Silicon-glass microfabricated reactors containing silver catalyst were used for oxidative dehydrogenation of 3-methyl-2-buten-1-ol to the corresponding aldehyde. The reactors were safely operated in a wide range of oxygen concentrations, in a temperature range of 310-464 degreesC and residence times of 15-50 ms. The effect of reactant concentrations was examined and it was found that high selectivities were obtained at high alcohol and low oxygen concentration. Conversion of 60-70% with high selectivity (similar to 95%) at alcohol concentrations of 4-7.2 vol% was achieved at oxygen/alcohol ratio of similar to 1 and reaction temperature of 400degrees C. Conversion increased smoothly with temperature and no ignition was observed. Selectivity deteriorated above 415 degreesC due to formation of carbon monoxide, carbon dioxide and higher molecular weight by-products. (C) 2004 Elsevier Ltd. All rights reserved.