The catalytic pathway characteristics of a commercially prepared unsulfided Co/MoO3/SiO2-Al2O3 catalyst are investigated in a trickle-bed reactor under typical alkane hydrocracking conditions. A mixed n-C26/n-C28 feed with a mole ratio of 1.6 was used as the primary feed. Reaction selectivity between isomerization and hydrocracking was mapped as a function of conversion and found to be consistent with a bifunctional hydrocracking pathway, with the catalyst exhibiting an imbalance between the metal and acid functions. This contrasts with our previous investigation of this catalyst using n-C16 as feed under similar conditions, where hydrogenolysis was found to be the dominant reactive route. In order to further explore how feed composition alters the reactive characteristics of this catalyst, n-C14 was combined with the n-C26/n-C28 in a 1/3 to 2/3 molar ratio. Under all extents of n-C26/n-C28 conversion, even approaching 100% cracking, the co-fed n-C14 is also found to exhibit only bifunctional hydrocracking characteristics. However, in the absence of n-C26/n-C28, a neat n-C14 is again found to undergo nearly exclusively hydrogenolysis reactions. When neat n-C26/n-C28 is again fed following neat n-C14, exclusively bifunctional hydrocracking behavior was observed with activity and selectivity similar to those exhibited at the beginning of the investigation. We propose that the olefin content of the longer chain components interacts strongly with the cobalt metal surface and suppresses the formation of sites responsible for hydrogenolysis. Evidence that the olefinic content of the longer chain components interferes with the lighter molecule's access to acidic sites would appear to support such a proposal.

Impact of hydrocarbon chain length in shifting from hydrogenolysis to bifunctional hydrocracking over an unsulfided Co/MoO<sub>3</sub>/silica-alumina catalyst

242nd National Meeting (2011)

The official archive and repository for all ACS Meetings & Expositions abstracts and select posters or presentations.

Impact of hydrocarbon chain length in shifting from hydrogenolysis to bifunctional hydrocracking over an unsulfided Co/MoO3/silica-alumina catalyst

Impact of hydrocarbon chain length in shifting from hydrogenolysis to bifunctional hydrocracking over an unsulfided Co/MoO₃/silica-alumina catalyst