An object of the present invention is to provide a method for production of a high purity conjugated diolefin. The method for production of a conjugated diolefin of the present invention comprises steps of supplying a source gas containing a C4 or higher monoolefin and an oxygen-containing gas into a reactor, bringing a catalyst into contact with the gas mixture, compressing a gas containing a conjugated diolefin produced by an oxidative dehydrogenation reaction to obtain a liquefied gas and rinsing the liquefied gas with water.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for producing a catalyst according to the present invention includes: a preparation step of preparing a precursor slurry comprising molybdenum, bismuth, iron, silica, and a carboxylic acid; a drying step of spray-drying the precursor slurry and thereby obtaining a dried particle; and a calcination step of calcining the dried particle, wherein the preparation step comprises: a step (I) of mixing a starting material for silica with the carboxylic acid and thereby preparing a silica-carboxylic acid mixed liquid; and a step (II) of mixing the silica-carboxylic acid mixed liquid, molybdenum, bismuth, and iron.

A method for hydrotreatment of a vacuum-distillate-type hydrocarbon feedstock that contains sulfur and nitrogen compounds is described, with said method for hydrotreatment of a vacuum-distillate-type feedstock comprising a specific concatenation of catalysts that makes it possible to increase the overall activity and the overall stability of the method.

A highly active trimetallic mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A highly active trimetallic mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A highly active trimetallic mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A highly active trimetallic mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A highly active quaternary mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as a catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.

A highly active quaternary mixed transition metal oxide material has been developed. The material may be sulfided to generate metal sulfides which are used as catalyst in a conversion process such as hydroprocessing. The hydroprocessing may include hydrodenitrification, hydrodesulfurization, hydrodemetallation, hydrodesilication, hydrodearomatization, hydroisomerization, hydrotreating, hydrofining, and hydrocracking.