DUAL INFLUENCE OF LITHIUM-CHLORIDE ON THE REACTIVITY OF POLYSTYRYLLITHIUM IN ETHEREAL SOLVENTS

Addition of LiCl to ethereal solutions of polystyryllithium retards pr opagation of the polymerization at low polymer concentration, but acce lerates it at higher polymer concentrations. This phenomenon is accoun ted for by the dual action of LiCl. Its dissociation yielding free com mon Li+ ions which diminish the concentration of the reactive free pol ystyryl anions dominates at low electrolyte concentrations. However, a t their higher concentrations the Li+ scavenging action of LiCl, resul ting in the formation of LiClLi+ triple ions, becomes important, it re duces the concentration of the free Li+ ions and increases, therefore, the proportion of the reactive free polystyryl anions.