Patent ID: 7608734

Claim:
A process for producing unsaturated aldehydes from olefins by fixed-bed catalytic partial oxidation in a shell-and-tube heat exchanger-type reactor, wherein the reactor comprises a reaction zone for producing the unsaturated aldehydes; the reaction zone is divided into two or more shell spaces by at least one partition; each of the divided shell spaces is independently heat-controlled; a heat transfer medium in the first shell space has a temperature ranging from the lowest active temperature of a catalyst layer packed in a reaction tube corresponding to the first shell space to the lowest active temperature of the catalyst layer plus 20° C., wherein the two or more shell spaces are sequentially referred to as the first shell space, the second shell space, . . ., the n th shell space; and the first shell space is controlled in such a manner that it provides an olefin conversion contribution per length as defined in a following equation of 1.2 to 2.5: olefin conversion contribution per length =(mole number of olefins that have reacted in the relevant catalyst layer zone / mole number of the total olefins supplied to the the reaction zone) / volumetric ratio of the revelant catalyst layer zone to the total catalyst layer of the reaction zone.