JPH01313525A - Production of polyarylene sulfide - Google Patents

Abstract

PURPOSE:To obtain a high-MW polyarylene sulfide of a low salt content in high yields by polymerizing a dihaloaromatic compound with a haloaromatic nitro compound and an alkali metal hydrosulfide in an organic polar solvent in the presence of a lithium halide. CONSTITUTION:A dihaloaromatic compound is polymerized with a haloaromatic nitro compound and an alkali metal hydrosulfide in an organic polar solvent in the presence of lithium halide. As the dihaloaromatic compound, a p- dihaloaromatic compound, particularly, a p-dihalobenzene, more particularly, p-dichlorobenzene is desirable. As the haloaromatic nitro compound, a 2,5- dichloronitrobenzene is particularly desirable. As the alkali metal hydrosulfide, sodium hydrosulfide is particularly desirable. As the polar solvent, N- methylpyrrolidone is particularly desirable.

Description

[Detailed Description of the Invention] [Industrial Application Field] The present invention relates to a method for producing polyarylene sulfide, and more specifically, the present invention relates to a method for producing polyarylene sulfide, and more specifically, a method for producing polyarylene sulfide with a high molecular weight and a low residual salt content in a high yield. The present invention relates to a method for producing polyarylene sulfide.

[Prior Art and Problems to be Solved by the Invention] Polyarylene sulfide such as polyphenylene sulfide is a thermoplastic resin that has thermosetting properties in a part of its molecules, and has excellent chemical resistance and durability over a wide temperature range. It has excellent properties as an engineering plastic, such as good mechanical properties and heat-resistant rigidity.

Conventionally, a technique for producing polyarylene sulfide such as polyphenylene sulfite from an alkali metal sulfide and a polyhalogenated aromatic compound is known (see U.S. Pat. No. 3,354,129-!I, Japanese Patent Publication No. 45th
(Refer to Publication No.-3368). However, in the above production method, a decomposition reaction of the alkali metal sulfide occurs when removing the alkali metal sulfide, so there are problems such as a decrease in the yield of polyarylene sulfide and a loss of solvent. be.

An improved method for solving these problems is to use alkali metal hydrosulfides, which can be easily dehydrated.

That is, U.S. Pat. No. 3,876,591 specification 47 discloses a method in which an alkali metal hydrosulfide is added by 0.8 to 1.5 moles to a polyhalogen aromatic compound. However, when referring to the examples in this specification, it is found that the molecular weight is small and the maximum intrinsic viscosity [ηin
Only polyarylene sulfide with a melting point of 0.04 and a melting point of 260°C or lower has been obtained. Also, U.S. Patent 3,
In No. 889.433, whether alkaline earth metal hydroxides or alkali metal carbonates are used together, or even if you refer to the examples thereof, the intrinsic viscosity [ηinh ] is 0.06 or less,
Only polyarylene sulfide with a low molecular weight, such as a melting point of 263° C. or lower, has been obtained, and such polyarylene sulfide is not suitable as an industrial material.

As an improvement to the above manufacturing method, Japanese Patent Publication No. 57 = 14698
The publication discloses a method of using an alkali metal hydrosulfide and an alkali metal hydroxide under specific conditions.

However, referring to the Examples, only polyarylene sulfide with a low viscosity of about 80 to 83 voids was obtained, and such polyarylene sulfide is not suitable for applications such as films and fibers.

Also, since this patent publication does not explicitly state that the product obtained as a result of polymerization is subjected to conventional post-treatment, U.S. Pat. No. 4,025,496 and U.S. Pat. As described in No. 4.373,091, the produced polyarylene sulfide contains ash and 5
It is estimated that about 0.00 to 6.000 ppm remains.

U.S. Pat. No. 4,025,496 discloses a method for producing polyarylene sulfide that can be easily separated by specifying the order of addition of alkali metal hydroxide. Depending on the method, the ash content in the polyarylene sulfide produced was 5,600 pp.
It is m.

Polyarylene sulfide having such a high ash content is not suitable for molding materials, films, filaments, etc., especially for electronic component applications. Furthermore, this method
Since an aqueous solution of alkali hydroxide is added after the alkali metal hydrosulfide is dehydrated, the dehydration operation is performed in two stages, which makes the dehydration operation complicated and the decomposition of the alkali metal hydrosulfide is significant. Further improvement is desired.

