AGET ATRP of acrylonitrile with ionic liquids as reaction medium without any additional ligand

Abstract

Atom transfer radical polymerization using activators generated by electron transfer (AGET ATRP) of acrylonitrile (AN) was carried out for the first time in 1-methylimidazolium acetate ([mim][AT]), 1-methylimidazolium propionate([mim][PT]), and 1-methylimidazolium butyrate ([mim][BT]), respectively. The polymerization was approached by using ascorbic acid (VC) as a reducing agent, ethyl 2-bromoisobutyrate (EBiB) as initiator, only FeBr 3 as catalyst without any additional ligand. Kinetic studies showed that both AGET ATRP of AN in the absence of oxygen and in the presence of air proceeded in a well-controlled manner. Under the same conditions, the polymerization in the presence of air provided rather slower reaction rate and showed better control of molecular weight and its distribution than in the absence of oxygen. The sequence of the apparent polymerization rate constants of AGET ATRP of AN in three ionic liquids was k app([mim][AT]) > k app([mim][PT]) > k app([mim][BT]). The living nature of the polymerization was confirmed by chain end analysis and block copolymerization of methyl methacrylate with polyacrylonitrile as macroinitiator. All the three ionic liquids and FeBr 3 could be recycled and reused and had no effect on the living nature of polymerization.