Widyastuti, Catur Rini (2022)
A Chemical Reaction Engineering Study on Non-Noble Metal Coordinated-Nitrogen Doped Carbon Catalysts for Liquid Phase Oxidation of Alcohols.
Technische Universität Darmstadt
doi: 10.26083/tuprints-00021869
Dissertation, Erstveröffentlichung, Verlagsversion
Kurzbeschreibung (Abstract)
Metal coordinated nitrogen doped on carbon (M-N-C) catalysts such as Fe-N-C and Co-N-C have been successfully implemented for oxygen reduction reaction (ORR) in fuel cell, to date these catalysts also demonstrated high activity for various organic transformation. The previous studies show that catalysts are active and selective in liquid phase benzyl alcohol oxidation. While selectivity was reported at full conversion, an assessment of the kinetics needing partial conversion is missing. This is important to truly compare the performance of different catalysts. In the present work, a proper protocol was developed to determine the kinetics of catalysts based on chemical reaction engineering study. The protocol was applied for evaluating the kinetics of several type of Co-N-C catalysts which were synthesized through different routes. This kinetic assessment was also used as the basis for a true stability investigation. The Co-N-C catalysts were synthesized through different impregnation procedures prior to pyrolysis at 700-800 °C under inert conditions. The catalytic activity was tested in a benchmark reaction of direct oxidative esterification of benzyl alcohol. The reaction was carried out in a semi-batch of slurry reactor and with continuously bubbling air at operating temperature of 60 °C. A smaller scale set-up of slurry reactor with gas simply pressed up was used for orientation studies but showed gas-phase mass transfer limitations. For the kinetic investigation it was ensured to operate in the kinetically controlled regime without mass transfer limitations. The result shows a simplified first order power law model with the optimum parameters were in a good agreement with the experimental data. As kinetic description, a consecutive reaction from benzyl alcohol to benzaldehyde and then methyl benzoate described with first order power law kinetics proofed to be efficient. All the investigated catalysts show high selectivity towards the ester product. The study shows that the first reaction step towards benzaldehyde is in minimum one magnitude slower compared to the consecutive reaction to methyl benzoate. Strong activity differences of nearly one order of magnitude can be observed for all the investigated catalysts, while a polyaniline derived catalyst employing an additional acid leaching, shows the highest activity. The catalyst stability was evaluated, showing strong dependency of catalytic activity on the base concentration, however, increasing in the deactivation behavior of the catalyst. Furthermore, base concentration of 5 mol% at sufficient catalyst mass loading was known to drive the reaction rate with less influence of catalyst deactivation.
Typ des Eintrags: | Dissertation | ||||
---|---|---|---|---|---|
Erschienen: | 2022 | ||||
Autor(en): | Widyastuti, Catur Rini | ||||
Art des Eintrags: | Erstveröffentlichung | ||||
Titel: | A Chemical Reaction Engineering Study on Non-Noble Metal Coordinated-Nitrogen Doped Carbon Catalysts for Liquid Phase Oxidation of Alcohols | ||||
Sprache: | Englisch | ||||
Referenten: | Etzold, Prof. Dr. Bastian J. M. ; Rose, Prof. Dr. Marcus | ||||
Publikationsjahr: | 2022 | ||||
Ort: | Darmstadt | ||||
Kollation: | XIII, 129 Seiten | ||||
Datum der mündlichen Prüfung: | 20 Juni 2022 | ||||
DOI: | 10.26083/tuprints-00021869 | ||||
URL / URN: | https://tuprints.ulb.tu-darmstadt.de/21869 | ||||
Kurzbeschreibung (Abstract): | Metal coordinated nitrogen doped on carbon (M-N-C) catalysts such as Fe-N-C and Co-N-C have been successfully implemented for oxygen reduction reaction (ORR) in fuel cell, to date these catalysts also demonstrated high activity for various organic transformation. The previous studies show that catalysts are active and selective in liquid phase benzyl alcohol oxidation. While selectivity was reported at full conversion, an assessment of the kinetics needing partial conversion is missing. This is important to truly compare the performance of different catalysts. In the present work, a proper protocol was developed to determine the kinetics of catalysts based on chemical reaction engineering study. The protocol was applied for evaluating the kinetics of several type of Co-N-C catalysts which were synthesized through different routes. This kinetic assessment was also used as the basis for a true stability investigation. The Co-N-C catalysts were synthesized through different impregnation procedures prior to pyrolysis at 700-800 °C under inert conditions. The catalytic activity was tested in a benchmark reaction of direct oxidative esterification of benzyl alcohol. The reaction was carried out in a semi-batch of slurry reactor and with continuously bubbling air at operating temperature of 60 °C. A smaller scale set-up of slurry reactor with gas simply pressed up was used for orientation studies but showed gas-phase mass transfer limitations. For the kinetic investigation it was ensured to operate in the kinetically controlled regime without mass transfer limitations. The result shows a simplified first order power law model with the optimum parameters were in a good agreement with the experimental data. As kinetic description, a consecutive reaction from benzyl alcohol to benzaldehyde and then methyl benzoate described with first order power law kinetics proofed to be efficient. All the investigated catalysts show high selectivity towards the ester product. The study shows that the first reaction step towards benzaldehyde is in minimum one magnitude slower compared to the consecutive reaction to methyl benzoate. Strong activity differences of nearly one order of magnitude can be observed for all the investigated catalysts, while a polyaniline derived catalyst employing an additional acid leaching, shows the highest activity. The catalyst stability was evaluated, showing strong dependency of catalytic activity on the base concentration, however, increasing in the deactivation behavior of the catalyst. Furthermore, base concentration of 5 mol% at sufficient catalyst mass loading was known to drive the reaction rate with less influence of catalyst deactivation. |
||||
Alternatives oder übersetztes Abstract: |
|
||||
Status: | Verlagsversion | ||||
URN: | urn:nbn:de:tuda-tuprints-218697 | ||||
Sachgruppe der Dewey Dezimalklassifikatin (DDC): | 500 Naturwissenschaften und Mathematik > 540 Chemie | ||||
Fachbereich(e)/-gebiet(e): | 07 Fachbereich Chemie 07 Fachbereich Chemie > Ernst-Berl-Institut > Fachgebiet Technische Chemie |
||||
Hinterlegungsdatum: | 11 Aug 2022 09:04 | ||||
Letzte Änderung: | 16 Dez 2022 16:30 | ||||
PPN: | 499070623 | ||||
Referenten: | Etzold, Prof. Dr. Bastian J. M. ; Rose, Prof. Dr. Marcus | ||||
Datum der mündlichen Prüfung / Verteidigung / mdl. Prüfung: | 20 Juni 2022 | ||||
Export: | |||||
Suche nach Titel in: | TUfind oder in Google |
Frage zum Eintrag |
Optionen (nur für Redakteure)
Redaktionelle Details anzeigen |