Homogenous neodymium neodecanoate/modified methylaluminoxane/diisobutylaluminium hydride catalyst for 1,3-butadiene polymerization

摘要

The neodymium neodecanoate [Nd(neod)3] catalyst activated by modified methylaluminoxane (MMAO) is homogeneous in 1,3-butadiene polymerization in hexane, while the polymer yield was low and a high amount of MMAO ([Al]/[Nd] ≥40) was consumed. When both diisobutylaluminium hydride [Al(i-Bu)_2H] and MMAO were used as cocatalyst, highly effective catalyst was formed at low MMAO level of [Al]/[Nd]=20, while the cis-1,4 content ( < 90%) of polymer was slightly low. The addition of chlorine source such as diisobutylaluminium chloride (Al(i-Bu)_2Cl) improved the cis-1,4 contents of polymer up to 98%, while the molecular weight distribution was rather broad (M_w/M_n > 3.0). The catalyst composed of Nd(neod)_3, MMAO, Al(i-Bu)_2H and Al(i-Bu)_2Cl prepared in the presence of 1,3-butadiene ([BD]/[Nd]=10) was homogeneous and highly effective in 1,3-butadiene polymerization at a relatively low MMAO level ([Al]/Nd=10), to afford a polymer featuring narrow molecular weight distribution (M_w/M_n < 2.0) and high cis-1,4 regularity ( > 97%).