Abstract
Thermodynamic parameters (ΔH 0ex and ΔS 0ex ) for the overall extractions of monovalent metal (Na, K, Rb, and Tl) picrates with benzo-18-crown-6 (B18C6), and those (ΔH 0D,L and ΔS 0D,L ) for the distribution of B18C6 were determined between chloroform and water. All the extracted B18C6 complexes were l:1:1 complexes (B18C6:metal ion: picrate anion). The ΔH 0ex and ΔS 0ex values for all the metals are negative. Every extraction of the metal picrate with B18C6 is completely enthalpy driven. The ΔH 0D,L and ΔS 0D,L values of B18C6 are both positive, and the partition of B18C6 is entirely entropy driven. Enthalpy (ΔH 0ex,ip ) and entropy changes (ΔS 0ex,ip ) for ion-pair extractions of B18C6-metal ion complexes with picrate anions were calculated. All the ΔH 0ex,ip and ΔS 0ex,ip values are negative, and the ion-pair extractions are completely enthalpy driven.
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References and Notes
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Takeda, Y., Iwasaki, T., Kudo, Y. et al. Thermodynamic study of solvent extraction of monovalent metal picrates with benzo-18-crown-6 into chloroform. J Incl Phenom Macrocycl Chem 14, 303–309 (1992). https://doi.org/10.1007/BF01045988
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DOI: https://doi.org/10.1007/BF01045988