A method for preparing polyarylene sulfide that can control a viscosity grade thereof by adjusting the molar ratio of water and amide-based compounds present in a polymerization reaction.

The production method of the present invention includes: a supplying step of supplying reaction raw materials to at least one of a plurality of reaction vessels that mutually communicate through a gas phase; a polymerizing step of carrying out a polymerization reaction; and a step of removing at least some of the water present in the reaction vessels. Each of the steps is carried out in parallel, and a reaction mixture is transferred sequentially between the reaction vessels. The amount of water contained in the reaction mixture in at least one of the reaction vessels is from 0.1 moles to less than 3 moles per mole of a sulfur source, and the total amount of water contained in the reaction raw materials that are supplied is 3 moles or more per mole of the sulfur source.

The production method of the present invention includes: a supplying step of supplying reaction raw materials to at least one of a plurality of reaction vessels that mutually communicate through a gas phase; a polymerizing step of carrying out a polymerization reaction; and a step of removing at least some of the water present in the reaction vessels. Each of the steps is carried out in parallel, and a reaction mixture is transferred sequentially between the reaction vessels. The amount of water contained in the reaction mixture in at least one of the reaction vessels is from 0.1 moles to less than 3 moles per mole of a sulfur source, and the total amount of water contained in the reaction raw materials that are supplied is 3 moles or more per mole of the sulfur source.

Provided is a PAS production method and a PAS production apparatus wherein, in a gas-liquid system including a gas phase containing water, a dihalo aromatic compound, and hydrogen sulfide and a liquid phase containing a polar organic solvent and PAS, the dihalo aromatic compound and the hydrogen sulfide that can be volatilized at the time of dehydration from the gas phase can be recovered. The PAS production method according to the present invention includes: a condensation step of obtaining a first intermediate gas phase containing a dihalo aromatic compound and hydrogen sulfide and a first intermediate liquid phase containing water, a dihalo aromatic compound, and a sulfur source by condensation from the gas phase in the gas-liquid; a first recovery step of bringing the first intermediate gas phase into contact with a polar organic solvent to obtain a first recovered gas phase containing hydrogen sulfide and a first recovered liquid phase containing a polar organic solvent, a dihalo aromatic compound, and a sulfur source; and a second recovery step of bringing the first recovered gas phase into contact with an alkali metal hydroxide aqueous solution to obtain a second recovered liquid phase containing water, a sulfur source, and an alkali metal hydroxide.

Provided is a PAS production method and a PAS production apparatus wherein, in a gas-liquid system including a gas phase containing water, a dihalo aromatic compound, and hydrogen sulfide and a liquid phase containing a polar organic solvent and PAS, the dihalo aromatic compound and the hydrogen sulfide that can be volatilized at the time of dehydration from the gas phase can be recovered. The PAS production method according to the present invention includes: a condensation step of obtaining a first intermediate gas phase containing a dihalo aromatic compound and hydrogen sulfide and a first intermediate liquid phase containing water, a dihalo aromatic compound, and a sulfur source by condensation from the gas phase in the gas-liquid; a first recovery step of bringing the first intermediate gas phase into contact with a polar organic solvent to obtain a first recovered gas phase containing hydrogen sulfide and a first recovered liquid phase containing a polar organic solvent, a dihalo aromatic compound, and a sulfur source; and a second recovery step of bringing the first recovered gas phase into contact with an alkali metal hydroxide aqueous solution to obtain a second recovered liquid phase containing water, a sulfur source, and an alkali metal hydroxide.

There is provided a method and an apparatus for efficiently recovering an amide-based compound such as N-methyl-2-pyrrolidone from an aqueous solution containing an amide-based compound such as N-methyl-2-pyrrolidone.

There is provided a method and an apparatus for efficiently recovering an amide-based compound such as N-methyl-2-pyrrolidone from an aqueous solution containing an amide-based compound such as N-methyl-2-pyrrolidone.

To provide a polyarylene sulfide (hereinafter, PAS) manufacturing method and PAS manufacturing device that further eliminates processing costs in manufacturing PAS, by recovering from solid content containing an unreacted sulfur source and alkali metal halide produced as a byproduct the sulfur source and the solid content with a reduced amount of the sulfur source, and then conveniently and easily reusing the unreacted sulfur source without performing a large-scale process. A method of manufacturing PAS according to the present invention comprises: a polymerizing step of producing PAS; an extracting step of bringing an extraction solvent into content with solid content produced in the polymerizing step, and extracting at least a portion of a sulfur source from the solid content; a recovering step of separating and recovering the solid content passing through the extracting step and an extraction liquid produced in the extracting step; and a recycling step of supplying at least a portion of the extraction liquid preferably as at least a portion of PAS produced raw material in the polymerizing step; where the extraction solvent is (1) a protic organic solvent or (2) a mixed solvent containing water and an organic solvent, and the amount of the sulfur source in the solid content recovered in the recovering step is 2 parts by mass or less with regard to 100 parts by mass of the alkali metal halide.

To provide a polyarylene sulfide (hereinafter, PAS) manufacturing method and PAS manufacturing device that further eliminates processing costs in manufacturing PAS, by recovering from solid content containing an unreacted sulfur source and alkali metal halide produced as a byproduct the sulfur source and the solid content with a reduced amount of the sulfur source, and then conveniently and easily reusing the unreacted sulfur source without performing a large-scale process. A method of manufacturing PAS according to the present invention comprises: a polymerizing step of producing PAS; an extracting step of bringing an extraction solvent into content with solid content produced in the polymerizing step, and extracting at least a portion of a sulfur source from the solid content; a recovering step of separating and recovering the solid content passing through the extracting step and an extraction liquid produced in the extracting step; and a recycling step of supplying at least a portion of the extraction liquid preferably as at least a portion of PAS produced raw material in the polymerizing step; where the extraction solvent is (1) a protic organic solvent or (2) a mixed solvent containing water and an organic solvent, and the amount of the sulfur source in the solid content recovered in the recovering step is 2 parts by mass or less with regard to 100 parts by mass of the alkali metal halide.

Described here are polyphenylene sulfide (PPS) polymers having significantly improved processability. It was surprisingly found that PPS polymers, terminated with specific end-capping agents in specific amounts, had significantly improved melt stability. Because of the significantly improved melt stability, the PPS polymers can be advantageously incorporated into melt processing techniques.