| abstract |
A catalyst for preparing alpha , beta -unsaturated aldehydes by the gas phase catalytic oxidation of alpha , beta -unsaturated hydrocarbons, which catalyst contains as indispensable metal components molybdenum, bismuth and at least one transition metal selected from iron, nickel and cobalt. A chelating agent, or a chelate compound of any of the metals comprising the catalyst, is added to all or some of the starting liquid mixtures during the catalyst preparation stage, whereby to increase the catalytic activity of the catalyst so that the desired alpha , beta -unsaturated aldehyde products such as acrolein and methacrolein can be obtained in high yields. In catalysts of this type, the catalytic activity can be maintained at a high level even if the catalyst does not contain an arsenic component. |