Method for preparation of polyolefins containing exo-olefin chain ends

A method for preparing a polyolefin containing one or more exo-olefinic end groups on the polymer chain, which comprises quenching a polyolefin polymer comprising a tert-chloride chain end with a nitrogen-containing compound in the presence of a Lewis acid;

• wherein the nitrogen-containing compound has the formula:
• wherein:
• (a) R1 and R4 are independently alkyl of 1 to about 20 carbon atoms;
• and R2 and R3 are independently hydrogen, alkyl of 1 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;
• (b) R1 and R2 form a fused aromatic ring of about 6 to about 10 carbon atoms or an aliphatic ring of about 4 to about 8 carbon atoms;
• R4 is alkyl of 1 to about 20 carbon atoms;
• and R3 is hydrogen, alkyl of 1 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;
• (c) R2 and R3 form a fused aromatic ring of about 6 to 10 carbon atoms or an aliphatic ring of about 4 to about 8 carbon atoms;
• and R1 and R4 are independently alkyl of 1 to about 20 carbon atoms;
• or
• (d) both R1 and R2, and R3 and R4, taken in pairs, independently form a fused aromatic ring of about 6 to 10 carbon atoms or an aliphatic ring of about 4 to about 8 carbon atoms;
• or
• wherein the nitrogen-containing compound is an imidazole having at least two hydrocarbyl substituents attached to the aromatic ring;
• provided that the nitrogen-containing compound is not 2-phenylindole, 2-methylbenzimidazole, 1,2-dimethylimidazole;
• 2-phenylimidazole, and 2,4,5-triphenylimidazole.