Copper Chloro Research Articles

Speciation of copper in high chloride concentrations, in the context of corrosion of copper canisters

AbstractCanisters with a cast iron insert for mechanical strength and a 50‐mm thick copper shell as corrosion protection are planned to be used for disposal of spent nuclear fuel in Sweden and Finland. Chloride can be considered “beneficial”, as it promotes active dissolution of copper rather than passivation (which might result in pitting), but a high concentration of chloride in solution would increase the driving force for corrosion through the formation of soluble copper chloro complexes. Thermodynamic calculations are performed in this study with the PHREEQC software and three of its accompanying databases, and a comparison with experimental data is performed to select the database to be used when evaluating repository performance. The activity coefficient models are given special attention. For the assessment of chloride‐assisted corrosion of a KBS‐3 canister, chloride concentrations pessimistically up to 5 mol/kg are used (in Finland and Sweden, the groundwater and bentonite porewater chloride concentrations are not expected to exceed 1 mol/kg). The resulting copper solubilities are then considered in different mass transport cases.

Description and performance of a novel aqueous all-copper redox flow battery

In this paper we present a novel aqueous redox flow battery chemistry based on copper chloro complexes. The energy density (20 Wh L−1) achieved is comparable to traditional vanadium redox flow batteries. This is due to the high solubility of copper (3 M), which offsets the relatively low cell potential (0.6 V). The electrolyte is cheap, simple to prepare and easy to recycle since no additives or catalysts are used. The stack used is based on plain graphite electrode materials and a low-cost microporous separator. The system can be operated at 60 °C eliminating the need for a heat exchanger and delivers an energy efficiency of 93, 86 and 74% at 5, 10 and 20 mA cm−2 respectively.

Two Mechanisms of Chlorocuprate Reactions with Alkyl Radicals: Dramatic Role of Nuclearity

Interaction of copper chlorides with radicals is a key step of single electron transfer reactions and is responsible for high selectivity of copper-catalyzed radical processes. In the present article reactions of binuclear copper(II) chlorides with methyl radical were studied in the scope of density functional theory. The results of quantum-chemical calculations of potential energy surfaces allow proposing that there are at least two reasons for the lower activity of binuclear complexes Cu2Cl62– in comparison with CuCl42–. First, the radicals react with binuclear chlorocuprates via an atom transfer mechanism through an activation barrier, in contrast to the barrierless character of such reactions with partition of CuCl42–. Second, only in the systems with binuclear copper chloro complexes may an alternative path of spontaneous formation of chloroorganocuprates be realized. These intermediates may be dormant species in radical reactions.

Synthesis, Characterization and Magnetochemical Studies of Some Copper(II) Complexes Derived from Tetrakis(N-Salicylidene)ethanetetracarboxylic Acid Tetrahydrazide

Copper(II) complexes of a new salicylaldehyde tetrahydrazone, H8L derived from ethanetetracarboxylic acid tetrahydrazide, have been synthesized. Three types of copper(II) complexes Cu4(L).6H2O, Cu4(H4L)(NO3)4.7H2O and Cu4(H4L)Cl4.3H2O have been isolated and characterized by elemental analyses, infrared spectra, ultraviolet-visible spectra, as well as variable temperature magnetic susceptibility measurements. Magnetic susceptibility measurements of Cu4(L).6H2O and Cu4(H4L)(NO3)4.7H2O indicate significant antiferromagnetic coupling between copper(II) centers. The –2J values obtained from the Bleaney–Bowers equation equal 213 and 203 cm−1 suggest association of the coordinated copper(II) units Cu(ONO) via phenolic oxygen bridges. This gives rise to a polynuclear structure in which dimerization of coordinated acylhydrazone residues occurs. The chloro copper(II) complex Cu4(H4L)Cl4.3H2O also shows strong antifer-romagnetic exchange coupling (–2J = 472 cm−1), suggesting a polynuclear structure in which the copper(II) is in a distorted square-pyramidal environment, bound in the equatorial plane with a monomeric ONO tridentate acylhydrazone unit, and the bridged phenoxy oxygen and the axial site occupied by a chloride ion.

Selective oxidation of phenols using copper complexes encapsulated in zeolites

The oxidation and hydroxylation of phenols to dihydroxy aromatic compounds have been investigated using phthalocyanines and substituted (chloro- and nitro-) phthalocyanines of copper encapsulated in zeolites (X and Y). H 2O 2 has been used as oxidant. At ambient conditions, the encapsulated copper chloro- and nitro phthalocyanine complexes, unlike their unsubstituted analogs, are able to oxidise, selectively, phenol to catechol and hydroquinone. The catalytic efficiency (turnover number) of the copper atoms are higher in the encapsulated state compared to that in the “neat” complex. The solid catalysts have been characterised by IR, UV, ESR and ESCA spectroscopy. The influence of various process parameters (like temperature, reaction time, substrate/oxidant ratio, catalyst weight etc.) on the conversion and product distribution is also illustrated and discussed.

Chlorine nuclear quadrupole resonance in some chloro complexes of divalent copper

Nuclear quadrupole resonance for the 35Cl nucleus has been observed in some chloro complexes of divalent copper. Square-planar complexes each show two resonance lines, with the following frequencies (at 77�K): (CH3NH3)2CuCl4, 10.780, 12.157 MHz; (C2H5NH3)2CuCl4, 10.817, 12.074 MHz; (enH2)CuCl4, 10.271, 11.901 MHz; and (C3H7NH3)2CuCl4 at 223�K, 11.290 and 11.781 MHz. NH4CuCl3, containing dimeric Cu2Cl62- units, has resonances, at 77�K, at 11.907, 11.993, and 12.448 MHz. The trigonal pyramidal anion in Co(NH3)6CuCl5 has two resonances at 9.642 and 10.352 MHz at 77�K. ��� These results are compared with previous results for copper chloro complexes, and the implications of covalent bonding are discussed. In particular, it is suggested that the long-bond interaction between units in square-planar complexes amounts to 7-16% of the bonding interaction within the units.

Dimeric and Tetrameric Complexes of Copper(O) : a Correction

RECENTLY1 we reported that treatment of tris(triphenylphosphine)chloro copper (I) with hydrazine in alkaline alcoholic solution yielded a compound of empirical formula Cu(PPh3)2. Analytical data (Table 1) were consistent with this formulation, the standard method for the detection of chlorine having proved negative. Further study has shown that some chlorine is indeed present and furthermore, by chance, analysis for C, H and P does not distinguish this compound from the starting material [Cu(PPh3)3Cl]0.