JP5888143B2 - Method for producing aqueous solution containing alkali metal-containing inorganic salt and method for producing composition containing carboxyalkylamino group-containing compound and polyhaloaromatic compound - Google Patents

Description

  The present invention relates to a method for producing an aqueous solution having a low COD (Chemical Oxygen Demand) value containing an alkali metal-containing inorganic salt and a method for producing a carboxyalkylamino group-containing compound. More specifically, from the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound that is a COD-causing substance, the alkali metal-containing inorganic is used as waste water after purification in the production process of the polyarylene sulfide resin. The present invention relates to a method for producing an aqueous solution having a low COD value containing an alkali metal-containing inorganic salt and a method for producing a carboxyalkylamino group-containing compound by separating an aqueous solution containing a salt and a carboxyalkylamino group-containing compound.

  A polyarylene sulfide resin (PAS resin) typified by a polyphenylene sulfide resin is excellent in heat resistance and chemical resistance, and is widely used for electrical and electronic parts, automobile parts, water heater parts, fibers, films and the like. In particular, in applications such as packing for lithium ion batteries and gasket members, in recent years, high molecular weight polyarylene sulfide resins have been widely used because of their excellent toughness and moldability.

  The polyarylene sulfide resin is obtained by a method of polymerizing a sulfidizing agent and a polyhaloaromatic compound in an organic polar solvent such as N-methyl-2-pyrrolidone (hereinafter sometimes abbreviated as NMP). Together with the target polyarylene sulfide resin, a solvent, an alkali metal-containing inorganic salt such as sodium chloride, and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物などの有機塩といった副生成物を含有する粗反応生成物が得られる。重合反応後の粗反応生成物は適当な容器に取り出され、粗反応生成物中の溶媒は溶媒乾燥装置、濾過器、遠心分離器等の適当な固液分離装置を用いて脱溶媒処理により分離回収される（本操作を脱溶媒という）。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.) A crude reaction product containing a by-product such as an organic salt such as a carboxyalkylamino group-containing compound Things are obtained. The crude reaction product after the polymerization reaction is taken out into an appropriate container, and the solvent in the crude reaction product is separated by solvent removal using an appropriate solid-liquid separation device such as a solvent drying device, a filter, or a centrifuge. It is recovered (this operation is called desolvation).

  Furthermore, since the reaction product obtained after the desolvation treatment contains by-products such as the organic metal salt such as the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound together with the target polyarylene sulfide resin, Filtration is repeated to remove these by-products. In general, there are a water washing method performed at less than 100 ° C. and a hot water washing performed at a high temperature and high pressure of 100 ° C. or higher. The polyarylene sulfide obtained after washing with water or hot water is separated with a filter, a centrifugal filter or the like, then dried, and subjected to a heat treatment as necessary to obtain a product.

  On the other hand, wastewater obtained after washing with water or hot water has been treated as industrial waste and has not been effectively utilized. However, since organic salts such as carboxyalkylamino group-containing compounds contained in these wastewaters cause COD loading, it has been required to reduce COD substances in order to reduce environmental burden.

  However, the wastewater also contains an alkali metal-containing inorganic salt such as sodium chloride, and it was difficult to separate the alkali metal-containing inorganic salt from the carboxyalkylamino group-containing compound.

  As a treatment method for reducing COD substances in wastewater, for example, an acid flocculant is added to wastewater to adjust pH, so that COD substances are insolubilized, and insolubilized COD substances are separated. Etc. are known (see Patent Document 1). However, in this method, the waste water of the purification process is introduced, the mixing function is provided, and the aggregation reaction tank equipped with the pH indicating controller and capable of pH adjustment and aggregation treatment is introduced from the aggregation reaction tank. Since it is a method of separation using a continuous centrifugal separator that separates insolubilized COD material, the water content of the separated COD material becomes high and bulky, and handling becomes complicated, and the separated COD material is separated from industrial waste. Therefore, it was not preferable.

  On the other hand, the present inventors have the following structural formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物が、線状高分子量ＰＡＳ樹脂の熱酸化架橋剤として作用するだけでなく、かつ、溶融時の増粘を抑えて樹脂の溶融安定性を向上させるとともに、成形固化時の結晶化速度の速い架橋型ポリアリーレンスルフィド樹脂およびその製造方法を提供できることを明らかにした（特願２０１２−０２０８４６号）。このため、前記カルボキシアルキルアミノ基含有化合物を高純度で製造する方法が求められていた。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X represents a hydrogen atom or an alkali metal atom.) A carboxyalkylamino group-containing compound represented by the following formula is used as a thermal oxidation cross-linking agent for a linear high molecular weight PAS resin. It is clear that it is possible to provide a cross-linked polyarylene sulfide resin not only acting but also improving the melt stability of the resin by suppressing the thickening at the time of melting, and having a high crystallization speed at the time of molding and solidification, and a method for producing the same. (Japanese Patent Application No. 2012-020846). For this reason, a method for producing the carboxyalkylamino group-containing compound with high purity has been demanded.

JP 2003-275773 A

  Therefore, the problem to be solved by the present invention is to efficiently separate an aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound from an aqueous solution containing an alkali metal-containing inorganic salt and a carboxyalkylamino group-containing compound. , As an aqueous solution containing an alkali metal-containing inorganic salt or as the carboxyalkylamino group-containing compound, respectively, in particular, an alkali metal-containing inorganic salt and a carboxy obtained as waste water after purification in the production process of polyarylene sulfide resin An aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound are efficiently separated from an aqueous solution containing an alkylamino group-containing compound, and as an aqueous solution containing an alkali metal-containing inorganic salt, or containing the carboxyalkylamino group Conversion As things, is to provide a method for obtaining respectively, the.

As a result of various investigations, the inventors of the present application modified the terminal of the carboxyalkylamino group-containing compound into a carboxylic acid by acidic treatment of an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound, It has been found that by adding a polyhaloaromatic compound, a carboxyalkylamino group-containing compound can be separated from an aqueous solution containing an alkali metal-containing inorganic salt, and the present invention has been completed.
That is, the present invention relates to an alkali metal-containing inorganic salt and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液から、アルカリ金属含有無機塩を含む水溶液と前記カルボキシアルキルアミノ基含有化合物とを分離して、前記カルボキシアルキルアミノ基含有化合物を製造する方法であって、
（１）前記水溶液をｐＨ６．０以下に調整する工程１、
（２）前記水溶液にポリハロ芳香族化合物を加えて、前記カルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む有機相と、アルカリ金属含有無機塩を含む水相に分離する工程２、
（３）分離したカルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む有機相を除去して、アルカリ金属含有無機塩を含む水溶液を回収する工程３、
を有することを特徴とするアルカリ金属含有無機塩を含む水溶液の製造方法に関する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom), and an aqueous solution containing an alkali metal-containing inorganic salt; A method for producing the carboxyalkylamino group-containing compound by separating the carboxyalkylamino group-containing compound,
(1) Step 1 of adjusting the aqueous solution to pH 6.0 or less,
(2) Step 2, in which a polyhaloaromatic compound is added to the aqueous solution and separated into an organic phase containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound and an aqueous phase containing an alkali metal-containing inorganic salt,
(3) Step 3 of removing the organic phase containing the separated carboxyalkylamino group-containing compound and polyhaloaromatic compound to recover an aqueous solution containing an alkali metal-containing inorganic salt;
The present invention relates to a method for producing an aqueous solution containing an alkali metal-containing inorganic salt.

