JPH0455434A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To efficiently obtain the subject substantially straight-chain polymer having a high molecular weight by carrying out oxidative coupling polymerization of diphenyl disulfides and thiophenols in the presence of an acid in two stages using a catalyst. CONSTITUTION:The objective polyarylene sulfide is obtained by carrying out polymerization reaction of diphenyl disulfides expressed by formula I (R<1> to R<8> are H, halogen, lower alkyl or lower alkoxy) and/or thiophenols expressed by formula II (R<9> to R<12> are same as R<1> to R<8>) in the presence of an acid such as a protonic acid or a proton donative substance, preferably using a vanadium- based catalyst preferably in a solvent such as nitromethane preferably at 0-40 deg.C under a pressure of oxygen in the first stage, then adding preferably hydrochloric acid-containing methanol to the resultant reaction mixture, precipitating and separating the polymer or polymer-containing substance and subsequently carrying out polymerization reaction of the aforementioned separated polymer, etc., under the same conditions as those in the first stage.

Description

DETAILED DESCRIPTION OF THE INVENTION [Industrial Field of Application] The present invention relates to a method for producing polyarylene sulfide used in electrical materials, electronic materials, coating agents, additives for molded products, and the like.

[Prior Art and Problems to be Solved by the Invention] Conventionally, polyarylene sulfides such as polyphenylene sulfide have been prepared by combining dihalogenated aromatic compounds such as p-dichlorobenzene and alkali metal sulfides such as sodium sulfide with N- It is produced by carrying out a polycondensation reaction in a polar solvent such as methylpyrrolidone at high temperature and under pressure (see Japanese Patent Publication No. 45-3368).

However, in the method described in this patent publication,
Since it is necessary to perform the process at a high temperature of 5 to 450°C and a pressure of 11,000 psi or more, it consumes a large amount of energy. Also, the by-product alkali metal salt remains in the polyarylene sulfide, which deteriorates the electrical and chemical properties of this polyarylene sulfide. There were problems such as worsening of the problem.

Furthermore, it is also known to directly obtain polyarylene sulfide by polymerizing diphenyl disulfide or thiophenol using sulfuric acid as a catalyst, but this method has the disadvantages of producing many by-products and producing a large amount of cross-linked polymer. .

Another method for obtaining polyarylene sulfide using diphenyl disulfide and thiophenol is disclosed in JP-A-63-2.
Although it is disclosed in Publication No. 13526 and Publication No. 63-213527, it is necessary to use large amounts (equimolar amounts) of expensive Lewis acids and oxidizing agents, and it is difficult to remove these Lewis acids remaining in the polymer. The problem was that large amounts of solvents and detergents were required.

Furthermore, Macromol 22.4138 (198
In 9), diphenyl disulfides are subjected to oxidative coupling polymerization in the atmosphere in the presence of an acid and a catalyst, resulting in a product that has excellent electrical and chemical properties because it does not contain impurities such as alkali metal salts. In particular, substantially linear polyarylene sulfide is obtained with little by-product of crosslinked polymer, but in this case, there are disadvantages that not only the reaction rate is slow but also the molecular weight of the obtained polymer is low.

Therefore, the object of the present invention is to provide a method for producing polyarylene sulfide which is extremely advantageous for the industry and which enables production of substantially linear polyarylene sulfide having a high molecular weight under mild conditions with good productivity. It is about providing.

[Means for Solving the Problems] In order to achieve the above object, the inventors of the present invention, as a result of extensive research, have discovered that diphenyl disulfide and/or thiophenol are used as reaction raw materials, and they are catalyzed in the presence of an acid. When producing polyarylene sulfide by oxidative coupling polymerization using It has been found that the method of carrying out the second-stage polymerization reaction using the obtained polymer or polymer-containing substance is extremely effective in achieving the object of the present invention, and based on this knowledge, the present invention has been developed. It has been completed.

That is, the present invention provides -Momonen [I] (In formula [I], R1-R8 each represent a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group, and R1-R8 are of the same type as each other. ) and/or diphenyl disulfides represented by the general formula [■ (in formula [II], R9-R12 are hydrogen atoms,
It represents a halogen atom, a lower alkyl group, or a lower alkoxy group, and R9 to R12 may be the same type or different types. ) When producing polyarylene sulfide by oxidative coupling polymerization of thiophenols represented by A method for producing polyarylene sulfide, which is characterized by separating a polymer or a polymer-containing substance from a reaction mixture and carrying out a second-stage polymerization reaction using the obtained polymer or polymer-containing substance. It is something to do.

Since the present invention is an invention of a method for manufacturing a product, the present invention will be described below as (A) 8:1 starting material (monomer), (B
) Processing conditions (polymerization conditions), (C) Target substance (polymer)
A detailed explanation will be given in this order.

