The main objective of the present work was to study the influence of the use of solvent in the catalytic performance of metal-incorporated MCM-41 in liquid phase oxidation of benzyl alcohol, using aqueous TBHP as oxidant. The catalysts were prepared by a precipitation method at room temperature, where the metal precursors (aqueous solutions of NH4VO3 and CeCl3.6H2O for V-MCM-41 and Ce-MCM-41) were added simultaneously with the Si precursor at a molar ratio of Si/M = 25. A MCM-41 sample without any modification was also prepared for comparision. XRD analyses showed that all catalysts possess MCM-41 structure, although the metal incorporation leads to partial loss of the hexagonal mesophase. FTIR spectra of the modified samples showed the typical vibrational modes for SiO2 and isomorphous substitution was observed by displacement of the νas and νs Si-O-Si, when compared to Si-MCM-41. UV-Vis diffuse reflectance data indicates that the metal species are highly dispersed in the structure of the materials. The catalytic tests revealed that the modified samples present activity towards liquid phase oxidation, especially V-MCM-41 sample. By using CH3CN as solvent in the reaction, there was a considerable increase in benzaldehyde selectivity with little or no effect in the yield for the same product. This indicates that the solvent has a positive effect in turning this chemical process more specific towards the desired product. This can be due to a controlling effect of the solvent in the abstraction of α-hydrogens in benzyl alcohol or in the radical species that are formed in the medium.

Solvent effect in the efficiency of V- and Ce-incorporated MCM-41 for liquid phase oxidation of benzyl alcohol

256th National Meeting (2018)

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