First the ionic liquids based on imidazolium cation will be kept and its structure with the formate and the octanoate anions will be investigated and compared together to draw conclusion about the effect of the anionic alkyl chain length on the cation/anion structures and their interactions. The second part of this project aims to examine the interactions of the formate based protic ionic liquid with water. The water will be used as a probe to quantify and to compare the interactions changes in solutions by comparing solutions structures with those obtained for pure alkanoate ionic liquids. It will be possible to analyse the balance between hydrogen bonding vs. van der Waals forces in solutions to understand the interaction between the ILs/water structures. These interactions with water have not been significantly studied. The improved knowledge of the proton transfer and the donor/acceptor competitions might underpin the mechanisms of the proton transport in the protic ILs. We believe then that there is a link between the cation/anion structure as a function of the alkyl chain length on the anion, IL/water structure, and the structure of the apolar domains where water are located.