Production process of poly(arylene sulfide)

A process for producing a poly(arylene sulfide), comprising, after a dehydration step of heating and dehydrating a mixture containing an organic amide solvent, at least one sulfur source (A) selected from the group consisting of alkali metal hydrosulfides and alkali metal sulfides, and an alkali metal hydroxide added as needed to control the amount of water in the mixture, a polymerization step of charging a dihalo-aromatic compound (B) into the system containing the remaining mixture to subject the sulfur source (A) and the dihalo-aromatic compound (B) to a polymerization reaction in the organic amide solvent, which comprises:

• (1) in the dehydration step, (i) heating the mixture containing the organic amide solvent, at least one sulfur source (A) selected from the group consisting of alkali metal hydrosulfides and alkali metal sulfides, and the alkali metal hydroxide added as needed in a reaction vessel, to which a distillation column is linked, and guiding volatilized vapor to the distillation column to distill and separate it into respective components, (ii) refluxing a fraction taken out of the bottom of the distillation column and comprising the organic amide solvent as a principal component into the reaction vessel, (iii) cooling a fraction taken out of the top of the distillation column and comprising water and hydrogen sulfide to discharge hydrogen sulfide that is not condensed by the cooling and reflux a part of water condensed into the distillation column, and (iv) discharging the remaining water, wherein a weight ratio of an amount of water refluxed into the distillation column in step (iii) to an amount of water discharged without being refluxed in step (iv) is within a range of from 90:10 to 10:90,
• (2) calculating an amount of hydrogen sulfide discharged from the reaction vessel on the basis of a relational expression between the total of the amount of water refluxed into the distillation column in step (1)(iii) and the amount of water discharged without being refluxed in step (1)(iv), and the amount of hydrogen sulfide discharged from the reaction vessel, wherein the relational expression is predetermined by regression analysis using experimental data actually measured as to the relation between the total amount of water and the amount of hydrogen sulfide volatilized out in the dehydration step as a database,
• (3) calculating an amount (hereinafter referred to as “amount of the sulfur source charged”) of the sulfur source (A) remaining in the mixture after the dehydration step on the basis of the calculated amount of discharged hydrogen sulfide and controlling a charged molar ratio of the sulfur source (A) to the dihalo-aromatic compound (B) on the basis of the amount of the sulfur source (A) calculated, and then
• (4) subjecting the sulfur source (A) and the dihalo-aromatic compound (B) to the polymerization reaction in the organic amide solvent in the polymerization step.