Living polymerization of primary alkyl acrylates with t-butyllithium/bulky aluminum Lewis acids

Anionic polymerizations of primary alkyl acrylates such as ethyl acrylate (EA) and n-butyl acrylate (n-BuA) with tert-butyllithium (t-BuLi) in the presence of bis(2,6-di-tert-butylphenoxy)alkylaluminums were carried out in toluene. The polymerizations with t-BuLi/bis(2,6-di-tert-butylphenoxy)ethylaluminum at low temperatures gave syndiotactic-rich polymers with narrow molecular weight distribution (MWD) in high yields, while those with t-BuLi/bis(2,6-di-tert-butylphenoxy)methylaluminum gave polymers with broader MWD in lower yields. The monomer addition experiment revealed the livingness of the former polymerizations. The initial monomer concentration and polymerization temperature were found to affect the MWD and the stereoregularity of the obtained polymers.