title: Assessing the RAFT equilibrium constant via model systems: an EPR study.
abstract: Reversible addition-fragmentation chain transfer (RAFT) equilibrium constants, K(eq), for the model system cyano-iso-propyl dithiobenzoate (CPDB) - cyano-iso-propyl radical (CIP) have been deduced via electron paramagnetic resonance (EPR) spectroscopy. The CIP species is produced by thermal decomposition of azobis-iso-butyronitrile (AIBN). In solution of toluene at 70 °C, K(eq) has been determined to be (9 ± 1) L · mol(-1). Measurement of K(eq) = k(ad)/k(β) between 60 and 100 °C yields ΔE(a) = (-28 ± 4) kJ · mol(-1) as the difference in the activation energies of k(ad) and k(β). The data measured on the model system are indicative of fast fragmentation of the intermediate radical produced by addition of CIP to CPDB.
authors: Institut für Physikalische Chemie, Georg-August-Universität Göttingen, Germany.
authors: Wibke
authors: W
authors: Meiser
authors: Michael
authors: M
authors: Buback
mesh_terms: D007700:Kinetics; D008956:Models, Chemical; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry
chemical_list: D011108:Polymers