The Research On The Selective Oxidation Of Toluene By Metalloporphyrins/NHPI

The oxidation process of toluene is an extremely important reaction in chemical industry. The major products, benzaldehyde, benzyl alcohol and benzoic acid are widely used in pharmaceutical, dyestuff, perfumary, resin and textile fiber industries. At present, benzaldehyde and benzyl alcohol are mostly obtained by toluene side chain chlorination hydrolysis method. the complex process discharges massive pollutant such as HCl gas and heavy metal salts, In this paper, we combined metalloporphyrin and NHPI to constitute a biomimetic oxidation system and investigated the catalytic performance in the selective oxidation of toluene by dioxygen under mild conditions. To the best of our knowledge, it is the first time to use this catalytic system for toluene oxidation. It shows that this method of synthesizing benzaldehyde and benzyl alcohol is very effective, and the catalytic reaction is controllable and environmental friendly.The details are summarized as follows:1. Firstly, the synthetic methods of various simple metalloporphyrins were introduced. The structure of various metalloporphyrins were characterized by MS, 'RNMRH, IR and UV-Vis.2. Secondly, a new gas chromatography method for analysis benzaldehyde, benzyl alcohol and benzoic acid was developed. The method was Internal-Standardization on column of PEG-20000. The proposed method has the advantages of high sensitivity, brilliant selectivity, good accuracy, simplicity and rapidity.3. Thirdly, The paper reported the investigation of the effects of reaction conditions, such as temperature, amount of catalyst, flow of oxygen and concentration of toluene.And the catalytic activities of various metalloporphyrins were also studied, which were in the order of T(p-Cl)PPCo >T(p-Cl)PPMnCl> T(p-Cl)PPCu> (T(p-Cl)PPFe)2O.4. We compared the system of Co(OAc)₂/NHPI with the system of T(p-Cl)PPMnCl/NHPI, also compared these systems on the point of the selectivity and the variety of the productions content.5. Finally, on the basis of the well studied mechanism of Co(AcO)2/NHPI and hemin/NHPI, a possible reaction mechanism was proposed on the basis of our study and references.