Mild ring-opening coupling of liquid-phase cyclohexane to diesel components using sulfated metal oxides

Abstract

We have investigated a mild simple synthesis method for ring-opening coupling of liquid-phase cyclohexane to diesel components using various sulfated metal oxides [SO 4 2−/Fe 2O 3 (SF), SO 4 2−/TiO 2 (ST) and SO 4 2−/ZrO 2 (SZ)] under low temperature (333 K) and atmospheric pressure. Neither solvent nor promoters are needed in the reaction system so as to be a clean approach. Operating under these reaction conditions, a maximum activity of 6% was obtained with SF as catalyst, and a significantly high selectivity of 74.5% for nicer diesel components (n-C 14–C 18) was obtained simultaneously. Whereas, ST and SZ displayed low activity for cyclohexane reaction. By utilization of the temperature-programmed desorption of ammonia (NH 3-TPD) measurement and the N 2 adsorption method, the results suggested that a satisfied acid strength distribution and high density of acid sites appeared in SF catalyst in comparison with other catalysts, which may play an important role in the reaction.