Preparation of at least one partial oxidation and/or ammoxidation product of propylene

A process for preparing at least one of a partial oxidation product and a partial ammoxidation product of propylene, in which

• a) in a first step, crude propane is subjected to at least one dehydrogenation of the group consisting of homogeneous dehydrogenation, homogenous oxydehydrogenation, heterogeneously catalyzed dehydrogenation and heterogeneously catalyzed oxydehydrogenation, in the presence of oxygen, in the absence of oxygen, or both in the presence and absence of oxygen to give a gas mixture 1 comprising propane and propylene, and
• b) part of the constituents other than propane and propylene present in the gas mixture 1 formed in the first step is, if appropriate, separated off from the gas mixture 1 and/or converted into other compounds so as to produce a gas mixture 1′ comprising propane and propylene and also compounds other than oxygen, propane and propylene from the gas mixture 1 and, in at least one further step,
• c) at least one of gas mixture 1 and gas mixture 1′ as constituent of a gas mixture 2 is subjected to at least one of a heterogeneously catalyzed gas-phase partial oxidation and a partial gas-phase ammoxidation of the propylene present in at least one of the gas mixture 1 and the gas mixture 1′, to form at least one of acrolein, acrylic acid, propylene oxide and acrylonitrile,
• wherein the 1-butene content of the gas mixture 2 is ≦1% by volume.