JPH0832779B2 - Method for producing polyphenylene oxide - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for producing polyphenylene oxide. More specifically, it relates to a method for producing a polyphenylene oxide of good quality by oxidatively polymerizing a nuclear-substituted phenol by using a catalyst containing a manganese compound, a basic compound, alkanolamines diols and amines.

<Prior Art> Polyphenylene oxide obtained by oxidative polymerization of nuclear-substituted phenol is known to be a useful resin, and a polymer alloy of polyphenylene oxide and polystyrene or polyamide has excellent thermal properties, mechanical properties, and electrical properties. In recent years, it has been widely applied as a molding material to various fields.

Conventionally, various methods for producing such polyphenylene oxide by oxidatively polymerizing a nucleus-substituted phenol are known, and a copper compound, a manganese compound or a cobalt compound is combined with a ligand selected from various amines and bases. The method using the above catalyst system is common, and there are many proposals relating to these. Among them, a catalyst system in which a manganese compound and a basic compound such as sodium hydroxide are combined (Japanese Patent Publication No. 45-30354) is economical and highly active, and is a system of interest. However, this system cannot control the molecular weight of the obtained polyphenylene oxide,
There is a problem that the obtained polyphenylene oxide has a poor quality such as gelation at the time of heating and melting, and as a method for solving such a problem, the present inventors previously mentioned that monoethanolamine and / or diethanolamine were used. A method using a catalyst system in which a manganese compound and a basic compound are combined has been proposed (JP-A-57-44625).
Recently, a method of using N-alkylalkanolamine in place of the above monoethanolamine and / or diethanolamine has also been proposed (JP-A-60-8318).

<Problems to be Solved by the Invention> However, the polyphenylene oxide obtained by these methods solves the above-mentioned problems of controlling the molecular weight and gelation at the time of heating and melting, but the problem of coloring during heating and melting (heat coloring ), The application range is limited as compared with other colorless engineering plastics such as polycarbonate, and the quality cannot be said to be sufficiently satisfactory.

It is an object of the present invention to provide a method for producing an excellent polyphenylene oxide with less heat coloring.

<Means for Solving Problems> Under the circumstances as described above, the present inventors have found that polyphenylene oxide based on a catalyst system comprising a combination of an economically profitable manganese compound and a basic compound. As a result of earnest research to establish a method for obtaining an excellent polyphenylene oxide with little heat coloring in the production method of the above, a specific alkanolamine and a specific diol were identified as a specific manganese compound and a basic compound. The inventors have found that when a catalyst system in which the above-mentioned amines are simultaneously combined is used, the thermal coloring is remarkably improved, and the present invention has been completed.

That is, the present invention is a method for producing polyphenylene oxide by oxidatively polymerizing a nuclear-substituted phenol with an oxygen-containing gas in an organic solvent in the presence of a catalyst, wherein one or more divalent manganese salts are used as the catalyst. Manganese compounds containing, Group IA metal hydroxides,
Alkoxides and phenoxides, and at least one basic compound selected from the group consisting of hydroxides and oxides of Group IIA metals, a general formula [I] R ¹ —NH—R ² —OH [I] ( In the formula, R ¹ represents hydrogen or an alkyl group having 1 to 12 carbon atoms which may have a hydroxyl group as a substituent, and R ² represents an alkylene group having 2 to 12 carbon atoms.). alkanolamines, and formula (II) in HO-R ³ -OH (II) (wherein, R ³ is an alkylene group having 1 to 12 carbon _{atoms, CH 2 CH 2 O n CH} 2 CH 2 -, and A divalent organic group selected from the group consisting of:

Here, n represents an integer of 1 to 5. ) And a general formula [III] R ⁴ R ⁵ NH [III] (wherein R ⁴ and R ⁵ are hydrogen, an alkyl group having 1 to 24 carbon atoms or an aralkyl having 7 to 24 carbon atoms) Group, provided that R ⁴ and
It does not include those in which R ⁵ is both hydrogen, and also include those in which R ⁴ and R ⁵ are joined to form a ring. ) The catalyst system containing amines represented by
0.1 mol, the diols are 0.02 to 0.1 mol,
The present invention provides a method for producing polyphenylene oxide, characterized in that the amount of the amines is 0.005 to 0.05 mol.

