JPH0674322B2 - Polymerization method of substituted phenols - Google Patents

Description

TECHNICAL FIELD The present invention relates to a method for polymerizing substituted phenols. More specifically, the present invention uses, as a raw material, phenols in which the para-position is not substituted with respect to a hydroxyl group as a raw material, and uses a highly active catalyst system to produce a polyphenylene ether of excellent quality in a good yield and economically. It relates to a method of manufacturing advantageously.

Conventional Technology Conventionally, para-unsubstituted oxidative polymers of phenols are known as polyphenylene ethers, which are excellent in 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 plastic.

By the way, it is well known to use a manganese compound as a catalyst when producing polyphenylene ether by oxidative polymerization of phenols, and various methods for producing polyphenylene ether using this manganese compound have been proposed so far. Has been done. For example, a method of polymerizing a phenol in the presence of a manganese compound and a hydroxide of an alkali metal, an alkoxide, a basic compound such as a phenoxide (Japanese Patent Publication No. 45-30354), a manganese compound,
A method of polymerizing phenols in the presence of primary amine and alcohol (Japanese Patent Publication No. Sho 47-36518) has been proposed.

However, in these methods, since the amount of the manganese compound used is large, the process of removing the catalyst residue from the produced polymer is complicated, and in addition to requiring a large amount of cost to remove the catalyst, The catalyst in the polymer cannot be completely removed, and the quality of the polymer is inevitably deteriorated by the residual catalyst residue.

In addition, as a method of using a manganese chelate as a catalyst, N,
A catalyst system comprising N'-ethylenebis (salicylideneiminato) manganese and primary to tertiary amines has been disclosed (Japanese Patent Publication No. 26395/48). However, since this catalyst system also uses a large amount of the manganese compound, it is unavoidable that the cost is high due to the removal of the catalyst and the quality is deteriorated by the residual catalyst.

Therefore, a method using another type of Mn chelate catalyst has been attempted as a catalyst that requires a small amount of a manganese compound (JP-A-57-147517, JP-A-58-12).
2919, Japanese Patent Publication No. 59-21895). However, this Mn chelate catalyst is very effective to some extent,
It has the drawback that its action is still insufficient and that the preparation of the catalyst is expensive.

On the other hand, it is known that in the polymerization reaction of phenols, water is produced as the polymerization proceeds, and this produced water usually has a bad influence on the catalyst, resulting in a decrease in the degree of polymerization and a yield. Then, as the amount of catalyst used decreases, the relative amount of produced water with respect to the catalyst increases, so that the influence of water becomes even greater. Therefore, if the activity of the catalyst is increased, the amount of the catalyst used can be reduced and the influence of water can be reduced. Therefore, the development of such a catalyst has been desired. The Mn chelate catalyst has not been sufficient in this respect either.

Problems to be Solved by the Invention Under the circumstances, an object of the present invention is to use a catalyst having high activity and excellent water resistance, and to a hydroxyl group under a condition where the amount of the catalyst used is small. An object of the present invention is to provide a method for polymerizing substituted phenols, which is capable of economically and advantageously producing a polyphenylene ether having excellent quality by oxidatively polymerizing para-unsubstituted phenols.

Means for Solving the Problems As a result of intensive studies to achieve the above-mentioned object, the present inventors have found that a catalyst composed of a manganese compound, a certain benzylidene compound and a secondary alkanolamine is used in a basic reaction medium. It was found that the object can be achieved by oxidative polymerization of phenols used in the above-mentioned method, and based on this finding, the present invention has been completed.

That is, the present invention, in a basic reaction medium, with a manganese compound, the general formula (A in the formula is a divalent hydrocarbon residue, R ₁ and R ₂ are hydrogen atoms or hydrocarbon groups, X ₁ and X ₂ are hydrogen atoms, halogen atoms,
A hydrocarbon group, an alkoxy group, a phenoxy group, a hydroxyl group, an amino group, a substituted amino group or a nitro group) in the presence of a catalyst composed of a secondary alkanolamine and a para position relative to the hydroxyl group. Provides a method for polymerizing substituted phenols, which comprises contacting an unsubstituted phenol with an oxygen-containing gas.

By the way, by adding a secondary alkanolamine to the manganese chelate catalyst of ω-hydroxyoxime,
A method for delaying the polymerization rate has been disclosed (JP-A-53).
-79995 publication). Therefore, in the present invention, increasing the catalytic activity by adding a secondary alkanolamine to the compound represented by the general formula (I) and the manganese compound is a completely unexpected and unique effect. I understand.

