Synthesis of functionalized phenylphosphinic acid resins through Michael reaction and their ion-exchange properties

Novel, functional resins, containing variously substituted phenylphosphinic acid ligands, have been obtained via the Michael reaction. Reaction has be en carried out on phenylphosphinic acid resin crosslinked with 2 wt.% of di vinylbenzene using the following electrophiles: methyl chloroformate, ethyl bromoacetate, ethyl 2-bromopropionate, ethyl acrylate, ethyl methacrylate, acrylonitrile and methacrylonitrile giving the desired products with 60-97 % yield. Resulting resins, having carboxylic acid functionin alpha, beta an d gamma position in respect to the phosphinic group have been used in ion-e xchange/ coordination of Cu(II), Cd(II), Ni(II), Zn(II) and Eu(III) from ni tric acid solutions. It has been found that resins with carboxyl groups in alpha and beta positions display higher divalent metal uptake, when the pH of the solution is above 1.5 and ion exchange is a prevailing process. Resi ns with either carboxyl or nitrile group in the gamma position are less eff ective in metal ion uptake than the parent, phenylphosphinic polymer. In ex periments with Eu(III) uptake from 0.1-1.0 M nitric acid solutions, where r esins are supposed to operate mostly through coordination, none of synthesi zed resins performs better than the phenylphosphinic one. This means that i ntroduction of carboxyl group to the phenylphosphinic acid ligand does not give a synergistic effect in coordination of metal ions. (C) 2000 Elsevier Science B.V. All rights reserved.