As a method for removing residual salts from the polyarylene sulfide produced, U.S. Pat. A method for recovering polyarylene sulfide from ash is described.

However, in this method, the alkali metal salt and the produced polyarylene sulfide are brought into contact with each other without heating after the completion of the polymerization reaction, resulting in a complicated purification operation.

As an improvement to the purification process, US patent application Ser. No. 86,111,458 discloses the use of alkali metal halides in place of alkali metal salts.

On the other hand, US Pat. No. 4,038,263 discloses the use of lithium halide as a catalyst in the reaction between an alkali metal sulfide and p-dichlorobenzene.

According to this method, high molecular weight polyarylene sulfide can be produced, and the yield of the produced polymer is as low as 70 to 85%. It was hoped that the yield could be further improved.

This invention was made based on the above circumstances.

That is, an object of the present invention is to solve the above-mentioned problems and to provide a new production method that can produce high-yield polyarylene sulfide with a low salt content and a high molecular weight.

[Means for Solving the Problems] The invention according to claim 1 for achieving the above object is a method of preparing a dihalogen aromatic compound, a halogen aromatic nitro compound, and an alkali metal hydrosulfide in an organic polar solvent. , a method for producing polyarylene sulfide, which comprises polymerizing in the presence of lithium halide, and the invention according to claim 2 provides a method for producing polyarylene sulfide, which comprises polymerizing a dihalogen aromatic compound, a halogen aromatic nitro compound, an alkali metal hydroxide, and /or an alkali metal carbonate and an alkali metal hydrosulfide in an organic polar solvent.

There is a method for producing polyarylene sulfide characterized by polymerization in the presence of lithium halide.

The invention according to claim 3 dehydrates a mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, and a lithium halide,
A method for producing polyarylene sulfide, characterized in that a polymerization reaction is carried out by bringing the obtained dehydrate, a dihalogen aromatic compound, and a halogen aromatic nitro compound into contact with each other, dehydrating the mixture of the solvent and the alkali metal hydroxide and/or the alkali metal carbonate, the alkali metal hydrosulfide and the lithium halide;
5. A method for producing polyarylene sulfide, which comprises carrying out a polymerization reaction by bringing the obtained dehydrate, a dihalogen aromatic compound, a halogen aromatic nitro compound, and newly added lithium halide into contact with each other. The invention described in 1 dehydrates a mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, a lithium halide, a dihalogen aromatic compound, and a halogen aromatic nitro compound,
A method for producing polyarylene sulfide, which is characterized in that a polymerization reaction is then carried out, and the invention according to claim 6 is a method for producing polyarylene sulfide, which is characterized in that the method according to any one of claims 1 to 5, wherein lithium halide or lithium chloride is used. This is a method for producing polyarylene sulfide.

The present invention will be further explained below.

Examples of the dihalogen aromatic compounds that can be used in the method of the present invention include 〇-dichlorobenzene, m-dichlorobenzene, P-dichlorobenzene, O
-Dihalogen-substituted benzenes such as -dibromobenzene, p-dibromobenzene, m-dibromobenzene, p-shortbenzene, l-chloro-4-bromobenzene, l-chloro-4-iodobenzene; 2.5-dichlorotoluene, 2 .5-dichloro-p-xylene, l-ethyl-2,5-dichlorobenzene, l-ethyl-2,5-dibromobenzene, l-ethyl-2-bromo-5-chlorobenzene, 1,2,4.5 -tetramethyl-3,6-dichlorobenzene, 1-cyclohexyl-2,5-dichlorobenzene, 1-phenyl-2,5-dichlorobenzene, ■-pencil-2,5-dichlorobenzene, l-phenyl-2 , 5-cyfromobenzene, 1-p-tolyl-
2,5-dichlorobenzene, 1-P-tolyl-2,5
- Dihalogen-substituted benzenes such as cyfromobenzene, 1-hexyl-2,5-dichlorobenzene, 4.4"-
Dihalogen-substituted biphenyls such as dichlorobiphenyl:
Dihalogen biphenylalkanes such as 2,2-shi(parachlorophenyl)propane; dihalogen-substituted naphthalenes such as 1,4-dichloronaphthalene, 1,6-dichloronaphthalene, and 2,6-dichloronaphthalene; and the like.