The phenols used in the method of the present invention have the general formula Is a phenol derivative in which the para-position is unsubstituted with respect to the hydroxyl group. R, R ′, R ″ and R in the general formula (II)
Is a hydrogen atom, a halogen atom, a hydrocarbon group, a halohydrocarbon group or a hydrocarbon oxy group, which may be the same or different, and the hydrocarbon group or the hydrocarbon moiety is a tertiary-α. It is preferably free of hydrocarbons. Examples of such phenols include 2,6
-Dimethylphenol, 2-methyl-6-ethylphenol, 2,6-diethylphenol, 2-methyl-6-n
-Propylphenol, 2-methyl-6-iso-propylphenol, 2-methyl-6-methoxyphenol,
2,6-dimethoxyphenol, 2,6-diphenylphenol, 2,3,6-trimethylphenol, 2,3,5,6-tetramethylphenol, 2,6-dimethyl-3-chlorophenol, 2,6 -Diphenylphenol, o-cresol, m
-Cresol and the like. These may be used alone or in combination of two or more.

As the manganese compound used in the method of the present invention, any one of divalent, trivalent, tetravalent and heptavalent salts or compounds can be used. Examples of the divalent manganese salt include manganese chloride (II), manganese bromide (II),
Manganese iodide (II), manganese (II) sulfate, manganese (II) nitrate, manganese (II) phosphate, manganese carbonate (I
I), manganese (II) acetate, manganese oxalate (II),
Manganese (II) benzoate, manganese (II) acetylacetonate, manganese (II) stearate, manganese (II) formate, and the like and hydrates thereof can be used as trivalent manganese salts such as manganese (II) acetyl. Acetonate,
Examples of the tetravalent or heptvalent manganese compound such as manganese (III) sulfate and hydrates thereof include sodium manganate, potassium manganate, sodium permanganate, and potassium permanganate. Among these manganese compounds, divalent and trivalent manganese salts which are soluble in the reaction medium are preferred.

The amount of the manganese compound used is usually 0.01 mol% or more, preferably 0.02 to 2 mol%, relative to the phenols. If the amount used is less than 0.01 mol%, the effect as a catalyst is not sufficiently exhibited, and if it exceeds 2 mol%, the molecular weight control becomes difficult due to an increase in the rate of formation of phenylene ether, and moreover the catalyst in the polymer. Becomes difficult to remove.

In the method of the present invention, as the chelating agent for the manganese compound, a compound represented by the general formula (Wherein A, R ₁ , R ₂ , X ₁ and X ₂ have the same meanings as described above), A is a divalent straight chain, branched chain or saturated monocyclic ring. , An aromatic monocyclic hydrocarbon residue. Further, X ₁ and X ₂ are each a hydrogen atom, a halogen atom, an alkyl group, a cycloalkyl group, a hydrocarbon group such as an aryl group, or an alkoxy group, a phenoxy group, a hydroxyl group,
An amino group, a monoalkylamino group, a dialkylamino group and a nitro group, which may be the same or different from each other. Further, R ₁ and R ₂ are each a hydrogen atom, an alkyl group, a cycloalkyl group or an aryl group, and they may be the same or different from each other.

In the compound represented by the general formula (I), it is preferred that A has a main chain prime number of 2 to 6, particularly 2 to 3, and specific examples thereof include an ethylene group, a propylene group,
A trimethylene group, a 1,2-cyclohexylene group, an o-phenylene group, an m-phenylene group and the like can be mentioned. Also,
X ₁ and X ₂ are preferably a hydrogen atom or a lower alkyl group, and R ₁ and R ₂ are preferably a hydrogen atom or a lower alkyl group such as a methyl group or an ethyl group.

In the general formula (I), specific examples of the compound in which R ₁ and R ₂ are hydrogen atoms and X is a hydrogen atom include:
N, N'-bis (salicylidene) ethylenediamine, N, N '
-Bis (salicylidene) trimethylenediamine, N, N '
-Bis (salicylidene) propylenediamine, N, N'-
Bis (salicylidene) -o-phenylenediamine, N,
N'-bis (salicylidene) -m-phenylenediamine, N, N'-bis (salicylidene) -1,2-cyclohexylenediamine and the like can be mentioned. Specific examples of compounds in which R ₁ and R ₂ are hydrogen atoms and X is a substituent other than a hydrogen atom include N, N′-bis (5-methylsalicylidene) ethylenediamine, N, N ′ -Bis (5-chlorosalicylidene) ethylenediamine, N, N′-bis (5-
Nitrosalicylidene) ethylenediamine, N, N'-bis (5-methoxysalicylidene) ethylenediamine, N,
Examples thereof include N'-bis (5-diethylaminosalicylidene) ethylenediamine and N, N'-bis (3-methoxysalicylidene) ethylenediamine.

