Efficient Synthesis of Cyclohexanol and Ethanol via the Hydrogenation of Acetic Acid-Derived Cyclohexyl Acetate with the CuxAl1Mn2-x Catalysts

The hydrogenation of cyclohexyl acetate (CHA), derived from the esterification of acetic acid and cyclohexene, not only alleviates the overcapacity of acetic acid, but also produces value-added cyclohexanol (CHOL) and ethanol at a low cost. Herein, we prepared Cu1Al1, Cu1Mn1 and CuxAl1Mn2-x catalysts via a deposition-precipitation method for the hydrogenation of CHA to CHOL and ethanol. As a result, the ternary CuxAl1Mn2-x catalysts exhibited superior behaviors to Cu1Al1 and Cu1Mn1. To our delight, Cu1Al1Mn1 had a 95.0 % CHA conversion and 93.6 % selectivity to CHOL along with 97.6 % selectivity to ethanol in a batch reactor. Based on detailed characterization, the ternary CuxAl1Mn2-x catalysts possessed more uniformed dispersion of Cu particles, less aggregation and larger BET specific surface area than the binary catalysts. Furthermore, Cu1Al1Mn1 possessed the highest Cu-0/(Cu-0+Cu+) molar ratio, the highest (Mn2++Mn3+)/Mn4+ molar ratio and the most abundant surface oxygen vacancies, facilitating the adsorption and activation of CHA and hydrogen. In addition, Cu1Al1Mn1 had excellent stability (>500 h) in a fixed-bed reactor.