Among these, preferred are p-dihalogen aromatic compounds, further p-dihalogen benzene,
Particularly suitable is p-dichlorobenzene.

The halogen aromatic nitro compound has the following general formula (1)
, (2) and (3).

(XI is a halogen atom, a is 1 or 2, b is an integer from 1 to 5, and a+b is greater than 3 and less than 6.) [Yl is a single bond, -0- 1-S-1-so-,
-(CH2), -(tap, U is an integer of 1 or more.

), 0 and p are each O~2
is an integer, and satisfies the relationship o+p=1 or 2, C and d are integers from O to 5, and 1<c+d≦
Satisfies the relationship 10+(o+p). ] (where e is an integer of 1 or 2, f is an integer of 1 to 4, and e+f is greater than 3 and less than 5.

) Examples of the compound represented by formula (1) include 2,4-dinitrochlorobenzene and 2,5-dichloronitrobenzene.

As for the compound represented by formula (2) above.

Examples include 2-nitro-4,4'-dichlorodiphenyl ether and 3,3'-dinitro-4,4'-dichlorodiphenyl sulfone.

Examples of the compound represented by formula (3) include 2,5-dichloro-3-nitropyridine and 2-chloro-3,5-dinitropyridine.

These mono- or dihalogen aromatic nitro compounds are
One type can be used alone, or two or more types can be used in combination.

In this invention, in addition to the compound represented by the above-mentioned formula, an alkyl derivative of the compound represented by the above-mentioned formula can also be used as the mono- or dihalogen aromatic nitro compound.

Among the various mono- or dihalogen aromatic nitro compounds, 2,5-dichloronitrobenzene is particularly preferred.

Examples of the alkali metal bisulfide include lithium bisulfide, sodium bisulfide, potassium bisulfide, rubidium bisulfide, and cesium bisulfide. Preferred examples of the alkali metal hydrosulfide include lithium hydrosulfide and sodium hydrosulfide, with sodium hydrosulfide being particularly preferred. Note that these may be used alone or in combination of two or more.

In addition, in the method of this invention, the alkali metal hydrosulfide may be anhydrous, hydrated, or an aqueous mixture, or if a hydrate or an aqueous mixture is used, , f&, it is desirable to perform a dehydration operation before the reaction.

Therefore, it is preferable to use an anhydrous alkali metal hydrosulfide since no dehydration operation is required.

Examples of the alkali metal hydroxide used in this invention include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, and cesium hydroxide. It comes.

These alkali metal hydroxides can be used alone or in combination of two or more.

Furthermore, it is also possible to use alkali metal hydroxide-containing products as they are, which are obtained by the reaction of alkali metal oxides with water.

Preferred in the present invention is sodium hydroxide.

Examples of the alkali metal carbonates used in this invention include magnesium carbonate, calcium carbonate, strontium carbonate, barium carbonate, sodium carbonate, potassium carbonate, rubidium carbonate, and cesium carbonate.

These alkali metal carbonates can be used alone or in combination of two or more.

Preferred in the present invention is sodium carbonate.

As the lithium halide used in the method of the present invention, for example, lithium fluoride, lithium chloride, lithium bromide, and lithium iodide are preferable, and lithium chloride is particularly preferable. These lithium halides may be used alone or in combination of two or more.

In addition, in the method of this invention, the lithium halide is
Can it be used as an anhydride, hydrate or an aqueous mixture? If a hydrate or aqueous mixture is used, it is necessary to perform a dehydration operation before the reaction as described below. There are cases.

The polar solvents that can be used in the method of the present invention include amide compounds, lactam compounds, urea compounds, cyclic organophosphorus compounds, and the like.