  The present invention also relates to an alkali metal-containing inorganic salt and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液から、アルカリ金属含有無機塩を含む水溶液と前記カルボキシアルキルアミノ基含有化合物とを分離して、前記カルボキシアルキルアミノ基含有化合物を製造する方法であって、
（１）前記水溶液をｐＨ６．０以下に調整する工程１、
（２）前記水溶液にポリハロ芳香族化合物を加えて、前記カルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む有機相と、アルカリ金属含有無機塩を含む水相に分離する工程２、
（４）分離したアルカリ金属含有無機塩を含む水相を除去して、前記カルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む有機相を回収する工程４、を有することを特徴とするカルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む組成物の製造方法に関する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom), and an aqueous solution containing an alkali metal-containing inorganic salt; A method for producing the carboxyalkylamino group-containing compound by separating the carboxyalkylamino group-containing compound,
(1) Step 1 of adjusting the aqueous solution to pH 6.0 or less,
(2) Step 2, in which a polyhaloaromatic compound is added to the aqueous solution and separated into an organic phase containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound and an aqueous phase containing an alkali metal-containing inorganic salt,
(4) Step 4 of removing the aqueous phase containing the separated alkali metal-containing inorganic salt and recovering the organic phase containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound. The present invention relates to a method for producing a composition comprising an amino group-containing compound and a polyhaloaromatic compound.

  Furthermore, the present invention further includes adding an alkaline aqueous solution to the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained by the above-described production method, and the polyhaloaromatic compound and the following general formula ( 2)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘ’はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液と、に分離する工程５、続いて、
（６）分離したポリハロ芳香族化合物を除去して、該カルボキシアルキルアミノ基含有化合物を含む水溶液を回収する工程６、を有するカルボキシアルキルアミノ基含有化合物を含む水溶液の製造方法に関する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² represents an alkylene group having 3 to 5 carbon atoms, and X ′ represents an alkali metal atom.) And an aqueous solution containing a carboxyalkylamino group-containing compound represented by step 5;
(6) The present invention relates to a method for producing an aqueous solution containing a carboxyalkylamino group-containing compound, comprising removing a separated polyhaloaromatic compound and recovering an aqueous solution containing the carboxyalkylamino group-containing compound.

  Furthermore, in the present invention, an alkaline aqueous solution is further added to the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained by the production method described above, and the polyhaloaromatic compound and the following general formula ( 2)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘ’はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液とに分離する工程５、続いて、
（７）分離した該カルボキシアルキルアミノ基含有化合物を含む水溶液を除去して、ポリハロ芳香族化合物を回収する工程７、を有し、工程７で得られたポリハロ芳香族化合物を工程２で使用することを特徴とするアルカリ金属含有無機塩を含む水溶液またはカルボキシアルキルアミノ基含有化合物およびポリハロ芳香族化合物を含む組成物の製造方法に関する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; Step ² in which R ² is separated into an alkylene group having 3 to 5 carbon atoms, and X ′ represents an alkali metal atom, and an aqueous solution containing a carboxyalkylamino group-containing compound represented by:
(7) removing the aqueous solution containing the separated carboxyalkylamino group-containing compound and recovering the polyhaloaromatic compound, and using the polyhaloaromatic compound obtained in step 7 in step 2 The present invention relates to a method for producing an aqueous solution containing an alkali metal-containing inorganic salt or a composition containing a carboxyalkylamino group-containing compound and a polyhaloaromatic compound.

  According to the present invention, an aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound are efficiently separated from an aqueous solution containing an alkali metal-containing inorganic salt and a carboxyalkylamino group-containing compound. Methods for obtaining each as an aqueous solution containing a salt or as the carboxyalkylamino group-containing compound, in particular, an alkali metal-containing inorganic salt and a carboxyalkylamino group-containing compound obtained as waste water after purification in the production process of the polyarylene sulfide resin An aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound are efficiently separated from an aqueous solution containing an alkali metal-containing inorganic salt as an aqueous solution, or as the carboxyalkylamino group-containing compound, respectively. That way, it is possible to provide a.

(Process 1)
The present invention relates to an alkali metal-containing inorganic salt and the following general formula (1)

（式中、ｎは０〜２であり、Ｙ^１はハロゲン原子を、Ｙ^２は水素原子又はハロゲン原子を、Ｒ^１は水素原子又は炭素原子数１〜３のアルキル基又はシクロヘキシル基を表し、Ｒ^２は炭素原子数３〜５のアルキレン基を、Ｘは水素原子又はアルカリ金属原子を表す。）で表されるカルボキシアルキルアミノ基含有化合物を含む水溶液をｐＨ６．０以下に調整する工程１を有する。

Wherein n is 0 to 2, Y ¹ represents a halogen atom, Y ² represents a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom, an alkyl group having 1 to 3 carbon atoms, or a cyclohexyl group; R ² is an alkylene group having 3 to 5 carbon atoms, and X is a hydrogen atom or an alkali metal atom.) A step 1 of adjusting an aqueous solution containing a carboxyalkylamino group-containing compound represented by pH 1 to pH 6.0 or lower. Have.

  Here, the preparation of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound is at least an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound, The inorganic salt is contained in the range of 0.1 to 26% by mass and the carboxyalkylamino group-containing compound is contained in the range of 0.01 to 5% by mass and substantially free of polyarylene sulfide resin. Do. The preparation method of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound may be any method as long as the above composition can be prepared, but the water containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound may be used. What is necessary is just to adjust to pH 10.0-13.0 by adding an alkali and to melt | dissolve by heating in the range of 40-90 degreeC. Moreover, the aqueous solution containing the alkali metal containing inorganic salt obtained by the refinement | purification process of polyarylene sulfide resin polymerization and the said carboxyalkylamino group containing compound can also be used. However, the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound substantially does not contain a polyarylene sulfide resin, which basically means that it is below the detection limit, When adjusted in the purification process of the polyarylene sulfide resin, a very small amount of the polyarylene sulfide resin may be contained depending on the method and degree of the purification treatment, and the concentration of the polyarylene sulfide resin in the aqueous solution The sulfide resin concentration is 1 ppm or less, and even when it is large, it is 5 ppm or less.

  As a method of obtaining an aqueous solution containing an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound in the purification step of polyarylene sulfide resin polymerization, in a polar organic solvent, a polyhaloaromatic compound and (i) an alkali metal sulfide Or (ii) a crude containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound, and the organic polar solvent by reacting an alkali metal hydrosulfide and an alkali metal hydroxide. A reaction mixture is obtained (polymerization step), and then the organic polar solvent is solid-liquid separated from the crude reaction mixture to obtain a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt, and the carboxyalkylamino group-containing compound ( Solid-liquid separation step), and then contacting the reaction mixture with water to Through the step (purification step) filtering off the Lee sulfide resin may be a method of obtaining an aqueous solution containing an alkali metal-containing inorganic salt and said carboxyalkyl amino group-containing compound.

