Collaborative Research Centre 546
"Structure, Dynamics and Reactivity of Aggregates of Transition Metal Oxides"
Project B3
General information
| Title: |
Dehydrogenation and partial oxidation of short alkanes
|
| Research areas: |
Heterogeneous
catalysis
|
Leader:
|
Dr. Uwe Dingerdissen
Institut für Angewandte Chemie Adlershof e.V.
Richard-Willstätter-Str.12
12489 Berlin
Telefon: 030 6392 4444
Telefax: 030 8413 4454
E-Mail-Adresse: dingerdissen@aca-berlin.de
|
Dr. Evgenii Kondratenko
Institut für Angewandte Chemie Adlershof e.V.
Richard-Willstätter-Str.12
12489
Berlin
Telefon: 030 6392 4448
Telefax: 030 8413 4454
E-Mail-Adresse: evgenii@aca-berlin.de |
Abstract:
During the previous period, it was shown
that higher propene selectivity in the oxidative dehydrogenation of propane
(ODP) over differently structured VOx species is achieved with N2O
as compared to O2 at similar degrees of C3H8
conversion. The positive effect of N2O is related to the inhibition
of direct C3H8 oxidation and also
the consecutive oxidation of C3H6
to COx. The catalytic activity is, however, lower in the presence
of N2O as compared to O2. This is due to the weaker oxidizing
potential of N2O relative to O2 for the re-oxidation of the reduced
surface VOx sites during the ODP reaction.
In order to further elaborate on the influence of oxidizing agent on certain
reaction pathways, the developed methodology should be applied for other catalytic
transformations (dehydrogenation, O-insertion and C-C-splitting) of C2-C4 hydrocarbons
over more complex catalytic V-Me-Ox (Me=, Te, Mo, Nb) systems. The
main aim of the project is to couple mechanistic knowledge of vanadium-catalyzed
reactions and structural catalyst characteristics with macroscopic observations
in chemical reactor. This knowledge is of highly importance for catalyst or
process design.
In order to achieve the above aim, the following strategy will be applied: i)
monitoring of catalyst preparation, ii) characterization of catalytic materials
under working conditions in particular combining several in-situ techniques
to extend the information potential; iii) elucidation of mechanistic and kinetic
aspects of heterogeneous reaction steps via steady-state and transient (temporal
analysis of products reactor and steady-state isotopic transient kinetic analysis)
analysis. A particular attention will be paid to understanding the effect of
support on structure, distribution, reactivity and selectivity of VOx
species in the oxidative dehydrogenation of propane. The structural information
will be obtained in close cooperation with projects B1 and B2. Performance of
real catalysts in the ODP reaction will be compared with those obtained for
thick vanadia films (project C1) and for well-defined model VOx species
over various supports (project B1). In order to derive a comprehensive picture
of the catalyst, catalyst preparation will be monitored using in-situ UV/Vis
analysis both of solutions of single components and calcination procedure.
Publications