Kinetic simulation of single electron transfer–living radical polymerization of methyl acrylate at 25 °C

Abstract

A mechanistic comparison of the ATRP and SET‐LRP is presented. Subsequently, simulation of kinetic experiments demonstrated that, in the heterolytic outer‐sphere single‐electron transfer process responsible for the SET‐LRP, the activation of the initiator and of the propagating dormant species is faster than of the homolytic inner‐sphere electron‐transfer process responsible for ATRP. In addition, simulation experiments suggested that in both polymerizations the rate of deactivation is similar. In SET‐LRP, the Cu(II)X2/L deactivator is created by the disproportionation of Cu(I)X/L inactive species, while in ATRP its concentration is mediated by the bimolecular termination. The combination of higher rate of activation with the creation of deactivator via disproportionation provides, via SET‐LRP, an ultrafast synthesis of polymers with very narrow molecular weight distribution at room temperature. SET‐LRP is mediated by a catalytic amount of Cu(0), and under suitable conditions, bimolecular termination is virtually absent. Kinetic and simulation experiments have also demonstrated that the amount of water available in commercial solvents and monomers is sufficient to induce the disproportionation of Cu(I)X/L into Cu(0) and Cu(II)X2/L and, subsequently, to change the polymerization mechanism from ATRP to SET‐LRP. © 2006 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem 45: 1835–1847, 2007.

Cu(0)-Mediated Living Radical Polymerization: A Versatile Tool for Materials Synthesis

“…Although Percec and co-workers have demonstrated via kinetic simulations that in the heterolytic OSET process the activation of the initiator and of the propagating dormant species is faster than in an ISET process, 66 Zhong et al showed that the contribution of Cu(0) activation of alkyl halides to the overall polymerization is very small and thus it acts as a supplemental activator. Additional simulations based on experimentally measured rate coefficients showed that Cu(0) can also play the role of reducing agent as it is able to regenerate Cu I Br through comproportionation, and thus it was concluded that the SARA-ATRP mechanism can successfully describe these observations.…”

Copper(0)‐Mediated Living Radical Polymerization of Methyl Methacrylate in a Non‐polar Solvent

“…In this work, we describe the near-room temperature Cu(0)-mediated polymerization of MMA in toluene. As copper(I) complexes have previously been shown not to disproportionate in toluene, [26,27] we propose that this polymerization does not proceed by an OSET/instantaneous disproportionation mechanism. The mechanism of this particular system is under further investigation.…”

Universal Conditions for the Controlled Polymerization of Acrylates, Methacrylates, and Styrene via Cu(0)-RDRP

“…Under these conditions, and in agreement with the literature, >99% conversion in a few hours can be achieved with dispersities as low as 1.06 (Table 3, Entry 1, Figure S32). 35,62,63 However, having a universal set of conditions and reagents that would allow for the controlled polymerization of acrylates, methacrylates and styrene would be advantageous as it enables greater accessibility of polymeric materials by non-experts. As such, we were initially interested to explore whether IPA could afford the controlled polymerization of MA (maintaining EBiB and Me6Tren).…”