TY - JOUR A1 - Roduner, E. A1 - Kaim, W. A1 - Sarkar, B. A1 - Urlacher, V.B. A1 - Pleiss, J. A1 - Gläser, R. A1 - Einicke, W.-D. A1 - Sprenger, G.A. A1 - Beifuß, U. A1 - Klemm, E. A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Hsu, S.-F. A1 - Plietker, B. A1 - Laschat, s. T1 - Selective catalytic oxidation of C-H bonds with molecular oxygen N2 - Although catalytic reductions, cross-couplings, metathesis, and oxidation of C=C double bonds are well established, the corresponding catalytic hydroxylations of C–H bonds in alkanes, arenes, or benzylic (allylic) positions, particularly with O2, the cheapest, 'greenest', and most abundant oxidant, are severely lacking. Certainly, some promising examples in homogenous and heterogenous catalysis exist, as well as enzymes that can perform catalytic aerobic oxidations on various substrates, but these have never achieved an industrial-scale, owing to a low space-time-yield and poor stability. This review illustrates recent advances in aerobic oxidation catalysis by discussing selected examples, and aims to stimulate further exciting work in this area. Theoretical work on catalyst precursors, resting states, and elementary steps, as well as model reactions complemented by spectroscopic studies provide detailed insight into the molecular mechanisms of oxidation catalyses and pave the way for preparative applications. However, O2 also poses a safety hazard, especially when used for large scale reactions, therefore sophisticated methodologies have been developed to minimize these risks and to allow convenient transfer onto industrial scale. KW - Coupling reactions KW - Feedstocks KW - Hydroxylation KW - Molecular oxygen KW - Oxidation KW - Catalytic oxidation KW - Micro reactor KW - Explosion KW - Safety PY - 2013 DO - https://doi.org/10.1002/cctc.201200266 SN - 1867-3880 VL - 5 IS - 1 SP - 82 EP - 112 PB - Wiley-VCH CY - Weinheim AN - OPUS4-27637 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Lange, T. A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Reaction engineering investigations of the partial oxidation of o-xylene in the explosion regime - microfixed bed versus catalyst coating N2 - The selective gas phase oxidation of o-xylene was investigated inside of the explosion regime using a microstructured reactor. The V2O5/TiO2 catalyst was used as microfixed bed and as catalyst coating. There were no significant losses of the selectivity to phthalic anhydride with feed compositions up to 7 vol % o-xylene observable. Above 7 vol % the selectivity decreased due to total oxidation, especially for the microfixed bed, which was probably caused by a hotspot. KW - Catalysis KW - Microreactors KW - Partial oxidation KW - Xylene KW - o-Xylene KW - Explosion regime PY - 2013 DO - https://doi.org/10.1002/cite.201200197 SN - 0009-286X SN - 1522-2640 VL - 85 IS - 4 SP - 461 EP - 466 PB - Wiley-VCH Verl. CY - Weinheim AN - OPUS4-30298 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Lange, T. A1 - Neher, F. A1 - Klemm, E. A1 - Heinrich, Sebastian A1 - Balcazar Pust, Emilio A1 - Liebner, Christian A1 - Hieronymus, Hartmut T1 - Heterogeneous catalysis meets micro reactors: Partial oxidations in the explosion regime N2 - Investigations on primary, secondary and tertiary explosion protection have been performed for micro reactors with slit-like channels which are coated with catalyst. Ethene/oxygen mixtures have been used as model gas mixtures representing explosion group IIB (DIN EN ISO 16852). It could be shown that the explosion regime can be significantly reduced when using micro reactors (primary explosion protection). Furthermore, safe Operation inside the explosion regime is possible with micro reactors (secondary explosion protection), but, at certain conditions thermal runaway and