Use of dicyanamide ionic liquids for extraction of metal ions

Abstract

A correlation between the extraction capacity of tetraalkylammonium dicyanamide ILs and the nature of the anion of the metal salt was investigated.

Expanding the Electrochemical Window: New Tunable Aryl Alkyl Ionic Liquids (TAAILs) with Dicyanamide Anions

“…Dicyanamide ILs are generally obtained by the reaction of the chloride or bromide salt with AgN(CN) 2 . To avoid any silver contamination, TAAILs 29 – 40 were synthesized following a modified protocol of Boudesocque and co‐workers . The corresponding bromide salt is suspended in sodium dicyanamide solution in water (1.5 equivalents) and stirred at room temperature for 24 hours.…”

“…[48] Recently,i tw as reported that the dicyanamide (DCA) anion led to remarkable improvements of the viscosity and electrochemicalw indow (EW) of ammonium-,p hosphonium-a nd imidazolium-based ionic liquids leading to be promising candidates for the applications mentioned above. [54][55][56][57] Therefore, we were interested in the combination of the dicyanamide anion with different TAAIL cations and its influence on the physicochemical properties of the resulting materials. To further investigate the structure-property correlation, we synthesized as et of TAAILs with different aryl substituents in the ortho-a nd para-position and differenta lkyl chain lengths (butyl, octyl and dodecyl) with both the DCA anion and the bis(trifluoro-methylsulfonyl)imide (N(SO 2 CF 3 ) 2 ,N Tf 2 )a nion for comparison.…”

Novel Task Specific Ionic Liquids to Remove Heavy Metals from Aqueous Effluents

“…The high extraction properties of Dca − based ionic liquids are ascribed to the ability of dicyanamide anion to interact with metallic cations through the formation of metal complexes via their nitrogen atoms [33,34]. The examination of the structure of metal complexes in which the dicyanamide anion acts as a ligand, shows that this anion behaves as a monodentate or bridging ligand [33,34]. It is reasonable to think that the higher extraction yields observed for Cu(II) and Cd(II) compared to those of Ni(II), Co.(II) and Pb(II) are related to their higher affinity for Dca − anion, which favors their transfer from aqueous to ionic liquid phases.…”

“…Although it has high extraction yields, BuNC 2 OC 2 -Dca does not allow considering applications in the field of the purification of industrial effluents because of its solubility in water (≈6%), that is why we focused on the development of more hydrophobic ionic liquids, to reduce the releasing of organic cations in aqueous phase. The high extraction properties of Dca − based ionic liquids are ascribed to the ability of dicyanamide anion to interact with metallic cations through the formation of metal complexes via their nitrogen atoms [33,34]. The examination of the structure of metal complexes in which the dicyanamide anion acts as a ligand, shows that this anion behaves as a monodentate or bridging ligand [33,34].…”

“…The dicyanamide anion is a cheap anion that is easy to handle to generate ILs. Its chelating ability for metal ions is well known [31,32] and the ability of the Dca − ionic liquids to extract Cu(II) and Ni(II) from water [26,33,34] was shown in a previous study.…”