Chloride System Research Articles

Synthesis of ethyl 2-methyl-4-(diethoxyphosphoryl)4,7-dihydro-5<i>H</i>-thiopyrano[3,4-<i>b</i>]furan-5-carboxylate and its functionalization at the position 3

Ethyl 2-methyl-4-(diethoxyphosphoryl)-4,7-dihydro-5 Н -thiopyrano[3,4- b ]furan-5-carboxylate was synthesized. It was shown that at elevated temperatures it is acetylated in presence of tin tetrachloride and chloromethylated with paraformaldehyde-hydrogen chloride system in the presence of zinc dichloride at the positon 3 of heterocyclic system. Reaction of chloromethyl derivative with N -, S - and О -nucleophiles were studied.

Spectroscopic and Electrochemical Investigation of Uranium and Neptunium in Chloride Room-Temperature Ionic Liquids.

To expand the breadth of knowledge of actinide chemistry in molten chloride salts, chloride room-temperature ionic liquids (RTILs) were used to probe the influence of RTIL cation on second-sphere coordination for anionic complexes of uranium and neptunium. Six chloride RTILs were studied to represent a range of cation polarizing strength, size, and charge density to correlate changes in the complex geometry and redox behaviors. Optical spectroscopy indicated that actinides were dissolved at equilibrium as octahedral AnCl62- (An = U, Np) as is observed in comparable high-temperature molten chloride salts. These anionic metal complexes were sensitive to the RTIL cation polarizing strength and hydrogen bond donating strength and displayed varying levels of fine structure and hypersensitive transition splitting depending on the degree of perturbation to the complex's coordination symmetry. Furthermore, voltammetry experiments on the redox-active complexes indicated a stabilizing effect on lower valence actinide oxidation states by more polarizing RTIL cations whereby the measured E1/2 potentials for both U(IV/III) and Np(IV/III) couples shifted positively by about 600 mV across the different systems. These results indicate that more polarizing RTIL cations inductively remove electron density from the actinide metal center over An-Cl-Cation bond networks to stabilize electron-deficient oxidation states. Electron-transfer kinetics were generally much slower than in molten chloride systems, partially due to lower temperatures and higher viscosities in the working systems and showed diffusion coefficients of 1.8 × 10-8 to 6.4 × 10-8 cm2 s-1 for UIV and 4.4 × 10-8 to 8.3 × 10-8 cm2 s-1 for NpIV. We also detect a one-electron oxidation of NpIV that we have attributed to the formation of NpV as NpCl6-. Overall, we observe a coordination environment for the anionic actinide complexes that is susceptible to even small changes in RTIL cation properties.

Occurrence Behaviors of As/Sb/Bi in Copper Anode Slime and Their Separation by Compound Leaching Followed by Stepwise Precipitation.

Copper anode slime is the main raw material for the extraction of rare and precious metals. However, the recovery of rare and precious metals still faces great challenges due to the variety of impurities and the complex occurrence phase. In view of this, this research focuses on the occurrence mineral phases of arsenic, antimony, and bismuth in copper anode slime, and the process consisting of chloride leaching and selective precipitation of arsenic and bismuth is proposed. The results show that in copper anode slime, As mainly exists in the form of arsenate, while Sb and Bi exist in the form of oxides. The arsenate and oxides of Sb and Bi can be effectively leached by using the compound leaching process in the chloride system. The leaching efficiencies of As, Sb, Bi, and Cu can reach 92.72, 99.98, 89.13, and 90.31%, respectively, using a H2SO4 concentration of 4 mol/L and a NaCl concentration of 120 g/L with a liquid-solid ratio of 10:1 at 70 °C for 2 h. After compound leaching, more than 98% of Sb and Bi can be separated by stepwise selective precipitation in the form of Sb4O5Cl2 and BiOCl by controlling the H+ concentration at 0.8 g/L and 0.2 g/L, respectively. After separation of Sb and Bi, the As-containing solution can be further treated by mature arsenic solidification technology. The copper-containing solution for removing arsenic, antimony, and bismuth can be returned to the electrolysis process for copper recovery. The proposed process realizes the effectively and environmentally friendly separation of As, Sb, Bi, and Cu from copper anode slime.

