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Research project (§ 26 & § 27)
Duration : 2021-11-01 - 2024-10-31

In this research project materials for the separation and analysis of chiral compounds based on high-performance liquid chromatography (HPLC) will be developed and evaluated. The research work is thematically located at the interface between organic and analytical chemistry, the chemistry of renewable raw materials (cellulose and other polysaccharides), and in the field of pharmaceutical analysis. The separation of chiral compounds into the respective enantiomers is an omnipresent analytical and preparative challenge in medical, pharmaceutical, and chemical disciplines. This applies to, for example, the production and purity determination of chiral drugs (e.g. ibuprofen), the pharmacokinetic profiling of optically active pharmaceuticals in both human and veterinary medicine, as well as the investigation of food contaminants (e.g. mycotoxins) and environmental pollutants (e.g. chiral fungicides and pesticides). The most common method here is direct chiral HPLC. A large number of HPLC column materials based on a wide variety of chiral selectors is already commercially available, with polysaccharide-based silica gel hybrid phases having emerged as the most powerful ones. However, these are only available in neutral form. Chiral compounds also contain acidic and basic molecular structural motifs and are therefore often present in their respective ionized form as organic salts. The aim of the project is thus to develop novel chiral ion-exchangers based on polysaccharide derivatives, which can be used in the above-mentioned disciplines for the separation of chiral organic acids and bases that were previously difficult to separate. The underlying molecular recognition mechanisms will also be investigated for a better understanding of the separation parameters.
Research project (§ 26 & § 27)
Duration : 2020-11-01 - 2023-10-31

Lignin is the most common renewable aromatic biopolymer. The molecule is still undergoing significant changes through various industrial conversion processes of wood or annual plants in the pulp and paper industry. As a result, lignin is obtained in large quantities and chemically modified form as "technical lignin". At present, an annual production of approx. 70 million tons worldwide is assumed. Despite large-scale availability, over 95% of the lignin obtained is used for energy production. As a result of the energy obtained and returned from this process, processes in the pulp and paper industry are considered to be largely energy self-sufficient. The discrepancy between availability and the very limited real use of lignin has posed a major challenge for academic and industrial research for decades - with varying degrees of intensity and success. Due to a worldwide rethinking, caused by the climate crisis and increasing carbon dioxide emissions, a clear trend towards a sustainable use of raw materials and a bio-economic overall design of various processes is becoming apparent. As a result, lignin has gained new momentum as a source of raw materials and is considered a "key player" in the substitution of petroleum-based raw materials and materials by renewable raw materials. This can be seen from the increase in research intensity and the resulting exponential growth of lignin patents in recent years. However, the implementation of existing, undoubtedly practicable ideas and their large-scale applications is progressing much more slowly. Therefore the question arises whether and why we are not yet able to fully understand and use technical lignins analogous to cellulose or petroleum? While we have had process chains for cellulose and its products for more than a hundred years to produce cellulose-based products such as paper, fibers or other derivatives, lignin is merely a waste product. Its high energetic value has been used thanks to the positive energy balance of the processes, but has otherwise only found a real material application as a niche product (lignosulfonate). Through processes such as Lignoboost (Thomani, 2009), which are already available and in use on a large scale, the isolation of technical lignins from the waste liquors of the kraft pulp process has become possible and makes technical lignin available for further processing practically worldwide.
Research project (§ 26 & § 27)
Duration : 2020-07-01 - 2022-06-30

Oxidative modification of cellulose The aim of the planned work is to achieve Lean and cost-efficient and green chemical routes to improve the properties of kraft pulp for thermoplastic materials. The cellulose chain is intrinsically rigid, which is one of the causes of its high Tg and Tm. The offered research targets to increase the mobility of the cellulose chain through oxidation chain cleavage methods, that decrease H-bonds in which the anhydroglucose units are involved and induce a major release of molecular motions within and between the chains.

Supervised Theses and Dissertations