A microreactor was constructed by inserting a stainless-steel rod into a Pd membrane tube reactor to investigate the effects of microchannel size on the dehydrogenation of cyclohexane to benzene. The I'd membrane, having selective permeability for hydrogen, was coated onto the surface of an (x-alumina porous tube. The dehydrogenation of cyclohexane was carried out at 573 K and atmospheric pressure. The yield of benzene was affected by varying the diameter of the stainless-steel rod, and the yield with the thickest rod was approximately two times higher than that without any rods. The application of the microchannels apparently increased the surface area per volume of the Pd membrane, and thus increased the catalytic rea&tion on the Pd membrane. The present results indicate that the dehydrogenation of cyclohexane is accelerated by applying microchannels. (c) 2006 Elsevier B.V. All rights reserved.