Liquid Phase Oxidation Of Alkyl Group On Aromatic Ring

MC method is one of the most important process in the field of petrochemical industry, in which hydrocarbons are oxidized to aldehydes and acids using organic acid as solvent in the presence of catalysts consisting of cobalt acetate,manganese acetate and bromine compound.The liquid phase catalytic oxidation of toluene,cumene and 2,6-DIPN are discussed in this paper.The effects of different solvent,initial concentration,catalyst dosage, catalyst proportion and reaction temperature on the result of oxidation of toluene were analyzed,and kinetic model were carried out.It could be seen from the result that the oxidation rate of toluene didn't vary significantly with the change of toluene concentration, the highest yield of benzaldehyde increased with the decrease of toluene concentration and the increase of catalyst dosage;catalyst proportion had no significant influence on the yield of benzaldehyde,and the oxidation of toluene could be inhibited by increasing Co/Mn;there was no significant difference between the activation energies of toluene and benzaldehyde, and the yield of benzaldehyde could not be improved by changing reaction temperature.As the oxidation process of 2,6-DIPN are difficult,cumene were selected as the model to interpret the oxidation mechanism of isopropyl group.The effects of initial concentration, catalyst dosage and reaction temperature were discussed.Based on this result,an orthogonal experiment was carried out,and the effects of Br,metal ions additives and organic nitrogen compounds on the yield of 2,6-NDCA were discussed.The results shown that influence order for the yield of 2,6-NDCA in the orthogonal experiment were:reaction temperature＞feed flux＞catalyst dosage＞Co/Mn.High temperature could cause the cleavage of naphthalene ring, and low temperature could not give rise to the full oxidation of intermediate products,then the suitable temperature could be 170℃.It is good for producing 2,6-NDCA to decrease the feed flux and increase the catalyst dosage,however there was no significant influence of Co/Mn for the yield of 2,6-NDCA.