Further, specific examples of the compound in which R ₁ and R ₂ are substituents other than hydrogen atom include 1,2-bis (o-hydroxyacetophenoneimino) ethane and 1,3-bis (o-hydroxyacetophene). Examples thereof include nonimino) propane, 1,2-bis (o-hydroxybenzophenoneimino) ethane, and 1,3-bis (o-hydroxybenzophenoneimino) propane.

The ratio of these compounds to the manganese compound used is usually 0.2 mol or more, preferably 0.5 to 4 mol, per 1 mol of the manganese compound. If the amount of the compound represented by the general formula (I) used is less than 0.2 mol, the effect of the present invention is not sufficiently exhibited, and if it exceeds 4 mol, the effect cannot be expected for the amount.

Examples of the secondary alkanolamine used in the method of the present invention include diethanolamine, di-i-propanolamine, bis (2-hydroxy-2-phenylethyl) amine and N- (2-hydroxypropyl) ethanolamine. However, among these, diethanolamine is particularly preferable.

These secondary alkanolamines may be used alone or in combination of two or more, and the amount thereof is usually 0.1 mol or more relative to the phenols,
It is preferably selected in the range of 0.5 to 10 mol%. That amount
If it is less than 0.1 mol%, the catalyst activation effect is small, and
If it exceeds mol%, the effect of activating the catalyst cannot be expected for the amount.

Examples of the bases used in the basic anti-medium in the method of the present invention include hydroxides of Group IA metals, alkoxides, phenoxides, and bases such as quaternary ammonium hydroxides and pyridinium hydroxides. Is mentioned. Examples of the hydroxide of Group IA metal of the periodic table include lithium hydroxide, sodium hydroxide, potassium hydroxide and the like, and examples of the alkoxides of the metal include lithium methoxide, sodium methoxide, potassium methoxide and lithium. Ethoxide, sodium ethoxide, potassium ethoxide and the like, and examples of the metal phenoxides include sodium phenoxide and the like. Furthermore, examples of the quaternary ammonium hydroxides and pyridinium hydroxides include tetramethylammonium hydroxide, tetrabutylammonium hydroxide, trimethylbenzylammonium hydroxide and N-methylpyridinium 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, which are usually easily available, are preferable.

The bases are preferably used in an anhydrous state,
If desired, it can be used in the form of an aqueous solution such as 40% sodium hydroxide aqueous solution, and the amount used is usually 0.5 to 50 mol% relative to the phenols,
It is preferably selected in the range of 1 to 20 mol%.

The catalyst used in the present invention is prepared by dissolving a manganese compound in an alcohol such as methanol and then adding the compound of the general formula (I)
It is easily prepared by adding the compound represented by the formula (1) at a predetermined ratio and stirring. The bases may be added to this catalyst solution, or the secondary alkanolamine may be added together with the bases to the organic medium in which the phenols are dissolved. The catalyst may be prepared in the presence of oxygen, such as under atmospheric pressure, or in a nitrogen atmosphere if desired.

The reaction medium used in the method of the present invention dissolves the phenols and the catalyst manganese compound and the compound represented by the general formula (I), is inactive to these compounds, and is liquid at the reaction temperature. As long as
There is no particular limitation, and examples of such a solvent include linear and cyclic aliphatic hydrocarbons, aromatic hydrocarbons, halogenated hydrocarbons, alcohols, nitro compounds, ethers, ketones, lactones, amides. , Sulfone compounds and the like. Specific examples include hexane, heptane, octane, cyclohexane, methylcyclohexane, benzene, toluene, xylene, styrene, dichloromethane, chloroform, bromoform, monochlorobenzene, dichlorobenzene, methanol, ethanol,
Propanol, 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,
Examples include methyl isobutyl ketone, propiolactone, dimethylformamide, and the like. Among these, a particularly preferable solvent is a mixed solvent of a lower alcohol such as methanol, ethanol, propanol and butanol and an aromatic hydrocarbon such as benzene, toluene and xylene. Moreover, you may combine those several types arbitrarily. The polar solvent such as alcohol in the mixed solvent can be used in any ratio. For example, when the molecular weight of the polyphenylene ether to be produced is to be increased, the ratio of the polar solvent is lowered, and when the molecular weight of the polyphenylene ether is desired to be lowered, the ratio of the polar solvent is preferably increased.

