Kinetics of dehydrogenation of n-octane on a promoted Pt-catalyst

Titelangaben

Prucker, Tobias ; Lamberty, Aliena ; Thiessen, Johannes ; König, Matthias ; Jess, Andreas:
Kinetics of dehydrogenation of n-octane on a promoted Pt-catalyst.
In: Chemical Engineering Journal. Bd. 442, Part 2 (2022) . - 136233.
ISSN 1385-8947
DOI: https://doi.org/10.1016/j.cej.2022.136233

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Abstract

In contrast to short as well as long chain paraffin dehydrogenation, the highly desirable reaction of intermediate chain length paraffins (C6 - C9) to the corresponding linear monoolefins receives only little attention in the literature. Consequently, the dehydrogenation of the model substance n-octane on promoted platinum catalysts was studied thoroughly. In the first instance, the effect of the addition of different promotors (Sn, K, Ce) on the catalytic performance with emphasis on activity and octene selectivity was tested by screening of 16 differently promoted Pt-catalysts. The optimized and non-deactivated catalyst was then used to investigate the kinetics of n-octane dehydrogenation including the unwanted consecutive formation of n-octadienes and C8-aromatics. The analysis revealed that the desired n-octenes are rapidly converted to n-octadienes, i.e. the thermodynamic equilibrium of this reversible reaction is quickly established. To a small extent, the n-octadienes are further converted to C8-aromatics. A kinetic model was developed, which also considers the inhibiting effect of n-octenes on the rate of n-octane conversion. The model accurately predicts the formation of mono- and diolefins as well as of aromatics in the initial reaction phase in the absence of deactivation.