Configurational double bond selectivity in the epoxidation of hydroxy-terminated polybutadiene with m-chloroperbenzoic acid

Abstract

The selectivity of the three different double bonds (CIS, TRANS and VINYL) of hydroxyterminated polybutadiene regarding epoxidation was evaluated, using m-chloroperbenzoic acid in toluene below room temperature (−10°C, −5°C, 0°C and 5°C). To determine the kinetic constants for the three configuratons (k1,cis = (2,59–0,6) × 10−2 L · mol−1 · min−1; k2, trans = (5,35–0,82) × 10−2 L · mol−1 · min−1; k3, vinyl = (0,97–0,01) × 10−2 L · mol−1 min−1), 1H and 13C NMR was used along with a system of three parallel equations. The activation energy values were also evaluated (Ea, cis = 53,9 kJ · mol−1; Ea, trans = 70,7 kJ · mol−1 and Ea, vinyl = 261,1 kJ · mol−1) for the three double bond types.