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

In the method of the present invention, oxygen or oxygen diluted with an inert gas such as air is used as the oxidant. Although the reaction rate decreases when air is used, it can be sufficiently used. Regarding the reaction temperature, if the reaction temperature is too low, the reaction is difficult to proceed, and if it is too high, the catalyst is easily deactivated.
It is selected in the range of 70 ° C, preferably 10 to 50 ° C. Although normal pressure is used as the reaction pressure, the reaction can be carried out under pressure or under reduced pressure if desired.

In the method of the present invention, small amounts of primary, secondary and tertiary amines may coexist if desired. By using these amines, effects such as lightening of the color of the polymer and improvement of thermal stability can be obtained. When using amines,
It is preferably used in the range of 0.1 to 5 mol% with respect to the phenols.

Useful amines include primary and secondary alkyl amines having 1 to 10 carbon atoms such as n-heptylamine, n-butylamine, di-n-butylamine and the like.

The post-treatment of the reaction-terminated liquid is not particularly limited, but usually, an acid such as hydrochloric acid or acetic acid is added to the reaction-terminated liquid to deactivate the catalyst, and then the produced polymer is separated to remove alcohol such as alcohol. The polyphenylene ether is recovered by a simple operation of washing with a solvent that does not dissolve the polymer and then drying.

EFFECTS OF THE INVENTION In the method of the present invention, since a highly active catalyst comprising a manganese compound, a compound represented by the general formula (I) and a secondary alkanolamine is used as a catalyst, a manganese compound is used as compared with a conventional method. As a result, the amount of solvent used for removing the catalyst residue in the polymer may be small, and the equipment for removing the catalyst may be remarkably downsized. Was converted into
Moreover, since the catalyst residue can be removed almost completely, a polyphenylene ether of excellent quality can be obtained.

Further, in the oxidative polymerization reaction of phenols, water is generated as the polymerization progresses, and this generated water usually has an adverse effect on the catalyst, but when the amount of the catalyst is small, the relative ratio of the generated water to the catalyst is small. , The effect will be even greater. Particularly in continuous polymerization, unlike batch polymerization, the water produced is always present in the system, so the relative proportion of water increases when the amount of catalyst used is small. Therefore, in the conventional catalyst, it is usually necessary to substantially increase the amount of the catalyst used, whereas in the catalyst of the method of the present invention, the influence of water is small and the water resistance is excellent. Even in a system in which is present, there is a great advantage that it is hardly affected by water and high activity can be maintained even in continuous polymerization.

EXAMPLES Next, the present invention will be described in more detail with reference to examples, but the present invention is not limited to these examples.

The measurement of ηsp / c was carried out at 30 ° C. using a Ubbelohde viscometer with a 0.5 W / V% chloroform solution of the polymer.

Example 1 75 g (0.615 mol) of 2,6-dimethylphenol was mixed with 2 parts of xylene.
It was dissolved in a mixed solvent of 55 g and 85 g of n-butanol, to which a solution of 1.48 g of sodium hydroxide in 20 g of methanol was added, and then 1.29 g of diethanolamine was added, and manganese (II) chloride tetrahydrate was added. A solution of 0.244 g and 0.330 g of N, N'-bis (salicylidene) ethylenediamine in 65 g of methanol was added. Next, while vigorously stirring this solution, oxygen gas was introduced at a flow rate of 300 Nml / min, and the reaction was carried out at 30 ° C. for 3.5 hours. After completion of the reaction, the polymer solution was added to 5 times by weight of a 5 wt% methanol solution of hydrochloric acid to precipitate a polymer.

The ηsp / c of the precipitated polymer was 0.88.

The molar ratio of 2,6-xylenol: Mn is 500: 1.

Example 2 75 g (0.615 mol) of 2,6-dimethylphenol was mixed with 2 parts of xylene.
It was dissolved in a mixed solvent of 55 g and 85 g of n-butanol, to which a solution of 1.48 g of sodium hydroxide in 20 g of methanol was added, and then 1.29 g of diethanolamine was added, and manganese (II) chloride tetrahydrate was added. A solution prepared by dissolving 0.244 g and 0.330 g of N, N'-bis (salicylidene) ethylenediamine in 65 g of methanol was added. Next, 11.1 g of water corresponding to the water produced by polymerization was added to this solution and stirred, and then oxygen gas was introduced at a flow rate of 300 Nml / min with vigorous stirring, and the reaction was carried out at 30 ° C. for 3.5 hours. Then, the same treatment as in Example 1 was carried out to obtain a precipitated polymer. Ηsp / c of the precipitated polymer was 0.86, which was almost the same as in Example 1 when water was not added.

