The Chemistry of Diene Polymerization
VI. Stereospecific Polymerization of Butadiene with Metal Carbonyl Arene Complex
1965 Volume 22 Issue 237 Pages 45-52
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1965 Volume 22 Issue 237 Pages 45-52
The tentative hypothesis proposed in the foregoing paper suggested that metal carbonyltrialkyl alminum should give a polymerization catalyst when an appropriate Lewis acid is added as a third component. From this idea, the following three components catalysts which have improved catalytic activities for 1, 4-cis polymerization of butadiene were found.
Co2 (CO) 8-AlCl3-AlEt3 (1)
[Co2 (CO) 8-AlBr3]-AlEt3 (2)
The components comprized in the bracket was aged at 20°Cfor 2 hrs. Studies on the catalyst (2) lead to finding of an arene cobalt complex catalyst [Co (C6H6) 3 (CO) 2] +Et3Al2Br4-. The role of aromatic solvents in the catalysis was interpreted in terms of entropy effects.
Finally, the most active and the best stereoregulating catalyst system, CoIIX2-AlCl3-AlR3was found by replacing Co2 (CO) 8 in (1) with CoIIX2L2.
