Designing Polymers for Biphasic Liquid/Liquid Separations after Homogeneous Reactions

The phase-selective solubility properties of polymer supports that could be used in thermomorphic and latent biphasic systems useful in synthesis and catalysis were evaluated using polymers tagged with either visible dyes or fluorescent probes. Heptane/DMF, heptane/90% ethanol−water, heptane/ethyl acetate, heptane/ethanol, and heptane/tert-butyl alcohol solvent mixtures were all studied as examples of thermomorphic or latent biphasic systems. A range of polymers including polyisobutylene (PIB), poly(tert-butylstyrene) (PTBS), poly(octadecyl acrylate) (PODA), and poly(octadecyl methacrylate) (PODMA) were tested for hydrophobic phase-selective solubility. The results of these studies are compared to prior work with polar and nonpolar poly(N-alkylacrylamide)s and polystyrene. Together with this prior work, these results show that a wide range of polymers and solvent mixtures can be used for the recycling of soluble polymer-bound catalysts, reagents, and sequestrants using either thermomorphic or latent biphasic separation strategies.