JP6221326B2 - Method for producing cyclic polyarylene sulfide - Google Patents

Description

  The present invention relates to a method for economically producing cyclic polyarylene sulfide.

  Aromatic cyclic compounds can be applied to highly functional materials and functional materials based on properties resulting from their cyclic properties, such as properties as compounds with inclusion ability, and synthesis of high molecular weight linear polymers. In recent years, it has attracted attention due to its specificity derived from its structure, such as its use as an effective monomer for the purpose. Cyclic polyarylene sulfide (hereinafter, polyarylene sulfide may be abbreviated as PAS) also belongs to the category of aromatic cyclic compounds and is a notable compound as described above.

  As a method for producing a cyclic polyarylene sulfide, for example, a method in which a diaryl disulfide compound is oxidatively polymerized under ultradilution conditions has been proposed (see, for example, Patent Document 1). In this method, it is presumed that cyclic polyarylene sulfide is produced with high selectivity, and that only a small amount of linear polyarylene sulfide is produced, and it is considered that cyclic polyarylene sulfide is obtained in high yield. However, this method has many problems from the viewpoint of industrial applicability. First, it is essential to carry out the reaction under ultra-dilution conditions, and there is very little cyclic polyarylene sulfide obtained per unit volume of the reaction solution, and it is difficult to efficiently obtain cyclic polyarylene sulfide. Moreover, since the reaction temperature of the method is around room temperature, the reaction requires a long time of several tens of hours, resulting in poor productivity. Further, the linear polyarylene sulfide produced as a by-product in this method is a target product. Since the molecular weight is close to that of the cyclic polyarylene sulfide, it is difficult to separate and remove, and high-purity cyclic polyarylene sulfide cannot be obtained efficiently. For this purpose, for example, an expensive oxidizing agent such as dichlorodicyanobenzoquinone is required to be equivalent in amount to the raw material diaryl disulfide, and the cyclic polyarylene is inexpensive. That can not be obtained Fido, there is a problem, such as.

  As another method for producing a cyclic polyarylene sulfide, a method in which a copper salt of 4-bromothiophenol is heated under ultradilution conditions in quinoline (see, for example, Patent Document 2) is also disclosed. As in Patent Document 1, ultra-dilution conditions are essential, and a long time is required for the reaction, which is a very low productivity method. Furthermore, it is difficult to separate the by-produced copper bromide from the product cyclic polyarylene sulfide, and the resulting cyclic polyarylene sulfide has a low purity.

  As a method for obtaining cyclic polyarylene sulfide from general-purpose raw materials such as a sulfidizing agent and a dihalogenated aromatic compound by desalting condensation, the amount of sodium sulfide relative to N-methylpyrrolidone is 0.1 mol / liter, and dichlorobenzene is added thereto. Has been disclosed (see, for example, Non-Patent Document 1). In this method, it can be assumed that the amount of the organic polar solvent relative to 1 mol of sulfur component of the sulfiding agent is 1.25 liters or more, so that it is possible to obtain cyclic polyarylene sulfide. However, a very small amount of cyclic polyarylene sulfide is obtained. However, the obtained cyclic polyarylene sulfide has a low purity, and there is a problem that a long time is required for the reaction.

  As a method for solving the above problems of the production method, a sulfidizing agent and a dihalogenated aromatic compound are used in an organic polar solvent of 1.25 liters or more per 1 mol of the sulfur component of the sulfidizing agent, and the reaction mixture is usually used. A method of heating beyond the reflux temperature in the pressure is disclosed (for example, see Patent Document 3). In this method, it was confirmed that the consumption rate of the dihalogenated aromatic compound reached about 90% in a relatively short time of 0.5 to 2 hours, and the selectivity of the cyclic polyarylene sulfide was improved to about 35%. Yes.

  However, in the method for producing cyclic polyarylene sulfide shown in Patent Document 3, the reaction mixture is heated at a high temperature exceeding the reflux temperature at normal pressure because the water content of the reaction mixture is high, and the pressure of the reaction system is high. There is a problem that it is economically disadvantageous because it requires expensive pressure-resistant equipment.

  As a method for solving the above-mentioned problem relating to the high pressure of the reaction system derived from the moisture content of this reaction mixture, a sulfidizing agent having a water content of 0.8 mol or more per mol of sulfur component is dehydrated in an organic polar solvent to remove sulfur. A method for producing a cyclic polyarylene sulfide comprising a step of forming a mixture having a low water content of a sulfidizing agent of less than 0.8 mol per mol of the component is disclosed (for example, Patent Document 4). In this method, a dehydration step is introduced before carrying out the reaction of the cyclic polyarylene sulfide, and this reduces the contribution of pressure increase due to residual moisture in the system, thereby reducing the pressure of the entire reaction system. It was possible.

Japanese Patent No. 3200027 (Claims) US Pat. No. 5,869,599 (page 14) JP 2009-030012 (pages 28-33) JP, 2011-149014, A (Claims)

Polymer (Polymer), vol.37, No.14, p.3111-3112, 1996

  However, in the invention of Patent Document 4, since the resulting sulfidizing agent mixture has a solidification temperature of about 140 ° C., when the sulfidizing agent mixture is used separately or transferred, it is used at a high temperature of 140 ° C. or higher. It has been desired to be able to transport at a lower temperature. In addition, solid content is generated and settled in the reactor depending on the conditions during dehydration, and when this is divided and transferred, it is somewhat difficult to adjust the molar balance of the reaction mixture. In view of the above, an object of the present invention is to solve the above-described problems of the prior art and to provide a method for economically and efficiently producing cyclic polyarylene sulfide.

In order to solve the above problems, the present invention provides a method for producing a cyclic polyarylene sulfide having the following characteristics.
[1] A method for producing a cyclic polyarylene sulfide by heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound and an organic polar solvent, comprising at least the following steps (i) and (ii): A process for producing a cyclic polyarylene sulfide, comprising:
(I) at least sulfidizing agent, a mixture comprising an organic polar solvent and water, a mixture comprising an organic polar solvent under 0.4 liters sulfur contained 1 mole per 0.1 liters or more of the sulfidizing agent 0.99 ° C. or higher Heating at 250 ° C. or lower, and preparing a sulfidizing agent mixture having a water content of 0.8 mol or more and 6.0 mol or less per mol of sulfur component of the sulfidizing agent, at least after step (i) The reaction mixture containing the sulfidizing agent mixture obtained in step (i), the dihalogenated aromatic compound and the organic polar solvent is 1.25 liters to 50 liters per mole of the sulfur component in the reaction mixture. [2] The cyclic polysulfide according to [1], wherein the mixture of sulfidizing agents obtained in step (i) is uniform. Manufacturing method of arylene sulfide.
[3] In step (i), a mixture containing an organic polar solvent of 0.1 liter or more and less than 0.4 liter per mole of the sulfur component of the sulfidizing agent is heated, and the water content is 1 mol of the sulfur component of the sulfidizing agent. The method for producing a cyclic polyarylene sulfide according to [1] or [2], wherein a mixture of 0.8 mol to 3.0 mol of a sulfidizing agent mixture is prepared.
[4] In step (i), a mixture containing more than 3.0 moles of water per mole of sulfur component of the sulfidizing agent is heated to dehydrate, and the amount of water is reduced to 0.8 per mole of sulfur component of the sulfidizing agent. The method for producing a cyclic polyarylene sulfide according to [3], wherein a mixture of the sulfidizing agent reduced to a molar amount of 3.0 to 3.0 mol is obtained.
[5] The method for producing a cyclic polyarylene sulfide according to any one of [1] to [4], wherein the steps (i) and (ii) are carried out in separate reactors.
[6] In the reactor in which step (i) is carried out after step (i), the organic polar solvent is added to the sulfidizing agent mixture and diluted so that the organic polar solvent is 0.4 liter or more per mole of sulfur component. The method for producing a cyclic polyarylene sulfide according to any one of [1] to [5], wherein:
[7] The method for producing a cyclic polyarylene sulfide according to any one of [1] to [6], wherein the reaction mixture is heated in step (ii) above the reflux temperature at normal pressure.
[8] The method for producing a cyclic polyarylene sulfide as described in any one of [1] to [7], wherein the pressure in step (ii) is 0.8 MPa or less in terms of gauge pressure.
[9] The method for producing a cyclic polyarylene sulfide as described in any one of [1] to [8], wherein the sulfidizing agent is an alkali metal sulfide.
[10] The method for producing a cyclic polyarylene sulfide as described in any one of [1] to [9], wherein the dihalogenated aromatic compound is dichlorobenzene.
[11] The method for producing a cyclic polyarylene sulfide as described in any one of [1] to [10], wherein linear polyarylene sulfide is contained in the reaction mixture before performing step (ii).

  ADVANTAGE OF THE INVENTION According to this invention, the method of manufacturing a cyclic polyarylene sulfide stably with a favorable yield can be provided. More specifically, in the production of cyclic polyarylene sulfide that introduces a homogenization step by heating the raw material, by utilizing the high transportability of the uniform sulfidizing agent mixture obtained in this step, the molar balance of the raw material in the reaction mixture Can be precisely adjusted, and a method for producing a cyclic polyarylene sulfide with a good yield can be provided by sufficiently consuming raw materials without using expensive pressure-resistant equipment.

  Embodiments of the present invention will be described below.

(1) Sulfiding agent The sulfiding agent used in the present invention may be any sulfidizing agent as long as it can introduce a sulfide bond into a dihalogenated aromatic compound. For example, alkali metal sulfide, alkali metal hydrosulfide, and hydrogen sulfide may be used. Can be mentioned.

  Specific examples of the alkali metal sulfide include lithium sulfide, sodium sulfide, potassium sulfide, rubidium sulfide, cesium sulfide and a mixture of two or more thereof, among which lithium sulfide and / or sodium sulfide are preferable. Sodium sulfide is more preferably used. These alkali metal sulfides can be used as hydrates or aqueous mixtures or in the form of anhydrides. The aqueous mixture refers to an aqueous solution, a mixture of an aqueous solution and a solid component, or a mixture of water and a solid component. Since generally available inexpensive alkali metal sulfides are hydrates or aqueous mixtures, it is preferred to use such forms of alkali metal sulfides.

  Specific examples of the alkali metal hydrosulfide include, for example, lithium hydrosulfide, sodium hydrosulfide, potassium hydrosulfide, lithium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures of two or more thereof. Lithium hydrosulfide and / or sodium hydrosulfide are preferable, and sodium hydrosulfide is more preferably used.

  In addition, an alkali metal sulfide prepared in situ in a reaction system from an alkali metal hydrosulfide and an alkali metal hydroxide can also be used. Alternatively, an alkali metal sulfide prepared by previously contacting an alkali metal hydrosulfide and an alkali metal hydroxide can be used. These alkali metal hydrosulfides and alkali metal hydroxides can be used as hydrates or aqueous mixtures, or in the form of anhydrides. From the viewpoint of availability and cost of hydrates or aqueous mixtures. preferable.

  Furthermore, alkali metal sulfides prepared in situ in the reaction system from alkali metal hydroxides such as lithium hydroxide and sodium hydroxide and hydrogen sulfide can also be used. Further, alkali metal sulfides prepared by previously contacting alkali metal hydroxides such as lithium hydroxide and sodium hydroxide with hydrogen sulfide can also be used. Hydrogen sulfide can be used in any form of gas, liquid, and aqueous solution.

  In the present invention, the amount of the sulfidizing agent is subtracted from the actual charge when the loss of the sulfidizing agent partially occurs before the start of the reaction with the dihalogenated aromatic compound due to dehydration operation or the like. It shall mean the remaining amount.

  An alkali metal hydroxide and / or an alkaline earth metal hydroxide can be used in combination with the sulfidizing agent. Specific examples of the alkali metal hydroxide include sodium hydroxide, potassium hydroxide, lithium hydroxide, rubidium hydroxide, cesium hydroxide, and a mixture of two or more thereof. Specific examples of the metal hydroxide include magnesium hydroxide, calcium hydroxide, strontium hydroxide, barium hydroxide, and the like. Among them, sodium hydroxide is preferably used.

  When an alkali metal hydrosulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time, but the amount used is lower than 0.80 mol per mol of the alkali metal hydrosulfide. And preferably 0.95 mol or more, more preferably 1.005 mol or more. Moreover, the upper limit can illustrate 1.50 mol or less, Preferably it is 1.25 mol, More preferably, the range of 1.20 mol can be illustrated. When hydrogen sulfide is used as the sulfiding agent, it is particularly preferable to use an alkali metal hydroxide at the same time. In this case, the lower limit is 1.60 mol or more with respect to 1 mol of hydrogen sulfide. Is preferably 1.90 mol or more, more preferably 2.01 mol or more. Moreover, the upper limit can illustrate 3.00 mol or less, Preferably it is 2.50 mol or less, More preferably, it is 2.40 mol or less. Here, the cyclic PAS can be obtained in a high yield by setting the amount of the alkali metal hydroxide used within the above range, but the cyclic PAS produced is easily decomposed even if the amount is more than or less than the above range. The yield tends to decrease.

