A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

Provided is a method for producing an organic tellurium compound that enables the production of an organic tellurium compound in high yield using metallic tellurium as a source material and produces less amount of side products. A method for producing an organic tellurium compound includes the steps of: (A) reacting metallic tellurium with a compound represented by a general formula (1) below; and (B) reacting a compound obtained by the step (A) with an organic halogen compound, the metallic tellurium having a copper content of less than 100 ppm,
M(R.sup.1)m   Formula (1)
where R.sup.1 represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, M represents an alkali metal or an alkaline earth metal, m represents 1 when M is an alkali metal, and m represents 2 when M is an alkaline earth metal.

Provided is a method for producing an organic tellurium compound that enables the production of an organic tellurium compound in high yield using metallic tellurium as a source material and produces less amount of side products. A method for producing an organic tellurium compound includes the steps of: (A) reacting metallic tellurium with a compound represented by a general formula (1) below; and (B) reacting a compound obtained by the step (A) with an organic halogen compound, the metallic tellurium having a copper content of less than 100 ppm,
M(R.sup.1)m   Formula (1)
where R.sup.1 represents an alkyl group having 1 to 8 carbon atoms, an aryl group or an aromatic heterocyclic group, M represents an alkali metal or an alkaline earth metal, m represents 1 when M is an alkali metal, and m represents 2 when M is an alkaline earth metal.

The invention provides a process for separating hydrogen from a gaseous feed stream in a polymerisation process, comprising the steps i) polymerising an olefin monomer and optionally at least one olefin comonomer, in the presence of a solvent optionally in the presence of hydrogen, so as to form a polymerisation reaction mixture comprising a polyolefin polymer, unreacted monomer(s), solvent and hydrogen; ii) separating said polyolefin polymer from said unreacted monomer(s), solvent and hydrogen; iii) feeding said unreacted monomer(s) and hydrogen to a condenser so as to form said gaseous feed stream; iv) contacting said gaseous feed stream with a hydrogen separating membrane so as to form a hydrogen-rich gaseous stream and a hydrogen-lean gaseous stream.

The invention provides a process for separating hydrogen from a gaseous feed stream in a polymerisation process, comprising the steps i) polymerising an olefin monomer and optionally at least one olefin comonomer, in the presence of a solvent optionally in the presence of hydrogen, so as to form a polymerisation reaction mixture comprising a polyolefin polymer, unreacted monomer(s), solvent and hydrogen; ii) separating said polyolefin polymer from said unreacted monomer(s), solvent and hydrogen; iii) feeding said unreacted monomer(s) and hydrogen to a condenser so as to form said gaseous feed stream; iv) contacting said gaseous feed stream with a hydrogen separating membrane so as to form a hydrogen-rich gaseous stream and a hydrogen-lean gaseous stream.

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

A method for preparing cis-1,4-polydienes, the method comprising the steps of preparing a preformed, active lanthanide-based catalyst, aging the active lanthanide-based catalyst for more than 5 days to thereby formed an aged catalyst, and introducing the aged catalyst and conjugated diene monomer to be polymerized to thereby form an active polymerization mixture in which the conjugated diene monomer is polymerized to form a polydiene having a reactive chain end.

The present invention relates to a ligand compound, a catalyst system for olefin oligomerization, and a method for olefin oligomerization using the same. The present ligand compound is a compound having a certain new structure and enables provision of a catalyst system for olefin oligomerization that can oligomerize ethylene with higher catalytic activity.

The present invention relates to a ligand compound, a catalyst system for olefin oligomerization, and a method for olefin oligomerization using the same. The present ligand compound is a compound having a certain new structure and enables provision of a catalyst system for olefin oligomerization that can oligomerize ethylene with higher catalytic activity.