Stereoselective partitioning of organic substrates by thermoresponsive polymers in aqueous phases


Correspondence to: M. Ishifune (E-mail:


Partitioning of organic substrates by thermoresponsive polymer having N-acryloylaminoalcohol moieties in aqueous phase has been studied. Thermoresponsive polymers, such as poly(N-isopropylacrylamide) (PNIPAAm) and poly(NIPAAm-co-N-acryloyl-(±)-alaninol) (poly(NIPAAm-co-HIPAAm)), were found to concentrate several organic substrates into the hydrophobic field generated during their phase transition. The amount of the substrates recoverd from the polymer phase mainly depended on the hydrophobicity of the substrates. Aqueous solutions of PNIPAAm (lower critical solution temperature, LCST = 33°C) and poly(NIPAAm-co-HIPAAm) (LSCT = 41°C) containing 1-phenylethanol showed LCSTs at 22°C and 33°C, respectively. The changes of LCSTs indicate that specific interactions such as hydrogen bonding between the side chain functionalities of the polymers and the substrates influence the phase transition behavior. Moreover, new optically active polymers having chiral aminoalcohol moieties have been synthesized by copolymerizations of NIPAAm with N-acryloylaminoalcohols such as N-acryloyl-(S)-alaninol and N-acryloyl-(S)-prolinol. The (R)/(S) ratio of 1-phenylethanol recovered from poly(NIPAAm-co-N-acryloyl-(S)-alaninol) and poly(NIPAAm-co-N-acryloyl-(S)-prolinol) were determined to be 75/25 and 68/32, respectively. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 130: 3458–3464, 2013