According to the present invention, an alkali metal salt such as NaCl which is a major by-product of polyarylene sulfide polymerization may be recycled in the dehydration reaction for the preparation of a sulfur source, thereby providing a method of preparing a polyarylene sulfide with a high yield in an economical manner.

According to the present invention, an alkali metal salt such as NaCl which is a major by-product of polyarylene sulfide polymerization may be recycled in the dehydration reaction for the preparation of a sulfur source, thereby providing a method of preparing a polyarylene sulfide with a high yield in an economical manner.

The continuous dehydration method for a raw material mixture to be used in the production of PAS includes supply and dehydration of the raw material mixture and extraction of the raw material mixture having a water content reduced by the dehydration, the supply, dehydration and extraction being carried out concurrently in parallel. A dehydration efficiency index determined according to Equation (1) is not less than 0.3. In Equation (1), the dehydration time is a period of time until a moisture content per mole of the sulfur source in the raw material mixture having a reduced water content reaches not greater than 1.7 mol, including moisture consumed by the hydrolysis of the organic polar solvent.
Dehydration efficiency index=[Number of moles (mol) of the sulfur source in the raw material mixture having a reduced water content]/[Dehydration time (hr)×(Total internal volume (L) of the dehydration tanks).sup.2/3]  (1)

The continuous dehydration method for a raw material mixture to be used in the production of PAS includes supply and dehydration of the raw material mixture and extraction of the raw material mixture having a water content reduced by the dehydration, the supply, dehydration and extraction being carried out concurrently in parallel. A dehydration efficiency index determined according to Equation (1) is not less than 0.3. In Equation (1), the dehydration time is a period of time until a moisture content per mole of the sulfur source in the raw material mixture having a reduced water content reaches not greater than 1.7 mol, including moisture consumed by the hydrolysis of the organic polar solvent.
Dehydration efficiency index=[Number of moles (mol) of the sulfur source in the raw material mixture having a reduced water content]/[Dehydration time (hr)×(Total internal volume (L) of the dehydration tanks).sup.2/3]  (1)

A triazine ring-containing polymer including a repeating unit represented by Formula (1) and having a number average molecular weight of greater than about 20000 g/mol and less than or equal to about 50000 g/mol: ##STR00001## wherein, in Formula (1), R.sup.1 is each independently a C1 to C5 alkyl group and R.sup.2 is each independently a divalent group having at least one aromatic hydrocarbon group.

A method of producing a polyarylene sulfide (PAS) with a high nitrogen content in the PAS, the method thereof improving the characteristics of the PAS while reducing the amount of organic by-products, and using a plurality of reaction vessels that are in communication with each other through a gas phase. In the production method, a supply step, a water removal step, a polymerizing step, and a recovering step are performed in parallel. A polar organic solvent, a sulfur source, and a dihalo aromatic compound are used as reaction raw materials. A supply amount of the polar organic solvent used as a reaction raw material is 5 mol or less per mole of the sulfur source used as a reaction raw material. The polar organic solvent has a bond represented by —RO—N—, where R is C or P.

A method of producing a polyarylene sulfide (PAS) with a high nitrogen content in the PAS, the method thereof improving the characteristics of the PAS while reducing the amount of organic by-products, and using a plurality of reaction vessels that are in communication with each other through a gas phase. In the production method, a supply step, a water removal step, a polymerizing step, and a recovering step are performed in parallel. A polar organic solvent, a sulfur source, and a dihalo aromatic compound are used as reaction raw materials. A supply amount of the polar organic solvent used as a reaction raw material is 5 mol or less per mole of the sulfur source used as a reaction raw material. The polar organic solvent has a bond represented by —RO—N—, where R is C or P.

The present disclosure relates to a preparation method of a polyarylene sulfide, and this method may produce a polyarylene sulfide having properties equal to or higher than those of the conventional method with a high molecular weight at a high yield by optimizing the content and molar ratio of an amide-based compound in a polymerization step.

The present disclosure provides 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.

The present disclosure provides 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.