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X $EVWUDFW In this study the partial oxidation of Q-butane to maleic anhydride (MA) in a solid electrolyte membrane reactor (SEMR) was investigated experimentally. The electrical conductivity of solid electrolyte membrane materials and vanadium phosphorus oxide (VPO) catalyst was investigated with 2-probe impedance spectroscopy. 13% yttria stabilized zirconia was selected as the solid electrolyte membrane material due to its higher oxygen ion conductivity at low temperature. The electrical conductivity of VPO catalyst was found to be too low to directly serve as the anode, therefore an oxide-covered metallic anode structure was designed for the SEMR. Prior to butane oxidation, the reactor was initially characterized with electrochemical methods. The measured oxygen flux through the membrane under electrochemical oxygen pumping agreed well with that predicted from Faraday’s law at low current, while it slightly deviated at high current. Butane oxidation in the SEMR was carried out in three different operation modes: (1) electrochemical membrane reactor (EMR), (2) co-feed membrane reactor (CR), and (3) mixed-feed membrane reactor (MMR). The feasibility of MA synthesis in the EMR was demonstrated with periodic redox and steady-state experiments. The selectivity to MA as well as the MA yield in the EMR was strongly influenced by the imposed current, reaction temperature and butane concentration as well as the anodic flow rate. The studied EMR gave a MA yield of 10% with MA selectivity up to 53% at a reaction temperature of 753 K. The EMR operation gave higher conversion of oxygen but lower selectivity to MA than the CR operation. For the MMR operation, both the positive and negative currents led to a decrease in the MA selectivity compared to the CR operation. By means of comparing the three operation modes, the electrochemically pumped oxygen was found to be more reactive but less selective to MA than gas-phase oxygen, which is mainly related to the different reaction mechanisms between the CR and EMR operations. A simplified reaction-mechanism scheme was finally proposed for butane oxidation carried out in the EMR. It involves not only the same catalytic reaction with well-known oxygen species such as O2, O ∗ (adsorbed) and X O O (lattice oxygen in VPO catalyst) as in the CR but also an electrocatalytic reaction with O and electrophilic oxygen species such as 2 O , − 2 2 O and O.