Copper-Mediated CRP of Methyl Acrylate in the Presence of Metallic Copper: Effect of Ligand Structure on Reaction Kinetics

Abstract

The kinetics of copper-mediated controlled/ living radical polymerization (CRP) of methyl acrylate (MA) in the presence of Cu 0 and two different ligands that form active catalyst complexes with copperTPMA (tris(2-pyridylmethyl)amine) and Me 6 TREN (tris(2-(dimethylamino)ethyl)amine) are compared. The critical difference between the ligands is that TPMA forms a Cu I complex that undergoes essentially no disproportionation in a mixture of MA and dimethyl sulfoxide (DMSO), DMSO/MA (v/v = 1/2), while the complex with Me 6 TREN undergoes disproportionation to a limited extent. Parameters such as the surface area of Cu 0 wire, the concentration of added Cu II X 2 /L, and ligand concentration were examined. Both the Me 6 TREN-and TPMA-based catalysts efficiently controlled the polymerization of MA. The TPMA-based system showed a power law order of 0.47 for the apparent propagation rate constant with the Cu 0 surface area, very similar to the reported value for the Me 6 TREN-based system, which showed a power law of 0.44. These results demonstrate that the polymerization of MA in DMSO in the presence of metallic copper can be explained by a core atom-transfer radical polymerization (ATRP) process in which the Cu 0 acts as a supplemental activator and reducing agent, rather than through the proposed single-electron-transfer living radical polymerization (SET-LRP) mechanism, which requires additional assumptions, such as complete and instantaneous disproportionation of Cu I /L species.

Computer‐Aided Optimization of Conditions for Fast and Controlled ICAR ATRP of n‐Butyl Acrylate

“…In the presence of metallic copper, a so-called supplementary activator and reducing agent (SARA) ATRP or single electron transfer living radical polymerization (SET-LRP) can also be obtained depending on comproportionation or disproportionation being the dominant side reaction path for the involved catalytic species. [58][59][60] In particular for methyl acrylate, Chan et al [61] and Kwak et al [57] have recently successfully combined ARGET ATRP and the use of a copper wire reducing significantly the residual catalyst amount up to 10 ppm for a TCL of ca. 100.…”

A Theoretical Exploration of the Potential of ICAR ATRP for One‐ and Two‐Pot Synthesis of Well‐Defined Diblock Copolymers

“…[3] Consequently, in the last years various modifications have been introduced to overcome these issues, such as the improvement of the ATRP catalyst, [23][24][25] the optimization of the ATRP catalyst removal, [26][27][28] and the development of modified ATRP techniques using low catalyst amounts. [29][30][31][32] The most frequently applied modified ATRP techniques for the promotion of the ATRP process toward industrial application are initiators for continuous activator regeneration (ICAR) ATRP, [29] activators regenerated by electron transfer (ARGET) ATRP, [29,30] electrochemically mediated ATRP (eATRP) [31] and supplementary activator and reducing agent (SARA) ATRP. [32] In ICAR and ARGET ATRP, the activator is (re)generated from the oxygen-stable deactivator by, respectively, a conventional radical initiator (I 2 ) and a reducing agent (Red) while in eATRP an electrode is employed.…”

Iron compounds in controlled radical polymerization: Ferrocenes, (clathro)chelates, and porphyrins

“…However, the range of the applied catalysts has been mainly limited to the expensive copper [1,25,26] and ruthenium [5,7] compounds. At the same time, successful practical implementation of scientific ideas (including the industrial application) requires that the starting components are highly efficient, selective, relatively cheap, stable at storage, non-toxic, and safe during the operation.…”