The nuclear-substituted phenols used in the present invention have the general formula (In the formula, R ₁ , R ₂ , R ₃ , R ₄ and R ₅ are any of hydrogen, halogen, a hydrocarbon group, a cyano group, a hydrocarbononoxy group or a substituted hydrocarbononoxy group, At least one is hydrogen, and at least one is other than hydrogen.) Specific examples include 2-methylphenol, 3-methylphenol, 2-ethylphenol, and 2 -Methyl-6-benzylphenol, 2,6-dimethylphenol, 2-methyl-6-ethylphenol, 3-methyl-6-t-butylphenol, 2,6-diallylphenol, 2,6-diphenylphenol, 2, 6-dichlorophenol, 2,6-dibromophenol, 2,6-dimethoxyphenol, 4-cyanophenol, 2,3,6-trimethylphenol, 2,4-dimethyl-3-chlorophenol Etc. The. 2,6-dimethylphenol as a preferred substituted phenol,
2,3,6-trimethylphenol and the like can be mentioned. These can be used alone or in combination.

As the manganese compound used in the present invention,
Manganese halides such as manganese chloride and manganese bromide,
Manganese salts of inorganic or organic acids such as manganese nitrate, manganese sulfate, manganese carbonate, manganese formate, manganese acetate, manganese oxalate, manganese naphthenate, manganese salts such as sodium manganate, potassium permanganate, permanganate Permanganates such as calcium, manganese hydroxide, manganese oxide and the like can be mentioned. These may be preferably used in the form of anhydrides or hydrates. Preferred manganese compounds include manganese chloride, manganese bromide, manganese acetate and the like.

One feature of the present invention is that oxidative polymerization proceeds by using an extremely small amount of a manganese compound. In carrying out the present invention, the manganese compound is used in an amount of 0.0001 mol or more, preferably 1 mol or more, per mol of the nuclear-substituted phenols. It may be used in an amount of 0.0002 mol or more. When the amount used is less than 0.0001 mol per mol of the nuclear-substituted phenols, the oxidative polymerization does not substantially proceed or is extremely slow, which is not preferable. However, there is no particular limitation on the side that uses a large amount.

Examples of the basic compound used in the present invention include lithium hydroxide, sodium hydroxide, potassium hydroxide and other metals of Group IA of the periodic table, and metal hydroxides such as calcium hydroxide and magnesium hydroxide of Group IIA of the periodic table. And their oxides, sodium methoxide, potassium methoxide, sodium ethoxide, sodium-n-propoxide, sodium-iso-propoxoxide, potassium-t.
-Alkoxides of metals of Group IA of the periodic table, such as butoxide,
Examples include phenoxides of Group IA metals of the periodic table such as sodium phenoxide and potassium phenoxide. Of these, sodium hydroxide and potassium hydroxide are particularly preferable. These basic compounds are supplied to the reaction system as they are or in the state of being dissolved in a polar solvent such as alcohol.

In carrying out the present invention, the basic compound is used in an amount of 10 to 1,000 mol, preferably 50 mol, per mol of the manganese compound used.
Used in proportions of ~ 200 mol. When the amount used is less than 10 mol per mol of the manganese compound, the polymerization rate is extremely slow, and when it is more than 1,000 mol, the effect is the same as the case of less than that and it is uneconomical, which is not preferable.

The object of the present invention to obtain an excellent quality of polyphenylene oxide is, for the first time, the simultaneous use of specific alkanolamines, specific diols and specific amines in addition to the above-mentioned manganese compound and basic compound. What is achieved here is that the specific alkanolamines herein are alkanolamines in which the amino group represented by the above general formula [I] is a primary or secondary amino group. Specific examples of R ^{1 in} the formula include hydrogen, methyl group, ethyl group, propyl group, butyl group, 2-
A hydroxyethyl group etc. can be mentioned. Also, R ²
Specific examples thereof include ethylene group, propylene group and butylene group. Specific examples of such alkanolamines include monoethanolamine, N-methylethanolamine, N-ethylethanolamine, iso-propanolamine, iso-butanolamine, diethanolamine and the like. Among these, preferable alkanolamines include monoethanolamine and diethanolamine.

