LIVING OLIGOMERIZATION OF ISOBUTYLENE INITIATED BY CUMYL CHLORIDE BCL3 MIXTURES - KINETIC-ANALYSIS OF THE INITIATION AND THE EARLY PROPAGATION STEPS

The living oligomerization of isobutylene initiated by cumyl chloride 1 or by the telechelics P1 or P2 in presence of BCl3 and benzyltriethy lammonium tetrachloroborate has been investigated. The tertiary chlori des P2-P7 were separated by HPLC and analyzed as spectroscopically pur e compounds. A kinetic model has been derived from which the gross pro pagation rate constants for the early propagation steps can be calcula ted. It has been found that the low reactivity of the adduct of cumyl chloride to one isobutylene unit (Pi) is responsible for the broad MWD in the cumyl chloride/BCl3/BCl4--initiated oligomerization of isobuty lene. In contrast, a narrow MWD could be achieved by using the 2:1 pro duct P2 in combination with BCl3/BCl4- as initiator.