KR102291475B1 - Method for for preparing of polyphenylene sulfide - Google Patents

Abstract

The present invention relates to a method for producing polyphenylene sulfide. According to the present invention, after the polymerization reaction is completed and before the washing step, an acid is added in an amount equal to or greater than the equivalent sum of unreacted alkali metal hydroxide and alkali metal carboxylate to alkali as a polymerization aid. Manufacture of polyphenylene sulfide in which energy consumption is greatly reduced because the content of residual alkali metal carboxylate in the waste washing solution is extremely low and no distillation process is required to remove the metal carboxylate by equilibrium movement of the metal carboxylate to carboxylic acid It has the effect of providing a method.

Description

Method for producing polyphenylene sulfide {METHOD FOR FOR PREPARING OF POLYPHENYLENE SULFIDE}

The present invention relates to a method for preparing polyphenylene sulfide, and more particularly, a distillation process for removing the alkali metal carboxylate content by significantly reducing the content of alkali metal carboxylate remaining in the waste washing solution by adding acid before the washing step after polymerization A method for producing polyphenylene sulfide in which cost is reduced because this is not necessary, and raw material costs are reduced by recovering the carboxylic acid equilibrium shifted by the acid in the drying step, neutralizing it with an alkali metal carboxylate and reusing it in the polymerization process is about

In recent years, the demand for thermoplastic resins with high heat resistance and good chemical resistance as materials for parts of electrical and electronic devices and chemical devices is increasing. One of these thermoplastic resins, polyphenylene sulfide (PPS), has been in the spotlight as a filter material because of its excellent strength, processability, chemical resistance and heat resistance.

Polyphenylene sulfide is the condensation polymerization of dichlorobenzene (p-DCB) and sodium sulfide (Na ₂ S) and grows to a high molecular weight only in the solvent of N-methyl-2-pyrrolidone (N-Methyl-2-pyrrolidone). has a characteristic that

As high molecular weight polyphenylene sulfide, there are linear polyphenylene sulfide and cross-linked polyphenylene sulfide. Linear polyphenylene sulfide is polymerized using sodium acetate (NaAc) as a polymerization aid. After polymerization, polyphenylene sulfide is And sodium chloride as a by-product and sodium acetate as a polymerization aid are precipitated in the form of salts, which are removed by evaporating N-methyl-2-pyrrolidone and washing with water. At this time, the amount of water required for washing is several dozen times that of polyphenylene sulfide, which results in a large amount of wastewater.

Sodium acetate is a substance with a very high COD (Chemical Oxygen Demand), and the washing water containing it cannot be discharged directly as waste water, so it is difficult to treat. Also, acid is added to the washing water containing sodium acetate to convert sodium acetate into acetic acid, which is a distillation process In the case of purification with acetic acid, since the boiling point of acetic acid is higher than water at 118° C., a large amount of water needs to be evaporated, so there is a problem in that energy consumption is very large.

Therefore, there is a need to develop a manufacturing method for reducing the amount of energy used to purify polyphenylene sulfide by effectively removing the alkali metal carboxylate used as a polymerization aid after the polymerization is completed.

Japanese Patent Laid-Open No. 1999-171997

In order to solve the problems of the prior art as described above, the present substrate is prepared by adding an acid to an alkali metal carboxylate used as a polymerization aid after polymerization of polyphenylene sulfide and before the washing step of unreacted alkali metal hydroxide and alkali metal carboxylate. A method for preparing polyphenylene sulfide that does not require a distillation process to remove the content of alkali metal carboxylate significantly reduced in the washing step by adding more than the equivalent sum to equilibrium shift to carboxylic acid and then evaporating with an organic solvent aims to provide

The above and other objects of the present disclosure can all be achieved by the present disclosure described below.

In order to achieve the above object, the present

(a) heating a mixture comprising a sulfur source, an alkali metal hydroxide, an alkali metal carboxylate, an organic solvent and water to evaporate the water to obtain a residual mixture;

(b) adding a dihalogenated aromatic compound and an organic solvent to the remaining mixture and performing a polymerization reaction to obtain a polymerization product;

(c) adding an acid to the polymerization product in an amount equal to or greater than the equivalent of unreacted alkali metal hydroxide and alkali metal carboxylate, thereby shifting the alkali metal carboxylate into equilibrium with carboxylic acid;

(d) removing the organic solvent, the unreacted residual dihalogenated aromatic compound and the carboxylic acid by drying the polymerized product equilibrium shifted to the carboxylic acid;

(e) washing the polymerization product from which the organic solvent, unreacted residual dihalogenated aromatic compound and carboxylic acid are removed with a washing solution and dehydrating; and

(f) drying the dehydrated polymerization product; including,

The washing solution provides a method for producing polyphenylene sulfide, characterized in that water, acetone or ethanol.