(A) Starting material (monomer) The monomer used as a starting material in the method for producing polyarylene sulfide of the present invention is a diphenyl disulfide represented by - general formula CI] and/or a diphenyl disulfide represented by general formula [I [ ] It is a thiophenol.

A more detailed explanation of R1 to R12 in the general formulas [■] and [II] is as follows.

That is, specific examples of each of R1 to R12 are, for example, a hydrogen atom; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, or an iodine atom; a methyl group, an ethyl group, a propyl group, a 1-methylethyl group; , butyl group,
1-methylpropyl group, 2'' methylpropyl group, 1.1
- Lower alkyl groups such as dimethylethyl group, pentyl group, hexyl group, heptyl group, off-thyl group; methoxy group, ethoxy group, propoxy group, isopropoxy group, butoxy group, isobutoxy group, 5ec-butoxy group, ter
Examples include lower alkoxy groups such as t-butoxy, pentyloxy, and hexyloxy. Among these, hydrogen atom; methyl group, ethyl group; methoxy group, ethoxy group are preferred, and hydrogen atom, methyl group, ethyl group, etc. are particularly preferred.

Examples of the diphenyl disulfides represented by the general formula [I] include diphenyl disulfide, 2
．． 2'-dimethyldiphenyl disulfide, 3.
3'-dimethyldiphenyl disulfide, 2. 2'
, 6. 6'-tetramethyldiphenyl disulfide, 2.2', 3.3'-tetramethyldiphenyl disulfide, 2. 2', 5゜5'-tetramethyldiphenyl disulfide, 3゜3' 5
5'-tetramethyldiphenyl disulfide, 2.
2', 3. 3', 5. 5'-hexamethyldiphenyl disulfide, 2. 2',
3°3', 6.6'-hexamethyldiphenyl disulfide, 2.2', 3.3', 5.5'
6.6'-octamethyldiphenyl disulfide, 2
゜2'-Diethyldiphenyl disulfide, 3.3-diethyldiphenyl disulfide, 2.2'6.6'-tetraethyldiphenyl disulfide, 2, 2' 3
．． 3' 6. 6'-hexaethyldiphenyl disulfide, 2. 2', 3. 3', 5゜5
'6.6'-octaethyldiphenyl disulfide, 2,2'-dipropyldiphenyl disulfide, 3
, 3'-dipropyldiphenyl disulfide, 2.
2' 5. 5'-tetrapropyldiphenyl disulfide, 2.2'-dibutyldiphenyl disulfide, 2.2'-diethyldiphenyl disulfide,
2. 2'-dihexyldiphenyl disulfide, 2
．． 2'-difluorodiphenyl disulfide, 2.
2'-dichlorodiphenyl disulfide, 2.2'
-dibromodiphenyl disulfide, 2. 2'-
Short diphenyl disulfide, 3.3'-difluorodiphenyl disulfide, 3. 3'-dichlorodiphenyl disulfide, 3. 3'-dibromodiphenyl disulfide, 3. 3'-short diphenyl disulfide, 2,2'3,3'-tetrafluorodiphenyl disulfide, 2. 2' 3. 3'
-tetrachlorodiphenyl disulfide, 2. 2'
5. 5'tetrafluorodiphenyl disulfide, 2°2'5. 5'-tetrachlorodiphenyl disulfide, 2.2'6.6'-tetrafluorodiphenyl disulfide, 2. 2' 6. 6'-
Tetrachlorodiphenyl disulfide, 2. 2' 6
．． 6'-tetrabromodiphenyl disulfide, 3°3' 5. 5'-tetrafluorodiphenyl disulfide, 3. 3' 5. 5'-tetrachlorodiphenyl disulfide, 2. 2' 3. 3'
5. 5' hexafluorodiphenyl disulfide,
2゜2' 3. 3' 5. 5'-hexachlorodiphenyl disulfide, 2.2'3.3'
6.6'-hexafluorodiphenyl disulfide, 2. 2'33'6.6' -hexachlorodiphenyl disulfide, 2.2'3.3' 5.
5'6.6'-octafluorodiphenyl disulfide, 2. 2'3°3' 5. 5' 6.
6'-octachlorodiphenyl disulfide, 2.
2'-dimethoxydiphenyl disulfide, 2.2
'-jethoxydiphenyl disulfide, 2.2'
-diisopropoxydiphenyl disulfide, 2.
2'-dipropoxydiphenyl disulfide, 2
．． 2'-dibutoxydiphenyl disulfide, 2.
2' 3. 3'-tetramethoxydiphenyl disulfide, 2. 2'6゜6'-tetramethoxydiphenyl disulfide, 2, 2' 6. 6'-
Tetraethoxydiphenyl disulfide, 3.3'
-dimethoxydiphenyl disulfide, 2.2' 5
．． Symmetrical diphenyl disulfides such as 5'-tetramethoxydiphenyl disulfide; 2-methyldiphenyl disulfide, 2-ethyldiphenyl disulfide,
2-Propyldiphenyl disulfide, 2-butyldiphenyl disulfide, 2-fluorodiphenyl disulfide, 2-chlorodiphenyl disulfide, 2-methoxydiphenyl disulfide, 2,6-dimethyldiphenyl disulfide, 2.6-diethyldiphenyl disulfide, 2,6- Cyfluorodiphenyl disulfide, 2
, 3-dimethyldiphenyl disulfide, 2. 3.
5. 6-tetrafluorodiphenyl disulfide, 2
．． 3. 5. 6-tetramethyldiphenyldisulfide, 2.36-dolimethyldiphenyldisulfide,
2,6-dimethyl-2'-methyldiphenyl disulfide, 2,6-dimethyl-2'-ethyldiphenyl disulfide, 2,6-dimethyl-2'3'5'6'-tetrafluorodiphenyl disulfide, 2,6-dimethyl-2' -methoxydiphenyl disulfide, 2.6
- dinityl-2' -methyldiphenyl disulfide,
2,6-dinithyl-2'-ethyldiphenyl disulfide, 2,6-dinithyl-2. 3. 5. 6-tetrafluorodiphenyl disulfide, 2.6-dimethyl-2'6'-diethyldiphenyl disulfide, 2.6
-Simethyl-2'6'-difluorodiphenyl disulfide, 2. 3. 5. 6-tetramethyl=2'
Mention may be made of asymmetric diphenyl disulfides such as 3'5'6' -tetrafluorodiphenyl disulfide. Among these, diphenyl disulfide, 3.3', 5°5'-tetramethyldiphenyl disulfide, 2°2', 6.6'
-tetramethyldiphenyl disulfide, 2. 2'
-dimethyldiphenyl disulfide, 3.3'-dimethyldiphenyl disulfide, 2.2', 5.
5'-tetramethyldiphenyl disulfide and the like are preferred.

