Synthesis, extraction, and adsorption properties of calix[4]arene-poly(ethylene-glycol) crosslinked polymer

Novel calix[4]arene-poly(ethylene glycol) crosslinked polymer (CCP) has been synthesized by the polycondensation reaction between a p-tert-butylcalix[4]arene derivative and dihydroxyl capped poly(ethylene glycol) (DHPEG, M-n = 1000) catalyzed by neodymium tosylate. The hydrogel, consisted of 66.9% water and 33.1% CCP, can selectively extract aromatic organic molecules from aqueous solution according to the diameter of the guest molecules, which infers that the diameter of the calix[4]arene cavity is about 5.4 angstrom and the conformation of calix[4]arene units altered from cone conformation to 1,3-alternate conformation during the polycondensation reaction. Furthermore, CCP can also adsorb naphthalene from gas phase, showing much higher capacity than active carbon does, which may have some potential applications in the field of separation and environment protection. (C) 2008 Wiley Periodicals, Inc.