Novel Methylaluminoxane‐Activated Neodymium Isopropoxide Catalysts for 1,3‐Butadiene Polymerization and 1,3‐Butadiene/Isoprene Copolymerization

Abstract

The homo‐ and copolymerizations of 1,3‐butadiene and isoprene are examined by using neodymium isopropoxide [Nd(Oi‐Pr)3] as a catalyst, in combination with a methylaluminoxane (MAO) cocatalyst. In the homopolymerization of 1,3‐butadiene, the binary Nd(Oi‐Pr)3/MAO catalyst works quite effectively, to afford polymers with high molecular weight (M‾n ≈ 105 g mol‐1), narrow molecular‐weight distribution (MWD) (M‾w/M‾n = 1.4–1.6), and cis‐1,4‐rich structure (87–96%). Ternary catalysts that further contain chlorine sources enhance both catalytic activity and cis‐1,4 selectivity. In the copolymerization of 1,3‐butadiene and isoprene, the copolymers feature high M‾n, unimodal gel‐permeation chromatography (GPC) profiles, and narrow MWD. Most importantly, the ternary Nd(Oi‐Pr)3/MAO/t‐BuCl catalyst affords a copolymer with high cis‐1,4 content in both monomer units (>95%).

The Influence of co-catalyst in the Polymerization of 1,3-butadiene Catalyzed by Neodymium Chloride Tripentanolate

“…These differences between the catalytic activities imply a significant difference in availability of active centers able to initiate the polymerization, which seems to be governed by the different alkylating capacity of the organoaluminum species [14]. The very low catalytic activity observed with MAO as co-catalyst could be attributed to a possible coordination of the alcohol ligand to MAO which led to destabilization of the active site, as it has been reported before for other catalyst systems activated also by MAO [15,16]. It is also noteworthy that the trend of catalytic activity behaved inversely proportional to the bulkiness of the substituents in the co-catalyst, being TEA which led to the highest catalytic activity, substituted by simple ethyl groups.…”

Polymerization of 1,3-butadiene with neodymium chloride tripentanolate/triisobutylaluminum binary catalyst system: effect of aging time and reaction temperature

“…Recently, the polymerization of butadiene employing a binary catalyst system consisting of Nd isopropoxide/ methylaluminoxane [Nd (Oi-Pr) 3 /MAO] was evaluated; this catalyst system was observed to produce the highest cis-1,4 content of 95% when the polymerization was carried out at 30°C, while at 60°C the cis-1,4 content was 86.9% [11].…”

Methylaluminoxane‐activated neodymium chloride tributylphosphate catalyst for isoprene polymerization

“…Visseaux et al reported that a common and unsophisticated compound [Nd(2,6‐di‐ tert ‐butyl‐OC 6 H 3 ) 3 ] in combination with methylaluminoxane (MAO) or modified MAO (MMAO) in the absence/presence of Et 2 AlCl are efficient systems to afford polyisoprene with narrow MWD ( M w / M n ∼ 1.6), albeit with low stereoregularity . Recently, we found that the commercially available Nd(O i ‐Pr) 3 /MAO catalyst works effectively in the homo‐ and copolymerization of 1,3‐butadiene and isoprene, affording high cis ‐1,4 (co)polymers with narrow MWD ( M w / M n < 2.0) and that further addition of chlorine sources enhances both cis ‐1,4 selectivity and catalytic activity …”