The modification of Ho2O3 with BaCl2 for the oxidative dehydrogenation of ethane

The addition of BaCl2 to Ho2O3 could improve considerably both the C2H6 conversion and C2H4 selectivity in the oxidative dehydrogenation of ethane (ODE) reaction. At 640 degrees C, C2H6:O-2:N-2=2:1:4, and W/F=0.6 g s ml(-1), C2H6 conversion of ca. 57 % , C2H4 selectivity of ca. 68 %, and C2H4 yield of ca. 39 % were observed over the 50 mol% BaCl2/Ho2O3 catalyst within a reaction period of 40 h. We conclude that the addition of BaCl2 to Ho2O3 Can 1. enhance oxygen activation, 2. prevent a certain amount of active basic sites from being occupied by CO2, and 3. suppress C2H4 deep oxidation. The presence of Cl- ions could induce the formation of new active sites suitable for C2H4 generation. For the 50 mol% BaCl2/Ho2O3 catalyst, chlorine leaching was insignificant during the ODE reactions. This could be the reason why the catalyst was stable within the reaction period of 40 h. (C) 1999 Elsevier Science B.V. All rights reserved.