Nine structurally-related fatty acid ionic liquids have been prepared and their thermal behavior as well as their ability to self-assemble in water has been investigated. The thermal properties were studied by thermal gravimetric analysis (TGA) and differential scanning calorimetry (DSC), while the aggregation behavior was analyzed by tensiometry, isothermal titration calorimetry (ITC), conductometry, dynamic light scattering (DLS), and electrophoretic light scattering (ELS).Structural variations concerned both the imidazolium cation (presence or not of hydroxyl groups) and the anion (length of the fatty acid), and affected in different ways the ILs' properties.With regards to the thermal stability, the presence of the hydroxyl group on the cation had a beneficial effect on stability regardless of the anion's length. This latter played instead a major role in allowing the solubility of the ILs in water (C18-stearate ILs were not soluble in water) and in determining the critical micelle concentration (CMC) values, as the reduction of the anion length in moving from C16-palmitate to C14-myristate anions disfavors aggregates formation.Several other parameters characterizing the adsorption of fatty acid ILs at the air/water interface, some thermodynamic parameters of the aggregation process as well as size distribution and stability of the aggregates were also determined.
Lubricants that are based on renewable raw materials have drawn increased attention in various applications, especially those related to the food industry. Due to the high requirements of environmental protection, there is a need to develop biodegradable base oils that are environmentally friendly and do not contain harmful components. The objective of the research was to obtain a base oil with a certain viscosity and certain desired lubricating properties. Base oils were obtained from Crambe abyssinica oil by means of blending with synthetic oil and oxidation. The oxidation processes were carried out in the presence of N-hydroxyphthalimide with or without CO2 as a solvent. As a final result of this study, oil bases meeting the viscosity requirements and showing suitable lubricating properties were obtained. The Raman spectra of the obtained oils were evaluated.
Raw vegetable oil from Crambe abyssinica was subjected to oxidative treatment to enhance its viscosity. The oxidation processes were carried out in the presence of N-hydroxyphthalimide with or without supercritical CO2 as a solvent. Four spectroscopic techniques (Raman, UV-VIS, FT-IR, NMR) were applied to assess the chemical changes taking place during the oxidation. Raman and NMR spectroscopy proved best in the assessment of the chemical transformations leading to increased viscosity of the modified vegetable oil.
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