  Here, the polyhaloaromatic compound used in the polymerization process of the polyarylene sulfide resin is, for example, a halogenated aromatic compound having two or more halogen atoms directly bonded to the aromatic ring, and specifically, p-dichlorobenzene, o-dichlorobenzene, m-dichlorobenzene, trichlorobenzene, tetrachlorobenzene, dibromobenzene, diiodobenzene, tribromobenzene, dibromonaphthalene, triiodobenzene, dichlorodiphenylbenzene, Dihaloaromatics such as dibromodiphenylbenzene, dichlorobenzophenone, dibromobenzophenone, dichlorodiphenyl ether, dibromodiphenyl ether, dichlorodiphenyl sulfide, dibromodiphenyl sulfide, dichlorobiphenyl, dibromobiphenyl Compounds and mixtures thereof, these compounds may be block copolymerized. Of these, dihalogenated benzenes are preferred, and those containing p-dichlorobenzene of 80 mol% or more are particularly preferred.

  Further, for the purpose of increasing the viscosity of the polyarylene sulfide resin by using a branched structure, a polyhaloaromatic compound having 3 or more halogen substituents in one molecule may be used as a branching agent as desired. Examples of such polyhaloaromatic compounds include 1,2,4-trichlorobenzene, 1,3,5-trichlorobenzene, 1,4,6-trichloronaphthalene, and the like.

  Furthermore, polyhaloaromatic compounds having a functional group having active hydrogen such as amino group, thiol group, hydroxyl group can be mentioned. Specifically, 2,6-dichloroaniline, 2,5-dichloroaniline 2,4-dichloroaniline, 2,3-dichloroaniline and other dihaloanilines; 2,3,4-trichloroaniline, 2,3,5-trichloroaniline, 2,4,6-trichloroaniline, 3, Trihaloanilines such as 4,5-trichloroaniline; dihaloaminodiphenyl ethers such as 2,2′-diamino-4,4′-dichlorodiphenyl ether and 2,4′-diamino-2 ′, 4-dichlorodiphenyl ether Examples thereof include compounds in which the amino group is replaced by a thiol group or a hydroxyl group in a mixture thereof.

  In addition, active hydrogen-containing polyhalo compounds in which the hydrogen atom bonded to the carbon atom forming the aromatic ring in these active hydrogen-containing polyhaloaromatic compounds is substituted with another inert group, for example, a hydrocarbon group such as an alkyl group. Aromatic compounds can also be used.

  Among these various active hydrogen-containing polyhaloaromatic compounds, an active hydrogen-containing dihaloaromatic compound is preferable, and dichloroaniline is particularly preferable.

  Examples of the polyhaloaromatic compound having a nitro group include mono- or dihalonitrobenzenes such as 2,4-dinitrochlorobenzene and 2,5-dichloronitrobenzene; 2-nitro-4,4′-dichlorodiphenyl ether Dihalonitrodiphenyl ethers; dihalonitrodiphenyl sulfones such as 3,3′-dinitro-4,4′-dichlorodiphenyl sulfone; 2,5-dichloro-3-nitropyridine, 2-chloro-3,5 -Mono or dihalonitropyridines such as dinitropyridine; or various dihalonitronaphthalenes.

  The alkali metal sulfide used in the polymerization process of the polyarylene sulfide resin includes lithium sulfide, sodium sulfide, rubidium sulfide, cesium sulfide and a mixture thereof. Such alkali metal sulfides can be used as hydrates, aqueous mixtures or anhydrides. The alkali metal sulfide can also be derived from the reaction between an alkali metal hydrosulfide and an alkali metal hydroxide. Normally, a small amount of alkali metal hydroxide may be added to react with alkali metal hydrosulfide or alkali metal thiosulfate present in a trace amount in the alkali metal sulfide.

  The alkali metal hydrosulfide used in the polymerization process of the polyarylene sulfide resin includes lithium hydrosulfide, sodium hydrosulfide, rubidium hydrosulfide, cesium hydrosulfide, and mixtures thereof. Such alkali metal hydrosulfides can be used as hydrates, aqueous mixtures or anhydrides.

  Examples of the alkali metal hydroxide used in the polymerization process of the polyarylene sulfide resin include lithium hydroxide, sodium hydroxide, potassium hydroxide, rubidium hydroxide, cesium hydroxide, and the like. You may use, and may mix and use 2 or more types. Among these, lithium hydroxide, sodium hydroxide, and potassium hydroxide are preferable because they are easily available, and sodium hydroxide is particularly preferable.

Examples of the organic polar solvent used in the polymerization process of the polyarylene sulfide resin include formamide, acetamide, N-methylformamide, N, N-dimethylacetamide, tetramethylurea, N-methyl-2-pyrrolidone, 2-pyrrolidone, N- methyl -ε- caprolactam, .epsilon.-caprolactam, hexamethylphosphoramide, N- dimethyl propylene urea, 1,3-dimethyl-2-imidazolinone of which amides, ureas and lactams; sulfolane, sulfolane and dimethyl sulfolane Nitriles such as benzonitrile; ketones such as methyl phenyl ketone and mixtures thereof, among which N-methyl-2-pyrrolidone, 2-pyrrolidone, N-methyl-ε-caprolactam, ε -Caprolactam, hexamethi Phosphoramides, N- dimethyl propylene urea, amides having aliphatic cyclic structure of 1,3-dimethyl-2-imidazolinone is preferred.

  In the polymerization reaction of the polyarylene sulfide resin, the alkali metal sulfide is reacted with the polyhaloaromatic compound as a sulfidizing agent in the presence of these organic polar solvents. Alternatively, in the polymerization reaction of the polyarylene sulfide resin, the alkali metal hydrosulfide and alkali metal hydroxide are reacted with the polyhaloaromatic compound as a sulfidizing agent in the presence of these organic polar solvents. The polymerization conditions are generally in the range of 200 to 330 ° C., and the pressure should be in such a range as to keep the polymerization solvent and the polymerization monomer polyhaloaromatic compound in a substantially liquid phase. It is selected from the range of 1-20 MPa, preferably from the range of 0.1-2 MPa. The compounding quantity of a polyhalo aromatic compound has the range of 0.2 mol-5.0 mol with respect to 1 mol of sulfur atoms of the said sulfidizing agent.

As a specific embodiment for polymerizing a sulfidizing agent and a polyhaloaromatic compound in the presence of the organic polar solvent described above, for example,
1) A method using a polymerization aid such as an alkali metal carboxylate or lithium halide,
2) A method using a crosslinking agent such as an aromatic polyhalogen compound,
3) A method in which a polymerization reaction is carried out in the presence of a small amount of water and then water is added for further polymerization,
4) During the reaction between the alkali metal sulfide and the aromatic dihalogen compound, a method of cooling the gas phase part of the reaction vessel to condense a part of the gas phase in the reaction vessel and refluxing it to the liquid phase, etc. .
5) In the presence of a polyhaloaromatic compound, an alkali metal sulfide, or a hydrous alkali metal hydrosulfide and an alkali metal hydroxide, and an amide, urea or lactam having an aliphatic cyclic structure are reacted while being dehydrated. Obtained through a step of producing a slurry containing a solid alkali metal sulfide, a step of adding a polar organic solvent such as NMP and dehydrating by distilling off water after producing the slurry, followed by a dehydration step. In the resulting slurry, a polyhaloaromatic compound, an alkali metal hydrosulfide, and an alkali metal salt of an amide, urea or lactam hydrolyzate having an aliphatic cyclic structure are mixed with 1 mol of a polar organic solvent such as NMP. In contrast, polyarylene sulfide having a process of performing polymerization by reacting at a water content of 0.02 mol or less in the reaction system as an essential process. Method for manufacturing a resin.

