Calorimetric Titration of Complexation of the N-benzylmonoaza-18-Crown-6 with Rare Earth(Ⅲ)Nitrates in Anhydrous Acetonitrile  

作　　者：刘育 鲁统部 谭民裕 井上佳久 白子忠男 

机构地区：[1]Department of Chemistry,Nankai University,Tianjin 300071,China [2]Department of Chemistry,Lanzhou University,Lanzhou 730000,China [3]Himeji Institute of Technology,Hyogo,Japan

出　　处：《Journal of Rare Earths》1993年第4期246-251,共6页稀土学报（英文版）

基　　金：Project supported by the National Natural Science Foundation of China;the Director's Fund of Lanzhou Institute of Chemical Physics

摘　　要： Calorimetric titrations were performed in anhydrous acetonitrile at 298.15 K,giving the com-plex stability constants(K_s)and the thermodynamic parameters for the complexation of the rare earth ni-trates(La～Er,Yb)with N-benzylmonoaza-18-crown-6(18-C-6).Thermodynamic quantities clearly in-dicate that the coordination stability of the arm-type 18-crown-6 with the lanthanoid nitrates increasesfrom Ce to Gd,and decreases slightly from Gd to Tb with increasing atomic number.The coordination of thearm-type 18-C-6 with Gd shows the stonger complexation ability and selectivity.Thermodynamically theformation of the complexes is evidently driven by enthalpy,but the complexes stability sequence is essentiallyentropy governed.<正> Calorimetric titrations were performed in anhydrous acetonitrile at 298.15 K,giving the com-plex stability constants(K_s)and the thermodynamic parameters for the complexation of the rare earth ni-trates(La～Er,Yb)with N-benzylmonoaza-18-crown-6(18-C-6).Thermodynamic quantities clearly in-dicate that the coordination stability of the arm-type 18-crown-6 with the lanthanoid nitrates increasesfrom Ce to Gd,and decreases slightly from Gd to Tb with increasing atomic number.The coordination of thearm-type 18-C-6 with Gd shows the stonger complexation ability and selectivity.Thermodynamically theformation of the complexes is evidently driven by enthalpy,but the complexes stability sequence is essentiallyentropy governed.

关 键 词：Crown ether COMPLEXATION Thermodynamics 

分 类 号：TF845-55[冶金工程—有色金属冶金]