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Publikation Modeling-based approach towards quality by design for a telescoped process(Schweizerische Chemische Gesellschaft, 2024) Zahnd, This; Kandziora, Maja; Levis, Michael K.; Zogg, AndreasA telescoped, two-step synthesis was investigated by applying Quality by Design principles. A kinetic model consisting of 12 individual reactions was successfully established to describe the synthesis and side reactions. The resulting model predicts the effects of changes in process parameters on total yield and quality. Contour plots were created by varying process parameters and displaying the model predicted process response. The areas in which the process response fulfils predetermined quality requirements are called design spaces. New ranges for process parameters were explored within these design spaces. New conditions were found that increased the robustness of the process and allowed for a considerable reduction of the used amounts of a reagent. Further optimizations, based on the newly generated knowledge, are expected. Improvements can either be direct process improvements or enhancements to control strategies. The developed strategies can also be applied to other processes, enhancing upcoming and preexisting research and development efforts.01A - Beitrag in wissenschaftlicher ZeitschriftPublikation Micropollutants as internal probe compounds to assess UV fluence and hydroxyl radical exposure in UV/H2O2 treatment(Elsevier, 18.02.2021) Wünsch, Robin; Mayer, Carina; Plattner, Julia; Eugster, Fabienne; Wülser, Richard; Gebhardt, Jens; Hübner, Uwe; Canonica, Silvio; von Gunten, Urs; Wintgens, ThomasOrganic micropollutants (MPs) are increasingly detected in water resources, which can be a concern for human health and the aquatic environment. Ultraviolet (UV) radiation based advanced oxidation pro- cesses (AOP) such as low-pressure mercury vapor arc lamp UV/H2O2 can be applied to abate these MPs. During UV/H2O2 treatment, MPs are abated primarily by photolysis and reactions with hydroxyl radicals (•OH), which are produced in situ from H2O2 photolysis. Here, a model is presented that calculates the applied UV fluence (Hcalc) and the •OH exposure (CT•OH,calc) from the abatement of two selected MPs, which act as internal probe compounds. Quantification of the UV fluence and hydroxyl radical exposure was generally accurate when a UV susceptible and a UV resistant probe compound were selected, and both were abated at least by 50 %, e.g., iopamidol and 5-methyl-1H-benzotriazole. Based on these key parameters a model was developed to predict the abatement of other MPs. The prediction of abatement was verified in various waters (sand filtrates of rivers Rhine and Wiese, and a tertiary wastewater efflu- ent) and at different scales (laboratory experiments, pilot plant). The accuracy to predict the abatement of other MPs was typically within ±20 % of the respective measured abatement. The model was further as- sessed for its ability to estimate unknown rate constants for direct photolysis (kUV,MP) and reactions with •OH (k•OH,MP). In most cases, the estimated rate constants agreed well with published values, considering the uncertainty of kinetic data determined in laboratory experiments. A sensitivity analysis revealed that in typical water treatment applications, the precision of kinetic parameters (kUV,MP for UV susceptible and k•OH,MP for UV resistant probe compounds) have the strongest impact on the model’s accuracy01A - Beitrag in wissenschaftlicher Zeitschrift