% IMPORTANT: The following is UTF-8 encoded. This means that in the presence % of non-ASCII characters, it will not work with BibTeX 0.99 or older. % Instead, you should use an up-to-date BibTeX implementation like “bibtex8” or % “biber”. @PHDTHESIS{Wiesenthal:964181, author = {Wiesenthal, Jan}, othercontributors = {Klankermayer, Jürgen and Leitner, Walter}, title = {{S}ynthesis of cyclic acetals utilizing homogeneous and immobilized transition metal catalysts}, school = {RWTH Aachen University}, type = {Dissertation}, address = {Aachen}, publisher = {RWTH Aachen University}, reportid = {RWTH-2023-08154}, pages = {1 Online-Ressource : Illustrationen, Diagramme}, year = {2023}, note = {Veröffentlicht auf dem Publikationsserver der RWTH Aachen University; Dissertation, RWTH Aachen University, 2023}, abstract = {The transition to greenhouse gas neutrality represents a key challenge for the chemical Industry. In addition to more efficient processes and energy generation with lower CO2 emissions, the use of renewable resources is becoming increasingly important.This work used tailored catalysts to synthesize various cyclic acetals from biomass, CO2, and hydrogen. The versatile acetal products can be used as renewable monomers, solvents, intermediates, and fuels. In the first part, a homogeneous ruthenium-catalyst combined with a Lewis acid was used as the catalytic system to synthesize acetals from biogenic feedstock. The substrates were directly obtained from a fermentation process and converted to 4,5-diethyl-1,3-dioxolane and 4,5-dipropyl-1,3-dioxolane using CO2 or formic acid. After producing the acetals on a larger scale, initial combustion properties were determined to evaluate their feasibility as bio-hybrid fuels. In the next step, the 3d metal cobalt was tested as catalytic metal. Cobalt was capable of catalyzing the synthesis of cyclic acetal and promising results were obtained by tailoring the triphos ligand. In detail by substituting the phenyl moieties at the phosphorous with 3,5 dimethylphenyl an increase in activity could be observed. For future application of the catalyst system continuous processes, the immobilization of the molecular catalysts is a key factor. Three ligands, vinylSi-triphos, triethoxysilyltriphos, and, triphos-OH, were synthesized, having functional groups allowing immobilization. All ligands are capable of forming the corresponding [Ru(ligand)(tmm)] complex. Using [Ru(triethoxysilyltriphos)(tmm)] immobilized on SBA, cyclic acetals were successfully synthesized in batch and continuous settings. In the next step, a styrene moiety was added to the triphos-OH ligand and via radical copolymerization the triphos was immobilized within a polystyrene polymer. In first test reactions, this solid catalyst showed activity in the synthesis of 1,3-dioxane from 1,3-propanediol, CO2 and H2.}, cin = {154310 / 150000}, ddc = {540}, cid = {$I:(DE-82)154310_20190725$ / $I:(DE-82)150000_20140620$}, pnm = {DFG project 390919832 - EXC 2186: Das Fuel Science Center – Adaptive Umwandlungssysteme für erneuerbare Energie- und Kohlenstoffquellen (390919832) / BMBF 03SF0566P0 - Verbundvorhaben NAMOSYN (BMBF-03SF0566P0)}, pid = {G:(GEPRIS)390919832 / G:(DE-82)BMBF-03SF0566P0}, typ = {PUB:(DE-HGF)11}, doi = {10.18154/RWTH-2023-08154}, url = {https://publications.rwth-aachen.de/record/964181}, }