Solvent Extraction of Perrhenate with 25,26,27,28-Tetrakis[(ethoxycarbonyl)methoxy]-p- tert-Butylcalix[4]arene and Crystal Structure of the Extracted Complex

The extraction of perrhenate with 25,26,27,28-tetrakis(ethoxycarbonyl)methoxy]-p-tert-butylcali x4]arene ( L) into 1,2-dichloroethane was investigated. The presence of Na+ in the aqueous phase is necessary for the extraction. The extraction equilibrium has been established and the thermodynamic quantities H°, TS° and log Kex are -61.3 kJ/mol, -41.4 kJ/mol and 3.69, respectively. The effect of diverse ions on the extraction of ReO4- was studied. The corresponding extracted complex Na L]ReO4...H2O was prepared and characterized by EA, IR and X-ray structure analysis. The complex crystallizes in the tetragonal space group P4ncc with a = b = 14.735(3), c = 29.094(3) Å, V = 6316(2) Å3, Z = 4.