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5691995 
Journal Article 
Butadiene polymerization using neodymium versatate-based catalysts: catalyst optimization and effects of water and excess versatic acid 
Quirk, RP; Kells, AM; Yunlu, K; Cuif, JP 
2000 
1 
Polymer
ISSN: 0032-3861 
41 
15 
5903-5908 
WOS:000086654200042 
The polymerization of 1,3-butadiene (Bd) in a stirred batch reactor with the ternary catalytic system Nd(versatate)3/Al2Et3Cl3/Al(i-Bu)2H in cyclohexane at 70°C has been studied with initial emphasis on the effects of the order of addition of the catalyst components, the concentrations of Al2Et3Cl3 and Al(i-Bu)2H. Using in situ catalyst activation, the optimum concentration ratios of Nd(versatate)3/Al2Et3Cl3/Al(i-Bu)2H=1:1:25 at a catalyst concentration of 0.11mmol Nd/100g Bd was established and used to determine the influence of water and excess versatic acid ([versatic acid]/[Nd]-3) on polymerization performance. It was found that the optimum catalyst characteristics were obtained when [H2O][Nd]=0.11; higher and lower amounts of water decreased conversion, broadened the molecular weight distribution and increased the molecular weight. Increasing the level of excess versatic acid above [excess versatic acid]/Nd]=0.22 resulted in lower conversions, broader molecular weight distributions and higher molecular weights. Polybutadiene cis-1,4 contents were consistently high for all polymerizations (ca. 98%) and were found to be independent of the water content and excess acid level. 
Neodymium versatate; Butadiene