Properties and applications of deep eutectic solvents and low-melting mixtures

Veronika Fischer
This thesis focuses on the properties, development and applications of deep eutectic solvents (DESs) and low-melting mixtures (LMMs). In the first part, novel binary and ternary DESs and LMMs are introduced. Mainly carnitine and betaine compounds were used amongst others. These ammonium compounds serve as alternative to choline, which is mostly used in DESs. Furthermore, sugar-based LMMs comprising choline chloride, urea as well as glucose and sorbitol, respectively, with varying molar ratios
more » ... e presented. An important advantage of sugar-based LMMs is their biodegradability and non-toxicity. For that reason, eco-friendly chemistry can be carried out. In the second part, different DESs were calculated with the conductor-like screening model for realistic solvation (COSMO-RS). Thereby, the influence of the hydrogen bond acceptor was studied. Phase diagrams of the melting temperature as a function of molar ratio were calculated for the choline halide-urea mixtures. The calculations were performed with the solid-liquid equilibrium (SLE) option. It computes a range of mixtures between the components and searches for possible concentrations of solidification. To corroborate the calculated results, differential scanning calorimetry was performed. In the third part of this work, a DESs comprising caffeic acid and choline chloride is used for the synthesis of caffeic acid phenethyl ester (CAPE). This DESs fulfils the requirements for an environmental friendly reaction medium. Moreover, caffeic acid acts as a part of the DESs as well as reactant. The reaction conditions were optimised and a molar conversion rate of 76.3% was achieved. In the last part, waterless and surfactantless microemulsions containing DESs were investigated. To formulate and characterise surfactantless and waterless microemulsions, two different DESs, namely choline chloride- ethylene glycol and choline chloride-urea were used as polar phase, tetrahydorfurfuryl alcohol as cosurfactant and diethyl adipate as non-polar phase. Ternary phase diagrams wer [...]
doi:10.5283/epub.31832 fatcat:thob5au75bc3dflv2kpcswgbi4