Neodymium versatate

Butadiene has been converted into poly-l,4-(cis-butadiene) in greater than 98.3% by Ziegler-Natta catalysis comprising neodymium versatate, diethyl aluminum chloride, diisobutylaluminum hydride, and triisobutyMuminum. The polymer was then converted into a polybutadiene-polyurethane copolymer by reacting with a diisocyanate and diol. This copolymer exhibited low cold flow and high affinity for silica or carbon black, excellent elasticity, and abrasion resistance. 

The Ziegler-Natta catalyst used for the reaction consisted of 1.0% neodymium versatate dissolved in cyclohexane solution, IM of diethylaluminum chloride... 

Neodymium versatate, triisobutylaluminum, diisobutylaluminum hydride, diethylaluminum chloride, respectively... 

Figure 2. Effect of polymerization temperature (0) and AlR, Nd(vers), molar ratio (O) on molecular weight. Et,Al/ Ndivers), molar ratio was kept at 40 1 when the temperature was varied, and the temperature was maintained at 60°C when Et,Al/Nd(vers), molar ratio was varied. Nd(vers), is the neodymium salt of Versatic 10, which is a mixture of isomeric tertiary carboxylic acids.

According to the number of citations in patents and in scientific literature neodymium(III) carboxylates have found widespread application. These systems were first reported by Monakov et al. in 1977 [152,153]. In 1980 the use of the highly soluble neodymium(III) versatate (NdV) was patented by Bayer [154,155]. At sufficiently low concentrations the most commonly used Nd-carboxylates (Scheme 2) are completely soluble in hydrocarbon solvents. Because of this, Nd-carboxylates are the focus of many studies and are often referred to in the literature. 

Neodymium(III) versatate (NdV), the mixture of isomers of different a,a-disubstituted decanoic acids is also referred to as neodymium neode-canoate. 

Scheme 2 Most commonly used neodymium(III) carboxylates Nd versatate (NdV), Nd octanoate (NdO), Nd isooctanoate (NdzO), Nd naphthenate (NdN)...

Keeping in mind the efficiency of aluminum derivatives as cocatalysts and CTA when associated to lanthanide versatate in conjugated diene polymerization, we investigated the behavior of some Nd-carboxylate-based MOF/aluminoxane catalysts versus isoprene polymerization [33]. At elevated temperatures, the value of initiation efficiency (vs neodymium) appeared far higher than 100%, which suggests the probable occurrence of transfer reactions between Nd and A1 during the polymerization process. It is worth noting that the CM-selectivity remains close to 80% (Scheme 27.7). 

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