ignition of detonations are possible. An unexpected behaviour has been found, because thermal runaway occurred when Volumetrie flow rate was increased. This behaviour is completely opposite to that of multi tube fixed bed reactors which show an increase of safety when increasing volumetric flow rate. Micro reactors can be constructed pressure-resistant even when detonations occur inside (tertiary explosion protection). For the example of o-xylene oxidation it could be shown that space time yield can be increased significantly when entering explosion regime. T2 - DGMK International conference - Selective oxidation and functionalization: Classical and alternative routes and sources CY - Berlin, Germany DA - 13.10.2014 PY - 2014 SN - 978-3-941721-44-9 VL - 2014-3 SP - 97 EP - 105 AN - OPUS4-31759 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Heinrich, Sebastian A1 - Edeling, Florian A1 - Lange, T. A1 - Klemm, E. ED - Beyer, M. ED - Stolz, T. T1 - Zündung, Ausbreitung und Unterdrückung von Explosionen in einem Mikroreaktor N2 - Der vorliegende Beitrag behandelt spezifische Aspekte der Sicherheitstechnik bei heterogen katalysierten Oxidationsreaktionen. Ergebnisse von Explosionsuntersuchungen an Ethen-Sauerstoffgemischen in einem kontinuierlich betriebenen Mikroreaktor, die beispielsweise für den Ethylenoxidprozess relevant sind, werden vorgestellt. Der Anfangsdruck der untersuchten Eduktgemische lag zwischen 1000 hPa und 10000 hPa bei Anfangstemperaturen zwischen Umgebungstemperatur und einer Temperatur bis zu 673 K. Mikrostrukturierte Reaktoren bieten einen erweiterten Bereich von Betriebsbedingungen. Die Untersuchungen zielen auf den sicheren Betrieb eines Mikroreaktors bei Bedingungen, die bei konventionellen Reaktoren als innerhalb des Explosionsbereichs eingestuft werden, ab. In bestimmten Grenzen kann eine Unterdrückung von Explosionen in einem Mikroreaktor erreicht werden. Es ist jedoch nicht möglich, einen Mikroreaktor unter allen Bedingungen sicher zu betreiben. Aus diesen Gründen wurde die Explosionsausbreitung durch einen mikrostrukturierten Reaktor hindurch und die Zündung einer Gasphasenexplosion durch Hot-Spots in dem Reaktor untersucht. Die angewandten Untersuchungsmethoden sind Gegenstand aktueller Normungsaktivitäten. T2 - 13. BAM-PTB-Kolloquium zur chemischen und physikalischen Sicherheitstechnik CY - Braunschweig, Germany DA - 18.06.2013 KW - Micro Reactor KW - Explosion KW - Safety PY - 2013 SN - 978-3-95606-062-5 DO - https://doi.org/10.7795/210.20130910K SN - 1868-5838 SP - 90 EP - 98 AN - OPUS4-29849 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Balcazar Pust, Emilio A1 - Neher, F. A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Determination of ignition temperature in micro reactors N2 - Explosion protection of oxidation reactions in micro reactors was investigated. Lange et al. (2014) reported on the possibilities of operating oxidation reactions in catalyst coated micro reactors within the explosion regime, but also warned about hotspot induced thermal runaway and detonation ignition at certain conditions. Methane and ethene, representing the explosion groups IIA1 and IIB (DIN EN ISO 16852), were used in stoichiometric oxygen mixtures with respect to total oxidation, which represents the worst case scenario in terms of safety assessment. Using laser radiation on a ceramic target inside of the micro channel, an artificial, controllable hotspot was generated. The ignition temperatures of fuel gas/oxygen mixtures inside a micro reactor were measured and their dependencies on initial pressure, initial temperature, volumetric flow rate, and micro channel height were examined. Deflagration reactions prior to the detonation were observed for the first time inside a micro reactor. KW - Explosion safety