264
S. Nassreddine et al. / Journal of Catalysis 278 (2011) 253–265
(Fig. 14) that an increase of the acid/metal site ratio (by changing
the metal dispersion or loading) leads to an increase of the selectiv-
ity to ROCPs (and cracking products). In particular, the trends
observed for n-butyl-benzene (major ROP) and branched/multi-
substituted ROPs (Fig. 11) suggest that the former results from
b-scission of a carbenium ion and that the latter are secondary
Brönsted-catalyzed isomerization products. Conversely, the low
variation of the selectivity to nBCH and nPCP indicates that these
(minor) products may be formed by hydrogenolysis of bicyclic
intermediates.
Acknowledgments
S. Nassreddine thanks the French government for his PhD grant.
We thank Sasol Germany GmbH for the supply of the SIRAL-40
sample. P. Delichère, L. Burel, G. Toussaint, C. Lorentz, and N.
Cristin are greatly acknowledged for their support in XPS, TEM,
GCꢀGC–MS, NMR, and ICP-OES analyses, respectively. S. Casu
and J.L. Zotin (Petrobras) are acknowledged for early experiments
and support, respectively.
Our future work, through complementary kinetic experiments
combined to GCꢀGC–MS analysis, will aim at further rationalizing
the observed catalytic trends and proposing a mechanistic reaction
scheme for tetralin hydroconversion on Ir/ASA.
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