In the present invention, the above-mentioned alkanolamines exert an action of promoting oxidative polymerization in a specific range of use ratio with respect to the nucleus-substituted phenols, and play the role of catalytic action. That is, in the practice of the present invention, the alkanolamines are used in a proportion of 0.01 to 0.1 mol per mol of the nuclear-substituted phenols used. If the usage ratio is less than 0.01 mol or more than 0.1 mol per mol of the nuclear-substituted phenols, it is not preferable because a polyphenylene oxide having a practical molecular weight cannot be obtained.

The specific diols are compounds represented by the general formula [II], and specific examples thereof include ethylene glycol, trimethylene glycol, 1,4-butanediol, 1,6-hexanediol, 1,8-octanediol, diethylene glycol, triethylene glycol and the like can be mentioned. Preferred glycols are ethylene glycol and 1,4-butanediol.

In the practice of the present invention, the above glycols are used in a proportion of 0.02 to 0.1 mol per mol of the nuclear-substituted phenol used. If the usage ratio is less than 0.02 mol per mol of the nuclear-substituted phenol, no substantial effect can be obtained, and the amount is less than 0.
If it is more than 1 mol, it is simply uneconomical and both are not preferable.

In the present invention, specific amines are used in addition to the above constituent components of the catalyst. This gives a polyphenylene oxide having improved mechanical properties as well as improved thermal coloring. Such amines are represented by the general formula [III] R ⁴ R ⁵ NH [III] (wherein R ⁴ and R ⁵ represent hydrogen, an alkyl group having 1 to 24 carbon atoms or an aralkyl group having 7 to 24 carbon atoms). However, R ⁴
Does not include those in which R ⁵ and R ⁵ are both hydrogen, and those in which R ⁴ and R ⁵ are joined to form a ring. ) Is a primary or secondary amine. General formula (II
Examples of amines represented by I] include n-propylamine, iso-propylamine, n-butylamine, iso-butylamine, sec-butylamine, n-hexylamine, n-octylamine, 2-ethylhexylamine,
Primary amines such as cyclohexylamine, laurylamine and benzylamine, and diethylamine, di-n-propylamine, di-n-butylamine, di-iso-butylamine, di-n-octylamine, piperidine, 2-
Specific examples include secondary amines such as pipecoline.

Particularly preferred amines include secondary amines such as di-n-butylamine and piperidine.

When such amines are used in the practice of the present invention, the amount used is based on 1 mol of the nuclear-substituted phenol used.
It is 0.005 to 0.05 mol.

The organic solvent used in the present invention is not particularly limited as long as it is inert to the nuclear-substituted phenols and is liquid at the reaction temperature. Preferred examples include aromatic hydrocarbons such as benzene, toluene and xylene, chain and cyclic aliphatic hydrocarbons such as heptane and cyclohexane, chlorobenzene and dichlorobenzene,
Halogenated hydrocarbon such as dichloromethane, dioxane,
Ethers such as diethyl ether, cyclohexanone,
Ketones such as acetophenone, esters such as ethyl acetate and propiolactone, nitriles such as acetonitrile and benzonitrile, methanol, enol, n-
Propanol, isopropanol, n-butanol, se
Examples thereof include alcohols such as c-butanol, nitrobenzene, and sulfolane. These are used alone or as a mixture. Preferred organic solvents are mixed solvents of aromatic hydrocarbons and alcohols, and particularly preferred are toluene / methanol, toluene / ethanol, toluene / n-propanol, toluene /
Isopropanol, xylene / methanol, xylene /
A mixed solvent of ethanol, xylene / n-propanol, xylene / isopropanol and the like can be mentioned.

In the practice of the present invention, the organic solvent has a concentration of the nuclear-substituted phenols of 5 to 35% by weight, preferably 10 to
It is used in a proportion of 25% by weight. If the concentration is out of this range, a polyphenylene oxide having a practical molecular weight cannot be obtained, which is not preferable.