According to the present description, after polymerizing polyphenylene sulfide, acid is added before the washing step to significantly reduce the content of alkali metal carboxylate remaining in the waste washing solution, so that a distillation process is not required to remove it, resulting in a large energy consumption. There is an effect of providing a method for producing polyphenylene sulfide in which raw material costs are reduced by reducing and reusing the carboxylic acid, which has been moved to equilibrium by the acid, in the drying step, neutralized with an alkali metal carboxylate and reused.

1 is a diagram schematically illustrating steps of polymerization, drying and washing of polyphenylene sulfide according to the present disclosure.

Hereinafter, a method for producing the polyphenylene sulfide of the present disclosure will be described in detail.

The present inventors have worked tirelessly to solve the problem that a lot of energy is consumed to remove the residual alkali metal carboxylate after the polymerization of polyphenylene sulfide is completed. When the alkali metal carboxylate is equilibrated to carboxylic acid and then removed by evaporation with an organic solvent, there is almost no alkali metal carboxylate in the washing solution used for subsequent washing. It was confirmed that the distillation process is not required, and based on this, more efforts were made to research to complete the present invention.

The method for producing polyphenylene sulfide according to the present invention is

(a) heating a mixture comprising a sulfur source, an alkali metal hydroxide, an alkali metal carboxylate, an organic solvent and water to evaporate the water to obtain a residual mixture;

(b) adding a dihalogenated aromatic compound and an organic solvent to the remaining mixture and performing a polymerization reaction to obtain a polymerization product;

(c) adding an acid to the polymerization product in an amount equal to or greater than the equivalent of unreacted alkali metal hydroxide and alkali metal carboxylate, thereby shifting the alkali metal carboxylate into equilibrium with carboxylic acid;

(d) drying the polymerized product equilibrium shifted to the carboxylic acid to remove an organic solvent, unreacted residual dihalogenated aromatic compound and carboxylic acid;

(e) washing the polymerization product from which the organic solvent, unreacted residual dihalogenated aromatic compound and carboxylic acid are removed with a washing solution and dehydrating; and

(f) drying the dehydrated polymerization product; including, wherein the washing solution is water, acetone or ethanol, and in this case, since the alkali metal carboxylate remaining in the washing solution is very trace amount, to remove it Since the distillation process is not required, energy consumption is greatly reduced.

The manufacturing method of the polyphenylene sulfide may be, for example, a distillation wastewater treatment process free, and in this case, it is environmentally friendly and does not require a distillation process, thereby significantly reducing energy consumption.

In the present description, "distillation wastewater treatment process free" means that a distillation process is not required. Specifically, the content of alkali metal carboxylate as a polymerization aid in the washing water dehydrated after washing the polymerized polyphenylene sulfide is very low, so it is removed. It refers to that which does not require a distillation process to do so.

In step (a), a mixture containing a sulfur source, an alkali metal hydroxide, an alkali metal carboxylate, an organic solvent, and water is heated to evaporate water to obtain a residual mixture.

The sulfur source is not particularly limited as long as it is a solid sulfur source. For example, it may be formed by reacting alkali metal sulfide and alkali metal hydroxide, and specific examples thereof include sodium hydrogen sulfate, sodium hydrogen sulfide, sodium sulfide, potassium sulfide, and the like. .

The sulfur source reacts with, for example, an alkali metal hydroxide to form an alkali metal sulfide, and then polymerizes with a dihalogenated aromatic compound to form polyphenylene sulfide.

The alkali metal hydroxide may be, for example, at least one selected from the group consisting of sodium hydroxide, potassium hydroxide, lithium hydroxide and cesium hydroxide, preferably sodium hydroxide, and in this case, there is an excellent effect of reactivity and physical property balance

The alkali metal carboxylate is used as a polymerization aid to accelerate the polymerization reaction, thereby increasing the degree of polymerization of polyphenylene sulfide in a short time. For example, lithium acetate, sodium acetate, potassium acetate, magnesium acetate, sodium hexanoate, It may be at least one selected from the group consisting of lithium hexanoate and lithium benzoate, preferably sodium acetate, in which case there is an excellent effect in reactivity and balance of physical properties.