KW - Explosionsschutz KW - Zündtemperatur KW - Mikroverfahrenstechnik KW - Thermisches Durchgehen KW - Micro process engineering KW - Autoignition temperature KW - Hotspot KW - Thermal Runaway PY - 2016 DO - https://doi.org/10.3303/CET1648092 SN - 2283-9216 SN - 1974-9791 VL - 48 SP - 547 EP - 552 PB - AIDIC CY - Milano AN - OPUS4-34164 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - CONF A1 - Klemm, E. T1 - Partielle Gasphasenoxidationen im Explosionsbereich mittels Mikroreaktionstechnik T2 - Arbeitsausschuss Mikroreaktionstechnik CY - Frankfurt am Main, Germany DA - 2009-01-21 PY - 2009 AN - OPUS4-18732 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Fischer, J. A1 - Klemm, E. T1 - Untersuchungen zur Explosionsausbreitung in mikrostrukturierten Reaktoren T2 - 12. Kolloquium zu Fragen der chemischen und physikalischen Sicherheitstechnik CY - Berlin, Deutschland DA - 2010-06-15 KW - Deflagration KW - Detonation KW - Mikroreaktionstechnik KW - Mikroreaktor KW - Sicherheitstechnik PY - 2010 SN - 978-3-9813550-1-7 SN - 0938-5533 SP - 7 EP - 10 PB - BAM Bundesanstalt für Materialforschung und -prüfung CY - Berlin AN - OPUS4-21495 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Liebner, Christian A1 - Fischer, J. A1 - Hieronymus, Hartmut A1 - Klemm, E. ED - Suter, G. ED - de Rademaeker, E. T1 - Are micro reactors inherently safe? - An investigation of gas phase explosion propagation limits T2 - 13th International symposium on loss prevention and safety promotion in the process industries CY - Brugge, Belgium DA - 2010-06-06 KW - Deflagration KW - Detonation KW - Mikroreaktionstechnik KW - Mikroreaktoren KW - Sicherheitstechnik PY - 2010 SN - 978-90-76019-291 VL - 02 SP - 281 EP - 285 CY - Brugge, Belgium AN - OPUS4-21496 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - GEN A1 - Heinrich, Sebastian A1 - Liebner, Christian A1 - Hieronymus, Hartmut A1 - Klemm, E. T1 - Durchführung heterogen katalysierter Selektivoxidationen im Explosionsbereich unter Einsatz von Mikrostrukturreaktoren T2 - 10. Fachtagung Anlagen-, Arbeits- und Umweltsicherheit CY - Köthen, Deutschland DA - 2010-11-04 KW - Mikroreaktor KW - Oxidation KW - Explosion PY - 2010 SN - 978-3-89746-119-2 IS - P-03 SP - 1 EP - 6 CY - Frankfurt/M. AN - OPUS4-22359 LA - deu AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER - TY - JOUR A1 - Heinrich, Sebastian A1 - Plettig, M. A1 - Klemm, E. T1 - Role of the Ti(IV)-superoxide species in the selective oxidation of alkanes with hydrogen peroxide in the gas phase on titanium silicalite-1: an in situ EPR investigation N2 - The interaction of TS-1 with gaseous hydrogen peroxide at temperatures above 373 K has been investigated by in situ EPR measurements. Treatment of TS-1 with hydrogen peroxide in the gas phase leads to a strong EPR signal, assigned to the Ti(IV)-superoxide species. In contrast to investigations with liquid hydrogen peroxide, here only one Ti(IV)-superoxide species could be detected in the EPR spectrum. The time constant of the reaction of the Ti(IV)-superoxide species detected by in situ EPR measurements was much larger than that observed for the rate of consumption of propane or propene via gas chromatographic analysis. Thus, we conclude that the Superoxide species may take part in the oxidation reaction (via side reactions or the formation of unselective products), but is probably not the main responsible species in the oxidation of propane or propene. KW - Titanium silicalite-1 KW - EPR KW - Oxidation KW - Hydrogen peroxide KW - Superoxide KW - Alkanes PY - 2011 DO - https://doi.org/10.1007/s10562-010-0534-6 SN - 1011-372X VL - 141 IS - 2 SP - 251 EP - 258 PB - Kluwer CY - Dordrecht AN - OPUS4-23553 LA - eng AD - Bundesanstalt fuer Materialforschung und -pruefung (BAM), Berlin, Germany ER -