JPS62158720A - Polymerization of polyphenylene ether - Google Patents

Abstract

PURPOSE:To obtain the titled compound of excellent quality economically in good yields, by contacting a phenol with an oxygen-containing gas in the presence of a specified catalyst in a basic reaction medium. CONSTITUTION:A phenol (A) unsubstituted in position para to the hydroxyl group of the formula [wherein R1-4 are each H, a halogen, a hydrocarbon(oxy) or a halohydrocarbon and it is preferable that these hydrocarbon groups or hydrocarbon moieties have no tertiary alpha-hydrocarbon group] is oxidatively polymerized with an oxygen-containing gas (B) (e.g., air) at 0-80 deg.C in the presence of a catalyst (C) comprising at least 0.05mol, per mol of component A, of a cobalt compound (a) (e.g., CoCl2.6H2O) and 0.5-20mol, per mol of component (a), of an alkanolamine (b) (e.g., triethanolamine) in a basic reaction medium (D) (e.g., methanol in which NaOH is dissolved).

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial Application Field> The present invention relates to a method for producing polyphenylene ether. More specifically, the present invention uses phenols unsubstituted at the para position to the hydroxyl group as raw materials and uses a highly active catalyst system to produce polyphenylene ether of excellent quality in good yield and economically. It relates to a manufacturing method.

<Prior art> Conventionally, oxidized polymers of phenols unsubstituted at the para position have been known as polyphenylene ethers, which have excellent mechanical properties, electrical properties, heat resistance, etc., and have low water absorption. Due to its properties such as good dimensional stability, it has recently attracted attention as a thermoplastic engineering glass.

By the way, several polymerization methods are known in which a cobalt compound is used as a catalyst when producing polyphenylene ether by oxidative polymerization of phenols. For example, cobalt compounds and alkali metal hydroxides, alkoxides,
A method of polymerizing phenols in the presence of a basic compound such as phenoxyte (Japanese Patent Publication No. 33432/1983)
, a method of polymerizing phenols in the presence of a complex consisting of a cobalt salt and an amine (Japanese Patent Publication No. 42-4673)
etc. have been proposed.

<Problems to be Solved by the Invention> However, in all of these methods, the catalytic activity is low, and the cobalt compound used is extremely large, ranging from 1 to 50 mol per 7 enols. Therefore, not only does the cost of the catalyst increase, but the process for removing the residual solvent from the produced polymer becomes complicated, and removal of the catalyst also requires a large amount of cost. Furthermore, since the catalyst in the polymer cannot be completely removed, the quality of the polymer inevitably deteriorates due to residual catalyst.

<Means for Solving the Problems> Under these circumstances, the present inventors used a highly active catalyst that requires only a small amount of cobalt compound to eliminate the para position relative to the hydroxyl group. With the aim of providing an economically advantageous method for producing high-quality polyphenylene ether through direct oxidative polymerization of phenols, we have conducted extensive research and found that a cobalt compound and an alkanolamine were used as catalysts. The inventors discovered that the above object could be achieved by oxidative polymerization of the phenol in a basic reaction medium using a catalyst of the present invention, and based on this knowledge, the present invention was completed.

That is, the present invention is characterized in that hepta-enols unsubstituted at the para-position relative to the hydroxyl group are brought into contact with an oxygen-containing gas in the presence of a catalyst consisting of a cobalt compound and an alkanolamine in a basic reaction medium. The present invention provides a method for polymerizing polyphenylene ether.

The phenols used in the method of the present invention are unsubstituted phenol derivatives at the para-position relative to the hydroxyl group, represented by: R□, R2, R1 and R4 in general formula (1) are a hydrogen atom, a halogen atom, a hydrocarbon group, a halohydrocarbon group or a hydrocarbonoxy group, and they may be the same or different, Moreover, it is preferable that the hydrocarbon group or hydrocarbon moiety does not have a tertiary-α-hydrocarbon. Examples of such phenols include 2,6-
dimethylphenol, 2-methyl-6-nitylphenol, 2,6-dinitylphenol, 2-methyl-6-n
-Propylphenol, 2-methyl-6-is.

