METHOD FOR PRODUCING PURE 1,3-BUTADIENE Russian patent published in 2021 - IPC C07C7/04 B01D3/14 C07C7/08 C07C11/167 

FIELD: chemistry.

SUBSTANCE: invention relates to a method for producing pure 1,3-butadiene from the untreated C₄ fraction as a result of extractive distillation with a selective solvent, in which a) the liquid untreated C₄ fraction is fed into the feed zone of the pre-distillation column, which in the middle section is divided by a partition, oriented mainly in the longitudinal direction of the pre-distillation column, into the feed zone and the side output zone, the first low-boiling fraction containing C₃ hydrocarbons in the form of a head stream and the gaseous C₄ fraction in the form of a side stream from the side outlet zone and the first high-boiling fraction in the form of a cubic stream are discharged, b) in at least one extraction column, the gaseous C₄ fraction is brought into contact with a selective solvent, and a head fraction containing butanes and butenes and a cubic fraction containing 1,3-butadiene and a selective solvent are obtained, c) in at least one degassing column, crude 1,3-butadiene is desorbed from the cubic fraction, the degassed selective solvent is obtained and the degassed selective solvent is sent back to the extraction column, and (d) at least part of the crude 1,3-butadiene is fed into the fine distillation column and the second high-boiling fraction is separated, the exhaust gaseous stream is discharged, and the second high-boiling fraction is sent back to the lower section of the pre-distillation column.

EFFECT: proposed method allows one to maintain the production mode for a long time and at the same time achieve a high yield of pure 1,3-butadiene.

11 cl, 1 dwg, 3 tbl, 3 ex