The conversion of propane in the presence of oxygen over alumina has been studied using a fixed bed flow reactor. The interaction of the same catalyst with propane, propene, isopropanol and acetone has also been investigated, with additional gas-phase monitoring, in an FT-IR cell. Alumina looks active in the catalytic conversion of propane to propene, with the production of CO2, CO, ethylene, methane as the main by-products, depending On the reaction temperature. Higher hydrocarbons such as butenes, butadiene, benzene and toluene are also found. This reactivity is mainly attributed to the weak but not negligible Bronsted acidity of the surface OH's of alumina, possibly activating propane in the form of isopropoxides and allowing oligomerization of propene. This shows the detrimental effect of the uncovered alumina support in the case of alumina-supported catalysts for propane oxydehydrogenation and explains the positive role of doping with basic neutralizing agents such as potassium.