Copper catalyzed ATRP of methyl methacrylate using aliphatic α-bromo ketone initiator

Abstract

The atom transfer radical polymerization (ATRP) of MMA was examined using 3-bromo-3-methyl-butanone-2 (MBB) as an initiator in the presence of CuBr as catalyst and 2,6-bis[1-(2,6-diisopropylphenylimino)ethyl]pyridine (BPIEP) as a tridentate N-donor ligand. The effect of various other N-donor ligands including a bisoxazoline ligand, namely, 2,6-bis(4,4-dimethyl-2-oxazolin-2-yl) pyridine (dmPYBOX) was studied in ATRP and reverse ATRP of MMA. The ATRP of MMA in toluene at 90 °C using MBB as initiator was relatively slow in the case of bidentate and faster in the case of tridentate N-donor ligands. The apparent rate constant, k_app, with MBB as initiator and BPIEP as ligand in toluene (50%, v/v) at 90 °C was found to be 7.15 × 10⁻⁵ s⁻¹. In addition, reverse ATRP of MMA in diphenylether at 70 °C using BPIEP/CuBr₂ as catalyst system was very effective in reducing the reaction time from several hours to 24 h for polymerization of MMA.