(2) Dihalogenated aromatic compound As the dihalogenated aromatic compound used in the production of the cyclic PAS of the present invention, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, p-dibromobenzene, o- Dihalogenated benzene such as dibromobenzene, m-dibromobenzene, 1-bromo-4-chlorobenzene, 1-bromo-3-chlorobenzene, and 1-methoxy-2,5-dichlorobenzene, 1-methyl-2,5-di Dihalogenated aromatic compounds containing substituents other than halogen such as chlorobenzene, 1,4-dimethyl-2,5-dichlorobenzene, 1,3-dimethyl-2,5-dichlorobenzene and 3,5-dichlorobenzoic acid And so on. Especially, the dihalogenated aromatic compound which has p-dihalogenated benzene represented by p-dichlorobenzene as a main component is preferable. Particularly preferably, it contains 80 to 100 mol%, more preferably 90 to 100 mol% of p-dichlorobenzene. It is also possible to use two or more different dihalogenated aromatic compounds in combination in order to produce a cyclic PAS copolymer.

(3) Organic Polar Solvent In the production of the cyclic PAS of the present invention, an organic polar solvent is used as a reaction solvent. Among them, an organic amide solvent is preferably used. Specific examples include N-alkylpyrrolidones such as N-methyl-2-pyrrolidone, N-ethyl-2-pyrrolidone and N-cyclohexyl-2-pyrrolidone, caprolactams such as N-methyl-ε-caprolactam, An aprotic organic solvent typified by 3-dimethyl-2-imidazolidinone, N, N-dimethylacetamide, N, N-dimethylformamide, hexamethylphosphoric triamide, etc., and a mixture thereof, have a stable reaction. It is preferably used because it is expensive. Of these, N-methyl-2-pyrrolidone and 1,3-dimethyl-2-imidazolidinone are preferably used.

(4) Sulfidation agent mixture The sulfidation agent mixture in the production of the cyclic PAS of the present invention is a mixture containing the above sulfidation agent and an organic polar solvent. This sulfidizing agent mixture exhibits various properties such as solid, liquid, and jelly depending on the temperature and water content, but it is heated under the preferred mode of the present invention, that is, the conditions shown in the step (i) described later. In many cases, it exhibits liquid properties, and when cooled, it often exhibits solid or jelly-like properties. Here, a liquid-solid or jelly-like phase transition temperature is defined as a solidification temperature. The solidification temperature depends on the raw material composition and the amount of water, and thus cannot be defined unconditionally. When the solidification temperature is in such a preferable range, the sulfidizing agent mixture can be liquefied at a lower temperature, and transfer between apparatuses can be performed more easily.

  The sulfidizing agent mixture obtained by carrying out this step (i) is preferably uniform. Here, “homogeneous” is defined as a state in which no phase separation is observed when the mixture of the sulfidizing agent is heated to a temperature equal to or higher than the solidification temperature, and the solid content is not settled. Similarly, the state when solidified is assumed to be “uniform”. The heating temperature that is the standard for determining this “homogeneous” state varies depending on the type and amount of the sulfidizing agent and the organic polar solvent used, but cannot be clearly defined, but is higher than the solidification temperature of the sulfidizing agent mixture. I just need it. For example, when sodium hydrosulfide and sodium hydroxide are used as the sulfiding agent and N-methyl-2-pyrrolidone is used as the organic polar solvent, which is an example of a preferred embodiment of the present invention, 150 ° C. can be exemplified. . Further, “solid content” is defined as having a size larger than 1 mm, and “uniform” is defined as a state where it can be visually confirmed that it has not settled during heating. If the sulfidizing agent mixture is uniform, it can be recovered at a high recovery rate when the sulfidizing agent mixture heated and liquefied is transferred between containers, preferably 95% or more, more preferably 98% or more, Preferably, it can be recovered at a recovery rate of 99% or more. Similarly, the sulfur component in the sulfidizing agent mixture can be recovered with a recovery rate of preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more. Here, the recovery rate of the sulfur component in the sulfidizing agent mixture is the ratio of the amount of the sulfur component contained in the recovered sulfidizing agent mixture to the amount of the sulfur component charged in step (i). . When such a sulfidizing agent mixture is divided, it can be divided while maintaining the same composition. That is, if it is “homogeneous”, even if the sulfidizing agent mixture is in a solid, liquid or jelly state, it can be easily divided evenly. When the sulfidizing agent mixture is divided and used, Each time, it is possible to omit the trouble of performing composition analysis.

  As a method for obtaining a uniform sulfiding agent mixture, for example, sodium sulfide is used as a sulfiding agent, N-methyl-2-pyrrolidone is used as an organic polar solvent, and 5.9 moles of water and sulfide are added per mole of sulfur component of sodium sulfide. When a mixture containing 0.2 liter of N-methyl-2-pyrrolidone per mole of sodium sulfur component is prepared, a method of heating at 180 ° C. for 2 hours can be exemplified.

(5) Reaction mixture The reaction mixture in the production of the cyclic PAS of the present invention is a mixture containing at least the sulfidizing agent mixture, dihalogenated aromatic compound and organic polar solvent obtained in step (i). It refers to a mixture that forms cyclic polyarylene sulfide by subjecting it to the reaction conditions shown in the section of step (ii) described later. In addition to the above essential components, the reaction mixture may contain a third component that does not significantly inhibit the formation of cyclic PAS, a third component that has the effect of accelerating the formation of cyclic PAS, and linear PAS as described later. Is possible. In addition, after performing a process (ii) about a reaction mixture, suppose that a name is changed with a "reaction product."

(6) Cyclic polyarylene sulfide The cyclic polyarylene sulfide in the present invention is a cyclic compound having a repeating unit of formula:-(Ar-S)-as a main constituent unit, and preferably 80 mol of the repeating unit. % Or more of the compound represented by the following general formula (A).

  Here, examples of Ar can include units represented by the following general formulas (B) to (M), among which formulas (B) to (K) are preferable, and formulas (B) and (C) are preferred. More preferred is formula (B).

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same or different. May be good.)

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same or different. May be good.)

(In the formula, R1 and R2 are substituents selected from hydrogen, an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, and a halogen group, and R1 and R2 are the same or different. May be good.)

  In the cyclic polyarylene sulfide, the repeating units such as the above formulas (B) to (M) may be included at random, may be included as a block, or may be any mixture thereof. Typical examples of these include cyclic polyphenylene sulfide, cyclic polyphenylene sulfide sulfone, cyclic polyphenylene sulfide ketone, cyclic random copolymers containing these, cyclic block copolymers, and mixtures thereof. . Particularly preferred cyclic polyarylene sulfides include p-phenylene sulfide units as the main structural unit.

Is a cyclic polyphenylene sulfide containing 80 mol% or more, particularly 90 mol% or more (hereinafter sometimes abbreviated as cyclic PPS).

  Although there is no restriction | limiting in particular in the repeating number m in the said (A) formula of cyclic polyarylene sulfide, 2-50 are preferable, 3-40 are more preferable, and 4-30 can be illustrated as a still more preferable range. As will be described later, when the polyarylene sulfide prepolymer containing cyclic PAS is converted to a high degree of polymerization, it is preferable to heat at a temperature at which the cyclic polyarylene sulfide is melted or dissolved, Since the melting temperature of the cyclic polyarylene sulfide tends to increase as the value increases, the conversion of the polyarylene sulfide prepolymer to a high degree of polymerization can be performed at a lower temperature. The range is advantageous. The cyclic polyarylene sulfide may be either a single compound having a single repeating number or a mixture of cyclic polyarylene sulfides having different repeating numbers, but may be a mixture of cyclic polyarylene sulfides having different repeating numbers. The melt solution temperature tends to be lower than that of a single compound having a single number of repetitions, and the use of a mixture of cyclic polyarylene sulfides having different numbers of repetitions is used in the conversion to the above-mentioned high degree of polymerization. This is preferable because the temperature can be lowered.

(7) Linear polyarylene sulfide The linear polyarylene sulfide (hereinafter sometimes abbreviated as linear PAS) in the present invention is a straight chain having a repeating unit of the formula:-(Ar-S)-as a main structural unit. And a compound represented by the following general formula (N).

  Here, as Ar, as in the case of the above-described cyclic polyarylene sulfide, units represented by formula (B) to formula (M) and the like can be exemplified, among which formula (B) to formula (K) are preferable, Formula (B) and formula (C) are more preferable, and formula (B) is particularly preferable.

  In addition, linear PAS may contain repeating units, such as said Formula (B)-Formula (M), at random, may be contained in a block, and may be either of those mixtures. Typical examples of these include linear polyphenylene sulfide (hereinafter sometimes abbreviated as linear PPS), linear polyphenylene sulfide sulfone, linear polyphenylene sulfide ketone, cyclic random copolymers containing these, cyclic Examples thereof include block copolymers and mixtures thereof.

  Here, for example, a cyclic compound having a repetition number of m is considered to be generated by generating a linear compound having a repetition number of m and cyclizing with a certain probability. Therefore, the cyclic compound is constant unless the cyclization probability is 100%. A linear body is generated with probability. Therefore, in order to isolate and recover the cyclic PAS that is the object of the present invention, it is necessary to separate the cyclic PAS and the linear PAS. Regarding this separation operation, the higher the molecular weight of linear PAS, the more likely it is that cyclic PAS and linear PAS can be separated with higher precision. The preferred molecular weight of linear polyarylene sulfide is 2,500 or more in terms of weight average molecular weight. 5,000 or more is preferable, and 10,000 or more is more preferable. When the weight average molecular weight of the linear PAS is within this preferred range, the solubility of the linear PAS in the organic polar solvent decreases, while the cyclic PAS has a strong tendency to dissolve in the organic polar solvent. It is possible to efficiently obtain cyclic PAS from a mixture of cyclic PAS and linear PAS by utilizing the difference in solubility in water. Here, the weight average molecular weight is a value calculated in terms of polystyrene by gel permeation chromatography (GPC).

(8) Method for Producing Cyclic Polyarylene Sulfide The present invention is a method for producing cyclic PAS by heating a reaction mixture comprising at least a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent, wherein at least The present invention relates to a method for producing a cyclic polyarylene sulfide, which comprises the steps (i) and (ii).
(I) A mixture containing an organic polar solvent of 0.1 liter or more and less than 0.4 liter per mole of sulfur component of the sulfiding agent is heated, and the water content is 0.8 mole or more per mole of sulfur component of the sulfiding agent. Step (ii) of preparing 6.0 moles or less of the sulfidizing agent mixture After step (i), at least in the presence of the sulfidizing agent mixture and dihalogenated aromatic compound, the organic polar solvent is a sulfur in the reaction mixture. The process of heating on the conditions which become 1.25 liters-50 liters per mol of components Below, the cyclic PAS manufacturing method in this invention is explained in full detail.

  In the production of the cyclic PAS of the present invention, various known polymerization methods and reaction methods such as a batch method and a continuous method can be employed.

(8-1) Step (i)
Step (i) in the present invention is a step of preparing a sulfidizing agent mixture by heating a mixture containing at least a sulfidizing agent and an organic polar solvent under the following conditions.

  In the step (i) of the present invention, the organic polar solvent is contained in an amount of 0.1 to 0.4 liter per mole of the sulfur component of the sulfidizing agent. When the amount of the organic polar solvent is 0.4 liter or more per mole of the sulfur component of the sulfidizing agent, the solid content tends to precipitate and settle after the step (i), resulting in a heterogeneous system. However, when this is divided and transferred, it becomes extremely difficult to adjust the molar balance of the reaction mixture in the subsequent step (ii), and the reproducibility of the reaction results is lowered. On the other hand, when the amount of the organic polar solvent is less than 0.1 liter per mole of sulfur component of the sulfidizing agent, metal elution from the reactor occurs when a metal reactor is used as the reactor in the dehydration step. A tendency to increase is seen, and metal impurities get into the obtained cyclic PAS, resulting in deterioration of quality. Therefore, the upper limit of the amount of the organic polar solvent used in the step (i) needs to be less than 0.4 liter per mole of the sulfur component of the sulfidizing agent, preferably less than 0.30 liter, and less than 0.25 liter. More preferred is less than 0.21 liter. Further, the lower limit needs to be 0.1 liter or more per mole of sulfur component of the sulfidizing agent, preferably 0.12 liter or more, more preferably 0.15 liter or more, and further preferably 0.16 liter or more. It can be illustrated as In the above preferred range, a uniform sulfiding agent mixture can be obtained stably.

  Here, the resulting sulfidizing agent mixture is preferably uniform. If the sulfidizing agent mixture is uniform, it can be recovered at a high recovery rate when the sulfidizing agent mixture heated and liquefied is transferred between containers, preferably 95% or more, more preferably 98% or more, Preferably, it can be recovered at a recovery rate of 99% or more. Similarly, the sulfur component in the sulfidizing agent mixture can be recovered with a recovery rate of preferably 80% or more, more preferably 90% or more, and still more preferably 95% or more. Here, the recovery rate of the sulfur component in the sulfidizing agent mixture is the ratio of the amount of the sulfur component contained in the recovered sulfidizing agent mixture to the amount of the sulfur component charged in step (i). . When such a sulfidizing agent mixture is divided, it can be divided while maintaining the same composition, and when transferred, the raw material composition can be precisely adjusted.