The alkali metal hydroxide may be used, for example, in the range of 0.5 to 2.0 equivalents, or 1.0 to 1.5 equivalents of the alkali metal hydroxide based on 1 equivalent of the sulfur source, and within this range, the physical properties of polyphenylene sulfide are excellent.

The alkali metal carboxylate may be used in the range of 0.01 to 1.5 or 0.05 to 1.0 equivalent of the alkali metal carboxylate based on 1 equivalent of the sulfur source, for example, and within this range, the excellent effect of the physical properties of polyphenylene sulfide is have.

As a specific example, sodium hydroxide (NaOH) may be used in the range of 0.99 to 1.20 equivalents, 1.04 to 1.16 equivalents, or 1.08 to 1.12 equivalents, and sodium acetate is 0.10 to 1.12 equivalents based on sodium hydrogen sulfide (NaSH) 70% concentration, 1.05 equivalents 0.70 equivalents, 0.20 to 0.60 equivalents, or 0.30 to 0.50 equivalents.

The organic solvent may be a polar solvent for dissolving each raw material, for example, may be at least one selected from alcohol, alkylene oxide, and N-methylpyrrolidone.

The organic solvent may be used, for example, in the range of 1.0 to 5.0 equivalents, or 2.0 to 4.0 equivalents of the organic solvent, and 1.0 to 15.0 equivalents, or 4.0 to 10.0 equivalents of water, based on 1 equivalent of the sulfur source.

As a specific example, based on sodium hydrogen sulfide (NaSH) 70% concentration, 1.05 equivalents, the organic solvent may be used in the range of 1 to 4 equivalents, 2 to 4 equivalents, or 3 to 4 equivalents, and 4 to 10 equivalents of water, 4 to 9 equivalents, or in the range of 4 to 8 equivalents.

In order to evaporate water in the mixture, for example, while stirring the mixture, the mixture may be heated and stirred at a temperature of 170 to 230 ° C. for 1 to 3 hours, or at a temperature of 190 to 210 ° C. for 1 to 2 hours, within this range. A part of the organic solvent and water are effectively removed from the process, so that the polymerization reaction proceeds smoothly.

The residual mixture may, for example, be produced by a reaction of water, a sulfur source, and an alkali metal hydroxide, and may be _{Na 2 S as a specific example.}

In the next step (b), a dihalogenated aromatic compound and an organic solvent are added to the residual mixture and polymerized to obtain a polymerization product.

Various types of the dihalogenated aromatic compound may be selected, for example, p-dichlorobenzene, m-dichlorobenzene, o-dichlorobenzene, 1,3,5-trichlorobenzene, 1,2,4-trichlorobenzene , 1,2,4,5-tetrachlorobenzene, hexachlorobenzene, 2,5-dichlorotoluene, 2,5-dichloro-p-xylene, 1,4-dibromobenzene, 1,4-diiodobenzene It may be at least one selected from polyhalogenated aromatic compounds consisting of , and 1-methoxy-2,5-dichlorobenzene, among which para- which can introduce a halogen end group, specifically a chlorine end group, to polyphenylene sulfide. Dihalogen benzene is preferred. If necessary, a dihalogenated aromatic compound can be used individually or in mixture of 2 or more types.

The dihalogenated aromatic compound (DH) may have an equivalent ratio (S/DH) with the sulfur source (S) used in step (a) described above, for example, 0.50 to 1.50, or 0.90 to 1.20, within this range. There is an excellent effect of the physical property balance.

The organic solvent may be used, for example, in an amount of 0.5 to 5 equivalents, or 1 to 4 equivalents based on 1 equivalent of the dihalogenated aromatic compound.

For the polymerization, for example, 200 to 280 ℃, 220 to 260 ℃, or may be stirred by raising the temperature to 240 to 260 ℃, if necessary, the temperature is raised to a temperature of 200 to 240 ℃ to react, then 240 to 280 It can be stirred in multiple stages by raising the temperature to a temperature of ℃.

For example, the polymerization may be carried out for 3 to 10 hours, or 4 to 7 hours.

