Process for the removal of lower molecular weight fractions of poly(arylene sulfide) polymers

A method for selectively producing a poly(arylene sulfide) polymer having a desired molecular weight distribution, which method comprises:

• a) contacting a poly(arylene sulfide) polymer comprising a lower molecular weight fraction and a higher molecular weight fraction with a polar organic compound and a promoter selected from the group consisting of alkali metal salts, water and mixtures thereof, wherein said promoter is soluble in said polar organic compound, under conditions sufficient for the formation of a less dense polymer-lean liquid phase comprising a first portion of said lower molecular weight fraction and a more dense polymer-rich liquid phase comprising essentially all of said lower molecular weight fraction and a second portion of said lower molecular weight fraction;
• b) separating the polymer-lean phase from the polymer-rich phase;
• c) repeating steps a) and b) one or more times using the polymer-lean liquid phase produced in step a) , or the polymer-rich liquid phase produced in step a), or each of said phases separately;
• and
• d) recovering said poly(arylene sulfide) polymer having a desired molecular weight distribution from said phase or phases employed in step c).