METHOD FOR PRODUCING 1,3-BUTADIENE
The present invention provides a method for producing 1,3-butadiene that is capable of suppressing generation of reaction by-products. The method includes: a step (A) of to obtain a produced gas containing 1,3-butadiene; a step (B) of cooling the produced gas; and a step (C) of separating the produced gas cooled in the step (B) into molecular oxygen and inert gases, and other gases containing 1,3-butadiene, by selective absorption into an absorption solvent. In the method, in the step (A), the raw material gas and a molecular oxygen-containing gas are supplied to a fixed-bed reactor with a composite oxide catalyst containing molybdenum and bismuth; the molar ratio of molecular oxygen to n-butene in the gases is 1.0 to 2.0; and the molar ratio of water vapor to n-butene in the gases supplied to the fixed-bed reactor is not more than 1.2.
1 : A method for producing 1,3-butadiene, the method comprising:
(A) performing an oxidative dehydrogenation reaction, with oxygen in the presence of a metal oxide catalyst, of a raw material gas, which comprises n-butene, to obtain a produced gas comprising 1,3-butadiene;
(B) cooling the produced gas obtained in (A); and
(C) separating the produced gas cooled in (B) into molecular oxygen and inert gases, and other gases comprising 1,3-butadiene, by selective absorption into an absorption solvent, wherein:
in (A), the raw material gas and a molecular oxygen-containing gas, as a minimum, are supplied to a fixed-bed reactor, wherein an inside of the fixed-bed reactor includes the metal oxide catalyst, which is a composite oxide catalyst comprising molybdenum and bismuth;
a molar ratio of molecular oxygen to n-butene (molecular oxygen/n-butene) in the gases supplied to the fixed-bed reactor is 1.0 to 2.0; and
a molar ratio of water vapor (water) to n-butene (water/n-butene) in the gases supplied to the fixed-bed reactor is not more than 1.2.
2 : The method for producing 1,3-butadiene according to claim 1 , wherein in the produced gas obtained in (A), a yield of a carbonyl compound is not more than 1.34 mol %, and a yield of a heterocyclic compound is not more than 3.01 mol %.
3 : The method for producing 1,3-butadiene according to claim 1 , wherein in (B), the produced gas comes into contact with a cooling medium so that the produced gas is cooled, and an yield of organic acids in the cooling medium that has been in contact with the produced gas is not more than 2 mol %.
4 : The method for producing 1,3-butadiene according to claim 1 , wherein in (A), the molar ratio of water vapor to n-butene in the gases supplied to the fixed-bed reactor is not more than 0.6.