METHOD OF PRODUCING CONJUGATED DIENE

PROBLEM TO BE SOLVED: To suppress occurrence of adhesion of soil to a cooling transfer surface by examining conditions easily causing re-volatilization of molybdenum.SOLUTION: A method of producing a conjugated diene comprises supplying a raw material gas containing a 4C or higher monoolefin and a molecular oxygen-containing gas to a heat exchange type catalyst reactor including a molybdenum-containing metal oxide catalyst and carrying out an oxidation hydrogenation reaction by using a coolant while removing the reaction heat. The reaction is continued under the condition where the reaction heat amount (Q1) within the heat exchange type catalyst reactor, the sensible heat difference (Q2) entering and exiting the heat exchange type catalyst reactor and the surface area of the cooling transfer surface meet the relationship: (Q1-Q2)/(U×A)≤100, in which U is the overall electrothermal coefficient of the cooling transfer surface and A is the surface area of the cooling transfer surface.