Reverse ATRP process of acrylonitrile in the presence of ionic liquids

An ionic liquid, 1-butyl-3-methylimidazolium tetrafluoroborate ([C(4)mim] [BF4]), was first used as the solvent in azobisisobutyronitrile (AIBN)-initiated reverse atom transfer radical polymerization (RATRP) of acrylonitrile with FeCl3/succinic acid (SA) as the catalyst system. The polymerization in [C(4)mim][BF4] proceeded in a well-controlled manner as evidenced by kinetic studies. Compared with the polymerization in bulk, the polymerization in [C(4)mim][BF4] not only showed the best control of molecular weight and its distribution but also provided rather rapid reaction rate with the ratio of [C(4)mim][BF4] at 200:1:2:4. The polymerization apparent activation energies in [C(4)mim][BF4] and bulk were calculated to be 48.2 and 55.7 kJ mol(-1), respectively. Polyacrylonitrile obtained was successfully used as a macroinitiator to proceed the chain extension polymerization in [C(4)MiM][BF4] via a conventional ATRP process. [C(4)mim][BF4] and the catalyst system could be easily recycled and reused after simple purification and had no effect on the living nature of polymerization. (c) 2008 Wiley Periodicals, Inc.