Studies of homogeneous acid-base reactions in ionic melts

Nowadays, the following aspects of oxoacidity investigations in ionic melts are being developed [59]  

1 FEATURES OF HIGH-TEMPERATURE IONIC SOLVENTS AS MEDIA FOR LUX ACID-BASE INTERACTIONS 

Pure oxygen-less melts contain no oxide ions in any form, and, therefore, such pure melts cannot serve as donors of O2-. The melts, which are solvents of the second kind, can affect acid-base interaction on their background in two manners by fixation of oxide ions entering in the melt and by solvation of the conjugate acid or base. However, the ionic solvents of the second kind, used in practice for different measurements and applied purposes, contain admixtures of oxide-ion donors, which are formed in the melt from initial admixtures of oxo-anions such as SO4-, COf- or OH-. The second way of appearance of oxide ion admixtures in molten media is characteristic of the melts based on alkali metal halides the process of high-temperature hydrolysis of the said halide melts results in the formation of hydroxide ions and, after their dissociation, of oxide ions  

The presence of the oxide-containing admixtures in oxygen-less melts inevitably leads to their dissociation with the formation of oxide ions. For the admixtures mentioned, these processes are described in ionic form by the following equations  

Since the concentrations of all these admixtures depend on the purity of the salts used for preparation of the melts, they are not constant. This means that at each specific melt-solvent pO, the values of the initial solvent fluctuate about a certain magnitude. For example, pure Csl and KCl-NaCl melts are characterized by pO 4, whereas for Nal and KC1-LiCl melts these values are lower and vary between 3 and 3.5. For comparison, at 298 K pure water as a solvent is characterized by the pH value equal to 7, and this value remains constant after achieving a certain degree of purity of H20. 

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Part 2. Studies of Homogeneous Acid-Base Reactions in Ionic Melts... 

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