Among these, specific examples of suitable solvents are:
For example, N,N-dimethylformamide, N,N-dimethylacetamide, N,N-diethylacetamide,
N,N-diethylacetamide, N,N-dimethylbenzoic acid amide, caprolactam, N-methylcaprolactam, N-ethylcaprolactam, N-isopropylcaprolactam, N-inbutylcaprolactam, N-propylcaprolactam, N-butylcaprolactam, N −
Cyclohexylcaprolactam, N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone, N-isopropyl-2-pyrrolidone, N-isophthyl-2-pyrrolidone, N-propyl-2-pyrrolidone, N-butyl-2-pyrrolidone Pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-
Methyl-3-methyl-2-pyrrolidone, N-cyclohexyl-2-pyrrolidone, N-methyl-3-methyl-2-
Pyrrolidone, N-methyl: l, 4,5. - Trimethyl-2-pyrrolidone, N-methyl-2-piperitone, N
-ethyl-2-piperitone, N-isopropyl-2-piperitone, N-methyl-6-methyl-2-piperidone,
N-methyl-3-ethyl-2piperitone, N-methyl-
2-oxo-hexamethyleneimine, N-ethyl-2-
Oxo-hexamethyleneimine, hexamethyl phosphate triamide, hexaethyl phosphate triamide, tetramethyl urea, 1,3-dimethylethylene urea, 1,3-dimethylpropylene urea, 1-methyl-1-year-old xosulfolane, 1- Examples include ethyl-1-oxosulfolane, l-phenyl-1-oxosulfolane, l-methyl-1-oxophosphane, ■-pro-1-oxophosphane, 1-phenyl-1-oxophosphane, etc. .

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

Furthermore, among the above-mentioned various polar solvents, N-alkyl lactams, N-alkylpyrrolidone, and hexaalkylphosphoric triamides are preferred, and N-methylpyrrolidone is particularly preferred.

In the method of the present invention, a dihalogen aromatic compound, a halogen aromatic nitro compound, and an alkali metal hydrosulfide can be polymerized in an organic polar solvent in the presence of lithium halide. Producing polyarylene sulfide by polymerizing a dihalogen aromatic compound, a halogen aromatic nitro compound, and an alkali metal hydroxide, even if they are added to the organic polar solvent or brought into contact in the organic polar solvent in such an order. The preferred embodiments are as follows.

First, a dihalogen aromatic compound, a halogen aromatic nitro compound, an alkali metal hydroxide and/or an alkali metal carbonate, and an alkali metal hydrosulfide are polymerized in an organic polar solvent in the presence of lithium halide. (Claim 2).

In this case, a mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, and a lithium halide is dehydrated, and the resulting dehydrate is combined with a dihalogen aromatic compound and a halogen aromatic nitro compound. It is preferable to carry out the polymerization reaction by contacting with (Claim 3).

Further, in the dehydration, a part of lithium halide is used, and a mixture of part of the lithium halide, an organic polar solvent, an alkali metal hydroxide, and/or an alkali metal carbonate and an alkali metal hydrosulfide is dehydrated. The polymerization reaction may be carried out by bringing the obtained dehydrate, the remaining lithium halide, the dihalogen aromatic compound, and the halogen aromatic nitro compound into contact (Claim 4).

Optionally, the mixture of organic polar solvent, alkali metal hydroxide and/or alkali metal carbonate, alkali metal hydrosulfide, lithium halide, dihalogen aromatic compound, and halogen aromatic nitro compound is dehydrated and then subjected to a polymerization reaction. (Claim 5).

Furthermore, lithium chloride may be used in these polymerization reactions (Claim 6).

Dehydration can be carried out by azeotropic distillation. Further, dehydration is preferably carried out under normally used conditions in an inert gas such as a nitrogen stream, but depending on the situation, it may be carried out under reduced pressure conditions or under pressurized conditions.

During dehydration, the blending ratio (molar ratio) of the lithium halide (A) and the hydrated alkali metal hydrosulfide (B) is usually desirably as follows.

That is, the molar ratio of (A) JjE minutes/(B) Ji minutes is.

It is 0.3-2.0, preferably 0.5-1.8. If this molar ratio is less than 0.3, it may not be possible to achieve the desired high molecular weight of the polyarylene sulfide, and it may not be possible to reduce the salt content remaining in the polymer.

In addition, if the molar ratio exceeds 2.0, polymer precipitation occurs early during polymerization, making the polymerization operation difficult, and it may become impossible to achieve a high molecular weight of polyarylene sulfide. .

The blending ratio (molar ratio) of the alkali metal hydroxide (C) and the alkali metal hydrosulfide (B) during dehydration is as follows:
Generally, it is preferable to do the following:

That is, the molar ratio of component (C)/component (B) is 0.8
-1.5, preferably 0.8-1.3. If this molar ratio is less than 0.3, the amount of decomposed alkali metal hydroxide may increase, and if the molar ratio is less than 1.
If it exceeds 5, the addition of the alkali metal hydroxide will not have any effect, and the organic polar solvent may deteriorate more severely.

