Two microporous carbon molecular sieve(CMS)samples with different surface properties were obtained from a commercial CMS through deashing treatment(C1)and then oxidation(C2)by 30%H2O2 solution.Both the two samples were characterized by acidic/basic titration,N2 adsorption isothermal(BET),point of zero charge(pHPZC).Decomposition of H2O2 in dilute unbuffered solution was carried and the evolved oxygen was measured volumetrically.After oxidation,the surface acidity and total surface oxygen-containing groups increased,while the special surface area and total pore volume slightly decreased.The experimental results showed that the H2O2 decomposition reaction on CMS obeyed the first-order kinetic.The activation energy(Ea)of the decomposition reaction on oxidized CMS increase from 33.3(C1)to 45.5(C2)kJ.mol-1,however the negative value of activation entropy of the reaction(ΔS≠)decreased from-197(C1)to-159(C2)J.mol-1.K-1 calculated by transition state theory.
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.
