Solid metal chlorides

Stumpp, E. Gas chromatography of solid metal chlorides. Z. Anal. Chem. 242, 225 (1968). 

Ellis, C. P. A method for the introduction of unstable solid metallic chlorides onto gas chromatography columns. Anal. Chem. 35, 1327 (1963). 

The prime electrochemical difference between the two sodium-beta technologies is the sodium/metal-chloride positive electrode. This component contains a molten secondary electrolyte (NaAlClJ and an insoluble and electrochemically active metal-chloride phase (Fig. 40.1b). The secondary electrolyte is needed to conduct sodium ions from the primary /3"-AI2O3 electrolyte to the solid metal-chloride electrode. Cells using positive electrodes with two transition metal-chlorides, nickel and iron, have been developed. These specific metals were selected based on their insolubility in the molten NaAlCl4 secondary electrolyte. - During discharge, the solid metal-chloride is converted to the parent metal and sodium chloride crystals. The overall cell reactions for these two chemistries are as follows ... 

Notice that the reaction (6.7) involves the pure solid metal chlorides and pure elements in their standard states so that the free energies evaluated above are standard free energies regardless of the concentration of HCl in the cell— the latter does not enter the net formal cell reaction, or influence the cell EMF. It does however play the vital role of establishing the potentials on the two electrodes through the potential determining equilibria given above. 

Thermodynamic data show that the stabilities of the caesium chloride-metal chloride complexes are greater than the conesponding sodium and potassium compounds, and tire fluorides form complexes more readily tlrair the chlorides, in the solid state. It would seem that tire stabilities of these compounds would transfer into tire liquid state. In fact, it has been possible to account for the heats of formation of molten salt mixtures by the assumption that molten complex salts contain complex as well as simple anions, so tlrat tire heat of formation of the liquid mixtures is tire mole fraction weighted product of the pure components and the complex. For example, in the CsCl-ZrCU system the heat of formation is given on each side of tire complex compound composition, the mole fraction of the compound... 

Reactions of solid metals with liquid metals (e.g. dissolution of aluminium in mercury) Dissolution of metal in their fused halides (e.g. lead in lead chloride). 

The two principal forms of stress-corrosion failure are (a) hot salt cracking and (Z)) room-temperature cracking, the latter occurring in both aqueous and methanolic chloride environments, and in N2O4. In addition, environmental failures can occur in alloys in direct contact with some liquid and solid metals, and certain gases. 

When we study a solid that does not have the characteristic lustrous appearance of a metal, we find that the conductivity is extremely low. This includes the solids we have called ionic solids sodium chloride, sodium nitrate, silver nitrate, and silver chloride. It includes, as well, the molecular crystals, such as ice. This solid, shown in Figure 5-3, is made up of molecules (such as exist in the gas phase) regularly packed in an orderly array. These poor conductors differ widely from the metals in almost every property. Thus electrical conductivity furnishes the key to one of the most fundamental classification schemes for substances. 

Dirubidium phthalocyanine (PcRb2) and dicesium phthalocyanine (PcCs2) can be prepared by chemical-vapor deposition of benzene-1,2,4,5-tctracarbonitrile and the metal chloride.135 In the solid phase, additional rubidium atoms are complexed between peripheral cyano groups. 

A series of solid transition-metal chlorides can be used as positive electrodes in cells with sodium as the negative electrode. The various metal chlorides form electrochemical pairs with sodium showing different emf values (Table 1 ). 

In a reactor at low pressure (0.2-0.3 MPa) and moderate temperature (375 °C) the PVC is chemically and thermally degraded. A particular feature of the process is that the chlorine in the PVC reacts in part with the fillers in PVC and is neutralised with the formation of CaCl2. In similar vein, metal stabilisers in PVC are converted into the respective metal chlorides (lead, cadmium, zinc and/or barium). At current PVC waste compositions these chlorides consist of 60% lead which can be purified and re-used. The reaction in the end results in the following solid, liquid and gaseous products. 

The reaction of sodium metal with molecular chlorine gas to produce solid sodium chloride can be analyzed by breaking the overall process into a series of steps involving ions in the gas phase. 

The reader is referred the recent book by Bell and Pines [2] for a more complete overview of the various methods and objectives in NMR studies of solid acids and other heterogeneous catalysis. In the present contribution we illustrate the application of H, and MAS NMR to two archetypal solid acids, Brpnsted sites in zeolites and solid metal halides such as aluminum chloride and bromide powders which exhibit "Lewis superacidity". An important characteristic of the more recent work is the integration of quantum chemical calculations into the design and interpretation of the NMR experiments. 

Oxysalt bonded cements are formed by acid-base reactions between a metal oxide in powdered solid form and aqueous solutions of metal chloride or sulphate. These reactions typically give rise to non-homo-geneous materials containing a number of phases, some of which are crystalline and have been well-characterized by the technique of X-ray diffraction. The structures of the components of these cements and the phase relationships which exist between them are complex. However, as will be described in the succeeding parts of this chapter, in many cases there is enough knowledge about these cements to enable their properties and limitations to be generally understood. 

Over An deposited on 3-D mesoporous Ti-Si02 with pore diameter of 9nm, one of the best results was obtained. At an SV of 4000 h/mL/g-cat., propylene conversion above 8%, PO selectivity of 91% giving a steady STY of 80 g PO/h/kg-cat. [84]. The surfaces of 3-D mesoporous Ti-Si02 were trimethylsilylated for rendering hydro-phobicity, which enables higher temperature operation of reaction [86]. As a solid phase promoter, alkaline or alkaline earth metal chlorides are efficient, however, chloride anions markedly enhance the coagulation of An particles in a short period [87]. Finally, Ba(N03)2 was selected as the best promoter which might kill the steady acid sites as BaO (after calcination) on the catalyst surfaces [84,88]. 

In liquid-solid processes reaction takes place between a liquid reactant and an insoluble or sparingly soluble solid which must be finely divided to speed up the process. Another measure to accelerate the process is to use an aqueous solution of a phase-transfer agent (typically a quaternary ammonium salt). The solid can also be a catalyst for reactions between liquid components, e.g. in acylations, carried out both conventionally in the presence of metal chlorides (mostly AICI3) or catalysed by zeolites and Grignard reactions. 

Equation (3.1.50) can be developed further. Consider once again cell (3.1.40), together with Eq. (3.1.49). We shall assume that hydrogen gas is under standard pressure in addition, metallic silver, solid silver chloride and gaseous hydrogen at standard pressure are selected as standards, that is... 

When dehydrating a compound such as a metal chloride, the gaseous products of the reaction make it easy to separate the anhydrous solid compound. 

Metals which form sparingly soluble salts will also respond to changes in the activity of the relevant anion provided the solution is saturated with the salt, e.g. for silver in contact with a saturated solution of silver chloride and containing solid silver chloride the electrode reaction is AgCl + e = Ag + Cl, and the electrode potential is given by ... 

Knochel et al. (1977a) have studied the effect of the structure of the ligand on its ability to catalyse the reaction between solid metal acetates and benzyl chloride dissolved in acetonitrile. Approximate half-lives for the reactions are given in Table 29. For crown ethers, the reactivity sequence decreases in the... 

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