Examples of the thiophenols represented by -Momona [■1] include thiophenol, 2-methylthiophenol, 2-ethylthiophenol, 2-propylthiophenol, 2-(1-methylethyl)thiophenol, 2
-butylthiophenol, 2-(1-methylpropyl)
Thiophenol, 2-(2-methylbutyl)thiophenol, 2-(1,1-dimethylethyl)thiophenol, 2-pentylthiophenol, 2-hexylthiophenol, 2-octylthiophenol, 2-fluorothiophenol , 2-chlorothiophenol, 2-bromothiophenol, 2-iodothiophenol, 2-methoxythiophenol, 2-ethoxythiophenol, 2
-Propoxythiophenol, 2-butoxythiophenol, 2-sec-butoxythiophenol, 2-isobutoxythiophenol, 2-tert-butoxythiophenol, 2-pentyloxythiophenol, 2-
hexyloxythiophenol, 2-dimethylthiophenol, 26-diethylthiophenol, 2-methyl-
6-ethylthiophenol, 2,6-cyfluorothiophenol, 2-methyl-6-fluorothiophenol,
2-ethyl-6-fluorothiophenol, 2,6-dibromothiophenol, 2-methyl-6-chlorothiophenol, 2,6-dimethoxythiophenol, 2-methyl-6-methoxythiophenol, 2゜3- Dimethylthiophenol, 2,3-diethylthiophenol, 2
, 3-difluorothiophenol, 2-methyl-3-fluorothiophenol, 2-fluoro-3-methylthiophenol, 23-dimethoxythiophenol, 2-methyl-3-methoxythiophenol, 2.3-dichlorothiophenol, 2-Methyl-3-chlorothiophenol, 3-chloro-2-methylthiophenol, 2.5-
Dimethylthiophenol, 2,5-difluorothiophenol, 2,5-diethylthiophenol, 2-methyl-5-fluorothiophenol, 2-methyl-5-ethylthiophenol, 2-fluoro-5-methylthiophenol, 2゜5-Dichlorothiophenol, 2.5-dimethoxythiophenol, 2-methyl-5-chlorothiophenol, 2-methyl-5-methoxythiophenol, 2-chloro-5-methylthiophenol, 2-methoxy-5- Methylthiophenol, 2-chloro-5-fluorothiophenol, 2-ethyl-5-chlorothiophenol, 2-chloro-5ethylthiophenol, 3.5
-dimethylthiophenol, 3,5-difluorothiophenol, 3.5-dimethoxythiophenol, 3.5
-diethylthiophenol, 3,5-dichlorothiophenol, 3-methyl-5-fluorothiophenol, 3
-Methyl-5-chlorothiophenol, 3-methyl-5
-Methoxythiophenol, 2°3.54limethylthiophenol, 2. 3. 5-trifluorothiophenol, 2. 3. 5-triethylthiophenol, 2
．． 3. 5-IJ chlorothiophenol, 2-methyl-3,5-difluorothiophenol, 2. 3.
5. 6-titramethylthiophenol, 2. 3.
5.6-titrafluorothiophenol, 2. 3.
5. 6-titrachlorothiophenol, 2. 3.
5. 6-titramethoxythiophenol, 2. 3.
5. 6-titraethylthiophenol, 2,6-dimethyl-3゜5-difluorothiophenol, 2,6-
Diethyl-3,5-difluorothiophenol, 2.6
-danityl-3,5-dichlorothiophenol, 2.6
-danityl-3,5-dimethylthiophenol, 2.6
-danityl-3,5-dimethoxythiophenol, 2,
6-dimethyl-3,5-dichlorothiophenol, 2-
Examples include methyl-6-nityl-3,5-difluorothiophenol.