  Among these, when a polyarylene sulfide resin is produced by the polymerization methods 1) to 4), more by-products are produced, and therefore the COD value contained in the wastewater after purification tends to be high. For this reason, particularly when producing a polyarylene sulfide resin by the polymerization methods 1) to 4), it is preferable to reduce the carboxyalkylamino group-containing compound which is a COD-causing substance in wastewater by the method of the present invention.

  In the production of the polyarylene sulfide resin, as a raw material for producing the polyarylene sulfide resin, for example, when the organic polar solvent is N-methyl-2-pyrrolidone and the polyhaloaromatic compound is p-dichlorobenzene, the carboxyalkyl As an amino group-containing compound, the following general formula (3)

（式中、Ｘはアルカリ金属原子または水素原子を表す。）で表されるものが得られる（この化合物を“ＣＰ−ＭＡＢＡ”と略記する）。

(Wherein X represents an alkali metal atom or a hydrogen atom) is obtained (this compound is abbreviated as “CP-MABA”).

  After the polymerization of the polyarylene sulfide resin, a crude reaction mixture containing the polyarylene sulfide resin, the alkali metal-containing inorganic salt, the carboxyalkylamino group-containing compound, and the organic polar solvent can be obtained. Next, the organic polar solvent is subjected to solid-liquid separation from the obtained crude reaction mixture to obtain a reaction mixture containing a polyarylene sulfide resin, an alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound. The solid-liquid separation is roughly classified into two types, a flash method and a quench method described later. The flash method is a method of recovering a solvent by evaporating the solvent and simultaneously recovering a solid substance, and is generally performed by heating under reduced pressure to distill off the solvent.

  On the other hand, the quench method is a method in which the polymerization reaction product is removed by cooling to recover the particulate polyarylene sulfide resin. Generally, after cooling the reaction slurry in a reaction kettle, the polyarylene sulfide resin is crystallized. For example, a solid-liquid separation method may be used. Solid-liquid separation in the Quench method is a method in which after separation using a centrifugal separator such as filtration or screw decanter, water is directly added to the obtained filtration residue to form a slurry, and then solid-liquid separation is repeated. For example, a method of removing the remaining solvent by heating the filtered residue in a non-oxidizing atmosphere can be used. The flash method is preferable because solids can be collected relatively easily, and the quench method is easy to control the particle size of the polyarylene sulfide resin, and the polymer particles contain alkali metal-containing inorganic salts and other salts during crystallization. Since it becomes difficult to take in impurities, it is preferable in that a high-purity polymer is obtained.

  Subsequently, an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound can be prepared by bringing the reaction mixture into contact with water and filtering off the polyarylene sulfide resin.

  Examples of the method of bringing the reaction mixture into contact with water, followed by solid-liquid separation and filtering off the polyarylene sulfide resin (hereinafter sometimes referred to as “washing”) include, for example, removing an organic polar solvent from the crude reaction mixture. A method in which water is added to the reaction slurry obtained by solid-liquid separation and stirred, followed by filtration using a filtration device, and a filtration residue containing moisture obtained by the filtration described above (hereinafter abbreviated as “water-containing cake”). And a method of adding water again to form a slurry, and a method of filtering, or a method of adding water again and filtering in a state where the water-containing cake is held in a filter.

  The amount of water added to the reaction slurry during the water washing is preferably in the range of 2 to 10 times the theoretical yield of the polyarylene sulfide finally obtained, from the viewpoint of washing efficiency, It is preferable to divide the water into 2 to 10 times, preferably 2 to 4 times, and wash it with water. The water washing is preferably performed in a nitrogen or air atmosphere in a water temperature range of 50 ° C. to 100 ° C. and a cleaning efficiency of 70 ° C. to 90 ° C., in particular. The water washing can be repeated once or a plurality of times. When water washing is repeated a plurality of times, the atmosphere and temperature conditions may be the same or different.

  The polyarylene sulfide resin separated by filtration may contain a trace amount of an alkali metal-containing inorganic salt or a carboxyalkylamino group-containing compound. Therefore, the polyarylene sulfide resin may be further solidified after contact with water in the range of 100 to 275 ° C. Liquid separation (hereinafter sometimes referred to as “hot water washing”), the polyarylene sulfide resin is filtered off, and the remaining aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound can be extracted. This aqueous solution can also be used in the present invention.

  The temperature of the hot water washing is preferably in the range of 120 to 275 ° C., for example, from the viewpoint of good extraction efficiency of the carboxyalkylamino group-containing compound. More specifically, it is preferable to perform the extraction treatment with hot water at 140 to 260 ° C. under the condition that the pressure of the gas phase in the reactor is 0.2 to 4.6 MPa. By such hydrothermal treatment, the remaining alkali metal contained in the polyarylene sulfide resin and the carboxyalkylamino group-containing compound can be more efficiently extracted into water, and then the polyarylene sulfide resin is filtered. By separating, an aqueous solution containing an alkali metal-containing inorganic salt and a carboxyalkylamino group-containing compound can be obtained.

  As a specific method for performing such hot water washing, there is a method of washing the polyarylene sulfide resin filtered off after the water washing with stirring in water under a predetermined pressure condition and temperature condition in a pressure vessel. The amount of water at the time of hot water washing is preferably 1.5 times to 10 times the mass of polyarylene sulfide, from the point that the extraction efficiency of the carboxyalkylamino group-containing compound is good. The hot water washing may be performed in two or more times. For example, when hot water washing is repeated twice, it is preferable to perform filtration between the first hot water washing and the second hot water washing to remove the carboxyalkylamino group-containing compound extracted by the first hot water washing. Moreover, after performing hot water washing once, it may filter and may carry out an above described water washing. This operation also promotes the removal of the carboxyalkylamino group-containing compound. Moreover, although the conditions of the 1st hot water washing process and the 2nd hot water washing process can be selected arbitrarily from said conditions, the temperature of the 1st hot water washing process is the temperature which exists in the range of 120 to 200 degreeC, for example. After setting and removing the first highly alkaline filtrate by filtration, the temperature of the second hot water washing step is set to a temperature higher than the temperature of the first hot water washing step, for example, in the range of 150 ° C. to 275 ° C. It is preferable to implement it from the viewpoint of chemical resistance of the apparatus used in the hot water washing.

  Furthermore, the pH can be adjusted by adding an acid or a base during hot water washing. In particular, in a carboxyalkylamino group-containing compound, X in the formula becomes an alkali metal atom and is easily extracted into water. It is preferable to control so that the pH is in the range of 11.0 or more and less than 13.0. Examples of the acid used at the time of hot water washing include hydrochloric acid, sulfuric acid, carbonic acid, acetic acid and the like, and among these, carbonic acid and acetic acid are preferable. Examples of the base used in the hot water washing include alkali metal hydroxides such as lithium hydroxide, sodium hydroxide, and potassium hydroxide, or sodium carbonate, ammonium carbonate, sodium phosphate, and the like. Among these, sodium hydroxide is preferable.

