Oxidative dehydrogenation of n-butene to buta-1,3-diene with novel iron oxide-based catalyst: Effect of iron oxide crystalline structure

Abstract

• ε-Fe 2 O 3 showed the highest ODH activity among various iron oxide-based catalysts. • The catalytic activity of ε-Fe 2 O 3 was improved by the addition of SiO 2 . • ε-Fe 2 O 3 can be applied to the ODH of cis -but-2-ene as well as but-1-ene. We investigate the effect of the crystalline structure of iron oxide catalysts on oxidative dehydrogenation (ODH) of n-butene. ODH reactions of n-butene were carried out with a fixed-bed flow reactor at 450 °C under a but-1-ene (1-C 4 H 8 ) or cis- but-2-ene ( cis -2-C 4 H 8 )(mL/min)/O 2 (mL/min) flow ratio of 5/2.5. Of the various iron oxide-based catalysts (α-, β-, γ-, ε-Fe 2 O 3 , Fe 3 O 4 , ZnFe 2 O 4 ), ε-Fe 2 O 3 showed the highest ODH activity. To the best of our knowledge, ε-Fe 2 O 3 has never been used for the ODH of n-butene. Moreover, the catalytic performance of ε-Fe 2 O 3 was improved by adding SiO 2 , which is related to the maintenance of its structure and improves its redox property. A high BD selectivity of 65 % and BD yield of 18 % were then obtained for 4 h without deactivation. This catalyst can be applied to the ODH of cis -2-C 4 H 8 and is proposed as the noble high catalytic performance catalyst for the ODH of n-butene.