After the polymerization, for example, the pressure may be adjusted to atmospheric pressure, or 0.5 to 1.5 atmospheres.

In the next step (c), an acid is added to the polymerization product in an amount equal to or greater than the equivalent of the unreacted alkali metal hydroxide and the alkali metal carboxylate to move the alkali metal carboxylate to equilibrium with the carboxylic acid.

The acid may be added, for example, in an amount greater than or equal to the equivalent of the unreacted alkali metal hydroxide and the alkali metal carboxylate, and within this range, the alkali metal carboxylate is equilibrated to the carboxylic acid, and the alkali metal carboxylate is added to the dehydrated washing solution. Since there is no acid residue, the distillation process can be omitted, and thus energy consumption is greatly reduced.

The acid is added in an amount equal to or greater than the equivalent of the unreacted alkali metal hydroxide and the alkali metal carboxylate, and the pH of the polymerization product is, for example, 1 to 7, or 3 to 6, and within this range, the alkali metal carboxylate is carboxylate. There is an effect that the distillation process is omitted because the alkali metal carboxylate does not remain in the washing solution due to the equilibrium shift to the acid.

The acid may be, for example, at least one selected from the group consisting of hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, nitric acid, acetic acid, formic acid, acetic acid and propionic acid, and preferably hydrochloric acid, in this case alkali metal carboxylate There is an effect that the equilibrium shift to the carboxylic acid is easily achieved.

As a specific example, when sodium acetate is used as a polymerization aid and hydrochloric acid is used as an acid, sodium acetate may be equilibrium shifted to acetic acid by hydrochloric acid.

In the next step (d), the organic solvent, the unreacted dihalogenated aromatic compound and the carboxylic acid are removed by drying the polymerization product that has been equilibrated to the carboxylic acid.

The drying may be carried out, for example, at 120 to 170° C. and 0.05 to 0.5 bar for 100 to 150 minutes, or at 130 to 160° C. and 0.05 to 0.3 bar for 110 to 130 minutes, and within this range, an organic solvent, The reactive dihalogenated aromatic compound and carboxylic acid are easily removed, and the raw material cost is reduced by neutralizing and reusing the removed carboxylic acid.

In step (d), the drying may be carried out, for example, in a fractional distiller, and in this case, the carboxylic acid, the organic solvent, and the unreacted dihalogenated aromatic compound may be easily separated according to boiling points.

The removed carboxylic acid may be, for example, neutralized with a basic compound, recovered as an alkali metal carboxylate, and then reused for polymerization, in which case raw material cost is reduced.

The basic compound may be, for example, at least one selected from the group consisting of sodium hydroxide, sodium hydrogen carbonate and sodium carbonate, preferably sodium hydroxide.

As a specific example, when sodium acetate is used as a polymerization aid and hydrochloric acid is used as an acid, sodium acetate is equilibrium shifted to acetic acid by hydrochloric acid, and the evaporated acetic acid is neutralized by sodium hydroxide as a basic compound to become sodium acetate, which Since it can be recovered and reused for polymerization, there is an effect of reducing the cost of raw materials.

In the next step (e), the polymerization product from which the organic solvent, unreacted residual dihalogenated aromatic compound and carboxylic acid are removed is washed with a washing solution and dehydrated.

The washing solution may be, for example, water, acetone or ethanol, and in this case, it is possible to effectively remove carboxylic acids and oligomers.

The step (e) includes, for example, (e-1) washing and dehydrating the polymerization product with a washing solution, and (e-2) washing and dehydrating the polymerization product that has undergone the step (e-1) again with a washing solution. In this case, carboxylic acids and oligomers can be effectively removed.

In the step (e-1), for example, after washing for 50 to 80 minutes, 55 to 75 minutes, or 60 to 70 minutes with a washing solution of 15 to 30 ° C., or 20 to 25 ° C., the principle can be separated and dehydrated, In the step (e-2), for example, when water is used as a washing liquid, the principle is separated after washing at 75 to 98 ° C., or 80 to 95 ° C. for 50 to 80 minutes, 55 to 75 minutes, or 60 to 70 minutes. In the case of using acetone or ethanol as a washing solution, it can be dehydrated by separating in principle after washing for 50 to 80 minutes, 55 to 75 minutes, or 60 to 70 minutes at 15 to 30 ° C, or 20 to 25 ° C. , in this case, the effect of removing carboxylic acids and oligomers is excellent.