-propylphenol, 2-methyl-6-medoxyphenol, 2.6-simethoxyphenol, 216-diphenylphenol, 2,3.6-)limethylphenol, 2,3,5.6-titramethylphenol, 2, s-
c) f-3-chlorophenol, 0-/resol, and the like. These may be used alone or in combination of two or more.

The cobalt compounds used in the method of the present invention include divalent,
Any trivalent compound can be used. Examples of divalent cobalt compounds include copal chloride)
(I[), copal bromide) (II), fval iodide) (II), a(R copal) (II), copal nitrate) (I[), copal phosphate) (II),
cobal acetate) (II), copal chelate) (I[),
cobalt benzoate (II), cobalt naphthenate (I)
I), fuvalt stearate (■), kohal) (I
[) Acetylacetonate, cobaltocene, etc. and their water products; Copal as a trivalent cobalt compound)
(III) Acetylacetonate and the like and hydrates thereof can be mentioned.

The amount of the cobalt compound to be used is usually 0.05 mole or more, preferably 0.05 mole or more based on the phenol. lO
-2 molt. If the amount used is less than 0.05 mole, the effect as a catalyst will not be sufficiently exhibited, and if it exceeds 2 mole, the rate of phenylene ether formation will increase, making it difficult to control the molecular weight. It becomes difficult to remove.

The alkanolamines used in the method of the present invention include:
Primary, secondary and tertiary alkanolamines are used.

Examples of primary alkanolamines include ethanolamine/, 2-hydroxyethylamine/, 3-hydroxyglobylamine, 2-phenylethanolamine, and 3-hydroxy-2-aminobutane.

Examples of secondary alkanolamines include jetanolamine, di-l-propanolamine, bis(2-phenyl-2-hydroxyethyl)amine, and the like.

Examples of tertiary alkanolamines include triethanolamine, tri-l-propanolamine, tris(2
-phenyl-2-hydroxyethyl)amine, etc.

Although these alkanolamines are highly active as primary, secondary, and tertiary alkanolamines, the action and effect of secondary and tertiary alkanolamines are remarkable. In particular, the action and effect of tertiary alkanolamines are most remarkable.

The ratio of these alkanolamines and the cobalt compound used is usually in the range of 0.5 mol to 20 mol per 1 mol of the cobalt compound. If the amount of alkanolamine used is less than 0.5 mol, The effect of the present invention is not sufficiently exhibited, and if the amount exceeds 20 moles, the effect is not exhibited considering the amount.

Examples of the bases used in the basic reaction medium in the method of the present invention include hydroxides, alkoxides, and phenoxides of metals in Group IA of the periodic table, quaternary ammonium hydroxides, and pyridinium hydroxides. Examples of hydroxides of Group IA metals of the periodic table include bases such as lithium hydroxide, sodium hydroxide, potassium hydroxide, etc.; examples of alkoxides of the metals include lithium methoxide, sodium methoxide, etc. Do,
Potassium methoxide, lithium ethoxide, sodium ethoxide, potassium ethoxide, etc., and phenoxides of the metal include, for example, sodium phenoxide. Furthermore, examples of quaternary ammonium hydroxides and pyridinium hydroxides include tetramethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide, and N-methylhyricinium hydroxide. These bases may be used alone or in combination of two or more. Among these bases, commercially available alkali metal hydroxides such as sodium hydroxide and potassium hydroxide are preferred.

The base linkage is preferably used in an anhydrous state,
If desired, it can be used in the form of an aqueous solution, such as a 40q6 aqueous sodium hydroxide solution, and the amount used can be arbitrarily selected within the range conventionally used.