Dispersive adsorption and anticorrosion properties of natural capsaicin on Q235 steel in mixed H2SO4 and NaCl environment: Characterization, experimental and theoretical studies

Although traditional corrosion inhibitors have demonstrated immense relevance in metal protection for many years now, issues relating to their moderate to high toxicities, non-biodegradability, and cost-effectiveness have persisted. For these reasons, bio-based corrosion inhibitors are gathering significant research attention and have shown great potentials in the corrosion suppression of metals while being relatively cheap and eco-friendly. This study focuses on the anticorrosion and adsorption properties of natural capsaicin isolated from Capsicum annuum L. as a bio-based corrosion inhibitor for Q235 steel in a mixed acid and chloride system (0.25 M H2SO4 + 0.5 M NaCl). FTIR and NMR techniques afforded the characterization and identification of the phytocompound. Electrochemical and gravimetric measurements were employed for anticorrosion evaluations. 3D surface profilometer, SEM, and water contact angle examinations provided adsorption proof for capsaicin on steel surface. XPS provided insights into the corrosion suppression mechanism of capsaicin. Computational techniques allowed the description of the adsorption characteristics, molecular interactions, molecular orientations and binding energies of capsaicin on steel substrate. Having a maximum inhibition performance of 94.8% at 298 K, capsaicin was classified as a functional mixed-type corrosion inhibitor that is reliant on concentration and surrounding temperature for its effectiveness. While also validating the results from water contact angle measurements, 3D profiling, and SEM, XPS results disclosed that the interactions of capsaicin with steel surface leading to its adsorption and anticorrosion effect involved both physisorption and chemisorption processes, and this was in perfect correlation with the Langmuir monolayer adsorption model.

Corrosion of Titanium Alloys Anodized Using Electrochemical Techniques

The anodization of titanium has been an excellent option for protecting titanium and its alloys from corrosive environments such as acids and chloride systems, by generating a homogenous oxide layer. The objective of the current investigation was to evaluate the electrochemical corrosion behavior of alloys Ti-6Al-2Sn-4Zr-2Mo and Ti-6Al-4V anodized in 1M H2SO4 and H3PO4 solutions at a current density of 2.5 × 10–3 A/cm2. The anodization’s electrochemical characterization was achieved in NaCl and H2SO4 at 3.5% wt. electrolytes. Scanning electron microscopy (SEM) was employed to determine the anodized thickness and morphology. Cyclic potentiodynamic polarization (CPP) and electrochemical impedance spectroscopy (EIS), based on ASTM G61-86 and G106-15 Standards, were the electrochemical techniques mainly employed. The anodized samples presented a change in Ecorr values and a higher passivation zone. The EIS plot showed a higher resistance for samples anodized in H3PO4 and Ti-6Al-2Sn-4Zr-2Mo.

High-Performance Polyamide Reverse Osmosis Membrane Containing Flexible Aliphatic Ring for Water Purification

A reverse osmosis (RO) membrane with a high water permeance and salt rejection is needed to reduce the energy requirement for desalination and water treatment. However, improving water permeance while maintaining a high rejection of the polyamide RO membrane remains a great challenge. Herein, we report a rigid-flexible coupling strategy to prepare a high-performance RO membrane through introducing monoamine with a flexible aliphatic ring (i.e., piperidine (PPR)) into the interfacial polymerization (IP) system of trimesoyl chloride (TMC) and m-phenylenediamine (MPD). The resulted polyamide film consists of a robust aromatic skeleton and soft aliphatic-ring side chain, where the aliphatic ring optimizes the microstructure of polyamide network at a molecular level. The obtained membranes thereby showed an enhanced water permeance of up to 2.96 L·m-2 h-1 bar-1, nearly a 3-fold enhancement compared to the control group, meanwhile exhibiting an ultrahigh rejection toward NaCl (99.4%), thus successfully overcoming the permeability-selectivity trade-off limit. Furthermore, the mechanism of the enhanced performance was investigated by molecular simulation. Our work provides a simple way to fabricate advanced RO membranes with outstanding performance.

