Chloro anionic

Secondary amine extractants are used for the recovery of zinc from liquors obtained by the leaching of pyrite cinders at the Metalquimica del Nervion plant in Bilbao, Spain,69 and at the Quimigal plant near Lisbon, Portugal.91 Traces of other metals that also form chloro anions, such as copper, cadmium and iron(III), are also extracted, and both plants use a second extraction cycle with D2EHPA to further purify the zinc solution prior to electrowinning. 

The extraction of gold from PGM solutions by dibutyl carbitol is used by Inco,226 whereas extraction by methyl isobutyl ketone is used by Matthey Rustenburg Refiners.224 In both instances, the extraction of the gold immediately precedes the respective extraction steps for palladium described previously. Base-metal anions, such as FeCl4 , which are extracted at high concentrations of aqueous chloride, can be removed by contacting the loaded organic phase with water or dilute hydrochloric acid. Under these conditions, the base-metal chloro anions are converted to the aquated cations, e.g. 

The sulfato-bridged complex Na2Re2(S04)4- 8H20 has been prepared by the reaction of (BuJN),-Re2Cl8 with sulfate anion and may be reconverted to the chloro anion by reaction with refluxing hydrochloric acid in the presence of (Bu4N)C1. The structure shows the presence of weakly coordinated axial water molecules (r(Re—Re) = 2.214(1) A, r(Re—0)Hl0 = 2.28 A).159... 

Robb and co-workers have studied the kinetics of the anation of [Rh(H20)Cl5]2 by a variety of monoanions (equation 286 X = Cl, Br, I, N02, N3 or NCS).1213 The rates of anation are relatively independent of the nature of the anating ligand (k 2.9 ( 1) x 10-2s-1 at 35 °C), consistent with a dissociative mechanism. The rates of equilibration of the hexachloro, pentachloro and m-tetra-chloro anions were studied as a function of chloride concentration and the data were fitted to the kinetic expression kobs = + fcanutCl ]- The effect of pressure (1-1500 bar) was also mon-... 

The addition of Cl to A12C16 gives the simplest of the chloro anions, the tetrahedral A1C14. More complex anions are formed at higher Cl concentrations, e.g., in AlCl3/NaCl molten salt media which are sometimes employed as electrolytes and highly polar high-temperature solvents. The equilibria involved at 175 to 300°C are... 

Oxidation of M(CO)6 with halogens affords M2(CO)gXj anions, but in the presence of PMe3, neutral mononuclear species MX(CO)3(PMe3)3 are formed. The former contain three bridging halide atoms, which can be substituted by MeO or CH3C02 by reaction with methanol or acetic acid. The metal-metal distance of over 3.5 A precludes direct interaction. The dinuclear chloro anions are converted to CpM(CO)4 by reaction with LiCp and to (i76-arene)M(CO)4+ in the presence of arene and AlBr3. 

Chlorine (Cl, at. mass 35.45) exists at room temperature as a gas (CI2) which has oxidizing properties. Chlorine occurs in several oxidation states chloride -I, hypochlorite I, chlorite in, chlorate V and perchlorate VII. Chloride exhibits reducing properties towards powerful oxidants, such as Mn(VII) and Ce(IV). In its other oxidation states, chlorine has oxidizing properties. Hypochlorite and chlorite are rather unstable, and are subject to gradual disproportionation into chloride and chlorate. Of the chloro-anions, only chloride reveals strong complex-forming capacity. 

Ai-alkyl-iV-nitrosohydroxylaminato, 623 amido, 608 structure, 608 synthesis, 608 amidooxo, 634 amidopentahalo, 595 arsenato, 638 axametallacycles, 611 azido, 619 bromo anionic, 593 bromooxo, 625 carboxylatohalo, 606 carboxylatooxo, 633 chloro anionic, 593 chlorooxo, 625 chloroperoxo, 636 cyano, 623... 

The aminohalogenation of electron-deficient olefins with NCS can be promoted by hypervalent iodine reagents. First, the NXS may react with TSNH2 to generate TsNHCl, which can be oxidized by PhI(OAc)2 to form I-N bond. The chloro anion can dissociate and the generated nitrenium intermediate can immediately react with the double bond of olefins to form an aziridinium ion. A series of substrates are tolerable under the reaction conditions and are aminochlorinated or brominated in good yields with high diastereoselectivities (eq 42). ... 

The explanations tentatively proposed in the literature [20, 25, 41, 61] for the variations of gold uptake with pH as shown in Figure 17.1, depend on the gold speciation that is considered. Some groups consider the presence of hydroxo-chloro anions as identified by Raman and XAFS [27-29], while others take into account the speciation deduced from thermodynamic data, that is the presence of neutral complexes, such as AuCfi at pH 2-5 [35] (see Section 17.1). 

An electrolyte containing around 10 mM of a strong add has several advantages over more conventional capillary electrolytes (i) Silica sUanol groups are not ionized at the acidic pH used and EOF is therefore very low. (ii) No additional buffer is required because HCl or HCIO4 acts as a kind of concentration buffer and resists pH changes, (iii) Metal cations resist hydrolysis in addic solution, and metal chloro anions are stabilized by an HCl electrolyte. 

As has been seen, refluxing thionyl chloride reacts with water and may be used to prepare anhydrous metal chlorides from the hydrates. Additionally, it is a suitable solvent for the preparation of the chloro anions of metals ... 

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