The oxygen-containing gas used in the present invention includes oxygen alone or an oxygen-containing gas such as air.

Thus, in carrying out the present invention, the above-mentioned nuclear-substituted phenols, manganese compounds, basic compounds, alkanolamines, diols, solvents and amines are each separately or premixed with some or all of them. After that, it is supplied to the reactor and brought into contact with the oxygen-containing gas under a predetermined reaction temperature and pressure. The supply rate of the oxygen-containing gas to the reaction system can be arbitrarily selected in consideration of heat removal and the like, but usually 10 Nml / min or more is adopted as pure oxygen per mol of the charged nucleus-substituted phenols. It is necessary to bring oxygen into sufficient contact with the reaction mixture, and as a means for this, for example, a conventional gas-liquid contact means such as blowing an oxygen-containing gas into the reaction mixture under strong stirring can be used. . As a reaction system, either a batch system or a flow system can be adopted. The reaction temperature is selected within a range in which the reaction system is kept liquid and a smooth reaction proceeds, and is usually 0 to 100.
C, preferably 10 to 60C.

If the reaction temperature is lower than 0 ° C, the polymerization rate is slow, so
If the temperature is higher than 100 ° C, the polymerization hardly progresses.
Both are not preferable. The pressure during the reaction can be arbitrarily selected according to the purpose and is not particularly limited, but normal pressure or pressurization up to about 20 atm is preferably selected. The reaction time varies depending on the selected conditions such as the amount of the catalyst, the concentration of the nuclear-substituted phenols or the supply rate of the oxygen-containing gas, but is generally 0.5.
-20 hours is preferably selected.

After the reaction for a predetermined time, the produced polyphenylene oxide is obtained as a reaction mixture in the form of a solution dissolved in a polymerization solvent, or a reaction mixture in the form of a slurry that is solid and free-dispersed. Various methods can be adopted as a post-treatment method for taking out polyphenylene oxide 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 in order to deactivate the catalyst in the system, it is contacted with a non-solvent for polyphenylene oxide such as alcohol, and the resulting slurry is subjected to solid-liquid separation, washing and drying. Method, the reaction mixture is treated with water containing a chelating agent such as EDTA, sodium pyrophosphate and / or a reducing agent such as hydrosulfite, then liquid separation, and the organic solvent in the organic phase after liquid separation is removed. A method in which a water-dispersed slurry is obtained by distilling off by steam stripping, and then subjected to solid-liquid separation and drying can be mentioned. For solid-liquid separation, a conventional solid-liquid separation means such as a centrifuge, a decanter, or a vacuum filter is used. For drying, a usual device such as a vacuum dryer, a rotary dryer, a paddle dryer and a flow dryer can be used.

<Examples> Hereinafter, the present invention will be described in more detail with reference to Examples, but the scope of the present invention is not limited by these Examples.

In addition, the reduced viscosity (ηsp / C) of polyphenylene oxide in the examples indicates that the concentration of polyphenylene oxide is
It is a value measured at 25 ° C. for a chloroform solution of 0.5 g / dl. Regarding the degree of heat coloring, the polyphenylene oxide powder was put in a mold and compression-molded at 250 ° C / 100kg / cm ² for 10 minutes. The press sheet with a thickness of 1 mm obtained was manufactured by Nippon Denshoku Industries Co., Ltd. -Transparent color is measured with -101DP type,
The whiteness (W value) calculated from the obtained Lab value according to the following equation was evaluated.

Here, the larger the W value, the less the thermal coloring is.

