活性炭载铁催化剂作用下几种典型芳烃一步氧化羟基化反应研究

Direct Catalytic Hydroxylation of Several Typical Aromatic Compounds over Fe/Activated Carbon Catalyst

Fe/activated carbon was found to be catalytically effective for the one-step hydroxylation of several typical substituted aromatic compounds under milder reaction conditions(303 K,atmospheric pressure). It was found that the ring oxidation is predominant for all the substrates studied and the selectivity to ring oxidation was much greater than those reported previously.A comparison of the conversions with that of benzene revealed that electron-donating substituents increase the conversions of the substrates,while electron-withdrawing substituents decrease the conversions.The formation of o-and p-hydroxylated products for electron-donating substituted aromatic compounds and o-,m-,p-hydroxylated products for electron-withdrawing substituted aromatic compounds revealed an electrophilc mechanism.The predominant selectivity to o-hydroxylated products for the aromatic compounds with substituents which could coordianated with Fe also shows a new mechanism.This coordianation was affected by the steric hindrance of the substituents.The latter mechanism was also confirmed by DFT method.