Studies On The Aerobic Oxidation Of P-methyl Anisole To P-anisaldehyde Catalyzed By Metal Porphyrins/metal Salts

p-Anisaldehyde is an important organic synthesis intermediate, which has been widely used in most fields. Recently, due to the cheap and readily available properties, p-methylanisole was exploited as raw material to synthesize the p-anisaldehyde based on one-step oxidation reaction, and the synthetic method has attracted increasing research attention in recent years. However, this method is limited by its undesirable energy consumption and the yielded serious environmental pollution. Metal porphyrins can simulate the structure and function of cytochrome P-450, which can activate molecular oxygen under mild conditions to avoid these problems. Therefore, metal porphyrins were exploited as the catalysis to catalyze the reaction of p-methylanisole to p-anisaldehyde with O2 as the oxidizing agent. The detailed investigations are as following:?1? Firstly, we explored the influence and variation of metal porphyrins/metal salts composite system catalyst for the oxidation reaction results of p-methylanisole. Study for the catalytic of metal porphyrins of different central metal ions. The order of catalytic activity shows that cobalt porphyrin > iron porphyrin > manganese porphyrin; selectivity order shows that cobalt porphyrin >manganese porphyrin >iron porphyrin; the different substituents cobalt porphyrins, T?p-Cl?PPCoCl of the catalytic activity is best, the highest yield of 19.1%; the best catalytic activity of different metal salts is Mn?OAc?₂·4H₂O, the highest yield of 9.6%; the best catalytic activity of metal porphyrins/ metal salts composite catalysis is T?p-Cl?PPCoCl and Mn?OAc?₂·4H₂O, the highest yield is 21.6%;the best ratio between the metal porphyrins/metal salts of the composite catalyst system is 1:1, the highest yield of 21.6%.?2? Secondly, we discuss the various reaction conditions on p-methylanisole for the oxidation reaction results of the impact and summarize the rusults of its variation, obtained the optimum reaction conditions. It shows that when we using acetonitrile as solvent, the concentration of the p-methylanisole is 2.0 mol/L, the amount of the T?p-Cl?PPCoCl and Mn?OAc?₂·4H₂O were 0.05 mmol/L, the reaction temperature is 90 oC, the reaction pressure is 0.4 MPa, the reaction time is 8 h, the catalytic activity is best. Under these reaction conditions, the conversion of p-methylanisole is 38.8% and the selectivity of p-anisaldehyde is 55.6%.