  In the present invention, the amount of water after heating in step (i) needs to be 0.8 mol or more and 6.0 mol or less per mol of the sulfur component of the sulfidizing agent. When the amount of water after heating in step (i) is more than 6.0 mol per mol of sulfur component, the internal pressure of the system in step (ii) increases, and expensive pressure-resistant equipment is required. , Industrial disadvantages such as rapid progress of corrosion (blackening) of metal reactors occur. On the other hand, when the amount of water after heating in step (i) is less than 0.8 mole per mole of sulfur component, the solidification temperature of the resulting sulfidizing agent mixture is high, the transportability is lowered, and the liquid state High temperature is required for handling in the process, the raw material consumption rate during the implementation of step (ii) tends to be difficult to increase, and a purification operation to remove unreacted raw materials is necessary to improve the quality of cyclic PAS. Due to the heating, the sulfur component of the sulfiding agent is scattered as hydrogen sulfide and lost, which is disadvantageous for industrialization. In order to improve the above problems, the amount of water after heating in step (i) needs to be 0.8 mol or more and 6.0 mol or less per mol of the sulfur component, and the preferable upper limit is the sulfur component 1. 4.5 mol or less per mol, more preferably 3.0 mol or less can be exemplified, and a preferred lower limit is 0.9 mol or more, more preferably 1.0 mol or more per mol of sulfur component. In the above preferred range, the internal pressure of the system in step (ii) can be further reduced, and the solidification temperature of the sulfidizing agent mixture is in an appropriate range, so that a sulfidizing agent mixture having high transportability is obtained. It becomes possible.

  There is no restriction | limiting in particular about the moisture content before a heating in process (i), What kind of moisture content may be sufficient. However, in general, sulfidizing agents such as alkali metal sulfides are easily available as hydrates or aqueous mixtures containing 3 mol or more of water per mol of sulfur component, and sulfiding agents containing such water are also included. Is excellent in stability and tends not to be deteriorated particularly by oxygen. Therefore, it is preferable to use such a sulfidizing agent, and the preferable lower limit of the moisture content of the sulfidizing agent is preferably 0.8 mol or more, more preferably 3.0 mol or more per mol of the sulfur component, which is preferable. As an upper limit, it is 20 mol or less per mol of sulfur components, More preferably, 6.0 mol or less can be illustrated.

  As described above, in step (i), the amount of water before heating is not limited, and the amount of water after heating may be 0.8 mol or more and 6.0 mol or less per mol of the sulfur component of the sulfidizing agent. In step (i), any of a method in which dehydration is not performed and a method in which dehydration is performed can be employed, but a method of performing dehydration is more preferably employed. That is, in step (i), a mixture containing more than 6.0 moles of water per mole of sulfur component of the sulfiding agent is heated to dehydrate, and the amount of water is 0.8 mole per mole of sulfur component of the sulfiding agent. This is a method of reducing to 6.0 mol or less. When step (i) is carried out by such a preferred method, a sulfidizing agent mixture adjusted to an appropriate water content can be easily obtained even when a sulfidizing agent having a high water content, which is generally easily available, is used. It becomes possible. As a more preferable condition for dehydration, a method of heating a mixture containing more than 4.5 moles of water per mole of sulfur component of the sulfidizing agent to dehydrate to 0.8 to 4.5 moles. As a more preferable method, a method comprising heating a mixture containing more than 3.0 moles of water per mole of the sulfur component of the sulfidizing agent to dehydrate to 0.8 to 3.0 moles is reduced. Is mentioned. Under the preferable conditions described above, the internal pressure of the system in step (ii) can be further reduced.

  The heating condition in step (i) cannot be clearly specified because it varies depending on the combination of the sulfidizing agent and the organic polar solvent and the ratio of moisture, but the moisture content in the system is adjusted to the above range. The conditions under which a uniform sulfidizing agent mixture can be obtained are preferably employed. That is, examples of the temperature condition include 150 ° C. or higher, preferably 160 ° C. or higher, and more preferably 170 ° C. or higher. When the heating temperature in the step (i) is lower than the above-described preferable temperature, even when the amount of the organic polar solvent satisfies the above-described conditions, the solid content is precipitated at the end of the step (i) and the system is in a non-uniform state. However, it is possible to efficiently obtain a uniform sulfidizing agent mixture by setting the above-described preferable temperature conditions. As the temperature in step (i) is higher, the sulfur component of the sulfiding agent may be scattered as hydrogen sulfide or the raw material may be decomposed. Therefore, the upper limit is 250 ° C. or lower, preferably 230 ° C. Hereinafter, more preferably, 200 ° C. or less can be exemplified.

  The temperature condition at the stage of mixing the raw materials in step (i) is not particularly limited, but the lower limit is 0 ° C. or higher, preferably 10 ° C. or higher, and the upper limit is 150 ° C. or lower, preferably 100 ° C. or lower. The range can be exemplified. By mixing the raw materials in such a preferable range, it is possible to suppress problems such as alteration of the sulfidizing agent and organic polar solvent and composition change due to scattering of raw material components.

  There is no restriction | limiting in particular also about the pressure conditions in process (i), Any conditions of a normal pressure, pressure reduction, and pressurization are employable. However, when dehydration, which is a preferred operation in the step (i), is performed under normal pressure or reduced pressure in order to efficiently remove water. Here, the normal pressure is a pressure in the vicinity of the standard state of the atmosphere, and is an atmospheric pressure condition in which the temperature is approximately 25 ° C. and the absolute pressure is approximately 101 kPa.

  Further, the system atmosphere is preferably non-oxidizing conditions, and is preferably an inert gas atmosphere such as nitrogen, helium, and argon. In particular, from the viewpoint of economy and ease of handling, Is more preferable.

Here, since the step (ii) described later is performed a plurality of times, dividing the sulfidizing agent mixture prepared in the step (i) and using it in the subsequent step (ii) is a time required for the step (i). From the viewpoint of shortening and saving energy used in the process, this is a more preferable method. In this case, in order to perform accurate division, it is preferable that the uniformity and transportability of the sulfidizing agent mixture are high.
The transportability in the present invention is judged at a temperature at which the sulfidizing agent mixture obtained in step (i) can be transported without solidification, and when the solidification temperature is lower, it is judged that the transportability is high. In order to obtain a sulfidizing agent mixture having high transportability, it is important that the amount of water after heating in step (i) is 0.8 mol or more per mol of sulfur component. Thereby, the solidification temperature of the sulfidizing agent mixture obtained in step (i) is lowered, and the sulfidizing agent mixture can be transferred and divided at a lower temperature, which is preferable in terms of safety and energy cost. Although the temperature for judging the transportability varies depending on the type and composition of the raw material used, it cannot be defined unconditionally. However, the dihalogenated aromatic compound and the organic polarity are added to the sulfidizing agent mixture obtained in the subsequent step (ii). Considering the addition of a solvent, it is preferably a temperature at which the dihalogenated aromatic compound and the organic polar solvent are not scattered, that is, a temperature not higher than their boiling points. For example, when dichlorobenzene is used as the dihalogenated aromatic compound and N-methyl-2-pyrrolidone is used as the organic polar solvent, it is preferably 170 ° C. or lower, more preferably 150 ° C. or lower, and further preferably 130 ° C. or lower. The temperature described above is exemplary because it varies depending on the type of raw material used, but in the examples of the present invention, since dichlorobenzene and N-methyl-2-pyrrolidone are used, handling evaluation is performed at 130 ° C. It is carried out.

  In addition, when transferring the uniform sulfidizing agent mixture obtained in step (i) to another reactor, an organic polar solvent is added to the reactor in which step (i) was performed to dilute the uniform sulfidizing agent mixture in advance. This is the preferred method. By performing this operation, the fluidity of the uniform sulfiding agent mixture is increased and the transportability is also improved. Thereby, the measurement error at the time of adjusting the composition of the reaction mixture can be reduced. If this dilution operation is performed, the operation of recovering the uniform sulfidizing agent mixture obtained in step (i) from the container can be performed at a high recovery rate. As the amount of the organic polar solvent added in this dilution operation, the larger the dilution rate, the larger the required reactor, and the amount of the organic polar solvent used in the subsequent step (ii) is also limited. The amount of the organic polar solvent after the dilution operation is 50 liters or less, more preferably 20 liters or less, and even more preferably 15 liters or less per mole of the sulfur component. On the other hand, as a preferable lower limit, conditions of 0.4 liters or more, more preferably 0.8 liters or more, and further preferably 1.25 liters or more per mole of sulfur component can be exemplified. In addition, the dilution operation in the present invention includes not only the step of transferring the uniform sulfidizing agent mixture of step (i) described above to another reactor, but also a reactor for performing step (i) and step (ii). May be carried out after being transferred to different reactors, or may be carried out in several stages. In addition, the present invention includes a step of adjusting the dilute condition by adding an organic polar solvent between the steps (i) and (ii), but the above-described dilution operation may be used as an alternative.

(8-2) Step (ii)
The step (ii) in the present invention is a mixture obtained by mixing the sulfidizing agent mixture obtained in the step (i) with other components necessary for the production of the cyclic PAS and then heating under the conditions shown below. The process of synthesizing cyclic PAS. This step (ii) is sometimes called a reaction step.

  In step (ii), a reaction mixture is first prepared. Since the sulfidizing agent mixture obtained in step (i) already contains a sulfidizing agent and an organic polar solvent, the reaction mixture is obtained by adding at least a dihalogenated aromatic compound and an additional organic polar solvent thereto. To prepare.

  The amount of dihalogenated aromatic compound used in step (ii) is the molar balance between the dihalogenated aromatic compound and the sulfur component of the sulfidizing agent when linear PAS is not added as the third component in step (ii). And a condition of 0.9 mol or more per mol of sulfur component in the reaction mixture, preferably 0.92 mol or more, more preferably 0.94 mol or more. On the other hand, as an upper limit, the conditions of 1.5 mol or less per 1 mol of sulfur components in a reaction mixture can be illustrated, Preferably it is 1.2 mol or less, More preferably, it is 1.15 mol or less. By making the amount of dihalogenated aromatic compound used in the above range, cyclic PAS can be obtained in high yield, but when the amount is less than the above range, the yield of cyclic PAS tends to decrease, On the other hand, when the amount is larger than the above range, the amount of low molecular weight linear PAS increases, and when cyclic PAS is recovered by the method described later, it tends to be difficult to obtain with high purity. The amount of dihalogenated aromatic compound used here means the sum of the dihalogenated aromatic compounds charged in the reaction system, but the charged dihalogenated aromatic compounds are removed from the reaction system by scattering or the like. In this case, it means an amount obtained by subtracting the amount of the dihalogenated aromatic compound removed from the total.

  In step (ii), linear PAS may be added as the third component. The addition of linear PAS increases the yield of cyclic PAS produced relative to the amount of sulfiding agent and dihalogenated aromatic compound used. That is, the use amount of the sulfidizing agent and the dihalogenated aromatic compound used for obtaining the same amount of cyclic PAS can be saved, and the effect of being economically advantageous can be obtained. In this case, the linear PAS is considered to be equivalent to that obtained by reacting the dihalogenated aromatic compound with the sulfidizing agent, and the amount of the dihalogenated aromatic compound used can be determined in consideration of the amount of linear PAS to be added. . Therefore, the molar balance during the reaction when linear PAS is added needs to be adjusted by paying attention to the ratio of the number of moles of all arylene units to the number of moles of all sulfur components in the reaction mixture. Here, the total arylene unit in the reaction mixture is the total of the arylene unit contained in the linear PAS added to the arylene unit contained in the dihalogenated aromatic compound. The “mole number” of the arylene units contained in the linear PAS does not mean the number of PAS molecular chains, but means the sum of the “number of repeating units” in all the linear PAS components. For example, an arylene unit contained in one molecule of linear polyphenylene sulfide having a polymerization degree of 100 is regarded as 100 mol. The total sulfur component in the reaction mixture is the sum of the sulfur component contained in the sulfidizing agent and the sulfur component contained in the added linear PAS. Here, the “number of moles” of the sulfur component contained in the linear PAS is the “number of repeating units” of the polymer containing one sulfur atom. For example, one molecule of linear polyphenylene sulfide having a degree of polymerization of 100 is calculated as 100 mol, not 1 mol. As long as the essence of the present invention is not impaired, a compound containing a sulfur component in addition to the sulfidizing agent and linear PAS can be present in the reaction mixture. Sulfur-containing compounds that do not substantially act may not be considered as sulfur components.

  Examples of the conditions for obtaining cyclic PAS in high yield and high purity include a condition in which the number of moles of all arylene units is 0.9 mole or more per mole of all sulfur components in the reaction mixture, preferably 0.92 mol or more, more preferably 0.94 mol or more. On the other hand, as an upper limit, the conditions of 1.5 mol or less per 1 mol of all the sulfur components in a reaction mixture can be illustrated, Preferably it is 1.2 mol or less, More preferably, it is 1.15 mol or less. In such a preferable range, the yield and purity of the obtained cyclic PAS tend to be higher.

