Thiacalix[4]amido-based Netty Polymers:Novel Sorbents for Heavy Metal Cations andDerivatives of Aniline

By reacting p-tert-butylthiacalix[4]arene with ethyl chloroacetate using KI ascatalyst in K2CO3/acetone, 5,11,17,23-tert-butyl-25,26,27-tri-ethoxy-2-acetylthiacalix[4]arene and 5,11,17,23-tert-butyl-25,26,27,28-tetra-ethoxy-2-acetylthiacalix[4]arene were prepared in moderate yields. Their further reactions withbi-(ethyleneimine) or tri-(ethyleneimine) produced the first examples of four tri-bridgedand tetra-bridged thiacalix[4]amido-based polymers with porous and netty architecturesin yields of 81%, 84%, 86%, 89%, respectively. The structures of these polymers wereconfirmed by FTIR, elemental analysis, 1H NMR, and SEM, etc. The Mn of these novelpolymers were 18000~22000 which indicated that approximately 17~20 thiacalix[4]arene units are present in each polymer molecule. The adsorption experiments of thesenovel polymers showed excellent adsorption abilities for soft metal cations Ag+, Hg2+,Cu2+, Co2+, Ni2+, Cd2+, and Zn2+, but low adsorption towards hard metal cations Na+and K+. Also, these novel polymers exhibited outstanding adsorption capacity for aseries of aniline derivatives. The highest adsorption percentages were 93.4% and94.2% for Cu2+ and p-nitroaniline, respectively. The saturation adsorption capacities ofthiacalix[4]amido-based polymer with tri-(ethyleneimine) for Cu2+ and p-nitroanilinewere as high as 1.51 mmol/g and 1.34 mmol/g, respectively. The adsorptionpercentages of novel polymers reduced sharply in pH 4, but they can be recycled bydesorption in 10% ammonia solution.