| abstract |
A method for producing a conjugated diolefin is configured as follows. A monoolefin having four or more carbon atoms is fed from a monoolefin feed nozzle(s) installed at n place(s) (n = 1, 2, ..., n). In addition, at least 50% or more of a total amount of an oxygen-containing gas is fed from an oxygen-containing gas feed nozzle located at a bottom of a fluidized bed reactor. Furthermore, the monoolefin feed nozzles at distances a1, a2, ..., an from the oxygen-containing gas feed nozzle feed the monoolefin having four or more carbon atoms at ratios of b1, b2, ..., bn (b1 + b2 + ... + bn = 1), respectively, and an arithmetic mean value represented by the following formula and obtained from the above distances and the above ratios is 100 mm or more. arithmetic mean value = a ¢ 1 * b ¢ 1 + a ¢ 2 * b ¢ 2 + ¦ + an * bn |