The Role of Acidity in Terephthalic Acid Synthesis from Renewable Carbon Source

Abstract

AbstractIn this study, manganese‐cobalt (MnCo) mixed oxide catalysts were prepared by two different routes: co‐precipitation and citrate method. The structures and properties of the mixed oxide catalysts were investigated by several techniques: nitrogen adsorption‐desorption isotherms, X‐ray diffraction, X‐ray photoelectron spectroscopy, SEM, FTIR and UV‐Vis spectroscopies, temperature‐programmed reduction with H2 (H2‐TPR) and temperature‐programmed desorption of NH3 (NH3‐TPD). Their catalytic performance was investigated in the liquid‐phase selective oxidation of naturally occurred p‐cymene to terephthalic acid, as an alternative to p‐xylene, a fossil derivative fuel component. Within this study, we demonstrate that the materials prepared by the co‐precipitation method present strong acid sites that boost the oxidation rate and allow oxidation of p‐cymene up to terephthalic acid. The co‐existence of a significant number of strong acid and centers in higher oxidation state (Co3+) are required for these materials to be selective.