  Further, the amount of the linear PAS sulfidizing agent used relative to the sulfur component can be exemplified by 0 mol or more, preferably 0.1 mol or more, more preferably, as a lower limit with respect to 1 mol of the sulfur component derived from the sulfidizing agent. 1 mole or more. On the other hand, as an upper limit, 20 mol or less can be illustrated, Preferably it is 10 mol or less, More preferably, it is 5 mol or less. In such a preferable range, the reaction between the linear PAS and the sulfidizing agent is likely to proceed, so that the efficiency of producing the cyclic PAS from the linear PAS can be further increased.

  In addition, the manufacturing method of the linear PAS added here is not particularly limited, and any manufacturing method can be used, and a wide range of molded products and wastes, waste plastics and off-spec products using PAS can be used. Although it can be used, a method using linear PAS by-produced in the production process of cyclic PAS is most preferable. In the production of a cyclic compound, since a large amount of linear PAS is produced as a byproduct, this method is economically very preferable in that it can be used without waste.

  The molecular weight of the linear PAS contained in the reaction mixture before step (ii) is not particularly limited. For example, the lower limit of the weight average molecular weight can be 5,000 or more, preferably 7,500 or more. 10,000 or more are more preferable. Moreover, as an upper limit, 1,000,000 or less can be illustrated, 500,000 or less is preferable and 100,000 or less is more preferable. In general, the lower the weight average molecular weight, the higher the solubility in an organic polar solvent, so there is the advantage that the time required for the reaction can be shortened. Moreover, there is no restriction | limiting in particular also in the form of linear PAS contained in the reaction mixture before performing a process (ii), A dry powder form, a granular form, a granular form, a pellet form may be sufficient, and the organic which is a reaction solvent It is also possible to use it in a state containing a polar solvent, and it is also possible to use it in a state containing a third component that essentially does not inhibit the reaction. Examples of such a third component include inorganic fillers and alkali metal halides. Here, the weight average molecular weight is a value calculated in terms of polystyrene by gel permeation chromatography (GPC).

  The amount of the organic polar solvent used in the step (ii) is determined in consideration of the amount used when the dilution operation is performed before the transfer of the sulfidizing agent obtained in the step (i). Thus, the amount is adjusted to 1.25 liters to 50 liters per mole of sulfur component in the reaction mixture. Here, the amount of the organic polar solvent used is an amount obtained by subtracting the amount of the organic polar solvent removed from the reaction system from the amount of the organic polar solvent introduced into the reaction system on the basis of the volume of the solvent at normal temperature and pressure. Point to. When the amount of the organic polar solvent is less than 1.25 liters per mole of the sulfur component, the yield of cyclic PAS is greatly reduced, and the amount of the organic polar solvent is 50 per mole of the sulfur component. When the amount is more than 1 liter, the amount of cyclic PAS obtained from the reaction solution per unit volume decreases. However, by using the amount of the organic polar solvent within the above range, cyclic PAS can be produced at a production rate of 3% or more. Under the preferable conditions of the present invention, it can be obtained at 5% or more, more preferably 6% or more, even more preferably 7% or more, and even more preferably 8% or more. Further, in order to increase the productivity of cyclic PAS by increasing the amount of cyclic PAS obtained from the reaction solution per unit volume, as a preferred lower limit of the amount of organic polar solvent used, 1 mol per mole of sulfur component in the reaction mixture. The conditions may be 4 liters or more, more preferably 1.65 liters or more, and even more preferably 2.0 liters or more, and the preferred upper limit is 20 liters or less per mole of sulfur component in the reaction mixture, more preferably A condition of 15 liters or less can be exemplified.

  In general, the production of a cyclic compound often requires more solvent than the above range, and the cyclic compound is often not efficiently obtained within the preferred range of the present invention. As will be described later, in the present invention, a temperature exceeding the reflux temperature of the organic polar solvent is adopted as a preferred reaction temperature. In this case, however, the conditions for using a smaller amount of the solvent than in the case of producing a general cyclic compound are used. That is, cyclic PAS tends to be efficiently obtained even in the range near the lower limit of the solvent usage described above. The reason for this is not clear at this time, but it is presumed that when the reaction is performed at a high temperature that cannot be reached under atmospheric pressure conditions, the consumption rate of the raw material is extremely high, which favorably acts on the generation of the cyclic compound. .

  The heating condition in step (ii) is not particularly limited as long as it is a temperature and time for producing cyclic PAS, but the reaction temperature is preferably higher than the reflux temperature under normal pressure of the organic polar solvent used. This temperature varies depending on the type of the organic polar solvent and varies depending on the types and amounts of the components in the reaction mixture, and thus cannot be uniquely determined. However, in the preferred embodiment of the present invention, the lower limit is 120. C. or higher can be exemplified, preferably 180.degree. C. or higher, more preferably 220.degree. C. or higher, still more preferably 225.degree. C. or higher, and still more preferably 240.degree. C. or higher. The upper limit may be 350 ° C. or less, preferably 320 ° C. or less, more preferably 310 ° C. or less, still more preferably 300 ° C. or less, and even more preferably 280 ° C. or less. By setting the reaction temperature to such a preferable range, a high reaction rate can be obtained, and cyclic PAS tends to be efficiently obtained. Here, the normal pressure is a pressure in the vicinity of the standard state of the atmosphere, and is an atmospheric pressure condition in which the temperature is approximately 25 ° C. and the absolute pressure is approximately 101 kPa. The reflux temperature is a temperature at which the liquid component of the reaction mixture repeats boiling and condensation.

  In the present invention, the reaction mixture is preferably heated above the reflux temperature under normal pressure. However, as a method for treating the reaction mixture in such a heated state, for example, a method in which the reaction mixture is heated under a pressure environment exceeding normal pressure. As a method for easily constructing this high-pressure environment, a method of heating the reaction mixture in a sealed reactor can be exemplified.

  The temperature control method during heating may be any of a method of maintaining a constant temperature, a method of increasing the temperature stepwise, or a method of continuously changing the temperature.

  On the other hand, the reaction time depends on the type and amount of the raw material used or the reaction temperature, and thus cannot be defined unconditionally. However, a preferable lower limit is 0.1 hour or more, more preferably 0.5 hour or more. By setting the reaction time to be equal to or longer than this preferable time, unreacted raw material components can be sufficiently reduced, and thus the produced cyclic PAS tends to be easily recovered. In addition, since the reaction method of the present invention has a characteristic that an extremely high reaction rate can be obtained, the reaction proceeds sufficiently even within 40 hours, preferably 10 hours or less, more preferably 6 hours or less.

  The pressure condition in step (ii) cannot be uniquely defined because it varies depending on the raw materials constituting the reaction mixture, its composition, reaction temperature, etc., but it is a preferred embodiment of the present invention under normal pressure of the reaction mixture. In order to carry out the reaction at a temperature exceeding the reflux temperature, the pressure of the system is preferably set to a pressure exceeding the normal pressure. Specifically, the lower limit of the gauge pressure is preferably 0.05 MPa or more, more preferably 0.1 MPa or more, still more preferably 0.2 MPa or more, and still more preferably 0.3 MPa or more. The upper limit is preferably 0.8 MPa or less, more preferably 0.7 MPa or less, and still more preferably 0.5 MPa or less. In such a preferable pressure range, the time required for producing the cyclic PAS tends to be shortened.

  In the above preferred pressure range, an expensive pressure-resistant manufacturing facility is not required, so that the equipment cost required for manufacturing the cyclic PAS can be reduced and the safety is also high. The gauge pressure referred to here is a relative pressure based on the atmospheric pressure, and is a pressure value obtained by subtracting the atmospheric pressure from the absolute pressure. Further, the system atmosphere is preferably non-oxidizing conditions, and is preferably an inert gas atmosphere such as nitrogen, helium, and argon. In particular, from the viewpoint of economy and ease of handling, Is more preferable. Furthermore, you may implement pressurization operation by an inert gas in the range which does not exceed the said upper limit of the said preferable pressure.

  Here, the container in which the step (ii) is performed is not particularly limited, and may be performed in the same reactor as the reactor in which the step (i) is performed, or may be performed in a separate reactor. Considering that the preferred heating conditions and pressure conditions of i) and step (ii) are different, it is preferable to perform step (i) and step (ii) in separate reactors. By separating the reactors in this way, it is possible to incorporate a continuous process into the reaction, and it is possible to produce cyclic PAS more efficiently. Alternatively, a third container may be provided separately, and only the preparation of the raw material is performed in the container, and then the process (ii) may be performed after transferring to the reactor in which the process (ii) is performed. In addition, although what kind of reactor may be used, since it is desirable to perform reaction, stirring, it is preferable that it was equipped with the stirrer.

  The amount of water in the reaction mixture in the step (ii) is an effect obtained by carrying out the step (i), and is 0.8 mol or more and 6.0 mol or less per mol of the sulfur component, unless particularly an additional operation is performed. Become. As long as this condition is satisfied, the raw material consumption rate after the implementation of step (ii) can be increased.

  However, as described above, the preferable upper limit of the amount of water that gives a more preferable effect is 4.5 mol or less per mol of the sulfur component, more preferably 3.0 mol or less, and the preferable lower limit is 0 per mol of the sulfur component. Since it is 0.9 mol or more, more preferably 1.0 mol or more, the water content can be readjusted by removing or adding water in order to make such a range. The amount of water in the reaction mixture in the present invention refers to the sulfidizing agent, dihalogenated aromatic compound and organic polar solvent charged in the reaction system, and other components including those components when other components are charged. This refers to the amount of water obtained by subtracting the amount of water removed from the system by additional operations such as dehydration from the total amount of water introduced and not included, and does not take into account the water generated during the mixing and reaction of the above components. .

  In addition, when the water content in the step (i) is reduced to less than 0.8 mol per mol of the sulfur component of the sulfidizing agent, the amount of the organic polar solvent used in the step (ii) is 2 per mol of the sulfur component. Under low concentration conditions exceeding 5 liters, there is a tendency that raw materials are not easily consumed, but by setting the water content in step (i) to 0.8 mol or more per mol of sulfur component of the sulfidizing agent, It is possible to maintain a high raw material consumption rate even in such a low concentration region.

Here, the raw material consumption rate in the present invention refers to the conversion rate of the sulfiding agent, and the formula for calculating the conversion rate of the sulfiding agent is:
Conversion (%) = [[Sulphidating agent charge (mol) -Sulphidating agent remaining amount (mol)] / [Sulphidating agent charge (mol)]] × 100%.
It is represented by In addition, when linear PAS is included in the reaction mixture before heating in the step (ii), the raw material consumption rate is evaluated based on the conversion rate of all sulfur components, and the calculation formula is the conversion rate ( %) = [[Total sulfur component in the reaction mixture (mol) -residual amount of sulfidizing agent (mol)] / [total sulfur component in the reaction mixture (mol)]] × 100%.
It is represented by Here, the remaining amount of the sulfiding agent can be measured by ion chromatography or the like.

  In order to prevent the unreacted raw material from entering the isolated cyclic PAS when the cyclic PAS produced by carrying out the step (ii) is recovered by the method exemplified in (9) described later. The higher the raw material consumption rate, the better. However, the preferable lower limit can be 95% or more, more preferably 97% or more, and still more preferably 98% or more. As described above, in the conventional technique shown in Patent Document 4, the raw material consumption rate could not be increased to such a preferable range, but the above-mentioned preferable range can be obtained by satisfying the implementation condition of the present invention. It has become possible. In addition, there is no restriction | limiting in particular in an upper limit, and 100% which consumes all the raw materials charged is the most preferable.

  Further, in the step (ii), it is also possible to continue the reaction by adding a sulfidizing agent and a dihalogenated aromatic compound at an optional stage where the reaction has proceeded and the raw materials have been consumed to some extent. It is important to consider the amount of the sulfidizing agent in the reaction mixture before the addition, and the organic polar solvent is added to 1 mol of the sulfur component in the reaction mixture after the additional operation of the sulfidizing agent. It is desirable to maintain 1.25 liters or more. The amount of the sulfidizing agent in the reaction mixture can be calculated from the result of the conversion rate of the sulfidizing agent.

  As described above, the addition of the sulfidizing agent and the dihalogenated aromatic compound may be performed at an optional stage in which the charged raw materials are reduced. However, a stage where the conversion rate of the sulfidizing agent is 50% or more is preferable. 70% or more is more preferable, and cyclic PAS can be obtained more efficiently by adding at such a stage.

  There is no limit to the number of times such addition of the sulfidizing agent and the dihalogenated aromatic compound is performed, but usually the sum of the sulfidizing agent and the added sulfiding agent in the reaction system at the start of the reaction is the total amount in the reaction mixture. A preferable range is an amount of up to 10 moles per liter of the organic polar solvent based on the sulfur atom of the sulfiding agent. Here, the addition of the sulfidizing agent and the dihalogenated aromatic compound is a preferable method because it has the effect of increasing the amount of the product in the reaction mixture and can increase the yield of cyclic PAS per unit volume.