The results show that the catalyst of the present invention has excellent water resistance.

Comparative Example 1 A polymer was obtained in exactly the same manner as in Example 2 except that monoethanolamine was used in the same molar amount in place of diethanolamine. Ηsp / c of this polymer is
It is 0.22, which is remarkably low as compared with the case of using diethanolamine.

Comparative Example 2 A polymer was obtained in exactly the same manner as in Example 2 except that triethanolamine was used in the same molar amount in place of diethanolamine. Ηsp / c of this polymer is
0.25, which is remarkably low as compared with the case of using diethanolamine.

From the results of Comparative Examples 1 and 2, it can be seen that the catalytic activity is specifically increased by using diethanolamine which is a secondary alkanolamine.

Comparative Example 3 A polymer was obtained in the same manner as in Example 2 except that ethylenediamine was used in the same molar amount in place of diethanolamine. Ηsp / c of this polymer is 0.27
And is significantly lower than when diethanolamine is used.

Examples 3 to 8 Polymers were obtained in the same manner as in Example 2 except that the same molar amount of the compound shown in Table 1 was used instead of N, N'-bis (salicylidene) ethylenediamine. . The ηsp / c of the polymer is shown in Table 1.

Examples 9 to 12 Polymers were prepared in the same manner as in Example 2 except that the same molar amounts of divalent and trivalent manganese compounds were used in place of manganese (II) chloride tetrahydrate. Obtained.
The results are shown in Table 2.

Example 13 A polymer was obtained in the same manner as in Example 2 except that potassium hydroxide was used as the base in place of sodium hydroxide in the same molar amount. Ηsp / c of polymer is 0.
It was 86.

Example 14 A polymer was obtained in exactly the same manner as in Example 2 except that the organic base, tetramethylammonium hydroxide, was used in the same molar amount in place of sodium hydroxide as the base. Ηsp / c of this polymer is 0.87,
There was almost no difference from the case of sodium hydroxide.

Example 15 It carries out by changing a solvent composition.

That is, 75 g of 2,6-dimethylphenol (0.615 mol)
Was dissolved in 340 g of toluene, and sodium hydroxide 1.48 was added to it.
A solution prepared by dissolving g in 20 g of methanol was added, and then a solution of 0.244 g of manganese (II) chloride tetrahydrate and 0.330 g of N, N'-bis (salicylidene) ethylenediamine in 65 g of methanol was added. Thereafter, the same procedure as in Example 2 was carried out to obtain a polymer. The ηsp / c of this polymer was 0.80.

Examples 16 to 18 The same procedure as in Example 2 except that the amount of manganese chloride used was changed to a molar ratio of 2,6-dimethylphenol: Mn of 250: 1 to 2000: 1. To obtain a polymer. The ηsp / c of the polymer is shown in Table 3.

Examples 19 to 22 Examples 22 to 22 except that the ratio of Mn to N, N'-bis (salicylidene) ethylenediamine as a chelating agent was changed to a molar ratio of 1: 0.5 to 1: 5. Two
A polymer was obtained in exactly the same manner as in. Table 4 shows the ηsp / c of the polymer.

Example 23 A polymer was obtained in exactly the same manner as in Example 2 except that the reaction temperature was changed from 30 ° C to 20 ° C. The ηsp / c of this polymer was 0.68.

Example 24 A polymer was obtained in exactly the same manner as in Example 2 except that the reaction temperature was changed from 30 ° C to 40 ° C. The ηsp / c of this polymer was 0.90.

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Claims (1)

[Claims] 1. A manganese compound and a general formula in a basic reaction medium. (A in the formula is a divalent hydrocarbon residue, R ₁ and R ₂ are hydrogen atoms or hydrocarbon groups, X ₁ and X ₂ are hydrogen atoms, halogen atoms,
A hydrocarbon group, an alkoxy group, a phenoxy group, a hydroxyl group, an amino group, a substituted amino group or a nitro group) in the presence of a catalyst composed of a secondary alkanolamine and a para position relative to the hydroxyl group. A method for polymerizing substituted phenols, which comprises contacting an unsubstituted phenol with an oxygen-containing gas.