Continuous reaction for preparation of arylene sulfide polymer

A continuous process using a plurality of agitated reaction vessels connected in series for producing arylene sulfide polymer by contacting, in an organic amide, a dihalo aromatic compound with a suitable sulfur source to produce a particulate, polymeric product, said method comprising:

• a. introducing the reactants into a first reaction zone maintained at substantially liquid-full conditions at a temperature in the range of about 260.degree. C to about 310.degree. C suitable to initiate a polymerization reaction thereby providing a polymerization reaction pressure sufficient to drive the reaction mass through a series of reaction zones;
• b. passing reactants and polymerization product from said first reaction zone into a second, substantially liquid-full reaction zone maintained at a polymerization temperature said temperature in the range of about 5.degree. C to about 25.degree. C lower than the temperature of said first zone and a pressure in the range of about 0.5 Kg/cm.sup.2 to about 2 Kg/cm.sup.2 lower than the pressure in said first zone;
• c. passing partially polymerized reactants and polymerization product from said second reaction zone into a third reaction zone maintained at a polymerization temperature in the range of about 5.degree. C to about 25.degree. C lower than said second reaction zone and a pressure in the range of about 0.5 Kg/cm.sup.2 to about 2 Kg/cm.sup.2 lower than the pressure in said second zone;
• d. passing the effluent from said third reaction zone into a fourth zone having a vapor space above a controlled liquid level wherein the pressure is in the range of about 0.5 Kg/cm.sup.2 to about 2 Kg/cm.sup.2 lower than in the third zone and wherein the temperature is increased to exceed the temperature of said second reaction zone sufficiently to evaporate a portion of the water and organic amide content of the effluent;
• and
• e. subjecting the reaction mixture from the fourth reaction zone to reduced pressure thereby flash evaporating the liquid portion to recover a polymeric, particulate product and a vapor.