Nanofoaming by surfactant tunes morphology and performance of polyamide nanofiltration membrane

Fabricating nanofiltration (NF) membrane with a crumpled structure is promising for improving water permeance without compromising selectivity. Nanobubbles, which are in-situ produced during the interfacial polymerization (IP) of m-phenylenediamine (MPD)/trimesoyl chloride (TMC) system, enabled templating the “ridge-and-valley” structure of thin-film composite (TFC) reverse osmosis (RO) polyamide (PA) membranes. However, the templating effect of nanobubbles in NF PA membrane fabrication is rarely aware in the literature. Herein, we used a surfactant [sodium dodecylbenzene sulfonate (SDBS)] for reducing the interfacial tension and foaming, which enabled introducing additional nanobubbles into the piperazine (PIP)/TMC system. This would ensure that there are adequate amounts of nanobubbles to shape the PA structure, facilitating the encapsulation of nanobubbles between the PA layer and the substrate to form a bubble-like crumpled structure. The bubble-like crumpled structure increased the specific surface area and nanovoids of PA layer, beneficial for the improvement of membrane water permeance. In the presence of SDBS, the elimination of nanobubbles could change the crumpled structure to a smooth surface, while the enhancement of nanobubbles enabled more intensified crumpled structures. Our study provided a new dimension to manipulate the nanoscale structure of the PA layer of TFC NF membranes.

High-yield synthesis of HMF from glucose and fructose by selective catalysis with water-tolerant rare earth metal triflates assisted by choline chloride

Hydroxymethylfurfural (HMF) derived from sugars through an environmentally friendly process catalysed by metal triflate/choline chloride system is presented in this study.

Facile sulfation of cellulose via recyclable ternary deep eutectic solvents for low-cost cellulose nanofibril preparation.

Here we present a new method to treat cellulose with a sulfamic acid-urea-choline chloride (ternary deep eutectic solvent) system, which can realize both swelling and sulfation of cellulose. This can greatly reduce the energy consumption in the process of cellulose nanoization, and use it to successfully prepare food packaging films for eliminating odors. We hope that due its simplicity and resource-efficiency, this method will have a widespread influence on currently used (nano) cellulose modification protocols.

Rapid Fabrication of Pineapple Leaf Fibers from Discarded Leaves by Using Electrolysis of Brine

Instead of contributing to global warming by the traditional method—burning crop wastes—in this study, discarded pineapple leaves were rapidly turned into multifunctional fibers: pineapple leaf fibers (PALF). In addition, the presence of pure hydrogen during treatment can be a competitive advantage. PALF were extracted by a conventional technique, then immersed into sodium hydroxide 6% before it was treated with an electrolysis system of sodium chloride 3%. The crystallinity index increased 57.4% of treated PALF, and was collected from XRD. Meanwhile, the removal of hemicellulose and lignin in the fiber formation was presented at the absorbance peak of around 1730 cm−1 by FTIR spectrums. Simultaneously, the purity of hydrogen reached 99% and was confirmed by GC analysis. The obtained PALF and hydrogen can be used for further consideration, aiming for a circular economy.

Multi-metal electrochemical response mechanism for direct copper recovery from waste printed circuit boards via sulfate- and chloride-system electrolysis

Metal recycling from waste printed circuit boards (WPCBs) is crucial for resource sustainability. Electrolysis is promising in simplifying processes, improving recycling efficiency, and reducing consumption, while full knowledge on multi metal fate and response mechanism is indispensable for processing complex metals (Cu-Fe-Sn-Pb-Ni-Ag-Au) from WPCBs. Here, we studied multi metal responses in sulfate- and chloride-system electrolysis and realized direct copper recovery from WPCBs. Owing to ligand effects on metal redox potential, coordinates stability, and reaction kinetics, chloride system saves half energy by shifting Cu2+/Cu to Cu+/Cu, holds stable ionic lead and tin species, poses high silver loss, and produces cathode of higher surface quality. Both systems directly upgrade copper from 86% to ∼99.9% with detailed reaction pictures constructed. More environmental benefits are revealed through environmental impact comparison. The role of electrolysis for metal recycling from WPCBs were further discussed, being an important “hub” for efficient multi metal separation and extraction.

