Calculation of lithium isotope effects in extraction systems with crown ethers

• Published in: Russian journal of inorganic chemistry Vol. 62; no. 12; pp. 1665 - 1669
• Main Authors: Demin, S. V., Bochkarev, A. V., Tsivadze, A. Yu
• Format: Journal Article
• Language: English
• Published: Moscow Pleiades Publishing 01.12.2017; Springer Nature B.V
• Subjects: Anions; Chemistry; Chemistry and Materials Science; Crown ethers; Ethers; Inorganic Chemistry; Ion concentration; Ions; Lithium; Lithium ions; Mathematical analysis; Physical Chemistry of Solutions; Quantum chemistry; Separation
• ISSN: 0036-0236; 1531-8613
• DOI: 10.1134/S0036023617120075

Complexes of lithium salts with benzo-15-crown-5 and its derivatives have been prepared. Their structure has been established by X-ray diffraction analysis. On the basis of obtained data, the dependence of partition function ratios for isotopic forms (β factors) of these compounds on the type of extracted salt anion and other factors has been analyzed. Taking into account previously calculated value of β factor for aqua complex of lithium ion, single isotope extraction separation factors (α) for Li 6 –Li 7 pair have been determined. Quantum chemical calculations for vibrational frequencies of isotope forms of complexes with crown ethers have been performed with the aid of Firefly (PC GAMESS) software. Lithium cation complexes with crown ethers have been calculated using RHF/6-311++G** basis set. Isotope extraction separation factors have been shown to be independent of lithium ion concentration in aqueous phase and the type of extracted salt anion but depend only on the type and size of crown ether ring.