In step (e-1), the washing solution may be preferably water, and in this case, the carboxylic acid and oligomer removal effect is excellent.

Steps (e-1) and (e-2) may be performed, for example, one or more times, 1 to 5 times, 1 to 3 times, or once, respectively, in this case, the carboxylic acid and the oligomer are removed The effect of becoming is excellent.

The content of the alkali metal carboxylate in the washing solution dehydrated in step (e), specifically, the total amount of water dehydrated after washing in steps (e-1) and (e-2) is 100 ppm or less, or 10 to 40 ppm, and within this range, the distillation process can be omitted, thereby reducing energy consumption.

In the next step (f), the dehydrated polymerization product is dried.

The dehydrated polymerization product may be vacuum dried at 100 to 150° C. for 1 to 3 hours to remove moisture.

As described above, according to the method for producing polyphenylene sulfide according to the present description, an acid is added after the polymerization is completed and before the washing step, the alkali metal carboxylate, which is a polymerization aid, is removed by equilibrium shifting to carboxylic acid, thereby dehydration By reducing the content of the alkali metal carboxylate remaining in the washed washing solution, a distillation process is not required to remove it, so it is possible to implement a method for producing polyphenylene sulfide in which energy consumption is reduced.

Hereinafter, preferred examples are presented to help the understanding of the present disclosure, but the following examples are merely illustrative of the present disclosure, and it will be apparent to those skilled in the art that various changes and modifications are possible within the scope and technical spirit of the present disclosure, It goes without saying that such variations and modifications fall within the scope of the appended claims.

[Example]

Example One

As step (a), 105 g of water, 60 g of NaSH, 45 g of NaOH, 174 g of NMP, and 38 g of sodium acetate (NaAc) were mixed and then heated to 200° C. for dehydration to obtain a residual mixture.

As step (b), 142 g of NMP and 156 g of p-DCB were mixed with the remaining mixture and polymerization was performed at 250° C. for 300 minutes under stirring to obtain a polymerization product, and then the pressure was adjusted to 1 atm.

As step (c), 200 g of a 10 wt% aqueous solution of HCl was added to the polymerization reactant to equilibrate sodium acetate to acetic acid. At this time, the pH was 6.

As step (d), the polymerization reaction product equilibrated with acetic acid was dried at 150° C. and 0.1 bar reduced pressure for 120 minutes to remove NMP, acetic acid and p-DCB.

As step (e-1), the polymerized product from which NMP, acetic acid and p-DCB were removed was washed with 1000 g of water at 20 to 25° C. for 60 minutes, and then dehydrated by centrifugation. Thereafter, 1000 g of water at 90° C. was added to the polymerization reaction product that had undergone step (e-1) in step (e-2) for 60 minutes, and then dehydrated through centrifugation to remove carboxylic acids and oligomers. did.

At this time, the content of sodium acetate and sodium chloride remaining in the total of dehydrated water after washing in steps (e-1) and (e-2) was measured.

As step (f), the remaining moisture of the cake was vacuum-dried at 150° C. for 60 minutes.

Example 2

In the step (c) of Example 1, 300 g of a 10 wt% aqueous solution of HCl was added, and at this time, the pH was 5, except that it was carried out in the same manner as in Example 1.

Example 3

After washing with 500 g of water at 20 to 25 ° C. for 60 minutes in step (e-1) of Example 1, the process of dehydration was repeated three times in total, and then the washing in step (e-2) was performed at 20 to 25 ° C. It was carried out in the same manner as in Example 1, except that 500 g of acetone was used for 60 minutes.

At this time, the content of sodium acetate and sodium chloride remaining in the total water dehydrated after washing in step (e-1) was measured.

Example 4

In the step (c) of Example 1, 350 g of a 10 wt% aqueous solution of sulfuric acid was added, and the same procedure as in Example 1 was performed, except that the pH was 5.

comparative example One

It was carried out in the same manner as in Example 1, except that in step (c) of Example 1, the pH was maintained at 13 without adding a 10 wt% aqueous solution of HCl.

comparative example 2

Example 1 (c) was carried out in the same manner as in Example 1, except that 100 g of a 10 wt% aqueous solution of HCl was added to adjust the pH to 8.

