JPH11158265A - Catalyst for oxidative polymerization of phenolic compound and production of polymer in the presence of the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain a catalyst which is not inactivated during use in polymerization and can give a polymer within a short time in high yields even when used in a small amount under extensive polymerization conditions by including a copper compound and an amino-containing thioether compound. SOLUTION: The copper compound used is exemplified by cupric chloride and is used in an amount of 0.01-1 mol per 100 mol of the phenolic compound. The thioether compound is represented by the formula (wherein R1 and R2 are each a hydrocarbon group; and R3 and R4 are each H or a hydrocarbon group) and is, for example, 2-methylthioethylamine or 3-methylthiopropylamine. Although not particularly limited, its amount of use is desirably in the range of 1-100 mol per mol of the copper. By adding an amine compound (e.g. dimethylamine) to this catalyst system, its catalytic activity can further improved to reduce the amount of the catalyst necessary for obtaining a polyphenylene ether.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a method for producing high-quality polyphenylene ether using a highly active catalyst having improved water resistance. More specifically, a high-quality polyphenylene ether is obtained by oxidatively polymerizing a phenolic compound with oxygen in the presence of a catalyst having high polymerization activity and improved water resistance comprising a copper compound, a thioether compound having an amino group, and an amine. And a method for producing the same.

[0002]

2. Description of the Related Art Hitherto, an oxidized polymer of a phenolic compound is known as a polyphenylene ether, which is excellent in mechanical properties, electrical properties, heat resistance, etc., and has low water absorption and dimensional stability. In recent years, it has been noted as a thermoplastic engineering plastic because it has good properties.

In the production of polyphenylene ether by oxidative polymerization of a phenolic compound, a polymerization catalyst includes:
Copper compound and diamine (JP-B-63-135423) or copper compound and mercapto compound (JP-B-56-5)
2046), various copper complexes have been reported. Among them, when a catalyst system composed of a copper compound and a diamine is used as a polymerization catalyst, the catalyst is deactivated during the polymerization. There are many restrictions on polymerization conditions, such as limiting the type of solvent and adding a dehydrating agent.

When a catalyst system composed of a copper compound and a mercapto compound is used as a polymerization catalyst, the catalyst activity is low, and a large amount of catalyst must be added to obtain a high-yield polymer. There is a problem.

[0005]

SUMMARY OF THE INVENTION An object of the present invention is to provide a catalyst capable of preventing deactivation of a catalyst in the course of polymerization and obtaining a polymer in a short time and with a small amount of a catalyst under a wide range of polymerization conditions. An object of the present invention is to provide a method for producing polyphenylene ether.

[0006]

Means for Solving the Problems The present inventors have conducted intensive studies on a method for producing polyphenylene ether, and have found that a copper compound, a thioether compound having an amino group,
When a catalyst system composed of an amine compound is used as a polymerization catalyst for polyphenylene ether, a polymer can be obtained in a short time and with high yield because of high polymerization activity and a small amount of catalyst deactivated during polymerization. The inventors have found that the present invention has been achieved.

That is, the present invention is as follows. (1) Copper compound and the following formula (1)

[0008]

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A catalyst for oxidative polymerization of phenolic compounds, which comprises a thioether compound having an amino group represented by the formula: (2) The catalyst for oxidative polymerization of a phenolic compound according to the above (1), wherein the thioether compound having an amino group is 2-methylthioethylamine. (3) The catalyst for oxidative polymerization of a phenolic compound according to the above (1), wherein the thioether compound having an amino group is 3-methylthiopropylamine. (4) The catalyst for oxidative polymerization of a phenolic compound according to (1), further comprising an amine compound in addition to the thioether compound. (5) A method for producing polyphenylene ether, comprising oxidatively polymerizing a phenolic compound with oxygen in the presence of the catalyst according to any one of (1) to (4).

In the method for producing polyphenylene ether of the present invention, copper compounds usable as a catalyst include cupric halides such as cupric chloride, cupric bromide, cupric iodide, and sulfate sulfate. Copper, cupric nitrate, cupric acetate, cupric azide, etc., and cuprous chloride, cuprous bromide, cuprous iodide, cuprous sulfate, cuprous nitrate, cuprous acetate Copper is exemplified.