  In addition, when the amount of water in the reaction mixture changes due to the addition of the sulfidizing agent and the dihalogenated aromatic compound, it is possible to perform an additional operation so that the above-mentioned preferable amount of water is obtained. It is also desirable to remove any amount of water from the reaction mixture after addition. In the removal of water, when components other than water are removed from the reaction mixture, a sulfidizing agent, a dihalogenated aromatic compound, and an organic polar solvent can be further added as necessary. The operation of returning the components to the reaction mixture may be performed again.

  The cyclic PAS production rate is calculated by first preparing a calibration curve by performing high performance liquid chromatography analysis on the cyclic PAS sample, and using the calibration curve, the cyclic PAS is calculated from the peak area of the cyclic PAS. The content was calculated, and the production rate of cyclic PAS was calculated as the actual cyclic PAS content relative to the cyclic PAS yield assuming that all sulfur components in the reaction mixture were converted to cyclic PAS. In addition, when linear PAS is included in the reaction mixture before heating in step (ii), the cyclic PAS yield when it is assumed that all sulfur components in the reaction mixture are all converted to cyclic PAS. The production rate of cyclic PAS was calculated as the actual cyclic PAS content.

(9) Method for recovering cyclic polyarylene sulfide In the production of cyclic PAS of the present invention, it is also possible to separate and recover cyclic PAS from the reaction product obtained by the reaction described above. The reaction product obtained by the reaction contains cyclic PAS, linear PAS and organic polar solvent, and as other components, unreacted sulfidizing agent, dihalogenated aromatic compound, water, by-product salt, etc. May be included.

  Although there is no restriction | limiting in particular in the method of collect | recovering cyclic PAS from this reaction product, For example, the collection method shown by patent document 4 can be illustrated. By using such a method, cyclic PAS can be easily recovered with high purity. In addition, due to the effects of the present invention, the unreacted sulfidizing agent and dihalogenated aromatic compound contained in the reaction product are reduced as compared with the prior art, so that a higher-purity cyclic PAS is obtained. It is possible.

(10) Properties of the cyclic PAS of the present invention The cyclic PAS thus obtained usually has a high purity containing 50% by weight or more, preferably 70% by weight or more, more preferably 80% by weight or more of the cyclic PAS. Therefore, it has high utility value even industrially having characteristics different from generally obtained linear PAS. In addition, the cyclic PAS obtained by the production method of the present invention is characterized in that m in the formula (A) is not single, and the formula (A) having m different from m = 2 to 50 is easily obtained. . Here, the preferable range of m is 3 to 40, more preferably 4 to 30. When m is in this range, as will be described later, when cyclic PAS is used as a raw material for obtaining PAS, the polymerization reaction tends to proceed, and a high molecular weight product tends to be obtained. The reason for this is not clear at present, but it is assumed that cyclic PAS in this range has a large bond distortion due to the cyclic nature of the molecule, and is likely to have a high molecular weight during polymerization.

  In addition, since cyclic PAS having a single m is obtained as a single crystal, it has a very high melting temperature. However, in the present invention, cyclic PAS is easy to obtain a mixture having different m, and thus melting of cyclic PAS There is a feature that the temperature is low, which expresses an excellent feature that, for example, the heating temperature when the cyclic PAS is melted and used can be lowered.

(11) Resin composition blended with cyclic PAS of the present invention The cyclic PAS obtained according to the present invention can be blended with various resins and used, and a resin composition blended with such a cyclic PAS. Has a strong tendency to exhibit excellent fluidity during melt processing, and tends to have excellent residence stability. In addition, there is no restriction | limiting in particular in the method of manufacturing the resin composition which mix | blended cyclic PAS obtained by this invention, For example, the manufacturing method of the resin composition shown by patent document 4 can be illustrated.

(12) Conversion of cyclic PAS to a high degree of polymerization The cyclic PAS produced according to the present invention has excellent characteristics as described in (10), and therefore should be suitably used as a prepolymer for obtaining a polymer. Is possible. Here, as the prepolymer, the cyclic PAS obtained by the cyclic PAS production method of the present invention may be used alone or may contain a predetermined amount of other components, but if it contains components other than the cyclic PAS, A PAS component such as a linear PAS or a PAS having a branched structure is particularly preferable. A polyarylene sulfide prepolymer that contains at least the cyclic PAS of the present invention and can be converted into a high polymerization degree by the method exemplified below is sometimes referred to as a PAS prepolymer.

  The conversion reaction of cyclic PAS to a high degree of polymerization may be performed under conditions where a component having a higher molecular weight than the molecular weight of cyclic PAS is generated from cyclic PAS. A method of heating a PAS prepolymer containing the formula PAS to convert it to a high degree of polymerization can be exemplified as a preferred method. The heating temperature is preferably a temperature at which the PAS prepolymer melts, and there is no particular limitation as long as it is such a temperature condition. If the heating temperature is lower than the melt solution temperature of the PAS prepolymer, a long time tends to be required to obtain a PAS having a high molecular weight. Although the temperature at which the PAS prepolymer melts varies depending on the composition and molecular weight of the PAS prepolymer and the environment during heating, it cannot be uniquely indicated. For example, the PAS prepolymer is a differential scanning calorimeter. It is possible to grasp the melting solution temperature by analyzing with. If the heating temperature is too high, undesirable side reactions such as cross-linking reactions and decomposition reactions between PAS prepolymers, between PASs produced by heating, and between PAS and polyarylene sulfide prepolymers tend to occur. Therefore, it is desirable to avoid a temperature at which such an undesirable side reaction is prominent because the properties of the obtained PAS may deteriorate. As the heating temperature at which the manifestation of such undesirable side reactions is easily suppressed, the lower limit can be exemplified by 180 ° C. or higher, preferably 200 ° C. or higher, more preferably 250 ° C. or higher, and the upper limit exemplified by 400 ° C. or lower. The temperature is preferably 380 ° C. or lower, more preferably 360 ° C. or lower. On the other hand, if there is no problem even if a certain degree of side reaction occurs, the lower limit can be exemplified by 250 ° C. or higher, preferably 280 ° C. or higher, and the upper limit can be exemplified by 450 ° C. or lower, preferably 420 ° C. or lower. Selectable. In such a preferable range, there is an advantage that the conversion to a high molecular weight can be performed in a very short time.

  The time for performing the heating cannot be uniformly defined because it varies depending on various properties such as the content and m number of the cyclic PAS in the PAS prepolymer to be used and the molecular weight, and the conditions such as the temperature of the heating. It is preferable to set so that the undesirable side reaction does not occur as much as possible. Therefore, the lower limit of the heating time can be exemplified by 0.05 hours or more, preferably 0.1 hours or more. On the other hand, the upper limit may be 100 hours or less, preferably 20 hours or less, more preferably 10 hours or less. If it is less than 0.05 hours, the conversion of the PAS prepolymer to PAS tends to be insufficient, and if it exceeds 100 hours, the possibility of adverse effects on the properties of the resulting PAS due to undesirable side reactions increases. There may be economic disadvantages.

  In addition, various catalyst components that promote the conversion can be used for the PAS prepolymer upon conversion to a high degree of polymerization by heating. Examples of such catalyst components include ionic compounds and compounds having radical generating ability. Examples of the ionic compound include sulfur alkali metal salts such as sodium salt and lithium salt of thiophenol, and examples of the compound having a radical generating ability include compounds that generate sulfur radicals by heating. Specific examples include compounds containing a disulfide bond. When various catalyst components are used, the catalyst component is usually taken into PAS, and the obtained PAS often contains the catalyst component. In particular, when an ionic compound containing an alkali metal and / or other metal component is used as a catalyst component, most of the metal component contained therein tends to remain in the obtained PAS. In addition, PAS obtained using various catalyst components tends to increase in weight loss when PAS is heated. Therefore, when a higher purity PAS is desired and / or when a PAS with less weight loss when heated is desired, it is preferable to use as little catalyst components as possible and more preferably not to use them. Therefore, when converting the PAS prepolymer to a high degree of polymerization using various catalyst components, the amount of alkali metal in the reaction system containing the PAS prepolymer and the catalyst component is 100 ppm or less, preferably 50 ppm or less, more preferably Is 30 ppm or less, more preferably 10 ppm or less, and the disulfide weight based on the total sulfur weight in the reaction system is less than 1% by weight, preferably less than 0.5% by weight, more preferably less than 0.3% by weight, It is preferable to adjust the addition amount of the catalyst component so that it is preferably less than 0.1% by weight.

  The conversion of the PAS prepolymer to a high degree of polymerization by heating is usually carried out in the absence of a solvent, but can also be carried out in the presence of a solvent. The solvent is not particularly limited as long as it does not substantially cause undesirable side reactions such as inhibition of conversion to a high degree of polymerization by heating of the PAS prepolymer and decomposition or crosslinking of the produced PAS. Nitrogen-containing polar solvents such as methyl-2-pyrrolidone, dimethylformamide, dimethylacetamide, sulfoxide / sulfone solvents such as dimethyl sulfoxide, dimethyl sulfone, ketone solvents such as acetone, methyl ethyl ketone, diethyl ketone, acetophenone, dimethyl ether, dipropyl ether , Ether solvents such as tetrahydrofuran, halogen solvents such as chloroform, methylene chloride, trichloroethylene, ethylene chloride, dichloroethane, tetrachloroethane, chlorobenzene, methanol, ethanol, propylene Lumpur, butanol, pentanol, ethylene glycol, propylene glycol, phenol, cresol, alcohol phenol based solvents such as polyethylene glycol, benzene, toluene, and aromatic hydrocarbon solvents such as xylene. It is also possible to use an inorganic compound such as carbon dioxide, nitrogen, or water as a solvent in a supercritical fluid state. These solvents can be used as one kind or a mixture of two or more kinds.

  The conversion of the PAS prepolymer to a high degree of polymerization by heating may be performed in a mold for producing a molded product, as well as by a method using a normal polymerization reaction apparatus, an extruder, Any apparatus equipped with a heating mechanism, such as a melt kneader, can be used without particular limitation, and known methods such as a batch method and a continuous method can be employed.

  The atmosphere during the conversion of the PAS prepolymer to a high degree of polymerization by heating is preferably a non-oxidizing atmosphere, and is also preferably performed under reduced pressure. Moreover, when it carries out under pressure reduction conditions, it is preferable to make it the pressure reduction conditions after making the atmosphere in a reaction system once non-oxidizing atmosphere. Thereby, it is in the tendency which can suppress generation | occurrence | production of undesirable side reactions, such as a crosslinking reaction and a decomposition reaction between PAS prepolymers, between PAS produced | generated by heating, and between PAS and a PAS prepolymer. Note that the non-oxidizing atmosphere is an atmosphere in which the oxygen concentration in the gas phase in contact with the PAS component is 5% by volume or less, preferably 2% by volume or less, more preferably an oxygen-free atmosphere, that is, nitrogen, helium, argon, etc. This indicates an inert gas atmosphere, and among these, a nitrogen atmosphere is particularly preferred from the viewpoint of economy and ease of handling. The reduced pressure condition means that the reaction system is lower than the atmospheric pressure, and the upper limit is preferably 50 kPa or less, more preferably 20 kPa or less, and even more preferably 10 kPa or less. An example of the lower limit is 0.1 kPa or more, and 0.2 kPa or more is more preferable. When the decompression condition exceeds the preferable upper limit, an undesirable side reaction such as a crosslinking reaction tends to occur easily. It tends to evaporate easily.

  The conversion of the PAS prepolymer to a high degree of polymerization can also be performed in the presence of a fibrous substance. Here, the fibrous substance is a thin thread-like substance, and an arbitrary substance having a structure elongated like a natural fiber is preferable. By converting the PAS prepolymer to a high polymerization degree in the presence of the fibrous substance, a composite material structure composed of PAS and the fibrous substance can be easily prepared. Since such a structure is reinforced by a fibrous substance, it tends to be superior in mechanical properties, for example, compared to the case of PAS alone.

  Here, among the various fibrous materials, it is preferable to use reinforcing fibers made of long fibers, which makes it possible to highly reinforce PAS. In general, when creating a composite material structure composed of a resin and a fibrous substance, the resin and the fibrous substance tend to become poorer due to the high viscosity when the resin is melted. In many cases, composite materials cannot be produced or expected mechanical properties do not appear. Here, wetting is the physical state of the fluid material and the solid substrate so that substantially no air or other gas is trapped between the fluid material such as a molten resin and the solid substrate such as a fibrous compound. It means that there is good and maintained contact. Here, the lower the viscosity of the fluid substance, the better the wetting with the fibrous substance. Since the viscosity of the PAS prepolymer of the present invention when melted is significantly lower than that of a general thermoplastic resin such as PAS, the wettability with the fibrous material tends to be good. After the PAS prepolymer and the fibrous material form good wetting, the PAS prepolymer is converted into a high degree of polymerization according to the PAS production method of the present invention, so that the fibrous material and the high degree of polymerization (polyarylene) It is possible to easily obtain the composite material structure in which the sulfide is formed with good wetting.

