Anionic polymerization of styrene in the presence of pyridine

Abstract

An interesting effect of pyridine on the anionic polymerization of styrene in THF is described. Pyridine forms a complex with living polystyrene and greatly slows the polymerization rate without changing the degree of polymerization. From kinetic and spectroscopic studies, it was clear that there exist two active species in this system and the complex between living polystyrene and pyridine was of the 1:1 type, which itself had a weak ability to grow. The formation constant of the complex K was found to be about 4 × 105 l./mole. The effect of substituted pyridine was also studied and the nature of the complex was discussed.

Synthesis of γ-lactones from easily and accessible reactants catalyzed by Cu–MnOx catalysts

“…By looking closely at the reactivity and material balance data included in table 1 we concluded that, in general, polymerization of styrene was the most important factor responsible for the decrease of selectivity and yields of 1, preventing in most cases the achievement of proper mass balances (Table 1). Indeed, in most experiments the detection by GC-MS of styrene derived oligomers of high molecular weight at long retention times confirmed this experimental observation (Table 1) [18]. Moreover, the reaction mixture turned into a red colour with time.…”