Liquid phase oxidation of benzyl alcohol to benzaldehyde over sepiolite loaded chromium oxide catalysts

摘要

Sepiolite loaded chromium oxide catalysts were prepared through the precipitation and characterized by physical techniques such as XRD, SEM, TEM BET, EDS, FT-IR, UV–vis, XPS, H2-TPR… The experimental results indicated that Cr2O3are major Cr-species finely distributed on the sepiolite nanofibers in addition to small amount of Cr(VI) on the catalyst surface. All catalysts have large surface area, high porosity, and good dispersion of Cr2O3nanoxides on the support. The sepiolite-loaded-Cr catalysts have been tested for the partial oxidation of benzyl alcohol without any base or organic solvent and shown good conversion and very high selectivity to benzaldehyde at mild conditions. The catalytic activity was found to be related to the amount of transition metal oxide content, distribution of Cr(III) sites, oxidant behavior, and reaction variables… An increased calcination temperature of the catalysts leads to the distortion of sepiolite fibers, the interaction between Cr(III) and support, and the enhanced reusability of the catalysts.