The applicability of a deep eutectic solvent (DES) consisting of betainium hydrochloride, urea and glycerol is examined with respect to ionometallurgical metal extraction and compared with the ionic ...liquid (IL) betainium bis(trifluoromethylsulfonyl)imide (HbetNTf2). The DES dissolves numerous metal oxides, where not only betaine and chloride act as stabilizing ligands, but also nascent ammonia seems to be essential. From such solutions, cobalt, copper, zinc, tin, lead, and even vanadium can be electrodeposited, demonstrating the feasibility of ionometallurgy. However, repeated recycling of the DES is not conceivable. NMR spectroscopy and mass spectrometry identify numerous decomposition reactions taking place at 60 °C already. The by‐products that are formed not only make recycling more difficult, but also pose a toxicity problem. The opportunities and obstacles of DESs and ILs for their application in ionometallurgy are critically discussed. It is shown that a thorough understanding of the underlying chemical processes is critical.
The applicability of a deep eutectic solvent (DES), formed by betainium hydrochloride, urea and glycerol, for ionometallurgical metal production is investigated and critically discussed. Although several metals can be electrodeposited after rapid dissolution of the respective metal oxide, various decomposition reactions prevent the solvent from being usable and environmentally friendly.
Bi2S3 was dissolved in the presence of either AuCl/PtCl2 or AgCl in the ionic liquids BMImCl ⋅ xAlCl3 (BMIm=1‐n‐butyl‐3‐methylimidazolium; x=4–4.3) through annealing the mixtures at 180 or 200 °C. ...Upon cooling to room temperature, orange, air‐sensitive crystals of BMIm(Bi4S4)AlCl45 (1) or Ag(Bi7S8)S(AlCl3)32AlCl42 (2) precipitated, respectively. 1 did not form in the absence of AuCl/PtCl2, suggesting an essential role of the metal cations. X‐ray diffraction on single‐crystals of 1 revealed a monoclinic crystal structure that contains (Bi4S4)4+ heterocubanes and AlCl4− tetrahedra as well as BMIm+ cations. The intercalation of the ionic liquid was confirmed via solid state NMR spectroscopy, revealing unusual coupling behavior. The crystal structure of 2 consists of (Bi7S8)5+ spiro‐dicubanes, S(AlCl3)32− tetrahedra triples, isolated AlCl4− tetrahedra, and heavily disordered silver(I) cations. No cation ordering took place in 2 upon slow cooling to 100 K.
Two new compounds containing sulfidobismuth cubane or spiro‐dicubane cations were obtained from metal assisted ionothermal syntheses. Fine‐tuning of the composition of the reaction mixture including the ionic liquid proved to be essential for successful syntheses.
The low temperature syntheses of AuTe2 and Ag2Te starting from the elements were investigated in the ionic liquids (ILs) BMImX and P66614Z (BMIm+=1‐butyl‐3‐methylimidazolium; X = Cl, HSO4−, P66614+ = ...trihexyltetradecylphosphonium; Z = Cl−, Br−, dicyanamide DCA−, bis(trifluoromethylsulfonyl)imide NTf2−, decanoate dec−, acetate OAc−, bis(2,4,4‐trimethylpentyl)phosphinate BTMP−). Powder X‐ray diffraction, scanning electron microscopy, and energy‐dispersive X‐ray spectroscopy revealed that P66614Cl is the most promising candidate for the single phase synthesis of AuTe2 at 200 °C. Ag2Te was obtained using the same ILs by reducing the temperature in the flask to 60 °C. Even at room temperature, quantitative yield was achieved by using either 2 mol % of P66614Cl in dichloromethane or a planetary ball mill. Diffusion experiments, 31P and 125Te‐NMR, and mass spectroscopy revealed one of the reaction mechanisms at 60 °C. Catalytic amounts of alkylphosphanes in commercial P66614Cl activate tellurium and form soluble phosphane tellurides, which react on the metal surface to solid telluride and the initial phosphane. In addition, a convenient method for the purification of P66614Cl was developed.
Ag2Te and AuTe2 were obtained from the elements in the ionic liquid P66614Cl at room temperature. The reaction is driven by a dissolved tellurium species that reacts with the noble metal. In commercial P66614Cl, tellurium is reduced by trialkylphosphane impurities. A purification protocol was developed to suspend the influence of the trialkylphosphane. In the purified medium, a different tellurium species appears.
Invited for this month's cover is the group of Michael Ruck at the Technische Universität Dresden (Germany). The cover picture shows the spiro‐dicubane Bi7S85+ in the center, accompanied by two ...Bi4S44+ hetero‐cubanes on both sides, which are shown along their threefold axis. These sulfidobismuth polycations were isolated in salts with AlCl4– and S(AlCl3)32– anions. The starting material was Bi2S3, which is generally hard to dissolve but can easily be activated under ionothermal conditions. Moreover, the presence of noble metal ions, such as Ag+, Au+ or Pt2+, played a crucial role for the formation of those compounds. This research was performed in the framework of the Priority Program SPP 1708 “Material Synthesis Near Room Temperature” of the German Research Council (DFG). Read the full text of their Full Paper at
10.1002/open.202000246.
“…This study emphasizes the importance of various reaction parameters on the outcome of syntheses in ionic liquids…” Find out more about the story behind the front cover research at 10.1002/open.202000246.
