Combined acid additives and the MC catalyst for the autoxidation of p-xylene to terephthalic acid

The autoxidation of p-xylene was carried out with the Co(OAc)2/Mn(OAc)2/Br− catalyst in the presence of acid additives, such as trifluoroacetic acid (TFA), heptafluorobutytic acid (HFBA) and p-toluenesulfonic acid. All the acid additives at low concentrations significantly improved the effectiveness of the catalyst. Under comparable reaction conditions and time, HFBA gave a 15% higher yield of terephthalic acid than TFA.