CONFIGURATIONAL DOUBLE-BOND SELECTIVITY IN THE EPOXIDATION OF HYDROXY-TERMINATED POLYBUTADIENE WITH M-CHLOROPERBENZOIC ACID

The selectivity of the three different double bonds (CIS, TRANS and VI NYL) of hydroxyterminated polybutadiene regarding epoxidation was eval uated, using m-chloroperbenzoic acid in toluene below room temperature (- 10-degrees-C, -5-degrees-C, 0-degree-C and 5-degrees-C). To determ ine the kinetic constants for the three configurations (k1, cis = (2,5 9-0,6) x 10(-2) L . mol-1 . min-1; k2, trans = (5,35-0,82) x 10(-2) L . mol-1 . min-1; k3, vinyl = (0,97-0,01) x 10(-2) L . mol-1 . min-1), H-1 and C-13 NMR was used along with a system of three parallel equati ons. The activation energy values were also evaluated (E(a, cis) = 53, 9 kJ . mol-1; E(a, trans) = 70,7 kJ . mol-1 and E(a, vinyl) = 261,1 kJ . mol-1) for the three double bond types.