[Zurück]

V. Markova, J. Philbin, W. Zhao, A. Genest, J. Silvestre-Albero, G. Rupprechter, N. Rösch:
"Catalytic Transformations of 1-Butene over Palladium. A Combined Experimental and Theoretical Study";
ACS Catalysis, 8 (2018), S. 5675 - 5685.

Applying a density functional approach to slab models of
planar, (111), and rough, (110), Pd surfaces, we determined the isomerization
free energy barriers of 1-butene to be significantly lower than the
hydrogenation barriers. Microkinetic modeling allows one to mirror the
kinetic experiments on conversions of 1-butene at the corresponding singlecrystal
surfaces in a qualitative fashion. Despite the inherent limitations of such
kinetic modeling, theoretical predictions are fully supported by experimental
data using Pd model catalysts: i.e., Pd(111) and Pd(110) surfaces. The
isomerization mechanism was calculated to proceed via an initial dehydrogenation
of 1-butene to 1-buten-3-yl as an intermediatein contrast to the
commonly proposed 2-butyl intermediate, associated with the Horiuti−Polanyi mechanism. Our modeling results rule out the
original assumption that isomerization has to start with a hydrogenation step to rationalize the dependence of isomerization on
hydrogen. However, this hydrogen dependence may arise in the second step, after an initial dehydrogenation, as suggested by the
experimental data under hydrogen-deficient conditions.

palladium, 1-butene, hydrogenation, isomerization, DFT calculations on periodic models, microkinetic modeling

http://dx.doi.org/10.1021/acscatal.8b01013