Patent ID: 7977437

Claim:
A process for preparing a polydiene, the process comprising the step of: polymerizing conjugated diene monomer with a lanthanide-based catalyst system including the combination of or reaction product of (a) a lanthanide compound, (b) an alkylating agent, (c) a halogen-containing compound, and (d) a dihydrocarbyl ether, where (a) the lanthanide compound, (b) the alkylating agent, (c) the halogen-containing compound, and (d) the dihydrocarbyl ether are introduced directly and individually to the monomer, and where the dihydrocarbyl ether is defined by the formula R—O—R, where each R is independently a hydrocarbyl group or substituted hydrocarbyl group selected from the group consisting of alkyl, cycloalkyl, substituted cycloalkyl, alkenyl, cycloalkenyl groups, and benzyl groups.