  In the present invention, washing with water can be carried out using a washing tank having a stirrer or a centrifuge for solid-liquid separation. However, the container has a stirring blade inside and a filter for filtration is arranged at the bottom. It can be carried out in a container having a mixing function. It is also possible to use a water washing tank having a stirrer or a centrifuge for solid-liquid separation even in hot water washing exceeding 100 ° C., but it has a stirring blade inside the container and is filtered at the bottom. It can be carried out in a closed type container provided with a filter for use or in a container having a mixing function capable of being sealed. In the present invention, water washing or hot water washing may be carried out continuously or in a batch manner.

  The filtered polyarylene sulfide resin may then be dried as it is to obtain a polyarylene sulfide resin powder. After further washing treatment, it is separated into solid and liquid, and dried to form a powder or granule. The polyarylene sulfide resin can be prepared.

  The aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound prepared via the polymerization methods 1) to 4) described above tends to contain a large amount of the carboxyalkylamino group-containing compound. Although the amount depends on the degree of washing in the water washing step, it is generally 2000 [mg / L] or more from an industrial viewpoint, and even after water washing, the amount is 1500 [mg / L] or more. Moreover, in the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound prepared through the polymerization method of 5) above, the aqueous washing is generally performed at 1500 [mg / L] or more. Even the ratio is 1100 [mg / L] or more.

(Process 1)
The aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound thus prepared is then adjusted to pH 6.0 or less by adding an acid. Thereby, the general formula (1) mainly becomes a carboxyalkylamino group-containing compound (hereinafter referred to as carboxyalkylamino group-containing compound (a1)) in which X in the formula is a hydrogen atom. In order to further improve the separation efficiency in the subsequent step 2, the pH range is preferably in the range of 2.5 to 5.5, more preferably in the range of 3.5 to 4.5. Examples of the acid used in this case include hydrochloric acid, sulfuric acid, carbonic acid, and acetic acid. Among these, hydrochloric acid is preferable. The acid can be added in the range of 0 to 60 ° C., more preferably in the range of 10 to 40 ° C. and the pressure in the range of 0 to 1.0 Pa.

(Process 2)
This invention has the process 2 which adds a polyhalo aromatic compound to the said aqueous solution, and isolate | separates into the organic phase containing the said carboxyalkylamino group containing compound and a polyhalo aromatic compound, and the aqueous phase containing an alkali metal containing inorganic salt.

  In step 2, the polyhaloaromatic compound is added as a water-insoluble solvent to the aqueous solution containing the alkali metal-containing inorganic salt pH adjusted in acid and the carboxyalkylamino group-containing compound (a1) obtained in step 1, The organic phase containing the carboxyalkylamino group-containing compound (a1) and the polyhaloaromatic compound and the aqueous phase containing the alkali metal-containing inorganic salt are separated.

  As a polyhalo aromatic compound, the same thing as what was used at the polymerization process of the said polyarylene sulfide resin can be used.

  The amount of polyhaloaromatic compound added in step 2 is not particularly limited as long as it is an amount that undergoes phase separation after mixing of the aqueous solution and the polyhaloaromatic compound. Specifically, although depending on the type and concentration of the carboxyalkylamino group-containing compound (a1) in the polyhaloaromatic compound, the type of the solvent itself, etc., for example, 1 to 200 parts by mass with respect to 100 parts by mass of the aqueous solution The range is preferably 5 to 50 parts by mass.

The mixing of the aqueous solution and the polyhaloaromatic compound in step 2 is, for example, a temperature range in which water and the polyhaloaromatic compound do not coagulate and water and the polyhaloaromatic compound do not evaporate, preferably 60 to 90 ° C. More preferably, a temperature range of 70 to 80 ° C. can be mentioned.
The aqueous solution and the polyhaloaromatic compound in step 2 may be mixed using a mixing device such as a stirrer or a static mixer.

(Steps 3 and 4)
In the present invention, the aqueous solution containing the alkali metal-containing inorganic salt phase-separated in step 2 and the organic phase (water-insoluble solvent phase) containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound are separately provided. As the step of recovering, “step 3 of removing the organic phase containing the separated carboxyalkylamino group-containing compound and polyhaloaromatic compound and recovering the aqueous solution containing the alkali metal-containing inorganic salt” or “separated alkali metal And removing the aqueous phase containing the containing inorganic salt and recovering the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound.

  The phase-separated organic phase containing the carboxyalkylamino group-containing compound (a1) and polyhaloaromatic compound and the aqueous phase containing the alkali metal-containing inorganic salt are separated and recovered efficiently by known means. As such a method, it is possible to adopt separation and recovery means such as decantation after standing, but in order to increase the recovery efficiency, industrially, mixing for sufficient contact ( Step 2, Step 3 and Step 4 are carried out using a so-called mixer / settler type separation / extraction apparatus equipped with a (mixer) unit and a separation (settler) unit that separates this and keeps the respective counterflows uniform. It is preferable to carry out simultaneously or continuously.

  The operations of Step 3 and Step 4 can be performed in any of a pressurized state, a normal pressure state, and a reduced pressure state, and are preferably performed in a normal pressure state from the simplicity of the apparatus. Moreover, although it can also carry out in non-oxidizing atmospheres, such as nitrogen and a noble gas, it is preferable to carry out in air | atmosphere from the simplicity of an apparatus.

  In order to reduce the COD value, a polyhaloaromatic compound may be further added to the phase-separated aqueous phase, and Step 2 and Step 3 may be repeated again. Similarly, in order to improve the recovery rate of the carboxyalkylamino group-containing compound, a polyhaloaromatic compound may be added to the phase-separated aqueous phase, and Step 2 and Step 4 may be repeated again.

  The COD value of the aqueous solution containing the alkali metal-containing inorganic salt obtained through the step 3 is 20% with respect to the COD value of the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound subjected to the step 1. Thus, it can be reduced to 40% or more, more preferably 70% or more. Furthermore, the carboxyalkylamino group-containing compound can be reduced to below the detection limit by repeating Step 2 and Step 3.

  On the other hand, the carboxyalkylamino group-containing compound obtained through step 4 is separated from the aqueous solution containing the alkali metal-containing inorganic salt and recovered as a carboxyalkylamino group-containing compound and a polyhaloaromatic compound, and the carboxyalkylamino group-containing compound The recovery rate (extraction rate) is 40% on a mass basis with respect to the carboxyalkylamino group-containing compound contained in the aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound subjected to Step 1. Thus, the range is preferably 50% or more, more preferably 75% or more, and still more preferably 90% or more. Furthermore, it is also possible to make it 99% or more by repeating the said process 2 and the process 4.

  The composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained through the step 4 can be used as a polymerization raw material for the polyarylene sulfide resin.

