JPH03281530A - Production of polycyanoaryl ether - Google Patents

Abstract

PURPOSE:To obtain the title polymer useful as an electronic device, etc., having excellent industrial workability in reacting a dichlorobenzonitrile with resorcinol and an alkali metallic salt, by carrying out the reaction in the presence of an alkali salt of oxalic acid. CONSTITUTION:In obtaining a polycyanoaryl ether by reacting a dichlorobenzonitrile (e.g. 2,6-dichlorobenzonitrile) with resorcinol and an alkali metallic salt (e.g. lithium carbonate) and a solvent (e.g. DMF), and then reacting the reaction product with difluorobenzonitrile in the presence of a solvent. The reaction is done in the presence of an alkali salt of oxalic acid (e.g. sodium oxalate; the amount used is preferably 0.05-5% based on the polymerization solvent) to give the objective polymer.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing polycyanoaryl ether, and more specifically, to an efficient method for producing polycyanoaryl ether useful as a material for electronic equipment, electrical equipment, mechanical parts, etc. Regarding the manufacturing method.

[Prior art and problems to be solved by the invention] Polycyanoaryl ether produced from dichlorobenzonitrile and resorcinol has been known as a high-performance engineering plastic (Japanese Unexamined Patent Publication No. 62
(Refer to Publication No.-223226). Furthermore, as a method for obtaining higher molecular weight polycyanoaryl ether, a method has been proposed in which dichlorobenzonitrile 2 resorcinol and an alkali metal salt are reacted, and the reaction product is further reacted with difluorobenzonitrile (JP-A-Sho 6
3-189435).

However, although the polycyanoaryl ether produced by such conventional methods has a relatively high molecular weight, the polymerization process during production requires a long time and the productivity is extremely low. Furthermore, since a considerable amount of oligomers, inorganic salts, etc. remain in the polymer, there are problems in its use as a material for various mechanical parts.

Therefore, the present inventor conducted extensive research in order to solve the problems of the above technology and develop a method for efficiently producing polycyanoaryl ether having a high molecular weight and a low impurity content in a short period of time.

[Means for Solving the Problems] As a result, it has been found that the objects can be achieved by allowing an alkali metal oxalate salt to be present in the reaction system during the polymerization reaction. The present invention was completed based on this knowledge.

That is, the present invention uses dichlorobenzonitrile.

A step of reacting resorcinol and an alkali metal salt in the presence of a solvent (hereinafter referred to as the first step), then a step of reacting the obtained reaction product with difluorobenzonitrile in the presence of a solvent (hereinafter referred to as the second step) The present invention provides a method for producing a polycyanoaryl ether, which is characterized in that the reaction is carried out in the presence of an alkali metal oxalate salt.

The raw materials for the first step of the present invention are dichlorobenzonitrile, resorcinol and an alkali metal salt.

Examples of dichlorobenzonitrile include 2,6-cyclobenzonitrile; 2,4-dichlorobenzonitrile or a mixture thereof. Further, the alkali metal salt reacts with resorcinol in the reaction system to form an alkali metal salt of resorcinol, thereby activating the reaction.

Examples of the alkali metal salts include alkali metal carbonates, hydrogencarbonates, and hydroxides. Specifically, lithium carbonate, sodium carbonate 7 potassium carbonate, cesium carbonate, lithium hydrogen carbonate, sodium hydrogen carbonate, and potassium hydrogen carbonate.

Cesium bicarbonate, and even lithium hydroxide.

These include sodium hydroxide, potassium hydroxide, and cesium hydroxide, with sodium hydrogen carbonate and sodium carbonate being particularly preferred.

In the reaction, the amounts of dichlorobenzonitrile, resorcinol and alkali metal salts to be used may be determined as appropriate without particular limitation, but usually 0.95 to 1.03 (molar ratio) of dichlorobenzonitrile to resorcinol, preferably 0.98 to 1.01 (molar ratio), 1.0 to 3.0 (molar ratio) in the case of alkali metal salts, preferably 1.0
~2.0 (molar ratio), 2.0 for alkali metal hydrogen salts.
0 to 6.0 (molar ratio), preferably 2.0 to 4.0 (molar ratio).

When the amount of dichlorobenzonitrile used is outside the above range, there is a disadvantage that the achieved molecular weight is small.