When the alkali metal carbonate is used instead of the alkali metal hydroxide, the alkali metal carbonate (D
) and alkali metal hydrosulfide (B) (mole ratio)
is the same as the blending ratio (molar ratio) of the alkali metal hydroxide (C) and the alkali metal hydrosulfide (B).

When the alkali metal hydroxide and alkali metal carbonate are used together, the ratio of the total number of moles of the alkali metal hydroxide and alkali metal carbonate to the number of moles of the alkali metal hydrosulfide is: It is preferable to adjust the mixing ratio (molar ratio) of the alkali metal hydroxide (C) and the alkali metal hydrosulfide Th (B) to be the same.

During the polymerization reaction, the blending ratio of each of the components described above is usually desirably as follows.

That is, the molar ratio of the dihalogen aromatic compound (E) and the alkali metal hydrosulfide (B) [(E)/(B)
] is usually 0.8 to 1.5.

Preferably it is 0.9 to 1.3. Since the reaction between the dihalogen aromatic compound (E) and the alkali metal hydrosulfide Th (B) is an equimolar reaction, it is usually set within the above range, or if the molar ratio is less than 0.8, it is industrially difficult. Not only may it become impossible to obtain useful polyarylene sulfide, but also thiophenols may be produced as by-products.

The blending molar ratio of the halogen aromatic nitro compound (F) and the dihalogen aromatic compound (E) [(F) / (E
) ] is usually 0.0001 to 0.05,
Preferably it is o,oot~0.03. If the molar ratio is smaller than 0.003, it may be impossible to achieve polymerization of polyarylene sulfide, and if the molar ratio is larger than 0.05, gelation may occur during polymerization, resulting in poor molding. Sometimes it is not possible to produce usable polyarylene sulfide.

The amount of the organic polar solvent used may be an amount sufficient to allow the reaction to proceed smoothly. In normal cases, it is sufficient to use the organic polar solvent in an amount of 180 to 1,000 g per mol of the alkali metal hydrosulfide (B).

The polymerization reaction is usually carried out at a temperature of 180 to 330°C, preferably 210 to 290°C. If the reaction temperature is lower than 180°C, the speed of the polymerization reaction will not be sufficient, while if it is higher than 330°C, side reactions may be induced or the yield of polyarylene sulfide may be reduced.

The reaction pressure of the polymerization reaction is not particularly limited or is usually
The autogenous pressure of the polymerization reaction system such as the solvent is ~10 kg/cm2 (absolute pressure).

The polymerization reaction may be performed in an atmosphere of an inert gas such as nitrogen, carbon dioxide, or water vapor.

The reaction time of the polymerization reaction is usually within 20 hours, particularly within 0.1 to 8 hours.

After the polymerization reaction is complete, the polyarylene sulfide can be separated directly from the reaction solution by standard methods, e.g. by filtration or centrifugation, or alternatively, e.g.
Alternatively, it can be obtained by diluting it, adding an acid, and then fractionating it from the reaction solution.

The filtration step is generally followed by a water wash to remove any inorganic components that may adhere to the polymer, such as alkali metal sulfides and alkali hydroxides. In addition to or after this washing step, washing or extraction with other washing solutions such as acetone or methanol may also be carried out to remove the solvent from the smooth reaction vessel, followed by washing as described above. The polymer can also be recovered by doing so.

The content of salts such as common salt remaining in the polyarylene sulfide recovered in this way is significantly lower than that of polyarylene sulfide produced by the conventional method using alkali metal sulfide as the sulfur source, so it is moisture resistant. Since the polyarylene sulfide has high electrical insulation properties, it can be molded and processed without any particular desalination treatment, and can be suitably used in the electrical and electronic fields. In addition to or after.

It is also possible to further reduce the concentration of salts such as common salt in the resin by performing various desalting treatments.

When the polyarylene sulfide obtained by the method of this invention is molded into various products, other polymers, pigments and fillers, such as graphite, metal powder, glass powder,
It can be mixed with quartz powder or glass fibers or with additives customary for polyarylene sulfides, such as customary stabilizers or mold release agents.

