Investigation of suitable precursors for manganese oxide catalysts in ethyl acetate oxidation.

The control of ethyl acetate emissions from fermentation and extraction processes in the pharmaceutical industry is of great importance to the environment. We have developed three MnO catalysts by using different Mn precursors (MnCl, Mn(CHCOO), MnSO), named as MnO-Cl, -Ac, -SO. The tested catalytic activity results showed a sequence with Mn precursors as: MnO-Cl > MnO-Ac > MnO-SO. The MnO-Cl catalyst reached a complete ethyl acetate conversion at 212℃ (75℃ lower than that of MnO-SO), and this high activity 100% could be maintained high at 212℃ for at least 100 hr. The characterization data about the physical properties of catalysts did not show an obvious correlation between the structure and morphology of MnO catalysts and catalytic performance, neither was the surface area the determining factor for catalytic activity in the ethyl acetate oxidation. Here we firstly found there is a close linear relationship between the catalytic activity and the amount of lattice oxygen species in the ethyl acetate oxidation, indicating that lattice oxygen species were essential for excellent catalytic activity. Through H temperature-programmed reduction (H-TPR) results, we found that the lowest initial reduction temperature over the MnO-Cl had stronger oxygen mobility, thus more oxygen species participated in the oxidation reaction, resulting in the highest catalytic performance. With convenient preparation, high efficiency, and stability, MnO prepared with MnCl will be a promising catalyst for removing ethyl acetate in practical application.