Behavior of mixed systems based on para-substituted 4-aroyl-5-pyrazolones in the presence of phosphorus containing calix[4]arene towards lanthanoids: Synergistic solvent extraction and separation

Are fancy acidic or neutral ligands really needed for synergism in ionic liquids? A comparative study of lanthanoid extraction in CHCl3 and an ionic liquid

“…16,17 In particular, some of the authors of this work put a special emphasis on systematically unraveling the relationship between the nature of the para substituents of 4-aroyl-3-methyl-1-phenyl-pyrazol-5-ones and the effectiveness of the extraction process of lanthanoids. 18 Such systematic studies aim at offering additional possibilities to empirically understand the requirements for an efficient extractant. Similarly, the unique molecular architecture of calixarenes (macrocycles made up of n phenolic units linked by methylene bridges) makes them a suitable platform for construction of host neutral molecules that can selectively bind a variety of guest substrates through introduction of suitable fragments on the upper or lower rim.…”

“…[19][20][21] The fascinating conformational and chemical reactivity of the calixarene systems has led to their use in a variety of applications including the development of efficient separation synergistic systems. 18,22 However, depending on molecular solvents and nature of the acidic and neutral components of the synergistic system, either joint increase 9 or opposite trends for extraction and selectivity 18 can be obtained. Nowadays, under the driving forces of the new European chemical regulation REACH (registration, evaluation, authorisation and restriction of chemicals) and of worldwide general ecological concerns, noxious volatile organic compounds (VOCs), such as the molecular solvents traditionally used in liquid/liquid extraction, tend to be banished from any chemical process.…”

Coordination Chemistry of Europium(III) Ion Towards Acylpyrazolone Ligands

“…ii) Formation of self-adduct species LnL3·HL including one unprotonated acidic ligand. 11,14,31 Albinsson has established that in the organic phase (C6H6) at least two complexes exist, LnAa3 and the self-aduct LnAa3·HAa as well as for the lower lanthanoids (especially La) a second self-adduct, LnAa3(HAa)2 was supposed to be extracted with acetylacetone (HAa). 32 The solvent extraction behavior of all 4f-elements has been investigated in aqueous-benzene medium using 3-methyl-1-phenyl-4-benzoyl-5-pyrazolone (HP) and the composition of the species has been determined as LnP3·HP.…”

“…Furthermore, depending on the IL nature, the Tf2N -transfer may be below the detection limits of the NMR technique. 29 Another way that is different from the classical slope analysis 11,14,22,23 to determine the stoichiometry of the extracted species and can give insight into the first coordination sphere, is EXAFS. Distinction between oxygen atoms arising from H2O or Tf2N -or the ligand could be made provided model compounds with known X-ray structure and EXAFS spectra.…”

“…In a fundamental view, this prompted us to synthesize two new europium(III) complexes with different or similar architecture as those formed in solution 11,14 during the liquid-liquid extraction process by applying two acylpyrazolones possessing methyl (+I) or Ph (±M) substituent at the 4-position of the aroyl group. Their structure may be a hint for the determination of the extraction mechanism in ionic liquids (ILs).…”