Among these, thiophenol, 2-methylphenol, 2-ethylthiophenol, 2-methoxythiophenol, 2,5-dimethylthiophenol, 3.5
-dimethylthiophenol, 2.5-diethylthiophenol, 3.5-diethylthiophenol, 2,6-dimethylthiophenol, 2.6-diethylthiophenol, 2゜6-dimethoxythiophenol, 2. 3.
5. 6-titramethylthiophenol and the like are preferred.

(B) Processing conditions (polymerization conditions) In the method for producing polyarylene sulfide of the present invention, diphenyl disulfides of general formula [I] and/or thiophenols of general formula [II] are treated in the presence of an acid, Oxidative coupling polymerization is carried out using a catalyst.

In this oxidative coupling polymerization, the presence of an acid is essential, and examples of such acids include protonic acids or protonic acid donors that convert into protonic acids in the presence of proton-donating substances, and known organic acids or the salt,
Inorganic acids or salts thereof, mixtures or complexes thereof, and the like can be used. Protonic acids include, for example, non-oxygen acids such as hydrochloric acid, hydrobromic acid, and hydrocyanic acid; Oxoacid; monovalent or polyvalent carboxylic acid such as acetic acid, propionic acid, butanoic acid, succinic acid, benzoic acid, phthalic acid;
Halogen-substituted carboxylic acids such as monochloroacetic acid, dichloroacetic acid, trichloroacetic acid 1, monofluoroacetic acid, difluoroacetic acid, trifluoroacetic acid; methanesulfonic acid, ethanesulfonic acid, propanesulfonic acid, benzenesulfonic acid, toluenesulfonic acid, trifluoromethanesulfonic acid Examples include monovalent or polyvalent sulfonic acids such as penzelsulfonic acid, toluenesulfonic acid, trifluoromethanesulfonic acid, and benzenedisulfonic acid.

Among these, non-volatile and highly stable strongly acidic protic acids such as sulfuric acid, trifluoroacetic acid, trifluoromethanesulfonic acid and the like are preferred, with trifluoroacetic acid being particularly preferred.

These protonic acids may be used alone or in combination or in combination of two or more.

Note that these protonic acids are considered to have a catalytic effect on oxidative coupling polymerization together with the catalyst described in detail later.

The amount of the protonic acid added to the starting material (monomer) varies depending on the type of protonic acid, whether or not it is used in combination with a protonic acid donor, the type of starting material (monomer), other polymerization conditions, etc., and is determined as appropriate. However, the amount of the protonic acid mentioned above is preferably 0.001 to 15 times the number of moles of the starting material. The reason is that if it is less than 0.001 times, the catalytic effect on oxidative coupling polymerization is small, and -
This is because if the amount exceeds 15 times, the reaction efficiency of the starting material (monomer) will decrease.

Examples of the protonic acid donor include anhydrous acids such as acetic anhydride, trifluoroacetic anhydride, and trifluoromethanesulfonic anhydride; sodium hydrogen sulfate, sodium dihydrogen phosphate, proton-retaining heteropolyacid salts, monomethyl sulfate, and trifluoromethyl sulfate. partial salts or partial esters of sulfuric acid, such as ammonium chloride, ammonium phosphate, ammonium sulfate, ammonium heteropolyacid, etc.; compounds that can act as protonic acids by dissolving in a solvent or decomposing; such as sodium benzenedisulfonate; Examples include partial metal salts of polyvalent sulfonic acids. It is considered that these protonic acid donors are converted into protonic acids in the reaction system and have a catalytic effect on oxidative coupling polymerization together with the catalyst described in detail later.

