Effects of Side-Chain Substituents in Benzo-15-Crown-5 on Lithium Extraction

Abstract

Chloroform–water extraction systems have been studied using crown-ethers as extracting agents, namely: benzo-15-crown-5 (B15C5), 2,3-naphtho-15-crown-5 (N15C5), 4′-nitro-benzo-15-crown-5 (NO₂B15C5), 4′-tert-butyl-benzo-15-crown-5 (TBB15C5), and 4′-acetyl-benzo-15-crown-5 (AcB15C5). Extraction isotherms of these systems have been obtained, and an attempt made to elucidate the effect of the structure of extracting agent on extraction characteristics. IR-spectroscopic studies have been performed for selected crown-ethers and their complexes in crystalline form and in chloroform solutions, namely, for N15C5, NO₂B15C5, AcB15C5, and B15C5. The complexes LiN15C5H₂OClO₄ (1), LiN15C5H₂OI (2), LiNO₂B15C5H₂OI (3), LiAcB15C5H₂OI (4), and LiTBB15C5H₂OI (5) have been isolated for the first time and characterized by IR spectroscopy. Single-crystal X-ray data have been obtained for complexes 1–3.