The synthesis of terephthalic acid from biomass remains an unsolved challenge. In this study, we conducted the selective oxidation of p-cymene (synthesized from biodegradable terpenes, limonene, or eucalyptol) into terephthalic acid over a Mn-Fe mixed-oxide heterogeneous catalyst. The impact of various process parameters (oxidant, temperature, reaction time, catalyst amount, oxygen pressure) on the selectivity to terephthalic acid was evaluated, and some mechanistic aspects were elucidated. An unprecedented synthesis of biobased terephthalic acid (51 % yield) in the presence of O2 is reported.
Keywords: carboxylic acids; heterogeneous catalysis; iron; manganese; oxidation.
© 2016 Wiley-VCH Verlag GmbH & Co. KGaA, Weinheim.