| Abstract: | A comparative study was undertaken of the cationic oligomerization/polymerization of the natural propenylbenzene derivatives, anethole, isoeugenol, and isosafrole, together with synthetic o-methoxypropenylbenzene and N,N-dimethyl-p-propenylaniline using boron trifluoride diethyletherate as catalyst. Two (optimum) reaction temperatures were employed, ?12 and ?45°C, and only the (E) isomers of the monomers were studied. The order of reactivity of the monomers was found to be anethole > isoeugenol > isosafrole > o-methoxypronylbenzene as measured by following the rate of loss of monomer by proton magnetic resonance spectrometry at ?12°C. N,N-dimethyl-p-propenylaniline only appeared to form a complex with the catalyst. Low-molecularweight polymeric materials were prepared from anethole, isosafrole, and isoeugenol at ?45°C using the same catalyst while o-methoxypropenylbenzene formed oligomers. Isosafrole was recovered unchanged when treated with the boron trifluoride diethyl etherate initiator system at ?78°C in an attempt to increase the molecular weight of the polyisosafrole. |
