CONTROLLED, ELEVATED PRESSURE DEHYDRATION OF POLY(ARYLENE SULFIDE) PREPOLYMERIZATION MIXTURE

Abstract of the Disclosure A method for dehydrating pre-polymerization mixtures in the preparation of poly(arylene sulfide) in which a reaction mixture of a sulfur source and an organic amide are contacted at an essentially constant pressure within a range of about 4 psig to about 40 psig and a first temperature in a range of about 300°F to 400°F to form a complex of the reactants with the mixture subsequently maintained at essentially constant pressure while elevating the temperature to a second temperature at which, at the chosen pressure, essentially all water is removed from the mixture. Other compounds including bases, alkali metal carboxylates, alkali metal carbonates, lithium halides, and lithium borate can be present in the reaction mixture. Preferably the sulfur source is sodium sulfide and the organic amide is N-methylpyrrolidone.