The gas-phase epoxidation of propylene using nitrous oxide as an oxidant over nanostructured iron-containing catalysts was studied. Various types of catalytic systems were used, and the effort was aimed at obtaining propylene oxide as the main product of the reaction. Catalysts prepared on various supports with different porosities, various amounts and types of promoters have been tested. The function of potassium chloride and other promoters was investigated with the aim to understand their effect of the iron incorporation into the silica matrix. It has been found that after a partial removal of KCI from the iron-containing catalyst, a maximum of 54% propylene conversion can be obtained. In the presence of calcium promoter, 96% selectivity of propylene oxide formation was reached at 21% conversion of propylene. (C) 2011 Elsevier B.V. All rights reserved.