Furthermore, if the amount of the alkali metal salt or alkali metal hydrogen salt used is less than the above range, there will be a problem that the achieved molecular weight will be small, whereas if it exceeds the above range, there will be a disadvantage that the molecular weight will decrease during polymerization.

In the first step of the method of the present invention, the above three components are subjected to a polycondensation reaction in a solvent in the presence of an alkali metal oxalate.

The presence of the alkali metal oxalate salt increases the rate of the polymerization reaction and also suppresses the decomposition reaction in the polymerization solvent. Therefore, high molecular weight products can be produced in a short time. Here, the alkali metal oxalate is sodium oxalate.

Examples include potassium oxalate and hydrates thereof.

Further, as the solvent used in the polymerization, that is, the polycondensation solvent, any aprotic polar solvent can be used without particular restriction. Specifically, N.

N-dimethylformamide (DMF); N N dimethylacetamide (DMAc); N-methyl-2-pyrrolidone (NMP); N,N'-dimethylimidazolidinone (DMI); hexamethylphosphoramide (HM
Amide compounds such as PA); dimethyl sulfoxide (
Examples include sulfoxide compounds such as DMSO; sulfone compounds such as diphenylsulfone and sulfolane; NMP and DMI are particularly preferred.

Furthermore, the amount of polymerization solvent used is preferably such that the polymer concentration in the solvent is usually 0.5 to 2.5 moles/step.

In the polycondensation reaction, the amount of alkali metal oxalate to be used may be appropriately selected depending on the type of raw materials, reaction conditions, etc., but is in the range of o, oi to io% relative to the commonly used polymerization solvent.
, preferably 0.05 to 5%. Here, if the amount of alkali metal oxalate used is less than 0.01%, the purpose of use cannot be sufficiently achieved.

In addition, this polycondensation reaction is carried out under appropriate conditions, usually 160 to 3
00°C1 preferably in the temperature range of 180 to 250°C,
It may be carried out for 0.5 to 7 hours, preferably 1 to 5 hours. Furthermore, this reaction may be carried out under normal pressure or under slightly increased pressure. Furthermore, it is more effective to carry out the reaction under an inert gas atmosphere such as argon gas or nitrogen gas.

In addition, in the case of the said polycondensation reaction, a molecular weight regulator can be added as needed. Examples of molecular weight modifiers that can be used include monohalogenobenzonitrile, monophenol, and the like.

Moreover, the amount to be used may be appropriately determined in relation to the molecular weight of the target polymer.

In the first step, dehydration treatment may be performed before the heating reaction. This treatment is carried out by a conventional method, such as dehydration using a solvent that is azeotropic with the produced water or dehydration using an inert gas. The azeotropic solvents used here include toluene and chlorobenzene.

Examples include anisole.

Then, in the second step, the reaction product obtained in the first step described above is further reacted with difluorobenzonitrile in the presence of a solvent. Here, difluorobenzonitrile is
It functions as a main chain extender, and therefore, a polycyanoaryl ether with a high molecular weight can be produced by this reaction. Furthermore, in the second step of the present invention, it is necessary to carry out the reaction in the presence of an alkali metal oxalate salt in the reaction system, as in the first step. Here, the alkali metal oxalate salt and the solvent are the same as those described above.

In the second step, the amount of difluorobenzonitrile used is 0.001 to 0 relative to resorcinol in the first step.
．． 05 (molar ratio), preferably 0.005 to 0.03 (
molar ratio). Here, if the amount of difluorobenzonitrile used is outside the above range, it is not preferable because there is a problem that the achieved molecular weight is small.

The reaction in the second step can usually be carried out by adding difluorobenzonitrile to the reaction system in the first step. Therefore, the same solvent as in the first step may be used. In addition, the alkali metal oxalate does not need to be added in the second step if it is sufficiently present in the reaction product obtained in the first step, but it may be added in the required amount if necessary. .

The conditions for the reaction in the second step of the present invention are not particularly limited and may be appropriately selected depending on various circumstances, but usually the reaction conditions may be within the range of the reaction conditions in the first step.

