Catalytic performance of Cu–Mg–Al in the one-step synthesis of 2-ethylhexanol from n-butyraldehyde

Abstract

2-Ethylhexanol (2EHO), an important plasticizer alcohol, is industrially produced through three consecutive reaction processes. In this work, the one-step synthesis of 2EHO from n-butyraldehyde was exploited using Cu/Mg2.5AlOx catalyst. The effect of reaction conditions was investigated and the suitable reaction conditions were obtained as follows: a catalyst mass percentage of 10%, a H2 pressure of 4 MPa, a reaction time of 10 h and a reaction temperature of 180 °C. Under these reaction conditions, the yield of 2-ethylhexanol reached 62.8% and the selectivity ratio of 2-ethylhexanol to n-butanol (S2EHO/SBO) was 5.02. Based on designed experiments and the results of catalyst characterization using NH3-TPD, CO2-TPD and XPS techniques, it was clarified that the synergistic effect of acid–base and the interaction between Mg and Al were responsible for the better catalytic performance of Cu/Mg2.5AlOx. Then a plausible reaction mechanism of n-butyraldehyde self-condensation catalyzed by Cu/Mg2.5AlOx was presumed.