| abstract |
FIELD: chemistry. n SUBSTANCE: invention relates to a process for producing an unsaturated aldehyde and / or an unsaturated carboxylic acid, each of which corresponds to an alkene, by partially oxidising the alkene using a fixed bed multitube reactor, wherein multiple catalyst layers, which are formed by dividing the reaction tube gas flow direction by N, where N ≥ 3, are provided, and when the change (°C) in hot spot temperature per 1°C change of reaction bath temperature in the catalyst bed 300 hours after the start of the reaction and varying the temperature of the reaction bath is Sn, at least one of the multiple catalyst beds is controlled such that Sn ≤ 6, in which the hot zone means the maximum value of the temperature in the catalyst beds and is the hot zone in the catalyst bed located closest to the inlet side of feed gas, or in the case where the maximum temperature value is absent in the catalyst bed closest to the inlet side of the feed gas, and the temperature of the reaction bath for determining Sn is set in a range where the conversion of propylene ranges from 90% to 99.9%. n EFFECT: present invention is useful in an industrial plant for producing unsaturated aldehydes, unsaturated carboxylic acids. n 7 cl, 1 tbl, 6 ex |