Studies On The Liquid-phase Selective Oxidation Of Toluene With Hydrogen Peroxide And The Synthesis Of Natural Benzaldehyde

One of the oxidation products of tolunene is benzaldehyde which is an important intermediate in organic synthesis industry. At present, benzaldehyde is obtained from chlorination of toluene followed by hydrolysis. This process can cause environment pollution and corrosion of equipment. Liquid-phase oxidation of toluene which can give high yieids is a mildly route, so it is drawing much attention. In addition, with the development of the living standards, the growing demand for benzaldehyde in high quality brings new challenges for the manufacturing process. In this paper, we focused on the following aspects.(1) A series of MxOy/HMS catalysts were prepared for oxidation of toluene with hydrogen peroxide. The catalysts were characterized by XRD, FT-IR, TEM and Nitrogen adsorption method. Effects of MxOy loading and chromium source on the reaction were investigated. The best catalytic performances can be obtained when dodecylamine was used as templating surfactant and chromium nitrate as chromium source.(2) According to the above,15%Cr2O3-HMS catalysts were prepared for oxidation of toluene. The results showed that under optimal conditions:catalyst0.5g, co-catalyst0.1g, H2O212mL, solvent15mL 90℃for4h, the conversion of toluene can reach23.8%and the selectivity for benzaldehyde up to38.4%. We can improve the selectivity of benzaldehyde when we use V-HMS as carrier.(3) A clean process to produce benzaldehyde from the oxidation of cinnamaldehyde with polyethylene glycol as transfer catalyst has been devoted in this paper. The optimal experimental conditions are as follows: cinnamaldehyde1mmol, polyethylene glycol0.02g, NaHCO30.035g, H2O22mL,50℃for4h, and the conversion of cinnamaldehyde can reach98.4%and the selectivity for benzaldehyde up to69.6%.