n-Octane aromatization on Mo2C-containing catalysts

The reaction pathways of n-octane were studied on various Mo2C-containing catalysts. On unsupported Mo2C prepared by C2H6/H2 gas mixture the reaction of octane started at 573 K, and the conversion reached an initial value of ∼38% at 873 K. At lower temperature, 573–623 K, the main process is the dehydrogenation with some cracking. At 673–873 K, however, aromatics, xylene, toluene, benzene and ethylbenzene also formed with 58–30% selectivity. On Mo2C/Al2O3 the product distribution was different. At 773–823 K the main aromatics were ethylbenzene and o-xylene, they formed with ∼62–51% selectivity at 23–50% conversion. In contrast, on Mo2C/ZSM-5(80), which was found to be the most effective catalyst in the present work, toluene and benzene were the dominant aromatics. This suggests that the occurrence of the hydrogenolysis of C8 aromatics on the acidic sites of ZSM-5. This catalyst exhibited a very stable activity: the conversion decayed only with few percent even after 10 h, and the aromatizing capability also remained high. The results are interpreted by the monofunctional (pure Mo2C) and bifunctional mechanism (supported Mo2C) of the aromatization of n-octane.