Composition (g) Example 1 Example 2 Example 3 Example 4 Comparative Example 1 Comparative Example 2 water 1950 1955 1445 1960 1940 1950 sodium acetate 0 0 0 0 38 25 sodium chloride 138 140 137 111 108 124

As shown in Table 1, in Examples 1 to 4 according to the present description, sodium acetate remaining in the total of the water dehydrated in steps (e-1) and (e-2) was not detected, so the washing solution was not distilled. It was confirmed that the distillation process was not required because the wastewater could be directly discharged.

On the other hand, Comparative Example 1 in which hydrochloric acid was not added and Comparative Example 2 in which hydrochloric acid was added at an equivalent ratio of unreacted alkali metal hydroxide and alkali metal carboxylate was less than in steps (e-1) and (e-2) in steps (e-1) and (e-2) Since the content of sodium acetate remaining in the dehydrated water is excessive and it has to undergo a distillation process to remove it, energy consumption is very high.

Claims (13)

(a) heating a mixture comprising a sulfur source, an alkali metal hydroxide, an alkali metal carboxylate, an organic solvent and water to evaporate the water to obtain a residual mixture;
(b) adding a dihalogenated aromatic compound and an organic solvent to the remaining mixture and performing a polymerization reaction to obtain a polymerization product;
(c) adding an acid to the polymerization product in an amount equal to or greater than the equivalent of an unreacted alkali metal hydroxide and an alkali metal carboxylate to balance the alkali metal carboxylate to carboxylic acid;
(d) removing the organic solvent, the unreacted residual dihalogenated aromatic compound and the carboxylic acid by drying the polymerized product equilibrium shifted to the carboxylic acid;
(e) washing the polymerization product from which the organic solvent, unreacted residual dihalogenated aromatic compound and carboxylic acid are removed with a washing solution and dehydrating; and
(f) drying the dehydrated polymerization product; including,
The washing solution is water, acetone or ethanol,
The acid of step (c) is added in an amount such that the pH of the polymerization product is 3 to 6,
The method for producing polyphenylene sulfide, characterized in that the washing solution dehydrated in step (e) has an alkali metal carboxylate content of 100 ppm or less.
delete delete According to claim 1,
A method for producing polyphenylene sulfide, characterized in that the carboxylic acid removed in step (d) is neutralized with a basic compound, recovered as an alkali metal carboxylate, and then reused for polymerization.
According to claim 1,
Method for producing polyphenylene sulfide, characterized in that heating the mixture at a temperature of 170 to 230 ℃ for 1 to 3 hours while stirring in order to evaporate the water in step (a).
According to claim 1,
The polymerization of step (b) is a method for producing polyphenylene sulfide, characterized in that it is carried out under conditions of 200 to 280 ℃.
According to claim 1,
The method for producing polyphenylene sulfide, characterized in that the drying in step (d) is carried out at 120 to 170 ℃ and 0.05 to 0.5 bar for 100 to 150 minutes.
According to claim 1,
The method for producing polyphenylene sulfide, characterized in that the drying in step (d) is carried out in a fractional distiller.
According to claim 1,
The step (e) includes (e-1) washing and dehydrating the polymerized product with a washing solution and (e-2) washing and dehydrating the polymerized product that has undergone step (e-1) with a washing solution again Method for producing polyphenylene sulfide, characterized in that.
10. The method of claim 9,
The washing in step (e-1) is carried out for 50 to 80 minutes with a washing solution at 15 to 30 °C, and washing in step (e-2) is water at 75 to 98 °C, acetone at 15 to 30 °C, or 15 A method for producing polyphenylene sulfide, characterized in that it is carried out for 50 to 80 minutes with ethanol at 30°C.
According to claim 1,
The sulfur source is a method for producing polyphenylene sulfide, characterized in that at least one selected from the group consisting of sodium hydrogen sulfate, sodium sulfide and potassium sulfide.
According to claim 1,
The alkali metal carboxylate is at least one selected from the group consisting of lithium acetate, sodium acetate, potassium acetate, magnesium acetate, sodium hexanoate, lithium hexanoate and lithium benzoate Preparation of polyphenylene sulfide Way.
According to claim 1,
The acid is hydrochloric acid, sulfuric acid, sulfurous acid, phosphoric acid, nitric acid, acetic acid, formic acid, acetic acid and a method for producing polyphenylene sulfide, characterized in that at least one selected from the group consisting of propionic acid.

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