Preferred copper compounds include cupric chloride,
Cupric bromide, cuprous chloride and cuprous bromide. These copper salts may be synthesized at the time of use from oxides, carbonates, hydroxides and the like and halogen or hydrogen halide. The amount of the copper compound used is preferably in the range of 0.01 mol to 1 mol, more preferably in the range of 0.05 mol to 0.5 mol, per 100 mol of the phenolic compound.

Specific examples of the thioether compound having an amino group in the present invention include 2-methylthioethylamine, 3-methylthiopropylamine, 3-methylthio-N-methylpropylamine, and 3-methyl-N, N-dimethylpropylamine. Etc. Of these, 2-methylthioethylamine and 3-methylthiopropylamine are preferred. The amount of the thioether compound having an amino group is not particularly limited, but is preferably in the range of 1 mol to 100 mol, more preferably 2 mol to 10 mol, per 1 mol of copper.

The catalytic activity of the thioether compound having a copper compound and an amino group in the present invention is further improved by adding an amine compound to the catalyst system.
The amount of catalyst required to obtain polyphenylene ether can also be reduced. In oxidative polymerization of a phenolic compound, the polymerization reaction proceeds by coordination of a phenolate anion species generated from the phenolic compound to a catalyst system. The addition of the amine compound promotes the formation of the phenolate anion, and the polymerization reaction proceeds more rapidly.

The amine compound used in the present invention is an aliphatic or aromatic primary, secondary or tertiary monoamine. Aliphatic or aromatic primary, secondary, and tertiary amines have a structure in which an aliphatic hydrocarbon or an aromatic hydrocarbon is substituted as a nitrogen substituent of a corresponding compound. In the nitrogen substituent of the tertiary amine, a substituent of only an aliphatic hydrocarbon may be used, or a substituent of only an aromatic hydrocarbon may be used.
A coexisting substituent of an aromatic hydrocarbon may be used. Cyclic compounds containing a nitrogen atom as a hetero atom include any compounds having a nitrogen atom in the cyclic skeleton.

Specific examples of the amine compound include dimethylamine, diethylamine, diisopropylamine, dibutylamine, trimethylamine, triethylamine and trihexylamine. The use amount of these amine compounds is not particularly limited, but is preferably in the range of 2 mol to 200 mol per 1 mol of copper. More preferably, it is in the range of 5 mol to 100 mol.

The catalyst can be prepared using a solvent such as methanol. If care is taken to dissolve the copper compound, the object can be achieved by methods commonly known to those skilled in the art. It may be prepared in the atmosphere. The phenolic compound used in the present invention has the following formula (2)

[0017]

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Examples of such a compound include, for example, 2,6-dimethylphenol, 2,3,6-trimethylphenol, 2-methyl-6-ethylphenol, 6-diethylphenol, 2-ethyl-6-n-propylphenol, 2-methyl-6-chlorophenol, 2-methyl-6-bromophenol, 2-methyl-6-isopropylphenol, 2-methyl-6-n -Propylphenol, 2-ethyl-6-bromophenol, 2-methyl-6-n-butylphenol, 2,6-di-n-propylphenol, 2-ethyl-6-chlorophenol, 2-methyl-
Examples thereof include 6-phenylphenol, 2,6-diphenylphenol, 2,6-bis- (4-fluorophenyl) phenol, 2-methyl-6-tolylphenol, and 2,6-ditolylphenol.

These phenolic compounds may be used alone or in combination of two or more.
A small amount of phenol, o-cresol, m-cresol, p-cresol, 2,4-dimethylphenol,
-Even if ethylphenol or the like is contained, it does not matter substantially. Of these phenolic compounds, 2,6-dimethylphenol is particularly important. When the phenolic compound is oxidatively polymerized in the present invention, the ratio of the phenolic compound to the solvent can be selected in a wide range, but the concentration of the phenolic compound in the mixture is generally 70% by weight or less. More preferably, it is in the range of 5 to 40% by weight, more preferably 8 to 35% by weight.

The reaction solvent used in the production method of the present invention is hardly oxidized as compared with the phenolic compound to be oxidized, and has almost reactivity with various radicals which are considered to be generated in the middle of the reaction process. There is no particular limitation as long as it does not do so, but it is preferable to dissolve the low molecular weight phenolic compound and dissolve part or all of the catalyst mixture.

