Mechanism of carbon-nitrogen bond scission in the presence of H2S on Pt Supported catalysts

The reactivity of a series of amines with various structures and different numbers of hydrogen atoms on the carbon atoms in the α and β position was used to evidence the C–N bond scission mechanism in the presence of H2S on Pt based catalysts (deposited on alumina, zirconia and silica–alumina) and compare it with the mechanism on a NiMoP on alumina sulfide catalyst. The effect of the H2S partial pressure was also checked. Catalytic activities (amine overall conversion, C5 hydrocarbon formation, and amine disproportionation) deeply depend on the structure of the N-containing molecule. Tert-pentylamine is the most reactive molecule for sulfide catalysts whereas, in the case of n-pentylamine, Pt on zirconia was found to be the most efficient for C–N bond breaking. Such properties cannot be related to the acidic properties of the support but to a unique support–metal interaction, since alumina or silica–alumina supported platinum catalysts do not present this behaviour.