Patent ID: 7439389

Claim:
A process for preparing at least one organic target compound comprising a) heterogeneously catalyzed gas phase partial oxidation of at least one organic starting material compound with molecular oxygen in at least two oxidation reactor systems which comprise catalyst charges and are operated in parallel to obtain at least two product gas streams each comprising the target compound and each stemming from one of the at least two oxidation reactor systems and b) subsequent removal of the at least one target compound from the at least two product gas streams to obtain at least one crude target product stream, in which c) before the removal, mixing together at least two of the at least two product gas streams, or, in the course of the removal, mixing together at least two of any target product-comprising subsequent streams obtained on the route from the at least two product gas streams to the at least one crude target product stream, and/or, after the removal from the at least two product gas streams, mixing together any crude target product streams obtained in the course of the removal, to form a mixture stream, wherein at least one of the catalyst charges of the at least two oxidation reactor systems operated in parallel, over which the target compounds comprised in the mixture stream were formed, comprises at least one portion of catalyst over which the heterogeneously catalyzed gas phase partial oxidation has already been carried out longer than over all portions of catalyst of the at least one other catalyst charge.