Synthesis, Characterization and Application in Friedel-Crafts Reaction of SBA-15 Supported on Carbon Nanofibers Composite (C-NFC)

摘要

The above results clearly show the high performances of nanostructured carbon with hierarchical morphology materials, as compared to those usually obtained with the traditional macroscopic supports. Combination of a nanoscopic and high aspect ratio morphology and the high external surface of these supports rendered them superior in terms of catalytic performance when compared to that obtained on traditional grain shaped catalysts. The coating of SBA-15 on macroscopic bodies, like C-NFC composite, also allows an ease in the catalyst recovery, thus excluding important problems linked with binder use or post-reaction filtration. Cycling tests indicate that deactivation occurs probably due to the gradual plugging of the SBA-15 channel by residual carbonaceous residue. The direct consequence of the channel plugging is the gradual decrease of the para-ketone selectivity due to the lost of the gallium active sites localized within the channel. The macroscopic shaping of the support could allow one to envisage the use of this nano-macro composite catalyst in a fixed-bed configuration instead of batch configuration where deactivation by carbonaceous residues could become significant.