As described above, it is preferable that the fibrous material is a reinforcing fiber composed of long fibers, and the reinforcing fiber used in the present invention is not particularly limited. However, as the reinforcing fiber suitably used, generally, a high-performance reinforcing fiber is used. And fibers having good heat resistance and tensile strength. For example, the reinforcing fiber includes glass fiber, carbon fiber, graphite fiber, aramid fiber, silicon carbide fiber, alumina fiber, and boron fiber. Among these, carbon fiber and graphite fiber, which have good specific strength and specific elastic modulus and have a great contribution to weight reduction, can be exemplified as the best. Any type of carbon fiber or graphite fiber can be used as the carbon fiber or graphite fiber depending on the application, but high strength and high elongation carbon having a tensile strength of 450 kgf / mm ² and a tensile elongation of 1.6% or more. Fiber is most suitable. In the case of using long fiber-like reinforcing fibers, the length is preferably 5 cm or more. In the range of this length, it becomes easy to sufficiently develop the strength of the reinforcing fiber as a composite material. Carbon fibers and graphite fibers may be used in combination with other reinforcing fibers. Moreover, the shape and arrangement | sequence of a reinforced fiber are not limited, For example, even if it is a single direction, a random direction, a sheet form, a mat form, a textile form, and a braid form, it can be used. In particular, for applications that require high specific strength and specific elastic modulus, an array in which reinforcing fibers are aligned in a single direction is most suitable. Arrangements are also suitable for the present invention.

  The conversion of the PAS prepolymer to a high degree of polymerization can also be performed in the presence of a filler. Examples of the filler include non-fibrous glass, non-fibrous carbon, and inorganic fillers such as calcium carbonate, titanium oxide, and alumina.

  The present invention will be specifically described below with reference to examples. These examples are illustrative and not limiting.

<Measurement of formation rate of cyclic polyphenylene sulfide>
The production rate of the cyclic polyphenylene sulfide compound in the reaction product was measured using HPLC. The measurement conditions for HPLC are shown below.
Apparatus: LC-10Avp series manufactured by Shimadzu Corporation Column: Mightysil RP-18 GP150-4.6 (5 μm) manufactured by Kanto Chemical Co., Inc.
Detector: Photodiode array detector (wavelength 270 nm)

  The structure of each component divided by HPLC was determined by analysis by LC-MS and MALDI-MS, NMR, and IR measurement of the fraction obtained by preparative LC.

  The cyclic PAS production rate is calculated by first preparing a calibration curve by performing high performance liquid chromatography analysis on the cyclic PAS sample, and using the calibration curve, the cyclic PAS is calculated from the peak area of the cyclic PAS. The content was calculated, and the production rate of cyclic PAS was calculated as the actual cyclic PAS content relative to the cyclic PAS yield assuming that all sulfur components in the reaction mixture were converted to cyclic PAS. In addition, when linear PAS is included in the reaction mixture before heating in step (ii), the cyclic PAS yield when it is assumed that all sulfur components in the reaction mixture are all converted to cyclic PAS. The production rate of cyclic PAS was calculated as the actual cyclic PAS content.

<Analysis of sulfiding agent>
Quantification of the sulfidizing agent in the reaction mixture and reaction product (for example, quantification of sodium hydrosulfide) was carried out using ion chromatography under the following conditions.
Apparatus: HIC-20 Asper made by Shimadzu Corporation
Column: Shimadzu Shim-pack IC-SA2 (250 mm × 4.6 mm ID)
Detector: Electrical conductivity detector (suppressor)
Eluent: 4.0 mM sodium bicarbonate / 1.0 mM aqueous sodium carbonate flow rate: 1.0 ml / min Injection volume: 50 microliters Column temperature: 30 ° C.

  After adding hydrogen peroxide solution to the sample and oxidizing the sulfide ions contained in the sample, it was quantified as sulfate ion by the above analysis, and the untreated sample without adding hydrogen peroxide solution was analyzed. The amount of sulfide ion in the sample was calculated by subtracting the sulfate ion quantitative value. The amount of sulfide ion calculated here was used as the amount of unreacted sulfidizing agent, and the sulfidizing agent consumption rate in the reaction, that is, the raw material consumption rate, was calculated from the ratio with the amount of sulfidizing agent charged.

<Uniformity determination and solidification temperature measurement of sulfidizing agent mixture>
To measure the solidification temperature of the sulfidizing agent mixture and determine its homogeneity, first take 2 g of room temperature sulfidizing agent mixture in a glass sample bottle and heat it until it melts in an oil bath without stirring. It was confirmed. Subsequently, it was taken out from the oil bath, a temperature sensor was inserted, and the temperature at which it started to solidify visually after standing and cooling in a room temperature environment was measured. The accuracy was performed in increments of 5 ° C. The fluctuation range of the solidification temperature varies depending on the composition of the sulfidizing agent mixture, but cannot be generally stated. For example, the water content in the sulfidizing agent mixture has changed from 3 mol to 2.5 mol per mol of sulfur component. In some cases, the solidification temperature tends to increase by 5 ° C.

<Molecular weight measurement>
The weight average molecular weight Mw of the linear polyphenylene sulfide was calculated in terms of polystyrene by gel permeation chromatography (GPC) which is a kind of size exclusion chromatography (SEC). The measurement conditions for GPC are shown below.
Equipment: Senshu Science SSC-7100
Column name: Senshu Science GPC3506
Eluent: 1-chloronaphthalene detector: differential refractive index detector Column temperature: 210 ° C
Pre-constant temperature: 250 ° C
Pump bath temperature: 50 ° C
Detector temperature: 210 ° C
Flow rate: 1.0 mL / min
Sample injection amount: 300 μL (slurry: about 0.2% by weight)

[Example 1]
<Process (i)>
A distillation tower was attached to the top of an autoclave with a stirrer made of SUS316, and a cooling pipe and a container for receiving condensate were installed at the top. In an autoclave, 46.7 g of a 48 wt% sodium hydrosulfide aqueous solution (0.400 mol as sodium hydrosulfide), 35.0 g of a 48 wt% sodium hydroxide aqueous solution (0.420 mol as sodium hydroxide), N-methyl -2-pyrrolidone (NMP) 82.0 g (0.0799 liter) was charged. The amount of water contained in the raw material was 42.5 g (2.36 mol), and the amount of water per mol of the sulfur component of the sulfidizing agent was 5.90 mol. The amount of the organic polar solvent per mole of sulfur component of the sulfiding agent was 0.200 liter.

  The mixture was heated from room temperature to 180 ° C. with stirring through nitrogen at normal pressure. When 16.6 g of dehydrated distillate was obtained, the heating was stopped and the mixture was cooled to 130 ° C. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 3.1 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 29.0 g (1.610 mol). )Met. Further, from the results of ion chromatography, it was found that the sulfur component scattered as hydrogen sulfide during the dehydration step was 0.0004 mol, and as a result, the sulfur component remaining in the system was 0.399 mol. I understood it. Therefore, it was found that the amount of water in the system was 4.03 mole per mole of sulfur component.

<Process (ii)>
Open the raw material inlet of the autoclave in which step (i) was performed, and add 59.8 g (0.407 mol) of p-dichlorobenzene (p-DCB) and 945 g (0.921 liters) of NMP to the reaction system. The amount of NMP per mole of sulfur component was adjusted to 2.50 liters. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure was 0.65 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 97.3%, and all of the sulfidizing agent in the reaction mixture was all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 15.1%.

  Further, only the step (i) of Example 1 was carried out separately, and uniformity determination and solidification temperature measurement were performed on the sulfidizing agent mixture recovered after cooling to room temperature. As a result, the solidification temperature was 100 ° C. In the above, it was confirmed that no sedimentation of solid content was observed. Therefore, it was found that this mixture of sulfiding agents was uniform and exhibited high transportability at 100 ° C. or higher.

  According to the method for producing the cyclic polyarylene sulfide of the present invention, the cyclic polyarylene sulfide can be obtained in a high yield, and the raw material consumption rate is high, and there is almost no raw material loss.

[Comparative Example 1]
Here, an example is shown in which cyclic PAS is manufactured according to the example of Patent Document 3 (Japanese Patent Laid-Open No. 2009-30012). That is, an example is shown in which cyclic PAS is produced under the same reaction vessel, reaction concentration, and reaction temperature conditions as in Example 1 except that step (i) in Example 1 is omitted.

  In a 1 liter autoclave with a stirrer made of SUS316, 28.1 g of a 48 wt% aqueous sodium hydrosulfide solution (0.240 mol of sodium hydrosulfide) and 21.0 g of a 48 wt% aqueous sodium hydroxide solution (0.252 mol of sodium hydroxide) ), 36.0 g (0.245 mol) of p-dichlorobenzene (p-DCB) and 615.1 g (6.21 mol) of N-methyl-2-pyrrolidone (NMP) were charged. The amount of water contained in the raw material was 25.5 g (1.42 mol), and the amount of water per mol of the sulfur component of the sulfidizing agent was 5.92 mol. The amount of solvent per mole of sulfur component of the sulfiding agent was 2.50 L.

  The reactor was purged with nitrogen at room temperature, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating was started, the internal pressure gradually increased, and the gauge pressure reached 1.12 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as a sulfidizing agent was 96.6%, and the sulfidizing agent in the reaction mixture was all The formation rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 15.5%.

  Thus, in the case where cyclic PAS was produced under the conditions where the amount of water in the reaction mixture was large without performing step (i), the yield of cyclic PAS was equivalent to that in Example 1. It can be seen that the pressure in the reactor during heating greatly increases as the amount of water increases. Furthermore, the reaction product obtained in this comparative example contained a large amount of black component, and the liquid contact part of the reactor after the reaction product was recovered was also blackened and no metallic luster was observed.

[Example 2]
Here, an example in which the amount of water after step (i) is reduced as compared with Example 1 is shown.

<Process (i)>
The raw materials were charged in the same manner as in Example 1, heated from room temperature to 180 ° C. with stirring through nitrogen at normal pressure, and maintained at 180 ° C. for a while to obtain 33.6 g of a dehydrated distillate. Thereafter, the heating was stopped and the mixture was cooled to 130 ° C. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 5.4 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 14.2 g (0.791 mol). )Met. Further, from the result of ion chromatography, it was found that the sulfur component scattered as hydrogen sulfide during the dehydration step was 0.0013 mol, and as a result, the sulfur component remaining in the system was 0.399 mol. I understood it. Therefore, the water content in the system was found to be 1.98 mol per mol of sulfur component.

<Process (ii)>
Open the raw material inlet of the autoclave where step (i) was performed, and add 59.8 g (0.407 mol) of p-dichlorobenzene (p-DCB) and 947 g (0.923 liters) of NMP to the reaction system. The amount of NMP per mole of sulfur component was adjusted to 2.50 liters. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure was 0.49 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 97.5%, and all the sulfidizing agents in the reaction mixture were The formation rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 15.8%.
Further, only the step (i) of Example 2 was carried out separately, and uniformity determination and solidification temperature measurement were performed on the sulfidizing agent mixture recovered after cooling to room temperature. As a result, the solidification temperature was 120 ° C. In the above, it was confirmed that no sedimentation of solid content was observed. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 120 ° C. or higher.

  Thus, when the amount of water after step (i) is in the more preferred range of the present invention than in Example 1, cyclic polyarylene sulfide can be obtained in high yield, and the raw material consumption rate is high. High raw material loss hardly occurred.

[Example 3]
Here, after performing the step (i), an organic polar solvent is added to the reactor in which the step (i) has been performed so that the amount is 0.4 liter or more per mole of the sulfur component of the sulfidizing agent. An example is shown in which step (ii) is performed after the mixture is diluted and further divided and transferred to a reactor different from step (i).

<Process (i)>
In the same manner as in Example 2, a sulfidizing agent mixture having a water content of 1.96 mol per mol of the sulfur component of the sulfiding agent was obtained. Subsequently, 415 g of NMP was added while maintaining the internal temperature at 130 ° C., and dilution was performed in an autoclave so that the organic polar solvent was 1.20 liters per mole of sulfur component. By this operation, a low viscosity sulfidizing agent mixture was obtained. This was cooled to room temperature, collected in a stainless steel container, and weighed 541 g. The recovery rate for the theoretical yield of 544 g calculated from the amount of distillate was 99.4%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 270 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.199 mol, 0.209 mol as sodium hydroxide, and 0.239 liter as NMP). Thereto, 30.8 g (0.209 mol) of p-dichlorobenzene (p-DCB) and 266 g (0.259 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 2.50 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure reached 0.48 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 98.2%, and all the sulfidizing agents in the reaction mixture were all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 16.1%.
Further, only the step (i) of this Example 3 was carried out separately, and the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to uniformity judgment and solidification temperature measurement. It was confirmed that no sedimentation was observed at 120 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 120 ° C. or higher.

  Thus, after performing step (i), an organic polar solvent was added to the reactor in which step (i) was performed so that the amount was 0.4 liter or more per mole of sulfur component of the sulfidizing agent to sulfidize. When the step (ii) is carried out after the agent mixture is diluted and further transferred to a reactor different from step (i), the low internal pressure during reaction and the high raw material consumption rate are compatible as in Example 2. The cyclic polyarylene sulfide could be obtained with good yield.

[Reference Example 1]
Here, an example is shown in which the reaction product obtained in Example 3 is solid-liquid separated to recover the by-produced linear polyphenylene sulfide as a solid containing an organic polar solvent.