The amount of the protonic acid donor added to the starting material (monomer) varies depending on the type of protonic acid donor, whether or not it is used in combination with protonic acid, the type of starting material (monomer), other polymerization conditions, etc., and is determined as appropriate. However, the amount of protonic acid donor mentioned above is 0.00 based on the number of moles of starting material.
It is preferable to set it as 1 to 15 times. The reason is 0.00
If it is less than 1 times, the catalytic effect on oxidative coupling polymerization will be small, while if it exceeds 15 times, the reaction efficiency of the starting material (monomer) will decrease.

Among these protonic acid donors, it is particularly preferred to use acid anhydrides. The reason for this is that these anhydrous acids have the effect of removing H2O (dehydration effect), which is a by-product as the oxidative coupling polymerization progresses, and then the protonic acid produced after taking in H2O has a catalytic effect on the oxidative coupling polymerization. This is because it fulfills the following. The amount of acid anhydride that performs these two functions is 1 to 1 per mole of the starting material (monomer).
It is particularly preferable to set it to 0 times. The reason for this is that if it is less than 1 time, the dehydration effect and catalytic effect will not be sufficient, and even if it exceeds 10 times, no further dehydration effect or catalytic effect can be expected and it will become uneconomical.

Note that when focusing only on the removal of H2O produced as a by-product in oxidative coupling polymerization, a dehydrating agent such as anhydrous sodium sulfate or calcium chloride that does not affect the polymerization reaction may be used, but in this case, The use of the above-mentioned protonic acid and/or protonic acid donor is of course essential.

The catalyst used in the method for producing polyarylene sulfide of the present invention is preferably a vanadium-based catalyst,
For example, vanadyl acetylacetonate (VO (aca
c) 2) , vanadyltetraphenylporphyrin (
Examples include vanadium compounds such as VOTPP:I, vanadium trichloride oxide, vanadium acetylacetonate, and vanadium porphyrin. These vanadium-based catalysts may be used alone or in combination or in combination of two or more. The amount of the vanadium catalyst is preferably 0.0001 to 5 moles per mole of the starting material (monomer). The reason is that when the amount is less than 0.0001 mol, the polymerization rate becomes slow, while when it exceeds 5 mol,
This is because not only the cost of the catalyst increases, but also the operation for removing the catalyst from the produced polymer becomes complicated. A particularly preferable amount of the vanadium catalyst used is 0.0005 to 1 mol per 1 mol of the octogen (monomer). The catalyst used in the method for producing polyarylene sulfide of the present invention plays the role of oxygen transport and promotes oxidative coupling polymerization.

The presence of an acid and the use of a catalyst have been described above as essential conditions, but the method of the present invention has the following important essential conditions. It involves performing a polymerization reaction in two stages, separating the polymer or polymer-containing substance from the reaction mixture obtained in the first stage polymerization reaction, and using the obtained polymer or polymer-containing substance to produce the second stage. A substantially linear polyarylene sulfide having a high molecular weight is thereby obtained.

This two-step polymerization reaction in the method for producing polyarylene sulfide of the present invention will be explained in detail below.

First, the first stage polymerization reaction is carried out in the presence of the acid described above, using the catalyst described above, in the atmosphere, under a normal pressure oxygen atmosphere, under oxygen blowing, or under oxygen pressure.

In order to increase the reaction rate, it is preferable to carry out the polymerization under an oxygen atmosphere, particularly under oxygen blowing or under oxygen pressure.

Although the first stage polymerization reaction can be carried out in the absence of a solvent (bulk polymerization), it is usually desirable to carry out it in the presence of a solvent. Although any solvent can be used as long as it does not substantially eliminate the polymerization activity, it is preferable to use a solvent that can dissolve the starting material (monomer), acid, and the like.

Examples of solvents that can be used suitably include nitromethane, methylene chloride, dibromoethane, tetrachloroethane, and nitrobenzene. The solvent can also be suitably selected and used.

In the first stage polymerization reaction, these solvents may be used alone or in combination of two or more, or if necessary, aromatic hydrocarbons such as benzene, toluene, etc. It may be used by appropriately mixing with an inert solvent or the like.

The temperature in the first stage polymerization reaction can be appropriately selected within the range of -5 to 150°C. A preferred temperature is 0 to 40°C, and a particularly preferred temperature is at or near room temperature.

The time for the first stage polymerization reaction varies depending on the desired molecular weight of the polymer obtained in the first stage polymerization reaction, but is usually in the range of 0.2 to 100 hours, particularly preferably 0.2 to 100 hours. A range of 5 to 50 hours is employed.

The polymerization method in the first stage polymerization reaction is not particularly limited, and any of continuous, semi-continuous, and batch methods may be used. When using a batch method, it is desirable to stir the reaction system.

Next, the polymer or polymer-containing substance is separated from the reaction mixture obtained in the first stage polymerization reaction.

