Anions anomalous water

Electrolytes are used to promote the exhaustion of direct or reactive dyes on cellulosic fibres they may also be similarly used with vat or sulphur dyes in their leuco forms. In the case of anionic dyes on wool or nylon, however, their role is different as they are used to facilitate levelling rather than exhaustion. In these cases, addition of electrolyte decreases dye uptake due to the competitive absorption of inorganic anions by the fibre and a decrease in ionic attraction between dye and fibre. In most discussions of the effect of electrolyte on dye sorption, attention is given only to the ionic aspects of interaction. In most cases, this does not create a problem and so most adsorption isotherms of water-soluble dyes are interpreted on the basis of Langmuir or Donnan ionic interactions only. There are, however, some observed cases of apparently anomalous behaviour of dyes with respect to electrolytes that cannot be explained by ionic interactions alone. 

The anomalous features are observed on well-ordered (111) surfaces in a variety of electrolytes over a wide range of pH (0-11), but the potentials at which the features appear and the detailed shapes of the I-V curves vary considerably. Specifically, the potential region (versus RHE) in which the features appear changes with anion concentration in sulphate and chloride electrolytes, but not in fluoride, perchlorate, bicarbonate or hydroxide electrolyte. In sulfate electrolyte, at constant anion concentration the region shifts (versus RHE) with varying pH, while in fluoride, perchlorate, bicarbonate and hydroxide electrolyte it does not. The use of UHV surface analytical techniques has established to a reasonable (but not definitive) extent that adventitious impurities are not involved in the anomalous process, i.e., the only species participating in the chemistry are protons/hydroxyIs, water and the anions of the solute. On the basis of the pH and anion concentration dependencies, I agree with the... 

The hydration of the complexed polyether under two-phase conditions includes the specific hydration of anions, similar to that found with onium salts, and two molecules of water associated with the uncomplexed ligand. Removal of the hydration sphere of the anions in going from two phase to anhydrous conditions is balanced by a larger cation-anion interaction. This behavior causes very little variation in anionic reactivity in contrast with that observed with onium salts [40]. The hydration sphere determines in both cases the anomalous nucleophilicity scale found under PTC conditions with respect to dipolar aprotic solvents. 

The role of the solvent should become clearer when we know more about its effects on the transition state and the reactants separately so far there have been few studies of the thermodynamics of transfer of ligands and metal ions from one solvent to another, which would permit the kind of dissection of the rate parameters that has been very useful in other fields, such as (for example) the kinetics of reactions involving anions (35) At all events it is clear that water is not here a typical solvent, but an anomalous one, as in other kinetic and thermodynamic contexts, and that the role of the solvent is more complex and subtle than the results in water and would suggest. 

Ji et al. (2010,2012) discuss a number of types of reactions of organic substances in liquid ammonia, and provide many references to recent and earlier work. They compare the equilibrium constants of phenols and carbonyl-activated carbon adds in ammonia and water, and describe work that is part of an ongoing study of the kinetics of a variety of reactions, including aromatic substitutions and solvolyses in ammonia. They point out that owing to its weakness as an add and as a hydrogen-bond donor, in many respects ammonia behaves as a dipolar aprotic solvent. It solvates cations strongly, but anions hardly at all (Marcus, 1983,1985). The low value of the autoprotolysis constant ( 10 at -33°C) is chiefly due to the weakness of ammonia as an acid. The mobility of the NH ion in liquid ammonia is not anomalous (Lagowski,... 

Recently Khaled et al. [53] found that electrochemical generation of Ceo anions in toluene/acetonitrile mixtures is not 100% quantitative. Some irreversible changes could be seen in the spectra of the electrolyzed solution even when was generated. The irreversible changes occurring in the solution can be responsible for anomalous and/or inconsistent behavior observed in the ESR spectra of fullerene anions [53,100-103]. The possible role of water and OH was, however, excluded [94]. 

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