The catalytic partial oxidation of ethanol is experimentally studied over an alumina rhodium coated monolithic honeycomb catalyst at short contact times. The product distribution is analyzed as function of carbon-to-oxygen ratio (C/O) for two different space velocities by a variety of simultaneously applied methods such as Fourier transform infrared spectroscopy, sector mass spectrometry. paramagnetic gas analyzer and gas chromatography combined with mass spectrometry. Low C/O resulted in highly selective synthesis gas production, whereas by-products like methane, ethylene, acetaldehyde and diethyl ether became eminent with increasing C/O. (C) 2010 Elsevier B.V. All rights reserved.