The former polymer is separated, for example, by introducing the reaction mixture into a precipitant. As a precipitant,
Although any liquid capable of precipitating the polymer when charged with the reaction mixture may be used, it is particularly preferred to use methanol, more preferably methanol containing hydrochloric acid. In addition, the latter separation of polymer-containing substances is performed in the first step.
Volatile components (
For example, the reaction is carried out by evaporating solvents, unreacted monomers, etc.) under normal pressure or reduced pressure.

If a solvent (such as benzene or dioxane) that forms an azeotrope with water contained in the reaction mixture is added to the reaction mixture prior to or during the evaporation operation, the evaporation operation can be performed efficiently. This is convenient. The separated polymer-containing substance contains non-volatile components (eg, catalyst, etc.) in addition to the polymer.

The reaction mixture obtained from the first stage polymerization reaction is poured into a precipitant to precipitate the polymer, and then the polymer is filtered to remove low polymers such as oligomer and telomer from the resulting filtrate. After separation, these low polymers may be subjected to a subsequent second stage polymerization reaction.

Next, a second stage polymerization reaction is performed using the polymer or polymer-containing substance separated after the first stage polymerization reaction. Similar to the first-stage polymerization reaction, this second-stage polymerization reaction is also carried out in the presence of the above-mentioned acid using the above-mentioned catalyst in the atmosphere, under a normal pressure oxygen atmosphere, under oxygen blowing, or under oxygen pressure. Ru. As in the first stage polymerization reaction, in order to increase the reaction rate, it is preferable to carry out the polymerization under an oxygen atmosphere, particularly under oxygen bubbling or under oxygen pressure.

In the second stage polymerization reaction, a predetermined amount of a monomer of the same kind or a different kind to the monomer constituting this polymer can be added to the polymer or polymer-containing substance obtained in the first stage polymerization reaction. By adding a predetermined amount of this monomer in the second stage polymerization reaction, there are advantages in that the reaction efficiency can be increased and a block type copolymer can be obtained.

Although the second-stage polymerization reaction can also be carried out in the absence of a solvent (bulk polymerization), it is usually preferable to carry out it in the presence of a solvent, and suitable solvents include those used in the first-stage polymerization reaction. can be mentioned.

The temperature in the second stage polymerization reaction can be appropriately selected within the range of -5 to 150°C. The preferred temperature is 0 to 80°C, and the particularly preferred temperature is room temperature or its vicinity.

The time for the second stage polymerization reaction varies depending on the desired molecular weight of the final polymer, but is usually in the range of 0.2 to 100 hours, particularly preferably 0.5 to 5 hours.
A range of 0 hours is adopted.

The polymerization method in the second stage polymerization reaction is not particularly limited, and any of continuous, semi-continuous, and batch methods may be used. When using a batch method, it is desirable to stir the reaction system.

The operation of obtaining the target substance (polymer) through the post-treatment after the second-stage polymerization reaction is performed using a well-known technique, and therefore its explanation will be omitted here.

(C) Target substance (polymer) The starting material (diphenyl disulfides of general formula [I] and/or thiophenols of general formula [II]) described in (A) above is polymerized as described in (B) above. Under the conditions,
By oxidative coupling polymerization, the target substance (polymer) is obtained from the general formula [ml R''R engineering 4 (However, R'' to R16 in the formula [ml are respectively It has the same meaning as R1 to RL2.

) A polyarylene sulfide having a main chain structure represented by the following formula, particularly a linear polyarylene sulfide with a significantly low degree of crosslinking, can be obtained.

According to the method for producing polyarylene sulfide of the present invention, the polymer or polymer-containing substance obtained in the first step polymerization reaction is separated from the reaction mixture, and then the obtained polymer or polymer-containing substance is used to prepare the polymer. By carrying out the two-step polymerization reaction, a polyarylene sulfide having a significantly higher logarithmic viscosity η1° and a high molecular weight can be obtained than polyarylene sulfide obtained by a conventional method that does not carry out such a two-step polymerization reaction.

When a single substance is used as the starting monomer, a homopolymer (homopolymer) is obtained, and when two or more copolymerizable monomers are used, a copolymer (copolymer) is obtained. can get. Furthermore, even when two or more types of monomers are used, if these monomers do not copolymerize,
A mixture of homopolymers is obtained.

The obtained polyarylene sulfide has excellent chemical properties such as heat resistance and chemical resistance, and in particular, it does not contain salts that deteriorate insulation resistance such as alkali metal salts, which have been a problem in the past, so it has excellent insulation resistance. It has outstanding electrical properties such as Therefore, it can be suitably used as equipment, parts, materials, etc. in various fields such as electronic, electrical, mechanical, and paint fields.

[Examples] The present invention will be further explained below with reference to Examples, but the present invention is not limited to these Examples.

Example 1 The first stage polymerization reaction was carried out as follows.

