Study of lithium solvation environments in water-saturated nitrobenzene

The field of study on processes occurring at the liquid-liquid interface is discussed in chapter 1. A general introduction to the importance of study and the previous experimental methods is covered along with an introduction on how molecular spectroscopy can be used to study the kinetics and mechanism of transfer for species at the liquid-liquid interface. Chapter 2 describes the use of 7Li NMR for study of 'solvatomers' of Lithium in water-saturated nitrobenzene. The study of lithium salts of varying hydrophobicity has revealed the presence of multiple metastable solvation states of lithium in a mixed water/nitrobenzene system. The kinetics of exchange between these solvation states has also been studied and is reported in this chapter.; In chapter 3, the use of 7Li NMR for solvation studies is supplemented with 2H NMR. The use of deuterium NMR allows the consideration of solvation states from the point of view of the aqueous phase rather than the solvated species, lithium. The occurrence of the metastable solvation states can also be seen by 2H NMR but more interestingly, the high concentration of water in the samples compared to lithium allows diffusion-ordered spectroscopy study of the system. This leads to calculation of the diffusion coefficient of these solvation states. It is reported that addition of lithium salts, while clearly affecting the nature of hydrogen bonding, does not significantly influence the size of hydrated species. In chapter 4, the mixed water/nitrobenzene system is studied by FTIR. The OH stretch of water is affected greatly by the degree of hydrogen bonding. This allows study of the affect of lithium salts on the degree of hydrogen bonding in water-saturated nitrobenzene. The downside of the FTIR study is that only OH stretches resulting from 'free OH' are visible. This is because the IR stretch of the majority solvent, nitrobenzene, obscures stretches resulting from hydrogen-bonded water. This can be overcome by conducting inelastic neutron scattering studies on the system, as discussed in chapter 5. The difference in inelastic neutron scattering coefficient between hydrogen and dueterium allows subtraction of the scattering pattern for nitrobenzene. The hydrogen-bonding character of water can therefore be elucidated from the neutron scattering pattern of H2O in deuterated nitrobenzene. Since deuterium gives near-zero neutron scattering, the scattering pattern gives information about the state of water in nitrobenzene. Chapter 6 details the use of Laser Induced Breakdown Spectroscopy (LIBS) to asses the extent of ion incorporation in glass during the solvation study experiments. The increased activity of the lithium ion in a majority organic medium appears to drive the ion to the hydrated layer on the glass surface. The use of this technique for low energy, low-cost doping of glass is discussed. Chapter 7 is a discussion of overall conclusions and Chapter 8 is a look towards future work.