The polyarylene sulfide such as polyphenylene sulfite obtained by the method of the present invention is white and has high purity, and in addition, it can be produced in high yield as a high molecular weight resin with small melt flow. It can be used as a matrix resin for various molded products and composites, and can also be used to make various molded products, films, m-fibers, etc. 1. It can be suitably used for mechanical parts as well as electrical and electronic parts. It is an excellent engineering plastic.

[Example] (Example 1) Sodium hydrosulfide (content 71%, 29% is water) 42.8
g (0,543 mol), pelleted sodium hydroxide 21.7 g (0,543 mol), lithium chloride 23
．． 0 g (0,543 mol) and 297 m of N-methylpyrrolidone were charged into a 1M autoclave, and the inside of the autoclave was purged with nitrogen.

The contents of the autoclave were heated to 120 ml under a nitrogen stream.
After heating for 1 hour at 150°C, it was subsequently dehydrated by distillation at 150°C for 1 hour.

105 mu of a mixture of N-methylpyrrolidone and water was distilled off.

After cooling the internal temperature of the autoclave to 100°C, p-
79.5 g (0.54 mol) of dichlorobenzene and 2,
5-dichloronitrobenzene 0.31g (0,001
A solution obtained by dissolving 6 mol) in N-methylpyrrolidone roomM was added to the dehydrated product, the autoclave was sealed, and the temperature was raised to 260°C to conduct a polymerization reaction for 3 hours.

After the reaction is complete, cool to around room temperature, open the lid, take out the slurry-like reaction product, take this into account, separate the granular polymer, and wash it twice with a single stream of water. ,
It was further washed with acetone and then dried. The amount of polyphenylene sulfide obtained was 54.5 g (yield 93.0%; based on p-dichlorobenzene). The molecular weight of the obtained polyphenylene sulfide was determined at 206°C using α-chlornaphthalene as a solvent at a concentration of 0.4 g/di.
The intrinsic viscosity [ηinh] was measured at a temperature of 0.
38, and as a result of quantifying the sodium ion in the polyphenylene sulfite by atomic absorption method, it was found to be 81pp.
There was m.

(Example 2) The amount of lithium chloride used was 12.0g instead of 23.0g.
Dehydration was carried out in the same manner as in Example 1 except that 11.02 g of lithium chloride was added before charging p-dichlorobenzene.
The procedure was carried out in the same manner as in Example 1 except that .

As a result, 9 g (yield 92%) of polyphenylene sulfite was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity [ηinh] was 0.35,
The sodium ion content was 88 ppm.

(Comparative Example 1) Same as Example 1 except that 91.29 g (0°543 mol) of sodium chloride/Itsuki salt, 23.2 g (0,543 mol) of lithium chloride, and 297 mJl of N-methylpyrrolidone were used. After dehydration, 145 mJQ of a mixture of N-methylpyrrolidone and water was distilled off.

Thereafter, the same procedure as in Example 1 was carried out, except that after cooling to 100° C., 79.8 g (0,543 mol) of p-dichlorobenzene was dissolved in 103 mJL of N-methylpyrrolidone and reacted.

As a result, 51.0 g (yield 87%) of polyphenylene sulfite was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity [ηinh] was 0.28.
The sodium ion content was 1105 pp.

(Comparative Example 2) In Comparative Example 1, p-dichlorobenzene was 79.8
p-dichlorobenzene 79.5g (0,
541 mol) and dichloronitrobenzene 0.313 g
The same procedure as in Comparative Example 1 was carried out except that (0,0016 mol) was added.

As a result, 49.3 g (yield 84%) of polyphenylene sulfite was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity [ηinh] was 0.32.
The sodium ion content was 220 ppm.

(Comparative Example 3) The same procedure as in Example 1 was carried out except that lithium chloride was not added.

This comparative example corresponds to the example described in Japanese Patent Publication No. 57-14698.

In this comparative example 3, 57.3 g (yield 98%)
Polyphenylene sulfite was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity was found to be
．． 22, and the sodium ion content is 3,150p.
It was pm.

(Comparative Example 4) 79.8 g of p-dichlorobenzene (0.54 g) without using lithium chloride and p-dichloronitrobenzene
The same procedure as in Example 1 was carried out except that 3 mol) was used.