That is, in the atmosphere 2. 2', 6. 6'-
Tetramethyldiphenyldisulfide8. 03g:,
0.227 g of trifluoromethanesulfonic acid, 13.0 g of trifluoroacetic anhydride, and vanadyl acetylacetonate (hereinafter referred to as VQ (acac)2)
0.391 g was dissolved in 280 methylene chloride and reacted at room temperature for 20 hours. After a predetermined period of time, 3.61 g of methanol containing 2 ml of concentrated hydrochloric acid was added to the reaction mixture to precipitate a precipitate. After filtration with a glass filter, the precipitate was dried to obtain 3.15 g of a polymer (yield: 39%). Ta.

A portion of the polymer was taken and its logarithmic viscosity was reduced to 0 in methylene chloride solvent.
．． As a result of measurement at 30°C at a concentration of 5g/d1, ηlnh
=Q, 020di/g. Further, as a result of quantifying the amount of residual monomer by gas chromatography using sulfolane as an internal standard substance, it was found that the residual monomer content was 4.08%.

Next, the second stage polymerization reaction was carried out as follows. That is, the above polymer 3. oog was taken, and 0.17 g of trifluoromethanesulfonic acid was added to it.

5.54 g of trifluoroacetic anhydride and VO (acac
) 20.14 g in 70 ml of methylene chloride at an oxygen pressure of 2.
The reaction was carried out at 20° C. for 43 hours under 9 kg/c♂-G. Thereafter, the polymer precipitated and recovered in 600 methanol containing concentrated hydrochloric acid had an amount of 2.95 g (second
The yield as a step polymerization reaction is 98%), and its η1
．． ．． h was 0.047 dfl/g. Further, no residual monomer was observed.

It was thus confirmed that the polymer obtained in Example 1 had a high viscosity and a high molecular weight. It was also confirmed that there was no residual monomer.

Comparative Example 1 The reaction was carried out in the same manner as the first stage polymerization reaction of Example 1, except that the reaction time was 70 hours (unlike Example 1, the second stage polymerization reaction was not performed).

The reaction mixture obtained after the reaction was treated in the same manner as in Example 1 to obtain 4.65 g (yield: 57.9%) of a polymer. The obtained polymer has a η10. It was confirmed that it had a low viscosity of 0.020 dl/g and a low molecular weight. It was also confirmed that 3.3% of residual monomer was present.

Comparative example 2 2, 2', 6. The polymerization reaction was carried out in the same manner as the second stage polymerization reaction of Example 1, except that 3.00 g of 6'-tetramethyldiphenyl disulfide was used and the reaction time was 65 hours. However, the first stage polymerization reaction was not carried out).

The reaction mixture obtained after the reaction was treated in the same manner as in Example 1 to obtain 2.61 g (yield: 87.1%) of a polymer. It was confirmed that the obtained polymer had a low viscosity with an ηinh of 0.038 d1/g and a low molecular weight. It was also confirmed that 1.4% of residual monomer was present.

Example 2 The first stage polymerization reaction was carried out as follows.

That is, 2. 2', 6. 3.00 g of 6'-tetramethyldiphenyl disulfide, 0.17 g of trifluoromethanesulfonic acid, 4.58 g of trifluoroacetic anhydride, and 20.26 g of VO (acac) were dissolved in 100 m of methylene chloride in a sealed eggplant-shaped flask. The reaction mixture was stirred at room temperature for 16 hours. After a predetermined period of time had elapsed, 100 g of benzene was added to the reaction mixture, and the mixture was evaporated for 10 minutes using a rotary evaporator to remove volatile components to obtain a viscous liquid polymer-containing substance. When a portion of this material was taken and quantified by gas chromatography, it was found that trifluoroacetic acid and trifluoroacetic anhydride were not contained.

Next, the second stage polymerization reaction was carried out as follows. That is, 100 g of methylene chloride and 4.83 g of trifluoroacetic anhydride were added to the above polymer-containing material, dissolved again, and reacted at room temperature for 26 hours.

The resulting reaction mixture was treated in a conventional manner to obtain polymer 1.2.
2 g (yield 41%) was obtained. η1o of the obtained polymer,
, is 0.025 dl/g, and this value is the same as that of Example 2.
It was revealed that the ηlnh was higher than that of the polymer obtained in Comparative Example 3, which is different from the first stage polymerization reaction and the second stage polymerization reaction without performing the benzene addition-evaporation step. .

Comparative Example 3 As described above, the same method as Example 2 was carried out (polymerization time 42 hours) except that the benzene addition-evaporation step was not performed between the first stage polymerization reaction and the second stage polymerization reaction.
1.21 g (yield: 40%) of the polymer was obtained. The obtained polymer has a η1゜5 of 0.020dj! /g, which was lower than ηinh of the polymer obtained in Example 2, as described above.

