Proton magnetic resonance thermal analysis of petroleum derived asphaltene with Co smectite and CoMo alumina based catalysts

The catalytic transformation of petroleum-derived asphaltene with Co loaded smectite and CoMo loaded alumina based catalysts was studied in the range of 40°-420°C using proton magnetic resonance thermal analysis. Residual H₂ as qualitative measure of the hydrogen remaining in the sample and second moment (M_2T16) sensitive to molecular mobility were obtained as a function of temperature. Both residual H₂ and M_2T16 of the asphaltene depend on the properties of the coexisting catalyst. Metal oxides in the Co porous saponite and CoMo alumina based catalysts, active for transformation of asphaltene, were probably reduced to the metals and became ferromagnetic at 350°C, because the M_2T16 values of the char derived from the asphaltene with the active catalysts after cooling to room temperature were > 250 kHz², compared to typical values of 150 kHz² for char without ferromagnetic material. HDS and hydrocracking with the catalysts were correlated with the values of M_2TT16 at 400°C. Moderate interaction of metal oxide with support material resulted in an intermediate reduction state with high HDS activity.