As a result, 57.3 g (98% yield) of polyphenylene sulfite was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity was 0.17.
The sodium ion content was 2.980PPm.

(Example 3) In the above Example 1, p-dichlorobenzene 67.8
(0,461 mol) and 0.267 g (0,0014 mol) of 2,5-cycloo-trohenzene,
The same procedure as in Example 1 was carried out except that the pellet-shaped sodium hydroxide was not used.

As a result, 13.6 g (yield 27%) of polyphenylene sulfide was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity [ηinh] was 0.06.
The sodium ion content was 800 ppm.

The polyphenylene sulfide obtained in this example has a higher molecular weight than any of the examples described in US Pat. No. 3,869,433 and US Pat. No. 3,876,591.

(Example 4) In Example 1, p-dichlorobenzene 69.1
8 (0,471 mol) and 2,5-dichlorobenzene: 10.27 g (0,0014 mol),
The same procedure as in Example 1 was carried out except that 28.8 g (0,272 mol) of sodium carbonate was used in place of 21.7 g of sodium hydroxide in pellet form.

As a result, 27.1 g (yield 53%) of polyphenylene sulfide was obtained, and as a result of measurement in the same manner as in Example 1, the intrinsic viscosity [ηinh] was 0.09, and the sodium ion content was 1. It was 1100pp.

The polyphenylene sulfite obtained in this example is superior to the polyphenylene sulfide described in US Pat. No. 3,869,433.

(Example 5) In this example, the amount of decomposition of sodium hydrosulfide was investigated.

Sodium hydroxide and sodium bisulfide 42.83g (0,543 mol) and lithium chloride 23g in the amounts shown in Table 1
．． 2g (0,543 mol) and N-methylpyrrolidone 2
The amount of decomposed sodium hydrogen sulfide was determined by weighing the amount of hydrogen sulfide produced when 97 ml was charged into an autoclave and distilled in the same manner as in Example 1. The results are shown in Table 1.

The amount of hydrogen sulfide produced was determined by trapping the generated gas with an alkali and using iodometry.

Table 1 Added amount of NaOH Decomposed amount of Na5H (g)
(:) 0 14.9 0, 5 9.6 0.65 5.1 From the results shown in Table 1, if sodium hydroxide is added before dehydration, the amount of sodium hydrosulfide decomposed can be reduced by at least 1
It can be seen that this is advantageous for polymerization reactions.

[Effects of the Invention] According to the method of the present invention, polyarylene sulfide having a high molecular weight and a lower salt content than in polyarylene sulfide obtained by conventional post-treatment can be produced in high yield. The polyarylene sulfide obtained by the method of the present invention has a low salt content and high whiteness.

Patent applicant: Idemitsu Petrochemical Co., Ltd.

Claims (6)

[Claims] (1) A method for producing polyarylene sulfide, which comprises polymerizing a dihalogen aromatic compound, a halogen aromatic nitro compound, and an alkali metal hydrosulfide in an organic polar solvent in the presence of lithium halide. (2) Polymerizing a dihalogen aromatic compound, a halogen aromatic nitro compound, an alkali metal hydroxide and/or an alkali metal carbonate, and an alkali metal hydrosulfide in an organic polar solvent in the presence of lithium halide. A method for producing polyarylene sulfide, characterized by: (3) A mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, and a lithium halide is dehydrated, and the resulting dehydrate, dihalogen aromatic compound, and halogen aromatic nitro compound are obtained. 1. A method for producing polyarylene sulfide, which comprises carrying out a polymerization reaction by contacting with. (4) A mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, and a lithium halide is dehydrated, and the resulting dehydrate, dihalogen aromatic compound, and halogen aromatic nitro compound are obtained. A method for producing polyarylene sulfide, which comprises carrying out a polymerization reaction by contacting lithium halide with newly added lithium halide. (5) A mixture of an organic polar solvent, an alkali metal hydroxide and/or an alkali metal carbonate, an alkali metal hydrosulfide, a lithium halide, a dihalogen aromatic compound, and a halogen aromatic nitro compound is dehydrated, and then a polymerization reaction is performed. A method for producing polyarylene sulfide, characterized by carrying out the following steps. (6) Claim in which the lithium halide is lithium chloride (
1) The method for producing polyarylene sulfide according to any one of claims (5).