Cr doped MCM-41 nanocomposites: an efficient mesoporous catalyst facilitating conversion of toluene to benzaldehyde, an industrial precursor

In this study, toluene, a hazardous organic compound is being converted to benzaldehyde, which has wide applications in food and dye industries. In order to achieve better conversion efficiency, Cr incorporated MCM-41 systems were used. The incorporated systems were synthesized via in situ and wet impregnation methods. The obtained samples have been characterized by Fourier Transform Infra-red, Small angle X-ray Diffraction, Wide angle X-ray diffraction, Scanning Electron Microscopy and UV-Vis Spectroscopy. FTIR spectroscopy showed the bond characteristics in the prepared nanocomposites. X-ray diffraction (XRD) pattern and UV-Visible spectra showed the presence of Cr in MCM-41 framework. Nuclear Magnetic Resonance (NMR) confirmed the conversion of toluene to benzaldehyde. Pore volume and average pore diameter (BET-BJH analysis) was estimated using Surface Area Analyzer. 97.19% conversion of toluene to benzaldehyde was achieved in 18 h using Cr-MCM-41 synthesized via in situ method having Cr/Si ratio as 0.033 as compared to Chromium oxide nanoparticles which took 36 h for 85.2% conversion. The Cr-MCM-41 prepared by wet impregnation method also showed 95% toulene to benzaldehyde conversion, but the time taken by reaction was 36 h.