Effect of the reaction temperature and hydrocarbon partial pressure on the activity of carbon-modified MoO3 for n-hexane isomerization

The isomerization of n-hexane on MoO3 leads to the formation of a new catalytically active phase, molybdenum oxycarbide, that exhibits high and stable activity and isomer selectivity with time on stream under soft reaction conditions. The study as a function of the reaction temperature shows that too low a temperature prevents the MoO3 transformation, while too high a temperature prevents the development of the MoOxCy phase to the benefit of a surface carbide phase. For variable n-hexane partial pressure the same trend is observed with the appearance of carbonaceous and carbide species with higher partial pressure, which are not active for the isomerization.