Thermodynamic measurements and assessments for LiCl-NaCl-KCl-UCl3 systems

Thermodynamic descriptions of higher-order molten salt systems are essential for the effective application of molten salt technologies. However, for pyroprocessing and molten salt reactor development, a complete description of the key Li-Na-K-U(III) chloride system has yet to be provided. To remedy this, we applied the CALculation of PHAse Diagrams (CALPHAD) approach to all available phase equilibria and related thermodynamic measurements that include new differential scanning calorimetry (DSC) observations for pseudo-binary and pseudo-ternary systems to obtain consistent and accurate sets of thermodynamic properties. An outcome of that effort was the apparent discovery of a previously unreported intermediate compound in the NaCl-UCl3 system. In this effort, we adopted a unique approach to the quantification of uncertainty in phase equilibria obtained from DSC measurements, which can provide distinct advantages in phase diagram analysis. The methodology indicates that reported values of uncertainty are often underestimated. The assessed systems of the current effort were incorporated in the publicly available Molten Salt Thermal Properties Database - Thermochemical.

A facile one-step gel process for precipitation of multifractal NaCl crystals and morphology evolution from sodium silicate gel

• Crystallization of NaCl in colloidal-salt system by a one-step gelation process. • Varying the pretreatment and gel conditions synthesizes DLA and dendrite patterns. • XRD analysis explains the dendrite pattern with distinct preferred orientation. • <110> and <111> directions determine the three- and four-fold symmetry dendrites. • Higher gelation degree contributes to precipitate regular fractal dendrite. In the colloidal-salt system of sodium silicate and sodium chloride, three-fold and four-fold symmetric dendrites and diffusion-limited aggregation (DLA) of sodium chloride crystals have been synthesized by a simple one-step gelation process without changing the solution composition. The morphology variation is realized by changing the sol pretreatment and gelation process’s heating mode. And the gelation degree of sodium silicate and the anisotropy of crystal growth is the morphology formation mechanism. Four-fold symmetric dendrites are related to preferential growth in the <110> direction, while three-fold symmetric dendrites are due to preferential orientation changes from <111> to <100> and then to <111>. EDS composition analysis showed that the high gelling degree is more accessible to precipitate regular fractal dendrites with preferred orientation.

Enhanced hydrogen generation in a combined hybrid cycle using aluminum and cooper oxide nanomaterial based on biomass and vanadium chloride cycle: Optimization based on deep learning techniques and Environmental appraisal

The usage of Nanofluid to enhance heat transfer has been investigated by many researchers in small-scale heat transfers; however, in large-scale power plants, it has not been taken care of. In this research paper, a newly proposed energy system for hydrogen generation based on renewable sources is proposed and analyzed in detail. Unlike other power input systems, the vanadium chloride system generates hydrogen because it uses waste heat. In this regard, the nanoparticles of Al2O3 and CuO are utilized in the main heat exchanger to enhance the heat transfer to the reactor of VCLC to generate more hydrogen. Also, the compound system has the gasifier-based internally fired gas turbine as the main system and can generate hydrogen in a more green way. The optimization based on deep learning methods is applied to seek the highest point of operation by the system. The results exhibit that Al2O3 causes more heat transfer and efficiency enhancement, thus in hydrogen production, causing an increase of 18.5% compared to base fluid and 8.3% compared to CuO in H2 Generation In circumstances when it is optimal, the values for exergetic efficiency and total hydrogen production are 64.5% and 4.5 kg/s respectively. In addition, using a nanofluid heat exchanger and biomass energy reduces CO2 emissions to 0.91 kg/kWh.