  Moreover, the trace amount polyhaloaromatic compound may be contained as an impurity in the aqueous solution containing the alkali metal-containing inorganic salt obtained through the step 3. For this reason, the aqueous solution containing the alkali metal-containing inorganic salt obtained through the step 3 is preferably cooled to the melting point of the polyhaloaromatic compound added in the step 2, preferably 50 ° C. or less, more preferably room temperature or less. . When the polyhaloaromatic compound is present as an impurity, it is crystallized as a solid content, so that it can be easily removed by a separation operation such as filtration, and the purity of an aqueous solution containing an alkali metal-containing inorganic salt can be given. On the other hand, the polyhaloaromatic compound separated and removed and recovered can be reused in Step 2, and can also be used as a polymerization raw material for polyarylene sulfide resin.

(Process 5)
Further, in the present invention, the composition containing the carboxyalkylamino group-containing compound (a1) and the polyhaloaromatic compound recovered in Step 4 is further added with an alkaline aqueous solution to separate the polyhaloaromatic compound. Can also be performed.
In step 5, by adding an alkaline aqueous solution to the carboxyalkylamino group-containing compound (a1) in the composition, mainly the carboxyalkylamino group-containing compound wherein X in the general formula (1) is an alkali metal atom (Hereinafter referred to as a carboxyalkylamino group-containing compound (a2)), which is separated on the aqueous phase side.

  The alkaline aqueous solution used in Step 5 can be prepared using the same alkali metal hydroxide or alkali metal sulfide as used in the polymerization step of the polyarylene sulfide resin in Step 1. There is no particular problem if the concentration of the alkali metal hydroxide or alkali metal sulfide in the alkaline aqueous solution is adjusted to be equal to or higher than that of the carboxyalkylamino group-containing compound (a1). The range is from 2 to 49% by mass, preferably from 1.0 to 10.0% by mass.

(Steps 6 and 7)
Furthermore, the present invention relates to “including the carboxyalkylamino group-containing compound by removing the polyhaloaromatic compound from the aqueous solution containing the carboxyalkylamino group-containing compound (a2) phase-separated in step 5 and the polyhaloaromatic compound. Step 6 ”for recovering the aqueous solution” or “Step 7 for recovering the polyhaloaromatic compound by removing the aqueous solution containing the separated carboxyalkylamino group-containing compound”.

In Step 5, after separating the aqueous solution containing the carboxyalkylamino group-containing compound (a2) and the polyhaloaromatic compound, the method for recovering the aqueous solution containing the carboxyalkylamino group-containing compound (a2) or the polyhaloaromatic compound, This can be done by known means. As such a method, it is possible to adopt a separation and recovery means such as decantation after standing, but in order to increase the recovery efficiency in particular, a mixer / settler type separation / extraction device is used industrially. It is preferable to carry out.
Further, the polyhaloaromatic compound recovered in step 7 can be reused in step 2.

  In the present invention, the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained in Step 4 is added to an organic polar solvent, and the polyhaloaromatic compound and (i) an alkali metal sulfide are added. Or (ii) the form of the manufacturing method of the polyarylene sulfide resin which makes an alkali metal hydrosulfide and an alkali metal hydroxide react is included. In the present invention, the aqueous solution containing the carboxyalkylamino group-containing compound obtained in Step 6 is added to an organic polar solvent to add a polyhaloaromatic compound and (i) an alkali metal sulfide, or (ii) ) A method for producing a polyarylene sulfide resin characterized by reacting an alkali metal hydrosulfide and an alkali metal hydroxide is also included. By adding the carboxyalkylamino group-containing compound to the raw material of the polyarylene sulfide resin, a polyarylene sulfide resin excellent in epoxy adhesiveness can be produced.

  Further, the carboxyalkylamino group-containing compound obtained in Step 4 or Step 6 acts as a thermal oxidation cross-linking agent, and is a ratio in the range of 0.002 to 0.01 parts by mass with respect to 1 part by mass of the polyarylene sulfide resin. In addition to improving the melt stability of the resin by suppressing the thickening at the time of melt molding, a cross-linked polyarylene sulfide resin having a high crystallization speed at the time of molding and solidification is produced. be able to.

  Conventionally, although the carboxyalkylamino group-containing compound has been treated as industrial waste, it is separated from the alkali metal-containing inorganic salt through Step 4 or Step 6 above, so as to be used as a raw material in the polyarylene sulfide polymerization step, or The polyarylene sulfide resin can be reused as an additive during thermal oxidation crosslinking. For this reason, the industrial waste discharged | emitted in the manufacturing process of polyarylene sulfide resin can be reduced.

  As described above, the polyarylene sulfide resin polymerized using a carboxyalkylamino group-containing compound as a raw material, and the crosslinked polyarylene sulfide resin obtained by thermal oxidative crosslinking treatment as an additive, impair the effects of the present invention. As long as there are no additives, additives such as a mold release agent, a colorant, a heat stabilizer, an ultraviolet stabilizer, a foaming agent, a rust inhibitor, a flame retardant, a lubricant, a coupling agent, and a filler can be contained. Furthermore, the following synthetic resins and elastomers can also be mixed and used. These synthetic resins include polyester, polyamide, polyimide, polyetherimide, polycarbonate, polyphenylene ether, polysulfone, polyethersulfone, polyetheretherketone, polyetherketone, polyarylene, polyethylene, polypropylene, polytetrafluoroethylene, Examples thereof include poly (difluoroethylene), polystyrene, ABS resin, epoxy resin, silicone resin, phenol resin, urethane resin, and liquid crystal polymer. Examples of the elastomer include polyolefin rubber, fluorine rubber, and silicone rubber.

  The polyarylene sulfide resin thus obtained is made into a molded product excellent in heat resistance, molding processability, dimensional stability, etc. by various melt processing methods such as injection molding, extrusion molding, compression molding and blow molding. For example, electrical and electronic parts such as connectors, printed boards, and sealing molded products, automotive parts such as lamp reflectors and various electrical components, interior materials such as various buildings and aircraft and automobiles, and OA equipment parts -It can be widely used as injection molding / compression molding products such as precision parts such as camera parts and watch parts, or extrusion molding / pulling molding products such as fibers, films, sheets, and pipes.

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

[Reference Example] Production of polyarylene sulfide resin In a 150 liter autoclave with a pressure gauge, a thermometer, a condenser connected with a stirring blade and a bottom valve, 14.148 parts of 45% sodium hydrosulfide (47.55 mass% NaSH), Charged 9.317 parts of 48% caustic soda (48.7 wt% NaOH) and 38.0 parts of N-methyl-2-pyrrolidone. While stirring under a nitrogen stream, the temperature was raised to 209 ° C. to distill 12.150 parts of water (the amount of water remaining was 1.13 mol per 1 mol of NaSH). Thereafter, the autoclave was sealed and cooled to 180 ° C., and 17.129 parts of paradichlorobenzene and 16.0 parts of N-methyl-2-pyrrolidone were charged. The temperature was raised by pressurizing to 0.1 MPa with a gauge pressure using nitrogen gas at a liquid temperature of 150 ° C. The reaction was allowed to proceed with stirring at a liquid temperature of 260 ° C. for 3 hours, and the upper part of the autoclave was sprinkled to cool it. Next, the temperature was lowered and cooling of the upper part of the autoclave was stopped. The upper part of the autoclave was kept constant during cooling to prevent the liquid temperature from dropping. The maximum pressure during the reaction was 0.86 MPa. After the reaction, the mixture was cooled, and at a temperature of 170 ° C., a solution containing 0.284 parts of oxalic acid dihydrate in 0.663 parts of N-methyl-2-pyrrolidone was injected under pressure. After stirring for 30 minutes, it is cooled, the bottom valve is opened at 100 ° C., the reaction slurry is transferred to a flat plate filter and filtered under pressure at 120 ° C., 16.0 parts of N-methyl-2-pyrrolidone is added, and the pressure is increased. Filtered. After filtration, the mixture was stirred for 2 hours at 150 ° C. under reduced pressure using a vacuum dryer with a stirring blade to distill off N-methyl-2-pyrrolidone. Next, 90 parts of 70 ° C. warm water was added and stirred, followed by filtration. Further, 25 parts of 70 ° C. warm water was added and filtered, and the filtrate was collected to prepare “aqueous solution (A)”. The pH of the aqueous solution (A) was 9.3, the CP-MABA concentration was 1722 [ppm], the COD was 2103 [mg / L], and the polyarylene sulfide resin concentration was 0 [mass%].