Examples of such solvents include, for example, aromatic hydrocarbons such as benzene, toluene, xylene and ethylbenzene, chloroform, methylene chloride, 1,2-dichloroethane, trichloroethane, chlorobenzene, dichlorobenzene and trichlorobenzene. And nitro compounds such as nitrobenzene, which can be used as a good solvent for the polymer.

Examples of the poor solvent for the polymer include alcohols such as methanol, ethanol, propanol, butanol, benzyl alcohol, and cyclohexanol; aliphatic hydrocarbons such as pentane, hexane, heptane, cyclohexane, and cycloheptane; And ketones such as methyl ethyl ketone, esters such as ethyl acetate and ethyl formate, ethers such as tetrahydrofuran and diethyl ether, amides such as dimethylformamide, sulfoxides such as dimethyl sulfoxide, and water. One or more of these good solvents and, if necessary, one or more of poor solvents can be mixed and used.

A solution polymerization method can be obtained by selecting a ratio of a good solvent and a poor solvent to polyphenylene ether, which is a polymer obtained by oxidative polymerization of a phenolic compound, and the reaction can be performed by increasing the ratio of a poor solvent. As the process proceeds, a precipitation polymerization method in which the polymer is precipitated as particles in the reaction solvent is also provided. The present invention can be applied to polymerization methods such as a batch polymerization method, a continuous polymerization method, a solution polymerization method, and a precipitation polymerization method.

The addition of a basic compound such as an alkali metal hydroxide, an alkaline earth metal hydroxide, or an alkali metal alkoxide to the polymerization reaction system promotes the formation of phenolate anion from the phenolic compound. However, it is preferable in increasing the polymerization reaction rate. It is preferable to add a neutral salt such as magnesium sulfate and calcium chloride, a surfactant, zeolite, and the like to the polymerization reaction system in order to remove water generated as the polymerization proceeds. .

The polymerization reaction temperature in the present invention is not particularly limited. However, if the temperature is too low, the reaction hardly proceeds, and if it is too high, the catalyst may be deactivated.
It is desirable to carry out at a temperature of 0 ° C, more preferably 10 to 70 ° C. As the oxygen in the oxidative polymerization of the present invention, in addition to pure oxygen, those mixed with an inert gas such as nitrogen at an arbitrary ratio, air, and the like can be used. The pressure in the system during the reaction is usually at normal pressure, but it can be used under reduced pressure or under increased pressure as needed.

Regarding the post-treatment method after the completion of the polymerization reaction,
There is no particular limitation. Usually, an acid such as hydrochloric acid or acetic acid, or ethylenediaminetetraacetic acid and a salt thereof, nitrilopolyacetic acid and a salt thereof, and the like are added to the reaction solution to deactivate the catalyst. The polyphenylene ether can be recovered by a simple operation of washing with a solvent that does not dissolve the coalescence and drying.

[0027]

Next, the present invention will be described in more detail by way of examples. The measuring method is as follows. The polymerization activity was evaluated in two ways: a method for measuring the polymerization rate and a method for measuring the viscosity of the polymer. (1) Measurement of polymerization rate At the beginning of polymerization, the differential coefficient of the amount of oxygen absorbed with respect to the polymerization time was measured using a gas burette, and the number of moles of oxygen absorbed per minute (mmol oxygen / min)
Expressed by (2) Measurement of viscosity of polymer (ηsp / c) A 0.5 g / 100 ml chloroform solution of polyphenylene ether was measured at 30 ° C. using an Ubbelohde viscometer.

[0028]

Example 1 In a 200 ml four-necked flask,
2.75 g (22.5 mmol) of 6-dimethylphenol, 0.30 g (2.96 mmol) of triethylamine, 8.85 g of toluene, 2.95 g of n-butanol,
2.95 g of methanol was added and stirred, and 2,6-dimethylphenol was completely dissolved to prepare a monomer solution. Separately, cupric chloride dihydrate 0.02
1.95 g of methanol in 25 g (0.132 mmol)
Was added to the methanolic cupric chloride solution
-Methylthioethylamine 0.048 g (0.528 mmol), toluene 5.84 g, n-butanol 1.9
A solution consisting of 5 g was added and mixed well to obtain a catalyst solution.
This catalyst solution was placed in a dropping funnel and then attached to a four-necked flask, and a cooling tube and a thermometer were attached to the remaining ports. The upper port of the cooling pipe was connected to a gas burette, a manometer, and a valved oxygen exhaust pipe for measuring oxygen absorption. Oxygen was introduced from the introduction pipe and the inside of the system was replaced with oxygen while excluding air from the system from the discharge pipe. During the polymerization, the temperature of the water bath was always kept at 40 ° C.