On the Employment of a Chloride or Fluoride Salt Fuel System in Advanced Molten Salt Reactors, Part 1: Thermophysical Properties and Core Criticality

Molten salt reactors (MSRs), as one of the six main technologies of Gen IV, can meet the broad area of sustainability, economics, safety and reliability, proliferation resistance and physical protection goals. One of the main and first challenges in designing molten salt fast reactors (MSFRs) is the selection of an appropriate molten salt fuel system based on the envisaged applications and objectives. In this study’s series, a full-scope evaluation has been conducted about employing either chloride or fluoride salt fuels as the main competitors’ candidates for fuel salt in MSFR designs. Two distinguished projects, EVOL (CNRS, Grenoble-France), based on fluoride salt, and iMAGINE (The University of Liverpool, UK), based on chloride salts, were considered in order to achieve this goal as case studies. The first part of this series (part 1—this article) deals with the investigation of the thermophysical properties of the salt fuel system, criticality search and neutron-flux energy spectrum. An identical typical design of the MSFR core has been considered for a neutronic simulation by using MCNPX V2.7 based on the chemical composition of the fuel salt mentioned in both projects. The thermophysical evaluation has been conducted through literature research and theoretical methods based on the experimental values for the salt component properties. The results of the study are presented for thermophysical properties, including the melting point, vapour pressure/boiling point, specific heat capacity, thermal conductivity and density, in addition to neutronic simulation for the core critical dimension and neutron-flux spectrum of both the chloride- and fluoride-based salt fuel systems. In the discussion of the results, it is concluded that both the chloride and fluoride salt fuel systems have benefits that are seen on different comparative parameters. The delivered data will provide future decision makers with evidence for the salt choice for balancing their design objectives with the opportunities and expectations. Thus, a final selection of the most appropriate salt fuel system to be used in MSFRs will be postponed for more investigation in the final part of this article series, combining the data with different potential user profiles.

Green hydrometallurgical extraction of metallic lead from spent lead paste in the methanesulfonic acid system

As the mainstream process for recycling waste lead-acid battery paste to produce metallic lead ingots, pyrometallurgical smelting generally suffers from disadvantages such as high energy consumption, lead vapor and sulfur dioxide emissions. Hydrometallurgical extraction has received widespread attention because of its energy-saving and environmentally-friendly features. An innovative and efficient process for the hydrometallurgical recovery of lead paste was presented in this paper. In order to significantly improve the leaching efficiency of lead, PbSO4 in the lead paste was firstly converted into acid-soluble Pb3(CO3)2(OH)2 or NaPb2(CO3)2OH in Na2CO3 solution. At the same time, the insoluble PbO2 was reduced to PbO by the addition of Na2SO3. The pretreated product was then leached in MSA solution to obtain the lead-containing leachate, which was finally electrodeposited to produce lead deposits and to regenerate MSA. Under the optimized conditions, a dense and flat lead plate (purity greater than 99.99 %) could be obtained and the total lead recovery ratio in the whole process can reach 95.28 %. The cathode current efficiency and specific energy consumption in the lead electrodeposition procedure were 99.31 % and 598.91 kWh/t Pb, respectively. The electrolyte waste could be returned to the leaching process as the leaching agent. In contrast to the traditional fluorosilicate/fluoroborate and chloride systems, the environmentally-friendly MSA system with high lead solubility and low volatility, has promising applications in the field of lead hydrometallurgy.

