Toluene oxidation by hydrogen peroxide at elevated temperature over modified TS-1

Abstract

This research studies the oxidation of toluene by hydrogen peroxide using titanium silicalite-1 catalysts modified with different amount of Al at the reaction temperatures higher than the boiling point of water at atmospheric pressure. All catalysts are characterized by X-ray Fluorescence Spectroscopy (XRF), X-ray Diffractometer (XRD), Fourier Transform Infrared Spectrometer (FT-IR), nitrogen adsorption (Brunauer-Emmett-Teller - BET) and Temperature Programmed Desorption of ammonia (NH3-TPD). The parameters studied in this work are amount of aluminium, reaction temperature and hydrogen peroxide per toluene molar ratios. This study found that the addition of Al into TS-1 does not destroy the structure of TS-1. Furthermore, addition of Al promotes the formation of benzaldehyde. All modified catalysts yield benzaldehyde as the major product with a small amount of o-cresol and p-cresol as by-products. The experimental results also show that increasing of the reaction temperature increases the reaction rate. However, the conversion of H2O2 may increase only slightly or decreases in some cases. In addition, increasing molar ratio of H2O2 per toluene increases benzaldehyde formation.