Collect. Czech. Chem. Commun. 1983, 48, 3041-3049

Stability of tetramer α-methylstyrene dianion in tetrahydrofuran

Zdeněk Salajka and Miloslav Kučera

Chemopetrol, Special Purpose Organisation Research Institute of Macromolecular Chemistry, 656 49 Brno


Solutions of carbanions of living α-methylstyrene tetramer in tetrahydrofuran exhibit limited stability even at relatively low temperatures. The rate of decay of these active centers depends upon the type of counter-ion and it decreases in the sequence Li+ < Na+ < K+. It is dependent also upon temperature, concentration and some other unrevealed factors. In dark, with Na+ as a counter-ion at 263 K and ~ C-Na+ concentration of 1.5 mmol/dm3, the initial period of a fast concentration decrease of active centers is followed by a very slow period of rate decay. At 296 K the decrease of their concentration is much faster and seems to obey a first reaction order. Rinsing the dry inner surface of glass apparatus by solutions of carbanions does not cause a decrease of their concentration. When a part of the glass apparatus is heated up to the softening point, a certain portion of carbanions is consumed.