The viscosity of aqueous solutions as analogs to cryovolcanic liquids

Effusive cryovolcanism may have occurred now or in the past on several icy bodies of the outer solar system. Our understanding of the physical properties of potential cryolavas is hindered by the limited range over which experimental data exist at appropriate conditions. The viscosity of the purely liquid phase is poorly constrained, yet, is a required component for understanding subsurface oceans, cryomagma ascent/transport, and subsequent evolution during emplacement. However, limited data exist for the viscosity of brines extending down temperature (<0°C). We have thus measured the viscosities of a broad range of binary aqueous systems at a range of temperatures and concentrations. These include the water-rich side of the eutectic for chloride (Na, K, NH4), sulfate (Mg, K, NH4), ammonia, and methanol systems between −35 and 30 °C. For geological applications, the effect of temperature on viscosity is often a larger control than the effect of concentration. We therefore constructed a model of viscosity based on the Vogel-Fulcher-Tammann equation, commonly used for silicate melt viscosities. This semi-empirical, temperature dependent model was parameterized for a given composition to account for the concentration dependence. Our model reproduced the experimental dataset to within 10 % relative uncertainty (typically within 5 %) and reproduces exactly the curve defined for pure water. The model is capable of extrapolating down to sub-ambient temperatures relevant to cryovolcanism without any singularities. Preliminary investigation of ternary systems (H2O-NaCl-MgSO4 & H2O-NH3-CH3OH) suggests this model can be successfully extended to more complicated multi-component systems. This relatively straightforward scalability and the coupled temperature and concentration dependence are key improvements over previous, more complicated models. The viscosity data produced in this study covers a poorly investigated temperature range and can be applied to cryovolcanic processes on icy bodies.

Development of a Library of Extremely Bulky Amide Ligands, and their use for the Stabilization of Germanium(I) and Germanium(II) Compounds

AbstractEleven new extremely bulky aryl/silyl substituted secondary amines, L1–11H, have been prepared. These incorporate a combination of one of the bulky aryl groups, C6H2{C(H)Ph2}2R‐2,6,4; R=Me (Ar*), Pri (Ar†); C6H2{C(H)(C6H3But2‐3,5)2}2Me‐2,6,4) (Ar#); or C6H2{C(H)(2‐naphthyl)2}2Me‐2,6,4 (Ar¥), and one of the silyl fragments, SiMe3, SiCy3 (Cy=cyclohexyl), SiPri3, Si(p‐C6H4But)3, or Si(OBor)3 (OBor=[(1S)‐endo]‐(−)‐borneoxy). Amines including the latter silyl group represent the first enantiopure examples of this ligand class. All amines are readily deprotonated with n‐butyllithium or KH. Reactions of five alkali metal amide complexes with GeCl2⋅dioxane have given monomeric amido‐germanium(II) chloride complexes, LxGeCl (x=1–4, 7). Treatment of two of these with KOBut afforded monomeric amido‐germanium(II) tert‐butoxide species, LxGeOBut (x=1 or 3). Reductions of two amido‐germanium(II) chloride systems with a dimagnesium(I) compound afforded amido‐digermyne species, LxGeGeLx (x=3 or 4), the X‐ray crystal structures of which show them to possess very short Ge−Ge bonds, with considerable implied multiple bond character.

