Effect of in situ addition of Pd in SBA-15 for the deoxygenation of stearic acid

Several mesoporous SBA-15 type supports were synthesized; some of them were modified with an auxiliary organic molecule (SBA-15/TMB). The catalysts were obtained by in-situ addition of Pd (0.5- 3.0 %wt) during supports synthesis. The materials were characterized by Nitrogen physisorption, XRD, SAXS, TPR and SEM. The catalytic activity was tested in the deoxygenation of stearic acid (SA) at 300°C and 20 bar, feeding 0.25 ml/min of SA (4 %wt) in dodecane, and 50 ml/min of H2 (10%volume) in N2. The synthesized solids showed characteristic properties of mesoporous materials, and the organic molecule had an effect of expansion and disordering of the structure of the material, generating increments of the textural properties, while Pd addition did not cause significant changes in the structural properties of these materials. The catalysts showed high initial conversions of SA (40-75%), decreasing to 20-40% after 6 h reaction. Higher content of Pd produced higher conversion of SA and lower catalyst deactivation. Catalysts with TMB were less active. Selectivity to non-oxygenated products was 100% with n-heptadecane as the main product.