Investigation of methylaluminoxane as a cocatalyst for the polymerization of 1,3-butadiene to highcis-1,4-polybutadiene

Abstract

The catalytic system Co/methylaluminoxane/tert‐butyl chloride has been studied and optimized for the polymerization of 1,3‐butadiene to high cis‐1,4‐polybutadiene. The ratio of the individual catalyst components was investigated to achieve maximum conversion, stereoregularity, and molecular weight. It was found that the specific order of addition of catalyst components to the feedstock and aging time therein has critical influence in the polymerization reaction. This can be attributed to the rate of chlorinating the aluminoxane and the stability of the active catalyst sites obtained. © 1999 John Wiley & Sons, Inc. J Polym Sci A: Polym Chem 37: 3277–3284, 1999

Synthesis, characterization and butadiene polymerization studies of cobalt(II) complexes bearing bisiminopyridine ligand

“…As a result, a large number of complexes [1,24e34] have been designed to initiate cis-1,4 selective polymerization, such as CoCl 2 /MAO [33], CoCl 2 (PR 3 ) 2 /AlEt 2 Cl [24] and Co(salen) 2 /MAO [29], while some of them are either heterogeneous, leading to slow initiation and gel formation [25e27], or suffering from comparatively low cis-1,4 selectivity [31]. Meanwhile, for some of cobalt catalyst recipes [24,30,33,34], the active species are generated in situ by mixing the components (cobalt compound, donor and activator), therefore, little is known about the structure of precursor and catalystepolymer correlation, hindering mechanism study and catalyst design for screening more efficient candidates. Thus, investigation of new cobalt catalyst that is homogeneous, well-defined, straightforward and high yielding in synthesis, and providing highly cis-1,4 oriented catalysis has still been one of the most fascinating and challenging subjects.…”

Additive Effect of Triphenylphosphine on the Living Polymerization of 1,3‐Butadiene with a Cobalt Dichloride‐Methylaluminoxane Catalytic System

“…Although a number of catalytic systems have been reported to conduct stereospecific polymerization of 1,3-butadiene for cis-1,4, [1][2][3][4][5][6][7][8][9][10][11] trans-1,4, [12,13] syndiotactic-1,2, [14][15][16] atactic-1,2, [17] and isotactic-1,2, [18] polymers, only limited examples are reported for both stereospecific and living polymerization in 1,3-butadiene. [1][2][3][4] In transition metalcatalyzed polymerization, the addition of a Lewis base is sometimes very effective in the control of the activity, the stereospecificity, and the livingness of the system.…”

Effect of tert‐Butyl Chloride on the Isoprene Polymerization with Neodymium Isopropoxide/Diisobutylaluminum Hydride and Neodymium Isopropoxide/Methylaluminoxane Catalysts

“…Recently, a variety of d-orbital transition metal (e.g., Ti, [5][6][7] Co, [6,8] and Ni [9,10] ) catalytic systems and, more importantly, f-orbital lanthanide (Nd [4,6,[11][12][13][14] and Sm [15] ) catalytic systems have been developed for the 1,3-diene polymerization using methylaluminoxane (MAO) and R 3 Al/ borate as cocatalysts. It has turned out that these catalysts show some distinguished features compared with the conventional Ziegler-Natta catalysts activated by R 3 Al.…”

“…However, these catalysts require a large amount of MAO (100-1 000 mole equivalents) as cocatalyst, an expensive agent, and work well in toluene, a more or less toxic solvent. [5][6][7][8][9][10]13,15] On the other hand, with respect to combinations of Nd catalyst and MAO as cocatalyst, the Nd(carboxylate) 3 / MAO catalysts induce 1,3-diene polymerizations, [4,6,11] but the polymers formed have broad MWD. [11] Lathanocene/ MAO catalysts show only very low activity in the polymerization of buta-1,3-diene and isoprene.…”

“…A chlorine source, for instance, tert-butyl chloride (tBuCl), is reported to be capable of modifying the cis-1,4 stereospecificity of Nd(versatate) 3 /MAO [11] and Co-(octanoate) 2 /MAO catalyst [8] in buta-1,3-diene polymerization. Hence, in the present study, we investigated the effect of tBuCl combined with the Nd(OiPr) 3 /MAO catalyst on isoprene polymerization and compared the results with those of the conventional Nd(OiPr) 3 /diisobutylaluminum hydride (Al(iBu) 2 H) catalyst as a control system.…”