A dense membrane tube made of Ba0.5Sr0.5Co0.8Fe0.2O3-delta (BSCF) was prepared by plastic extrusion from BSCF oxide synthesized by the complexing EDTA-citrate method. The membrane tube was used in a catalytic membrane reactor for oxidative coupling of methane (OCM) to C-2 without an additional catalyst. At high methane concentration (93%), about 62% C-2 selectivity was obtained, which is higher than that achieved in a conventional reactor using the BSCF as a catalyst. The dependence of the OCM reaction on temperature and methane concentration indicates that the C-2 selectivity in the BSCF membrane reactor is limited by high ion recombination rates. If an active OCM catalyst (La-Sr/CaO) was packed in the membrane tube, C-2 selectivity and CH4 conversion increased compared to the blank run. The highest C-2 yield in the BSCF membrane reactor in presence of the La-Sr/CaO catalyst was about 15%, similar to that in a packed-bed reactor with the same catalyst under-the same conditions. However, the ratio Of C2H4/C2H6 in the membrane reactor was much higher than that in the packed-bed reactor, which is an advantage of the membrane reactor. (c) 2005 Elsevier B.V. All rights reserved.