Aromatization of n-heptane on Mo2C-containing catalysts

The reaction pathways of n-heptane were studied on various Mo2C-containing catalysts characterized by X-ray photoemission spectroscopy and surface acidity measurements. Unsupported Mo2C catalyzed the dehydrogenation and cracking of n-heptane even at 573-623 K. Above 723 K, the dehydroaromatization of heptane became the dominant route for yielding toluene and benzene, with selectivities of 43 and 8%, respectively, at conversions of 20-23%. The catalytic performance of Mo2C was improved when Mo2C was deposited in a highly dispersed state on various supports, like silica, alumina, and ZSM-5. The best yield of the formation of aromatics (48.7%) was obtained for 5% Mo2C/ZSM-5 (SiO2/Al2O3 = 80) at 873 K. Although the deposition of coke occurred on all samples during the reaction, the latter catalyst underwent only a slight deactivation even after 20 h of reaction. The results obtained were interpreted by the monofunctional (pure Mo2C), and bifunctional mechanism (supported Mo2C) of the aromatization of n-heptane.