The present invention relates to a process for preparing a cyclic ketone having from 7 to 16 carbon atoms, which comprises at least the steps (a) oxidation of a composition (I) comprising at least one cyclic alkene which has from 7 to 16 carbon atoms and at least one C—C double bond by means of dinitrogen monoxide to give a composition (A), (b) treatment of the composition (A) with at least one base to give a composition (B), (c) hydrogenation of the composition (B) in the presence of at least one catalyst to give a composition (C), (d) purification of the composition (C), comprising at least the steps (di) thermal treatment of the composition (C) with at least one acid or at least one catalyst comprising at least one transition metal, (dii) further purification by a method selected from the group consisting of distillation, extraction and crystallization.