Isomer Effects in the Extraction of Metal Ionsfrom Acidic Nitrate Media by Dicyclohexano-18-crown-6^†

Abstract

The extraction of Strontium and potassium from nitric acid by the cis-syn-cis and cis-anti-cis isomers of dicyclohexano-18-crown-6 (DCH18C6) in 1-octanol is examined. Both isomers are shown to extract significant amounts of undissociated nitric acid. This extraction, along with the formation of metal-nitrato and metal-crown ether complexes in the aqueous phase, is shown to be important in determining the efficiency of metal ion extraction by the two isomers. The DCH18C6 isomer yielding the more efficient extraction of potassium or Strontium is shown to depend upon the crown ether concentration and the aqueous nitric acid concentration.

Separation of strontium from yttrium nitrate solutions by solvent extraction with dicyclohexano-18-crown-6

“…5. They are in good agreement with the data obtained by Kumar et al [10], Dietz et al [12], and Horwitz et al [15]. These results confirm that nitric acid is extracted mainly by n-octanol itself, and only a small portion ofHNOs forms a complex with DCH18C6.…”

“…(3)), presumably due to extractant association [13] or due to the formation of Sr Crown complex in an aqueous phase [12]. At concentrations of DCH18C6 greater than 0.1 M, D Sr is essentially constant (if all other conditions are constant) [13].…”

Chromatographic partitioning of cesium by a macroporous silica‐calix[4]arene‐crown supramolecular recognition composite

“…It is known that almost all of the derivatives of the macrocyclic crown ethers such as dicyclohexano-18-crown-6 (DC18C6) and 4,4 0 ,(5 0 )-di(tert-butylcyclohexano)-18-crown-6 (DtBuCH 18C6), etc., are usually able to associate with HNO 3 through hydrogen bonding and form to 1:1 type of the complex. [26][27][28][29] However, the composition and structure of the associated complex of HNO 3 and Calix [4]arene-R14 have not been investigated yet.…”

Crown ethers in radiochemistry. Advances and prospects

“…It is noteworthy that up to 10 molecules of nitric acid per macrocycle can be extracted from the aqueous to the organic phase. 3,8,124,125 The effect of concentration of nitric and picric acids on the extraction of strontium, 87, 102 ± 104, 119 uranium, 105,107,114,126,127 1.25 and 3.0 mol litre 71 , respectively. For the U 6+ ion, the D U increases as the concentration of HNO 3 is increased and reaches a plateau for its concentration of 5 ± 8 mol litre 71 (Refs 105, 114).…”