Patent ID: 7709580

Claim:
A method for preparing a polyolefin containing one or more exo-olefinic end groups on the polymer chain from a monomer, comprising quenching a cationic quasi-living polyolefin polymer system with one or more nitrogen-containing five-membered aromatic ring compounds selected from pyrroles and imidazoles after high conversion of the monomer has occurred, wherein the pyrroles have the formula: wherein: (a) R 1 and R 2 form a fused aromatic ring of from 6 carbon atoms to 10 carbon atoms or an aliphatic ring of from 4 carbon atoms to about 8 carbon atoms, R 4 is alkyl containing one carbon atom to about 20 carbon atoms, and R 3 is hydrogen or alkyl containing one carbon atom to about 20 carbon atoms, cycloalkyl of about 3 to about 7 carbon atoms, aryl of about 6 to about 30 carbon atoms, alkaryl of about 7 to about 30 carbon atoms, or aralkyl of about 7 to about 30 carbon atoms; or (b) R 2 and R 3 form a fused aromatic ring of from 6 carbon atoms to 10 carbon atoms or an aliphatic ring of from 4 carbon atoms to about 8 carbon atoms, and R 1 and R 4 are independently alkyl containing one carbon atom to about 20 carbon atoms; or (c) both R 1 and R 2 , and R 3 and R 4 , taken in pairs, independently form a fused aromatic ring of from 6 carbon atoms to 10 carbon atoms or an aliphatic ring of from 4 carbon atoms to about 8 carbon atoms; and the imidazoles have at least two hydrocarbyl substituents attached to the aromatic ring, provided the nitrogen containing five-membered aromatic ring is not: (a) 2-phenylindole; (b) 2-methylbenzimidazole; (c) 1,2-dimethylimidazole; (d) 2-phenylimidazole; and (e) 2,4,5-triphenylimidazole.