50 Years with Lithium Batteries

The discovery of 7 still available primary battery systems involving the lithium anode occurred some 50 years ago in the period of 1970 to 1973. The discoveries (and many others which did not survive competition) were made in a number of industrial and academic laboratories, including Union Carbide’s Parma Technical Center, where I led the lithium research group. These studies were part of a world-wide search to find satisfactory cathodes and electrolytes to take advantage of the remarkable properties of lithium as an anode. The well-known advantages of lithium give it almost ideal properties as a battery anode except that it is very difficult to handle in air due to reaction with both oxygen and nitrogen and reacts with any solvent containing dissociable protons to form hydrogen gas. The work by W.S. Harris in 19581 established that solvents such as propylene carbonate, ethylene carbonate and butyrolactone were stable in the presence of lithium metal giving impetus to the search for appropriate lithium battery cathodes.The anodes all utilized thin lithium foil (usually in the range of 100 to 200 μm) contacted by a nickel, copper or stainless steel tab, or container body, while the cathodes and electrolytes were of three types: 1.) solid cathode with liquid electrolytes, 2.) solid cathode with solid electrolyte and 3.) liquid cathode with liquid electrolyte. Two solid cathodes with liquid electrolyte were carbon monofluoride and manganese dioxide in the 3V class came from laboratories in Japan. A third solid cathode in the 1.5V class was iron disulfide (the mineral pyrites) came from our laboratory in the U.S. in this period, but was not disclosed until 1978. This cathode was first discussed in a high temperature cell with lithium alloy anodes by Argonne National Laboratory in the U.S.The lithium iodine cell with an in-situ formed LiI solid electrolyte was discovered in the laboratories of the Jet Propulsion Laboratory of NASA and developed independently by several U.S. companies, mainly Catalyst Research Corp. and Wilson Greatbatch Ltd. A key component of the cell is polyvinylpyridine which is mixed with iodine under heat to form a liquid slurry, which is poured into the cathode compartment of the cellLithium/sulfur dioxide was the first liquid cathode-liquid electrolyte cell and was patented by American Cyanimid Co.in the U.S. in 19712. An example in the patent corresponds closely to the present contents involving a lithium sheet anode with a carbon collector for the cathode and an electrolyte containing LiBr salt with sulfur dioxide and acetonitrile solvents. Work at our laboratory discovered the lithium/thionyl chloride and lithium/sulfuryl chloride systems. The patent was filed in 1971, but patent acceptance was delayed by an interference proceeding until 19833. The feature of these systems was the absence of any co-solvent such as acetonitrile which allowed higher energy density. The properties of these batteries as available will be discussed and the systems compared for advantages and disadvantages

Electrochemistry of Neodymium in an Equimolar NaCl-KCl Melt without and with Addition of Fluoride Ions

An investigation of compounds of those few elements in the oxidation state (II), by opposition to the general trivalent lanthanides is of special interest. The present work follows our previous investigations on samarium, europium ytterbium chloride systems and, in particular, the electrochemical behavior of the Sm(III)/Sm(II), Eu(III)/Eu(II) Yb(III)/Yb(II) redox couples. It deals with neodimium compounds.The electrochemical behavior of NdCl3 in molten salts was studied in few works, but only melts with a low melting point LiCl-KCl and LiCl-KCl-CsCl were investigated.The electroreduction of NdCl3 in an equimolar NaCl-KCl mixture was studied in the temperature range 973-1123 K by different electrochemical methods. It was shown that the discharge of Nd(III) to Nd(II) is complicated by the disproportionation reaction (DPP):3Nd(II) ↔ 2Nd(III) + Nd (1)Ignoring of reaction DPP can lead to incorrect determination of values diffusion coefficients and formal standard redox potentials of the Nd(III)/Nd(II) redox couple. The relatively narrow interval of polarization rate was found when the recharge process was reversible and not accompanied by the DPP reaction. At these scan rates the diffusion coefficients and formal standard redox potentials of the Nd(III)/Nd(II) redox couple were determined by cyclic voltammetry.The standard rate constants for the redox reaction Nd(III) + e- ↔ Nd(II) were calculated on the basis of cyclic voltammetry at sweep rates corresponding to the quasy-reversible process. The nature of working electrode on the rate of charge transfer for the Nd(III)/Nd(II) redox couple was studied. It was found that the values of k s determined at a molybdenum electrode were higher than those at a glassy carbon electrode.The introduction of fluorine anions into a chloride melt at a molar ratio of F-/Nd(III) = 5 leads to the disappearance of the recharge wave and only an ascending section associated with joint discharge of neodymium complexes and sodium and potassium cations was observed. Thus, the introduction of fluorine anions leads to stabilization of the highest oxidation state of neodymium in chloride-fluoride melt and neodymium in the oxidation state +2 does not exist in the melt.Introducing of fluoride ions to the melt NaCl-KCl containing Nd(II) accompanied by reaction of disproportionation:3NdCl4 2- + 12F- ↔ 2NdF6 3- + Nd + 12Cl- (2)The standard rate constants of charge transfer for the Nd(III)/Nd(II) redox couple were compared with the values obtained for other redox couples of lanthanides and these results were discussed in connection with the strength and stability of complexes.