Production of highly syndiotactic polymers of alpha-alkyl acrylic monomers comprises polymerizing the monomers in the presence of a catalyst formed in situ from a dicyclopentadienyl rare earth metal complex

摘要

Production of (co)polymers of alpha -alkyl acrylic monomers (I) comprises polymerizing (I) in the presence of a catalyst formed in situ from a dicyclopentadienyl rare earth metal complex (II) in an aprotic solvent at a temperature between -100[deg]C and the b.pt. of the solvent. Production of (co)polymers of alpha -alkyl acrylic monomers of formula (I) comprises polymerizing (I) in the presence of a catalyst formed in situ from a rare earth metal complex of formula Cp2LnR6> (II) in an aprotic solvent at a temperature between -100[deg]C and the b.pt. of the solvent; [Image] R1>1-20C alkyl; R2>CSR3> or COR3>; R3>OR4>, SR4> or NR4>R5>; R4>, R5>1-20C alkyl, cycloalkyl, (1-4C)alkyl(1-4C)alkyl, alkylaryl or aryl; Cp : optionally substituted cyclopentadienyl; Ln : tri- or divalent rare earth metal; R6>aluminate or Si-containing amide ligand capable of undergoing agostic interactions, i.e. additional noncovalent coordination to Ln. Independent claims are also included for: (1) a process for a process as above in which the catalyst is formed in situ from a mixture of: a complex of formula (II) in which R6> is an amide ligand capable of undergoing agostic interactions; and a complex of formula (II) in which R6> is an aluminate ligand capable of undergoing agostic interactions; (2) a (co)polymer produced by the process and having a syndiotacticity of more than 40%, based on 1>H-NMR analysis of alpha -methyl groups.