Comparative Example 1 In a jacketed autoclave with a capacity of 10 liter, equipped with a stirrer, a thermometer, a condenser, and an air introduction tube reaching the bottom of the autoclave, xylene 3,570 g, methanol 1,
After 220 g, 2,6-dimethylphenol 1,222 g (10 mol) and sodium hydroxide 32 g (0.8 mol) were charged into a uniform solution, 24.4 g (0.4
Mol), ethylene glycol 24.8 g (0.4 mol) and manganese chloride tetrahydrate 0.99 g (0.005 mol) in methanol 10
A solution dissolved in 0 g was added. Then, the contents were vigorously stirred and air was blown into this at a speed of 1 / min. Reaction temperature and pressure are 35 ℃ and 6kg / cm ² respectively.
Maintained at. 12 hours after the start of blowing air, the air supply was stopped and the reaction mixture was charged with methanol 2250
thrown in g. The precipitated polyphenylene oxide was separated with a centrifuge, washed once with 2400 g of methanol, separated again, and then dispersed in an aqueous solution prepared by dissolving 28 g of sodium pyrophosphate and 19 g of sodium hydrosulfite in 4.8 l of water and stirring conditions. Heated down and treated at 80 ° C. for 1 hour. The polyphenylene oxide separated by the centrifuge was washed twice with 5 l of water, then centrifuged and dried under reduced pressure at 150 ° C. overnight. As a result, powdered polyphenylene oxide
1140 g were obtained. The polyphenylene oxide thus obtained had a whiteness (W value) of 68. First
The reduced viscosity and W value are shown in the table.

Examples 1 to 8 and Comparative Examples 2 to 10 Polyphenylene oxide was prepared in the same manner as in Comparative Example 1 except that the kinds and amounts of alkanolamines, diols and amines were changed as shown in Tables 1 and 2. Obtained. However, in Comparative Example 10, sodium hydroxide was not added. The reduced viscosity and W value of the obtained polyphenylene oxide are shown in Tables 1 and 2.

<Effects of the Invention> According to the present invention described in detail above, particularly in the production of colored resin products, there are advantages such as i) a wide range of color tones to be selected, ii) economical use with a small amount of pigment used, and the like. An excellent quality polyphenylene oxide with little heat coloring can be obtained economically, and its industrial value is enormous.

 ─────────────────────────────────────────────────── ─── Continuation of front page (72) Inventor Ryuhei Matsui 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. Resin Research Laboratory (72) Inventor Shigeki Kiriyama 1 Toho-cho, Yokkaichi-shi, Mie Mitsubishi Petrochemical Co., Ltd. (56) Reference JP 62-240322 (JP, A) JP 57-44625 (JP, A) JP 60-8318 (JP, A) JP 62-185711 ( JP, A) JP 63-54424 (JP, A) JP 47-36518 (JP, B1)

Claims (2)

[Claims] 1. A method for producing a polyphenylene oxide by oxidatively polymerizing a nuclear-substituted phenol with an oxygen-containing gas in an organic solvent in the presence of a catalyst, the catalyst comprising:
Selected from the group consisting of manganese compounds containing one or more divalent manganese salts, hydroxides of Group IA metals, alkoxides and phenoxides, and hydroxides and oxides of Group IIA metals. At least one basic compound represented by the general formula [I] R ¹ —NH—R ² —OH [I] (wherein R ¹ is hydrogen or the number of carbon atoms which may have a hydroxyl group as a substituent). 1 to 12 alkyl groups, R ² represents an alkylene group having 2 to 12 carbon atoms, and an alkanolamine represented by the general formula [II] HO-R ³ -OH [II] (wherein , R ³ is an alkylene group having 2 to 12 carbon _{atoms, CH 2 CH 2 O n CH} 2 CH 2 -, and A divalent organic group selected from the group consisting of: Here, n represents an integer of 1 to 5. ) And a general formula [III] R ⁴ R ⁵ NH [III] (wherein R ⁴ and R ⁵ are hydrogen, an alkyl group having 1 to 24 carbon atoms or an aralkyl having 7 to 24 carbon atoms) Group, provided that R ⁴ and
It does not include those in which R ⁵ is both hydrogen, and also include those in which R ⁴ and R ⁵ are joined to form a ring. ) The catalyst system containing amines represented by
0.1 mol, the diols are 0.02 to 0.1 mol,
The method for producing polyphenylene oxide, wherein the amines are 0.005 to 0.05 mol. 2. The diols are ethylene glycol and / or
Alternatively, it is 1,4-butanediol.
A method for producing the polyphenylene oxide according to the item.