Anionic polymerization of aldehydes. II. Equilibrium polymerization of chloral

Abstract

Abstract Anionic polymerization of chloral at low temperature was found to be living and an equilibrium between polymerization and depolymerization was reached easily provided that the degree of polymerization of polychloral was not too high. True equilibrium monomer concentration and polymer yields were obtained only when an end‐capping reaction was carried out at the polymerization temperature because the non end‐capped living polymer was depolymerized immediately at room temperature. When the degree of polymerization of polychloral attained a certain critical value, polymerization did not proceed further due to occlusion of living ends and consequently a true equilibrium did not hold. From the temperature dependence of the equilibrium monomer concentration, the changes in enthalpy and entropy as well as the ceiling temperature for the polymerization of chloral in THF were determined as −3.5 kcal/mole, −12 cal/deg. mole and 11°C respectively.