Example 3 The first stage polymerization reaction was carried out as follows.

That is, 2. 2', 6,6'-tetramethyldiphenyl disulfide 8.98 g,) 0.51 g trifluoromethanesulfonic acid, trifluoroacetic anhydride 19
．． 4 g and 20.767 g of VQ (acac) were dissolved in 85 methylene chloride, and the oxygen gas flow rate was 35 m/mi.
The reaction was carried out at 5° C. for 200 hours under an air flow of n.

The resulting reaction mixture was treated in a conventional manner to obtain polymer 6.
38 g (yield 71%) was obtained. ηl of the obtained polymer
nh is 0.024dj2/g, and the residual monomer is 3
．． It was 5%.

Next, the second stage polymerization reaction was carried out as follows. That is, 2.03 g of the above polymer was added with 2.0 g as a monomer.
2', 6. After adding 0.21 g of 6'-tetramethyldiphenyl disulfide to obtain a mixture of polymer and monomer, this mixture was mixed with 0.08 g of trifluoromethanesulfonic acid.

4.23 g of trifluoroacetic anhydride and VO (acac
) 35 m of oxygen in methylene chloride containing 20.14 g of
The reaction was carried out at 5°C for 42 hours while blowing at a flow rate of /min. The resulting reaction mixture was treated in a conventional manner to obtain polymer 1. 78 g (yield 79%) was obtained. The obtained polymer had a high viscosity of η17 of 0.048 d1/g,
It was confirmed that it had a high molecular weight. Further, no residual monomer was detected.

Example 4 The first stage polymerization reaction was carried out as follows.

That is, the reaction mixture obtained by carrying out the same method as the first stage polymerization reaction of Example 1 was added to methanol containing concentrated hydrochloric acid, the precipitate was filtered off, and the obtained filtrate was converted into a viscous solid. After concentrating to a solid state, the oligomer was redissolved in methylene chloride, and then washed with water, washed with alkali, and washed with water in order to collect the methanol-soluble oligomer. The oligomers collected were 2
, 2'6.6' -tetramethyldiphenyl disulfide, and contained 35.4% of residual monomers.

Next, the second stage polymerization reaction was carried out as follows. That is, 3.36 g of the above oligomer, 0.16 g of trifluoromethanesulfonic acid, and 5.00 g of trifluoroacetic anhydride.
g and 20.20 g of VO (acac) were mixed in methylene chloride, stirred, and reacted at room temperature under an oxygen atmosphere for 42 hours. After a given time, the reaction mixture was precipitated by pouring it into methanol to give 2.16 g of polymer (yield 64
%) was obtained. η1 of the obtained polymer. ．． h is 0.024
d1/g, and by carrying out the second stage polymerization reaction, a polymer having a significantly higher molecular weight than the starting oligomer was obtained. The amount of residual monomer in the obtained polymer was 2.1%, which was significantly reduced compared to the amount of residual monomer in the raw material oligomer (35.4%).

[Effects of the Invention] According to the present invention, a substantially linear polyarylene sulfide having a high molecular weight can be obtained with good productivity under mild conditions. Since the obtained polyarylene sulfide does not contain impurities such as alkali metal salts, it has excellent electrical properties and chemical properties, and is suitable for use in electrical and electronic materials.

Claims (3)

[Claims] (1) General formula [I] ▲Mathematical formulas, chemical formulas, tables, etc.▼[I] (In formula [I], R^1 to R^8 are hydrogen atoms, halogen atoms, lower alkyl groups, or lower alkoxy groups, respectively. (R^1 to R^8 may be the same type or different types.) and/or the general formula [II] ▲ Numerical formula, chemical formula, There are tables, etc.▼[II] (In formula [II], R^9 to R^1^2 each represent a hydrogen atom, a halogen atom, a lower alkyl group, or a lower alkoxy group, and R^9 to R^1 ^2 may be the same type or different types.) Polyarylene sulfide is produced by oxidative coupling polymerization of thiophenols represented by ^2 using a catalyst in the presence of an acid. In the process, the polymerization reaction is carried out in two stages, the polymer or polymer-containing substance is separated from the reaction mixture obtained in the first stage polymerization reaction, and the obtained polymer or polymer-containing substance is used to perform the second stage polymerization reaction. A method for producing polyarylene sulfide, which is characterized by carrying out a stepwise polymerization reaction. (2) The method according to claim 1, wherein the separation of the polymer from the reaction mixture obtained in the first stage polymerization reaction is carried out by introducing the reaction mixture into a precipitating agent. (3) The method according to claim 1, wherein the polymer-containing substance is separated from the reaction mixture obtained in the first stage polymerization reaction by removing volatile components from the reaction mixture.