The catalyst used in the present invention can be easily prepared, for example, by dissolving a cobalt compound in an alcohol such as methanol, adding alkanolamine in a predetermined ratio, and stirring. The bases may be added to this catalyst solution, or may be added to an organic medium in which phenols are dissolved. The catalyst may be prepared in the presence of oxygen, such as at atmospheric pressure, or in a nitrogen atmosphere if desired.The reaction medium used in the method of the present invention includes phenols and catalysts. There is no particular restriction as long as it dissolves the cobalt compound and the alkanolamine, is inert to these compounds, and is liquid at the reaction temperature.Such solvents include, for example, linear and Examples include cyclic aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, nitro compounds, ethers, ketones, lactones, amides, and sulfone compounds. Specific examples include hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, styrene, dichloromethane, chloroform, bromoform, monochlorobenzene, dichlorobenzene, methanol, ethanol, furopanol, butanol, amyl alcohol, hexyl alcohol. , benzyl alcohol, cyclohexyl alcohol, ethylene glycol, trimethylene glycol, butanediol, glycerin, β-chloroethanol, nitrobenzene, diethyl ether, tetrahydrofuran, dioxane, acetone, methyl ethyl ketone, methyl isobutyl ketone, propiolactone, dimethyl formamide, etc. It will be done.

Among these, particularly suitable solvents include ζ, which includes mixed solvents of lower alcohols such as methanol, ethanol, furopanol, and butanol, and aromatic hydrocarbons such as benzene, toluene, and xylene. Moreover, you may combine several types of them arbitrarily. Polar baths such as alcohols in mixed solvents can be used in any proportion. For example, if the molecular weight of polyphenylene ether to be produced is to be increased, the proportion of the polar solvent should be lowered, while if the molecular weight of the polyphenylene ether is to be lowered, the proportion of the polar solvent should be increased.

The ratio of phenol to solvent can be selected within a wide range, but oxidative polymerization is usually carried out when the phenol concentration in the reaction solution is 70% by weight or less, preferably 5 to 40% by weight.

In the method of the invention, oxygen or oxygen diluted with an inert gas, for example air, is used as the oxidizing agent. Although the reaction rate decreases when air is used, it can be used satisfactorily. Regarding the reaction temperature, if it is too low, the reaction will proceed.
If the temperature is too high, the catalyst will be easily deactivated, so it is usually 0~
The temperature is selected from 80°C, preferably from 10 to 60°C. Normal pressure is used as the reaction pressure, but if desired, the reaction can be carried out under increased pressure or reduced pressure. There are no particular restrictions on the post-treatment of the reaction solution, but usually hydrochloric acid or acetic acid is used. Polyphenylene ether can be recovered by a simple operation of adding acid such as to the reaction completion solution to deactivate the catalyst, separating the generated polymer, washing with a solvent that does not dissolve the polymer such as alcohol, and drying. be done.

<Effects of the Invention> Since the method of the present invention uses a highly active catalyst consisting of a cobalt compound and an alkanolamine, the amount of expensive cobalt used can be significantly reduced compared to conventional methods. Furthermore, since it is possible to use alkanolamines such as triethanolamine and jetanolamine, which are commercially available at low cost, the catalyst cost is significantly reduced compared to conventional methods.

Furthermore, since the amount of cobalt compound used is smaller than in conventional methods, the amount of solvent used to remove the catalyst residue in the polymer is also reduced, reducing the cost of recovering the solvent. The equipment for this process can be significantly downsized, and the catalyst removal process can also be simplified.

As described above, by using the method of the present invention, not only can polyphenylene ether be economically advantageously produced, but also the tactile residual content can be almost completely removed, resulting in the great advantage that polyphenylene ether of excellent quality can be obtained. have

<Examples> Next, the present invention will be explained in more detail with reference to Examples, but the present invention is not limited to these Examples in any way.

In addition, the measurement of ηBp/c is performed using the polymer Q, 5 w
/v% chloroform clear solution and conducted at 30°C using an Ubbelohde viscometer.

Example 1 75 f (0,615 mol) of 2.6-dimethylphenol was dissolved in 340 t of toluene, a solution of 20 tvcm of 4.92 f of sodium hydroxide A was added thereto, and further chloride was added. (II) hexahydrate 0.293 f and triethanolamine 1.83 f
A solution prepared by dissolving 65 fVC of methanol was added. Then, while stirring the solution vigorously, oxygen gas was added for 30 minutes.
The mixture was introduced at a flow rate of 0 tnt for 1 minute and reacted at 40° C. for 3.5 hours. After the reaction was completed, the polymerization solution was added to 5 times the volume of a 5% by weight hydrochloric acid methanol solution to precipitate the polymer.