  120 g of the reaction product obtained in Example 3 was collected and charged into a 300 mL flask. The reaction product was stirred with a magnetic stirrer and heated to 100 ° C. in an oil bath while nitrogen bubbling was performed on the reaction product slurry.

  A PTFE membrane filter with a diameter of 90 mm and an average pore diameter of 1 μm is set in the ADVANTEC filter holder KST-90-UH (effective filtration area approximately 45 parallel centimeters) made by ADVANTEC, and the tank part is used as a band heater. The temperature was adjusted to 100 ° C.

  The reaction product heated to 100 ° C. was charged into a tank, the tank was sealed, and then pressurized to 0.4 MPa with nitrogen. Subsequently, the valve at the bottom of the tank was slowly opened to start filtration. When the filtrate was discharged, the operation was terminated, the tank was opened, and 62.5 g of a cake made of linear polyphenylene sulfide, NMP, and sodium chloride remaining on the membrane filter was recovered.

  4 g of the cake was weighed and dispersed in 40 g of water, stirred at 70 ° C. for 15 minutes, and then filtered with suction through a glass filter to remove NMP and sodium chloride in the cake. This washing operation was repeated a total of 4 times. The obtained solid content was dried by treating at 70 ° C. for 3 hours in a vacuum dryer, and the content of linear polyphenylene sulfide was calculated as a ratio to the weight of the cake weighed first, and found to be 21.3% by weight. When other components in the cake were analyzed by a drying method, NMP was 48.7% by weight and sodium chloride was 30.0% by weight. In addition, when the molecular weight of the obtained linear polyphenylene sulfide was measured by GPC, it was Mw = 12,000.

[Example 4]
Here, a synthesis example of cyclic polyphenylene sulfide in which the linear polyphenylene sulfide recovered in Reference Example 1 is included in the reaction mixture to recycle the linear polyphenylene sulfide as a raw material will be described.

  A SUS316 autoclave equipped with a stirrer was replaced with nitrogen, and 33.8 g of the sulfidizing agent mixture obtained in step (i) of Example 3 (0.0249 mol as a sulfur component, as sodium hydroxide) 0.0262 mol, 0.0299 liters as NMP). Thereto, 4.58 g (0.0311 mol) of p-dichlorobenzene (p-DCB), 50.6 g of the cake component obtained in Reference Example 1 (0.0997 mol as linear polyphenylene sulfide, 24.6 g as NMP) (0.0240 liters), 15.2 g as sodium chloride) and 289 g (0.282 liters) of NMP were added to adjust the amount of NMP per mole of sulfur component in the reaction mixture to 2.50 liters. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating was started, the internal pressure gradually increased, and at the end of the reaction, the gauge pressure became 0.34 MPa. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  In addition, the reaction product obtained was analyzed by high performance liquid chromatography and ion chromatography in consideration of the fact that the added linear PAS was also used as a raw material, and as a result, all sulfur components in the reaction mixture were used as a reference. The raw material consumption rate of sodium hydrosulfide was 98.0%, and the production rate of cyclic polyphenylene sulfide was 12.2% when all sulfur components in the reaction mixture were assumed to be converted to cyclic polyphenylene sulfide.

  Thus, when linear polyphenylene sulfide is contained in the reaction mixture before performing step (ii), the yield of cyclic polyphenylene sulfide is reduced as compared with Examples 1, 2, and 3. It was found that the linear polyphenylene sulfide produced as a by-product in Example 3 can be effectively used as a raw material, and that it is effective for saving raw materials such as sodium hydrosulfide and dichlorobenzene. Moreover, the low internal pressure at the time of reaction and the high raw material consumption rate were able to be made compatible.

[Comparative Example 2]
Here, in comparison with Example 3, an example is shown in which water is dehydrated to less than 0.8 mole per mole of sulfur component of the sulfidizing agent in step (i).

<Process (i)>
The raw materials were charged in the same manner as in Example 1 and heated from room temperature to 210 ° C. with stirring through nitrogen at normal pressure. When 60.7 g of dehydrated distillate was obtained, the heating was stopped and cooled to 130 ° C. . Then, since the contents solidified and stirring was stopped, the internal temperature was reheated to 150 ° C. to maintain the liquid state. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 22.0 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 3.8 g (0.209 mol). )Met. Also, the results of ion chromatography analysis show that the sulfur component scattered as hydrogen sulfide during the dehydration process is 0.0036 mol, and as a result, the sulfur component remaining in the system is 0.396 mol. I found out. Therefore, it was found that the water content in the system was 0.53 mol per mol of sulfur component.

  Subsequently, 428 g of NMP was added to the autoclave while maintaining the internal temperature at 150 ° C., and the organic polar solvent was diluted to 1.20 liter per mole of sulfur component. By this operation, a low viscosity sulfidizing agent mixture was obtained. This was cooled to room temperature, collected in a stainless steel container and weighed to be 527 g. The recovery rate for the theoretical yield of 531 g calculated from the amount of the distillate was 99.3%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 264 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.198 mol, 0.208 mol as sodium hydroxide, and 0.238 liter as NMP). Add 30.6 g (0.208 mol) of p-dichlorobenzene (p-DCB) and 264 g (0.258 liter) of NMP to adjust the amount of NMP per mol of sulfur component in the reaction system to 2.50 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating was started, the internal pressure gradually increased, and at the end of the reaction, the gauge pressure became 0.38 MPa. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as a sulfidizing agent was 93.0%, and all the sulfidizing agents in the reaction mixture were The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 15.0%.
Further, only the step (i) of this Comparative Example 2 was separately carried out, and when the uniformity determination and the solidification temperature measurement were performed on the sulfidizing agent mixture recovered after cooling to room temperature without dilution, the solidification temperature was 140 ° C. It was confirmed that no sedimentation was observed at 140 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 140 ° C. or higher.

  Thus, when water is dehydrated to less than 0.8 mole per mole of sulfur component of the sulfidizing agent in step (i), the yield of cyclic polyphenylene sulfide is not significantly different from the results of Examples 1, 2, and 3. However, the raw material consumption rate was clearly reduced. This leads to problems such as raw material loss and quality deterioration of the target product due to unreacted raw material contamination. Moreover, it turned out that the solidification temperature of the obtained sulfidizing agent mixture becomes comparatively high, and high temperature is required when it is necessary to maintain a liquid state.

[Example 5]
Here, an example in which the amount of the organic polar solvent in the step (i) is increased as compared with the case of Example 3 is shown.

<Process (i)>
A distillation tower was attached to the top of an autoclave with a stirrer made of SUS316, and a cooling pipe and a container for receiving condensate were installed at the top. In an autoclave, 46.7 g of a 48 wt% sodium hydrosulfide aqueous solution (0.400 mol as sodium hydrosulfide), 35.0 g of a 48 wt% sodium hydroxide aqueous solution (0.420 mol as sodium hydroxide), N-methyl 2-pyrrolidone (NMP) 160g (0.156 liter) was charged. The amount of water contained in the raw material was 42.5 g (2.36 mol), and the amount of water per mol of the sulfur component of the sulfidizing agent was 5.90 mol. The amount of organic polar solvent per mole of sulfur component of the sulfidizing agent was 0.390 liters.

  While stirring at normal pressure through nitrogen, the mixture was heated from room temperature to 180 ° C. and maintained at 180 ° C. for a while to obtain 35.6 g of a dehydrated distillate. Thereafter, the heating was stopped and the mixture was cooled to 130 ° C. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 8.1 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 15.0 g (0.833 mol). )Met. Further, the results of ion chromatography analysis show that the sulfur component scattered as hydrogen sulfide during the dehydration process is 0.0012 mol, and as a result, the sulfur component remaining in the system is 0.399 mol. I found out. Therefore, the water content in the system was found to be 2.09 mol per mol of sulfur component.

  Subsequently, 339 g of NMP was added to the autoclave while maintaining the internal temperature at 130 ° C., and the organic polar solvent was diluted to 1.20 liter per mole of sulfur component. By this operation, a low-viscosity sulfidizing agent mixture was obtained, but it was confirmed that 0.1 g of red solid having a particle diameter of about 3 to 5 mm was precipitated at the bottom of the container.

  The contents were cooled to room temperature, recovered in a stainless steel container and weighed to be 540 g. The recovery rate for the theoretical yield of 545 g calculated from the amount of the distillate was 99.0%. Qualitative analysis of the red solid content revealed that it was a compound containing ionic sulfur, and the recovery rate of the sulfur component in the sulfidizing agent mixture was calculated to be 98.7%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 270 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.199 mol, 0.209 mol as sodium hydroxide, and 0.239 liter as NMP). Thereto, 30.8 g (0.209 mol) of p-dichlorobenzene (p-DCB) and 266 g (0.259 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 2.50 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure reached 0.48 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 97.5%, and all the sulfidizing agents in the reaction mixture were The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 15.3%.

  Further, only the step (i) of this Example 5 was carried out separately, and the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to uniformity judgment and solidification temperature measurement. It was confirmed that a slight sedimentation of solids having a particle size of about 3 to 5 mm was observed at 120 ° C. or higher. Therefore, this sulfidizing agent mixture was not uniform.

  Thus, in the example in which the amount of the organic polar solvent in step (i) was increased from that in Example 3, a small amount of red solid containing sulfur was produced in step (i), but the amount was slight. As long as it is within the preferred range of the present invention, the influence on the raw material molar balance was slight, and the yield of cyclic polyphenylene sulfide was the same as in Examples 1, 2, and 3. Moreover, the raw material consumption rate was high, and almost no raw material loss occurred.

[Comparative Example 3]
Here, in comparison with Example 3, an example is shown in which dehydration is performed in the step (i) under the condition that the amount of the organic polar solvent is 0.4 liter or more per mole of the sulfur component of the sulfidizing agent.

<Process (i)>
A distillation tower was attached to the top of an autoclave with a stirrer made of SUS316, and a cooling pipe and a container for receiving condensate were installed at the top. In an autoclave, 46.7 g of a 48 wt% sodium hydrosulfide aqueous solution (0.400 mol as sodium hydrosulfide), 35.0 g of a 48 wt% sodium hydroxide aqueous solution (0.420 mol as sodium hydroxide), N-methyl 2-pyrrolidone (NMP) 410 g (0.400 liter) was charged. The amount of water contained in the raw material was 42.5 g (2.36 mol), and the amount of water per mol of the sulfur component of the sulfidizing agent was 5.90 mol. The amount of organic polar solvent per mole of sulfur component of the sulfiding agent was 1.00 liter.

  The mixture was heated from room temperature to 180 ° C. while stirring through nitrogen at normal pressure and maintained at 180 ° C. for a while to obtain 39.7 g of a dehydrated distillate. Thereafter, the heating was stopped and the mixture was cooled to 130 ° C. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 13.0 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 15.7 g (0.874 mol). )Met. Further, the results of ion chromatography analysis show that the sulfur component scattered as hydrogen sulfide during the dehydration process is 0.0012 mol, and as a result, the sulfur component remaining in the system is 0.399 mol. I found out. Therefore, the water content in the system was found to be 2.19 mol per mol of sulfur component.

  Subsequently, 94 g of NMP was added to the autoclave while maintaining the internal temperature at 130 ° C., and the organic polar solvent was diluted to 1.20 liter per mole of sulfur component. By this operation, a low-viscosity sulfidizing agent mixture was obtained, and it was confirmed that 7.1 g of a red solid having a particle size of about 3 to 10 mm was precipitated on the bottom of the container. The contents were cooled to room temperature, recovered in a stainless steel container and weighed to be 534 g. The recovery rate with respect to the theoretical yield of 546 g calculated from the amount of the distillate was 97.8%. Qualitative analysis of the red solid content revealed that it was a compound containing ionic sulfur, and the sulfur component recovery rate in the sulfidizing agent mixture was calculated to be 75.3%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously purged with nitrogen, and the sulfidizing agent mixture obtained in the step (i) was 267 g in a half amount. Was charged. (According to the proportional calculation, the amount of the charged sulfur component is 0.200 mol, the amount of sodium hydroxide is 0.210 mol, and the amount of NMP is 0.240 liters.) P-dichlorobenzene (p-DCB) 30.8 g (0.209 mol) and 266 g (0.259 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 2.50 liter. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure reached 0.48 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature and the reaction product was recovered. The reaction solution was an emulsion. This is presumably because a large amount of red solid was precipitated in step (i), so that the mixture of the sulfidizing agent became non-uniform and could not be accurately divided and could not be reacted with the assumed raw material composition.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 98.1%, and the sulfidizing agent in the reaction mixture was all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 10.0%.

  Further, only the step (i) of this Comparative Example 3 was carried out separately, and the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to homogeneity judgment and solidification temperature measurement. It was confirmed that a large amount of solids had settled at 120 ° C. or higher. Therefore, this sulfidizing agent mixture was heterogeneous.

