Polymerization of acrylonitrile catalyzed by single yttrium tris(2,6-di-tert-butyl-4-methyl phenolate)

Polymerization of acrylonitrile was carried out using yttrium tris(2,6-di-tert-butyl 4-methyl-phenolate) (Y(OAr)(3)) as single component catalyst for the first time. The effects of concentrations of the monomer and catalyst, kinds of rare earth element and solvent, as well as temperature and polymerization time were investigated. The overall activation energy of polymerization in n-hexane and THF mixture is 18.3 kJ mol(-1). Polyacrylonitriles (PANs) obtained by using Y(OAr)(3) in n-hexane and THF mixture at 50degreesC are predominantly atactic, while yellow PANs obtained in DMF under the same conditions have a syndiotactic-rich configuration (>50%), and their highly branched and/or cyclized structures have also been found. (C) 2002 Society of Chemical Industry.