Wide applications of anhydrous rare‐earth (RE) trichlorides RECl3 in organometallic chemistry, for the synthesis of optical and magnetic materials, and as catalysts require a facile approach for ...their synthesis. The known methods use or produce toxic substances, are complicated and have limited reliability and upscaling. It has been shown that task‐specific ionic liquids (ILs) can dissolve many metal oxides without special reaction conditions at moderate temperature, making the metals accessible to downstream chemistry. Using imidazolium chloridoaluminate ILs, pure crystalline anhydrous RECl3 (RE=La−Nd, Sm−Dy) can be synthesized in one step from RE oxides in high yield. The Lewis acidic IL acts as solvent and reaction partner. The by‐product Al4O2Cl102−, which was detected spectroscopically, remains in solution. The reacted IL can be removed quantitatively by washing. ILs with various imidazolium cations and AlCl3 content and the effect of temperature and reaction time were tested.
Anhydrous rare‐earth trichlorides RECl3 with high purity and yield are obtained by reacting rare‐earth oxides RE2O3 with aluminum chloride AlCl3 containing ionic liquids at 175 °C. The easy‐to‐perform process provides a reliable and scalable alternative to the production of these difficult‐to‐access anhydrous chlorides. In contrast to previous approaches, neither high temperatures nor highly toxic substances are required.
Owing to the environmental problems of numerous metal production processes, there is a growing need for more energy‐efficient approaches. Cobalt is considered a strategic element that is extracted ...not only from ores but also from spent Li‐ion batteries. One promising new approach is ionometallurgy, which is the extraction of metal oxides by ionic liquids (ILs). This study concerns new investigations into ionometallurgical processing of CoO, Co3O4, and LiCoO2 in the IL betainium bis(trifluoromethylsulfonyl)imide, HbetNTf2. Three crystal structures of cobalt−betaine complex compounds and combined spectroscopic and diffraction studies provide insights into the dissolution process. In addition, an optimized dissolution procedure for metal oxides is presented, avoiding the previously reported decomposition of the IL. Subsequent cobalt electrodeposition is only possible from cationic complex species, highlighting the importance of a thorough understanding of the complex equilibria. The presented method is also compared to other recently reported approaches.
The cobalt oxides CoO, Co3O4 and LiCoO2 are dissolved in the ionic liquid HbetNTf2, whereupon cobalt can directly be electrodeposited. A special focus is on understanding the complex equilibria present in solution and ways to manipulate them specifically. This is relevant for cobalt production from naturally occurring ores and lithium‐ion battery recycling.
The Cover Feature symbolizes the recovery of cobalt metal from battery materials. Cobalt oxides are dissolved in an ionic liquid to form cobalt complexes, and the metal is electrodeposited directly ...from this solution. More information can be found in the Research Article by J. Richter et al.
Zinc electrodeposition is currently a hot topic because of its widespread use in rechargeable zinc‐air batteries. However, Zn deposition has received little attention in organic solvents with much ...higher ionic conductivity and current efficiency. In this study, a Zn‐betaine complex is synthesized by using ZnO and betainium bis(trifluoromethyl)sulfonylimide and its electrochemical behavior for six organic solvents and electrodeposited morphology are studied. Acetonitrile allowed dendrite‐free Zn electrodeposition at room temperature with current efficiencies of up to 86 %. From acetonitrile solutions in which Zn, Pb, and Cu complexes are dissolved in high concentrations, Zn and Pb/Cu are efficiently separated electrolytically under potentiostatic control, allowing the purification of solutions prepared directly from natural ores. Additionally, a highly flexible Zn anode with excellent kinetics is obtained by using a carbon fabric substrate. A rechargeable zinc‐air battery with these electrodes shows an open‐circuit voltage of 1.63 V, is stable for at least 75 cycles at 0.5 mA cm−2 or 33 cycles at 20 mA cm−2, and allows intermediate cycling at 100 mA cm−2.
That zinc‐ing feeling: Electrodeposition in organic solvents allows efficient separation of Zn from Pb and Cu in concentrated solutions of their betaine complexes. This method is used to prepare Zn‐coated carbon‐fabric electrodes that exhibit superior kinetics and inhibition of dendrite formation. A rechargeable zinc‐air battery with this anode has an open‐circuit voltage of 1.63 V and excellent cycling stability and rate performance.
"Spumella"-like flagellates describes similar or even indiscernible colourless non-scaled chrysophytes which are important bacterivores common in different aquatic ecosystems. Recently, phylogenetic ...analyses revealed a high taxonomic diversity of these flagellates leading to the description of several new genera and species. Our present work on the functional group of pelagic bacterivorous chrysomonads from different water bodies resulted in an extended taxonomic analysis among chrysophytes unveiling yet undescribed genera and species pointing to the high hidden diversity of bacterivores in the pelagial of freshwaters. On the basis of phylogenetic analyses, we describe four new genera Atacamaspumella, Chlorospumella, Pseudapoikia, and Vivaspumella and a new species of the recently described genus Poteriospumella. Beside this, we redescribe the species Ochromonas vasocystis Doflein, 1923 to Poteriospumella vasocystis comb. nov. substantiated on the high sequence similarity with Poteriospumella lacustris Boenigk et Findenig and Poteriospumella maldiviensis nov. sp.
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