Equilibrium Constants and Activation Rate Coefficients for Atom Transfer Radical Polymerizations at Pressures up to 2 500 Bar

Equilibrium constants, K ATRP , and activation rate coefficients, k act , have been measured up to 2 500 bar and used for estimating reaction volumes, Δ V R , and activation volumes, Δ V ‡ act , respectively. Quantitative analysis of binary copper‐ligand–alkyl bromide initiator systems, without monomer being present, has been carried out in a solution of acetonitrile by high‐pressure online‐FT‐NIR/VIS spectroscopic monitoring of the Cu II ligand species. The numbers for Δ V R and Δ V ‡ act are close to each other and reflect the characteristics of ligand complexation. Whereas Δ V R is almost insensitive to the type of initiator, the absolute K ATRP clearly depends on this alkyl bromide species. magnified image