Then, if necessary, a terminal terminator is added to terminate the polymerization reaction. Various types of terminal capping agents can be used; specifically, monohydric phenols such as phenol, cumylphenol, methoxyphenol, and cyanophenol; methyl chloride, chlorobenzene, fluorobenzene, chloropenzezophenone, Monovalent halides such as fluorobenzezophenone; polyhalogenated benzonitriles such as dichlorobenzonitrile and dichlorobenzonitrile; and the like.

The amount of the terminal capping agent to be used is determined depending on the degree of polymerization, viscosity, etc. of the desired product, but is usually 0.005 to 0.1 (molar ratio), preferably 0.005 to 0.1 (molar ratio) to the raw material resorcinol. 01 to 0.05 (molar ratio).

By purifying the reaction product thus obtained, the desired high molecular weight polycyanoaryl ether can be obtained. This purification step may be carried out using a simple procedure. Specifically, the following method may be used.

First, after the reaction is completed, the polymerization solvent is diluted by adding 0.5 to 3 times as much polymerization solvent as the polymerization solvent. This is because the viscosity of the polymerization solution is reduced, and operability can be improved. Further, a particulate solvent having a solvent/water volume ratio of 9515 to 30/70 is added in an amount of 0.5 to 3 times the amount of the polymerization solvent. By adding a granulation solvent, the average particle size of the polymer obtained as a dry powder can be adjusted to 50 to 200 μm. Furthermore, the product is washed with a washing solvent. This operation mainly removes oligomers and can reduce the content of impurities. As this washing solvent, a mixed solvent having a polymerization solvent/water ratio of 10010 to 30/70 is used, and the amount added is preferably 0.5 to 5 times the amount of the reaction polymerization solvent. Polycyanoaryl ether is then obtained by washing with water and drying. Washing is usually carried out with water, but neutralization treatment using an inorganic acid such as hydrochloric acid or an organic acid such as oxalic acid may also be performed.

The polycyanoaryl ether produced in this way is a high molecular weight polymer with a concentration of 0.2 g/a in p-chlorophenol solvent and a reduced viscosity η3.7c of 1.2 at 60°C. That's all.

In addition, the efficiency is high (due to the purification, the residual oligo 7- is 1.5% tJi, and the residual alkali metal salt amount is extremely low, less than 20 ppm).

〔Example〕

Next, the present invention will be explained in more detail with reference to Examples and Comparative Examples.

Example 1 Stirring device, inert gas blowing pipe, thermocouple, Dean-S
In a separable flask equipped with a tark trap, 22.02 g of resorcinol, 34.35 g of 2,6-cyclopenzonitrile, 23.32 g of sodium carbonate,
Sodium oxalate 1.0g (0.5% by weight based on NMP), N-methyl-2-pyrrolidone (NMP) 200g
d was added, the temperature was raised to 195°C while blowing argon gas, and the water produced was dehydrated by azeotropy with toluene for 1 hour, followed by reaction at 200°C for 1 hour.

Next, 0.35 g of 2,6-dichlorobenzonitrile was added as a main chain extender to the NMPI! To? The diluted solution was added, and a polycondensation reaction was carried out at 200°C. reaction time 2
After 3 hours, 4 hours, and 5 hours, a small amount of the polymerization solution was sampled and the reduced viscosity was measured. The collected polymerization solution was washed with water, dried at 130°C for 12 hours, and then its reduced viscosity was measured in a P-chlorophenol solvent at 1°C, 2g/shaft, and 60°C. The results are shown in Table 1.

Examples 2 to 4 The same operations as in Example 1 were performed except that the type and amount of oxalate was changed as shown in Table 1. Table 1 shows the results.
Shown below.

Example 5 After starting polycondensation under the same polymerization conditions as in Example 1, the temperature was raised to 195°C, the produced water was dehydrated by azeotropy with toluene for 1 hour, and then the reaction was carried out at 200°C for 1 hour. Then, the main chain extender 2,6-dichlorobenzonitrile
．． A solution of 28 g dissolved in NMP2d was added to the polymerization solution, and the reaction was further carried out at 200"C for 2 hours. Then, 0.2 g of 2.6-dichlorobenzonitrile was added as a terminal capping agent.
A solution in which 8 g of NMP2d was dissolved was added to the polymerization solution, and 2
Terminal termination treatment was performed by reacting at 00°C for 30 minutes. No change was observed in the reduced viscosity measured before and after addition of the terminal capping agent, confirming that the molecular weight was regulated by terminal capping.

