Studies on polymerizations initiated by syncatalytic systems based on aluminium organic compounds, 6. Comparison with isobutene polymerizations initiated by ethylaluminium dichloride or aluminium trichloride

Abstract

AbstractThe results of previous studies carried out on the polymerization of isobutene initiated by diethylaluminium halides plus halogens are compared with results obtained with other syncatalytic systems such as diethylaluminium chloride (or triethylaluminium) plus hydrochloric acid (or tert‐butyl chloride), as well as with results obtained with aluminium compounds such as ethylaluminium dichloride or aluminium trichloride which do not require co‐initiators to initiate the polymerization of isobutene. The kinetic data indicate clearly that the polymerization of isobutene initiated by syncatalytic systems is characterized by a relatively slow initiation and by the absence of important termination reactions and of transfer with monomer. In contrast to this, the polymerizations initiated by strong Lewis acids such as ethylaluminium dichloride or aluminium trichloride show a much faster initiation and stop at incomplete conversion which indicates that at least one efficient termination reaction is operative. It is also demonstrated that this termination reaction produces at least one substance which acts as a co‐initiator for the isobutene polymerization initiated by diethylaluminium halides or triethylaluminium.