Oxidative dehydrogenation of isobutane on chromium oxide-based catalyst
- Additional Document Info
- View All
Isobutane oxidative dehydrogenation offers a prospect of cheaper and environment friendly route to isobutene. The reaction has been studied at 250 °C, 1 atm and feed flow rate of 75 cm3/min over supported chromium oxide-based catalysts. Effects of various supports (Al 2O3, MgO, TiO2 and SiO2), catalyst precursors (K2Cr2O7, CaCr2O 7·H2O, CrO3, CrK(SO4) 2·12H2O and Cr(NO3)3· 9H2O) and binary mixed metal oxide catalysts of the form Cr-M-oxide/γ-Al2O3 (where M is V, Ni, Co, Mo, W, Ho, La, Li or Bi) were investigated. The supported catalysts are ranked (based on isobutene yields at 250 °C) as; Cr-Mg-O (3.4%) = Cr-Si-O (3.4%) < Cr-Ti-O (4.5%) < Cr-Al-O (6.0%). The performances of the catalysts showed strong dependence on the precursor used. The 10 wt.% Cr-Al-O prepared using K 2Cr2O7 and CrK(SO4) 2·2H2O exhibited the lowest isobutene yields of 0.14 and 0.3%, respectively. Partial substitution of chromium ions with nickel or tungsten exhibited minor increase in selectivity to isobutene of about 6% at comparable isobutane conversions. Substitution with other metals show similar or inferior performance compared with the base catalyst. Thus, showing that chromium oxide-based catalysts are active for the reaction and their performance could be improved by appropriate choice of active component precursor, support and additives. © 2004 Elsevier B.V. All rights reserved.
author list (cited authors)
Jibril, B. Y., Elbashir, N. O., Al-Zahrani, S. M., & Abasaeed, A. E.