Premium
Polymerization of 4‐Methyl‐1,3‐pentadiene with Catalysts Based on Cyclopentadienyl Titanium Chlorides: Effect of anti/syn Isomerism of the Allylic Group on the Chemoselectivity and the Role of Backbiting Coordination in 1,3‐Diene Polymerization
Author(s) -
Cugini Cecilia,
Rombolà Ottavio A.,
Giarrusso Antonino,
Porri Lido,
Ricci Giovanni
Publication year - 2005
Publication title -
macromolecular chemistry and physics
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.57
H-Index - 112
eISSN - 1521-3935
pISSN - 1022-1352
DOI - 10.1002/macp.200500135
Subject(s) - chemoselectivity , alkene , chemistry , diene , polymerization , copolymer , polymer chemistry , allylic rearrangement , cyclopentadienyl complex , catalysis , organic chemistry , polymer , natural rubber
Summary: Homopolymerization of 4‐methyl‐1,3‐pentadiene (MP) and copolymerization of 4‐methyl‐1,3‐pentadiene with alkenes (ethylene, 1‐pentene, 4‐methyl‐1‐pentene) were performed to investigate the effect of the so‐called backbiting coordination on the chemoselectivity of 1,3‐diene polymerization. Three homogeneous catalyst systems were used: CpTiCl 3 ‐MAO, Cp 2 TiCl 2 ‐MAO and Cp 2 TiCl‐MAO. Backbiting coordination is possible with the first catalyst, but not with the other two. The three catalysts gave similar results, which indicates that backbiting has no effect on the polymerization chemoselectivity, contrary to what has been reported in recent literature. An interpretation is presented for the formation of 1,4 units in MP/alkene copolymers. This interpretation is based on the fact that allyl groups have predominantly a syn configuration in MP homopolymerization, whereas allyl groups of anti configuration are formed in MP/alkene copolymerization. The role of backbiting in diene polymerization is discussed.The effect of anti/syn isomerism on the chemoselectivity in the different polymerizations.