An influence of gas-liquid (G-L) interface position within the membrane wall, which is a key parameter determining the gas-liquid mass transfer, and its effect on the efficiency of a ceramic membrane as a three-phase reactor was studied. This paper demonstrates that it is possible to displace liquid from the membrane wall by applying a sufficient trans-membrane pressure difference and control the position of gas-liquid interface. By supplanting the liquid-phase from the membrane pores it is possible to reduce the diffusion path of gas molecules, which resulted in considerable increase of the gas-liquid mass transfer. Ascendance of the gas-liquid interface position on the effectiveness of the catalytic membrane reactor was studied by conducting catalytic liquid-phase nitrite hydrogenation. A catalytic membrane was prepared via metallic palladium depositions within the porous structure of tubular membrane using the incipient wetness impregnation technique. Performed experimental study established the effects of the process parameters (diffusion path of the reactant, re-circulation rate...) on the overall performance of the membrane reactor. The obtained results were evaluated and compared to those obtained in conventional slurry reactor. (C) 2003 Elsevier B.V. All rights reserved.