  Thus, when the organic polar solvent is dehydrated in the step (i) under the condition of 0.4 liter or more per mole of the sulfur component of the sulfidizing agent, a large amount of red solid containing sulfur is precipitated at the end of the step (i). I understood it. This makes it difficult to accurately split the sulfidizing agent mixture, and this has caused a shift in the molar balance in step (ii), so that the yield of cyclic polyphenylene sulfide is as in Examples 1, 2, and 3. It is thought that it has greatly decreased compared to the case.

[Comparative Example 4]
Here, in comparison with Example 3, an example in which the amount of water after performing step (i) is more than 6.0 moles per mole of sulfur component of the sulfidizing agent is shown.

<Process (i)>
A distillation tower was attached to the top of an autoclave with a stirrer made of SUS316, and a cooling pipe and a container for receiving condensate were installed at the top. In an autoclave, 46.7 g of a 48 wt% sodium hydrosulfide aqueous solution (0.400 mol as sodium hydrosulfide), 35.0 g of a 48 wt% sodium hydroxide aqueous solution (0.420 mol as sodium hydroxide), N-methyl 2-Pyrrolidone (NMP) 82.0 g (0.0799 liter) and water 40.0 g were charged. The amount of water contained in the raw material was 82.5 g (4.58 mol), and the amount of water per 1 mol of the sulfur component of the sulfidizing agent was 11.46 mol. The amount of the organic polar solvent per mole of sulfur component of the sulfiding agent was 0.200 liter.

  The mixture was heated from room temperature to 180 ° C. with stirring through nitrogen at normal pressure, and maintained at 180 ° C. for a while to obtain 38.5 g of dehydrated distillate. Thereafter, heating was stopped and the mixture was cooled to 130 ° C. Here, when the dehydrated distillate was analyzed by gas chromatography, it contained 2.9 g of NMP component. Based on this information, the amount of water remaining in the system was calculated to be 46.9 g (2.60 mol). )Met. Also, the results of ion chromatography analysis show that the sulfur component scattered as hydrogen sulfide during the dehydration process is 0.0008 mol, so that the sulfur component remaining in the system is 0.399 mol. I found out. Therefore, it was found that the water content in the system was 6.52 mol per mol of sulfur component.

  Subsequently, 412 g of NMP was added to the autoclave while maintaining the internal temperature at 130 ° C., and the organic polar solvent was diluted to 1.20 liter per mole of sulfur component. By this operation, a low viscosity sulfidizing agent mixture was obtained. This was recovered in a stainless steel container and weighed 572 g. The recovery rate with respect to the theoretical yield of 577 g calculated from the amount of the distillate was 99.0%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously purged with nitrogen, and 286 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.200 mol, 0.210 mol as sodium hydroxide, and 0.241 liter as NMP). Thereto, 30.8 g (0.210 mol) of p-dichlorobenzene (p-DCB) and 266 g (0.259 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 2.50 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure was 0.87 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 97.8%, and the sulfidizing agent in the reaction mixture was all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 16.0%.

  As described above, when the cyclic polyphenylene sulfide was produced under the condition that the step (i) was not carried out and the water content in the reaction mixture was large, the yield of the cyclic polyphenylene sulfide was as described in Examples 1, 2, However, it was found that a reactor having a high pressure resistance is required because the pressure during the reaction is 0.87 MPa, which is much larger than that of the example. In addition, the inner wall of the autoclave (made of SUS) after completion of the reaction had evidence of corrosion (blackening) that was not confirmed in the examples, and it was also confirmed that the black matter was partially mixed in the reaction solution. .

[Example 6]
Here, an example in which the amount of the organic polar solvent in the step (ii) is increased as compared with the case of Example 3 is shown.

<Process (i)>
By the same operation as in Example 3, 542 g of a sulfidizing agent mixture having a water content of 1.96 mol per mol of the sulfur component of the sulfiding agent was obtained. The recovery based on the theoretical yield of 544 g was 99.6%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 271 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.199 mol, 0.209 mol as sodium hydroxide, and 0.239 liter as NMP). Thereto, 30.8 g (0.209 mol) of p-dichlorobenzene (p-DCB) and 437 g (0.426 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 3.33 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and at the end of the reaction, the gauge pressure became 0.44 MPa. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as a sulfidizing agent was 96.6%, and the sulfidizing agent in the reaction mixture was all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 23.3%.

  Further, only the step (i) of Example 6 was carried out separately, and the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to uniformity judgment and measurement of the solidification temperature. It was confirmed that no sedimentation was observed at 120 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 120 ° C. or higher.

  Thus, in the example where the amount of the organic polar solvent in the step (ii) is increased as compared with the case of Example 3, it is possible to achieve both a low internal pressure during the reaction and a high raw material consumption rate, and the cyclic polyarylene with high yield. Sulfide could be obtained.

[Comparative Example 5]
Here, in comparison with Example 6, an example is shown in which water is dehydrated to less than 0.8 mole per mole of sulfur component of the sulfidizing agent in step (i).

<Process (i)>
By the same operation as in Comparative Example 2, 525 g of a sulfidizing agent mixture having a water content of 0.53 mol per 1 mol of the sulfur component of the sulfiding agent was obtained. The recovery based on the theoretical yield of 531 g was 98.9%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously purged with nitrogen, and 263 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.198 mol, 0.208 mol as sodium hydroxide, and 0.238 liter as NMP). Thereto, 30.6 g (0.208 mol) of p-dichlorobenzene (p-DCB) and 436 g (0.425 liter) of NMP were added to adjust the amount of NMP per mol of sulfur component in the reaction system to 3.33 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating was started, the internal pressure gradually increased, and at the end of the reaction, the gauge pressure became 0.34 MPa. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 89.5%, and all the sulfidizing agents in the reaction mixture were The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 22.8%.

  Further, only the step (i) of this Comparative Example 5 was separately carried out, and when the uniformity of the sulfidizing agent mixture recovered after cooling to room temperature without dilution was measured and the solidification temperature was measured, the solidification temperature was 140 ° C. It was confirmed that no sedimentation was observed at 140 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 140 ° C. or higher.

  Thus, when water is dehydrated to less than 0.8 mole per mole of sulfur component of the sulfiding agent in step (i), the yield of cyclic polyphenylene sulfide is almost the same as the result of Example 6. However, the raw material consumption rate was significantly lower than that in Example 6. From this result, under conditions where the substrate concentration in the step (ii) as shown in Example 6 and Comparative Example 5 is relatively low, the raw material consumption rate is extremely reduced by reducing the amount of water in the step (i), It was found that this is a concentration region where the effect of the present invention is more conspicuous.

[Example 7]
Here, an example in which the amount of the organic polar solvent in the step (ii) is reduced as compared with the case of Example 3 is shown.

<Process (i)>
By the same operation as in Example 3, 541 g of a sulfidizing agent mixture having a water content of 1.96 mol per mol of the sulfur component of the sulfiding agent was obtained. The recovery based on the theoretical yield of 544 g was 99.4%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 270 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.199 mol, 0.209 mol as sodium hydroxide, and 0.239 liter as NMP). 30.8 g (0.209 mol) of p-dichlorobenzene (p-DCB) and 97 g (0.0945 liter) of NMP were added thereto, and the amount of NMP per mol of sulfur component in the reaction system was adjusted to 1.67 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and the gauge pressure reached 0.58 MPa at the end of the reaction. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as the sulfidizing agent was 98.0%, and all the sulfidizing agents in the reaction mixture were all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 11.8%.

  Further, only the step (i) of Example 7 was carried out separately, and when the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to uniformity judgment and solidification temperature measurement, the solidification temperature was set to 120 ° C. It was confirmed that no sedimentation was observed at 120 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 120 ° C. or higher.

  Thus, in the example in which the amount of the organic polar solvent in the step (ii) is reduced as compared with the case of Example 3, the yield of the cyclic polyphenylene sulfide is slightly reduced, but the low internal pressure and the high raw material consumption rate during the reaction are reduced. I was able to achieve both.

[Example 8]
Here, an example in which the amount of the organic polar solvent in step (ii) is further reduced than in the case of Example 7 will be described.

<Process (i)>
By the same operation as in Example 3, 541 g of a sulfidizing agent mixture having a water content of 1.96 mol per mol of the sulfur component of the sulfiding agent was obtained. The recovery based on the theoretical yield of 544 g was 99.4%.

<Process (ii)>
A SUS316 autoclave equipped with a stirrer (different from that used in the step (i)) was previously substituted with nitrogen, and 270 g (sulfur component) of the sulfidizing agent mixture obtained in the step (i) was obtained. As 0.199 mol, 0.209 mol as sodium hydroxide, and 0.239 liter as NMP). Thereto, 30.8 g (0.209 mol) of p-dichlorobenzene (p-DCB) and 12 g (0.0114 liter) of NMP were added, and the amount of NMP per mol of sulfur component in the reaction system was adjusted to 1.25 liter. did. Subsequently, the reactor was purged with nitrogen, sealed, heated from room temperature to 200 ° C. over 25 minutes with stirring at 400 rpm, and then heated from 200 ° C. to 250 ° C. over 35 minutes. Then, the reaction mixture was heated and reacted by maintaining at 250 ° C. for 2 hours. When heating started, the internal pressure gradually increased, and at the end of the reaction, the gauge pressure became 0.68 MPa. After completion of the reaction, the autoclave was cooled to near room temperature, and the reaction product was recovered.

<Reaction product analysis evaluation>
A part of the obtained reaction product was dispersed in a large excess of water to recover components insoluble in water, and then dried to obtain a solid content. As a result of structural analysis by infrared spectroscopic analysis, it was confirmed that the solid content was a compound composed of phenylene sulfide units.

  Moreover, as a result of analyzing the obtained reaction product by high performance liquid chromatography and ion chromatography, the raw material consumption rate of sodium hydrosulfide used as a sulfidizing agent was 98.3%, and all the sulfidizing agents in the reaction mixture were all The production rate of cyclic polyphenylene sulfide when converted to cyclic polyphenylene sulfide was 10.3%.

  Further, only the step (i) of Example 8 was carried out separately, and the sulfidizing agent mixture recovered after cooling to room temperature without dilution was subjected to uniformity judgment and solidification temperature measurement. The solidification temperature was 120 ° C. It was confirmed that no sedimentation was observed at 120 ° C. or higher. Therefore, it was found that this sulfidizing agent mixture was uniform and exhibited high transportability at 120 ° C. or higher.

  Thus, in the example where the amount of the organic polar solvent in the step (ii) is further reduced than in the case of Example 7, although the yield of the cyclic polyphenylene sulfide is lowered, the low internal pressure and the high raw material consumption rate during the reaction are reduced. I was able to achieve both.

Claims (11)

A method for producing a cyclic polyarylene sulfide by heating a reaction mixture containing at least a sulfidizing agent, a dihalogenated aromatic compound and an organic polar solvent, comprising at least the following steps (i) and (ii): A process for producing a cyclic polyarylene sulfide, characterized in that
(I) at least sulfidizing agent, a mixture comprising an organic polar solvent and water, a mixture comprising an organic polar solvent under 0.4 liters sulfur contained 1 mole per 0.1 liters or more of the sulfidizing agent 0.99 ° C. or higher Heating at 250 ° C. or lower, and preparing a sulfidizing agent mixture having a water content of 0.8 mol or more and 6.0 mol or less per mol of sulfur component of the sulfidizing agent, at least after step (i) The reaction mixture containing the sulfidizing agent mixture obtained in step (i), the dihalogenated aromatic compound and the organic polar solvent is 1.25 liters to 50 liters per mole of the sulfur component in the reaction mixture. Heating under the conditions The method for producing a cyclic polyarylene sulfide according to claim 1, wherein the mixture of the sulfidizing agent obtained in step (i) is uniform. In step (i), a mixture containing an organic polar solvent of 0.1 liter or more and less than 0.4 liter per mole of the sulfur component of the sulfidizing agent is heated, and the water content is reduced to 0. The method for producing a cyclic polyarylene sulfide according to claim 1, wherein a mixture of 8 mol to 3.0 mol of a sulfidizing agent is prepared. In step (i), a mixture containing more than 3.0 moles of water per mole of sulfur component of the sulfiding agent is heated to dehydrate, and the amount of water is 0.8 moles or more per mole of sulfur component of the sulfiding agent. The method for producing a cyclic polyarylene sulfide according to claim 3, wherein a mixture of the sulfiding agent reduced to 0.0 mol or less is obtained. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 4, wherein the steps (i) and (ii) are carried out in separate reactors. In the reactor in which step (i) is performed after step (i), the organic polar solvent is added to the sulfidizing agent mixture and diluted so that the organic polar solvent is 0.4 liter or more per mole of sulfur component. A process for producing a cyclic polyarylene sulfide according to any one of claims 1 to 5. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 6, wherein in step (ii), the reaction mixture is heated beyond the reflux temperature at normal pressure. The method for producing cyclic polyarylene sulfide according to any one of claims 1 to 7, wherein the pressure in step (ii) is 0.8 MPa or less in terms of gauge pressure. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 8, wherein the sulfiding agent is an alkali metal sulfide. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 9, wherein the dihalogenated aromatic compound is dichlorobenzene. The method for producing a cyclic polyarylene sulfide according to any one of claims 1 to 10, wherein linear polyarylene sulfide is contained in the reaction mixture before performing step (ii).