The precipitated polymer had a ηsp/c of 0.84.

In addition, the molar ratio of 2,6-xylenol:Co is soo
: It is 1.

Examples 2 to 7 In Example IVc, cobalt bromide, cobalt sulfate, cobalt acetate, cobalt benzoate, cobal) (I[) acetylacetonate, cobal) (
In) A polymer is obtained in exactly the same manner as in Example 1, except that the same number of moles of acetylacetonate is used in each case. The ηap/c of the polymer is shown in Table 1.

Table 1 Example 8 14 Example 1 is repeated using the same number of moles of treaty propazole amine in place of triethanolamine in Example 1. The ηap/c of this polymer is 0.69.

Example 9 Example 1 was repeated using the same number of moles of nidris(2-yenyl, 2-hydroxyxf)amine in place of triethanolamine in Example 1. This polymer paste 8P/c is 0.54.

Example 1O Example 1 is repeated using the same mole number of potassium hydroxide in place of IJium. The ηsp/c of this polymer is 0.81.

Example 11 Example 1 (i
-Repeat. The ηsp/c of this polymer would be 0.72 to Example 12.16 In Example 1, the triethanolamine solution was
A polymer is obtained in exactly the same manner as in Example 1, except that the molar ratio of :amine is from 1:0.5 to 1:20. The ηBp/c of the polymer is shown in Table 2.

Table 2 Examples 17 to +9 In Example 11c, the amount of cobalt chloride used was 2.6-
A polymer is obtained in exactly the same manner as in Example 1, except that the molar ratio of dimethylphenol:Co is 250:1 to 2000:1.

The ηsp/c of this polymer is shown in Table 3.

Table 3 with blank spaces below Example 20 75 t (0,615 mol) of 2.6-dimethylphenol was dissolved in a mixed solvent of xylene 2552 and n-butanol 852 using VCFi, and 1.4 t of sodium hydroxide was added to the solution.
Add a solution of 8f in methanol 2otvr and 14g,
Furthermore, a solution of 0.586 f of cobalt chloride and 1.29 g of jetanolamine in 652 g of methanol was added. Thereafter, a polymer was obtained in the same manner as in Example 1. The ηsp/c of this polymer was 0.67.

In addition, the molar ratio of 2.6-xylenol:Co is 250
: It is 1.

Example 21 75 f (0,615 mol) of 2.6-dimethylphenol was dissolved in a mixed solvent of 255 t of xylene and 852 t of n-butanol, and 1.48 t of sodium hydroxide was added thereto.
A solution of 20 rKm of methanol was added, and then 1.465F of cobalt chloride and 1.500F of ethanolamine were added.
A solution of f in methanol 659 was added. Thereafter, a polymer was obtained in the same manner as in Example 1. The da sp/c of this polymer was 0.43.

Note that the molar ratio of 2,6-xylenol to 2000 is 100
: l is 0 Example 22 75 f (0,615 mol) of 2.6-dimethylphenol was dissolved in a mixed solvent of 255 t of xylene and 85 f of n-butanol, and 1.482 mol of sodium hydroxide was dissolved therein.
A solution of 20PK of methanol was added, and then 0.293t of cobalt chloride and 1.83t of triethanolamine were added.
A solution of f and f in methanol 651F was added.

Polymer ft was obtained in the same manner as in Example 1. The ηsp/c of this polymer is 0.74.

Comparative Example 1 75 f of 2,6-dimethylphenol (0,615 mol) was dissolved in 340 f of toluene, to which was added a solution of 4.92 f of sodium chloride dissolved in 209 methanol, and further 0.293 f of cobalt chloride. A solution of was dissolved in methanol 659 was added.

Polymerization was carried out in the same manner as in Example 1, but no polymer was obtained.

Comparative Example 2 In Example I, when the polymerization was carried out without using sodium hydroxide, no polymer was polymerized at all.

Claims (1)

[Claims] A method for polymerizing polyphenylene ethers, which comprises contacting phenols with an oxygen-containing gas in a basic reaction medium in the presence of a catalyst consisting of a cobalt compound and an alkanolamine.