Analysis of the Cu(0)-Catalyzed Polymerization of Methyl Acrylate in Disproportionating and Nondisproportionating Solvents

The kinetic and structural analyses of the polymer resulting from the Cu(0)/Me-6-TREN-mediated polymerization of methyl acrylate (MA) initiated with methyl 2-bromopropionate (MBP) in solvents mediating different degrees of disproportionation are reported. Accurate analyses of the polymerization and of the resulting polymer demand a minimum combination of techniques that includes kinetics, GPC, H-1 NMR, and MALDI-TOF both performed before and after chain-end functionalization via thio-bromo "click" chemistry and reinitiation experiments. At [MA](0)/[MBP](0) = 222 the use of the disproportionating solvent DMSO generated first-order kinetics and 97% active chain ends of the polymer at 89% conversion. The less disproportionating solvent MeCN produced two linear first-order kinetics and a decrease of bromine chain-end functionality of the polymer with conversion, yielding 77% active chain ends at 89% conversion. The nondisproportionating solvent toluene, in the presence of TEMPO, produced two linear first-order kinetics with only 50% active chain ends of the polymer at 92% conversion.