[Example 1]
1 mol / L hydrochloric acid was added to 500 ml of the aqueous solution (A) with stirring to adjust the pH to 4.0 (denoted as aqueous solution (B)). Thereafter, 400 ml of pH-adjusted aqueous solution (B) was put in a separatory funnel equipped with a heating device, and further 40 ml of p-dichlorobenzene (melting point 53 ° C.) melted by heating to 70 ° C. was heated to 70 ° C. After shaking for 5 minutes, it was allowed to stand. After phase separation into a p-dichlorobenzene phase (organic phase) and an aqueous phase, the separated p-dichlorobenzene phase (a) and aqueous phase (a) were decanted and recovered separately. Thereafter, the CP-MABA concentration in the p-dichlorobenzene phase (a) was measured, and the extraction rate of CP-MABA extracted from the aqueous solution (A) into the p-dichlorobenzene phase (a) (hereinafter referred to as “CP-MABA extraction rate”). a ”) and the COD value of the aqueous phase (a) was measured. The results are shown in Table 1.

[Example 2]
The same procedure as in Example 1 was conducted except that 1 mol / L hydrochloric acid was added to 500 ml of the aqueous solution (A) and the pH was adjusted to 5.0, and the CP-MABA extraction rate and the COD of the aqueous phase were measured. The results are shown in Table 1.

Example 3
The same procedure as in Example 1 was conducted except that 1 mol / L hydrochloric acid was added to 500 ml of the aqueous solution (A) while stirring to adjust the pH to 2.0, and the CP-MABA extraction rate and the COD of the aqueous phase were measured. The results are shown in Table 1.

Example 4
The CP-MABA extraction rate was carried out in the same manner as in Example 1 except that 20 ml of 70 ° C. molten p-dichlorobenzene (melting point 53 ° C.) was used instead of 40 ml of 70 ° C. molten p-dichlorobenzene (melting point 53 ° C.). The COD of the aqueous phase was measured. The results are shown in Table 1.

Example 5
1 mol / L hydrochloric acid was added to 500 ml of the aqueous solution (A) with stirring to adjust the pH to 2.0, and 70 ° C. molten p-dichlorobenzene (melting point 53 ° C.) instead of 40 ml was melted at 70 ° C. -It carried out similarly to Example 1 except having set it as 20 ml of dichlorobenzene (melting | fusing point 53 degreeC), and measured CP-MABA extraction rate and COD of the water phase. The results are shown in Table 1.

[Comparative Example 1]
Except not adjusting pH of aqueous solution (A), it carried out like Example 1 and measured CP-MABA extraction rate and COD of the water phase. The results are shown in Table 2.

[Comparative Example 2]
The same procedure as in Example 1 was conducted except that 1 mol / L hydrochloric acid was added to 500 ml of the aqueous solution (A) while stirring to adjust the pH to 6.5, and the CP-MABA extraction rate and the COD of the aqueous phase were measured. The results are shown in Table 2.

  The extraction rate of CP-MABA extracted from the aqueous solution (A) into the water-insoluble solvent phase (organic phase) and the COD of the aqueous phase were as follows.

[CP-MABA extraction rate]
The CP-MABA extraction rate was calculated by measuring the CP-MABA concentration in the liquid by HPLC.
Sample preparation: When CP-MABA was contained in p-dichlorobenzene, the p-dichlorobenzene was distilled off with an evaporator, and then the mobile phase of HPLC was added to the residue and dissolved to prepare a measurement sample. When CP-MABA was contained in the aqueous phase, it was prepared by adding the mobile phase as it was.
The measurement sample was subjected to HPLC measurement, the concentration in the solution was determined from the peak area and calibration curve of the same retention time as the standard sample prepared by the following method, and the CP-MABA extraction rate was calculated from the following formula.

(Synthesis of standard substance: CP-MABA)
83.4 g (1.0 mol) of 48% NaOH aqueous solution and 297.4 g (3.0 mol) of N-methyl-2-pyrrolidone were charged in a pressure vessel equipped with a stirrer and stirred at 230 ° C. for 3 hours. After the stirring was completed, the valve was opened with the temperature kept at 230 ° C., the pressure was released, and the pressure was reduced to 0.1 MPa at 230 ° C., which is about the vapor pressure of N-methyl-2-pyrrolidone, and water was distilled off. Then, it sealed again and the temperature was reduced to about 200 degreeC.

  147.0 g (1.0 mol) of p-dichlorobenzene was heated and dissolved under a temperature condition of 60 ° C. or higher, charged into the reaction mixture, heated to 250 ° C., and stirred for 4 hours. After completion of this stirring, the mixture was cooled to room temperature. The reaction rate of p-dichlorobenzene was 31 mol%. After cooling, the contents were taken out, water was added, and the mixture was stirred. Unreacted p-dichlorobenzene remained as an insoluble matter and was removed by filtration.

  Next, hydrochloric acid was added to the aqueous solution as the filtrate to adjust the pH of the aqueous solution to 4. At this time, brown oily CP-MABA (hydrogen type) was formed in the aqueous solution. Chloroform was added thereto to extract a brown oily substance. Since the aqueous phase at this time contained N-methyl-2-pyrrolidone and its ring-opened product, 4-methylaminobutyric acid (hereinafter abbreviated as “MABA”), the aqueous phase was discarded. The chloroform phase was washed twice with water.

  In a state where water was added to the chloroform phase to form a slurry, a 48% NaOH aqueous solution was added to adjust the pH of the slurry to 13. At this time, CP-MABA was converted to a sodium salt and moved to the aqueous phase, and the chloroform phase was discarded because p-chloro-N-methylaniline and N-methylaniline as by-products were dissolved in the chloroform phase. The aqueous phase was washed twice with chloroform.

  Dilute hydrochloric acid was added to the aqueous solution to adjust the pH of the aqueous solution to 1 or less. At this time, CP-MABA became hydrochloride and remained in the aqueous solution, so chloroform was added to the aqueous solution to extract p-chlorophenol as a by-product. The chloroform phase in which p-chlorophenol was dissolved was discarded.

  A 48% aqueous NaOH solution was added to the remaining aqueous solution to adjust the pH of the aqueous solution to 4. As a result, the hydrochloride of CP-MABA was neutralized, and brown oily CP-MABA (hydrogen type) was precipitated from the aqueous solution. CP-MABA (hydrogen type) was extracted with chloroform, and chloroform was removed under reduced pressure to obtain CP-MABA (hydrogen type).