The valve of the oxygen inlet tube and the valve of the oxygen outlet tube were closed and the system was allowed to stabilize. The catalyst solution was added at once from the dropping funnel into the flask, and the polymerization was started with vigorous stirring. The composition of the mixed solution immediately after mixing is as follows. That is, 2,6-dimethylphenol in the mixture contains 1
0% by weight, the solvent weight ratio is a ratio of toluene: n-butanol: methanol = 60: 20: 20, and copper is 0.59 with respect to the number of moles of 2,6-dimethylphenol.
Mol%, and 2-methylthioethylamine is 2,6-
2.36 mol% is based on the number of moles of dimethylphenol, and triethylamine is 13.2 mol% based on the number of moles of 2,6-dimethylphenol.

The temperature of the polymerization solution was controlled at 40.degree. The amount of oxygen absorbed with respect to the polymerization time was determined using a gas burette, and the polymerization rate in a steady state was determined. The polymerization rate was 0.94 mmol oxygen / min. The reaction liquid became a slurry during the polymerization. Two hours after the start of the polymerization, the polymerization solution was added to a large amount of methanol to obtain a precipitate of polyphenylene ether. The yield of polyphenylene ether was 97%.
Ηsp / c of this polyphenylene ether was 0.54.

[0031]

Example 2 Example 1 was repeated except that cupric bromide dihydrate was replaced by 0.0295 g (0.132 mmol) of cupric bromide. Polymerization rate is 0.5
8 mmol oxygen / min. The yield of polyphenylene ether was 97%. Further, ηsp / c of the obtained polyphenylene ether was 0.55.

[0032]

Example 3 The procedure of Example 1 was repeated except that 0.096 g (1.056 mmol) of 2-methylthioethylamine was used. The polymerization rate was 0.68 mmol oxygen / min. The yield of polyphenylene ether is 9
6%. Further, ηsp / c of the obtained polyphenylene ether was 0.55.

[0033]

Example 4 Example 4 was carried out in the same manner as in Example 1 except that the temperature of the water bath was changed to 30 ° C. The polymerization rate was 0.81 mmol oxygen / min). The yield of polyphenylene ether was 97%. Further, ηsp / c of the obtained polyphenylene ether was 0.56.

[0034]

Example 5 0.056 g of 3-methylthiopropylamine was used instead of 2-methylthioethylamine in Example 1.
(0.528 mmol) was used in the same manner as in Example 1. The polymerization rate was 1.04 mmol oxygen / min. The yield of polyphenylene ether was 97%. Ηsp / c of the obtained polyphenylene ether
= 0.56.

[0035]

Comparative Example 1 Example 1 was carried out except that 2-methylthioethylamine was used. (The polymerization rate is 0.13 mmol oxygen / min)
Met.

[0036]

According to the method of the present invention, the use of a very high activity catalyst having an improved activity requires a small amount of the catalyst. Therefore, the method is used in the step of removing the catalyst residue in the polymer. Less solvent is required. As a result, the cost of recovering the solvent is reduced, and the equipment for removing the catalyst can be reduced in size, thereby greatly simplifying the catalyst removal process.

Furthermore, the method of the present invention has very high activity and can achieve high-efficiency productivity.

Claims (5)

[Claims] 1. A copper compound and a compound represented by the following formula (1): And a thioether compound having an amino group represented by the formula: 2. A thioether compound having an amino group having 2
The catalyst for oxidative polymerization of a phenolic compound according to claim 1, which is -methylthioethylamine. 3. The thioether compound having an amino group is 3
The catalyst for oxidative polymerization of a phenolic compound according to claim 1, which is -methylthiopropylamine. 4. The catalyst for oxidative polymerization of phenolic compounds according to claim 1, wherein the thioether compound further contains an amine compound. 5. A process for producing polyphenylene ether, comprising oxidatively polymerizing a phenolic compound with oxygen in the presence of the catalyst according to claim 1. Description: