50 ml of ion-exchanged water, and treated at 80 ° C. for 10 minutes with stirring. The polymer obtained by suction filtration was washed with 200 ml of deionized water to obtain 2
It was washed twice and suction filtered. The wet polymer was dried under reduced pressure at 150 ° C. for 5 hours to obtain 11.1 g of powdery polyphenylene ether. The results are shown in Table 1.

Examples 2 to 4 and Comparative Examples 1 to 6, except that the presence or absence of DBA in the manganese-based catalyst, the pre-stage polymerization temperature, the post-stage polymerization temperature and the oxygen consumption amount at the time of temperature change were changed as shown in Table 1. The procedure of Example 1 was repeated to obtain polyphenylene ether. The results are shown in Table 1. As shown in Comparative Example 6, it is easy to estimate the effect of the present invention on the quality of polyphenylene ether that the nitrogen content is reduced but the yellow coloring is greatly increased by simply reducing the amount of the secondary amine. Was difficult.

Example 5 A copper catalyst system described in JP-A-59-140225 was referred to. 400 g of toluene in a 1 liter jacketed autoclave equipped with a stirrer, thermometer, condenser and air introduction tube that reaches the bottom of the autoclave.
And 2,6-dimethylphenol 73.3 g (0.6
(0 mol) to prepare a uniform solution, and then add N, N'to the solution.
-Di-t-butylethylenediamine 0.40 g (2.4
Mmol), 3.20 g of n-butyldimethylamine (3
2 mmol) and 1.30 g (10 mmol) of di-n-butylamine (abbreviated as DBA) in toluene 73.7.
56.0 mg (0.39 cuprous oxide)
A solution of 48 mmole hydrogen bromide in 0.64 g and 2.40 g of sodium bromide were added. Then, the reaction pressure was kept at 6 kg / cm ² , and the contents were 950 rpm.
While vigorously stirring, air was blown into this at a rate of 400 Nml / min / mol from 0 to 3 hours and at a rate of 70 Nml / min / mol from 3 to 6 hours. The polymerization temperature of the first stage was maintained at 40 ° C, and when the oxygen consumption reached 75% of the theoretical consumption, 40 ° C to 30 ° C was reached.
The temperature was lowered to ℃, and the polymerization temperature in the latter stage was kept at 30 ℃. The air supply was stopped 6 hours after the start of the air blowing. 60 g of the reaction mixture was extracted and 28 g of methanol
Was added, and the precipitated polymer was suction filtered, washed twice with 100 ml of methanol, and suction filtered. The polymer obtained was treated with sodium pyrophosphate (0.29 g) and sodium hydrosulfite (0.19 g) in deionized water (50 ml).
It was dispersed in a solution dissolved in and was treated at 80 ° C. for 10 minutes under stirring. The polymer obtained by suction filtration was washed twice with 200 ml of deionized water and suction filtered. The wet polymer was dried under reduced pressure at 150 ° C. for 5 hours to obtain 11.1 g of powdery polyphenylene ether. The press molding temperature was 280 ° C. The results are shown in Table 1.

Comparative Example 7 A polyphenylene ether was obtained in the same manner as in Example 5 except that the temperature was not switched. The results are shown in Table 1.

[0034]

[Table 1]

[0035]

INDUSTRIAL APPLICABILITY According to the method for producing polyphenylene ether of the present invention, it is possible to obtain polyphenylene ether of excellent quality in which heat coloring, particularly yellowness is small, the nitrogen content causing odor is small, and the molecular weight distribution is narrow. At the same time, the burden of heat removal is greatly reduced, and in the case of a manganese catalyst system, it has a large economic merit that the polymer molecular weight is maximized under the same catalyst amount.
Its industrial value is enormous. Further, the narrowed molecular weight distribution of polyphenylene ether can be expected to improve the mechanical properties of the molded product.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryuhei Matsui 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co., Ltd. Yokkaichi Research Institute (72) Inventor Shigeki Kiriyama 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Chemical Co. Company Yokkaichi Research Institute

Claims (6)

[Claims] 1. General formula (1) R ₁ R ₂ NH (1) (In the formula, R ₁ and R ₂ are each independently an alkyl group having 1 to 12 carbon atoms, a substituted alkyl group, an alkenyl group or a substituted alkenyl group. In the presence of a catalyst containing a secondary amine and a transition metal compound represented by the formula (3), the polymerization temperature at the time of oxidatively polymerizing the nucleus-substituted phenols with an oxygen-containing gas, the oxygen consumption is 50% or more of the theoretical amount of oxygen required for
A polyphenylene ether having a temperature of 35 ° C. or higher and 100 ° C. or lower until it reaches less than 0% (first stage) and 5 ° C. or higher and lower than 35 ° C. after the oxygen consumption reaches the predetermined amount (second stage). Production method. 2. The method for producing a polyphenylene ether according to claim 1, wherein the polymerization temperature in the first stage is 35 ° C. or higher and 60 ° C. or lower, and the polymerization temperature in the second stage is 20 ° C. or higher and lower than 35 ° C. 3. The method for producing a polyphenylene ether according to claim 1, wherein the transition metal compound is a manganese compound. 4. A hydroxide, alkoxide or phenoxide of a Group IA metal of the periodic table, IIA as a catalyst component.
At least one basic compound selected from hydroxides or oxides of group metals and the general formula (2) R ₃ —NH—R ₄ —OH (2) (wherein R ₃ is hydrogen and the number of carbon atoms is 1). To 12 alkyl groups, substituted alkyl groups, alkenyl groups, substituted alkenyl groups, phenyl groups or substituted phenyl groups, R ₄ has 2 to 2 carbon atoms.
12 represents an alkylene group or a substituted alkylene group. )
The method for producing a polyphenylene ether according to claim 3, wherein the catalyst further comprises an alkanolamine represented by: 5. The alkanolamine has a carbon number of 1 in which R ₃ is hydrogen or a hydroxy group in the general formula (2).
To 12 alkyl groups, and R ₄ is an alkylene group having 2 to 12 carbon atoms. 5. The method for producing polyphenylene ether according to claim ₄ , wherein R ₄ is an alkylene group having 2 to 12 carbon atoms. 6. A catalyst component of the general formula (3) HO—R ₅ —OH (3) [wherein R ₅ is an alkylene group having 2 to 12 carbon atoms, a substituted alkylene group, or — (CH ₂ CH ₂ O). ) N-CH ₂ CH ₂
-, and _{- [CH (CH 3) CH} 2 O] n-CH (C
H ₃₎ CH ₂ - represents a divalent organic radical selected from the group consisting of. Here, n represents an integer of 1 to 5. ] The manufacturing method of polyphenylene ether of Claim 4 or 5 which is a catalyst which further contains the diol represented by these.