After the reaction is complete, add NMP at room temperature to the polymerization solution at a temperature of 200°C.
140d was added for 5 minutes to dilute. The liquid temperature at this time was 170°C. Next, a mixed solvent of NMP/water (160d/40d) was added as a particle forming solvent over 10 minutes to obtain a slurry of polycyanoaryl ether. The slurry temperature at this time was 130°C. The resulting slurry was filtered and the cake was dissolved in NMP/water (430d/
110d) Washed once with mixed solution to remove oligomers.

After that, water 600Ild! The sample was heated and washed once with an aqueous solution containing 4 g of oxalic acid dihydrate and 7 times with 600% water for 10 minutes, and then dried in a vacuum dryer overnight.

The above operations yield a dry powder (average particle size: 100 μm).
was gotten. Polymer yield 91%, reduced viscosity 1.22
d/g, residual sodium 5 ppm + residual oligomer 0.
It was 8% by weight. The results are shown in Table 1.

The method for measuring the residual amount of each component is as follows.

・Sodium: Atomic absorption spectrometry ・Oligomer m: High performance liquid chromatograph method (NN-dimethylformamide extraction) Example 6 Same as Example 5 except that 1.0 g of potassium oxalate was used instead of sodium oxalate. The same operation as in Example 5 was performed.

The yield of the obtained polymer was 91%, and the reduced viscosity was 1.20 d1.
/g, residual sodium 9 ppm, residual oligomer 0.
It was 9% by weight. Incidentally, after 2 hours, 3 hours, 4 hours, and 5 hours of reaction time with the main chain extender, a small amount of the polymerization solution was sampled and the reduced viscosity was measured. The results are shown in Table 1.

Example 7 The reaction was carried out in the same manner as in Example 5, the main chain was extended, 2 terminal terminations were performed, 1 particle was generated, and the oligomer was removed.
P/water (430/110M1) mixed solution at 110°C1
The oligomers were further removed by washing for 30 minutes. Then,
After neutralizing with hydrochloric acid and washing with water, it was dried at 130°C for 12 hours to obtain a dry powder.

The yield was 90%, the reduced viscosity was 1.20 dl/g, the residual sodium was 4 ppm, and the residual oligomer was 0.1% by weight.

The results are shown in Table 1.

Comparative Example 1 In Example 1, polymerization was carried out without adding sodium oxalate, and after one polymerization was completed, the solution was directly cooled and solidified. The solidified product was pulverized using a pulverizer in 1,000 ml of water to obtain a slurry. Thereafter, water washing and drying were performed in the same manner as in Example 1.

The yield of the obtained polymer after drying is 100%, the reduced viscosity t
, 09 dl/g, residual sodium 25 ppm, and residual oligomer 5% by weight. Incidentally, after 2 hours, 3 hours, 4 hours, and 5 hours of reaction time with the main chain extender, a small amount of the polymerization solution was sampled and the reduced viscosity was measured. The results are shown in Table 1.

Comparative Examples 2 to 4 The same operations as in Example 1 were performed except that oxalic acid was used instead of sodium oxalate. The results are shown in Table 1.

(The following is a blank space) Table 1 (Effects of the invention) As described above, according to the method of the present invention, the presence of oxalate in the reaction system increases the reaction rate and suppresses the decomposition reaction. A high molecular weight polycyanoaryl ether with a reduced viscosity of 1.2 or more can be produced efficiently in a short time.

In addition, the polycyanoaryl ether obtained has an extremely small amount of impurities such as oligomers because the reaction proceeds efficiently, and most of these impurities can be removed by a simple purification process.

Therefore, since the polycyanoaryl ether produced by the method of the present invention is of high quality, it is expected to be widely used as a material for various mechanical parts.

Claims (1)

[Claims] (1) Production of polycyanoaryl ether, which consists of a step of reacting dichlorobenzonitrile, resorcinol, and an alkali metal salt in the presence of a solvent, and then a step of reacting the obtained reaction product with difluorobenzonitrile in the presence of a solvent. A method for producing polycyanoaryl ether, characterized in that the reaction is carried out in the presence of an alkali metal oxalate salt.