SKM 2023 – wissenschaftliches Programm

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CPP: Fachverband Chemische Physik und Polymerphysik

CPP 35: Poster Session II

CPP 35.34: Poster

Mittwoch, 29. März 2023, 11:00–13:00, P1

Pyrolysis of ellagic acid - a thermodynamic and kinetic study by means of quantum chemistry — •Philip Schöne, Jakob Kraus, and Jens Kortus — TU Bergakademie Freiberg (Institut für Theoretische Physik) Leipziger Str. 23, 09599 Freiberg, Deutschland

By performing ab-initio calculations, thermodynamic and kinetic data on the pyrolysis of ellagic acid were computed. The reaction path consists of two decarboxylations and two hydrolyses. The pyrolysis of ellagic acid can take place via the formation of either hexahydroxydiphenic acid or urolithin m5. Using select DFT functionals and quantum chemical methods, data for each reaction were calculated between 0 K and 1200 K. The occurring decarboxylations were found to be very similar to each other, being exothermic and exergonic reactions that become increasingly so with rising temperature. The hydrolyses show the opposite behavior, being slightly endothermic and endergonic reactions that become increasingly so with rising temperature. With the help of the climbing image nudged elastic band method, mechanisms for all reactions could be proposed and highest energy transition states could be identified. For the decarboxylations, these represent H transfers from the carboxylic group to the neighboring C atom. For the hydrolyses, the highest energy transition states correspond to H transfers from water to the nascent carboxylic group. Moreover, the rate-determining steps in the pyrolysis of ellagic acid were determined, which are the hydrolyses of urolithin m5 and luteic acid.