Infrared Spectroscopy Characterization of the Chemistry of C<sub>4</sub> Hydrocarbons on Pt(111)
Single-Crystal Surfaces
Ilkeun Lee
Francisco Zaera
10.1021/jp0724830.s001
https://acs.figshare.com/articles/journal_contribution/Infrared_Spectroscopy_Characterization_of_the_Chemistry_of_C_sub_4_sub_Hydrocarbons_on_Pt_111_Single_Crystal_Surfaces/2996932
The uptake and thermal chemistry of a number of C<sub>4</sub> hydrocarbons on Pt(111) single-crystal surfaces were
characterized by reflection−absorption infrared spectroscopy (RAIRS). The compounds studied include butane,
1-butene, <i>cis</i>-2-butene, <i>trans</i>-2-butene, and 1,3-butadiene as well as 1-iodobutane, 2-iodobutane, 1-bromo-2-butene, and 1-bromo-3-butene, precursors for the formation of corresponding alkyl and alkenyl intermediates.
Much of the chemistry reported here agrees with previous work on similar systems, and conforms with the
general idea of hydrogenation, dehydrogenation, and H−D exchange reactions occurring by single hydrogen
incorporation and elimination steps according to the so-called Horiuti Polanyi mechanism. In addition, though,
a couple of surprising observations are presented of particular relevance to the mechanism of carbon−carbon
double bond isomerizations. In particular, it was seen that although the isomerization of <i>trans</i>- to <i>cis</i>-2-butene is more favorable and occurs at lower temperatures than the reverse cis-to-trans conversion, β-hydride
elimination from the common 2-alkyl intermediate produces <i>trans</i>-2-butene preferentially. This indicates that
it is the relative adsorption energy of the alkene what determines selectivity in these reactions.
2007-07-12 00:00:00
iodobutane
C 4 Hydrocarbons
Infrared Spectroscopy Characterization
tran
Pt
hydrogen incorporation
elimination steps
alkyl
ci
alkenyl intermediates
Horiuti Polanyi mechanism
bond isomerizations
C 4 hydrocarbons
adsorption energy
bromo
RAIRS