[Measurement of COD]
COD by KMnO ₄ was measured according to JIS K0120.

[Measurement of polyarylene sulfide resin concentration]
The polyarylene sulfide resin concentration in the aqueous solution (A) was measured as follows.
To 100 parts by mass of the aqueous solution (A), 20 parts by mass of chloroform was added, mixed and extracted with an analytical funnel, and separated to separate a chloroform layer and an aqueous layer. The chloroform layer was measured with a liquid chromatograph apparatus using chloroform as the mobile phase, and the area area (A) obtained by removing the peak of the carboxyalkylamino group-containing compound from the obtained peak was determined. However, the peak of the carboxyalkylamino group-containing compound was determined by measuring in advance a chloroform solution of the carboxyalkylamino group-containing compound at a predetermined concentration and measuring the retention time. Separately, the area area (B) of a chloroform solution having a polyarylene sulfide resin concentration of 0.32 wt% was obtained, and the polyarylene sulfide resin concentration in the aqueous solution (A) was calculated from the following formula.

Claims (8)

Alkali metal-containing inorganic salt and the following general formula (1)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom.) From an aqueous solution containing a carboxyalkylamino group-containing compound represented by: A method for producing the carboxyalkylamino group-containing compound by separating the alkylamino group-containing compound,
(1) Step 1 of adjusting an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound to pH 6.0 or less,
(2) Step 2, in which a polyhaloaromatic compound is added to the aqueous solution and separated into an organic phase containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound and an aqueous phase containing an alkali metal-containing inorganic salt,
(3) Step 3 of removing the organic phase containing the separated carboxyalkylamino group-containing compound and polyhaloaromatic compound to recover an aqueous solution containing an alkali metal-containing inorganic salt;
And the polyhaloaromatic compound is at least dihalogenated benzene, and the organic polar solvent is N-methyl-2-pyrrolidone, N-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam and 1,3 A method for producing an aqueous solution containing an alkali metal-containing inorganic salt, characterized in that it is at least one selected from the group consisting of dimethyl-2-imidazolinone . Alkali metal-containing inorganic salt and the following general formula (1)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom.) An aqueous solution containing a carboxyalkylamino group-containing compound represented by:
In an organic polar solvent, a polyhaloaromatic compound and (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are reacted to form a polyarylene sulfide resin and an alkali metal. After obtaining a crude reaction mixture containing a containing inorganic salt, the carboxyalkylamino group-containing compound and the organic polar solvent, the organic polar solvent is solid-liquid separated from the crude reaction mixture to obtain a polyarylene sulfide resin and an alkali metal-containing inorganic salt. And a carboxyalkylamino group-containing compound is obtained, followed by a purification step in which the reaction mixture is brought into contact with water and the polyarylene sulfide resin is filtered off. Method. Alkali metal-containing inorganic salt and the following general formula (1)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom.) From an aqueous solution containing a carboxyalkylamino group-containing compound represented by: A method for producing the carboxyalkylamino group-containing compound by separating the alkylamino group-containing compound,
(1) Step 1 of adjusting an aqueous solution containing the alkali metal-containing inorganic salt and the carboxyalkylamino group-containing compound to pH 6.0 or less,
(2) Step 2, in which a polyhaloaromatic compound is added to the aqueous solution and separated into an organic phase containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound and an aqueous phase containing an alkali metal-containing inorganic salt,
(4) separated by removing the aqueous phase containing the inorganic salt containing an alkali metal, it has a step 4, to recover the organic phase comprising said carboxyalkyl amino group-containing compound and polyhalo aromatic compound and polyhalo aromatic The compound is at least dihalogenated benzene, and the organic polar solvent comprises N-methyl-2-pyrrolidone, N-pyrrolidone, N-methyl-ε-caprolactam, ε-caprolactam and 1,3-dimethyl-2-imidazolinone A method for producing a composition comprising a carboxyalkylamino group-containing compound and a polyhaloaromatic compound, which is at least one selected from the group . Alkali metal-containing inorganic salt and the following general formula (1)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Represents an alkylene group having 3 to 5 carbon atoms, X represents a hydrogen atom or an alkali metal atom.) An aqueous solution containing a carboxyalkylamino group-containing compound represented by:
In an organic polar solvent, a polyhaloaromatic compound and (i) an alkali metal sulfide or (ii) an alkali metal hydrosulfide and an alkali metal hydroxide are reacted to form a polyarylene sulfide resin and an alkali metal. After obtaining a crude reaction mixture containing a containing inorganic salt, the carboxyalkylamino group-containing compound and the organic polar solvent, the organic polar solvent is solid-liquid separated from the crude reaction mixture to obtain a polyarylene sulfide resin and an alkali metal-containing inorganic salt. 4. A process according to claim 3, wherein the reaction mixture is obtained through a purification step comprising contacting the reaction mixture with water and filtering off the polyarylene sulfide resin. Method. (5) An alkaline aqueous solution is further added to the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained by the production method according to claim 3, and the polyhaloaromatic compound and the following general formula ( 2)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Is an alkylene group having 3 to 5 carbon atoms, and X ′ represents an alkali metal atom.) And an aqueous solution containing a carboxyalkylamino group-containing compound represented by step 5;
(6) A method for producing an aqueous solution containing a carboxyalkylamino group-containing compound, comprising removing the separated polyhaloaromatic compound and recovering an aqueous solution containing the carboxyalkylamino group-containing compound. (5) An alkaline aqueous solution is further added to the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained by the production method according to claim 3, and the polyhaloaromatic compound and the following general formula ( 2)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Is an alkylene group having 3 to 5 carbon atoms, and X ′ represents an alkali metal atom.) And an aqueous solution containing a carboxyalkylamino group-containing compound represented by step 5;
(7) removing the aqueous solution containing the separated carboxyalkylamino group-containing compound and recovering the polyhaloaromatic compound, and using the polyhaloaromatic compound obtained in step 7 in step 2 The manufacturing method of Claim 1 characterized by the above-mentioned. (5) An alkaline aqueous solution is further added to the composition containing the carboxyalkylamino group-containing compound and the polyhaloaromatic compound obtained by the production method according to claim 3, and the polyhaloaromatic compound and the following general formula ( 2)

(Wherein, n is 0, Y ¹ is a halogen atom, Y ² is a hydrogen atom or a halogen atom, R ¹ represents a hydrogen atom or an alkyl group or a cyclohexyl group having 1 to 3 carbon atoms, R ² Is an alkylene group having 3 to 5 carbon atoms, and X ′ represents an alkali metal atom.) And an aqueous solution containing a carboxyalkylamino group-containing compound represented by step 5;
(7) removing the aqueous solution containing the separated carboxyalkylamino group-containing compound to recover the polyhaloaromatic compound, and using the polyhaloaromatic compound obtained in step 7 in step 2 The manufacturing method of Claim 3 characterized by these. An aqueous solution containing an alkali metal-containing inorganic salt obtained by the production method of claim 1 is cooled below the melting point of the polyhaloaromatic compound added in the step 2, and the precipitated solid content is separated and removed. A method for producing an aqueous solution containing an inorganic salt.